TUMOR NECROSIS FACTOR RECEPTOR 5

Abstract: The present invention relates to a novel human gene encoding a polypeptide which is a member of the TNF receptor family, and has now been found to bind TRAIL. More specifically, an isolated nucleic acid molecule is provided encoding a human polypeptide named tumor necrosis factor receptor-5, sometimes referred to as "TNFR-5" or "TR5", and now referred to hereinafter as "TRAIL receptor without intracellular domain" or "TRID". TRID polypeptides are also provided, as are vectors, host cells, and recombinant methods for producing the same. The invention further relates to screening methods for identifying agonists or antagonists of TRAIL polypeptide activity. Also provided are diagnostic and therapeutic methods utilizing such compositions.

Description: Tumor Necrosis Factor Receptor 5 Background of the Invention Field of th e In vention The present invention relates to a novel human gene encoding a polypeptide which is a member of the TNF receptor family, and has now been found to bind TRAIL. More specifically, an isolated nucleic acid molecule is provided encoding a human polypeptide named tumor necrosis factor receptor-5 , sometimes referred to as "TNFR-5" or "TR5," and now referred to hereinafter as "TRAIL receptor without intracellular domain" or "TRID." TRID polypeptides are also provided, as are vectors, host cells, and recombinant methods for producing the same. The invention further relates to screening methods for identifying agonists or antagonists of TRID polypeptide activity. Also provided are diagnostic and therapeutic methods utilizing such compositions. Related Art Many biological actions, for instance, response to certain stimuli and natural biological processes, are controlled by factors, such as cytokines. Many cytokines act through receptors by engaging the receptor and producing an intracellular response. For example, tumor necrosis factors (TNF) alpha and beta are cytokines, which act through TNF receptors to regulate numerous biological processes, including protection against infection and induction of shock and inflammatory disease. The TNF molecules belong to the "TNF-ligand" superfamily, and act together with their receptors or counter-ligands, the "TNF-receptor" superfamily. So far, nine members of the TNF ligand superfamily have been identified and ten members of the TNF-receptor superfamily have been characterized. Among the ligands, there are included TNF- , lymphotoxin-o. (LT-α, also known as TNF-β), LT-β (found in complex heterotrimer LT- 2-β, FasL, CD40L, CD27L, CD30L, 4-1BBL, OX40L and nerve growth factor (NGF). The superfamily of TNF receptors includes the p55TNF receptor, p75TNF receptor, TNF receptor-related protein. FAS antigen or APO-1, CD40, CD27, CD30, 4-1BB, OX40, low affinity p75 and NGF-receptor (Meager, A., Biologicals 22:291-295 (1994)). Many members of the TNF-ligand superfamily are expressed by activated T-cells, implying that they are necessary for T-cell interactions with other cell types which underlie cell ontogeny and functions (Meager, A., supra). Considerable insight into the essential functions of several members of the TNF receptor family has been gained from the identification and creation of mutants that abolish the expression of these proteins. For example, naturally occurring mutations in the FAS antigen and its ligand cause lymphoproliferative disease (Watanabe-Fukunaga, R. et al., Nature 356:314 (1992)), perhaps reflecting a failure of programmed cell death. Mutations of the CD40 ligand cause an X-linked immunodeficiency state characterized by high levels of immunoglobulin M and low levels of immunoglobulin G in plasma, indicating faulty T-cell-dependent B-cell activation (Allen, R.C. et al., Science 259:990 (1993)). Targeted mutations of the low affinity nerve growth factor receptor cause a disorder characterized by faulty sensory innovation of peripheral structures (Lee, K.F. et al., Cell 69:131 (1992)). TNF and LT-α are capable of binding to two TNF receptors (the 55- and 75-kd TNF receptors). A large number of biological effects elicited by TNF and LT-α. acting through their receptors, include hemorrhagic necrosis of transplanted tumors, cytotoxicity, a role in endotoxic shock, inflammation, immunoregulation, proliferation and anti-viral responses, as well as protection against the deleterious effects of ionizing radiation. TNF and LT-α are involved in the pathogenesis of a wide range of diseases, including endotoxic shock, cerebral malaria, tumors, autoimmune disease, AIDS and graft-host rejection (Beutler, B. and Non Huffel, C, Science 264:661-668 (1994)). Mutations in the p55 Receptor cause increased susceptibility to microbial infection. Moreover, an about 80 amino acid domain near the C-terminus of TΝFR1 (p55) and Fas was reported as the "death domain," which is responsible for transducing signals for programmed cell death (Tartaglia et al., Cell 74:845 (1993)). Apoptosis, or programmed cell death, is a physiologic process essential for the normal development and homeostasis of multicellular organisms (H. Steller, Science 261, 1445-1449 (1995)). Derangements of apoptosis contribute to the pathogenesis of several human diseases including cancer, neurodegenerative disorders, and acquired immune deficiency syndrome (C.B. Thompson, Science 267, 1456-1462 (1995)). One mechanism of immune mediated killing is the engagement of death receptors. Recently, much attention has focused on the signal transduction and biological function of two cell surface death receptors, Fas/APO-1 and TNFR-1 (J.L. Cleveland et al., Cell 81, 479-482 (1995); A. Fraser, et al, Cell 85, 781-784 (1996); S. Nagata et al., Science 261, 1449-56 (1995)). Both are members of the TNF receptor family which also include TNFR-2, low affinity NGFR, CD40, and CD30, among others (CA. Smith et al. , Science 248, 1019-23 (1990); M. Tewari et al, in Modular Texts in Molecular and Cell Biology M. Purton, Heldin, Carl, Ed. (Chapman and Hall, London, 1995). While family members are defined by the presence of cysteine-rich repeats in their extracellular domains, Fas/APO-1 and TNFR-1 also share a region of intracellular homology, appropriately designated the "death domain", which is distantly related to the Drosophila suicide gene, reaper (P. Golstein, et al, Cell 81. 185-186 (1995); K. White et al, Science 264, 677-83 (1994)). This shared death domain suggests that both receptors interact with a related set of signal transducing molecules that, until recently, remained unidentified. Activation of Fas/APO-1 recruits the death domain-containing adapter molecule FADD/MORT1 (A.M. Chinnaiyan etal, Cell 81, 505-12 (1995); M. P. Boldin et al., J. Biol Chem 270, 7795-8 (1995); F.C. Kischkel etal, EMBO 14, 5579-5588 (1995)), which in turn binds and presumably activates FLICE/MACH 1 , a member of the ICE/CED-3 family of pro-apoptotic proteases (M. Muzio et al , Cell 85, 817-827 (1996); M.P. Boldin et al, Cell 85, 803-815 (1996)). While the central role of Fas/APO-1 is to trigger cell death, TNFR-1 can signal an array of diverse biological activities-many of which stem from its ability to activate NF-kB (L.A. Tartaglia etal, Immunol Today 13, 151-3 (1992)). Accordingly, TNFR-1 recruits the multivalent adapter molecule TRADD, which like FADD, also contains a death domain (H. Hsu et al, Cell 81, 495-504 (1995); H. Hsu, et al, Cell 84, 299-308 (1996)). Through its associations with a number of signaling molecules including FADD, TRAF2, and RIP, TRADD can signal both apoptosis and NF-kB activation (H. Hsu et al, Cell 84, 299-308 (1996); H. Hsu, et al, Immunity 4, 387-396 (1996)). Recently, a new apoptosis -inducing TNF ligand has been discovered. S.R. Wiley et al, Immunity J,673-682 (1995) named the molecule - "TNF-related apoptosis-inducing ligand" or simply "TRAIL." The molecule has also been called "Apo-2 ligand" or "Apo-2L." R.M. Pitt et al, J. Biol Chem. 277,12687-12690 (1996). This molecule was also disclosed in co-pending U.S. provisional application no. 60/013,405. For convenience, the molecule will be referred to herein as TRAIL. Unlike FAS ligand, whose transcripts appear to be largely restricted to stimulated T-cells, significant levels of TRAIL are detected in many human tissues (e.g. , spleen, lung, prostate, thymus, ovary, small intestine, colon, peripheral blood lymphocytes, placenta, kidney), and is constitutively transcribed by some cell lines. It has been shown that TRAIL acts independently from the Fas ligand (Wiley et al, supra). It has also been shown that TRAIL activates apoptosis rapidly, within a time frame that is similar to death signalling by Fas/Apo-IL, but much faster than TNF-induced apoptosis. S.A. Marsters et al, Current Biology 6, 750-752 (1996). The inability of TRAIL to bind TNFR-1, Fas, or the recently identified DR3, suggests that TRAIL may interact with a unique receptor(s). The effects of TNF family ligands and TNF family receptors are varied and influence numerous functions, both normal and abnormal, in the biological processes of the mammalian system. There is a clear need, therefore, for identification and characterization of such receptors and ligands that influence biological activity, both normally and in disease states. In particular, there is a need to isolate and characterize additional novel receptors that bind TRAIL. Summary of the Invention The present invention provides isolated nucleic acid molecules comprising, or alternatively consisting of, a polynucleotide encoding the TRID polypeptide having the amino acid sequence shown in SEQ ID NO:2, or the amino acid sequence encoded by the cDNA clone deposited as ATCC Deposit Number 97798 on November 20, 1996. The nucleotide sequence determined by sequencing the deposited TRID clone, which is shown in SEQ ID NO: 1 contains an open reading frame encoding a polypeptide of about 259 amino acid residues, with a leader sequence of about 26 amino acids. The present invention also relates to recombinant vectors, which include the isolated nucleic acid molecules of the present invention, and to host cells containing the recombinant vectors, as well as to methods of making such vectors and host cells and methods for using them for production of TRID polypeptides or peptides by recombinant techniques. The invention further provides an isolated TRID polypeptide having an amino acid sequence encoded by a polynucleotide described herein. The present invention also provides diagnostic assays such as quantitative and diagnostic assays for detecting levels of TRID protein. Thus, for instance, a diagnostic assay in accordance with the invention for detecting expression of TRID, or soluble form thereof, may be used to detect the ability of normal tissue to withstand or be protected from the deleterious effects of TRAIL, such as TRAIL-induced apoptosis. Tumor Necrosis Factor (TNF) family ligands are known to be among the most pleiotropic cytokines, inducing a large number of cellular responses, including cytotoxicity, anti-viral activity, immunoregulatory activities, and the transcriptional regulation of several genes. Cellular response to TNF-family ligands include not only normal physiological responses, but also diseases associated with increased apoptosis or the inhibition of apoptosis. Apoptosis - programmed cell death - is a physiological mechanism involved in the deletion of peripheral T lymphocytes of the immune system, and its dysregulation can lead to a number of different pathogenic processes. Diseases associated with increased cell survival, or the inhibition of apoptosis, include cancers, autoimmune disorders, viral infections, inflammation, graft vs. host disease, acute graft rejection, and chronic graft rejection. Diseases associated with increased apoptosis include AIDS, neurodegenerative disorders, myelodysplastic syndromes, ischemic injury, toxin-induced liver disease, septic shock, cachexia and anorexia. Thus, the invention further provides a method for enhancing apoptosis induced by a TNF-family ligand, such as TRAIL, which involves administering to a cell which expresses the TRID polypeptide an effective amount of an antagonist capable of decreasing TRID's ability to bind TRAIL. Preferably, TRID binding is decreased to treat a disease wherein decreased apoptosis is exhibited. In a further aspect, the present invention is directed to a method for inhibiting apoptosis induced by a TNF-family ligand, such as TRAIL, which involves administering to a cell an effective amount of TRID or an agonist capable of increasing TRID activity. Preferably, TRID activity is increased to treat a disease wherein increased apoptosis is exhibited. Whether any candidate "agonist" or "antagonist" of the present invention can enhance or inhibit apoptosis can be determined using art-known TNF-family ligand/receptor cellular response assays, including those described in more detail below. Thus, in a further aspect, a screening method is provided for determining whether a candidate agonist or antagonist is capable of enhancing or inhibiting a cellular response to a TNF-family ligand, such as TRAIL. The method involves contacting cells which co-expresses the TRID polypeptide and a second TNFR with a candidate compound and a TNF-family ligand (e.g., TRAIL), assaying a cellular response, and comparing the cellular response to a standard cellular response, the standard being assayed when contact is made with the ligand in absence of the candidate compound, whereby an increased cellular response over the standard indicates that the candidate compound is a TRID antagonist and a decreased cellular response compared to the standard indicates that the candidate compound is TRID agonist. By the invention, a cell expressing the TNFR polypeptide can be contacted with either an endogenous or exogenously administered TNF-family ligand, such as TRAIL. Brief Description of the Figures Figure 1 A-B shows the nucleotide sequence (SEQ ID NO : 1 ) and deduced amino acid sequence (SEQ ID NO:2) of TRID. Figure 2A-P shows an alignment created by the Clustal method using the Megaline program in the DNAstar suite comparing the amino acid sequences of TNFR-5 (now called "TRID," denoted as "TNFR-like" in the figure), with other TNF receptors, as follows: TNFR1 (SEQ ID NO:3); TNFR2 (SEQ ID NO:4); NGFR (SEQ ID NO:5) LTbR (SEQ ID NO:6); FAS (SEQ ID NO:7); CD27 (SEQ ID NO:8); CD30 (SEQ ID NO:9); CD40 (SEQ ID NO.10); 4-lBB (SEQ ID NO: 1 1); OX40 (SEQ IDNO:12); VC22 (SEQ IDNO:13); and CRMB (SEQ ID NO: 14). Residues that match the consensus are shaded. Figure 3 shows an analyses of the TRID amino acid sequences. Alpha, beta, turn and coil regions; hydrophilicity and hydrophobicity; amphipathic regions; flexible regions; antigenic index and surface probability are shown, as predicted for the amino acid sequence depicted in SEQ ID NO:2 using the default parameters of the recited computer program. The "Antigenic Index - Jameson- Wolf ' graphs, indicate the location of the highly antigenic regions of the proteins, i.e., regions from which epitope-bearing peptides of the invention may be obtained. Figure 4 shows the nucleotide sequence of gene fragments related to the TRID gene of the present invention, including: HPRCB54R (SEQ ID NO: 15), HSJAU57RA (SEQ IDNO:16), HELBP70R (SEQ ID NO: 17), and HUSCB54R (SEQ ID NO: 18) all of which are related to SEQ ID NO: 1. Figure 5A is an immunoblot showing that TRID-Fc (as well as DR4 and DR5) specifically bound TRAIL, but not the related cytotoxic ligand TNFα. The bottom panel of Fig. 5A shows the input Fc-fusions present in the binding assays. Figure 5B is a bar graph showing that TRID-Fc blocked the ability of TRAIL to induce apoptosis. The data (mean ± SD) shown in Fig. 5B are the percentage of apoptotic nuclei among total nuclei counted (n=4). Figure 5C is a bar graph showing that TRID-Fc had no effect on TNFα-induced apoptosis under conditions where TNFRl-Fc completely abolished TNFα killing. Figure 6 is a bar graph showing that MCF7 cells expressing TRID were protected from TRAIL-induced apoptosis, as were cells expressing the virally encoded caspase inhibitor CrmA. Detailed Description of the Preferred Embodiments The present invention provides isolated nucleic acid molecules comprising, or alternatively consisting of, a polynucleotide encoding a TRID polypeptide, having the amino acid sequence shown in SEQ ID NO:2. which was determined by sequencing a cloned cDNA. The nucleotide sequence shown in SEQ ID NO: 1 was obtained by sequencing the HPRCB54 clone, which was deposited on November 20, 1996 at the American Type Culture Collection, 10801 University Boulevard, Manassas, Virginia, 20110-2209, and given accession number ATCC 97798. The deposited clone is inserted in the pBluescript SK(-) plasmid (Stratagene, La Jolla, CA). The TRID protein of the present invention has an amino acid sequence which is 21.7% identical to and shares multiple conserved cysteine rich domains with the translation product of the human nerve growth factor (hNGF) mRNA (SEQ ID NO:5) as illustrated in Figure 2A-P. hNGF is thought to play an important role in the development, survival, apoptosis and function of neurons (Lee, F.K. et al, Cell 69:131) and lymphocytes (Torcia, M. et al, Cell 85:3369 (1996)). Sequence alignment and comparison reveal that TRID's extracellular cysteine-rich domain to be strikingly similar to the corresponding domains of both DR4 and DR5 with 69% and 52% amino acid identity, respectively. In addition, like DR4 and DR5, TRID was also found to be homologous to the cysteine-rich domain in CAR1, a chicken TNF receptor family member with amino acid identities ranging from 42-48% (J. Brojatsh et al, Cell 87: 1 (1996)). A potential protective role for TRID was suggested by the finding that its transcript was detectable in many normal human tissues but not in most transformed cell lines. TRID has an extracellular TRAIL binding domain and a transmembrane domain but, surprisingly, lacks a putative intracellular signalling domain, in keeping with the possibility that this receptor does not signal following ligand binding. Given the absence of an intracellular domain, this receptor was termed "TRID" for TRAIL Receptor Without an Intracellular Domain. Nucleic Acid Molecules Unless otherwise indicated, all nucleotide sequences determined by sequencing a DNA molecule herein were determined using an automated DNA sequencer (such as the Model 373 from Applied Biosystems, Inc., Foster City, CA), and all amino acid sequences of polypeptides encoded by DNA molecules determined herein were predicted by translation of a DNA sequence determined as above. Therefore, as is known in the art for any DNA sequence determined by this automated approach, any nucleotide sequence determined herein may contain some errors. Nucleotide sequences determined by automation are typically at least about 90% identical, more typically at least about 95% to at least about 99.9% identical to the actual nucleotide sequence of the sequenced DNA molecule. The actual sequence can be more precisely determined by other approaches including manual DNA sequencing methods well known in the art. As is also known in the art, a single insertion or deletion in a determined nucleotide sequence compared to the actual sequence will cause a frame shift in translation of the nucleotide sequence such that the predicted amino acid sequence encoded by a determined nucleotide sequence will be completely different from the amino acid sequence actually encoded by the sequenced DNA molecule, beginning at the point of such an insertion or deletion. By "nucleotide sequence" of a nucleic acid molecule or polynucleotide is intended, for a DNA molecule or polynucleotide, a sequence of deoxyribonucleotides. and for an RNA molecule or polynucleotide, the corresponding sequence of ribonucleotides (A, G. C and U), where each thymidine deoxyribonucleotide (T) in the specified deoxyribonucleotide sequence is replaced by the ribonucleotide uridine (U). Using the information provided herein, such as the nucleotide sequence set out in SEQ ID NO:l, a nucleic acid molecule of the present invention encoding a TRID polypeptide may be obtained using standard cloning and screening procedures, such as those for cloning cDNAs using mRNA as starting material. Illustrative of the invention, the TRID nucleic acid molecule described in SEQ ID NO: 1 was discovered in a cDNA library derived from prostate tissue. Additional clones of the same gene were also identified in cDNA libraries from the following tissues: endothelial cells, stimulated monocytes, and kerotinocytes. The determined nucleotide sequence of the TRID cDNA of SEQ ID NO: 1 contains an open reading frame encoding a protein of about 259 amino acid residues, with an initiation codon at nucleotide positions 183-185 of the nucleotide sequences in SEQ ID NO: 1. The open reading frame of the TRID gene shares sequence homology with the translation product of the human mRNA for NGFR, including the following conserved domains : (a) a soluble extracellular domain of about 214 amino acids (amino acid residues from about 27 to about 240 in SEQ ID NO:2); (b) a transmembrane domain of about 19 amino acids (amino acid residues from about 241 to about 259 in SEQ ID NO:2); and (c) a cysteine rich domain of about 97 amino acids (amino acid residues from about 53 to about 150 in SEQ ID NO:2). As one of ordinary skill would appreciate, due to the possibility of sequencing errors discussed above, the actual complete TRID polypeptide encoded by the deposited cDNAs, which comprise about 259 amino acids, may be somewhat longer or shorter. More generally, the actual open reading frames may be anywhere in the range of ±20 amino acids, more likely in the range of ±10 amino acids, of that predicted from the first methionine codon from the N-terminus shown in SEQ ID NO:l, which is in-frame with the translated sequences shown in each respective figure. It will further be appreciated that, depending on the analytical criteria used for identifying various functional domains, the exact "address" of the extracellular, cysteine rich, and transmembrane domain(s) of the TNFR polypeptides may differ slightly from the predicted positions above. For example, the exact location of the extracellular domain, cysteine-rich domain, and transmembrane domain in SEQ ID NO:2 may vary slightly (e.g. , the address may "shift" by about 1 to about 20 residues, more likely about 1 to about 5 residues) depending on the criteria used to define the domain. In this case, the beginning of the transmembrane domain and the end of the extracellular domain were predicted on the basis of the identification of the hydrophobic amino acid sequence in the above indicated positions, as shown in Figure 3. In any event, as discussed further below, the invention further provides polypeptides having various residues deleted from the N-terminus of the complete TRID, including polypeptides lacking one or more amino acids from the N-terminus of the extracellular domain described herein, which constitute soluble forms of the extracellular domain of the TRID protein. Leader and Mature Sequences The amino acid sequence of the TRID protein includes a leader sequence and a mature protein, as shown in SEQ ID NO:2. More in particular, the present invention provides nucleic acid molecules encoding mature forms of the TRID protein. Thus, according to the signal hypothesis, once export of the growing protein chain across the rough endoplasmic reticulum has been initiated, proteins secreted by mammalian cells have a signal or secretory leader sequence which is cleaved from the complete polypeptide to produce a secreted "mature" form of the protein. Most mammalian cells and even insect cells cleave secreted proteins with the same specificity. However, in some cases, cleavage of a secreted protein is not entirely uniform, which results in two or more mature species of the protein. Further, it has long been known that the cleavage specificity of a secreted protein is ultimately determined by the primary structure of the complete protein, that is, it is inherent in the amino acid sequence of the polypeptide. Therefore, the present invention provides a nucleotide sequence encoding a mature TRID polypeptide having the amino acid sequence encoded by a cDNA clone identified as ATCC Deposit No. 97798. By the "mature TRID polypeptide having the amino acid sequence encoded by a cDNA clone in ATCC Deposit No. 97798" is meant the mature form(s) of the protein produced by expression in a mammalian cell (e.g. , COS cells, as described below) of the complete open reading frame encoded by the human DNA sequence of the clone contained in the deposited plasmid. Methods for predicting whether a protein has a secretory leader as well as the cleavage point for that leader sequence are available. For instance, the method ofMcGeoc (Virus Res. 5:271-286 (1985)) uses the information from a short N- terminal charged region and a subsequent uncharged region of the complete (uncleaved) protein. The method of von Heinje (Nucleic Acids Res. 14:4683- 4690 (1986)) uses the information from the residues surrounding the cleavage site, typically residues -13 to +2 where +1 indicates the amino terminus of the mature protein. The accuracy of predicting the cleavage points of known mammalian secretory proteins for each of these methods is in the range of 15-80% (von Heinje, supra). However, the two methods do not always produce the same predicted cleavage point(s) for a given protein. In the present case, the deduced amino acid sequence of the complete TRID polypeptide was analyzed by a computer program "PSORT." See, K. Nakai and M. Kanehisa, Genomics 14:891-91 1 (1992). PSORT is an expert system for predicting the cellular location of a protein based on the amino acid sequence. As part of this computational prediction of localization, the methods of McGeoch and von Heinje are incorporated. The analysis by the PSORT program predicted the cleavage sites between amino acids 26 and 27 in SEQ ID NO:2. Thereafter, the complete amino acid sequences were further analyzed by visual inspection, applying a simple form of the (-1,-3) rule of von Heinje. von Heinje, supra. Thus, the leader sequence for the TRID protein is predicted to consist of amino acid residues from about 1 to about 26, underlined in SEQ ID NO:2, while the mature TRID protein is predicted to consist of residues from about 27 to about 259 in SEQ ID NO:2. As one of ordinary skill would appreciate, due to the possibilities of sequencing errors, as well as the variability of cleavage sites for leaders in different known proteins, the mature TRID polypeptide encoded by the deposited cDNA comprises about 233 amino acids, but may be anywhere in the range of about 223 to about 243 amino acids, and the predicted leader sequence of this protein is about 26 amino acids, but may be anywhere in the range of about 16 to about 36 amino acids. As indicated, nucleic acid molecules of the present invention may be in the form of RNA, such as mRNA, or in the form of DNA, including, for instance, cDNA and genomic DNA obtained by cloning or produced synthetically. The DNA may be double-stranded or single-stranded. Single-stranded DNA or RNA may be the coding strand, also known as the sense strand, or it may be the non-coding strand, also referred to as the anti-sense strand. By "isolated" nucleic acid molecule(s) is intended a nucleic acid molecule, DNA, or RNA, which has been removed from its native environment. For example, recombinant DNA molecules contained in a vector are considered isolated for the purposes of the present invention. Further examples of isolated DNA molecules include recombinant DNA molecules maintained in heterologous host cells or purified (partially or substantially) DNA molecules in solution. Isolated RNA molecules include in vivo or in vitro RNA transcripts of the DNA molecules of the present invention. Isolated nucleic acid molecules according to the present invention further include such molecules produced synthetically. However, a nucleic acid molecule contained in a clone that is a member of a mixed clone library (e.g., a genomic or cDNA library) and that has not been isolated from other clones of the library (e.g., in the form of a homogeneous solution containing the clone without other members of the library) or a chromosome isolated or removed from a cell or a cell lysate (e.g. , a "chromosome spread", as in a karyotype), is not "isolated" for the purposes of this invention. Isolated nucleic acid molecules of the present invention include DNA molecules comprising, or alternatively consisting of, an open reading frame (ORF) shown in SEQ ID NO: 1 ; DNA molecules comprising, or alternatively consisting of, the coding sequence for the mature TRID protein; and DNA molecules which comprise, or alternatively consist of, a sequence substantially different from those described above, but which, due to the degeneracy of the genetic code, still encode the TRID protein. Of course, the genetic code is well known in the art. Thus, it would be routine for one skilled in the art to generate such degenerate variants. In addition, the invention provides nucleic acid molecules having nucleotide sequences related to extensive portions of SEQ ID NO: 1 , which have been determined from the following related cDNA clones: HELBP70R (SEQ ID NO: 17), HPRCB54R (SEQ ID NO: 15), HSJAU57RA (SEQ ID NO: 16) and HUSCB54R (SEQ ID NO: 18). The nucleotide sequences of each of these gene fragments is shown in Figure 4. In another aspect, the invention provides isolated nucleic acid molecules encoding the TRID polypeptide having an amino acid sequence as encoded by the cDNA clone contained in the plasmid deposited as ATCC Deposit No. 97798. In a further embodiment, nucleic acid molecules are provided that encode the mature TRID polypeptide or the full length TRID polypeptide each lacking the N-terminal methionine. The invention further provides an isolated nucleic acid molecule having the nucleotide sequence shown in SEQ ID NO:l or the nucleotide sequence of the TRID cDNA contained in the above-described deposited clone, or a nucleic acid molecule having a sequence complementary to one of the above sequences. Such isolated molecules, particularly DNA molecules, are useful as probes for gene mapping, by in situ hybridization with chromosomes, and for detecting expression of the TRID gene in human tissue, for instance, by Northern blot analysis. The present invention is further directed to fragments of the isolated nucleic acid molecules described herein. By a fragment of an isolated nucleic acid molecule having the nucleotide sequence of the deposited cDNA (the cDNA contained in the plasmid deposited as ATCC Deposit No.97798) or the nucleotide sequence shown in SEQ ID NO: 1 are intended DNA fragments at least 20 nt, and more preferably at least 30 nt in length, and even more preferably, at least about 40, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1050, 1 100, 1150, 1200, 1250, 1300, 1350, 1400, 1450, or 1500 nt in length, which are useful as DNA probes as discussed herein. Of course, DNA fragments corresponding to most, if not all, of the nucleotide sequence shown in SEQ ID NO: 1 are also useful as DNA probes. By a fragment at least 20 nt in length, for example, is intended fragments which include 20 or more contiguous bases from the nucleotide sequence of a deposited cDNA or the nucleotide sequence as shown in SEQ ID NO: l . In this context "about includes the particularly recited size, larger or smaller by several (5, 4, 3, 2, or 1) nucleotides, at either terminus or at both termini. Representative examples of TRID polynucleotide fragments of the invention include, for example, fragments that comprise, or alternatively, consist of, a sequence from about nucleotide 1 to 50, 51 to 100, 101 to 150, 151 to 182, 183 to 260, 261 to 300, 301 to 350, 351 to 400, 401 to 450, 451 to 500, 501 to 550, 551 to 600, 600 to 650, 651 to 700, 701 to 750, 751 to 800, 800 to 850, 851 to 902, 903 to 959, 960 to 1000, 1001 to 1050, 1051 to 1100, 1 101 to 1 150, 1 151 to 1200, 1201 to 1250, 1251 to 1300, 1301 to 1350, and/or 1351 to 1392, of SEQ ID NO: 1 , or the complementary strand thereto, or the cDNA contained in the deposited clone. In this context "about" includes the particularly recited ranges, larger or smaller by several (5, 4, 3, 2, or 1 ) nucleotides, at either terminus or at both termini. Preferably, the polynucleotide fragments of the invention encode a polypeptide which demonstrates a TRID functional activity. By a polypeptide demonstrating a TRID "functional activity" is meant, a polypeptide capable of displaying one or more known functional activities associated with a full-length (complete) TRID protein. Such functional activities include, but are not limited to, biological activity (e.g., binding TRAIL), antigenicity [ability to bind (or compete with a TRID polypeptide for binding) to an anti-TRID antibody], immunogenicity (ability to generate antibody which binds to a TRID polypeptide), ability to form multimers with TRID polypeptides of the invention, and ability to bind to a receptor or ligand for a TRID polypeptide (e.g., TRAIL). The functional activity of TRID polypeptides, and fragments, variants derivatives, and analogs thereof, can be assayed by various methods. For example, in one embodiment where one is assaying for the ability to bind or compete with full-length TRID polypeptide for binding to anti-TRID antibody, various immunoassays known in the art can be used, including but not limited to, competitive and non-competitive assay systems using techniques such as radioimmunoassays, ELISA (enzyme linked immunosorbent assay), "sandwich" immunoassays, immunoradiometric assays, gel diffusion precipitation reactions, immunodiffusion assays, in situ immunoassays (using colloidal gold, enzyme or radioisotope labels, for example), western blots, precipitation reactions, agglutination assays (e.g., gel agglutination assays, hemagglutination assays), complement fixation assays, immunofluorescence assays, protein A assays, and immunoelectrophoresis assays, etc. In one embodiment, antibody binding is detected by detecting a label on the primary antibody . In another embodiment, the primary antibody is detected by detecting binding of a secondary antibody or reagent to the primary antibody. In a further embodiment, the secondary antibody is labeled. Many means are known in the art for detecting binding in an immunoassay and are within the scope of the present invention. In another embodiment, where a TRID ligand is identified (e.g, TRAIL), or the ability of a polypeptide fragment, variant or derivative of the invention to multimerize is being evaluated, binding can be assayed, e.g. , by means well-known in the art, such as, for example, reducing and non-reducing gel chromatography, protein affinity chromatography, and affinity blotting. See generally, Phizicky, E., et al, Microbiol Rev. 59:94-123 (1995). In another embodiment, physiological correlates of TRID binding to its substrates (signal transduction) can be assayed. In addition, assays described herein (see e.g. ^Examples 5 and 6, and those otherwise known in the art may routinely be applied to measure the ability of TRID polypeptides and fragments, variants derivatives and analogs thereof to elicit TRID related biological activity (e.g. , to block TRAIL induced apoptosis in vitro or in vivo). Other methods will be known to the skilled artisan and are within the scope of the invention. Preferred nucleic acid fragments of the present invention include nucleic acid molecules encoding: epitope-bearing portions of the TRID polypeptide as identified in Figure 3 and described in more detail below. In particular, the invention provides polynucleotides having a nucleotide sequence representing the portion of SEQ ID NO: l, which consist of positions 183-959 of SEQ ID NO:l . Also contemplated are polynucleotides encoding TRID polypeptides which lack an amino terminal methionine. One such preferred polynucleotide of the invention encodes a full-length TRID polypeptide lacking the nucleotides encoding the amino-terminal methionine (e.g. , nucleotides 186-959 in SEQ ID NO: 1 ) as it is known that the methionine is cleaved naturally and such sequences maybe useful in genetically engineering TRID expression vectors. Polypeptides encoded by such polynucleotides are also, provided, such as polypeptides comprising, or alternatively consisting of, an amino acid sequence at positions 2-259 of SEQ ID NO:2, or the polypeptide sequence encoded by the clone deposited with the ATCC as Deposit No. 97798 lacking an amino terminal methionine. Preferred nucleic acid fragments of the present invention include nucleic acid molecules encoding a member selected from the group: a polypeptide comprising, or alternatively consisting of, the TRID extracellular domain (amino acid residues from about 27 to about 240 in SEQ ID NO:2); a polypeptide comprising or alternatively consisting of, the TRID cysteine rich domain (amino acid residues from about 53 to about 150 in SEQ ID NO:2); a polypeptide comprising, or alternatively consisting of, the TRID transmembrane domain (amino acid residues from about 241 to about 259 in SEQ ID NO:2); and a polypeptide comprising, or alternatively consisting of, one, two, three, four or more, epitope bearing portions of the TRID receptor protein. In additional embodiments, the polynucleotide fragments of the invention encode a polypeptide comprising, or alternatively consisting of, any combination of 1, 2, 3, 4, or all 5 of the above-encoded polypeptide embodiments. Since the location of these domains have been predicted by computer graphics, one of ordinary skill would appreciate that the amino acid residues constituting these domains may vary slightly (e.g., by about 1 to 15 residues) depending on the criteria used to define each domain. It is believed one or both of the extracellular cysteine rich motifs of TRID disclosed in Figures 1A-B is important for interactions between TRID and its ligands (e.g., TRAIL). Accordingly, specific embodiments of the invention are directed to polynucleotides encoding polypeptides which comprise, or alternatively consist of, the amino acid sequence of amino acid residues 53 to 110, and/or 11 1 to 150 of SEQ ID NO:2, as disclosed in Figures 1A-B. In a specific embodiment the polynucleotides encoding TRID polypeptides of the invention comprise, or alternatively consist of both of the extracellular cysteine rich motifs disclosed in Figures 1A-B. Polypeptides encoded by these polynucleotides are also encompassed by the invention. In additional embodiments, the polynucleotides of the invention encode functional attributes of TRID. Preferred embodiments of the invention in this regard include fragments that comprise alpha-helix and alpha-helix forming regions ("alpha-regions"), beta-sheet and beta-sheet forming regions ("beta-regions"), turn and turn-forming regions ("turn-regions"), coil and coil-forming regions ("coil-regions"), hydrophilic regions, hydrophobic regions, alpha amphipathic regions, beta amphipathic regions, flexible regions, surface-forming regions and high antigenic index regions of TRID. The data representing the structural or functional attributes of TRID set forth in Figure 3 and/or Table I, as described above, was generated using the various modules and algorithms of the DNA* STAR set on default parameters. In a preferred embodiment, the data presented in columns VIII, IX, XIII, and XIV of Table I can be used to determine regions of TRID which exhibit a high degree of potential for antigenicity . Regions of high antigenicity are determined from the data presented in columns VIII, IX, XIII, and/or XIV by choosing values which represent regions of the polypeptide which are likely to be exposed on the surface of the polypeptide in an environment in which antigen recognition may occur in the process of initiation of an immune response. Certain preferred regions in these regards are set out in Figure 3, but may, as shown in Table I, be represented or identified by using tabular representations of the data presented in Figure 3. The DNA* STAR computer algorithm used to generate Figure 3 (set on the original default parameters) was used to present the data in Figure 3 in a tabular format (See Table I). The tabular format of the data in Figure 3 may be used to easily determine specific boundaries of a preferred region. The above-mentioned preferred regions set out in FIG. 3 and in Table I include, but are not limited to, regions of the aforementioned types identified by analysis of the amino acid sequence set out in SEQ ID NO:2. As set out in FIG. 3 and in Table I, such preferred regions include Garnier-Robson alpha-regions, beta-regions, turn-regions, and coil-regions (columns I, III, V, and VII in Table I), Chou-Fasman alpha-regions, beta-regions, and turn-regions (columns II, IV, and VI in Table I), Kyte-Doolittle hydrophilic regions (column VIII in Table I), Hopp- Woods hydrophobic regions (column IX in Table I), Eisenberg alpha- and beta-amphipathic regions (columns X and XI in Table I), Karplus-Schulz flexible regions (column XII in Table I), Jameson- Wolf regions of high antigenic index (column XIII in Table I), and Emini surface-forming regions (column XIV in Table I). Among highly preferred polynucleotides in this regard are those that encode polypeptides comprising, or alternatively consisting of, regions of TRID that combine several structural features, such as several (e.g.. 1, 2, 3, or 4) of the same or different region features set out above. Table I Res Position I II in rv v vι vπ viπ IX λ XI XII xπi xrv Met 1 A -0 23 0 09 * * -0 10 0 51 Aig A 0 28 -0 34 * * 0 50 0 97 He 4 A -0 14 -0 29 * * 0 65 1 42 Pro 5 A 0 29 -0 21 * * F 0 80 1 16 s 6 A 0 19 -0 71 * * F 1 10 1 18 Thr 7 A B -0 08 0 07 * * r 0 00 1 46 Leu 8 A B -1 04 0 03 * * F -0 15 0 70 Lvs 9 A B -1 01 0 24 * * -0 30 0 26 Phe 10 A B -1 69 0 89 * * -0 60 0 13 Val 1 1 B B -2 59 1 09 * * -0 60 0 1 1 Val 12 B B -2 87 1 04 * * -0 60 0 04 Vdl n B B -2 91 1 54 * * -0 60 0 05 He 14 B B -3 77 1 40 * * -0 60 0 05 Vdl 15 A B -3 88 1 44 -0 60 0 05 Ala 16 A B -3 23 1 49 -0 60 0 06 Vdl 17 A B -3 23 1 27 -0 60 0 1 Leu 18 A B -3 19 1 23 -0 60 0 1 Leu 19 B B -2 89 1 27 * -0 60 0 1 1 Pro 20 A B -2 28 1 27 -0 60 0 15 Vdl 21 A B -1 99 1 39 -0 60 0 28 Leu 22 A B -1 72 1 09 -0 60 0 46 Aid 23 A B -1 22 0 90 * -0 60 0 30 Tyr 24 A B -0 72 0 96 -0 60 0 58 Ser 25 A B -1 10 0 80 * * -0 45 1 02 Aid 26 A B -0 13 0 61 * -0 45 1 02 Thi 27 A B 0 68 0 1 1 * F 0 00 1 28 Thr 28 A A B 1 27 -0 24 * F -0 60 1 65 Ala 29 A A B 1 51 -0 63 F 0 90 2 83 Arg 30 A A B 0 96 -1 13 F 0 90 3 40 Gin 31 A A B 1 33 -0 97 F 0 90 1 75 Glu 32 A A B 1 64 -1 03 F 0 90 2 68 Glu 33 A A 1 96 -1 13 * F 0 90 2 37 Vdl 34 A C 2 23 -0 73 * F 1 10 2 37 Pro 35 A T 1 27 -0 64 * F 1 30 1 97 Gin 36 B T 0 68 -0 00 F 0 85 0 85 Table I (continued) Res Position I II 1-3 IV V VI vπ viπ IX X XI XII xπi XIV Gin 37 B C 047 050 r -010 1 15 Thi 38 B C 047 029 F 020 1 15 Aid 40 B C 153 026 * * Γ 020 1 15 Pro 41 A B 164 026 * F 000 138 Gin 42 A 161 -023 * r 1 14 364 Gin 43 A 162 -037 * * F 148 491 Gin 44 A T 178 -049 * * F 202 425 Arg 45 T T 241 -013 * * Γ 276 213 His 46 T T 228 -053 * * Γ 340 246 Ser 47 T C 228 -050 * * 271 140 Phe 48 A T 228 -090 * * F 232 124 L\s 49 A T 161 -090 * * F 198 138 Glv 50 A T 129 -083 * * F 149 063 Glu 51 A T 073 -079 * r 130 1 13 Glu 52 A A 069 -107 * Γ 075 057 Cys 53 A T 109 064 * F 1 15 057 Pro 54 A T 101 -069 * * r 1 15 044 Aid 55 A T 147 -019 * * 1 083 033 Gl\ 56 A T 1 17 -019 * F 100 127 Ser 57 A 1 17 -037 * F 080 110 His 58 A 180 -080 * F 144 188 Arg 59 A 170 -080 * F 178 259 Ser 60 T 194 -074 * F 252 278 Glu 61 T 170 -070 * F 286 203 His 62 T T 133 -070 * * F 340 104 Thr 63 T T 137 -013 * * F 261 042 Glv 64 T T 104 -011 * * 212 039 C\s 66 T 037 039 064 016 Asn 67 T C 040 039 030 024 Pro 68 T T 037 -004 * F 153 041 Cys 69 T T -014 -011 * F 181 076 Thr 70 T T 044 -004 * F 209 035 Glu 71 087 -044 * F 177 038 Gl\ 72 T T 056 -011 * F 280 1 10 Table I (continued) Res Position I II in rv V VI vπ vm IX X XI XII xπi xrv Vdl 73 B T 077 -020 F 212 1 10 Asp 74 B T 084 -029 169 102 T\r 75 T c 086 021 101 104 Tin 76 c 086 017 F 068 188 Asn 77 c 120 -007 F 134 181 Ser 79 T T 184 -043 F 242 224 Asn 80 T T 179 -049 F 276 215 Asn 81 T T 143 -050 F 340 285 Glu 82 T c 073 -043 F 256 1 14 Pro 83 T T 111 -003 F 227 061 Ser 84 T T 074 -000 F 193 059 Cys 85 T T 043 017 084 018 Phe 86 T -042 066 -020 017 Pro 87 T T -109 087 020 009 C\ 88 T 1 -083 106 020 009 Thr 89 A T -083 049 -020 022 Cvs 91 A T 053 -034 070 059 Lvs 92 A T 079 -051 F 1 15 071 Ser 93 A T 142 -100 F 164 190 Asp 94 A T 178 -114 F 198 484 Gin 95 A 233 -171 F 212 484 Lvs 96 T 270 -133 F 286 484 His 97 T T 199 -133 F 340 388 Lys 98 T T 198 -076 F 306 120 Ser 99 T T 138 -067 F 257 087 Ser 100 T T 107 -006 F " 193 063 C S 101 B T 113 -007 F 1 19 045 Thr 102 B T 117 -007 070 066 Met 103 B T 081 -046 070 083 Thr 104 T T -011 -029 F 140 115 Asp 106 T T 056 -020 F 125 062 Thr 107 A T 020 -041 070 075 Vdl 108 A B 084 -033 064 020 Cvs 109 A B 116 -033 098 024 Table I (continued) Res Position I II in IV V vi vπ vπi ix x xi xπ xπi xrv Gin 110 B T 070 -033 172 029 Cvs 111 I T 039 -039 246 039 L S 112 T T -000 -054 F 340 105 Glu 113 T T 097 -033 F 261 053 Gl\ 114 T T 163 -073 F 306 192 Thr 115 T 163 -090 r 286 155 Phe 116 C 230 -090 F 266 155 Arg 117 T 196 -050 F 286 251 Asn 118 T T 174 -054 F 340 233 Glu 119 T T 209 -060 F 306 417 Asn 120 T C 180 -139 F 252 368 Ser 121 T C 183 -077 F 218 227 Pro 122 T 183 -060 F 169 070 Glu 123 A 188 -060 F 126 085 Met 124 A 121 -100 157 128 Cvs 125 A T 091 -081 193 044 Arg 126 T T 132 -086 264 034 L^s 127 T T 087 -086 F 310 068 Cys 128 T T 066 -090 F 279 068 Ser 129 T 096 -104 F 239 053 Arg 130 T 128 -066 F 259 036 C 131 T C 117 -023 F 229 066 Pro 132 T T 027 -080 F 279 085 Ser 133 T T 093 -054 F 310 032 Gly 134 T T 038 -014 F 264 105 Glu 135 B T -003 -007 F 178 050 Val 136 B B 063 -011 F 107 050 Gin 137 B B 018 -010 961 082 Ser 139 T T 021 053 020 049 Asn 140 T T -008 027 F 065 038 CtS 141 T T 078 079 F 063 054 Thr 142 T 078 014 F 101 067 Ser 143 T 074 -024 F 189 070 Trp 144 T T 104 004 F 177 091 Asp 145 T T 038 -013 F 280 109 Asp 146 T T 019 -004 F 237 044 Table I (continued) Res Position I 11 HI IV V VI Vπ VIII IX X XI XU He 147 A T 0 50 0 21 Gin 148 Λ A 0 80 -0 70 C\ s 149 A 0 39 -0 70 Glu 151 A A -0 54 -0 17 Glu 152 A A 0 34 -0 07 Phe 153 A A -0 24 -0 24 Asn 156 A T 0 1 1 0 74 Thr 158 A A 0 29 0 01 Glu 160 A A 0 04 0 04 F Thr 161 A A 0 04 0 04 F Pro 162 A A 0 63 -0 44 F Glu 165 A A 0 89 -0 47 F Glu 166 A A 0 89 -0 50 r Thr 167 A A 0 80 -0 51 F Met 168 A T 1 18 -0 63 F Asn 169 A T 1 42 -0 20 F Thr 170 A C 1 11 0 23 F Ser 171 T c 0 90 0 23 F Pro 172 T T 0 62 0 04 F Thr 174 T c 0 42 0 09 F Pro 175 c 0 14 0 20 F Ala 176 A c 0 44 0 27 F Pro 177 A A 0 66 -0 16 Glu 180 A A 0 61 -0 47 Glu 181 A A 0 89 -0 50 Thr 182 A A 0 80 -0 51 Met 183 A T 1 18 -0 63 Table I (continued) Res Position 1 ii in rv v VI vπ viπ rx x XI XII xm xrv Asn 184 A T 142 -020 * 100 157 Thi 185 A c 1 11 023 F 020 108 Sei 186 I c 090 023 F 060 137 Pio 187 T T 062 004 r 080 151 Gl\ 188 T c 101 014 Γ 060 106 Tin 189 T c 042 009 Γ 060 122 Pi 190 c 014 020 Γ 025 080 Aid 191 A c 044 027 F 005 082 Pio 192 A A 066 -016 030 098 Aid 193 A A 069 -064 075 1 10 Aid 1 4 A A 040 -059 075 157 Glu 195 A A 030 -047 F 060 100 Glu 196 A A 058 -041 r 060 143 Thr 197 A A 049 -043 F 060 205 Met 198 A A 087 -054 r 106 158 Tin 199 A T 1 11 -011 F 132 141 Tin 200 A c 080 031 r 053 097 Sei 201 T c 059 031 Γ 124 141 Pro 202 T T 031 013 Γ 160 151 Gh 203 T c 070 014 F 124 106 Tin 204 T c 042 009 r 108 122 Pio 205 c 014 020 F 057 080 Aid 206 A c 044 027 F 021 082 Pio 207 A A 066 -016 030 098 Aid 208 A A 069 -064 075 1 10 Aid 209 A A 040 -059 075 157 Glu 210 A A 030 -047 F 060 100 Glu 211 A A 058 -041 F 060 143 Tin 212 A A 049 -043 F 060 205 Met 213 A A 087 -054 F 106 158 Tin 214 A T 111 -011 r 132 141 Thr 215 A c 080 031 F 053 097 Ser 216 T c 059 031 F 124 141 Pro 217 T T 031 013 F 160 151 Gh 218 T c 070 014 F 124 106 Thr 219 T c 042 009 F 108 122 Pro 220 c 014 020 F 057 080 Table I (continued) Res Position I II HnI rv V VI vπ viπ IX X XI XII xπi XIV Aid 221 A c 044 027 F 021 082 Pro 222 A A 066 -016 030 098 Aid 223 A A 069 -064 073 1 10 Aid 224 A A 040 -059 073 157 Glu 223 A A 030 -047 F 060 100 Glu 226 A A 058 -041 r 060 143 Thr 227 A A 049 -043 1 072 205 Met 228 A A 087 -054 F 1 14 158 Thr 229 A T 1 11 -011 r 136 141 Thr 230 A c 080 031 F 053 097 Ser 231 T c 059 031 F 120 141 Pio 232 T c 031 013 F 108 151 Gh 233 T c 061 014 F 096 106 Thr 234 T c 062 004 F 084 106 Pro 235 c 090 004 r 037 092 Sei 237 T T 036 044 F 050 137 Ser 238 T T 040 064 020 073 TM 240 T T -006 067 * 020 039 Leu 241 B T -036 077 020 042 Ser 242 B T -091 107 -020 022 C\ s 243 B B -096 121 * -060 010 Tin 244 B B -181 089 * -060 012 He 245 B B -246 089 -060 006 Vdl 246 B B -250 1 19 * -060 008 Gh 247 B B -301 126 -060 004 He 248 B B -323 146 * 06) 005 He 249 B B -378 146 -060 005 Vdl 250 B B -370 146 -060 004 Leu 251 B B -366 171 060 004 He 252 B B -420 171 -060 00s Vdl 253 B B -417 171 -060 003 Leu 254 B B -398 171 -060 004 Leu 255 A B -398 181 -060 005 He 256 A B -356 177 -060 005 Vdl 257 B B -306 156 -060 008 Tablc 1 (continued) Res Position I II IH IV V VI VH VIH IX X XI XII XHI XIV Phe 238 A B 259 130 -060 013 Vdl 259 A B -217 104 060 023 Among highly preferred fragments in this regard are those that comprise, or alternatively consist of, regions of the TRID protein that combine several structural features, such as several of the features set out abo\ e Preferred nucleic acid fragments of the present invention further include nucleic acid molecules encoding a polypeptide comprising, or alternatively consisting of, one, two, three, four, five, or more epitope-beanng portions of the TRID protein In particular, such nucleic In this context "about" mcludes the particularly recited size, larger or smaller by several (5, 4, 3, 2 or 1) nucleotides, at either terminus or at both termini acid fragments of the present invention include nucleic acid molecules encoding a polypeptide compπsing, or alternatively consisting of, amino acid residues from about Gln-42 to about Glu-52 in SEQ ID NO 2, a polypeptide comprising, or alternatively consisting of, amino acid residues from aboutHιs-58 to about Cys-66 in SEQ ID NO 2, a polypeptide compπsing, or alternatively consisting of, amino acid residues from about Pro-68 to about Thr-76 in SEQ ID NO 2, a polypeptide comprising, or alternatively consisting of, ammo acid residues from about Ser-79 to about Cys-85 in SEQ ID NO 2, a polypeptide comprising, or alternatively consisting of, amino acid residues from about Cys-91 to about Thr- 102 in SEQ ID NO 2, a polypeptide compπsing, or alternatively consisting of amino acid residues from about Gln-110 to about Pro-122 in SEQ ID NO 2, a polypeptide comprising, or alternatively consisting of, amino acid residues from about Arg-126 to about Val-136 in SEQ ID NO 2, and a polypeptide comprising, or alternatively consisting of, ammo acid residues from about Thr- 142 to about Gln-148 in SEQ ID NO 2 The inventors have determined that the above polypeptide fragments are antigenic regions of the TRID protein Methods for determining other such epitope-beanng portions of the TRID protein are described in detail below In specific embodiments, the polynucleotides of the invention are less than 100000 kb, 50000 kb, 10000 kb, 1000 kb, 500 kb, 400 kb, 350 kb, 300 kb, 250 kb, 200 kb, 175 kb, 150 kb, 125 kb, 100 kb, 75 kb, 50 kb, 40 kb, 30 kb, 25 kb, 20 kb, 15 kb, 10 kb, 7.5 kb, or 5 kb in length. In further embodiments, polynucleotides of the invention comprise, or alternatively consist of, at least 15, at least 30, at least 50, at least 100, or at least 250, at least 500, or at least 1000 contiguous nucleotides of TRID coding sequence, but consist of less than or equal to 1000 kb, 500 kb, 250 kb, 200 kb, 150 kb, 100 kb, 75 kb, 50 kb, 30 kb, 25 kb, 20 kb, 15 kb, 10 kb, or 5 kb of genomic DNA that flanks the 5' or 3' coding nucleotide set forth in Figures 1 A-D (SEQ ID NO:l). In further embodiments, polynucleotides of the invention comprise, or alternatively consist of, at least 15, at least 30, at least 50, at least 100, or at least 250, at least 500, or at least 1000 contiguous nucleotides of TRID coding sequence, but do not comprise all or a portion of any TRID intron. In another embodiment, the nucleic acid comprising, or alternatively consisting of, TRID coding sequence does not contain coding sequences of a genomic flanking gene (i.e., 5' or 3' to the TRID gene in the genome). In other embodiments, the polynucleotides of the invention do not contain the coding sequence of more than 1000, 500, 250, 100, 50, 25, 20, 15, 10, 5, 4, 3, 2, or 1 genomic flanking gene(s). Further, the invention includes a polynucleotide comprising, or alternatively consisting of, any portion of at least about 30 nucleotides, preferably at least about 50 nucleotides, of SEQ ID NO: 1 from residue 183 to 959. In this context "about" includes the particularly recited size, larger or smaller by several (5, 4, 3, 2, or 1) nucleotides, at either terminus or at both termini. In another aspect, the invention provides an isolated nucleic acid molecule comprising, or alternatively consisting of, a polynucleotide which hybridizes under stringent hybridization conditions to a portion of the polynucleotide in a nucleic acid molecule of the invention described above, for instance, a cDNA clone contained in ATCC Deposit No. 97798. By "stringent hybridization conditions" is intended overnight incubation at 42° C in a solution comprising, or alternatively consisting of,: 50% formamide, 5x SSC (750 mM NaCl, 75 mMtrisodium citrate), 50 mM sodium phosphate (pH 7.6), 5x Denhardt's solution, 10% dextran sulfate, and 20 μg/ml denatured, sheared salmon sperm DNA, followed by washing the filters in O.lx SSC at about 65° C. Polypeptides encoded by these nucleic acid molecules are also encompassed by the invention. In another aspect, the invention provides an isolated nucleic acid molecule comprising, or alternatively consisting of, a polynucleotide which hybridizes under lower stringency conditions to a portion of the polynucleotide in a nucleic acid molecule of the invention described above, for instance, a cDNA clone contained in ATCC Deposit No. 97798. By "lower stringency conditions" is intended overnight incubation at 35° C or 42° C in a solution comprising, or alternatively consisting of: 50% formamide, 5x SSC (750 mM NaCl, 75 mM trisodium citrate), 50 mM sodium phosphate (pH 7.6), 5x Denhardt's solution, 10% dextran sulfate, and 20 μg/ml denatured, sheared salmon sperm DNA, followed by washing the filters in 3x, 2x, lx, or 0.5x SSC at about 35° C, 45° C, 55° C, or 65° C. Polypeptides encoded by these nucleic acid molecules are also encompassed by the invention. By a polynucleotide which hybridizes to a "portion" of a polynucleotide is intended a polynucleotide (either DNA or RNA) hybridizing to at least about 15 nucleotides (nt), and more preferably at least about 20 nt, still more preferably at least about 30 nt, and even more preferably about 30-70 (e.g., 50) nt of the reference polynucleotide. In this context "about" includes the particularly recited size, larger or smaller by several (5, 4, 3, 2, or 1) nucleotides, at either terminus or at both termini. These have uses, which include, but are not limited to, as diagnostic probes and primers as discussed above and in more detail below. By a portion of a polynucleotide of "at least 20 nt in length ' for example, is intended 20 or more contiguous nucleotides from the nucleotide sequence of the reference polynucleotide (e.g., a deposited cDNA or the nucleotide sequence as shown in SEQ ID NO:l). Of course, a polynucleotide which hybridizes only to a poly A sequence (such as the 3' terminal poly(A) tract of the TRID cDNA shown in SEQ ID NO:l), or to a complementary stretch of T (or U) residues, would not be included in a polynucleotide of the invention used to hybridize to a portion of a nucleic acid of the invention, since such a polynucleotide would hybridize to any nucleic acid molecule containing a poly (A) stretch or the complement thereof (e.g., practically any double-stranded cDNA clone). As indicated, nucleic acid molecules of the present invention which encode a TRID polypeptide may include, but are not limited to the coding sequence for the mature polypeptide, by itself; the coding sequence for the mature polypeptide and additional sequences, such as those encoding a leader or secretary sequence, such as a pre-, or pro- or prepro- protein sequence; the coding sequence of the mature polypeptide, with or without the aforementioned additional coding sequences, together with additional, non-coding sequences, including for example, but not limited to introns and non-coding 5' and 3' sequences, such as the transcribed, non-translated sequences that play a role in transcription, mRNA processing - including splicing and polyadenylation signals, for example - ribosome binding and stability of mRNA; additional coding sequence which codes for additional amino acids, such as those which provide additional functionalities. Thus, for instance, the polypeptide may be fused to a marker sequence, such as a peptide, which facilitates purification of the fused polypeptide. In certain preferred embodiments of this aspect of the invention, the marker sequence is a hexa-histidine peptide, such as the tag provided in a pQE vector (Qiagen, Inc.), among others, many of which are commercially available. As described in Gentz et al, Proc. Natl. Acad. Sci. USA 86: 821-824 (1989), for instance, hexa- histidine provides for convenient purification of the fusion protein. The "HA" tag is another peptide useful for purification which corresponds to an epitope derived from the influenza hemagglutinin protein, which has been described by Wilson et al, Cell 57:767-778(1984). As discussed below, other such fusion proteins include the TRID receptor fused to Fc at the N- or C- terminus. Variant and Mutant Polynucleotides The present invention further relates to variants of the nucleic acid molecules of the present invention, which encode portions, analogs, or derivatives of the TRID receptor. Variants may occur naturally, such as a natural allelic variant. By an "allelic variant" is intended one of several alternate forms of a gene occupying a given locus on a chromosome of an organism. Genes II, Lewin, B., ed., John Wiley & Sons, New York (1985). Non-naturally occurring variants may be produced using art-known mutagenesis techniques. Such variants include those produced by nucleotide substitutions, deletions or additions. The substitutions, deletions or additions may involve one or more nucleotides. The variants may be altered in coding regions, non-coding regions, or both. Alterations in the coding regions may produce conservative or non-conservative amino acid substitutions, deletions or additions. Especially preferred among these are silent substitutions, additions and deletions, which do not alter the properties and activities of the TRID polypeptide or portions thereof. Also especially preferred in this regard are conservative substitutions. Further embodiments of the invention include an isolated nucleic acid molecule comprising, or alternatively consisting of, a polynucleotide having a nucleotide sequence at least 90% identical, and more preferably at least 95%, 96%, 97%, 98% or 99% identical to: (a) a nucleotide sequence encoding the polypeptide having the amino acid sequence in SEQ ID NO:2; (b) a nucleotide sequence encoding the polypeptide having the amino acid sequence in SEQ ID NO:2, but lacking the amino terminal methionine; (c) a nucleotide sequence encoding the polypeptide having the amino acid sequence at positions from about 1 to about 259 in SEQ ID NO:2; (d) a nucleotide sequence encoding the polypeptide having the amino acid sequence encoded by the cDNA clone contained in ATCC Deposit No. 97798; (e) a nucleotide sequence encoding the mature TRID polypeptide having the amino acid sequence at positions from about 27 to about 259 in SEQ ID NO:2; (f) a nucleotide sequence encoding the mature TRID polypeptide having the amino acid sequence encoded by the cDNA clone contained in ATCC Deposit No. 97798; (g) a nucleotide sequence encoding the TRID extracellular domain having the amino acid sequence at positions from about 27 to about 240 in SEQ ID NO:2; (h) a nucleotide sequence that encoding the TRID extracellular domain having the amino acid sequence encoded by the cDNA contained in ATCC Deposit No. 97798; (i) a nucleotide sequence encoding the TRID cysteine rich domain having the amino acid sequence at positions from about 53 to about 150 in SEQ ID NO:2; (j) a nucleotide sequence encoding the TRID cysteine rich domain having the amino acid sequence encoded by the cDNA contained in ATCC Deposit No. 97798; (k) a nucleotide sequence encoding the TRID transmembrane domain having the amino acid sequence at positions from about 241 to about 259 of SEQ ID NO:2; (1) a nucleotide sequence encoding the TRID transmembrane domain having the amino acid sequence encoded by the cDNA contained in ATCC Deposit No. 97798;(m) a nucleotide sequence that encodes a fragment of the polypeptide of (e) or (f) having TRID functional activity (e.g., antigenic or biological activity); and (n) a nucleotide sequence complementary to any of the nucleotide sequences in (a), (b), (c), (d), (e), (f), (g), (h), (i), (j), (k), (1) or (m) above. Also contemplated are polypeptides encoded by the nucleotide sequences in (a), (b), (c), (d), (e), (f), (g), (h), (i), (j), (k), (1) or (m) above. In this context "about" includes the particularly recited size, larger or smaller by several (5, 4, 3, 2 or 1) nucleotides, at either terminus or at both termini. Further embodiments of the invention include isolated nucleic acid molecules that comprise, or alternatively consist of, a polynucleotide which hybridizes under stringent hybridization conditions to a polynucleotide in (a), (b), (c), (d), (e), (f), (g), (h), (i), (j), (k), (1) or (m) above. This polynucleotide which hybridizes does not hybridize under stringent hybridization conditions to a polynucleotide having a nucleotide sequence consisting of only A residues or of only T residues. An additional nucleic acid embodiment of the invention relates to an isolated nucleic acid molecule comprising, or alternatively consisting of, a polynucleotide which encodes the amino acid sequence of an epitope-bearing portion of a TRID polypeptide having an amino acid sequence in (a), (b), (c), (d), (e), (f), (g), (h), (i), 0), (k), (1) or (m) above. By a polynucleotide having a nucleotide sequence at least, for example, 95% "identical" to a reference nucleotide sequence encoding a TRID polypeptide is intended that the nucleotide sequence of the polynucleotide is identical to the reference sequence except that the polynucleotide sequence may include up to five mismatches per each 100 nucleotides of the reference nucleotide sequence encoding the TRID polypeptide. In other words, to obtain a polynucleotide having a nucleotide sequence at least 95% identical to a reference nucleotide sequence, up to 5% of the nucleotides in the reference sequence may be deleted or substituted with another nucleotide, or a number of nucleotides up to 5% of the total nucleotides in the reference sequence may be inserted into the reference sequence. These mutations of the reference sequence may occur at the 5' or 3' terminal positions of the reference nucleotide sequence or anywhere between those terminal positions, interspersed either individually among nucleotides in the reference sequence or in one or more contiguous groups within the reference sequence. The reference (query) sequence may be the entire TRID encoding nucleotide sequence shown in SEQ ID NO: l or any TRID polynucleotide fragment (e.g. , a polynucleotide encoding the amino acid sequence of any of the TRID N- and/or C- terminal deletions described herein), variant, derivative or analog, as described herein. As a practical matter, whether any particular nucleic acid molecule is at least 90%, 95%, 96%, 97%, 98% or 99% identical to, for instance, the nucleotide sequence shown in SEQ ID NO: 1 , or to the nucleotide sequence of the deposited cDNA clone can be determined conventionally using known computer programs such as the Bestfit program (Wisconsin Sequence Analysis Package, Version 8 for Unix, Genetics Computer Group, University Research Park, 575 Science Drive, Madison, WI 53711). Bestfit uses the local homology algorithm of Smith and Waterman, Advances in Applied Mathematics 2:482-489 (1981), to find the best segment of homology between two sequences. When using Bestfit or any other sequence alignment program to determine whether a particular sequence is, for instance, 95% identical to areference sequence according to the present invention, the parameters are set, of course, such that the percentage of identity is calculated over the full length of the reference nucleotide sequence and that gaps in homology of up to 5% of the total number of nucleotides in the reference sequence are allowed. In a specific embodiment, the identity between a reference (query) sequence (a sequence of the present invention) and a subject sequence, also referred to as a global sequence alignment, is determined using the FASTDB computer program based on the algorithm of Brutlag et al. (Comp. App. Biosci. 6:231-245 (1990)). Preferred parameters used in a FASTDB alignment of DNA sequences to calculate percent identity are: Matrix=Unitary, k-tuple=4, Mismatch Penalty=l , Joining Penalty=30, Randomization Group Length=0, Cutoff Score=T , Gap Penalty=5, Gap Size Penalty 0.05, Window Size=500 or the length of the subject nucleotide sequence, whichever is shorter. According to this embodiment, if the subject sequence is shorter than the query sequence because of 5' or 3' deletions, not because of internal deletions, a manual correction is made to the results to take into consideration the fact that the FASTDB program does not account for 5' and 3' truncations of the subject sequence when calculating percent identity. For subject sequences truncated at the 5' or 3' ends, relative to the query sequence, the percent identity is corrected by calculating the number of bases of the query sequence that are 5' and 3' of the subject sequence, which are not matched/aligned, as a percent of the total bases of the query sequence. A determination of whether a nucleotide is matched/aligned is determined by results of the FASTDB sequence alignment. This percentage is then subtracted from the percent identity, calculated by the above FASTDB program using the specified parameters, to arrive at a final percent identity score. This corrected score is what is used for the purposes of this embodiment. Only bases outside the 5' and 3' bases of the subject sequence, as displayed by the FASTDB alignment, which are not matched/aligned with the query sequence, are calculated for the purposes of manually adjusting the percent identity score. For example, a 90 base subject sequence is aligned to a 100 base query sequence to determine percent identity. The deletions occur at the 5' end of the subject sequence and therefore, the FASTDB alignment does not show a matched/alignment of the first 10 bases at 5' end. The 10 unpaired bases represent 10% of the sequence (number of bases at the 5' and 3' ends not matched/total number of bases in the query sequence) so 10% is subtracted from the percent identity score calculated by the FASTDB program. If the remaining 90 bases were perfectly matched the final percent identity would be 90%. In another example, a 90 base subject sequence is compared with a 100 base query sequence. This time the deletions are internal deletions so that there are no bases on the 5' or 3' of the subject sequence which are not matched/aligned with the query . In this case the percent identity calculated by FASTDB is not manually corrected. Once again, only bases 5' and 3' of the subject sequence which are not matched/aligned with the query sequence are manually corrected for. No other manual corrections are made for the purposes of this embodiment. The present application is directed to nucleic acid molecules at least 90%, 95%, 96%, 97%, 98% or 99% identical to a nucleic acid sequence shown in SEQ ID NO : 1 , or to the nucleic acid sequence of the deposited cDNA, irrespective of whether they encode a polypeptide having TRID activity. This is because even where a particular nucleic acid molecule does not encode a polypeptide having TRID activity, one of skill in the art would still know how to use the nucleic acid molecule, for instance, as a hybridization probe or a polymerase chain reaction (PCR) primer. Uses of the nucleic acid molecules of the present invention that do not encode a polypeptide having TRID activity include, inter alia: (1 ) isolating a TRID gene or allelic variants thereof in a cDNA library; (2) in situ hybridization (e.g., "FISH") to metaphase chromosomal spreads to provide precise chromosomal location of the TRID gene, as described in Verma et al., Human Chromosomes: A Manual of Basic Techniques, Pergamon Press, New York (1988); and Northern Blot analysis for detecting TRID mRNA expression in specific tissues. Preferred, however, are nucleic acid molecules having sequences at least 90%, 95%, 96%, 97%, 98% or 99% identical to a nucleic acid sequence shown in SEQ ID NO: l, or to the nucleic acid sequence of the deposited cDNA which does, in fact, encode a polypeptide having TRID receptor activity. By "a polypeptide having TRID receptor activity" is intended polypeptides exhibiting activity similar, but not necessarily identical, to an activity of the TRID receptor of the invention (either the full length protein or preferably the mature protein or extracellular domain alone), as measured in aparticular biological assay. The TNF family ligands (including TRAIL) induce various cellular responses by binding to TNF-family receptors, including the TRID of the present invention. Cells which express TRID are believed to have a potent cellular response to ligands including TRAIL. By a "cellular response to a TNF-family ligand" is intended any genotypic, phenotypic, and/or morphological change to a cell, cell line, tissue, tissue culture or patient that is induced by a TNF-family ligand. As indicated, such cellular responses include not only normal physiological responses to TNF-family ligands, but also diseases associated with increased cell proliferation or the inhibition of increased cell proliferation, such as by the inhibition of apoptosis. Of course, due to the degeneracy of the genetic code, one of ordinary skill in the art will immediately recognize that a large number of the nucleic acid molecules having a sequence at least 90%, 95%, 96%, 97%, 98%, or 99% identical to the nucleic acid sequence of a deposited cDNA or the nucleic acid sequence shown in SEQ ID NO: 1 will encode a polypeptide "having TRID protein activity." In fact, since degenerate variants of these nucleotide sequences all encode the same polypeptide, this will be clear to the skilled artisan even without performing the above described comparison assay. It will be further recognized in the art that, for such nucleic acid molecules that are not degenerate variants, a reasonable number will also encode a polypeptide having TRID protein activity. This is because the skilled artisan is fully aware of amino acid substitutions that are either less likely or not likely to significantly effect protein function (e.g. , replacing one aliphatic amino acid with a second aliphatic amino acid), as further described below. For example, guidance concerning how to make phenotypically silent amino acid substitutions is provided in Bowie et al., "Deciphering the Message in Protein Sequences: Tolerance to Amino Acid Substitutions ' Science 247:1306- 1310 (1990), wherein the authors indicate that proteins are surprisingly tolerant of amino acid substitutions. Polynucleotide Assays This invention is also related to the use of the TRID polynucleotides to detect complementary polynucleotides such as, for example, as a diagnostic reagent. Detection of a mutated form of TRID associated with a dysfunction will provide a diagnostic tool that can add or define a diagnosis of a disease or susceptibility to a disease which results from under-expression over-expression or altered expression of TRID or a soluble form thereof, such as, for example, tumors or autoimmune disease. Individuals carrying mutations in the TRID gene may be detected at the DNA level by a variety of techniques. Nucleic acids for diagnosis may be obtained from a patient's cells, such as from blood, urine, saliva, tissue biopsy and autopsy material. The genomic DNA may be used directly for detection or may be amplified enzymatically by using PCR prior to analysis. (Saiki et al, Nature J2J: 163-166 (1986)). RNA or cDNA may also be used in the same ways. As an example, PCR primers complementary to the nucleic acid encoding TRID can be used to identify and analyze TRID expression and mutations. For example, deletions and insertions can be detected by a change in size of the amplified product in comparison to the normal genotype. Point mutations can be identified by hybridizing amplified DNA to radiolabeled TRID RNA or alternatively, radiolabeled TRID antisense DNA sequences. Perfectly matched sequences can be distinguished from mismatched duplexes by RNase A digestion or by differences in melting temperatures. Sequence differences between a reference gene and genes having mutations also may be revealed by direct DNA sequencing. In addition, cloned DNA segments may be employed as probes to detect specific DNA segments. The sensitivity of such methods can be greatly enhanced by appropriate use of PCR or another amplification method. For example, a sequencing primer is used with double-stranded PCR product or a single-stranded template molecule generated by a modified PCR. The sequence determination is performed by conventional procedures with radiolabeled nucleotide or by automatic sequencing procedures with fluorescent-tags. Genetic testing based on DNA sequence differences may be achieved by detection of alteration in electrophoretic mobility of DNA fragments in gels, with or without denaturing agents. Small sequence deletions and insertions can be visualized by high resolution gel electrophoresis. DNA fragments of different sequences may be distinguished on denaturing formamide gradient gels in which the mobilities of different DNA fragments are retarded in the gel at different positions according to their specific melting or partial melting temperatures (see. e.g., Myers et al, Science 230: 1242 (1985)). Sequence changes at specific locations also may be revealed by nuclease protection assays, such as RNase and SI protection or the chemical cleavage method (e.g., Cotton et al, Proc. Natl. Acad. Sci. USA 85: 4397-4401 (1985)). Thus, the detection of a specific DNA sequence may be achieved by methods such as hybridization, RNase protection, chemical cleavage, direct DNA sequencing or the use of restriction enzymes, (e.g., restriction fragment length polymorphisms ("RFLP") and Southern blotting of genomic DNA. In addition to more conventional gel-electrophoresis and DNA sequencing, mutations also can be detected by in situ analysis. Vectors and Host Cells The present invention also relates to vectors which include the isolated DNA molecules of the present invention, host cells which are genetically engineered with the recombinant vectors of the invention and the production of TRID polypeptides or fragments thereof by recombinant techniques. Host cells can be genetically engineered to incorporate nucleic acid molecules and express polypeptides of the present invention. The polynucleotides may be introduced alone or with other polynucleotides. Such other polynucleotides may be introduced independently, co-introduced or introduced joined to the polynucleotides of the invention. In accordance with this aspect of the invention the vector may be, for example, a plasmid vector, a single or double-stranded phage vector, a single or double-stranded RNA or DNA viral vector. Such vectors may be introduced into cells as polynucleotides, preferably DNA, by well known techniques for introducing DNA and RNA into cells. Viral vectors may be replication competent or replication defective. In the latter case viral propagation generally will occur only in complementing host cells. Preferred among vectors, in certain respects, are those for expression of polynucleotides and polypeptides of the present invention. Generally, such vectors comprise c/-s"-acting control regions effective for expression in a host operatively linked to the polynucleotide to be expressed. Appropriate trans-acting factors either are supplied by the host, supplied by a complementing vector or supplied by the vector itself upon introduction into the host. A great variety of expression vectors can be used to express a polypeptide of the invention. Such vectors include chromosomal, episomal and virus-derived vectors e.g., vectors derived from bacterial plasmids, from bacteriophage, from yeast episomes, from yeast chromosomal elements, from viruses such as baculoviruses, papova viruses, such as S V40, vaccinia viruses, adenoviruses, fowl pox viruses, pseudorabies viruses and retroviruses, and vectors derived from combinations thereof, such as those derived from plasmid and bacteriophage genetic elements, such as cosmids and phagemids, all may be used for expression in accordance with this aspect of the present invention. Generally, any vector suitable to maintain, propagate or express polynucleotides to express a polypeptide in a host may be used for expression in this regard. The DNA sequence in the expression vector is operatively linked to appropriate expression control sequence(s)), including, for instance, a promoter to direct mRNA transcription. Representatives of such promoters include the phage lambda PL promoter, the E. coli lac, trp and tac promoters, the SV40 early and late promoters and promoters of retroviral LTRs, to name just a few of the well-known promoters. In general, expression constructs will contain sites for transcription, initiation and termination, and, in the transcribed region, a ribosome binding site for translation. The coding portion of the mature transcripts expressed by the constructs will include a translation initiating AUG at the beginning and a termination codon (U AA, UGA or U AG) appropriately positioned at the end of the polypeptide to be translated. In addition, the constructs may contain control regions that regulate as well as engender expression. Generally, such regions will operate by controlling transcription, such as repressor binding sites and enhancers, among others. Vectors for propagation and expression generally will include selectable markers. Such markers also may be suitable for amplification or the vectors may contain additional markers for this purpose. In this regard, the expression vectors preferably contain one or more selectable marker genes to provide a phenotypic trait for selection of transformed host cells. Preferred markers include dihydrofolate reductase or neomycin resistance for eukaryotic cell culture, and tetracycline or ampicillin resistance genes for culturing E. coli and other bacteria. The vector containing the appropriate DNA sequence as described elsewhere herein, as well as an appropriate promoter, and other appropriate control sequences, may be introduced into an appropriate host using a variety of well known techniques suitable to expression therein of a desired polypeptide. Representative examples of appropriate hosts include bacterial cells, such as E. coli, Streptomyces and Salmonella typhimurium cells; fungal cells, such as yeast cells; insect cells such as Drosophila S2 and Spodoptera Sf9 cells; animal cells such as CHO, COS and Bowes melanoma cells; and plant cells. Hosts for of a great variety of expression constructs are well known, and those of skill will be enabled by the present disclosure readily to select a host for expressing a polypeptides in accordance with this aspect of the present invention. Among vectors preferred for use in bacteria are pQΕ70, pQE60 and pQE-9, available from Qiagen; pBS vectors, Phagescript vectors, Bluescript vectors, pNH8A, pNHlόa, pNH18A, pNH46A, available from Stratagene; and ptrc99a, pKK223-3, pKK233-3, pDR540, pRIT5 available from Pharmacia. Among preferred eukaryotic vectors are pWLNEO, pSV2CAT, pOG44, pXTl and pSG available from Stratagene; and pSVK3, pBPV, pMSG and pSVL available from Pharmacia. These vectors are listed solely by way of illustration of the many commercially available and well known vectors available to those of skill in the art. Selection of appropriate vectors and promoters for expression in a host cell is a well known procedure and the requisite techniques for expression vector construction, introduction of the vector into the host and expression in the host are routine skills in the art. The present invention also relates to host cells containing the above- described vector constructs described herein, and additionally encompasses host cells containing nucleotide sequences of the invention that are operably associated with one or more heterologous control regions (e.g. , promoter and/or enhancer) using techniques known of in the art. The host cell can be a higher eukaryotic cell, such as a mammalian cell (e.g. , a human derived cell), or a lower eukaryotic cell, such as a yeast cell, or the host cell can be a prokaryotic cell, such as a bacterial cell. The host strain may be chosen which modulates the expression of the inserted gene sequences, or modifies and processes the gene product in the specific fashion desired. Expression from certain promoters can be elevated in the presence of certain inducers; thus expression of the genetically engineered polypeptide may be controlled. Furthermore, different host cells have characteristics and specific mechanisms for the translational and post-translational processing and modification (e.g.. phosphorylation, cleavage) of proteins. Appropriate cell lines can be chosen to ensure the desired modifications and processing of the foreign protein expressed. Introduction of the construct into the host cell can be effected by calcium phosphate transfection, DEAE-dextran mediated transfection, cationic lipid-mediated transfection, electroporation, transduction, infection or other methods. Such methods are described in many standard laboratory manuals, such as Davis et al, Basic Methods In Molecular Biology (1986). In addition to encompassing host cells containing the vector constructs discussed herein, the invention also encompasses primary, secondary, and immortalized host cells of vertebrate origin, particularly mammalian origin, that have been engineered to delete or replace endogenous genetic material (e.g., TRID coding sequence), and/or to include genetic material (e.g., heterologous polynucleotide sequences) that is operably associated with TRID polynucleotides of the invention, and which activates, alters, and/or amplifies endogenous TRID polynucleotides. For example, techniques known in the art may be used to operably associate heterologous control regions (e.g. , promoter and/or enhancer) and endogenous TRID polynucleotide sequences via homologous recombination (see, e.g., US Patent Number 5,641,670, issued June 24, 1997; International Publication Number WO 96/2941 1 , published September 26, 1996; International Publication Number WO 94/12650, published August 4, 1994; Kolleretα/., Proc. Natl. Acad. Sci. USA 86:8932-8935 (1989); and Zijlstra et al. Nature 342:435- 438 (1989), the disclosures of each of which are incoφorated by reference in their entireties). TRID receptor polynucleotides and polypeptides may be used in accordance with the present invention for a variety of applications, particularly those that make use of the chemical and biological properties of TRID. Among these are applications in treatment of tumors, resistance to parasites, bacteria and viruses, to induce proliferation of T-cells, endothelial cells and certain hematopoietic cells, to treat restenosis, graft vs. host disease, to regulate anti-viral responses and to prevent certain autoimmune diseases after stimulation of TRID by an agonist or by a TRAIL binding facilitator. Additional applications relate to diagnosis and to treatment of disorders of cells, tissues and organisms. These aspects of the invention are discussed further below. Transgenics and "Knockouts" The proteins of the invention can also be expressed in transgenic animals. Animals of any species, including, but not limited to, mice, rats, rabbits, hamsters, guinea pigs, pigs, micro-pigs, goats, sheep, cows and non-human primates, e.g., baboons, monkeys, and chimpanzees may be used to generate transgenic animals. In a specific embodiment, techniques described herein or otherwise known in the art. are used to express polypeptides of the invention in humans, as part of a gene therapy protocol. Any technique known in the art may be used to introduce the transgene (i.e., nucleic acids of the invention) into animals to produce the founder lines of transgenic animals. Such techniques include, but are not limited to, pronuclear microinjection (Paterson etal, Appl. Microbiol Biotechnol 40:691-698 (1994); Carver et al, Biotechnology (NY) 77:1263-1270 (1993); Wright et al, Biotechnology (NY) 9:830-834 (1991); and Hoppe et al., US Patent Number 4,873,191 (1989)); retrovirus mediated gene transfer into germ lines (Van der Putten et al, Proc. Natl Acad. Sci., USA 52:6148-6152 (1985)). blastocysts or embryos; gene targeting in embryonic stem cells (Thompson et al, Cell 56:313- 321 ( 1989)); electroporation of cells or embryos (Lo, Mol Cell. Biol. 3:1803-1814 (1983)); introduction of the polynucleotides of the invention using a gene gun (see, e.g., Ulmer et al, Science 259:1145 (1993); introducing nucleic acid constructs into embryonic pleuripotent stem cells and transferring the stem cells back into the blastocyst; and sperm-mediated gene transfer (Lavitrano et al, Cell 57:1X1-123 (1989); etc. For a review of such techniques, see Gordon, "Transgenic Animals/' Intl. Rev. Cytol. 115: 111-229 (1989), which is incorporated by reference herein in its entirety. Further, the contents of each of the documents recited in this paragraph is herein incorporated by reference in its entirety. Any technique known in the art may be used to produce transgenic clones containing polynucleotides of the invention, for example, nuclear transfer into enucleated oocytes of nuclei from cultured embryonic, fetal, or adult cells induced to quiescence (Campell et al, Nature 380:64-66 (1996); Wilmut et al, Nature 555:810-813 (1997)), each of which is herein incorporated by reference in its entirety). The present invention provides for transgenic animals that carry the transgene in all their cells, as well as animals which carry the transgene in some, but not all their cells, i. e. , mosaic animals or chimeric animals. The transgene may be integrated as a single transgene or as multiple copies such as in concatamers, e.g, head-to-head tandems or head-to-tail tandems. The transgene may also be selectively introduced into and activated in a particular cell type by following, for example, the teaching of Lasko et al. (Proc. Natl. Acad. Sci. USA §9:6232-6236 ( 1992)). The regulatory sequences required for such a cell-type specific activation will depend upon the particular cell type of interest, and will be apparent to those of skill in the art. When it is desired that the polynucleotide transgene be integrated into the chromosomal site of the endogenous gene, gene targeting is preferred. Briefly, when such a technique is to be utilized, vectors containing some nucleotide sequences homologous to the endogenous gene are designed for the purpose of integrating, via homologous recombination with chromosomal sequences, into and disrupting the function of the nucleotide sequence of the endogenous gene. The transgene may also be selectively introduced into a particular cell type, thus inactivating the endogenous gene in only that cell type, by following, for example, the teaching of Gu et al. (Science 265: 103-106 ( 1994)). The regulatory sequences required for such a cell-type specific inactivation will depend upon the particular cell type of interest, and will be apparent to those of skill in the art. The contents of each of the documents recited in this paragraph is herein incorporated by reference in its entirety. Once transgenic animals have been generated, the expression of the recombinant gene may be assayed utilizing standard techniques. Initial screening may be accomplished by Southern blot analysis or PCR techniques to analyze animal tissues to verify that integration of the transgene has taken place. The level of mRNA expression of the transgene in the tissues of the transgenic animals may also be assessed using techniques which include, but are not limited to, Northern blot analysis of tissue samples obtained from the animal, in situ hybridization analysis, and reverse transcriptase-PCR (rt-PCR). Samples of transgenic gene- expressing tissue may also be evaluated immunocytochemically or immunohistochemically using antibodies specific for the transgene product. Once the founder animals are produced, they may be bred, inbred, outbred, or crossbred to produce colonies of the particular animal. Examples of such breeding strategies include, but are not limited to: outbreeding of founder animals with more than one integration site in order to establish separate lines; inbreeding of separate lines in order to produce compound transgenics that express the transgene at higher levels because of the effects of additive expression of each transgene; crossing of heterozygous transgenic animals to produce animals homozygous for a given integration site in order to both augment expression and eliminate the need for screening of animals by DNA analysis; crossing of separate homozygous lines to produce compound heterozygous or homozygous lines; and breeding to place the transgene on a distinct background that is appropriate for an experimental model of interest. Transgenic and "knock-out" animals of the invention have uses which include, but are not limited to, animal model systems useful in elaborating the biological function of TRID polypeptides, studying conditions and/or disorders associated with aberrant TRID expression, and in screening for compounds effective in ameliorating such conditions and/or disorders. In further embodiments of the invention, cells that are genetically engineered to express the proteins of the invention, or alternatively, that are genetically engineered not to express the proteins of the invention (e.g., knockouts) are administered to a patient in vivo. Such cells may be obtained from the patient (i.e.. animal, including human) or an MHC compatible donor and can include, but are not limited to fibroblasts, bone marrow cells, blood cells (e.g., lymphocytes), adipocytes, muscle cells, endothelial cells, etc. The cells are genetically engineered in vitro using recombinant DNA techniques to introduce the coding sequence of polypeptides of the invention into the cells, or alternatively, to disrupt the coding sequence and/or endogenous regulatory sequence associated with the polypeptides of the invention, e.g. , by transduction (using viral vectors, and preferably vectors that integrate the transgene into the cell genome) or transfection procedures, including, but not limited to, the use of plasmids, cosmids, YACs, naked DNA, electroporation, liposomes, etc. The coding sequence of the polypeptides of the invention can be placed under the control of a strong constitutive or inducible promoter or promoter/enhancer to achieve expression, and preferably secretion, of the polypeptides of the invention. The engineered cells which express and preferably secrete the polypeptides of the invention can be introduced into the patient systemically, e.g., in the circulation, or intraperitoneally. Alternatively, the cells can be incorporated into a matrix and implanted in the body, e.g. , genetically engineered fibroblasts can be implanted as part of a skin graft; genetically engineered endothelial cells can be implanted as part of a lymphatic or vascular graft. (See, for example, Anderson et al. US Patent Number 5,399,349; and Mulligan & Wilson, US Patent Number 5,460,959, each of which is incorporated by reference herein in its entirety). When the cells to be administered are non-autologous or non-MHC compatible cells, they can be administered using well known techniques which prevent the development of a host immune response against the introduced cells. For example, the cells may be introduced in an encapsulated form which, while allowing for an exchange of components with the immediate extracellular environment, does not allow the introduced cells to be recognized by the host immune system. TRID Polypeptides and Fragments The polypeptides of the present invention are preferably provided in an isolated form. For example, a recombinantly produced version of the TRID polypeptide can be substantially purified by the one-step method described in Smith and Johnson, Gene 67:31-40 (1988). The invention further provides an isolated TRID polypeptide having the amino acid sequences encoded by the deposited cDNA, or the amino acid sequences in SEQ ID NO:2. or a peptide or polypeptide comprising, or alternatively consisting of, a portion of the above polypeptides. Polypeptide fragments of the present invention include polypeptides comprising or alternatively, consisting of, an amino acid sequence contained in SEQ ID NO:2, encoded by the cDNA contained in the deposited clone, or encoded by nucleic acids which hybridize (e.g., under stringent hybridization conditions) to the nucleotide sequence contained in the deposited clone, or shown in SEQ ID NO: 1 or the complementary strand thereto. Protein fragments may be "free-standing," or comprised within a larger polypeptide of which the fragment forms a part or region, most preferably as a single continuous region. Representative examples of polypeptide fragments of the invention, include, for example, fragments that comprise or alternatively, consist of from about amino acid residues: 1 to 26, 27 to 50, 51 to 100, 151 to 200, 201 to 240, and/or 241 to 259, of SEQ ID NO:2. Additional representative examples of polypeptide fragments of the invention, include, for example, fragments that comprise, or alternatively consisting of, from about amino acid residues: 1-60, 1 1-70, 21 -80, 31-90, 41-100, 51-1 10, 61 -120, 71-130, 81-140, 91-150, 101-160, 1 1 1-170, 121 -180, 131-190, 141-200, 151-210. 161-220, 171-230, 181-240, 191-250, and/or 201-249 of SEQ ID NO:2, as well as isolated polynucleotides which encode these polypeptides. In this context "about" includes the particularly recited value, larger or smaller by several (5, 4, 3, 2, or 1 ) amino acids, at either extreme or at both extremes. Moreover, polypeptide fragments can be at least 10, 20, 30, 40. 50, 60, 70, 80, 90, 100, 1 10, 120, 130, 140, 150, 175 or 200 amino acids in length. Polynucleotides encoding these polypeptides are also encompassed by the invention. In specific embodiments, polypeptide fragments of the invention comprise, or alternatively consist of, amino acid residues: 1-259, 27-259, 27-240, 53-150, and/or 241-259, of TRID as depicted in SEQ ID NO:2. Polynucleotides encoding these polypeptides are also encompassed by the invention. In additional embodiments, the polypeptide fragments of the invention comprise, or alternatively consist, of one or more TRID domains. Preferred polypeptide fragments of the present invention include a member selected from the group: (a) a polypeptide comprising or alternatively, consisting of, the TRID transmembrane domain (predicted to constitute amino acid residues from about 241 to about 259 of SEQ ID NO:2); (b) a polypeptide comprising or alternatively, consisting of, the TRID receptor extracellular domain (predicted to constitute amino acid residues from about 27 to about 240 of SEQ ID NO:2); (c) a polypeptide comprising or alternatively, consisting of, the TRID cysteine rich domain (predicted to constitute amino acid residues from about 53 to about 150 of SEQ ID NO:2); (d) a polypeptide comprising or alternatively, consisting of, fragment of the predicted mature TRID polypeptide, wherein the fragment has a TRID functional activity (e.g., antigenic activity or biological acitivity); or (e) a polypeptide comprising, or alternatively consisting of, one, two, three, four or more, epitope bearing portions of the TRID receptor protein. In additional embodiments, the polypeptide fragments of the invention comprise, or alternatively consist of, any combination of (a), (b), (c), (d), or (e) of the above members. Polynucleotides encoding these polypeptides are also encompassed by the invention. As discussed above, it is believed that one or both of the extracellular cysteine rich motifs of TRID is important for interactions between TRID and its ligands (e.g. , TRAIL). Accordingly, in preferred embodiments, polypeptide fragments of the invention comprise, or alternatively consist of amino acid residues 53 to 1 10, and/or 1 1 1 to 153 of SEQ ID NO:2. In a specific embodiment the polypeptides of the invention comprise, or alternatively consist of both of the extracellular cysteine rich motifs disclosed in SEQ ID NO:2. Polynucleotides encoding these polypeptides are also encompassed by the invention. Among the especially preferred fragments of the invention are fragments characterized by structural or functional attributes of TRID. Such fragments include amino acid residues that comprise alpha-helix and alpha-helix forming regions ("alpha-regions"), beta-sheet and beta-sheet-forming regions ("beta- regions"), turn and turn-forming regions ("turn-regions"), coil and coil-forming regions ("coil-regions"), hydrophilic regions, hydrophobic regions, alpha amphipathic regions, beta amphipathic regions, surface forming regions, and high antigenic index regions (i.e., containing four or more contiguous amino acids having an antigenic index of greater than or equal to 1.5, as identified using the default parameters of the Jameson- Wolf program) of complete (i.e., full-length) TRID (SEQ ID NO:2). Certain preferred regions are those set out in Figure 3 and include, but are not limited to, regions of the aforementioned types identified by analysis of the amino acid sequence depicted in SEQ ID NO:2, such preferred regions include; Garnier-Robson predicted alpha-regions, beta-regions, turn- regions, and coil-regions; Chou-Fasman predicted alpha-regions, beta-regions, and turn-regions; Kyte-Doolittle predicted hydrophilic and Hopp- Woods hydrophobic regions; Eisenberg alpha and beta amphipathic regions; Emini surface-forming regions; and Jameson- Wolf high antigenic index regions, as predicted using the default parameters of these computer programs. Polynucleotides encoding these polypeptides are also encompassed by the invention. Among highly preferred fragments in this regard are those that comprise, or alternatively consist of, regions of TRID that combine several structural features, such as several of the features set out above. The present invention encompasses TRID proteins containing the polypeptide sequence encoded by the polynucleotides of the invention. The TRID proteins of the invention may be in monomers or multimers (/. e. , dimers, trimers, tetramers, and higher multimers). Accordingly, the present invention relates to monomers and multimers of the TRID proteins of the invention, their preparation, and compositions (preferably, pharmaceutical compositions) containing them. In specific embodiments, the polypeptides of the invention are monomers, dimers, trimers or tetramers. In additional embodiments, the multimers of the invention are at least dimers, at least trimers, or at least tetramers. Multimers encompassed by the invention may be homomers or heteromers. As used herein, the term homomer, refers to a multimer containing only TRID proteins of the invention (including TRID fragments, variants, and fusion proteins, as described herein). These homomers may contain TRID proteins having identical or different polypeptide sequences. In a specific embodiment, a homomer of the invention is a multimer containing only TRID proteins having an identical polypeptide sequence. In another specific embodiment, a homomer of the invention is a multimer containing TRID proteins having different polypeptide sequences. In specific embodiments, the multimer of the invention is a homodimer (e.g. , containing TRID proteins having identical or different polypeptide sequences) or a homotrimer (e.g., containing TRID proteins having identical or different polypeptide sequences). In additional embodiments, the homomeric multimer of the invention is at least a homodimer, at least a homotrimer, or at least a homotetramer. As used herein, the term heteromer refers to a multimer containing heterologous proteins (i.e., proteins containing only polypeptide sequences that do not correspond to a polypeptide sequences encoded by the TRID gene) in addition to the TRID proteins of the invention. In a specific embodiment, the multimer of the invention is a heterodimer, a heterotrimer, or a heterotetramer. In additional embodiments, the heteromeric multimer of the invention is at least a heterodimer, at least a heterotrimer, or at least a heterotetramer. Multimers of the invention may be the result of hydrophobic, hydrophilic, ionic and/or covalent associations and/or may be indirectly linked, by for example, liposome formation. Thus, in one embodiment, multimers of the invention, such as, for example, homodimers or homotrimers, are formed when proteins of the invention contact one another in solution. In another embodiment, heteromultimers of the invention, such as, for example, heterotrimers or heterotetramers, are formed when proteins of the invention contact antibodies to the polypeptides of the invention (including antibodies to the heterologous polypeptide sequence in a fusion protein of the invention) in solution. In other embodiments, multimers of the invention are formed by covalent associations with and/or between the TRID proteins of the invention. Such covalent associations may involve one or more amino acid residues contained in the polypeptide sequence of the protein (e.g., the polypeptide sequence recited in SEQ ID NO:2 or the polypeptide encoded by the deposited cDNA clone). In one instance, the covalent associations are cross-linking between cysteine residues located within the polypeptide sequences of the proteins which interact in the native (i.e., naturally occurring) polypeptide. In another instance, the covalent associations are the consequence of chemical or recombinant manipulation. Alternatively, such covalent associations may involve one or more amino acid residues contained in the heterologous polypeptide sequence in a TRID fusion protein. In one example, covalent associations are between the heterologous sequence contained in a fusion protein of the invention (see, e.g., US Patent Number 5,478,925). In a specific example, the covalent associations are between the heterologous sequence contained in a TRID-Fc fusion protein of the invention (as described herein). In another specific example, covalent associations of fusion proteins of the invention are between heterologous polypeptide sequences from another TNF family ligand/receptor member that is capable of forming covalently associated multimers, such as for example, oseteoprotegerin (see, e.g. , International Publication No. WO 98/49305, the contents of which are herein incorporated by reference in its entirety). The multimers of the invention may be generated using chemical techniques known in the art. For example, proteins desired to be contained in the multimers of the invention may be chemically cross-linked using linker molecules and linker molecule length optimization techniques known in the art (see, e.g. , US Patent Number 5,478,925, which is herein incorporated by reference in its entirety). Additionally, multimers of the invention may be generated using techniques known in the art to form one or more inter-molecule cross-links between the cysteine residues located within the polypeptide sequence of the proteins desired to be contained in the multimer (see, e.g., US Patent Number 5,478,925, which is herein incorporated by reference in its entirety). Further, proteins of the invention may be routinely modified by the addition of cysteine or biotin to the C terminus or N-terminus of the polypeptide sequence of the protein and techniques known in the art may be applied to generate multimers containing one or more of these modified proteins (see, e.g., US Patent Number 5,478,925, which is herein incoφorated by reference in its entirety). Additionally, techniques known in the art may be applied to generate liposomes containing the protein components desired to be contained in the multimer of the invention (see, e.g. , US Patent Number 5,478,925, which is herein incoφorated by reference in its entirety). Alternatively, multimers of the invention may be generated using genetic engineering techniques known in the art. In one embodiment, proteins contained in multimers of the invention are produced recombinantly using fusion protein technology described herein or otherwise known in the art (see, e.g., US Patent Number 5,478,925, which is herein incoφorated by reference in its entirety). In a specific embodiment, polynucleotides coding for a homodimer of the invention are generated by ligating a polynucleotide sequence encoding a polypeptide of the invention to a sequence encoding a linker polypeptide and then further to a synthetic polynucleotide encoding the translated product of the polypeptide in the reverse orientation from the original C-terminus to the N-terminus (lacking the leader sequence) (see, e.g., US Patent Number 5,478,925, which is herein incoφorated by reference in its entirety). In another embodiment, recombinant techniques described herein or otherwise known in the art are applied to generate recombinant polypeptides of the invention which contain a transmembrane domain and which can be incorporated by membrane reconstitution techniques into liposomes (see, e.g., US Patent Number 5,478,925, which is herein incoφorated by reference in its entirety). N-Terminal and C-Terminal Deletion Mutants To improve or alter the characteristics of a TRID polypeptide, protein engineering may be employed. Recombinant DNA technology known to those skilled in the art can be used to create novel mutant proteins or "muteins" including single or multiple amino acid substitutions, deletions, additions or fusion proteins. Such modified polypeptides can show, e.g., enhanced activity or increased stability. In addition, they may be purified in higher yields and show better solubility than the corresponding natural polypeptide, at least under certain purification and storage conditions. For instance, for many proteins, including the extracellular domain of a membrane associated protein or the mature form(s) of a secreted protein, it is known in the art that one or more amino acids may be deleted from the N- terminus or C-terminus without substantial loss of biological function. For instance, Ron et al, J. Biol. Chem., 2(55:2984-2988 (1993) reported modified KGF proteins that had heparin binding activity even if 3, 8, or 27 amino-terminal amino acid residues were missing. In the present case, since the proteins of the invention are members of the TNFR polypeptide family, deletions of N-terminal amino acids up to the cysteine at position C-53 of SEQ ID NO:2 may retain some biological activity such as regulation of proliferation and apoptosis of lymphoid cells. Polypeptides having further N-terminal deletions including the C-53 residue in SEQ ID NO:2, would not be expected to retain such biological activities because it is known that these residues in a TRID-related polypeptide are required for forming a disulfide bridge to provide structural stability which is needed for ligand binding. However, even if deletion of one or more amino acids from the N-terminus of a protein results in modification or loss of one or more biological functions of the protein, other functional activities (e.g., biological activities, ability to multimerize, ability to bind TRIAL ligand) may still be retained. For example, the ability of the shortened protein to induce and/or bind to antibodies which recognize the complete or mature form of the TRID protein generally will be retained when less than the majority of the residues of the complete protein or extracellular domain are removed from the N-terminus. Whether a particular polypeptide lacking N-terminal residues of a complete protein retains such immunologic activities can readily be determined by routine methods described herein and otherwise known in the art. TRID muteins with a large number of deleted N-terminal amino acid residues are expected to retain some biological or immunogenic activities. In fact, peptides composed of as few as six TRID amino acid residues may often evoke an immune response. Accordingly, the present invention further provides polypeptides having one or more residues deleted from the amino terminus of the amino acid sequence shown in SEQ ID NO:2, up to the cysteine residue in each which is at position number 53, and polynucleotides encoding such polypeptides. In particular, the present invention provides TRID polypeptides comprising, or alternatively consisting of, the amino acid sequence of residues n'-259 of SEQ ID NO:2 where n 1 is an integer in the range of 1-53 where 53 is the position of the first cysteine residue from the N-terminus of the complete TRID polypeptide (shown in SEQ ID NO:2) believed to be required for activity of the TRID protein. More in particular, the invention provides polynucleotides encoding polypeptides having the amino acid sequence of residues: M-1 to V-259; A-2 to V-259; R-3 to V-259; 1-4 to V-259; P-5 to V-259; K-6 to V-259; T-7 to V-259; L-8 to V-259; K-9 to V-259; F-10 to V-259; V-l 1 to V-259; V-12 to V-259; V- 13 to V-259; 1-14 to V-259; V-15 to V-259; A-16 to V-259; V-17 to V-259; L- 18 to V-259; L-19 to V-259; P-20 to V-259; V-21 to V-259; L-22 to V-259; A- 23 to V-259; Y-24 to V-259; S-25 to V-259; A-26 to V-259; T-27 to V-259; T- 28 to V-259; A-29 to V-259; R-30 to V-259; Q-31 to V-259; E-32 to V-259; E- 33 to V-259; V-34 to V-259; P-35 to V-259; Q-36 to V-259; Q-37 to V-259; T- 38 to V-259; V-39 to V-259; A-40 to V-259; P-41 to V-259; Q-42 to V-259; Q- 43 to V-259; Q-44 to V-259; R-45 to V-259; H-46 to V-259; S-47 to V-259; F- 48 to V-259; K-49 to V-259; G-50 to V-259; E-51 to V-259; E-52 to V-259; and/or C-53 to V-259 of SEQ ID NO:2. Polynucleotides encoding these polypeptides also are provided. The present invention is also directed to nucleic acid molecules comprising, or alternatively consisting of, a polynucleotide sequence at least 80%, 85%, 90%, 92%, 95%, 96%, 97%, 98%, or 99% identical to the polynucleotide sequences encoding the polypeptides described above. The invention is further directed to nucleic acid molecules comprising, or alternatively consisting of, polynucleotide sequences which encode polypeptides that are at least 80%, 85%, 90%, 92%, 95%, 96%, 97%, 98%, or 99% identical to the polypeptides described above. The present invention also encompasses the above polynucleotide sequences fused to a heterologous polynucleotide sequence. Polypeptides encoded by these polynucleotides are also encompassed by the invention. Similarly, the present invention further provides polypeptides having one or more residues deleted from the amino terminus of the TRID amino acid sequence shown in SEQ ID NO:2, up to the leucine residue at position number 255 and polynucleotides encoding such polypeptides. In particular, the present invention provides polypeptides comprising, or alternatively consisting of, the amino acid sequence of residues n 2 -259 of SEQ ID NO:2, where n 2 is an integer from 2 to 254 corresponding to the position of the amino acid residue in SEQ ID NO:2. More in particular, the invention provides polynucleotides encoding polypeptides comprising, or alternatively consisting of, the amino acid sequence of residues of A-2 to V-259; R-3 to V-259; 1-4 to V-259; P-5 to V-259; K-6 to V-259; T-7 to V-259; L-8 to V-259 K-9 to V-259; F-10 to V-259; V-l l to V- 259; V-12 to V-259; V-13 to V-259 1-14 to V-259; V-15 to V-259 A-16 to V- 259; V-17 to V-259 L-18 to V-259 L-19 to V-259; P-20 to V-259 V-21 to V- 259; L-22 to V-259 A-23 to V-259 Y-24 to V-259; S-25 to V-259 A-26 to V- 259 T-27 to V-259 T-28 to V-259: A-29 to V-259; R-30 to V-259 Q-31 to V- 259 E-32 to V-259 E-33 to V-259 V-34 to V-259; P-35 to V-259 Q-36 to V- 259 Q-37 to V-259 T-38 to V-259 V-39 to V-259; A-40 to V-259 P-41 to V- 259 Q-42 to V-259 Q-43 to V-259 Q-44 to V-259; R-45 to V-259: H-46 to V- 259 S-47 to V-259 F-48 to V-259 K-49 to V-259; G-50 to V-259 E-51 to V- 259 E-52 to V-259 C-53 to V-259 P-54 to V-259; A-55 to V-259 G-56 to V- 259 S-57 to V-259 H-58 to V-259 R-59 to V-259; S-60 to V-259 E-61 to V- 259 H-62 to V-259 T-63 to V-259; G-64 to V-259; A-65 to V-259 C-66 to V- 259 N-67 to V-259 P-68 to V-259 C-69 to V-259; T-70 to V-259 E-71 to V- 259 G-72 to V-259 V-73 to V-259 D-74 to V-259; Y-75 to V-259 T-76 to V- 259 N-77 to V-259 A-78 to V-259 S-79 to V-259; N-80 to V-259 N-81 to V- 259 E-82 to V-259 P-83 to V-259 S-84 to V-259; C-85 to V-259 F-86 to V- 259 P-87 to V-259 C-88 to V-259 T-89 to V-259; V-90 to V-259 C-91 to V- 259 K-92 to V-259 S-93 to V-259 D-94 to V-259; Q-95 to V-259; K-96 to V- 259 H-97 to V-259 K-98 to V-259; S-99 to V-259; S-100 to V-259; C-101 to V-259; T-102 to V-259; M-103 to V-259; T-104 to V-259; R-105 to V-259; D- 106 to V-259; T-107 to V-259; V-108 to V-259; C-109 to V-259; Q-1 10 to V- 259; C-l 1 1 to V-259; K-l 12 to V-259; E-l 13 to V-259; G-l 14 to V-259; T-l 15 to V-259; F-116 to V-259; R-l 17 to V-259; N-l 18 to V-259; E-l 19 to V-259; N-120 to V-259; S-121 to V-259; P-122 to V-259; E-l 23 to V-259; M-124 to V- 259; C-125 to V-259; R-l 26 to V-259; K-127 to V-259; C-128 to V-259; S-129 to V-259; R-l 30 to V-259; C-131 to V-259; P-132 to V-259; S-133 to V-259; G-134 to V-259; E-135 to V-259; V-136 to V-259; Q-137 to V-259; V-138 to V-259; S-139 to V-259; N-140 to V-259; C-141 to V-259; T-142 to V-259; S- 143 to V-259; W-144 to V-259; D-145 to V-259; D-146 to V-259; 1-147 to V- 259; Q-148 to V-259; C-149 to V-259; V-150 to V-259; E-151 to V-259; E-152 to V-259; F-153 to V-259; G-154 to V-259; A-155 to V-259; N-156 to V-259; A-157 to V-259; T-158 to V-259; V-159 to V-259; E-l 60 to V-259; T-161 to V- 259; P-162 to V-259; A-163 to V-259; A-164 to V-259; E-165 to V-259; E-166 to V-259; T-167 to V-259; M-168 to V-259; N-169 to V-259; T-170 to V-259; S-171 to V-259; P-172 to V-259; G-173 to V-259; T-174 to V-259; P-175 to V- 259; A- 176 to V-259; P-177 to V-259; A-178 to V-259; A- 179 to V-259; E-180 to V-259; E-181 to V-259; T-182 to V-259; M-183 to V-259; N-184 to V-259; T-185 to V-259; S-186 to V-259; P-187 to V-259; G-188 to V-259; T-189 to V- 259; P-190 to V-259; A-191 to V-259; P-192 to V-259; A- 193 to V-259; A- 194 to V-259; E-195 to V-259; E-l 96 to V-259; T-197 to V-259; M-198 to V-259; T-199 to V-259; T-200 to V-259; S-201 to V-259; P-202 to V-259; G-203 to V- 259; T-204 to V-259; P-205 to V-259; A-206 to V-259; P-207 to V-259; A-208 to V-259; A-209 to V-259; E-210 to V-259; E-21 1 to V-259; T-212 to V-259; M-213 to V-259; T-214 to V-259; T-215 to V-259; S-216 to V-259; P-217 to V- 259; G-218 to V-259; T-219 to V-259; P-220 to V-259; A-221 to V-259; P-222 to V-259; A-223 to V-259; A-224 to V-259; E-225 to V-259; E-226 to V-259; T-227 to V-259; M-228 to V-259; T-229 to V-259; T-230 to V-259; S-231 to V- 259; P-232 to V-259; G-233 to V-259; T-234 to V-259; P-235 to V-259; A-236 to V-259; S-237 to V-259; S-238 to V-259; H-239 to V-259; Y-240 to V-259; L-241 to V-259; S-242 to V-259; C-243 to V-259; T-244 to V-259; 1-245 to V- 259; V-246 to V-259; G-247 to V-259; 1-248 to V-259; 1-249 to V-259; V-250 to V-259; L-251 to V-259; 1-252 to V-259; V-253 to V-259; and/or L-254 to V- 259; of the TRID sequence shown in SEQ ID NO:2. Polypeptides encoded by these polynucleotides are also encompassed by the invention. The present invention is also directed to nucleic acid molecules comprising, or alternatively consisting of, a polynucleotide sequence at least 80%, 85%, 90%, 92%, 95%, 96%, 97%, 98%, or 99% identical to the polynucleotide sequences encoding the polypeptides described above. The invention is further directed to nucleic acid molecules comprising, or alternatively consisting of, polynucleotide sequences which encode polypeptides that are at least 80%, 85%, 90%, 92%, 95%, 96%, 97%, 98%, or 99% identical to the polypeptides described above. The present invention also encompasses the above polynucleotide sequences fused to a heterologous polynucleotide sequence. Polypeptides encoded by these polynucleotides are also encompassed by the invention. Similarly, many examples of biologically functional C-terminal deletion muteins are known. For instance, interferon gamma shows up to ten times higher activities by deleting 8-10 amino acid residues from the carboxy terminus of the protein (Dobeli et al, J. Biotechnology 7: 199-216 (1988)). In the present case, since the protein of the invention is a member of the TNFR polypeptide family, deletions of C-terminal amino acids up to the cysteine at position 149 of SEQ ID NO:2, may retain some biological activity such as regulation of proliferation and apoptosis of lymphoid cells. Polypeptides having further C-terminal deletions including the cysteine at position 149 of SEQ ID NO:2 would not be expected to retain such biological activities because it is known that this residue in TNF receptor-related polypeptides is required for forming a disulfide bridge to provide structural stability which is needed for ligand binding. Also as mentioned above, even if deletion of one or more amino acids from the C-terminus of a protein results in modification or loss of one or more biological functions of the protein, other functional activities (e.g., biological activities, ability to multimerize, ability to bind TRID ligand) may still be retained. Thus, the ability of the shortened protein to induce and/or bind to antibodies which recognize the complete or mature form of the protein generally will be retained when less than the majority of the residues of the complete or mature form protein are removed from the C-terminus. Whether a particular polypeptide lacking C-terminal residues of a complete protein retains such immunologic activities can readily be determined by routine methods described herein and otherwise known in the art. TRID muteins with a large number of deleted C-terminal amino acid residues are expected to retain some biological or immunogenic activities. In fact, peptides composed of as few as six TRID amino acid residues may often evoke an immune response. Accordingly, the present invention further provides polypeptides having one or more residues from the carboxy terminus of the amino acid sequence of TRID shown in SEQ ID NO:2 up to the cysteine at position 149 of SEQ ID NO:2, and polynucleotides encoding such polypeptides. In particular, the present invention provides polypeptides having the amino acid sequence of residues 1 -m 1 of the amino acid sequence in SEQ ID NO:2, where m' is any integer in the range of 149-259. Polynucleotides encoding these polypeptides also are provided. More in particular, the invention provides polynucleotides encoding polypeptides comprising, or alternatively consisting of, the amino acid sequence of residues: M-1 to V-259; M-1 to F-258; M-1 to V-257; M-1 to 1-256; M-1 to L-255; M-1 to L-254; M-1 to V-253; M-1 to 1-252; M-1 to L-251 ; M-1 to V-250; M-1 to 1-249; M-1 to 1-248; M-1 to G-247; M-1 to V-246; M-1 to 1-245; M-1 to T-244; M-1 to C-243; M-1 to S-242; M-1 to L-241 ; M-1 to Y-240; M-1 to H- 239; M-1 to S-238; M-1 to S-237; M-1 to A-236; M-1 to P-235; M-1 to T-234; M-1 to G-233; M-1 to P-232; M-1 to S-231 ; M-1 to T-230; M-1 to T-229; M-1 to M-228; M-1 to T-227; M-1 to E-226; M-1 to E-225; M-1 to A-224; M-1 to A- 223; M-1 to P-222; M-1 to A-221; M-1 to P-220; M-1 to T-219; M-1 to G-218; M-1 to P-217; M-1 to S-216; M-1 to T-215; M-1 to T-214; M-1 to M-213; M-1 to T-212; M-1 to E-21 1 ; M-1 to E-210; M-1 to A-209; M-1 to A-208; M-1 to P- 207; M-1 to A-206; M-1 to P-205; M-1 to T-204; M-1 to G-203; M-1 to P-202; M-1 to S-201 ; M-l to T-200; M-l to T-199; M-l to M-198; M-l to T-197; M-l to E-196; M-1 to E-195; M-1 to A-194; M-1 to A-193; M-1 to P-192; M-1 to A- 191 ; M-1 to P-190; M-1 to T-189; M-1 to G-188; M-1 to P-187; M-1 to S-186; M-1 to T-185; M-1 to N-184; M-1 to M-183; M-1 to T-182; M-1 to E-181 ; M-1 to E-180; M-1 to A-179; M-1 to A-178; M-1 to P-177; M-1 to A-176; M-1 to P- 175; M-1 to T-174; M-1 to G-173; M-1 to P-172; M-1 to S-171 ; M-1 to T-170; M-1 to N-169; M-1 to M-168; M-1 to T-167; M-1 to E-166; M-1 to E-165; M-1 to A-164; M-1 to A-163; M-1 to P-162; M-1 to T-161 ; M-1 to E-160; M-1 to V- 159; M-1 to T-158; M-1 to A-157; M-1 to N-156; M-1 to A-155; M-1 to G-154; M-l to F-153; M-1 to E-152; M-1 to E-151 ; M-1 to V-150; and/or M-1 to C-149. Polypeptides encoded by these polynucleotides are also encompassed by the invention. The present invention is also directed to nucleic acid molecules comprising, or alternatively consisting of, a polynucleotide sequence at least 80%, 85%, 90%, 92%, 95%, 96%, 97%, 98%, or 99% identical to the polynucleotide sequences encoding the polypeptides described above. The invention is further directed to nucleic acid molecules comprising, or alternatively consisting of, polynucleotide sequences which encode polypeptides that are at least 80%, 85%, 90%, 92%, 95%, 96%, 97%, 98%, or 99% identical to the polypeptides described above. The present invention also encompasses the above polynucleotide sequences fused to a heterologous polynucleotide sequence. Polypeptides encoded by these polynucleotides are also encompassed by the invention. The present invention further provides polypeptides having one or more residues deleted from the carboxy terminus of the amino acid sequence of the TRID polypeptide shown in SEQ ID NO:2, up to the lysine residue at position number 6, and polynucleotides encoding such polypeptides. In particular, the present invention provides polypeptides comprising, or alternatively consisting of, the amino acid sequence of residues 1 -nr of SEQ ID NO:2, where m 2 is an integer from 6 to 258 corresponding to the position of the amino acid residue in SEQ ID NO:2. More in particular, the invention provides polynucleotides encoding polypeptides comprising, or alternatively consisting of, the amino acid sequence of residues: M-1 to F-258; M-1 to V-257; M-1 to 1-256; M-1 to L-255; M-1 to L-254; M-1 to V-253; M-1 to 1-252; M-1 to L-251 ; M-1 to V-250; M-1 to 1-249; M-1 to 1-248; M-1 to G-247; M-1 to V-246: M-1 to 1-245; M-1 to T-244; M-1 to C-243; M-1 to S-242; M-1 to L-241 ; M-1 to Y-240; M-1 to H-239; M-1 to S- 238; M-1 to S-237; M-1 to A-236; M-1 to P-235; M-1 to T-234; M-1 to G-233; M-1 to P-232; M-1 to S-231; M-1 to T-230; M-1 to T-229; M-1 to M-228; M-1 to T-227; M-1 to E-226; M-1 to E-225; M-1 to A-224; M-1 to A-223; M-1 to P- 222; M-1 to A-221 ; M-1 to P-220; M-1 to T-219; M-1 to G-218; M-1 to P-217; M-l to S-216; M-1 to T-215; M-1 to T-214; M-1 to M-213; M-1 to T-212; M-1 to E-211; M-1 to E-210; M-1 to A-209; M-1 to A-208; M-1 to P-207; M-1 to A- 206; M-1 to P-205; M-1 to T-204; M-1 to G-203; M-1 to P-202; M-1 to S-201; M-1 to T-200; M-1 to T-199; M-1 to M-198; M-1 to T-197; M-1 to E-196; M-1 to E-195; M-1 to A-194; M-1 to A-193; M-1 to P-192; M-1 to A-191; M-1 to P- 190; M-1 to T-189; M-1 to G-188; M-1 to P-187; M-1 to S-186; M-1 to T-185; M-1 to N-184; M-1 to M-183; M-1 to T-182; M-1 to E-181; M-1 to E-180; M-1 to A-179; M-1 to A-178; M-1 to P-177; M-1 to A-176; M-1 to P-175; M-1 to T- 174; M-1 toG-173;M-l toP-172;M-l to S-171; M-1 to T-170; M-1 toN-169; M-1 to M-168; M-1 to T-167; M-1 to E-166; M-1 to E-165; M-1 to A-164; M-1 to A-163; M-1 to P-162; M-1 toT-161;M-l toE-160;M-l toV-159;M-l to T- 158; M-1 to A-157; M-1 to N-156; M-1 to A-155; M-1 to G-154; M-1 to F-153; M-1 to E-152; M-1 to E-151; M-1 to V-150; M-1 to C-149; M-1 to Q-148; M-1 to 1-147; M-1 to D-146; M-1 to D-145; M-1 to W-144; M-1 to S-143; M-1 to T- 142; M-1 to C-141; M-1 to N-140; M-1 to S-139; M-1 to V-138; M-1 to Q-137; M-1 to V-136; M-1 to E-135; M-1 to G-134; M-1 to S-133; M-1 to P-132; M-1 to C-131; M-1 to R-130; M-1 to S-129; M-1 to C-128; M-1 to K-127; M-1 to R- 126; M-1 to C-125; M-1 to M-124; M-1 to E-123; M-1 to P-122; M-1 to S-121; M-1 toN-120;M-l to E-l 19; M-1 toN-118;M-l to R-l 17; M-1 toF-116;M-l to T-l 15; M-1 to G-l 14; M-1 to E-l 13; M-1 to K-l 12; M-1 to C-l 11; M-1 to Q- 110; M-1 toC-109;M-l toV-108;M-l to T-107; M-1 to D-106; M-1 toR-105; M-1 to T-104; M-1 to M-103; M-1 to T-102; M-1 to C-101; M-1 to S-100; M-1 to S-99; M-1 to K-98; M-1 to H-97; M-1 to K-96; M-1 to Q-95; M-1 to D-94; M-1 to S-93; M-1 to K-92; M-1 to C-91; M-1 to V-90; M-1 to T-89; M-1 to C- 88; M-1 to P-87; M-1 to F-86; M-1 to C-85; M-1 to S-84; M-1 to P-83; M-1 to E-82;M-1 toN-81;M-l toN-80;M-l to S-79; M-1 toA-78;M-l toN-77;M-l to T-76; M-1 to Y-75; M-1 to D-74; M-1 to V-73; M-1 to G-72; M-1 to E-71; M-1 to T-70; M-1 to C-69; M-1 to P-68; M-1 to N-67; M-1 to C-66; M-1 to A- 65; M-1 to G-64; M-1 to T-63; M-1 to H-62; M-1 to E-61; M-1 to S-60; M-1 to R-59; M-1 to H-58; M-1 to S-57; M-1 to G-56; M-1 to A-55; M-1 to P-54; M-1 to C-53; M-1 to E-52; M-1 to E-51; M-1 to G-50; M-1 to K-49; M-1 to F-48; M- 1 to S-47; M-1 to H-46; M-1 to R-45; M-1 to Q-44; M-1 to Q-43; M-1 to Q-42; M-1 to P-41 ; M-1 to A-40; M-1 to V-39; M-1 to T-38; M-1 to Q-37; M-1 to Q- 36; M-1 to P-35; M-1 to V-34; M-1 to E-33; M-1 to E-32; M-1 to Q-31 ; M-1 to R-30; M-1 to A-29; M-1 to T-28; M-1 to T-27; M-1 to A-26; M-1 to S-25; M-1 to Y-24; M-1 to A-23; M-1 to L-22; M-1 to V-21 ; M-1 to P-20; M-1 to L-19; M- 1 to L-18; M-1 to V-17; M-1 to A-16; M-1 to V-15; M-1 to 1-14; M-1 to V-13; M-1 to V-12; M-l to V-1 1 ; M-1 to F-10; M-l to K-9; M-1 to L-8; M-1 to T-7; and/or M-1 to K-6; ofthe TRID sequence shown in SEQ ID NO:2. Polypeptides encoded by these polynucleotides are also encompassed by the invention. The present invention is also directed to nucleic acid molecules comprising, or alternatively consisting of, a polynucleotide sequence at least 80%, 85%, 90%, 92%, 95%, 96%, 97%, 98%, or 99% identical to the polynucleotide sequences encoding the polypeptides described above. The invention is further directed to nucleic acid molecules comprising, or alternatively consisting of, polynucleotide sequences which encode polypeptides that are at least 80%, 85%, 90%, 92%, 95%, 96%, 97%, 98%, or 99% identical to the polypeptides described above. The present invention also encompasses the above polynucleotide sequences fused to a heterologous polynucleotide sequence. Polypeptides encoded by these polynucleotides are also encompassed by the invention. Similarly, the present invention further provides polypeptides having one or more residues deleted from the carboxy terminus ofthe amino acid sequence ofthe extracellular domain ofthe TRID polypeptide shown in SEQ ID NO:2, up to the glutamine residue at position number 33, and polynucleotides encoding such polypeptides. In particular, the present invention provides polypeptides comprising, or alternatively consisting of, the amino acid sequence of residues 27-m 3 of SEQ ID NO:2, where m 3 is an integer from 33 to 259 corresponding to the position ofthe amino acid residue in SEQ ID NO:2. More in particular, the invention provides polynucleotides encoding polypeptides comprising, or alternatively consisting of, the amino acid sequence of residues: T-27 to F-258; T-27 to V-257; T-27 to 1-256; T-27 to L-255; T-27 to L-254; T-27 to V-253; T-27 to 1-252; T-27 to L-251 ; T-27 to V-250; T-27 to 1-249; T-27 to 1-248 T-27 to G-247; T-27 to V-246; T-27 to 1-245; T-27 to T- 244; T-27 to C-243; T-27 to S-242; T-27 to L-241; T-27 to Y-240; T-27 to H- 239; T-27 to S-238; T-27 to S-237; T-27 to A-236; T-27 to P-235; T-27 to T- 234; T-27 to G-233; T-27 to P-232; T-27 to S-231; T-27 to T-230; T-27 to T- 229 T-27 to M-228 T-27 to T-227; T-27 to E-226; T-27 to E-225; T-27 to A- 224. T-27 to A-223; T-27 to P-222; T-27 to A-221; T-27 to P-220; T-27 to T- 219. T-27 to G-218; T-27 to P-217; T-27 to S-216; T-27 to T-215; T-27 to T- 214 T-27 to M-213 T-27 to T-212; T-27 to E-211; T-27 to E-210; T-27 to A- 209 T-27 to A-208; T-27 to P-207; T-27 to A-206; T-27 to P-205; T-27 to T- 204 T-27 to G-203; T-27 to P-202; T-27 to S-201; T-27 to T-200; T-27 to T- 199 T-27 to M-198 T-27 to T-197; T-27 to E-196; T-27 to E-195; T-27 to A- 194 T-27 to A- 193; T-27 to P-192; T-27 to A-191; T-27 to P-190; T-27 to T- 189 T-27 to G- 188; T-27 to P-187; T-27 to S-186; T-27 to T-185; T-27 to N- 184 T-27 to M-183 T-27 to T-182; T-27 to E-181; T-27 to E-180; T-27 to A- 179 T-27 to A- 178; T-27 to P-177; T-27 to A-176; T-27 to P-175; T-27 to T- 174 T-27 to G- 173; T-27 to P-172; T-27 to S-171; T-27 to T-170; T-27 to N- 169 T-27 to M-168 T-27 to T-167; T-27 to E-166; T-27 to E-165; T-27 to A- 164 T-27 to A-163; T-27 to P-162; T-27 to T-161; T-27 to E-160; T-27 to V- 159 , T-27 to T-158; T-27 to A-157; T-27 to N-156; T-27 to A-155; T-27 to G- 154 T-27 to F-153; T-27 to E-152; T-27 to E-151; T-27 to V-150; T-27 to C- 149 T-27 to Q-148; T-27 to 1-147; T-27 to D-146; T-27 to D-145: T-27 to W- 144 , T-27 to S-143; T-27 to T-142; T-27 to C-141; T-27 to N-140; T-27 to S- 139 , T-27 to V-138; T-27 to Q-137; T-27 to V-136; T-27 to E-135; T-27 to G- 134 , T-27 to S-133; T-27 to P-132; T-27 to C-131; T-27 to R-130; T-27 to S- 129 , T-27 to C-128; T-27 to K-127; T-27 to R-126; T-27 to C-125; T-27 to M- 124 , T-27 to E-l 23; T-27 to P-122; T-27 to S-121; T-27 to N-120; T-27 to E- 119 , T-27 to N-1 18; T-27 to R-l 17; T-27 to F-116; T-27 to T-115; T-27 to G- 1 14 ; T-27 to E-l 13; T-27 to K-l 12; T-27 to C-lll; T-27 to Q-110; T-27 to C- 109 ; T-27 to V-108; T-27 to T-107; T-27 to D-106; T-27 to R-l05; T-27 to T- 104 ; T-27 to M-103; T-27 to T-102; T-27 to C-101; T-27 to S-100; T-27 to S-99; T-2 7 to K-98; T-27 tto H-97; T-27 to K-96; T-27 to Q-95; T-27 to D-94; T-27 to S-93; T-27 to K-92; T-27 to C-91 ; T-27 to V-90; T-27 to T-89; T-27 to C-88; T- 27 to P-87; T-27 to F-86; T-27 to C-85; T-27 to S-84; T-27 to P-83; T-27 to E- 82; T-27 to N-81 ; T-27 to N-80; T-27 to S-79; T-27 to A-78; T-27 to N-77; T-27 to T-76; T-27 to Y-75; T-27 to D-74; T-27 to V-73; T-27 to G-72; T-27 to E-71 ; T-27 to T-70; T-27 to C-69; T-27 to P-68; T-27 to N-67; T-27 to C-66; T-27 to A-65; T-27 to G-64; T-27 to T-63; T-27 to H-62; T-27 to E-61 ; T-27 to S-60; T- 27 to R-59; T-27 to H-58; T-27 to S-57; T-27 to G-56; T-27 to A-55; T-27 to P- 54; T-27 to C-53 ; T-27 to E-52; T-27 to E-51 ; T-27 to G-50; T-27 to K-49; T-27 to F-48; T-27 to S-47; T-27 to H-46; T-27 to R-45; T-27 to Q-44; T-27 to Q-43; T-27 to Q-42; T-27 to P-41 ; T-27 to A-40; T-27 to V-39; T-27 to T-38; T-27 to Q-37; T-27 to Q-36; T-27 to P-35; T-27 to V-34; and/or T-27 to E-33; of the TRID extracellular domain sequence shown in SEQ ID NO:2. Polypeptides encoded by these polynucleotides are also encompassed by the invention. The present invention is also directed to nucleic acid molecules comprising, or alternatively consisting of, a polynucleotide sequence at least 80%, 85%, 90%. 92%, 95%, 96%, 97%, 98%, or 99% identical to the polynucleotide sequences encoding the polypeptides described above. The invention is further directed to nucleic acid molecules comprising, or alternatively consisting of, polynucleotide sequences which encode polypeptides that are at least 80%, 85%, 90%, 92%, 95%, 96%, 97%, 98%, or 99% identical to the polypeptides described above. The present invention also encompasses the above polynucleotide sequences fused to a heterologous polynucleotide sequence. Polypeptides encoded by these polynucleotides are also encompassed by the invention. The invention also provides polypeptides having one or more amino acids deleted from both the amino and the carboxyl termini, which may be described generally as having residues n'-m 1 , n 2 -m', n'-m 2 , n 2 -m\ n'-m 3 , or n 2 -m 3 of SEQ ID NO:2, where n 1 , n 2 , m 1 , m\ and m 3 are integers as described above. Also included are a nucleotide sequence encoding a polypeptide consisting of a portion of a complete TRID amino acid sequence encoded by a cDNA clone contained in ATCC Deposit No. 97798, where this portion excludes from 1 to about 49 amino acids from the amino terminus of the complete amino acid sequence encoded by the cDNA clone contained in ATCC Deposit No. 97798, or from 1 to about 1 10 amino acids from the carboxy terminus ofthe complete amino acid sequence encoded by the cDNA clone contained in ATCC Deposit No. 97798, or any combination of the above amino terminal and carboxy terminal deletions, of the complete amino acid sequence encoded by the cDNA clone contained in ATCC Deposit No. 97798. Polynucleotides encoding all of the above deletion mutant polypeptide forms also are provided. Other Mutants In addition to terminal deletion forms of the protein discussed above, it will also be recognized by one of ordinary skill in the art that some amino acid sequences ofthe TRID polypeptide can be varied without significant effect on the structure or function of the proteins. If such differences in sequence are contemplated, it should be remembered that there will be critical areas on the protein which determine activity. Thus, the invention further includes variations ofthe TRID polypeptide, which show substantial TRID polypeptide activity or which include regions of TRID protein such as the protein portions discussed below. Such mutants include deletions, insertions, inversions, repeats, and type substitutions. Guidance concerning which amino acid changes are likely to be phenotypically silent can be found in Bowie, J. U. et al., "Deciphering the Message in Protein Sequences: Tolerance to Amino Acid Substitutions," Science 247: 1306-1310 (1990). Thus, the fragment, derivative, or analog of the polypeptide of SEQ ID NO:2, or that encoded by the deposited cDNA, may be: (i) one in which one or more of the amino acid residues are substituted with a conserved or non- conserved amino acid residue (preferably a conserved amino acid residue(s), and more preferably at least one but less than ten conserved amino acid residue(s)), and such substituted amino acid residue(s) may or may not be one encoded by the genetic code; or (ii) one in which one or more ofthe amino acid residues includes a substituent group;or (iii) one in which the mature or soluble extracellular polypeptide is fused with another compound, such as a compound to increase the half-life ofthe polypeptide (for example, polyethylene glycol); or (iv) one in which the additional amino acids are fused to the mature polypeptide, such as an IgG Fc fusion region peptide or leader or secretory sequence or a sequence which is employed for purification of the mature polypeptide or a proprotein sequence. Such fragments, derivatives and analogs are deemed to be within the scope of those skilled in the art from the teachings herein. Thus, the TRID ofthe present invention may include one or more amino acid substitutions, deletions or additions, either from natural mutations or human manipulation. As indicated, changes are preferably of a minor nature, such as conservative amino acid substitutions that do not significantly affect the folding or activity of the protein (see Table 2). TABLE 2. Conservative Amino Acid Substitutions In specific embodiments, the number of substitutions, additions or deletions in the amino acid sequence of SEQ ID NO:2 and/or any of the polypeptide fragments described herein (e.g., the extracellular domain or transmembrane domain) is 75, 70, 60, 50, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 or 30-20, 20-15, 20-10, 15-10, 10-1, 5-10, 1-5, 1-3 or 1-2. Amino acids in the TRID protein ofthe present invention that are essential for function can be identified by methods known in the art, such as site-directed mutagenesis or alanine-scanning mutagenesis (Cunningham and Wells, Science 244: 1081 - 1085 (1989)). The latter procedure introduces single alanine mutations at every residue in the molecule. The resulting mutant molecules are then tested for biological activity such as receptor binding or in vitro proliferative activity. Of particular interest are substitutions of charged amino acids with another charged amino acids and with neutral or negatively charged amino acids. The latter results in proteins with reduced positive charge to improve the characteristics of the TRID protein. The prevention of aggregation is highly desirable. Aggregation of proteins not only results in a loss of activity but can also be problematic when preparing pharmaceutical formulations, because they can be immunogenic. (Pinckard et al, Clin Exp. Immunol. 2:331-340 (1967); Robbins et al, Diabetes 56:838-845 (1987); Cleland et al, Crit. Rev. Therapeutic Drug Carrier Systems 10:301-311 (1993)). The replacement of amino acids can also change the selectivity of binding of a ligand to cell surface receptors. For example, Ostade et al, Nature 361:266- 268 (1993), describes certain mutations resulting in selective binding of TNF-α to only one of the two known types of TNF receptors. Sites that are critical for ligand-receptor binding can also be determined by structural analysis such as crystallization, nuclear magnetic resonance or photoaffinity labeling (Smith et al. , J. Mol Biol 224:899-904 (1992) and de Vos et al, Science 255:306-312 (1992)). Non-naturally occurring variants may be produced using art-known mutagenesis techniques, which include, but are not limited to oligonucleotide mediated mutagenesis, alanine scanning, PCR mutagenesis, site directed mutagenesis (see e.g., Carter et al, Nucl. Acids Res. 75:4331 (1986); and Zoller et al, Nucl. Acids Res. 10:6481 (1982)), cassette mutagenesis (see e.g., Wells et al , Gene 54:315 (1985)), restriction selection mutagenesis (see e.g. , Wells et al , Philos. Trans. R. Soc. london Ser A 577:415 (1986)). Thus, the invention also encompasses TRID derivatives and analogs that have one or more amino acid residues deleted, added, or substituted to generate TRID polypeptides that are better suited for expression, scale up, etc., in the host cells chosen. For example, cysteine residues can be deleted or substituted with another amino acid residue in order to eliminate disulfide bridges; N-linked glycosylation sites can be altered or eliminated to achieve, for example, expression of a homogeneous product that is more easily recovered and purified from yeast hosts which are known to hyperglycosylate N-linked sites. To this end, a variety of amino acid substitutions at one or both ofthe first or third amino acid positions on any one or more of the glycosylation recognitions sequences in the TRID polypeptides ofthe invention, and/or an amino acid deletion at the second position of any one or more such recognition sequences will prevent glycosylation ofthe TRID at the modified tripeptide sequence (see, e.g., Miyajimo et al., EMBO J 5(6):1 193-1197). The present inventors have discovered that the TRID polypeptide is a 259 residue protein exhibiting two main structural domains. First, the extracellular TRAIL ligand binding domain was identified within residues from about 27 to about 240 in SEQ ID NO:2. Second, the transmembrane domain was identified within residues from about 241 to about 259 in SEQ ID NO:2. As mentioned above, however. TRID. suφrisingly lacks a putative intracellular signalling domain, thus, the name "TRID" (TRAIL Receptor Without an Intracellular Domain"). The polypeptides ofthe present invention include the polypeptide encoded by the deposited cDNA including the leader; the mature polypeptide encoded by the deposited the cDNA minus the leader (i. e. , the mature protein); a polypeptide comprising, or alternatively consisting of, amino acids about 1 to about 259 in SEQ ID NO:2; a polypeptide comprising, or alternatively consisting of, amino acids about 2 to about 259 in SEQ ID NO:2 as well as polypeptides which are at least 80% identical, more preferably at least 90% or 95% identical, still more preferably at least 96%, 97%, 98%, or 99% identical to the polypeptides described above, and also include portions of such polypeptides with at least 30 amino acids and more preferably at least 50 amino acids. By a polypeptide having an amino acid sequence at least, for example, 95% "identical" to a reference amino acid sequence of a TRID polypeptide is intended that the amino acid sequence of the polypeptide is identical to the reference sequence except that the polypeptide sequence may include up to five amino acid alterations per each 100 amino acids ofthe reference amino acid ofthe TRID polypeptide. In other words, to obtain a polypeptide having an amino acid sequence at least 95% identical to a reference amino acid sequence, up to 5% of the amino acid residues in the reference sequence may be deleted or substituted with another amino acid, or a number of amino acids up to 5% ofthe total amino acid residues in the reference sequence may be inserted into the reference sequence. These alterations ofthe reference sequence may occur at the amino or carboxy terminal positions of the reference amino acid sequence or anywhere between those terminal positions, interspersed either individually among residues in the reference sequence or in one or more contiguous groups within the reference sequence. As a practical matter, whether any particular polypeptide is at least 90%, 95%, 96%, 97%, 98% or 99% identical to, for instance, the amino acid sequence shown in SEQ ID NO:2, or to the amino acid sequence encoded by the deposited cDNA clone, can be determined conventionally using known computer programs such the Bestfit program (Wisconsin Sequence Analysis Package, Version 8 for Unix, Genetics Computer Group, University Research Park, 575 Science Drive, Madison, WI 53711). When using Bestfit or any other sequence alignment program to determine whether a particular sequence is, for instance, 95% identical to a reference sequence according to the present invention, the parameters are set, of course, such that the percentage of identity is calculated over the full length of the reference amino acid sequence and that gaps in homology of up to 5% ofthe total number of amino acid residues in the reference sequence are allowed. In a specific embodiment, the identity between a reference (query) sequence (a sequence of the present invention) and a subject sequence, also referred to as a global sequence alignment, is determined using the FASTDB computer program based on the algorithm of Brutlag et al. (Comp. App. Biosci. 6:231-245 (1990)). Preferred parameters used in a FASTDB amino acid alignment are: Matrix=PAM 0, k-tuple=2, Mismatch Penalty=l, Joining Penalty=20, Randomization Group Length=0, Cutoff Score=l , Window Size=sequence length, Gap Penalty=5, Gap Size Penalty=0.05, Window Size=500 or the length ofthe subject amino acid sequence, whichever is shorter. According to this embodiment, if the subject sequence is shorter than the query sequence due to N- or C-terminal deletions, not because of internal deletions, a manual correction is made to the results to take into consideration the fact that the FASTDB program does not account for N- and C-terminal truncations of the subject sequence when calculating global percent identity. For subject sequences truncated at the N- and C-termini, relative to the query sequence, the percent identity is corrected by calculating the number of residues ofthe query sequence that are N- and C-terminal ofthe subject sequence, which are not matched/aligned with a corresponding subject residue, as a percent ofthe total bases ofthe query sequence. A determination of whether a residue is matched/aligned is determined by results ofthe FASTDB sequence alignment. This percentage is then subtracted from the percent identity, calculated by the above FASTDB program using the specified parameters, to arrive at a final percent identity score. This final percent identity score is what is used for the purposes of this embodiment. Only residues to the N- and C-termini ofthe subject sequence, which are not matched/aligned with the query sequence, are considered for the puφoses of manually adjusting the percent identity score. That is, only query residue positions outside the farthest N- and C-terminal residues ofthe subject sequence. For example, a 90 amino acid residue subject sequence is aligned with a 100 residue query sequence to determine percent identity. The deletion occurs at the N-terminus ofthe subject sequence and therefore, the FASTDB alignment does not show a matching/alignment ofthe first 10 residues at the N-terminus. The 10 unpaired residues represent 10% of the sequence (number of residues at the N- and C- termini not matched/total number of residues in the query sequence) so 10% is subtracted from the percent identity score calculated by the FASTDB program. If the remaining 90 residues were perfectly matched the final percent identity would be 90%. In another example, a 90 residue subject sequence is compared with a 100 residue query sequence. This time the deletions are internal deletions so there are no residues at the N- or C-termini ofthe subject sequence which are not matched/aligned with the query. In this case the percent identity calculated by FASTDB is not manually corrected. Once again, only residue positions outside the N- and C-terminal ends ofthe subject sequence, as displayed in the FASTDB alignment, which are not matched/aligned with the query sequence are manually corrected for. No other manual corrections are made for the puφoses of this embodiment. The polypeptide ofthe present invention have uses which include, but are not limited to, as sources for generating antibodies that bind the polypeptides of the invention, and as a molecular weight marker on SDS-PAGE gels or on molecular sieve gel filtration columns using methods well known to those of skill in the art. The present application is also directed to proteins containing polypeptides at least 90%, 95%, 96%, 97%, 98% or 99% identical to the TRID polypeptide sequence set forth herein as n'-259, n 2 -259,l-m', 1-m 2 , l-m J , n'-m', n 2 -m', n'-m 2 , n 2 -m 2 , n'-m 3 , or n 2 -m 3 of SEQ ID NO:2, where n', n 2 , m 1 , m 2 , and m 3 are integers as described above. In preferred embodiments, the application is directed to proteins containing polypeptides at least 90%, 95%, 96%, 97%, 98% or 99% identical to polypeptides having the amino acid sequence ofthe specific TRID N- and C-terminal deletions recited herein. Polynucleotides encoding these polypeptides are also encompassed by the invention. In certain preferred embodiments, TRID proteins of the invention comprise, or alternatively consist of, fusion proteins as described herein wherein the TRID polypeptides are those described as n'-259, n 2 -259, 1-m', 1-m 2 , l-m 3 , n'- m 1 , n 2 -m', n'-m 2 , n 2 -m 2 , n'-m 3 , or n 2 -m 3 of SEQ ID NO:2, where n', n 2 , m', m 2 , and m 3 are integers as described above. In preferred embodiments, the application is directed to nucleic acid molecules at least 90%, 95%, 96%, 97%, 98% or 99% identical to the nucleic acid sequences encoding polypeptides having the amino acid sequence of the specific N- and C-terminal deletions recited herein. Polynucleotides encoding these polypeptides are also encompassed by the invention. Epitope-Bearing Portions The present invention encompasses polypeptides comprising, or alternatively consisting of, an epitope of the polypeptide having an amino acid sequence of SEQ ID NO:2, or an epitope ofthe polypeptide sequence encoded by a polynucleotide sequence contained in the cDNA assigned ATCC Accession No. 97798, encoded by a polynucleotide that hybridizes to the complement of the sequence of SEQ ID NO : 1 , or contained in the cDN A assigned ATCC Accession No. 97798 under stringent hybridization conditions or lower stringency hybridization conditions as defined supra. The present invention further encompasses polynucleotide sequences encoding an epitope of a polypeptide sequence ofthe invention (such as, for example, the sequence disclosed in SEQ ID NOT), polynucleotide sequences of the complementary strand of a polynucleotide sequence encoding an epitope ofthe invention, and polynucleotide sequences which hybridize to the complementary strand under stringent hybridization conditions or lower stringency hybridization conditions defined supra. The term "epitopes," as used herein, refers to portions of a polypeptide having antigenic or immunogenic activity in an animal, preferably a mammal, and most preferably in a human. In a preferred embodiment, the present invention encompasses a polypeptide comprising an epitope, as well as the polynucleotide encoding this polypeptide. An "immunogenic epitope," as used herein, is defined as a portion of a protein that elicits an antibody response in an animal, as determined by any method known in the art, for example, by the methods for generating antibodies described infra. (See, for example, Geysen et al. , Proc. Natl. Acad. Sci. USA 57:3998-4002 (1983)). The term "antigenic epitope," as used herein, is defined as a portion of a protein to which an antibody can immunospecifically bind its antigen as determined by any method well known in the art, for example, by the immunoassays described herein. Immunospecific binding excludes non-specific binding but does not necessarily exclude cross- reactivity with other antigens. Antigenic epitopes need not necessarily be immunogenic. Fragments that function as epitopes may be produced by any conventional means. (See, e.g., Houghten, Proc. Natl. Acad. Sci. USA 52:5131-5135 (1985), further described in U.S. Patent No. 4,631,21 1). Antigenic epitope-bearing peptides and polypeptides ofthe invention are therefore useful to raise antibodies, including monoclonal antibodies, that bind specifically to a polypeptide ofthe invention. See, for instance, Wilson et al, Cell 57:767-778 (1984) at 777. In the present invention, antigenic epitopes preferably contain a sequence of at least 4, at least 5, at least 6, at least 7, more preferably at least 8, at least 9, at least 10, at least 15, at least 20, at least 25, and. most preferably, between about 15 to about 30 amino acids contained within the amino acid sequence of a polypeptide ofthe invention. Preferred polypeptides comprising immunogenic or antigenic epitopes are at least 10, 15. 20, 25, 30, 35, 40, 45, 50, 55. 60, 65, 70, 75, 80, 85, 90, 95, or 100 amino acid residues in length. Antigenic epitopes are useful, for example, to raise antibodies, including monoclonal antibodies, that specifically bind the epitope. Antigenic epitopes can be used as the target molecules in immunoassays. (See, for instance, Wilson et al, Cell 37:767-778 ( 1984); Sutcliffe et al. , Science 219:660-666 (1983)). Polynucleotides encoding these polypeptides are also encompassed by the invention. Similarly, immunogenic epitopes can be used, for example, to induce antibodies according to methods well known in the art. (See, for instance, Sutcliffe et al, supra; Wilson et al, supra; Chow et al, Proc. Natl. Acad. Sci. USA 82:910-914; and Bittle et al, J. Gen. Virol. 66:2347-2354 (1985). A preferred immunogenic epitope includes the secreted protein. The polypeptides comprising one or more immunogenic epitopes may be presented for eliciting an antibody response together with a carrier protein, such as an albumin, to an animal system (such as, for example, rabbit or mouse), or, if the polypeptide is of sufficient length (at least about 25 amino acids), the polypeptide may be presented without a carrier. However, immunogenic epitopes comprising as few as 8 to 10 amino acids have been shown to be sufficient to raise antibodies capable of binding to, at the very least, linear epitopes in a denatured polypeptide (e.g., in Western blotting). Epitope-bearing polypeptides of the present invention may be used to induce antibodies according to methods well known in the art including, but not limited to, in vivo immunization, in vitro immunization, and phage display methods. See, e.g., Sutcliffe et al, supra; Wilson et al, supra, and Bittle et al, J. Gen. Virol, (5(5:2347-2354 (1985). Ifin vivo immunization is used, animals may be immunized with free peptide; however, anti-peptide antibody titer may be boosted by coupling the peptide to a macromolecular carrier, such as keyhole limpet hemacyanin (KLH) or tetanus toxoid. For instance, peptides containing cysteine residues may be coupled to a carrier using a linker such as maleimidobenzoyl-N-hydroxysuccinimide ester (MBS), while other peptides may be coupled to carriers using a more general linking agent such as glutaraldehyde. Animals such as, for example, rabbits, rats, and mice are immunized with either free or carrier-coupled peptides, for instance, by intraperitoneal and/or intradermal injection of emulsions containing about 100 micrograms of peptide or carrier protein and Freund's adjuvant or any other adjuvant known for stimulating an immune response. Several booster injections may be needed, for instance, at intervals of about two weeks, to provide a useful titer of anti-peptide antibody that can be detected, for example, by ELISA assay using free peptide adsorbed to a solid surface. The titer of anti-peptide antibodies in serum from an immunized animal may be increased by selection of anti-peptide antibodies, for instance, by adsoφtion to the peptide on a solid support and elution ofthe selected antibodies according to methods well known in the art. As to the selection of peptides or polypeptides bearing an antigenic epitope (i.e., that contain a region of a protein molecule to which an antibody can bind), it is well known in that art that relatively short synthetic peptides that mimic part of a protein sequence are routinely capable of eliciting an antiserum that reacts with the partially mimicked protein. See, for instance, Sutcliffe, J. G., et al., "Antibodies That React With Predetermined Sites on Proteins," Science, 219:660-666 (1983). Peptides capable of eliciting protein-reactive sera are frequently represented in the primary sequence of a protein, can be characterized by a set of simple chemical rules, and are confined neither to immunodominant regions of intact proteins (i.e., immunogenic epitopes) nor to the amino or carboxyl terminals. Antigenic epitope-bearing peptides and polypeptides ofthe invention are therefore useful to raise antibodies, including monoclonal antibodies, that bind specifically to a polypeptide ofthe invention. See, for instance, Wilson et al, Cell 37:161-118 (1984) at 777. Non-limiting examples of antigenic polypeptides or peptides that can be used to generate TRID-specific antibodies include: a polypeptide comprising, or alternatively consisting of, amino acid residues from about Gln-42 to about Glu-52 in SEQ ID NO:2; a polypeptide comprising, or alternatively consisting of, amino acid residues from about His-58 to about Cys-66 in SEQ ID NO:2; a polypeptide comprising, or alternatively consisting of. amino acid residues from about Pro-68 to about Thr-76 in SEQ ID NO:2; a polypeptide comprising, or alternatively consisting of, amino acid residues from about Ser-79 to about Cys-85 in SEQ ID NO:2; a polypeptide comprising, or alternatively consisting of, amino acid residues from about Cys-91 to about Thr- 102 in SEQ ID NO:2; a polypeptide comprising, or alternatively consisting of, amino acid residues from about Gln-1 10 to about Pro-122 in SEQ ID NO:2; a polypeptide comprising, or alternatively consisting of, amino acid residues from about Arg- 126 to about Val- 136 in SEQ ID NO:2; and a polypeptide comprising, or alternatively consisting of, amino acid residues from about Thr-142 to about Gin- 148 in SEQ ID NO:2. As indicated above, the inventors have determined that the above polypeptide fragments are antigenic regions of theTRID protein. Polynucleotides encoding these polypeptides are also encompassed by the invention. The epitope-bearing peptides and polypeptides of the invention may be produced by any conventional means *See, e.g., Houghten, R. A. "General method for the rapid solid-phase synthesis of large numbers of peptides: specificity of antigen-antibody interaction at the level of individual amino acids. " Proc. Natl. Acad. Sci. USA 52:5131-5135 (1985); this "Simultaneous Multiple Peptide Synthesis (SMPS)" process is further described in U.S. Patent No. 4,631,21 1 to Houghten et al (1986)). Further still, U.S. Patent No. 5,194,392 to Geysen (1990) describes a general method of detecting or determining the sequence of monomers (amino acids or other compounds) which is a topological equivalent ofthe epitope (i.e., a "mimotope") which is complementary to a particular paratope (antigen binding site) of an antibody of interest. More generally, U.S. Patent No. 4,433,092 to Geysen (1989) describes a method of detecting or determining a sequence of monomers which is a topographical equivalent of a ligand which is complementary to the ligand binding site of a particular receptor of interest. Similarly, U.S. Patent No. 5,480.971 to Houghten, R. A. et al. (1996) on Peralkylated Oligopeptide Mixtures discloses linear C 1 -C7-alkyl peralkylated oligopeptides and sets and libraries of such peptides, as well as methods for using such oligopeptide sets and libraries for determining the sequence of a peralkylated oligopeptide that preferentially binds to an acceptor molecule of interest. Thus, non-peptide analogs of the epitope-bearing peptides of the invention also can be made routinely by these methods. Fusion Proteins and Modified Proteins As one of skill in the art will appreciate, TRID receptor polypeptides ofthe present invention and the epitope-bearing fragments thereof described herein above (e.g. , corresponding to a portion ofthe extracellular domain, such as, for example, polypeptide sequence comprising, or alternatively, consisting of, amino acid residues 1 to 240, 27 to 240, 30 to 240, 35 to 240, 40 to 240 and 50 to 240 of SEQ ID NO:2) fused to other polypeptide sequences. For example, the polypeptides ofthe present invention may be fused with the constant domain of immunoglobulins (IgA, IgE, IgG, IgM), or portions thereof (CHI, CH2, CH3, or any combination thereof and portions thereof) resulting in chimeric polypeptides. Such fusion proteins may facilitate purification and may increase half-life in vivo. This has been shown for chimeric proteins consisting ofthe first two domains of the human CD4-polypeptide and various domains ofthe constant regions ofthe heavy or light chains of mammalian immunoglobulins. See, e.g., EP 394,827; Traunecker et al, Nature, 331:84-86 (1988). IgG Fusion proteins that have a disulfide-linked dimeric structure due to the IgG portion disulfide bonds have also been found to be more efficient in binding and neutralizing other molecules than monomeric polypeptides or fragments thereof alone. See, e.g. , Fountoulakis et al. , J Biochem., 270:3958-3964 (1995). Nucleic acids encoding the above epitopes can also be recombined with a gene of interest as an epitope tag (e.g. , the hemagglutinin ("HA") tag or flag tag) to aid in detection and purification ofthe expressed polypeptide. For example, a system described by Janknecht et al. allows for the ready purification of non-denatured fusion proteins expressed in human cell lines (Janknecht et al , 1991 , Proc. Natl. Acad. Sci. USA 88:8972- 897). In this system, the gene of interest is subcloned into a vaccinia recombination plasmid such that the open reading frame of the gene is translationally fused to an amino-terminal tag consisting of six histidine residues. The tag serves as a matrix-binding domain for the fusion protein. Extracts from cells infected with the recombinant vaccinia virus are loaded onto Ni 2+ nitriloacetic acid-agarose column and histidine-tagged proteins can be selectively eluted with imidazole-containing buffers. Additional fusion proteins ofthe invention may be generated through the techniques of gene-shuffling, motif-shuffling, exon-shuffling, and/or codon- shuffling (collectively referred to as "DNA shuffling"). DNA shuffling may be employed to modulate the activities of polypeptides of the invention, such methods can be used to generate polypeptides with altered activity, as well as agonists and antagonists of the polypeptides. See, generally, U.S. Patent Nos. 5,605,793; 5,81 1,238; 5,830,721 ; 5,834,252; and 5,837,458, and Patten et al, Curr. Opinion Biotechnol. 8:724-33 (1997); Harayama, Trends Biotechnol. 16(2):76-82 (1998); Hanssonetα/., J. Mol. Biol.287:265-76 (1999); and Lorenzo and Blasco, Biotechniques 24(2):308-13 (1998) (each of these patents and publications are hereby incoφorated by reference in its entirety). In one embodiment, alteration of polynucleotides corresponding to SEQ ID NO: 1 and the polypeptides encoded by these polynucleotides may be achieved by DNA shuffling. DNA shuffling involves the assembly of two or more DNA segments by homologous or site-specific recombination to generate variation in the polynucleotide sequence. In another embodiment, polynucleotides of the invention, or the encoded polypeptides, may be altered by being subjected to random mutagenesis by error-prone PCR, random nucleotide insertion or other methods prior to recombination. In another embodiment, one or more components, motifs, sections, parts, domains, fragments, etc., of a polynucleotide coding a polypeptide of the invention may be recombined with one or more components, motifs, sections, parts, domains, fragments, etc. of one or more heterologous molecules. As one of skill in the art will appreciate, TRID polypeptides ofthe present invention and the epitope-bearing fragments thereof described herein (e.g., corresponding to a portion ofthe extracellular domain such as, for example, amino acid residues 1 to 240 of SEQ ID NO:2) can be combined with parts of the constant domain of immunoglobulins (IgG), resulting in chimeric polypeptides. These fusion proteins facilitate purification and show an increased half-life in vivo. This has been shown, e.g., for chimeric proteins consisting of the first two domains of the human CD4-polypeptide and various domains of the constant regions of the heavy or light chains of mammalian immunoglobulins (EPA 394,827; Traunecker et al, Nature 331:84- 86 (1988)). Fusion proteins that have a disulfide-linked dimeric structure due to the IgG part can also be more efficient in binding and neutralizing other molecules than the monomeric TRID protein or protein fragment alone (Fountoulakis et al, J Biochem 270:3958-3964 (1995)). The epitope-bearing peptides and polypeptides ofthe invention may be produced by any conventional means. Houghten, R.A., "General method for the rapid solid-phase synthesis of large numbers of peptides: specificity of antigen-antibody interaction at the level of individual amino acids," Proc. Natl. Acad. Sci. USA 52:5131-5135 (1985). This "Simultaneous Multiple Peptide Synthesis (SMPS)" process is further described in U.S. Patent No. 4,631,21 1 to Houghten et al. (1986). The polypeptide may be expressed in a modified form, such as a fusion protein, and can include not only secretion signals but also additional heterologous functional regions. Thus, for instance, a region of additional amino acids, particularly charged amino acids, can be added to the N-terminus of the polypeptide to improve stability and persistence in the host cell, during purification or during subsequent handling and storage. Also, peptide moieties can be added to the polypeptide to facilitate purification. Such regions can be removed prior to final preparation of the polypeptide. The addition of peptide moieties to polypeptides to engender secretion or excretion, to improve stability and to facilitate purification, among others, are familiar and routine techniques in the art. A preferred fusion protein comprises a heterologous region from immunoglobulin that is useful to solubilize proteins. For example, EP-A-O 464 533 (Canadian counteφart 2045869) discloses fusion proteins comprising various portions of constant region of immunoglobin molecules together with another human protein or part thereof. In many cases, the Fc part in a fusion protein is thoroughly advantageous for use in therapy and diagnosis and thus results, for example, in improved pharmacokinetic properties (EP-A 0232262). On the other hand, for some uses, it would be desirable to be able to delete the Fc part after the fusion protein has been expressed, detected and purified in the advantageous manner described. This is the case when the Fc portion proves to be a hindrance to use in therapy and diagnosis, for example, when the fusion protein is to be used as an antigen for immunizations. In drug discovery, for example, human proteins, such as the hIL5-receptor, have been fused with Fc portions for the purpose of high-throughput screening assays to identify antagonists of hIL-5. See, D. Bennett et al. , Journal of Molecular Recognition 8:52-58 (1995) and K. Johanson et al. , The Journal of Biological Chemistry 270: 16:9459-9471 (1995). In another embodiment, TRID receptor polypeptides of the present invention and the epitope-bearing fragments thereof described herein above (e.g. , corresponding to a portion of the extracellular domain, such as, for example, polypeptide sequence comprising, or alternatively, consisting of, amino acid residues 1 to 240, 27 to 240, 30 to 240, 35 to 240, 40 to 240 and 50 to 240 of SEQ ID NO:2) can be combined as a fusion protein with a polypeptide having intracellular signaling activity which is activated upon ligand binding. For example, a TRID polypeptide of the present invention can be coupled with the intracellular activation domain of a heterologous TNF-family receptor. Such a fusion protein, when expressed in a host cell, would, when bound to TRAIL, activate a detectable signal, such as, but not limited to, apoptosis or NF-kB activation . Such a fusion protein is useful for screening for ligand binding, or screening for agonists and/or antagonists of a TRID polypeptide. In addition, proteins ofthe invention can be chemically synthesized using techniques known in the art (e.g., see Creighton, Proteins: Structures and Molecular Principles, W.H. Freeman & Co., N.Y. (1983), and Hunkapiller, M., et al, Nature 570: 105-1 1 1 (1984)). For example, a peptide corresponding to a fragment ofthe TRID polypeptides ofthe invention can be synthesized by use of a peptide synthesizer. Furthermore, if desired, nonclassical amino acids or chemical amino acid analogs can be introduced as a substitution or addition into the TRID polypeptide sequence. Non-classical amino acids include, but are not limited to, to the D-isomers ofthe common amino acids, 2,4-diaminobutyric acid, a-amino isobutyric acid, 4-aminobutyric acid, Abu, 2-amino butyric acid, g-Abu, e-Ahx, 6-amino hexanoic acid, Aib, 2-amino isobutyric acid, 3-amino propionic acid, ornithine, norleucine, norvaline, hydroxyproline, sarcosine, citrulline, homocitrulline, cysteic acid, t-butylglycine, t-butylalanine, phenylglycine, cyclohexylalanine, b-alanine, fluoro-amino acids, designer amino acids such as b- methyl amino acids, Ca-methyl amino acids, Na-methyl amino acids, and amino acid analogs in general. Furthermore, the amino acid can be D (dextrorotary) or L (levorotary). Non-naturally occurring variants may be produced using art-known mutagenesis techniques, which include, but are not limited to oligonucleotide mediated mutagenesis, alanine scanning, PCR mutagenesis, site directed mutagenesis (see, e.g., Carter et al, Nucl. Acids Res. 75:4331 (1986); and Zoller et al, Nucl. Acids Res. 10:6481 (1982)), cassette mutagenesis (see, e.g., Wells et al, Gene 34:3 5 (1985)), restriction selection mutagenesis (see, e.g., Wells etal, Philos. Trans. R. Soc. london Ser A 577:415 (1986)). The TRID polypeptides ofthe invention can be recovered and purified by well-known methods including ammonium sulfate or ethanol precipitation, acid extraction, anion or cation exchange chromatography, phosphocellulose chromatography, hydrophobic interaction chromatography, affinity chromatography, hydroxylapatite chromatography and lectin chromatography. Most preferably, high performance liquid chromatography ("HPLC") is employed for purification. Polypeptides ofthe present invention include naturally purified products, products of chemical synthetic procedures, and products produced by recombinant techniques from a prokaryotic or eukaryotic host, including, for example, bacterial, yeast, higher plant, insect and mammalian cells. Depending upon the host employed in a recombinant production procedure, the polypeptides of the present invention may be glycosylated or non-glycosylated. In addition, polypeptides of the invention may also include an initial modified methionine residue, in some cases as a result of host-mediated processes. The invention additionally, encompasses TRID polypeptides which are differentially modified during or after translation, e.g., by glycosylation, acetylation, phosphorylation, amidation, derivatization by known protecting/blocking groups, proteolytic cleavage, linkage to an antibody molecule or other cellular ligand, etc. Any of numerous chemical modifications may be carried out by known techniques, including but not limited to, specific chemical cleavage by cyanogen bromide, trypsin, chymotrypsin, papain, V8 protease, NaBH 4 acetylation, formylation, oxidation, reduction, metabolic synthesis in the presence of tunicamycin, etc. Additional post-translational modifications encompassed by the invention include, for example, e.g. , N-linked or O-linked carbohydrate chains, processing of N-terminal or C-terminal ends), attachment of chemical moieties to the amino acid backbone, chemical modifications of N-linked or O-linked carbohydrate chains, and addition or deletion of an N-terminal methionine residue as a result of procaryotic host cell expression. The polypeptides may also be modified with a detectable label, such as an enzymatic, fluorescent, isotopic or affinity label to allow for detection and isolation ofthe protein. Also provided by the invention are chemically modified derivatives of TRID which may provide additional advantages such as increased solubility, stability and circulating time ofthe polypeptide, or decreased immunogenicity (see U. S. Patent No. 4,179,337). The chemical moieties for derivitization may be selected from water soluble polymers such as polyethylene glycol, ethylene glycol/propylene glycol copolymers, carboxymethylcellulose, dextran, polyvinyl alcohol and the like. The polypeptides may be modified at random positions within the molecule, or at predetermined positions within the molecule and may include one, two, three or more attached chemical moieties. The polymer may be of any molecular weight, and may be branched or unbranched. For polyethylene glycol, the preferred molecular weight is between about 1 kDa and about 100 kDa (the term "about" indicating that in preparations of polyethylene glycol, some molecules will weigh more, some less, than the stated molecular weight) for ease in handling and manufacturing. Other sizes may be used, depending on the desired therapeutic profile (e.g. , the duration of sustained release desired, the effects, if any on biological activity, the ease in handling, the degree or lack of antigenicity and other known effects ofthe polyethylene glycol to a therapeutic protein or analog). For example, the polyethylene glycol may have an average molecular weight of about 200, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8500, 9000, 9500, 10,000, 10,500, 1 1,000, 1 1,500, 12,000, 12,500, 13,000, 13,500, 14,000, 14,500, 15,000, 15,500, 16,000, 16,500. 17,000, 17,500, 18,000, 18.500, 19,000, 19,500, 20,000, 25,000, 30,000, 35,000.40,000, 50,000, 55,000. 60,000, 65,000, 70,000, 75,000, 80,000, 85,000, 90,000, 95,000, or 100,000 kDa. The polyethylene glycol molecules (or other chemical moieties) should be attached to the protein with consideration of effects on functional or antigenic domains ofthe protein. There are a number of attachment methods available to those skilled in the art, e.g., EP 0 401 384, herein incorporated by reference (coupling PEG to G-CSF), see also Malik et al, Exp. Hematol 20:1028-1035 (1992) (reporting pegylation of GM-CSF using tresyl chloride). For example, polyethylene glycol may be covalently bound through amino acid residues via a reactive group, such as, a free amino or carboxyl group. Reactive groups are those to which an activated polyethylene glycol molecule may be bound. The amino acid residues having a free amino group may include ly sine residues and the N-terminal amino acid residues; those having a free carboxyl group may include aspartic acid residues glutamic acid residues and the C-terminal amino acid residue. Sulfhydryl groups may also be used as a reactive group for attaching the polyethylene glycol molecules. Preferred for therapeutic purposes is attachment at an amino group, such as attachment at the N-terminus or lysine group. As suggested above, polyethylene glycol may be attached to proteins via linkage to any of a number of amino acid residues. For example, polyethylene glycol can be linked to a proteins via covalent bonds to lysine, histidine, aspartic acid, glutamic acid, or cysteine residues. One or more reaction chemistries may be employed to attach polyethylene glycol to specific amino acid residues (e.g.. lysine, histidine, aspartic acid, glutamic acid, or cysteine) ofthe protein or to more than one type of amino acid residue (e.g. , lysine, histidine, aspartic acid, glutamic acid, cysteine and combinations thereof) ofthe protein. One may specifically desire proteins chemically modified at the N-terminus. Using polyethylene glycol as an illustration ofthe present composition, one may select from a variety of polyethylene glycol molecules (by molecular weight, branching, etc.), the proportion of polyethylene glycol molecules to protein (or peptide) molecules in the reaction mix, the type of pegylation reaction to be performed, and the method of obtaining the selected N-terminally pegylated protein. The method of obtaining the N-terminally pegylated preparation (i.e., separating this moiety from other monopegylated moieties if necessary) may be by purification ofthe N-terminally pegylated material from a population of pegylated protein molecules. Selective proteins chemically modified at the N-terminus modification may be accomplished by reductive alkylation which exploits differential reactivity of different types of primary amino groups (lysine versus the N-terminal) available for derivatization in a particular protein. Under the appropriate reaction conditions, substantially selective derivatization ofthe protein at the N-terminus with a carbonyl group containing polymer is achieved. As indicated above, pegylation of the proteins of the invention may be accomplished by any number of means. For example, polyethylene glycol may be attached to the protein either directly or by an intervening linker. Linkerless systems for attaching polyethylene glycol to proteins are described in Delgado et al, Crit. Rev. Thera. Drug Carrier Sys. 9:249-304 (1992); Francis et al, Intern. J. of Hematol 65: 1-18 (1998); U.S. Patent No. 4,002,531 ; U.S. Patent No. 5,349,052; WO 95/06058; and WO 98/32466, the disclosures of each of which are incorporated herein by reference. One system for attaching polyethylene glycol directly to amino acid residues of proteins without an intervening linker employs tresylated MPEG, which is produced by the modification of monmethoxy polyethylene glycol (MPEG) using tresylchloride (ClSO 2 CH,CF 3 ). Upon reaction of protein with tresylated MPEG, polyethylene glycol is directly attached to amine groups ofthe protein. Thus, the invention includes protein-polyethylene glycol conjugates produced by reacting proteins ofthe invention with a polyethylene glycol molecule having a 2,2,2-trifluoreothane sulphonyl group. Polyethylene glycol can also be attached to proteins using a number of different intervening linkers. For example, U.S. Patent No. 5,612,460, the entire disclosure of which is incoφorated herein by reference, discloses urethane linkers for connecting polyethylene glycol to proteins. Protein-polyethylene glycol conjugates wherein the polyethylene glycol is attached to the protein by a linker can also be produced by reaction of proteins with compounds such as MPEG- succinimidylsuccinate, MPEG activated with l,l'-carbonyldiimidazole, MPEG- 2,4,5-trichloropenylcarbonate, MPEG-p-nitrophenolcarbonate, and various MPEG-succinate derivatives. A number additional polyethylene glycol derivatives and reaction chemistries for attaching polyethylene glycol to proteins are described in WO 98/32466, the entire disclosure of which is incorporated herein by reference. Pegylated protein products produced using the reaction chemistries set out herein are included within the scope ofthe invention. The number of polyethylene glycol moieties attached to each protein ofthe invention (i.e., the degree of substitution) may also vary. For example, the pegylated proteins ofthe invention may be linked, on average, to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 17, 20, or more polyethylene glycol molecules. Similarly, the average degree of substitution within ranges such as 1-3, 2-4, 3-5, 4-6, 5-7, 6-8, 7-9, 8-10, 9-1 1 , 10-12, 1 1-13, 12-14, 13-15, 14-16, 15-17, 16-18, 17-19, or 18- 20 polyethylene glycol moieties per protein molecule. Methods for determining the degree of substitution are discussed, for example, in Delgado et al , Crit. Rev Thera Drug Carrier Sys. 9:249-304 (1992). As mentioned the TRID proteins of the invention may be modified by either natural processes, such as posttranslational processing, or by chemical modification techniques which are well known in the art. It will be appreciated that the same type of modification may be present in the same or varying degrees at several sites in a given TRID polypeptide. TRID polypeptides may be branched, for example, as a result of ubiquitination, and they may be cyclic, with or without branching. Cyclic, branched, and branched cyclic TRID polypeptides may result from posttranslation natural processes or may be made by synthetic methods. Modifications include acetylation, acylation, ADP-ribosylation, amidation, covalent attachment of flavin, covalent attachment of a heme moiety, covalent attachment of a nucleotide or nucleotide derivative, covalent attachment of a lipid or lipid derivative, covalent attachment of phosphotidylinositol, cross- linking, cyclization, disulfide bond formation, demethylation, formation of covalent cross-links, formation of cysteine, formation of pyroglutamate, formylation, gamma-carboxylation, glycosylation, GPI anchor formation, hydroxylation, iodination, methylation, myristoylation, oxidation, pegylation, proteolytic processing, phosphorylation, prenylation, racemization, selenoylation, sulfation, transfer-RNA mediated addition of amino acids to proteins such as arginylation, and ubiquitination. (See, for instance, PROTEINS - STRUCTURE AND MOLECULAR PROPERTIES, 2nd Ed., T. E. Creighton, W. H. Freeman and Company, New York (1993); POSTTRANSLATIONAL COVALENT MODIFICATION OF PROTEINS, B. C. Johnson, Ed., Academic Press, New York, pgs. 1-12 (1983); Seifter et al, Meth Enzymol 752:626-646 (1990); Rattan et al , Ann NY Acad Sci 663:48-62 (1992).) Antibodies TRID-protein specific antibodies for use in the present invention can be raised against the intact TRID proteins or an antigenic polypeptide fragment thereof, which may be presented together with a carrier protein, such as an albumin, to an animal system (such as rabbit or mouse) or, if it is long enough (at least about 25 amino acids), without a carrier. The present invention further relates to antibodies and T-cell antigen receptors (TCR) which specifically bind the polypeptides ofthe present invention. The antibodies ofthe present invention include IgG (including IgG 1 , IgG2, IgG3 , and IgG4), IgA (including IgAl and IgA2), IgD, IgE, or IgM, and IgY. As used herein, the term "antibody" (Ab) or "monoclonal antibody" (Mab) is meant to include intact molecules (e.g., whole antibodies), as well as antibody fragments including single-chain whole antibodies, and antigen-binding fragments thereof (such as, for example, Fab and F(ab')2 fragments) which are capable of specifically binding to a TNFR protein. Fab and F(ab')2 fragments lack the Fc fragment of intact antibody, clear more rapidly from the circulation, and may have less non-specific tissue binding of an intact antibody (Wahl et al, J. Nucl. Med. 24:316-325 (1983)). Thus, these fragments are preferred. Most preferably the antibodies are human antigen-binding antibody fragments ofthe present invention and include, but are not limited to, Fab, Fab' and F(ab')2, Fd, single-chain Fvs (scFv), single-chain antibodies, disulfide-linked Fvs (sdFv) and fragments comprising either a V L or V H domain. Antigen-binding antibody fragments, including single-chain antibodies, may comprise the variable region(s) alone or in combination with the entirety or a portion ofthe following: hinge region, CHI, CH2, and CH3 domains. Also included in the invention are antigen-binding fragments also comprising any combination of variable region(s) with a hinge region, CHI, CH2, and CH3 domains. The antibodies of the invention may be from any animal origin including birds and mammals. Preferably, the antibodies are human, murine, donkey, ship rabbit, goat, guinea pig, camel, horse, or chicken. As used herein, "human" antibodies include antibodies having the amino acid sequence of a human immunoglobulin and include antibodies isolated from human immunoglobulin libraries or from animals transgenic for one or more human immunoglobulin and that do not express endogenous immunoglobulins, as described infra and, for example in, U.S. Patent No. 5,939,598 by Kucherlapati et al The antibodies ofthe present invention may be monospecific, bispecific, trispecific or of greater multispecificity. Multispecific antibodies may be specific for different epitopes of a polypeptide ofthe present invention or may be specific for both a polypeptide of the present invention as well as for heterologous compositions, such as a heterologous polypeptide or solid support material. See, e.g., WO 93/17715; WO 92/08802; WO 91/00360; WO 92/05793; Tutt, A. et al. J. Immunol 147:60-69 (1991); US Patents 5,573,920, 4,474,893, 5,601 ,819. 4,714,681. 4,925,648; Kostelny, S.A. et al. J. Immunol. 148: 1541- 553 (1992). Antibodies ofthe present invention may be described or specified in terms ofthe epitope(s) or portion(s) of a polypeptide ofthe present invention which are recognized or specifically bound by the antibody. The epitope(s) or polypeptide portion(s) may be specified as described herein, e.g. , by N-terminal and C-terminal positions, by size in contiguous amino acid residues, or listed in the Tables and Figures. Antibodies which specifically bind any epitope or polypeptide of the present invention may also be excluded. Therefore, the present invention includes antibodies that specifically bind polypeptides ofthe present invention, and allows for the exclusion ofthe same. Antibodies ofthe present invention may also be described or specified in terms of their cross-reactivity. Antibodies that do not bind any other analog, ortholog, or homolog ofthe polypeptides ofthe present invention are included. Antibodies that do not bind polypeptides with less than 95%, less than 90%, less than 85%, less than 80%, less than 75%, less than 70%, less than 65%, less than 60%, less than 55%. and less than 50% identity (as calculated using methods known in the art and described herein) to a polypeptide ofthe present invention are also included in the present invention. Further included in the present invention are antibodies which only bind polypeptides encoded by polynucleotides which hybridize to a polynucleotide of the present invention under stringent hybridization conditions (as described herein) . Antibodies ofthe present invention may also be described or specified in terms of their binding affinity. Preferred binding affinities include those with a dissociation constant or Kd less than 5X10 "2 M, 10 "2 M, 5X10 "3 M, 10 "3 M, 5X10 "4 M, 10 '4 M, 5X10 "5 M, 10 "5 M, 5X10 "6 M, 10 "6 M, 5X10 "7 M, 10 "7 M, 5X10 "8 M, 10 "8 M, 5X10 "9 M, 10 "9 M, 5X10- |ϋ M, 10-'°M, 5X10 " "M, 10 " "M, 5X10 "12 M, 10 " ' 2 M, 5X10 " ' 3 M, 10 " ' M, 5X10 " ' 4 M, 10 "14 M, 5X10 "15 M, and lO "15 M. The invention also provides antibodies that competitively inhibit binding of an antibody to an epitope ofthe invention as determined by any method known in the art for determining competitive binding, for example, the immunoassays described herein. In preferred embodiments, the antibody competitively inhibits binding to the epitope by at least 90%, at least 80%, at least 70%, at least 60%, or at least 50%. Antibodies ofthe present invention may act as agonists, TRAIL binding facilitators, or antagonists of the polypeptides of the present invention. For example, the present invention includes antibodies which disrupt the receptor/ligand interactions with the polypeptides ofthe invention either partially or fully. The invention features both receptor-specific antibodies and ligand-specific antibodies. The invention also features receptor-specific antibodies which do not prevent ligand binding but prevent receptor activation. Receptor activation (i.e., signaling) may be determined by techniques described herein or otherwise known in the art. For example, receptor activation can be determined by detecting the phosphorylation (e.g., tyrosine or serine/threonine) of the receptor or its substrate by immunoprecipitation followed by western blot analysis (for example, as described supra). In specific embodiments, antibodies are provided that inhibit ligand or receptor activity by at least 90%, at least 80%, at least 70%, at least 60%, or at least 50% ofthe activity in absence ofthe antibody. The invention also features receptor-specific antibodies which both prevent ligand binding and receptor activation as well as antibodies that recognize the receptor-ligand complex, and, preferably, do not specifically recognize the unbound receptor or the unbound ligand. Likewise, included in the invention are neutralizing antibodies which bind the ligand and prevent binding ofthe ligand to the receptor, as well as antibodies which bind the ligand, thereby preventing receptor activation, but do not prevent the ligand from binding the receptor. Further included in the invention are antibodies which activate the receptor. These antibodies may act as receptor agonists, i.e., potentiate or activate either all or a subset ofthe biological activities ofthe ligand-mediated receptor activation. The antibodies may be specified as agonists, TRAIL binding facilitators, antagonists or inverse agonists for biological activities comprising the specific biological activities of the peptides of the invention disclosed herein. Thus, the invention further relates to antibodies which act as agonists, TRAIL binding facilitators, or antagonists of the polypeptides of the present invention. The above antibody agonists or TRAIL binding facilitators can be made using methods known in the art. See, e.g., PCT publication WO 96/40281 ; U.S. Patent No. 5,81 1.097; Deng et al, Blood 92 (6) -A 98 - 988 (1998); Chen etal, Cancer Res. 58(1 (5J3668-3678 (1998); Harrop et al, J. Immunol. 161(4):\186- 194 (1998); Zhu et al, Cancer Res. 58(15) :3209-3214 (1998); Yoon et al, J. Immunol. 160(7):3\10-3\19 (1998); Prat et al, J. Cell. Sci. lll(Pt2):231-241 (1998); Pitard et al, J. Immunol. Methods 205(2) : 177- 190 ( 1997); Liautard et al , Cytokine 9(4):233-2 1 (1997); Carlson et al., J Biol. Chem. 272(17):! 1295-1 1301 (1997); Taryman et al, Neuron 14(4):155-162 (1995); Muller et al, Structure 6(9): X 153-1 167 (1998); Bartunek et al, Cytokine 8(l): \4-20 (1996) (which are all incorporated by reference herein in their entireties). Antibodies of the present invention have uses that include, but are not limited to, methods known in the art to purify, detect, and target the polypeptides of the present invention including both in vitro and in vivo diagnostic and therapeutic methods. For example, the antibodies have use in immunoassays for qualitatively and quantitatively measuring levels ofthe polypeptides ofthe present invention in biological samples. See, e.g., Harlow et al., ANTIBODIES: A LABORATORY MANUAL, (Cold Spring Harbor Laboratory Press, 2nd ed. 1988) (incorporated by reference in the entirety). The antibodies of the present invention may be used either alone or in combination with other compositions. The antibodies may further be recombinantly fused to a heterologous polypeptide at the N- or C-terminus or chemically conjugated (including covalently and non-covalently conjugations) to polypeptides or other compositions. For example, antibodies of the present invention may be recombinantly fused or conjugated to molecules useful as labels in detection assays and effector molecules such as heterologous polypeptides, drugs, or toxins. See, e.g., WO 92/08495; WO 91/14438; WO 89/12624; US Patent 5,314,995; and EP 0 396 387. The antibodies ofthe invention include derivatives that are modified, i.e, by the covalent attachment of any type of molecule to the antibody such that covalent attachment does not prevent the antibody from generating an anti-idiotypic response. For example, but not by way of limitation, the antibody derivatives include antibodies that have been modified, e.g.. by glycosylation, acetylation, pegylation, phosphorylation, amidation, derivatization by known protecting/blocking groups, proteolytic cleavage, linkage to a cellular ligand or other protein, etc. Any of numerous chemical modifications may be carried out by known techniques, including, but not limited to specific chemical cleavage, acetylation, formylation, metabolic synthesis of tunicamycin, etc. Additionally, the derivative may contain one or more non-classical amino acids. The antibodies ofthe present invention may be generated by any suitable method known in the art. Polyclonal antibodies to an antigen of interest can be produced by various procedures well known in the art. For example, a polypeptide ofthe invention can be administered to various host animals including, but not limited to, rabbits, mice, rats, etc. to induce the production of sera containing polyclonal antibodies specific for the antigen. Various adjuvants may be used to increase the immunological response, depending on the host species, and include but are not limited to, Freund's (complete and incomplete), mineral gels such as aluminum hydroxide, surface active substances such as lysolecithin, pluronic polyols, polyanions, peptides, oil emulsions, keyhole limpet hemocyanins, dinitrophenol, and potentially useful human adjuvants such as BCG (bacille Calmette-Guerin) and Corynebacterium parvum. Such adjuvants are also well known in the art. In the most preferred method, the antibodies ofthe present invention are monoclonal antibodies. The term "monoclonal antibody" is not a limited to antibodies produced through hybridoma technology. The term "monoclonal antibody" refers to an antibody that is derived from a single clone, including any eukaryotic, prokaryotic, or phage clone, and not the method by which it is produced. Monoclonal antibodies can be prepared using a wide variety of techniques known in the art including the use of hybridoma, recombinant, and phage display technology. For example, monoclonal antibodies can be prepared using hybridoma technology (Kohl ex etal, Nature 256:495 (1975); Kόhler etα/., Ewr. J. Immunol (5:511 ( 1976); Kohleretal., Εur. J. Immunol.6:292 (1976); Hammerling etα/., in: Monoclonal Antibodies and T-Cell Hybridomas, Elsevier, N.Y., (1981) pp. 563-681 ). In general, such procedures involve immunizing an animal (preferably a mouse) with a TRID protein antigen or, more preferably, with a TRID protein-expressing cell. Suitable cells can be recognized by their capacity to bind anti-TRID protein antibody. Such cells may be cultured in any suitable tissue culture medium; however, it is preferable to culture cells in Earle's modified Eagle's medium supplemented with 10% fetal bovine serum (inactivated at about 56° C), and supplemented with about 10 g/1 of nonessential amino acids, about 1,000 U/ml of penicillin, and about 100 μg/ml of streptomycin. The splenocytes of such mice are extracted and fused with a suitable myeloma cell line. Any suitable myeloma cell line may be employed in accordance with the present invention; however, it is preferable to employ the parent myeloma cell line (SP2O), available from the American Type Culture Collection, Rockville, Maryland. After fusion, the resulting hybridoma cells are selectively maintained in HAT medium, and then cloned by limiting dilution as described by Wands et al. (Gastroenterology 50:225-232 (1981)). The hybridoma cells obtained through such a selection are then assayed to identify clones which secrete antibodies capable of binding the desired TRID antigen. Accordingly, the present invention provides methods of generating monoclonal antibodies as well as antibodies produced by the method comprising culturing a hybridoma cell secreting an antibody of the invention wherein, preferably, the hybridoma is generated by fusing splenocytes isolated from a mouse immunized with an antigen ofthe invention with myeloma cells and then screening the hybridomas resulting from the fusion for hybridoma clones that secrete an antibody able to bind a polypeptide ofthe invention. Antibody fragments that recognize specific epitopes may be generated by known techniques. For example, Fab and F(ab')2 fragments ofthe invention may be produced by proteolytic cleavage of immunoglobulin molecules, using enzymes such as papain (to produce Fab fragments) or pepsin (to produce F(ab')2 fragments). F(ab')2 fragments contain the variable region, the light chain constant region and the CHI domain of the heavy chain. Hybridoma techniques include those known in the art and taught in Harlow et al., ANTIBODIES: A LABORATORY MANUAL, (Cold Spring Harbor Laboratory Press, 2nd ed. 1988); Hammerling, et al., in: MONOCLONAL ANTIBODIES AND T-CELL HYBRIDOMAS 563-681 (Elsevier, N.Y., 1981) (said references incorporated by reference in their entireties). It will be appreciated that Fab and F(ab')2 and other fragments ofthe antibodies ofthe present invention may be used according to the methods disclosed herein. Fab and F(ab')2 fragments may be produced by proteolytic cleavage, using enzymes such as papain (to produce Fab fragments) or pepsin (to produce F(ab')2 fragments). Alternatively, TRID protein-binding fragments can be produced through the application of recombinant DNA technology or through synthetic chemistry. Alternatively, additional antibodies capable of binding to the TRID antigen may be produced in a two-step procedure through the use of anti-idiotypic antibodies. Such a method makes use ofthe fact that antibodies are themselves antigens, and that, therefore, it is possible to obtain an antibody which binds to a second antibody. In accordance with this method, TRID-protein specific antibodies are used to immunize an animal, preferably a mouse. The splenocytes of such an animal are then used to produce hybridoma cells, and the hybridoma cells are screened to identify clones which produce an antibody whose ability to bind to the TRID protein-specific antibody can be blocked by the TRID protein antigen. Such antibodies comprise anti-idiotypic antibodies to the TRID protein-specific antibody and can be used to immunize an animal to induce formation of further TRID protein-specific antibodies. For in vivo use of anti-TRID in humans, it may be preferable to use "humanized" chimeric monoclonal antibodies. Such antibodies can be produced using genetic constructs derived from hybridoma cells producing the monoclonal antibodies described above. Methods for producing chimeric antibodies are known in the art. See, for review. Morrison, Science 229:1202 (1985); Oi et al., BioTechniques 4:214 (1986); Cabilly etal., U.S. Patent No.4,816,567; Taniguchi et al., EP 171496; Morrison et al., EP 173494; Neuberger et al., WO 8601533; Robinson et al., WO 8702671 ; Boulianne el al, Nature 312:643 (1984); Neuberger et al, Nature 314:268 (1985). Alternatively, antibodies ofthe present invention can be produced through the application of recombinant DNA and phage display technology or through synthetic chemistry using methods known in the art. For example, the antibodies of the present invention can be prepared using various phage display methods known in the art. In phage display methods, functional antibody domains are displayed on the surface of a phage particle which carries polynucleotide sequences encoding them. Phage with a desired binding property are selected from a repertoire or combinatorial antibody library (e.g. human or murine) by selecting directly with antigen, typically antigen bound or captured to a solid surface or bead. Phage used in these methods are typically filamentous phage including fd and Ml 3 with Fab, Fv or disulfide stabilized Fv antibody domains recombinantly fused to either the phage gene III or gene VIII protein. Examples of phage display methods that can be used to make the antibodies ofthe present invention include those disclosed in Brinkman U. et al J. Immunol Methods 752:41-50 (1995); Ames, R.S. et al J. Immunol. Methods 184:111-186 (1995); Kettleborough, CA. et al. Eur. J. Immunol 24:952-958 (1994); Persic, L. et al Gene 757:9-18 (1997); Burton, D.R. etal Advances in Immunology 57:191-280 (1994); PCT/GB91/01134; WO 90/02809; WO 91/10737; WO 92/01047; WO 92/18619; WO 93/11236; WO 95/15982; WO 95/20401 ; and US Patents 5,698,426, 5,223,409, 5,403,484, 5,580,717, 5,427,908, 5,750,753, 5,821,047, 5,571 ,698, 5,427,908, 5,516,637, 5,780,225, 5,658,727, 5,733,743, and 5,969,108 (said references incoφorated by reference in their entireties). As described in the above references, after phage selection, the antibody coding regions from the phage can be isolated and used to generate whole antibodies, including human antibodies, or any other desired antigen binding fragment, and expressed in any desired host including mammalian cells, insect cells, plant cells, yeast, and bacteria. For example, techniques to recombinantly produce Fab, Fab' and F(ab')2 fragments can also be employed using methods known in the art such as those disclosed in WO 92/22324; Mullinax, R.L. et al. BioTechniques 72(6):864-869 (1992); and Sawai, H. et al AJR154:26-34 (1995); and Better, M. etal. Science 240:1041-1043 (1988) (said references incoφorated by reference in their entireties). Examples of techniques which can be used to produce single-chain Fvs and antibodies include those described in U.S. Patents 4,946,778 and 5,258,498; Huston et al. Methods in Enzymology 205:46-88 (1991); Shu, L. et al. PNAS 90:1995-1999 (1993); and Skerra, A. et al. Science 240:1038-1040 (1988). For some uses, including in vivo use of antibodies in humans and in vitro detection assays, it may be preferable to use chimeric, humanized, or human antibodies. Methods for producing chimeric antibodies are known in the art. See e.g., Morrison, Science 229:1202 (1985); Oi et al, BioTechniques 4:214 (1986); Gillies, S.D. et al. J. Immunol. Methods 725:191-202 (1989); and US Patent 5,807,715. Antibodies can be humanized using a variety of techniques including CDR-grafting (EP 0 239 400; WO 91/09967; US Patent 5,530,101 ; and 5,585,089), veneering or resurfacing (EP 0 592 106; EP 0 519 596; Padlan E.A., Molecular Immunology 25(4/5):489-498 (1991); Studnicka G.M. et al Protein Engineering 7(6):805-814 (1994); Roguska M.A. et al. PNAS 97:969-973 (1994)), and chain shuffling (US Patent 5,565,332). Completely human antibodies are particularly desirable for therapeutic treatment of human patients. Human antibodies can be made by a variety of methods known in the art including phage display methods described above. See also, US Patents 4,444,887, 4,716,1 1 1, 5,545,806, and 5,814,318; and International patent application publication numbers WO 98/46645, WO 98/50433, WO 98/24893, WO 98/16654, WO 96/34096, WO 96/33735, and WO 91/10741 (said references incoφorated by reference in their entireties). Human antibodies can also be produced using transgenic mice which are incapable of expressing functional endogenous immunoglobulins, but which can express human immunoglobulin genes. For example, the human heavy and light chain immunoglobulin gene complexes may be introduced randomly or by homologous recombination into mouse embryonic stem cells. Alternatively, the human variable region, constant region, and diversity region may be introduced into mouse embryonic stem cells in addition to the human heavy and light chain genes. The mouse heavy and light chain immunoglobulin genes may be rendered non-functional separately or simultaneously with the introduction of human immunoglobulin loci by homologous recombination. In particular, homozygous deletion ofthe JH region prevents endogenous antibody production. The modified embryonic stem cells are expanded and microinjected into blastocysts to produce chimeric mice. The chimeric mice are then bred to produce homozygous offspring that express human antibodies. The transgenic mice are immunized in the normal fashion with a selected antigen, e.g., all or a portion of a polypeptide of the invention. Monoclonal antibodies directed against the antigen can be obtained from the immunized, transgenic mice using conventional hybridoma technology. The human immunoglobulin transgenes harbored by the transgenic mice rearrange during B-cell differentiation, and subsequently undergo class switching and somatic mutation. Thus, using such a technique, it is possible to produce therapeutically useful IgG, IgA, IgM and IgE antibodies. For an overview of this technology for producing human antibodies, see Lonberg and Huszar (1995, Int. Rev. Immunol. 13:65-93). For a detailed discussion of this technology for producing human antibodies and human monoclonal antibodies and protocols for producing such antibodies, see, e.g., PCT publications WO 98/24893; WO 96/34096; WO 96/33735; U.S. Patent Nos. 5,413,923; 5,625,126; 5,633,425; 5,569,825; 5,661,016; 5,545,806; 5,814,318; and 5,939,598, which are incorporated by reference herein in their entirety. In addition, companies such as Abgenix, Inc. (Freemont, CA) and GenPharm (San Jose, CA) can be engaged to provide human antibodies directed against a selected antigen using technology similar to that described above. Completely human antibodies which recognize a selected epitope can be generated using a technique referred to as "guided selection." In this approach a selected non-human monoclonal antibody, e.g. , a mouse antibody, is used to guide the selection of a completely human antibody recognizing the same epitope. (Jespers et αl, Bio/ technology 72:899-903 (1988)). As discussed above, antibodies to the TRID proteins ofthe invention can, in turn, be utilized to generate anti-idiotype antibodies that "mimic" TRID using techniques well known to those skilled in the art. (See, e.g., Greenspan & Bona, FASEB J. 7(5):437-444; (1989) and Nissinoff, J. Immunol. 747(8):2429-2438 (1991)). For example, antibodies which bind to TRID and competitively inhibit TRID multimerization and/or binding to ligand can be used to generate anti- idiotypes that "mimic" the TRID mutimerization and/or binding domain and, as a consequence, bind to and neutralize TRID and/or its ligand. Such neutralizing anti-idiotypes or Fab fragments of such anti-idiotypes can be used in therapeutic regimens to neutralize TRID ligand. For example, such anti-idiotypic antibodies can be used to bind TRID, or to bind TRID ligands/receptors, and thereby block TRID mediated inhibition of apoptosis. Further included in the present invention are antibodies recombinantly fused or chemically conjugated (including both covalently and non-covalently conjugations) to a polypeptide ofthe present invention. The antibodies may be specific for antigens other than polypeptides of the present invention. For example, antibodies may be used to target the polypeptides of the present invention to particular cell types, either in vitro or in vivo, by fusing or conjugating the polypeptides of the present invention to antibodies specific for particular cell surface receptors. Antibodies fused or conjugated to the polypeptides ofthe present invention may also be used in in vitro immunoassays and purification methods using methods known in the art. See e.g. , Harbor et αl. supra and WO 93/21232; EP 0 439 095; Naramura, M. et al. Immunol. ett. 59:91-99 (1994); US Patent 5,474,981 ; Gillies, S.O. et al. PNAS 59: 1428-1432 (1992); Fell, H.P. et al. J. Immunol 146:2446-2452 (1991) (said references incorporated by reference in their entireties). The present invention further includes compositions comprising, or alternatively consisting of, TRID polypeptides ofthe present invention fused or conjugated to antibody domains other than the variable regions. For example, the polypeptides ofthe present invention may be fused or conjugated to an antibody Fc region, or portion thereof. The antibody portion fused to a polypeptide ofthe present invention may comprise the hinge region, CH 1 domain, CH2 domain, and CH3 domain or any combination of whole domains or portions thereof. The polypeptides of the present invention may be fused or conjugated to the above antibody portions to increase the in vivo half life ofthe polypeptides or for use in immunoassays using methods known in the art. The polypeptides may also be fused or conjugated to the above antibody portions to form multimers. For example, Fc portions fused to the polypeptides ofthe present invention can form dimers through disulfide bonding between the Fc portions. Higher multimeric forms can be made by fusing the polypeptides to portions of IgA and IgM. Methods for fusing or conjugating the polypeptides of the present invention to antibody portions are known in the art. See e.g., US Patents 5,336,603, 5,622,929, 5,359,046, 5,349,053, 5,447,851, 5,112,946; EP 0 307434, EP 0 367 166; WO 96/04388, WO 91/06570; Ashkenazi, A. et al. PNAS 55: 10535-10539 (1991); Zheng, X.X. et al. J. Immunol 754:5590-5600 (1995); and Nil, H. et al. PNAS 59: 1 1337- 11341 (1992) (said references incorporated by reference in their entireties). In addition, the present invention includes antibodies which disrupt the ability of the proteins ofthe invention to multimerize. In another example, the present invention includes antibodies which allow the proteins ofthe invention to multimerize, but disrupts the ability ofthe proteins ofthe invention to bind one or more TRID receptor(s)/ligand(s) (e.g., TRAIL). In yet another example, the present invention includes antibodies which allow the proteins ofthe invention to multimerize. and bind TRID receptor(s)/ligand(s) (e.g., TRAIL), but blocks biological activity associated with the TRID/receptor/ligand complex. A. Polynucleotides Encoding Antibodies. The invention further provides polynucleotides comprising a nucleotide sequence encoding an antibody of the invention and fragments thereof. The invention also encompasses polynucleotides that hybridize under stringent or lower stringency hybridization conditions, e.g., as defined supra, to polynucleotides that encode an antibody, preferably, that specifically binds to a polypeptide ofthe invention, preferably, an antibody that binds to a polypeptide having the amino acid sequence of SEQ ID NO:2. The polynucleotides may be obtained, and the nucleotide sequence ofthe polynucleotides determined, by any method known in the art. For example, if the nucleotide sequence of the antibody is known, a polynucleotide encoding the antibody may be assembled from chemically synthesized oligonucleotides (e.g., as described in Kutmeier et al. BioTechniques 77:242 (1994)), which, briefly, involves the synthesis of overlapping oligonucleotides containing portions ofthe sequence encoding the antibody, annealing and ligation of those oligonucleotides, and then amplification of the ligated oligonucleotides by PCR. Alternatively, a polynucleotide encoding an antibody may be generated from nucleic acid from a suitable source. If a clone containing a nucleic acid encoding a particular antibody is not available, but the sequence ofthe antibody molecule is known, a nucleic acid encoding the immunoglobulin may be obtained from a suitable source (e.g., an antibody cDNA library, or a cDNA library generated from, or nucleic acid, preferably poly A+ RNA, isolated from, any tissue or cells expressing the antibody, such as hybridoma cells selected to express an antibody of the invention) by PCR amplification using synthetic primers hybridizable to the 3' and 5' ends of the sequence or by cloning using an oligonucleotide probe specific for the particular gene sequence to identify, e.g. , a cDNA clone from a cDNA library that encodes the antibody. Amplified nucleic acids generated by PCR may then be cloned into replicable cloning vectors using any method well known in the art. Once the nucleotide sequence and corresponding amino acid sequence of the antibody is determined, the nucleotide sequence of the antibody may be manipulated using methods well known in the art for the manipulation of nucleotide sequences, e.g., recombinant DNA techniques, site directed mutagenesis, PCR, etc. (see, for example, the techniques described in Sambrook et al, 1990, Molecular Cloning, A Laboratory Manual, 2d Ed., Cold Spring Harbor Laboratory, Cold Spring Harbor, NY and Ausubel et al, eds., 1998. Current Protocols in Molecular Biology, John Wiley & Sons, NY, which are both incoφorated by reference herein in their entireties), to generate antibodies having a different amino acid sequence, for example to create amino acid substitutions, deletions, and/or insertions. In a specific embodiment, the amino acid sequence of the heavy and/or light chain variable domains may be inspected to identify the sequences of the complementarity determining regions (CDRs) by methods that are well know in the art, e.g. , by comparison to known amino acid sequences of other heavy and light chain variable regions to determine the regions of sequence hypervariability. Using routine recombinant DNA techniques, one or more of the CDRs may be inserted within framework regions, e.g., into human framework regions to humanize a non-human antibody, as described supra. The framework regions may be naturally occurring or consensus framework regions, and preferably human framework regions (see, e.g., Chothia etα/.,J Mol Biol. 275:457-479 (1998) for a listing of human framework regions). Preferably, the polynucleotide generated by the combination ofthe framework regions and CDRs encodes an antibody that specifically binds a polypeptide ofthe invention. Preferably, as discussed supra, one or more amino acid substitutions may be made within the framework regions, and, preferably, the amino acid substitutions improve binding ofthe antibody to its antigen. Additionally, such methods may be used to make amino acid substitutions or deletions of one or more variable region cysteine residues participating in an intrachain disulfide bond to generate antibody molecules lacking one or more intrachain disulfide bonds. Other alterations to the polynucleotide are encompassed by the present invention and within the skill of the art. In addition, techniques developed for the production of "chimeric antibodies" (Morrison et al , 1984, Proc. Natl. Acad. Sci. 57:851-855; Neuberger et al, 1984, Nature 572:604-608; Takeda et al, 1985, Nature 574:452-454) by splicing genes from a mouse antibody molecule of appropriate antigen specificity together with genes from a human antibody molecule of appropriate biological activity can be used. As described supra, a chimeric antibody is a molecule in which different portions are derived from different animal species, such as those having a variable region derived from a murine monoclonal antibody and a human immunoglobulin constant region, e.g., humanized antibodies. Alternatively, techniques described for the production of single chain antibodies (U.S. Patent No. 4,694,778; Bird, 1988, Science 242:423-42; Huston et al, 1988, Proc. Natl Acad. Sci. USA 55:5879-5883; and Ward et al, 1989, Nature 554:544-554) can be adapted to produce single chain antibodies. Single chain antibodies are formed by linking the heavy and light chain fragments ofthe Fv region via an amino acid bridge, resulting in a single chain polypeptide. Techniques for the assembly of functional Fv fragments in E. coli may also be used (Skerra et al, 1988, Science 242:1038- 1041). B. Methods of Producing Antibodies The antibodies ofthe invention can be produced by any method known in the art for the synthesis of antibodies, in particular, by chemical synthesis or preferably, by recombinant expression techniques. Recombinant expression of an antibody of the invention, or fragment, derivative or analog thereof, e.g., a heavy or light chain of an antibody of the invention, requires construction of an expression vector containing a polynucleotide that encodes the antibody. Once a polynucleotide encoding an antibody molecule or a heavy or light chain of an antibody, or portion thereof (preferably containing the heavy or light chain variable domain), ofthe invention has been obtained, the vector for the production ofthe antibody molecule may be produced by recombinant DNA technology using techniques well known in the art. Thus, methods for preparing a protein by expressing a polynucleotide containing an antibody encoding nucleotide sequence are described herein. Methods which are well known to those skilled in the art can be used to construct expression vectors containing antibody coding sequences and appropriate transcriptional and translational control signals. These methods include, for example, in vitro recombinant DNA techniques, synthetic techniques, and in vivo genetic recombination. The invention, thus, provides replicable vectors comprising a nucleotide sequence encoding an antibody molecule ofthe invention, or a heavy or light chain thereof, or a heavy or light chain variable domain, operably linked to a promoter. Such vectors may include the nucleotide sequence encoding the constant region ofthe antibody molecule (see, e.g. , PCT Publication WO 86/05807; PCT Publication WO 89/01036; and U.S. Patent No. 5,122,464) and the variable domain of the antibody may be cloned into such a vector for expression of the entire heavy or light chain. The expression vector is transferred to a host cell by conventional techniques and the transfected cells are then cultured by conventional techniques to produce an antibody ofthe invention. Thus, the invention includes host cells containing a polynucleotide encoding an antibody ofthe invention, or a heavy or light chain thereof, operably linked to a heterologous promoter. In preferred embodiments for the expression of double-chained antibodies, vectors encoding both the heavy and light chains may be co-expressed in the host cell for expression of the entire immunoglobulin molecule, as detailed below. A variety of host-expression vector systems may be utilized to express the antibody molecules of the invention. Such host-expression systems represent vehicles by which the coding sequences of interest may be produced and subsequently purified, but also represent cells which may, when transformed or transfected with the appropriate nucleotide coding sequences, express an antibody molecule of the invention in situ. These include but are not limited to microorganisms such as bacteria (e.g., E. coli, B. subtilis) transformed with recombinant bacteriophage DNA, plasmid DNA or cosmid DNA expression vectors containing antibody coding sequences; yeast (e.g., Saccharomyces, Pichia) transformed with recombinant yeast expression vectors containing antibody coding sequences; insect cell systems infected with recombinant virus expression vectors (e.g. , baculovirus) containing antibody coding sequences; plant cell systems infected with recombinant virus expression vectors (e.g. , cauliflower mosaic virus, CaMV; tobacco mosaic virus, TMV) or transformed with recombinant plasmid expression vectors (e.g., Ti plasmid) containing antibody coding sequences; or mammalian cell systems (e.g., COS, CHO, BHK, 293, 3T3 cells) harboring recombinant expression constructs containing promoters derived from the genome of mammalian cells (e.g. , metallothionein promoter) or from mammalian viruses (e.g., the adenovirus late promoter; the vaccinia virus 7.5K promoter). Preferably, bacterial cells such as Escherichia coli, and more preferably, eukaryotic cells, especially for the expression of whole recombinant antibody molecule, are used for the expression of a recombinant antibody molecule. For example, mammalian cells such as Chinese hamster ovary cells (CHO), in conjunction with a vector such as the major intermediate early gene promoter element from human cytomegalovirus is an effective expression system for antibodies (Foecking et al, 1986, Gene 45:101 ; Cockett et al , 1990, Bio/Technology 5:2). In bacterial systems, a number of expression vectors may be advantageously selected depending upon the use intended for the antibody molecule being expressed. For example, when a large quantity of such a protein is to be produced, for the generation of pharmaceutical compositions of an antibody molecule, vectors which direct the expression of high levels of fusion protein products that are readily purified may be desirable. Such vectors include, but are not limited, to the E. coli expression vector pUR278 (Ruther et al, 1983, EMBO J. 2:1791), in which the antibody coding sequence may be ligated individually into the vector in frame with the lac Z coding region so that a fusion protein is produced; pIN vectors (Inouye & Inouye, 1985, Nucleic Acids Res. 75:3101-3109; Van Heeke & Schuster, 1989, J Biol Chem. 24:5503-5509); and the like. pGEX vectors may also be used to express foreign polypeptides as fusion proteins with glutathione S-transferase (GST). In general, such fusion proteins are soluble and can easily be purified from lysed cells by adsoφtion and binding to a matrix glutathione-agarose beads followed by elution in the presence of free glutathione. The pGEX vectors are designed to include thrombin or factor Xa protease cleavage sites so that the cloned target gene product can be released from the GST moiety. In an insect system. Autographa californica nuclear polyhedrosis virus (AcNPV) is used as a vector to express foreign genes. The virus grows in Spodoptera frugiperda cells. The antibody coding sequence may be cloned individually into non-essential regions (for example the polyhedrin gene) ofthe virus and placed under control of an AcNPV promoter (for example the polyhedrin promoter). In mammalian host cells, a number of viral-based expression systems may be utilized. In cases where an adenovirus is used as an expression vector, the antibody coding sequence of interest may be ligated to an adenovirus transcription/translation control complex, e.g. , the late promoter and tripartite leader sequence. This chimeric gene may then be inserted in the adenovirus genome by in vitro or in vivo recombination. Insertion in a non- essential region ofthe viral genome (e.g. , region El or E3) will result in a recombinant virus that is viable and capable of expressing the antibody molecule in infected hosts, (e.g. , see Logan & Shenk, 1984, Proc. Natl. Acad. Sci. USA 57:355-359). Specific initiation signals may also be required for efficient translation of inserted antibody coding sequences. These signals include the ATG initiation codon and adjacent sequences. Furthermore, the initiation codon must be in phase with the reading frame of the desired coding sequence to ensure translation of the entire insert. These exogenous translational control signals and initiation codons can be of a variety of origins, both natural and synthetic. The efficiency of expression may be enhanced by the inclusion of appropriate transcription enhancer elements, transcription terminators, etc. (see Bittner et al, 1987, Methods in Enzymol 755:51-544). In addition, a host cell strain may be chosen which modulates the expression ofthe inserted sequences, or modifies and processes the gene product in the specific fashion desired. Such modifications (e.g., glycosylation) and processing (e.g. , cleavage) of protein products may be important for the function ofthe protein. Different host cells have characteristic and specific mechanisms for the post-translational processing and modification of proteins and gene products. Appropriate cell lines or host systems can be chosen to ensure the correct modification and processing of the foreign protein expressed. To this end, eukaryotic host cells which possess the cellular machinery for proper processing ofthe primary transcript, glycosylation, and phosphorylation ofthe gene product may be used. Such mammalian host cells include but are not limited to CHO, VERY, BHK, HeLa, COS, MDCK, 293, 3T3, WI38, and in particular, breast cancer cell lines such as, for example, BT483, Hs578T, HTB2, BT20 and T47D, and normal mammary gland cell line such as, for example, CRL7030 and Hs578Bst. For long-term, high-yield production of recombinant proteins, stable expression is preferred. For example, cell lines which stably express the antibody molecule may be engineered. Rather than using expression vectors which contain viral origins of replication, host cells can be transformed with DNA controlled by appropriate expression control elements (e.g. , promoter, enhancer, sequences, transcription terminators, polyadenylation sites, etc.), and a selectable marker. Following the introduction ofthe foreign DNA, engineered cells may be allowed to grow for 1-2 days in an enriched media, and then are switched to a selective media. The selectable marker in the recombinant plasmid confers resistance to the selection and allows cells to stably integrate the plasmid into their chromosomes and grow to form foci which in turn can be cloned and expanded into cell lines. This method may advantageously be used to engineer cell lines which express the antibody molecule. Such engineered cell lines may be particularly useful in screening and evaluation of compounds that interact directly or indirectly with the antibody molecule. A number of selection systems may be used, including but not limited to the heφes simplex virus thymidine kinase (Wigler et al, 1977, Cell 77:223), hypoxanthine-guanine phosphoribosyltransferase (Szybalska & Szybalski, 192, Proc. Natl Acad. Sci. USA 48:202), and adenine phosphoribosyltransferase (Lowy et al , 1980, Cell 22:817) genes can be employed in tk-, hgprt- or aprt- cells, respectively. Also, antimetabolite resistance can be used as the basis of selection for the following genes: dhfr, which confers resistance to methotrexate (Wigler et al , 1980, Natl. Acad. Sci. USA 77:357; O'Hare et al, 1981, Proc. Natl. Acad. Sci. USA 78: 1527); gpt, which confers resistance to mycophenolic acid (Mulligan & Berg, 1981. Proc. Natl. Acad. Sci. USA 78:2072); neo, which confers resistance to the aminoglycoside G-418 Clinical Pharmacy 12:488-505; Wu and Wu, 1991, Biotherapy 3:87-95; Tolstoshev, 1993, Ann. Rev. Pharmacol. Toxicol. 32:573-596; Mulligan, 1993, Science 260:926-932; and Morgan and Anderson, 1993, Ann. Rev. Biochem. 62: 191-217; May, 1993, TIB TECH 11 (5): 155-215); and hygro, which confers resistance to hygromycin (Santerre et al, 1984, Gene 30: 147). Methods commonly known in the art of recombinant DNA technology which can be used are described in Ausubel et al. (eds.), 1993, Current Protocols in Molecular Biology. John Wiley & Sons, NY; Kriegler, 1990, Gene Transfer and Expression, A Laboratory Manual, Stockton Press, NY; and in Chapters 12 and 13. Dracopoli et al. (eds), 1994, Current Protocols in Human Genetics, John Wiley & Sons, NY.; Colberre-Garapin et al. , 1981 , J. Mol Biol 750:1 , which are incoφorated by reference herein in their entireties. The expression levels of an antibody molecule can be increased by vector amplification (for a review, see Bebbington and Hentschel, The use of vectors based on gene amplification for the expression of cloned genes in mammalian cells in DNA cloning, Vol. 3. (Academic Press, New York, 1987)). When a marker in the vector system expressing antibody is amplifiable, increase in the level of inhibitor present in culture of host cell will increase the number of copies ofthe marker gene. Since the amplified region is associated with the antibody gene, production ofthe antibody will also increase (Crouse et al . 1983, Mol. Cell. Biol. 5:257). The host cell may be co-transfected with two expression vectors of the invention, the first vector encoding a heavy chain derived polypeptide and the second vector encoding a light chain derived polypeptide. The two vectors may contain identical selectable markers which enable equal expression of heavy and light chain polypeptides. Alternatively, a single vector may be used which encodes both heavy and light chain polypeptides. In such situations, the light chain should be placed before the heavy chain to avoid an excess of toxic free heavy chain (Proudfoot, 1986, Nature 322:52; Kohler, 1980. Proc. Natl Acad. Sci. USA 77:2197). The coding sequences for the heavy and light chains may comprise cDNA or genomic DNA. Once an antibody molecule of the invention has been recombinantly expressed, it may be purified by any method known in the art for purification of an immunoglobulin molecule, for example, by chromatography (e.g., ion exchange, affinity, particularly by affinity for the specific antigen after Protein A, and sizing column chromatography), centrifugation, differential solubility, or by any other standard technique for the purification of proteins. C. Antibody Conjugates The present invention encompasses antibodies recombinantly fused or chemically conjugated (including both covalently and non-covalently conjugations) to a polypeptide (or portion thereof, preferably at least 10, 20 or 50 amino acids of the polypeptide) of the present invention to generate fusion proteins. The fusion does not necessarily need to be direct, but may occur through linker sequences. The antibodies may be specific for antigens other than polypeptides (or portion thereof, preferably at least 10, 20 or 50 amino acids of the polypeptide) of the present invention. For example, antibodies may be used to target the polypeptides ofthe present invention to particular cell types, either in vitro or in vivo, by fusing or conjugating the polypeptides ofthe present invention to antibodies specific for particular cell surface receptors. Antibodies fused or conjugated to the polypeptides of the present invention may also be used in in vitro immunoassays and purification methods using methods known in the art. See e.g., Harbor et al , supra, and PCT publication WO 93/21232; EP 439,095; v mm et al., Immunol. Lett. 59:91-99 (1994); U.S. Patent 5,474,981 ; Gillies et al, PNAS 59: 1428-1432 (1992); Fell et al, J. Immunol. 146:2446-2452 (1991), which are incoφorated by reference in their entireties. The present invention further includes compositions comprising the polypeptides of the present invention fused or conjugated to antibody domains other than the variable regions. For example, the polypeptides of the present invention may be fused or conjugated to an antibody Fc region, or portion thereof. The antibody portion fused to a polypeptide ofthe present invention may comprise the constant region, hinge region, CHI domain, CH2 domain, and CH3 domain or any combination of whole domains or portions thereof. The polypeptides may also be fused or conjugated to the above antibody portions to form multimers. For example, Fc portions fused to the polypeptides ofthe present invention can form dimers through disulfide bonding between the Fc portions. Higher multimeric forms can be made by fusing the polypeptides to portions of IgA and IgM. Methods for fusing or conjugating the polypeptides ofthe present invention to antibody portions are known in the art. See, e.g., U.S. Patent Nos. 5,336,603; 5,622,929; 5,359,046; 5,349.053; 5,447,851 ; 5,1 12,946; EP 307,434; EP 367,166; PCT publications WO 96/04388; WO 91/06570; Ashkenazi etal, Proc. Natl. Acad. Sci. USA 88: 10535-10539 (1991); Zheng et al, J. Immunol. 154:5590-5600 (1995); and Vil et al, Proc. Natl. Acad. Sci. USA 89: 11337- 11341(1992) (said references incoφorated by reference in their entireties). As discussed, supra, the polypeptides of the present invention may be fused or conjugated to the above antibody portions to increase the in vivo half life ofthe polypeptides or for use in immunoassays using methods known in the art. Further, the polypeptides ofthe present invention may be fused or conjugated to the above antibody portions to facilitate purification. One reported example describes chimeric proteins consisting of the first two domains of the human CD4-polypeptide and various domains ofthe constant regions ofthe heavy or light chains of mammalian immunoglobulins. (EP 394,827; Traunecker et al. , Nature 331 :84-86 (1988). The polypeptides ofthe present invention fused or conjugated to an antibody having disulfide- linked dimeric structures (due to the IgG) may also be more efficient in binding and neutralizing other molecules, than the monomeric secreted protein or protein fragment alone. (Fountoulakis et al , J. Biochem. 270:3958-3964 (1995)). In many cases, the Fc part in a fusion protein is beneficial in therapy and diagnosis, and thus can result in, for example, improved pharmacokinetic properties. (EP A 232,262). Alternatively, deleting the Fc part after the fusion protein has been expressed, detected, and purified, would be desired. For example, the Fc portion may hinder therapy and diagnosis if the fusion protein is used as an antigen for immunizations. In drug discovery, for example, human proteins, such as hIL-5 receptor, have been fused with Fc portions for the puφose of high-throughput screening assays to identify antagonists of hIL-5. (See, D. Bennett et al, J. Molecular Recognition 5:52-58 (1995); K. Johanson et α/., J Biol. Chem. 270:9459-9471 (1995). Moreover, the antibodies or fragments thereof of the present invention can be fused to marker sequences, such as a peptide to facilitates their purification. In preferred embodiments, the marker amino acid sequence is a hexa-histidine peptide, such as the tag provided in a pQE vector (QIAGEN, Inc., 9259 Eton Avenue, Chatsworth, C A, 9131 1), among others, many of which are commercially available. As described in Gentz et al, Proc. Natl. Acad. Sci. USA 5(5:821-824 (1989), for instance, hexa-histidine provides for convenient purification of the fusion protein. Other peptide tags useful for purification include, but are not limited to, the "HA" tag, which corresponds to an epitope derived from the influenza hemagglutinin protein (Wilson et al. , Cell 37: 767 ( 1984)) and the "flag" tag. The present invention further encompasses antibodies or fragments thereof conjugated to a diagnostic or therapeutic agent. The antibodies can be used diagnostically to, for example, monitor the development or progression of a tumor as part of a clinical testing procedure to, e.g., determine the efficacy of a given treatment and/or prevention regimens. Detection can be facilitated by coupling the antibody to a detectable substance. Examples of detectable substances include various enzymes, prosthetic groups, fluorescent materials, luminescent materials, bioluminescent materials, radioactive materials, positron emitting metals using various positron emission tomographies, and nonradioactive paramagnetic metal ions. See, for example, U.S. Patent No. 4,741,900 for metal ions which can be conjugated to antibodies for use as diagnostics according to the present invention. Examples of suitable enzymes include horseradish peroxidase, alkaline phosphatase, β-galactosidase, or acetylcholinesterase; examples of suitable prosthetic group complexes include streptavidin/biotin and avidin/biotin; examples of suitable fluorescent materials include umbelliferone, fluorescein, fluorescein isothiocyanate, rhodamine, dichlorotriazinylamine fluorescein, dansyl chloride or phycoerythrin; an example of a luminescent material includes luminol; examples of bioluminescent materials include luciferase. luciferin, and aequorin; and examples of suitable radioactive material include 125 I, ljl I, '"In or "Tc. Further, an antibody or fragment thereof may be conjugated to a therapeutic moiety such as a cyto toxin, e.g., a cytostatic or cytocidal agent, a therapeutic agent or a radioactive metal ion. A cytotoxin or cytotoxic agent includes any agent that is detrimental to cells. Examples include paclitaxol, cytochalasin B, gramicidin D, ethidium bromide, emetine, mitomycin, etoposide, tenoposide, vincristine, vinblastine, colchicin, doxorubicin, daunorubicin, dihydroxy anthracin dione, mitoxantrone, mithramycin, actinomycin D, 1 -dehydrotestosterone, glucocorticoids, procaine, tetracaine, lidocaine, propranolol, and puromycin and analogs or homologs thereof. Therapeutic agents include, but are not limited to, antimetabolites (e.g., methotrexate, 6-mercaptopurine, 6-thioguanine, cytarabine, 5-fluorouracil decarbazine), alkylating agents (e.g., mechlorethamine, thioepa chlorambucil, melphalan, carmustine (BSNU) and lomustine (CCNU), cyclothosphamide, busulfan, dibromomannitol, streptozotocin, mitomycin C, and c/s-dichlorodiamine platinum (II) (DDP) cisplatin), anthracyclines (e.g., daunorubicin (formerly daunomycin) and doxorubicin), antibiotics (e.g., dactinomycin (formerly actinomycin), bleomycin, mithramycin, and anthramycin (AMC)), and anti-mitotic agents (e.g. , vincristine and vinblastine). The conjugates of the invention can be used for modifying a given biological response, the therapeutic agent or drug moiety is not to be construed as limited to classical chemical therapeutic agents. For example, the drug moiety may be a protein or polypeptide possessing a desired biological activity. Such proteins may include, for example, a toxin such as abrin, ricin A, pseudomonas exotoxin, or diphtheria toxin; a protein such as tumor necrosis factor, a-interferon, β-interferon, nerve growth factor, platelet derived growth factor, tissue plasminogen activator, a thrombotic agent or an anti-angiogenic agent, e.g., angiostatin or endostatin; or, biological response modifiers such as, for example, lymphokines, interleukin-1 ("IL-1 "), interleukin-2 ("IL-2"), interleukin-6 ("IL-6"), granulocyte macrophase colony stimulating factor ("GM-CSF"), granulocyte colony stimulating factor ("G-CSF"), or other growth factors. Antibodies may also be attached to solid supports, which are particularly useful for immunoassays or purification ofthe target antigen. Such solid supports include, but are not limited to, glass, cellulose, polyacrylamide, nylon, polystyrene, poly vinyl chloride or polypropylene. Techniques for conjugating such therapeutic moiety to antibodies are well known, see, e.g. , Arnon et al. , "Monoclonal Antibodies For Immunotargeting Of Drugs In Cancer Therapy", in Monoclonal Antibodies And Cancer Therapy, Reisfeld et al (eds.), pp. 243-56 (Alan R. Liss, Inc. 1985); Hellstrom et al, "Antibodies For Drug Delivery", in Controlled Drug Delivery (2nd Ed.), Robinson et al (eds.), pp. 623-53 (Marcel Dekker, Inc. 1987); Thoφe, "Antibody Carriers Of Cytotoxic Agents In Cancer Therapy: A Review", in Monoclonal Antibodies '84: Biological And Clinical Applications, Pinchera et al. (eds.), pp. 475-506 (1985); "Analysis, Results, And Future Prospective Of The Therapeutic Use Of Radiolabeled Antibody In Cancer Therapy", in Monoclonal Antibodies For Cancer Detection And Therapy, Baldwin et al. (eds.), pp. 303-16 (Academic Press 1985), and Thoφe et al, "The Preparation And Cytotoxic Properties Of Antibody-Toxin Conjugates", Immunol. Rev. 52:119-58 (1982). - I l l - Alternatively, an antibody can be conjugated to a second antibody to form an antibody heteroconjugate as described by Segal in U.S. Patent No. 4,676,980, which is incorporated herein by reference in its entirety. An antibody, with or without a therapeutic moiety conjugated to it, administered alone or in combination with cytotoxic factor(s) and/or cytokine(s) can be used as a therapeutic. D. Assays For Antibody Binding The antibodies ofthe invention may be assayed for immunospecific binding by any method known in the art. The immunoassays which can be used include but are not limited to competitive and non-competitive assay systems using techniques such as western blots, radioimmunoassays, ELISA (enzyme linked immunosorbent assay), "sandwich" immunoassays, immunoprecipitation assays, precipitin reactions, gel diffusion precipitin reactions, immunodiffusion assays, agglutination assays, complement-fixation assays, immunoradiometric assays, fluorescent immunoassays, protein A immunoassays, to name but a few. Such assays are routine and well known in the art (see, e.g., Ausubel et al, eds, 1994, Current Protocols in Molecular Biology, Vol. 1, John Wiley & Sons, Inc., New York, which is incoφorated by reference herein in its entirety). Exemplary immunoassays are described briefly below (but are not intended by way of limitation). Immunoprecipitation protocols generally comprise lysing a population of cells in a lysis buffer such as RIPA buffer ( 1 % NP-40 or Triton X- 100, 1 % sodium deoxycholate, 0.1% SDS, 0.15 M NaCl, 0.01 M sodium phosphate atpH 7.2, 1% Trasylol) supplemented with protein phosphatase and/or protease inhibitors (e.g. , EDTA, PMSF, aprotinin, sodium vanadate), adding the antibody of interest to the cell lysate, incubating for a period of time (e.g. , 1 -4 hours) at 4° C, adding protein A and/or protein G sepharose beads to the cell lysate, incubating for about an hour or more at 4° C, washing the beads in lysis buffer and resuspending the beads in SDS/sample buffer. The ability ofthe antibody of interest to immunoprecipitate a particular antigen can be assessed by, e.g. , western blot analysis. One of skill in the art would be knowledgeable as to the parameters that can be modified to increase the binding ofthe antibody to an antigen and decrease the background (e.g., pre-clearing the cell lysate with sepharose beads). For further discussion regarding immunoprecipitation protocols see, e.g., Ausubel et al., eds, 1994, Current Protocols in Molecular Biology, Vol. 1, John Wiley & Sons, Inc., New York at 10.16.1. Western blot analysis generally comprises preparing protein samples, electrophoresis of the protein samples in a polyacrylamide gel (e.g., 8%-20% SDS-PAGE depending on the molecular weight ofthe antigen), transferring the protein sample from the polyacrylamide gel to a membrane such as nitrocellulose. PVDF or nylon, blocking the membrane in blocking solution (e.g. , PBS with 3% BSA or non-fat milk), washing the membrane in washing buffer (e.g. , PBS-Tween 20), blocking the membrane with primary antibody (the antibody of interest) diluted in blocking buffer, washing the membrane in washing buffer, blocking the membrane with a secondary antibody (which recognizes the primary antibody, e.g., an anti-human antibody) conjugated to an enzymatic substrate (e.g., horseradish peroxidase or alkaline phosphatase) or radioactive molecule (e.g. , 32 P or ,25 I) diluted in blocking buffer, washing the membrane in wash buffer, and detecting the presence of the antigen. One of skill in the art would be knowledgeable as to the parameters that can be modified to increase the signal detected and to reduce the background noise. For further discussion regarding western blot protocols see, e.g., Ausubel et al, eds, 1994, Current Protocols in Molecular Biology, Vol. 1, John Wiley & Sons, Inc., New York at 10.8.1. ELISAs comprise preparing antigen, coating the well of a 96 well microtiter plate with the antigen, adding the antibody of interest conjugated to a detectable compound such as an enzymatic substrate (e.g.. horseradish peroxidase or alkaline phosphatase) to the well and incubating for a period of time, and detecting the presence ofthe antigen. In ELISAs the antibody of interest does not have to be conjugated to a detectable compound; instead, a second antibody (which recognizes the antibody of interest) conjugated to a detectable compound may be added to the well. Further, instead of coating the well with the antigen, the antibody may be coated to the well. In this case, a second antibody conjugated to a detectable compound may be added following the addition ofthe antigen of interest to the coated well. One of skill in the art would be knowledgeable as to the parameters that can be modified to increase the signal detected as well as other variations of ELISAs known in the art. For further discussion regarding ELISAs see, e.g. , Ausubel et al., eds, 1994, Current Protocols in Molecular Biology, Vol. 1 , John Wiley & Sons, Inc., New York at 1 1.2.1. The binding affinity of an antibody to an antigen and the off-rate of an antibody-antigen interaction can be determined by competitive binding assays. One example of a competitive binding assay is a radioimmunoassay comprising the incubation of labeled antigen (e.g., 3 H or ,25 I) with the antibody of interest in the presence of increasing amounts of unlabeled antigen, and the detection of the antibody bound to the labeled antigen. The affinity ofthe antibody of interest for a particular antigen and the binding off-rates can be determined from the data by scatchard plot analysis. Competition with a second antibody can also be determined using radioimmunoassays. In this case, the antigen is incubated with antibody of interest is conjugated to a labeled compound (e.g., 3 H or 125 I) in the presence of increasing amounts of an unlabeled second antibody. E. Antibody Based Therapies The present invention is further directed to antibody-based therapies which involve administering antibodies of the invention to an animal, preferably a mammal, and most preferably a human patient for treating and/or preventing one or more ofthe disorders or conditions described herein. Therapeutic compounds of the invention include, but are not limited to, antibodies of the invention (including fragments, analogs and derivatives thereof as described herein) and nucleic acids encoding antibodies ofthe invention (including fragments, analogs and derivatives thereof as described herein). While not intending to be bound to theory, TRID receptors are believed to inhibit programmed cell death by a process which involves the binding of TRID ligands (e.g., TRAIL) which are then not available to bind to receptors which - I m ¬ mediate programmed cell death. Thus, agents (e.g., antibodies) which prevent binding of ligand to TRID will enhance programmed cell death. As noted above, TRID receptors have been shown to bind TRAIL. TRID receptors are also known to be present in a number of tissues and on the surfaces of a number of cell types. TRAIL is a member ofthe TNF family of cytokines which has been shown to induce apoptotic cell death in a number of tumor cell lines and appears to mediate its apoptosis inducing effects through interaction with, e.g., DR4 and DR5 receptors. These death domain containing receptors are believed to form membrane-bound self-activating signaling complexes which initiate apoptosis through cleavage of caspases. In addition, and as shown herein, TRAIL also binds to several receptors proposed to be "decoy" receptors, e.g., TRID, DcR2 (a receptor with a truncated death domain), DcRl (a GPI-anchored receptor), and OPG (a secreted protein which binds to another member of the TNF family, RANKL). Antibodies which bind to TRID receptors are useful for treating and/or preventing diseases and conditions associated with increased or decreased apoptotic cell death. Further, these antibodies vary in the effect they have on TRID receptors. These effects differ based on the specific portions ofthe TRID receptor to which the antibodies bind, the three-dimensional conformation ofthe antibody molecules themselves, and/or the manner in which they interact with the TRID receptor. Thus, antibodies which bind to the extracellular domain of a TRID receptor can either stimulate or inhibit TRID activities (e.g. , the binding of TRAIL). Antibodies which stimulate TRID receptor's ability to bind TRAIL are TRAIL binding facilitators, and antibodies which inhibit TRID receptor activities (e.g., by blocking the binding of TRAIL) are TRID antagonists. In addition. TRID has an intracellular domain which may be involved in an intracellular signaling pathway. Agonists, including antibodies, are molecules which bind TRID in a manner which stimulates the intracellular signaling pathway. Antibodies ofthe invention which function as agonists and antagonists, and TRAIL binding facilitators of TRID receptors include antigen-binding antibody fragments such as Fab and F(ab') 2 fragments, Fd, single-chain Fvs (scFv), disulfide-linked Fvs (sdFv) and fragments comprising either a V L or V H domain, as well as polyclonal, monoclonal and humanized antibodies. Each of these antigen-binding antibody fragments and antibodies are described in more detail elsewhere herein. In view ofthe above, antibodies of the invention, as well as other TRID antagonists, are useful for inhibiting TRID activity, thereby promoting apoptosis in cells which express TRID receptors (e.g. , cancer cells). Antibodies of this type are useful for prevention and/or treating diseases and conditions associated with increased cell survival and/or insensitivity to apoptosis-inducing agents (e.g., TRAIL), such as solid tissue cancers (e.g., skin cancer, head and neck tumors, breast tumors, endothelioma, lung cancer, osteoblastoma, osteoclastoma, and Kaposi's sarcoma) and leukemias. The invention encompasses anti-TRID antibodies that enhance the binding of TRAIL, denoted herein as TRAIL binding facilitators. TRAIL binding facilitators function by preventing apoptosis and are useful for preventing and/or treating diseases associated with increased apoptotic cell death. Examples of such diseases include diabetes mellitus, AIDS, neurodegenerative disorders, myelodysplastic syndromes, ischemic injury, toxin-induced liver disease, septic shock, cachexia and anorexia. When an antagonist ofthe invention is administered to an individual for the treatment and/or prevention of a disease or condition associated with increased T-cell populations or increased cell proliferation (e.g., cancer), the antagonist may be co-administered with another agent which induces apoptosis (e.g. , TRAIL) or otherwise inhibits cell proliferation (e.g., an anti-cancer drug). Combination therapies of this nature, as well as other combination therapies, are discussed below in more detail. Further, TRAIL binding facilitators of the invention (e.g., TRID antibodies which enhance the binding of TRAIL) are also useful for enhancing T-cell mediated immune responses, as well as preventing and/or treating diseases and conditions associated with decreased T-cell proliferation. Antibodies ofthe invention which enhance the binding of TRID receptor ligands to TRID receptors can inhibit T-cell apoptosis. The inhibition of apoptosis can, for example, either result in an increase in the expansion rate of in vivo T-cell populations or prevent a decrease in the size of such populations. Thus, TRAIL binding facilitators ofthe invention can be used to prevent and/or treat diseases or conditions associated with decreased or decreases in T-cell populations. Examples of such diseases and conditions include acquired immune deficiency syndrome (AIDS) and related afflictions (e.g., AIDS related complexes), T-cell immunodeficiencies, radiation sickness, and T-cell depletion due to radiation and/or chemotherapy. When a TRAIL binding facilitator ofthe invention is administered to an individual for the treatment and/or prevention of a disease or condition associated with decreased T-cell populations, the TRAIL binding facilitator may be co-administered with an agent which activates and/or induces lymphocyte proliferation (e.g., a cytokine). Combination therapies of this nature, as well as other combination therapies, are discussed below in more detail. TRID antibodies are thus useful for treating and/or preventing malignancies, abnormalities, diseases and/or conditions involving tissues and cell types which express TRID receptors. Further, malignancies, abnormalities, diseases and/or conditions which can be treated and/or prevented by the induction of programmed cell death in cells which express TRID receptors can be treated and/or prevented using TRID receptor antagonists of the invention. Similarly, malignancies, abnormalities, diseases and/or conditions which can be treated and/or prevented by inhibiting programmed cell death in cells which express TRID receptors can be treated and/or prevented using TRID receptor TRAIL binding facilitators of the invention. A number of additional malignancies, abnormalities, diseases and/or conditions which can be treated using the TRAIL binding facilitators, agonists, and antagonists ofthe invention are set out elsewhere herein, for example, in the section below entitled "Modes of Administration". The antibodies ofthe present invention may be used therapeutically in a number of ways. For example, antibodies which bind polynucleotides or polypeptides ofthe present invention can be administered to an individual (e.g., a human) either locally or systemically. Further, these antibodies can be administered alone, in combination with another therapeutic agent, or associated with or bound to a toxin. TRID antibodies may be utilized in combination with other monoclonal or chimeric antibodies, or with lymphokines, tumor necrosis factors or TNF-related molecules (e.g., TNF-α, TNF-β, TNF-γ, TNF-γ-α, TNF-γ-β, and TRAIL), or hematopoietic growth factors (e.g. , IL-2, IL-3 and IL-7). For example, antagonistic TRID antibodies may be administered in conjunction with TRAIL when one seeks to induce programmed cell death in cells which express TRID receptors ofthe invention. Combination therapies of this nature, as well as other combination therapies, are discussed below in more detail. The antibodies of the invention may be administered alone or in combination with other types of treatments (e.g. , radiation therapy, chemotherapy, hormonal therapy, immunotherapy and anti-tumor agents). Generally, administration of products of a species origin or species reactivity (in the case of antibodies) that is the same species as that ofthe patient is preferred. Thus, in a preferred embodiment, human antibodies, fragments derivatives, analogs, or nucleic acids, are administered to a human patient for therapy or prophylaxis. It is preferred to use high affinity and/or potent in vivo inhibiting and/or neutralizing antibodies against polypeptides or polynucleotides of the present invention, fragments or regions thereof, for both immunoassays directed to and therapy of disorders related to polynucleotides or polypeptides, including fragments thereof, of the present invention. Such antibodies, fragments, or regions, will preferably have an affinity for polynucleotides or polypeptides, including fragments thereof. Preferred binding affinities include those with a dissociation constant or Kd less than 5X10 "6 M, 10 "6 M, 5X10 '7 M, 10 "7 M, 5X 10 "8 M, 10- S M, 5X10- 9 M, 10- 9 M, 5X10-'°M, 10-'°M, 5X10-"M, 10-"M, 5X10- ,2 M, 10-' 2 M, 5X10 " ' 3 M, 10 "I3 M, 5X10 " ' 4 M, 10 "14 M, 5X10 " ' 5 M, and 10 " ' 5 M. Immune System-Related Disorders Diagnosis The present inventors have discovered that TRID is expressed in hematopoeitic tissues and other normal human tissues. For a number of immune system-related disorders, substantially altered (increased or decreased) levels of TRID gene expression can be detected in immune system tissue or other cells or bodily fluids (e.g., sera and plasma) taken from an individual having such a disorder, relative to a "standard" TRID gene expression level, that is, the TRID expression level in immune system tissues or bodily fluids from an individual not having the immune system disorder. Thus, the invention provides a diagnostic method useful during diagnosis of an immune system disorder, which involves measuring the expression level ofthe gene encoding the TRID protein in immune system tissue or other cells or body fluid from an individual and comparing the measured gene expression level with a standard TRID gene expression level, whereby an increase or decrease in the gene expression level compared to the standard is indicative of an immune system disorder. In particular, it is believed that certain tissues in mammals with cancer express significantly enhanced levels ofthe TRID protein and mRNA encoding the TRID when compared to a corresponding "standard" level. Further, it is believed that enhanced levels of the TRID protein can be detected in certain body fluids (e.g. , sera and plasma) from mammals with such a cancer when compared to sera from mammals ofthe same species not having the cancer. Thus, the invention provides a diagnostic method useful during diagnosis of an immune system disorder, including cancers which involves measuring the expression level ofthe gene encoding the TRID protein in immune system tissue or other cells or body fluid from an individual and comparing the measured gene expression level with a standard TRID gene expression level, whereby an increase or decrease in the gene expression level compared to the standard is indicative of an immune system disorder. Where a diagnosis of a disorder in the immune system including diagnosis of a tumor has already been made according to conventional methods, the present invention is useful as a prognostic indicator, whereby patients exhibiting altered (particularly enhanced) gene expression will experience a worse clinical outcome relative to patients expressing the gene at a level nearer the standard level. By "assaying the expression level ofthe gene encoding a TRID protein" is intended qualitatively or quantitatively measuring or estimating the level of TRID or the level ofthe mRNA encoding TRID in a first biological sample either directly (e.g. , by determining or estimating absolute protein level or mRNA level) or relatively (e.g., by comparing to the TRID protein level or mRNA level in a second biological sample). Preferably, the TRID protein level or mRNA level in the first biological sample is measured or estimated and compared to a standard TRID protein level or mRNA level, the standard being taken from a second biological sample obtained from an individual not having the disorder or being determined by averaging levels from a population of individuals not having a disorder ofthe immune system. As will be appreciated in the art, once standard TRID protein levels or mRNA levels are known, they can be used repeatedly as a standard for comparison. By "biological sample" is intended any biological sample obtained from an individual, body fluid, cell line, tissue culture, or other source which contains TRID protein or mRNA. As indicated, biological samples include body fluids (such as sera, plasma, urine, synovial fluid and spinal fluid) which contain free extracellular domain(s) (or soluable form(s)) of a TRID protein, immune system tissue, and other tissue sources found to express complete or extracellular domain of TRID. Methods for obtaining tissue biopsies and body fluids from mammals are well known in the art. Where the biological sample is to include mRNA, a tissue biopsy is the preferred source. The invention also contemplates the use of a gene ofthe present invention for diagnosing mutations in the TRID gene. For example, if a mutation is present in one ofthe genes ofthe present invention, conditions would result from a lack of production of the receptor polypeptides of the present invention. Further, mutations which enhance receptor polypeptide activity would lead to diseases associated with an over expression of the receptor polypeptide, e.g., endotoxic shock. Mutations in the genes can be detected by comparing the sequence ofthe defective gene with that of a normal one. Subsequently one can verify that a mutant gene is associated with a disease condition or the susceptibility to a disease condition. That is, a mutant gene which leads to the overexpression of TRID would be associated with an inability of TRAIL to inhibit tumor growth. Other immune system disorders which may be diagnosed by the foregoing assays include hypersensitivity, allergy, infectious disease, graft-host disease, immunodeficiency, autoimmune diseases and the like. Individuals carrying mutations in the genes ofthe present invention may be detected at the DNA level by a variety of techniques. Nucleic acids used for diagnosis may be obtained from a patient's cells, such as from blood, urine, saliva and tissue biopsy among other tissues. The genomic DNA may be used directly for detection or may be amplified enzymatically by using PCR (Saiki et al., Nature, 324:163-166 (1986)) prior to analysis. RNA or cDNA may also be used for the same puφose. As an example, PCR primers complementary to the nucleic acid ofthe instant invention can be used to identify and analyze mutations in the human genes of the present invention. For example, deletions and insertions can be detected by a change in the size of the amplified product in comparison to the normal genotype. Point mutations can be identified by hybridizing amplified DNA to radiolabeled RNA or alternatively, radiolabeled antisense DNA sequences of the present invention. Perfectly matched sequences can be distinguished from mismatched duplexes by RNase A digestion or by differences in melting temperatures. Such a diagnostic would be particularly useful for prenatal or even neonatal testing. Sequence differences between the reference gene and "mutants" may be revealed by the direct DNA sequencing method. In addition, cloned DNA segments may be used as probes to detect specific DNA segments. The sensitivity of this method is greatly enhanced when combined with PCR. For example, a sequencing primary used with double stranded PCR product or a single stranded template molecule generated by a modified PCR product The sequence determination is performed by conventional procedures with radiolabeled nucleotides or by automatic sequencing procedures with fluorescent tags Sequence changes at the specific locations may be revealed by nuclease protection assays, such as RNase and S 1 protection or the chemical cleavage method (for example, Cotton et al , PNAS, 85 4397-4401 (1985)) Assaying TRID protein levels in a biological sample can occur using antibody-based techniques For example, TRID protein expression in tissues can be studied with classical immunohistological methods (Jalkanen, M , et al , J Cell Biol 101 976-985 (1985), Jalkanen, M . etal J Cell Biol 105 3087-3096 (1987)) Other antibody-based methods useful for detecting TRID gene expression include immunoassays, such as the enzyme linked immunosorbent assay (ELISA) and the radioimmunoassay (RIA) Suitable antibody assay labels are known in the art and include enzyme labels, such as, glucose oxidase, and radioisotopes, such as iodine ( 125 I, 121 I), carbon ( l4 C), sulfur ( 35 S), tritium ( 3 H), indium (' ,2 In), and technetium ( 99m Tc), and fluorescent labels, such as fluorescein and rhodamine, and biotin In addition to assaying TRID protein levels in a biological sample obtained from an individual, TRID proteins can also be detected in vivo by imaging Antibody labels or markers for in vivo imaging of TRID proteins include those detectable by X-radiography, NMR or ESR For X-radiography, suitable labels include radioisotopes such as barium or cesium, which emit detectable radiation but are not overtly harmful to the subject Suitable markers for NMR and ESR include those with a detectable characteristic spin, such as deuterium, which may be incoφorated mto the antibody by labeling of nutrients for the relevant hybridoma A TRID-specific antibody or antibody fragment which has been labeled with an appropriate detectable imaging moiety, such as a radioisotope (for example, l31 I, " 2 In, 99m Tc), a radio-opaque substance, or a material detectable by nuclear magnetic resonance, is introduced (for example, parenterally, subcutaneously or intraperitoneally) into the mammal to be examined for immune system disorder. It will be understood in the art that the size ofthe subject and the imaging system used will determine the quantity of imaging moiety needed to produce diagnostic images. In the case of a radioisotope moiety, for a human subject, the quantity of radioactivity injected will normally range from about 5 to 20 millicuries of 99 Tc. The labeled antibody or antibody fragment will then preferentially accumulate at the location of cells which contain TRID protein. In vivo tumor imaging is described in S.W. Burchiel et al., "Immunopharmacokinetics of Radiolabeled Antibodies and Their Fragments" (Chapter 13 in Tumor Imaging: The Radiochemical Detection of Cancer, S.W. Burchiel and B. A. Rhodes, eds., Masson Publishing Inc. (1982)). Treatment The Tumor Necrosis Factor (TNF) family ligands are known to be among the most pleiotropic cytokines, inducing a large number of cellular responses, including cytotoxicity, anti-viral activity, immunoregulatory activities, and the transcriptional regulation of several genes (Goeddel, D.V. etal. , "Tumor Necrosis Factors: Gene Structure and Biological Activities," Symp. Quant. Biol. 51:591- 609 (1986), Cold Spring Harbor; Beutler, B., and Cerami, A., Annu. Rev Biochem. 57:505-518 (1988); Old, L.J., Sci. Am. 255:59-75 (1988); Fiers, W., FEBSLett. 255: 199-224 (1991)). The TNF-family ligands induce such various cellular responses by binding to TNF-family receptors. Cells which express a TRID polypeptide and are believed to have a potent cellular response to TNFR ligands include lymphocytes, endothelial cells, keratinocytes, and prostate tissue. By "a cellular response to a TNF-family ligand" is intended any genotypic, phenotypic, and/or morphologic change to a cell, cell line, tissue, tissue culture or patient that is induced by a TNF-family ligand. As indicated, such cellular responses include not only normal physiological responses to TNF-family ligands, but also diseases associated with increased apoptosis or the inhibition of apoptosis. TRID polynucleotides, polynucleotides, TRAIL binding facilitators, agonists, and/or antagonists of the invention may be administered to a patient (e.g. , mammal, preferably human) afflicted with any disease or disorder mediated (directly or indirectly) by defective, or deficient levels of, TRID. Alternatively, a gene therapy approach may be applied to treat such diseases or disorders. In one embodiment ofthe invention, TRID polynucleotide sequences are used to detect mutein TRID genes, including defective genes. Mutein genes may be identified in in vitro diagnostic assays, and by comparison ofthe TRID nucleotide sequence disclosed herein with that of a TRID gene obtained from a patient suspected of harboring a defect in this gene. Defective genes may be replaced with normal TRID -encoding genes using techniques known to one skilled in the art. In another embodiment, the TRID polypeptides, polynucleotides, TRAIL binding facilitators, agonists, and/or antagonists ofthe present invention are used as research tools for studying the phenotypic effects that result from inhibiting TRAIL/TRID interactions on various cell types. TRID polypeptides and antagonists (e.g. monoclonal antibodies to TRID) also may be used in in vitro assays for detecting TRAIL or TRID or the interactions thereof. It has been reported that certain ligands of the TNF family (of which TRAIL is a member) bind to more than one distinct cell surface receptor protein. For example, a receptor protein designated DR4 reportedly binds TRAIL, but is distinct from the TRID ofthe present invention (Pan et al, Science 276: 1 1-113, (1997); hereby incoφorated by reference). In another embodiment, a purified TRID polypeptide, TRAIL binding facilitator, agonist, and/or antagonist is used to inhibit binding of TRAIL to endogenous cell surface TRAIL receptors. By competing for TRAIL binding, soluble TRID polypeptides ofthe present invention may be employed to inhibit the interaction of TRAIL not only with cell surface TRID, but also with TRAIL receptor proteins distinct from TRID. Thus, in a further embodiment, TRID polynucleotides, polynucleotides, TRAIL binding facilitators, agonists, and/or antagonists ofthe invention are used to inhibit a functional activity of TRAIL, in in vitro or in vivo procedures. By inhibiting binding of TRAIL to cell surface receptors, TRID also inhibits biological effects that result from the binding of TRAIL to endogenous receptors. Various forms of TRID may be employed, including, for example, the above-described TRID fragments, derivatives, and variants that are capable of binding TRAIL. In a preferred embodiment, a soluble TRID, is employed to inhibit a functional activity of TRAIL, e.g. , to inhibit TRAIL-mediated apoptosis of cells susceptible to such apoptosis. Thus, in an additional embodiment, TRID is administered to a mammal (e.g., a human) to treat a TRAIL-mediated disorder. Such TRAIL-mediated disorders include conditions caused (directly or indirectly) or exacerbated by TRAIL. Diseases associated with increased cell survival, or the inhibition of apoptosis, include cancers (such as follicular lymphomas, carcinomas with p53 mutations, and hormone-dependent tumors, including, but not limited to colon cancer, cardiac tumors, pancreatic cancer, melanoma, retinoblastoma, glioblastoma, lung cancer, intestinal cancer, testicular cancer, stomach cancer, neuroblastoma, myxoma, myoma, lymphoma, endothelioma, osteoblastoma, osteoclastoma, osteosarcoma, chondrosarcoma, adenoma, breast cancer, prostate cancer, Kaposi's sarcoma and ovarian cancer); autoimmune disorders (such as multiple sclerosis, Sjogren's syndrome, Hashimoto's thyroiditis. biliary cirrhosis, Behcet's disease, Crohn's disease, polymyositis, systemic lupus erythematosus and immune-related glomerulonephritis rheumatoid arthritis) and viral infections (such as herpes viruses, pox viruses and adenoviruses), information graft v. host disease, acute graft rejection, and chronic graft rejection. In preferred embodiments, TRID polynucleotides, polypeptides, and/or antagonists of the invention are used to inhibit growth, progression, and/or metasis of cancers, in particular those listed above and in the following paragraph. Additional diseases or conditions associated with increased cell survival include, but are not limited to, progression, and/or metastases of malignancies and related disorders such as leukemia (including acute leukemias (e.g., acute lymphocytic leukemia, acute myelocytic leukemia (including myeloblastic, promyelocytic, myelomonocytic, monocytic, and erythroleukemia)) and chronic leukemias (e.g., chronic myelocytic (granulocytic) leukemia and chronic lymphocytic leukemia)), polycythemia vera, lymphomas (e.g. , Hodgkin's disease and non-Hodgkin's disease), multiple myeloma, Waldenstrom's macroglobulinemia, heavy chain disease, and solid tumors including, but not limited to, sarcomas and carcinomas such as fibrosarcoma, myxosarcoma, liposarcoma, chondrosarcoma, osteogenic sarcoma, chordoma, angiosarcoma, endothehosarcoma, lymphangiosarcoma, lymphangioendotheliosarcoma, synovioma, mesothelioma, Ewing's tumor, leiomyosarcoma, rhabdomyosarcoma, colon carcinoma, pancreatic cancer, breast cancer, ovarian cancer, prostate cancer, squamous cell carcinoma, basal cell carcinoma, adenocarcinoma, sweat gland carcinoma, sebaceous gland carcinoma, papillary carcinoma, papillary adenocarcinomas, cystadenocarcinoma, medullary carcinoma, bronchogenic carcinoma, renal cell carcinoma, hepatoma, bile duct carcinoma, choriocarcinoma, seminoma, embryonal carcinoma, Wilm's tumor, cervical cancer, testicular tumor, lung carcinoma, small cell lung carcinoma, bladder carcinoma, epithelial carcinoma, glioma, astrocytoma, medulloblastoma, craniopharyngioma, ependymoma, pinealoma, hemangioblastoma, acoustic neuroma, oligodendroglioma, menangioma, melanoma, neuroblastoma, and retinoblastoma. Diseases associated with increased apoptosis include AIDS; neurodegenerative disorders (such as Alzheimer's disease, Parkinson's disease, Amyotrophic lateral sclerosis, Retinitis pigmentosa, Cerebellar degeneration and brain tumor or prior associated disease); autoimmune disorders (such as, multiple sclerosis, Sjogren's syndrome, Hashimoto's thyroiditis, biliary cirrhosis, Behcet's disease, Crohn's disease, polymyositis, systemic lupus erythematosus and immune- related glomerulonephritis and rheumatoid arthritis), myelodysplastic syndromes (such as aplastic anemia), graft v. host disease, ischemic injury (such as that caused by myocardial infarction, stroke and reperfusion injury), liver injury (such as hepatitis related liver injury, ischemia reperfusion injury, cholestosis (bile duct injury) and liver cancer), toxin-induced liver disease (such as that caused by alcohol), septic shock, cachexia and anorexia. In preferred embodiments, TRID polynucleotides, polypeptides TRAIL binding facilitators, and/or agonists are used to treat the diseases and disorders listed above. Many ofthe pathologies associated with HIV are mediated by apoptosis, including HIV-induced nephropathy and HIV encephalitis. Thus, in additional preferred embodiments, TRID polynucleotides, polypeptides, TRAIL binding facilitators, and/or TRID agonists of the invention are used to treat AIDS and pathologies associated with AIDS. Another embodiment of the present invention is directed to the use of TRID to reduce TRAIL-mediated death of T cells in HIV-infected patients. The role of T cell apoptosis in the development of AIDS has been the subject of a number of studies (see. for example, Meyaard et al, Science 257:217-219, 1992; Groux et al, J Exp. Med., 775:331, 1992; and Oyaizu et al, in Cell Activation and Apoptosis in HIV Infection, Andrieu and Lu, Eds., Plenum Press, New York, 1995, pp. 101-1 14). Fas-mediated apoptosis has been implicated in the loss of T cells in HIV individuals (Katsikis et al, J. Exp. Med. 757:2029-2036, 1995). The state of immunodeficiency that defines AIDS is secondary to a decrease in the number and function of CD4 " T-lymphocytes. Recent reports estimate the daily loss of CD4 + T cells to be between 3.5 X 10 7 and 2 X 10 9 cells (Wei X., et al, Nature 575: 1 17-122 (1995)). One cause of CD4 + T cell depletion in the setting of HIV infection is believed to be HIV-induced apoptosis. Indeed, HIV-induced apoptotic cell death has been demonstrated not only in vitro but also, more importantly, in infected individuals (Ameisen, J.C., AIDS 5: 1 197-1213 (1994) ; Finkel, T.H., and Banda, N.K., Curr. Opin. Immunol. (5:605-615(1995); Muro- Cacho, CA. et al, J. Immunol 154:5555-5566 (1995)). Furthermore, apoptosis and CD4 + T-lymphocyte depletion is tightly correlated in different animal models of AIDS (Brunner, T., et al, Nature 575:441-444 (1995); Gougeon, M.L., et al, AIDS Res. Hum. Retroviruses 9:553-563 (1993)) and, apoptosis is not observed in those animal models in which viral replication does not result in AIDS (Gougeon, M.L. et al., AIDS Res. Hum. Retroviruses 9:553-563 (1993)). Further data indicates that uninfected but primed or activated T lymphocytes from HIV- infected individuals undergo apoptosis after encountering the TNF-family ligand FasL. Using monocytic cell lines that result in death following HIV infection, it has been demonstrated that infection of U937 cells with HIV results in the de novo expression of FasL and that FasL mediates HIV-induced apoptosis (Badley, A.D. etal, J. Virol. 70: 199-206 (1996)). Further the TNF-family ligand was detectable in uninfected macrophages and its expression was upregulated following HIV infection resulting in selective killing of uninfected CD4 T-lymphocytes (Badley, A.O et al, J. Virol 70: 199-206 (1996)). It is also possible that T cell apoptosis occurs through multiple mechanisms. Thus, by the invention, a method for treating HIV * individuals is provided which involves administering soluble TRID (e.g. , the extracellular domain) and/or TRID agonists of the present invention to reduce selective killing of CD4 * T- lymphocytes. Modes of administration and dosages are discussed in detail below. While not wanting to be bound by theory, activated human T-cells are believed to be induced to undergo programmed cell death (apoptosis) upon triggering through the CD3/T-cell receptor complex, a process termed activated-induced cell death (AICD). AICD of CD4 * T-cells isolated from HIV-infected asymptomatic individuals has been reported (Groux et al, supra). Thus. AICD may play a role in the depletion of CD4 + T-cells and the progression to AIDS in HIV-infected individuals. Thus, the present invention provides a method of inhibiting TRAIL-mediated T-cell death in HIV patients, comprising administering a TRID polypeptide of the invention (preferably, a soluble TRID polypeptide) and/or TRID agonist of the invention to the patients. Modes of administration and dosages are discussed in detail below. In one embodiment, the patient is asymptomatic when treatment with TRID commences. If desired, prior to treatment, peripheral blood T-cells may be extracted from an HIV patient, and tested for susceptibility to TRAIL-mediated cell death by procedures known in the art. In one embodiment, a patient's blood or plasma is contacted with TRID polypeptides ofthe invention ex vivo. The TRID polypeptides of the invention may be bound to a suitable chromatography matrix by procedures known in the art. The patient's blood or plasma flows through a chromatography column containing TRID bound to the matrix, before being returned to the patient. The immobilized TRID polypeptide binds TRAIL, thus removing TRAIL protein from the patient's blood. In additional embodiments a TRID polypeptide and/or agonist of the invention is administered in combination with other inhibitors of T-cell apoptosis. For example, as discussed above, Fas-mediated apoptosis also has been implicated in loss of T-cells in HIV individuals (Katsikis et al, J. Exp. Med. 181 :2029-2036, 1995). Thus, a patient susceptible to both Fas ligand mediated and TRAIL mediated T-cell death may be treated with both an agent that blocks TRAIL/TRAIL receptor interactions and an agent that blocks Fas-ligand/Fas interactions. Suitable agents for blocking binding of Fas-ligandto Fas include, but are not limited to, soluble Fas polypeptides; multimeric forms of soluble Fas polypeptides (e.g.. dimers of sFas/Fc); anti-Fas antibodies that bind Fas without transducing the biological signal that results in apoptosis; anti-Fas-ligand antibodies that block binding of Fas-ligand to Fas; and muteins of Fas-ligand that bind Fas but do not transduce the biological signal that results in apoptosis. Preferably, the antibodies employed according to this method are monoclonal antibodies. Examples of suitable agents for blocking Fas-ligand/Fas interactions, including blocking anti-Fas monoclonal antibodies, are described in International application publication number WO 95/10540. hereby incoφorated by reference. TRID polypeptides or polynucleotides encoding TRID of the invention may be used to treat cardiovascular disorders, including peripheral artery disease, such as limb ischemia. Cardiovascular disorders include cardiovascular abnormalities, such as arterio-arterial fistula, arteriovenous fistula, cerebral arteriovenous malformations, congenital heart defects, pulmonary atresia, and Scimitar Syndrome. Congenital heart defects include aortic coarctation, cor triatriatum, coronary vessel anomalies, crisscross heart, dextrocardia, patent ductus arteriosus, Ebstein's anomaly, Eisenmenger complex, hypoplastic left heart syndrome, levocardia, tetralogy of fallot, transposition of great vessels, double outlet right ventricle, tricuspid atresia, persistent truncus arteriosus, and heart septal defects, such as aortopulmonary septal defect, endocardial cushion defects, Lutembacher's Syndrome, trilogy of Fallot, thrombotic microangiopathies (e.g. , thrombotic thrombocytopenic puφura (TTP) and hemolytic-uremic syndrome (HUS ). and ventricular heart septal defects. Cardiovascular disorders also include heart disease, such as arrhythmias, carcinoid heart disease, high cardiac output, low cardiac output, cardiac tamponade, endocarditis (including bacterial), heart aneurysm, cardiac arrest, congestive heart failure, congestive cardiomyopathy, paroxysmal dyspnea, cardiac edema, heart hypertrophy, congestive cardiomyopathy, left ventricular hypertrophy, right ventricular hypertrophy, post-infarction heart rupture, ventricular septal rupture, heart valve diseases, myocardial diseases, myocardial ischemia, pericardial effusion, pericarditis (including constrictive and tuberculous), pneumopericardium, postpericardiotomy syndrome, pulmonary heart disease, rheumatic heart disease, ventricular dysfunction, hyperemia, cardiovascular pregnancy complications, Scimitar Syndrome, cardiovascular syphilis, and cardiovascular tuberculosis. Arrhythmias include sinus arrhythmia, atrial fibrillation, atrial flutter, bradycardia, extrasystole, Adams-Stokes Syndrome, bundle-branch block, sinoatrial block, long QT syndrome, parasystole, Lown-Ganong-Levine Syndrome, Mahaim-type pre-excitation syndrome, Wolff-Parkinson-White syndrome, sick sinus syndrome, tachycardias, and ventricular fibrillation. Tachycardias include paroxysmal tachycardia, supraventricular tachycardia, accelerated idioventricular rhythm, atrioventricular nodal reentry tachycardia, ectopic atrial tachycardia, ectopic junctional tachycardia, sinoatrial nodal reentry tachycardia, sinus tachycardia, Torsades de Pointes, and ventricular tachycardia. Heart valve disease include aortic valve insufficiency, aortic valve stenosis, hear murmurs, aortic valve prolapse, mitral valve prolapse, tricuspid valve prolapse, mitral valve insufficiency, mitral valve stenosis, pulmonary atresia, pulmonary valve insufficiency, pulmonary valve stenosis, tricuspid atresia, tricuspid valve insufficiency, and tricuspid valve stenosis. Myocardial diseases include alcoholic cardiomyopathy, congestive cardiomyopathy, hypertrophic cardiomyopathy, aortic subvalvular stenosis, pulmonary subvalvular stenosis, restrictive cardiomyopathy, Chagas cardiomyopathy, endocardial fibroelastosis, endomyocardial fibrosis, Kearns Syndrome, myocardial reperfusion injury, and myocarditis. Myocardial ischemias include coronary disease, such as angina pectoris, coronary aneurysm, coronary arteriosclerosis, coronary thrombosis, coronary vasospasm, myocardial infarction and myocardial stunning. Cardiovascular diseases also include vascular diseases such as aneurysms, angiodysplasia, angiomatosis, bacillary angiomatosis, Hippel-Lindau Disease, Klippel-Trenaunay- Weber Syndrome, Sturge-Weber Syndrome, angioneurotic edema, aortic diseases, Takayasu's Arteritis, aortitis, Leriche's Syndrome, arterial occlusive diseases, arteritis, enarteritis, polyarteritis nodosa, cerebrovascular disorders, diabetic angiopathies, diabetic retinopathy, embolisms, thrombosis, erythromelalgia, hemorrhoids, hepatic veno-occlusive disease, hypertension, hypotension, ischemia, peripheral vascular diseases, phlebitis, pulmonary veno- occlusive disease, Raynaud's disease, CREST syndrome, retinal vein occlusion, Scimitar syndrome, superior vena cava syndrome, telangiectasia, atacia telangiectasia, hereditary hemorrhagic telangiectasia, varicocele, varicose veins, varicose ulcer, vasculitis, and venous insufficiency. Aneurysms include dissecting aneurysms, false aneurysms, infected aneurysms, ruptured aneurysms, aortic aneurysms, cerebral aneurysms, coronary aneurysms, heart aneurysms, and iliac aneurysms. Arterial occlusive diseases include arteriosclerosis, intermittent claudication, carotid stenosis, fibromuscular dysplasias, mesenteric vascular occlusion, Moyamoya disease, renal artery obstruction, retinal artery occlusion, and thromboangiitis obliterans. Cerebrovascular disorders include carotid artery diseases, cerebral amyloid angiopathy, cerebral aneurysm, cerebral anoxia, cerebral arteriosclerosis, cerebral arteriovenous malformation, cerebral artery diseases, cerebral embolism and thrombosis, carotid artery thrombosis, sinus thrombosis, Wallenberg's syndrome, cerebral hemorrhage, epidural hematoma, subdural hematoma, subaraxhnoid hemorrhage, cerebral infarction, cerebral ischemia (including transient), subclavian steal syndrome, periventricular leukomalacia, vascular headache, cluster headache, migraine, and vertebrobasilar insufficiency. Embolisms include air embolisms, amniotic fluid embolisms, cholesterol embolisms, blue toe syndrome, fat embolisms, pulmonary embolisms, and thromoboembolisms. Thrombosis include coronary thrombosis, hepatic vein thrombosis, retinal vein occlusion, carotid artery thrombosis, sinus thrombosis, Wallenberg's syndrome, and thrombophlebitis. Ischemia includes cerebral ischemia, ischemic colitis, compartment syndromes, anterior compartment syndrome, myocardial ischemia, reperfusion injuries, and peripheral limb ischemia. Vasculitis includes aortitis, arteritis, Behcet's Syndrome, Churg-Strauss Syndrome, mucocutaneous lymph node syndrome, thromboangiitis obliterans, hypersensitivity vasculitis, Schoenlein- Henoch puφura, allergic cutaneous vasculitis, and Wegener's granulomatosis. In one embodiment, TRID polynucleotides, polypeptides, TRAIL binding facilitators, and/or agonists of the invention are used to treat and/or prevent thrombotic microangiopathies. One such disorder is thrombotic thrombocytopenic puφura (TTP) (Kwaan, H.C., Semin. Hematol 24:11 (1987); Thompson et al, Blood 50:1890 (1992)). Increasing TTP-associated mortality rates have been reported by the U.S. Centers for Disease Control (Torok et al, Am. J. Hematol. 50:84 (1995)). Plasma from patients afflicted with TTP (including HIV+ and HIV- patients) induces apoptosis of human endothelial cells of dermal microvascular origin, but not large vessel origin (Laurence et al, Blood 87:3245 (1996)). Plasma of TTP patients thus is thought to contain one or more factors that directly or indirectly induce apoptosis. As described in International patent application number WO 97/01633 (hereby incoφorated by reference), TRAIL is present in the serum of TTP patients, and is likely to play a role in inducing apoptosis of microvascular endothelial cells. Another thrombotic microangiopathy is hemolytic-uremic syndrome (HUS) (Moake, J.L., Lancet, 343:393 (1994); Melnyk et al, (Arch. Intern. Med., 155:2011 (1995); Thompson et al, supra). Thus, in one embodiment, the invention is directed to use of TRID to treat and/or prevent the condition that is often referred to as "adult HUS" (even though it can strike children as well). A disorder known as childhood/diarrhea-associated HUS differs in etiology from adult HUS. In another embodiment, conditions characterized by clotting of small blood vessels may be treated and/or prevented using TRID Such conditions include, but are not limited to, those described herein. For example, cardiac problems seen in about 5-10% of pediatric AIDS patients are believed to involve clotting of small blood vessels. Breakdown ofthe microvasculature in the heart has been reported in multiple sclerosis patients. As a further example, treatment and/or prevention of systemic lupus erythematosus (SLE) is contemplated. In one embodiment, a patient's blood or plasma is contacted TRID polynucleotides and/or polypeptides of the invention may be bound to a suitable chromatography matrix by procedures known in the art. According to this embodiment, the patient's blood or plasma flows through a chromatography column containing TRID polynucleotides and/or polypeptides of the invention bound to the matrix, before being returned to the patient. The immobilized TRID binds TRAIL, thus removing TRAIL protein from the patient's blood. Alternatively, TRID polynucleotides and/or polypeptides ofthe invention may be administered in vivo to a patient afflicted with a thrombotic microangiopathy. In one embodiment, a soluble form of TRID polypeptide ofthe invention is administered to the patient. Thus, the present invention provides a method for treating and/or preventing a thrombotic microangiopathy, involving use of an effective amount of TRID. A TRID polypeptide may be employed in in vivo or ex vivo procedures, to inhibit TRAIL-mediated damage to (e.g. , apoptosis of) microvascular endothelial cells. TRID polynucleotides and/or polypeptides of the invention may be employed in combination with other agents useful in treating and/or preventing a particular disorder. For example, in an in vitro study reported by Laurence et al. (Blood 57:3245 (1996)), some reduction of TTP plasma-mediated apoptosis of microvascular endothelial cells was achieved by using an anti-Fas blocking antibody, aurintricarboxylic acid, or normal plasma depleted of cryoprecipitate. Thus, a patient may be treated with a polynucleotide and/or polypeptide of the invention in combination with an agent that inhibits Fas-ligand-mediated apoptosis of endothelial cells, such as, for example, an agent described above. In one embodiment, TRID polynucleotides and/or polypeptides ofthe invention and an anti-FAS blocking antibody are both administered to a patient afflicted with a disorder characterized by thrombotic microangiopathy, such as TTP or HUS. Examples of blocking monoclonal antibodies directed against Fas antigen (CD95) are described in International patent application publication number WO 95/10540, hereby incoφorated by reference. The naturally occurring balance between endogenous stimulators and inhibitors of angiogenesis is one in which inhibitory influences predominate. Rastinejad et al, Cell 5(5:345-355 (1989). In those rare instances in which neovascularization occurs under normal physiological conditions, such as wound healing, organ regeneration, embryonic development, and female reproductive processes, angiogenesis is stringently regulated and spatially and temporally delimited. Under conditions of pathological angiogenesis such as that characterizing solid tumor growth, these regulatory controls fail. Unregulated angiogenesis becomes pathologic and sustains progression of many neoplastic and non-neoplastic diseases. A number of serious diseases are dominated by abnormal neovascularization including solid tumor growth and metastases, arthritis, some types of eye disorders, and psoriasis. See, e.g. , reviews by Moses et al, Biotech. 9:630-634 (1991); Folkman et al, N. Engl J. Med, 555:1757-1763 (1995); Auerbach et al, J. Microvasc. Res. 29:401-41 1 (1985); Folkman, Advances in Cancer Research, eds. Klein and Weinhouse, Academic Press, New York, pp. 175-203 (1985); Patz, Am. J. Opthalmol 94:715-743 (1982); and Folkman etal, Science 221 :719-725 (1983). In a number of pathological conditions, the process of angiogenesis contributes to the disease state. For example, significant data have accumulated which suggest that the growth of solid tumors is dependent on angiogenesis. Folkman and Klagsbrun, Science 255:442-447 (1987). The present invention provides for treatment of diseases or disorders associated with neovascularization by administration ofthe TRID polynucleotides and/or polypeptides ofthe invention (including TRID agonists and/or antagonists). Malignant and metastatic conditions which can be treated with the polynucleotides and polypeptides of the invention include, but are not limited to those malignancies, solid tumors, and cancers described herein and otherwise known in the art (for a review of such disorders, see Fishman et al., Medicine, 2d Ed., J. B. Lippincott Co., Philadelphia (1985)). Additionally, ocular disorders associated with neovascularization which can be treated with the TRID polynucleotides and polypeptides of the present invention (including TRID agonists and TRID antagonists) include, but are not limited to: neovascular glaucoma, diabetic retinopathy, retinoblastoma, retrolental fibroplasia, uveitis, retinopathy of prematurity macular degeneration, corneal graft neovascularization, as well as other eye inflammatory diseases, ocular tumors and diseases associated with choroidal or iris neovascularization. See, e.g. , reviews by Waltman et al, Am. J. Ophthal 55:704-710 (1978) and Gartner et al, Surv. Ophthal 22:291-312 (1978). Additionally, disorders which can be treated with the TRID polynucleotides and polypeptides of the present invention (including TRID agonists and TRID antagonists) include, but are not limited to, hemangioma, arthritis, psoriasis, angiofibroma, atherosclerotic plaques, delayed wound healing, granulations, hemophilic joints, hypertrophic scars, nonunion fractures, Osler- Weber syndrome, pyogenic granuloma, scleroderma, trachoma, and vascular adhesions. In rejection of an allograft, the immune system ofthe recipient animal has not previously been primed to respond because the immune system for the most part is only primed by environmental antigens. Tissues from other members ofthe same species have not been presented in the same way that, for example, viruses and bacteria have been presented. In the case of allograft rejection, immunosuppressive regimens are designed to prevent the immune system from reaching the effector stage. However, the immune profile of xenograft rejection may resemble disease recurrence more than allograft rejection. In the case of disease recurrence, the immune system has already been activated, as evidenced by destruction of the native islet cells. Therefore, in disease recurrence the immune system is already at the effector stage. Antagonist of the present invention are able to suppress the immune response to both allografts and xenografts because lymphocytes activated and differentiated into effector cells will express TRID polypeptides, and thereby are susceptible to compounds which enhance TRID activity. Thus, the present invention further provides a method for creating immune privileged tissues. TRID antagonists or agonists ofthe invention may be useful for treating and/or preventing inflammatory diseases, such as rheumatoid arthritis, osteoarthritis, psoriasis, septicemia, and inflammatory bowel disease. Polynucleotides and/or polypeptides of the invention and/or agonists and/or antagonists thereof are useful in the diagnosis and treatment or prevention of a wide range of diseases and/or conditions. Such diseases and conditions include, but are not limited to, cancer (e.g., immune cell related cancers, breast cancer, prostate cancer, ovarian cancer, follicular lymphoma, cancer associated with mutation or alteration of p53, brain tumor, bladder cancer, uterocervical cancer, colon cancer, colorectal cancer, non-small cell carcinoma ofthe lung, small cell carcinoma of the lung, stomach cancer, etc.), lymphoproliferative disorders (e.g., lymphadenopathy), microbial (e.g., viral, bacterial, etc.) infection (e.g., HIV-1 infection, HIV-2 infection, heφesvirus infection (including, but not limited to, HSV-1, HSV-2, CMV, VZV, HHV-6, HHV-7, EBV), adenovirus infection, poxvirus infection, human papilloma virus infection, hepatitis infection (e.g. , HAV, HBV, HCV, etc.), Helicobacter pylori infection, invasive Staphylococcia, etc.), parasitic infection, nephritis, bone disease (e.g., osteoporosis), atherosclerosis, pain, cardiovascular disorders (e.g. , neovascularization, hypovascularization or reduced circulation (e.g., ischemic disease (e.g., myocardial infarction, stroke, etc.))). AIDS, allergy, inflammation, neurodegenerative disease (e.g. , Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, pigmentary retinitis, cerebellar degeneration, etc.), graft rejection (acute and chronic), graft vs. host disease, diseases due to osteomyelodysplasia (e.g., aplastic anemia, etc.), joint tissue destruction in rheumatism, liver disease (e.g., acute and chronic hepatitis, liver injury, and cirrhosis), autoimmune disease (e.g., multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, immune complex glomerulonephritis, autoimmune diabetes, autoimmune thrombocytopemc puφura, Grave's disease, Hashimoto's thyroiditis. etc.), cardiomyopathy (e.g., dilated cardiomyopathy), diabetes, diabetic complications (e.g., diabetic nephropathy, diabetic neuropathy, diabetic retinopathy), influenza, asthma, psoriasis, glomerulonephritis, septic shock, and ulcerative colitis. Polynucleotides and/or polypeptides of the invention and/or agonists and/or antagonists thereof are useful in promoting angiogenesis, and wound healing (e.g., wounds, burns, and bone fractures), and regulating hematopoiesis. Polynucleotides and/or polypeptides of the invention and/or agonists and/or antagonists thereof are also useful as an adjuvant to enhance immune responsiveness to specific antigen, anti-viral immune responses,. More generally, polynucleotides and/or polypeptides of the invention and/or agonists and/or antagonists thereof are useful in regulating (i.e., elevating or reducing) immune response. For example, polynucleotides and/or polypeptides ofthe invention may be useful in preparation or recovery from surgery, trauma, radiation therapy, chemotherapy, and transplantation, or may be used to boost immune response and/or recovery in the elderly and immunocompromised individuals. Alternatively, polynucleotides and/or polypeptides ofthe invention and/or agonists and/or antagonists thereof are useful as immunosuppressive agents, for example in the treatment or prevention of autoimmune disorders. In specific embodiments, polynucleotides and/or polypeptides ofthe invention are used to treat or prevent chronic inflammatory, allergic or autoimmune conditions, such as those described herein or are otherwise known in the art. Thus, in one aspect, the present invention is directed to a method for enhancing apoptosis induced by a TNF-family ligand, which involves administering to a cell which expresses a TNFR polypeptide an effective amount of an antagonist of the TRID polypeptide, capable of inhibiting TRID expression or its ligand binding ability (e.g. , to TRAIL). Preferably, TNFR mediated signaling is increased to treat a disease wherein decreased apoptosis is exhibited. Antagonist can include monoclonal antibodies directed against the TRID polypeptide. By "antagonist" is intended naturally occurring and synthetic compounds capable of enhancing or potentiating apoptosis. By "agonist" is intended naturally occurring and synthetic compounds capable of inhibiting apoptosis. Whether any candidate "antagonist" or "agonist" ofthe present invention can enhance or inhibit apoptosis can be determined using art-known TNF-family ligand/receptor cellular response assays, including those described in more detail below. One such screening procedure involves the use of melanophores which are transfected to co-express a TNFR receptor which binds a TRAIL such as DR4 or DR5, described elsewhere herein, and the TRID receptor ofthe present invention. Such a screening technique is described in PCT WO 92/01810, published February 6, 1992. Such an assay may be employed, for example, for screening for a compound which inhibits (or enhances) the activity ofthe receptor polypeptide of the present invention by contacting the melanophore cells which encode the receptors with both a TNF-family ligand and the candidate antagonist (or agonist). Inhibition or enhancement ofthe signal generated by the ligand indicates that the compound is an antagonist or agonist of TRID activity. The TRID polypeptide and its agonists inhibit activation of the TNFR receptor, e.g., TRAIL receptor, whereas antagonists will increase activation. Other screening techniques include the use of cells which express a TRAIL receptor and TRID (for example, transfected CHO cells) in a system which measures extracellular pH changes caused by receptor activation, for example, as described in Science 246: 181 -296 (October 1989). For example, compounds may be contacted with a cell which expresses a TRAIL receptor polypeptide and TRID ofthe present invention and a second messenger response, e.g. , signal transduction or pH changes, may be measured to determine whether the potential compound activates or inhibits the TRAIL receptor. Another such screening technique involves introducing RNA encoding the receptors into Xenopus oocytes to transiently express TRID and a TRAIL receptor. The receptor oocytes may then be contacted with the receptor ligand and a compound to be screened, followed by detection of inhibition or activation of a calcium signal in the case of screening for compounds which are thought to inhibit activation ofthe receptor. Another screening technique involves expressing in cells a construct wherein the TRAIL receptor is linked to a phospholipase C or D. Such cells include endothelial cells, smooth muscle cells, embryonic kidney cells, etc. The screening may be accomplished as hereinabove described by detecting activation ofthe receptor or inhibition of activation ofthe receptor from the phospholipase signal in the presence of TRID either co-expressed or added in soluble form along with the candidate compound. Another method involves screening for compounds which inhibit activation of a TRAIL receptor polypeptide in the presence ofthe TRID polypeptide ofthe present invention, either co-expressed or in soluble form. Agonists ofthe present invention are identified by determining inhibition of binding of labeled ligand to cells which have the TRAIL receptor on the surface thereof. Such a method involves transfecting a eukaryotic cell with DNA encoding a TRAIL binding receptor such that the cell expresses the receptor on its surface and contacting the cell with a compound in the presence of a labelled TRAIL and TRID. TRAIL can be labeled, e.g., by radioactivity. The amount of labeled TRAIL bound to the receptors is measured, e.g., by measuring radioactivity of the receptors. If the compound binds to the TRID receptor as determined by an increase of labeled TRAIL which binds to the TRAIL receptor, the compound is a TRID antagonist. Further screening assays for agonist and antagonist ofthe present invention are described in Tartaglia, L.A., and Goeddel, D.V., J. Biol. Chem. 267(7):4304- 4307(1992). Thus, in a further aspect, a screening method is provided for determining whether a candidate TRID antagonist or agonist is capable of enhancing or inhibiting a cellular response to a TNF-family ligand (e.g. , apoptosis induced by TRAIL). The method involves contacting cells which express a TNFR polypeptide with a candidate compound, TRID, and a TNF-family ligand, assaying a cellular response, and comparing the cellular response to a standard cellular response, the standard being assayed when contact is made with the ligand in the presence of TRID but in absence ofthe candidate compound, whereby an increased cellular response over the standard indicates that the candidate compound is an antagonist and a decreased cellular response compared to the standard indicates that the candidate compound is an agonist. By "assaying a cellular response" is intended qualitatively or quantitatively measuring a cellular response to a candidate compound and/or a TNF-family ligand (e.g. , determining or estimating an increase or decrease in T cell proliferation or tritiated thymidine labeling). By the invention, a cell expressing the TNFR polypeptide can be contacted with either an endogenous or exogenously administered TNF-family ligand. Antagonist according to the present invention include naturally occurring and synthetic compounds such as, for example, TNF family ligand peptide fragments, transforming growth factor, neurotransmitters (such as glutamate, dopamine, N-methyl-D-aspartate), tumor suppressors (p53), cytolytic T cells and antimetabolites. Preferred agonist include chemotherapeutic drugs such as, for example, cisplatin, doxorubicin, bleomycin, cytosine arabinoside, nitrogen mustard, methotrexate and vincristine. Others include ethanol and -amyloid peptide. (Science 2(57:1457-1458 (1995)). Further preferred antagonist includes polyclonal and monoclonal antibodies raised against the TRID polypeptide, or a fragment thereof. Agonists according to the present invention include naturally occurring and synthetic compounds such as, for example, the CD40 ligand, neutral amino acids, zinc, estrogen, androgens, viral genes. (such as Adenovirus EIB, Baculovirus p35 and IAP, Cowpox virus crmA , Epstein-Barr virus BHRF1, LMP-1, African swine fever virus LMW5-HL, and Heφesvirus yl 34.5), calpain inhibitors, cysteine protease inhibitors, and tumor promoters (such as PMA, Phenobarbital, and - Hexachlorocyclohexane). Other Agonists include polyclonal and monoclonal antagonist antibodies raised against TRAIL polypeptides or a fragment thereof. Other potential antagonists include antisense molecules. In specific embodiments, antagonists according to the present invention are nucleic acids corresponding to the sequences contained in TRID, or the complementary strand thereof, and/or to nucleotide sequences contained in ATCC Deposit No. 97798. In one embodiment, antisense sequence is generated internally by the organism, in another embodiment, the antisense sequence is separately administered (see, for example, Okano H. et al, J. Neurochem. 56:560 (1991), and Oligodeoxynucleotides as Antisense Inhibitors of Gene Expression, CRC Press, Boca Raton, FL (1988). Antisense technology can be used to control gene expression through antisense DNA or RNA or through triple-helix formation. Antisense techniques are discussed, for example, in Okano, J. Neurochem. 56:560 (1991); Oligodeoxynucleotides as Antisense Inhibitors of Gene Expression, CRC Press, Boca Raton, FL (1988). Triple helix formation is discussed in, for instance Lee etal, Nucleic Acids Research 6:3013 (1979); Cooney etal, Science 247:456 (1988); and Dervan et al, Science 257: 1360 (1991). The methods are based on binding of a polynucleotide to a complementary DNA or RNA. For example, the 5' coding portion of a polynucleotide that encodes the mature polypeptide of the present invention may be used to design an antisense RNA oligonucleotide of from about 10 to 40 base pairs in length. A DNA oligonucleotide is designed to be complementary to a region ofthe gene involved in transcription thereby preventing transcription and the production of the receptor. The antisense RNA oligonucleotide hybridizes to the mRNA in vivo and blocks translation of the mRNA molecule into receptor polypeptide. The oligonucleotides described above can also be delivered to cells such that the antisense RNA or DNA may be expressed in vivo to inhibit production of the receptor. In one embodiment, the TRID antisense nucleic acid ofthe invention is produced intracellularly by transcription from an exogenous sequence. For example, a vector or a portion thereof, is transcribed, producing an antisense nucleic acid (RNA) of the invention. Such a vector would contain a sequence encoding the TRID antisense nucleic acid. Such a vector can remain episomal or become chromosomally integrated, as long as it can be transcribed to produce the desired antisense RNA. Such vectors can be constructed by recombinant DNA technology methods standard in the art. Vectors can be plasmid, viral, or others know in the art, used for replication and expression in vertebrate cells. Expression ofthe sequence encoding TRID, or fragments thereof, can be by any promoter known in the art to act in vertebrate, preferably human cells. Such promoters can be inducible or constitutive. Such promoters include, but are not limited to, the S V40 early promoter region (Bernoist and Chambon, Nature 29:304-310 (1981), the promoter contained in the 3' long terminal repeat of Rous sarcoma virus (Yamamoto et al, Cell 22:181-191 (1980), the heφes thymidine promoter (Wagner et al. , Proc. Natl Acad. Sci. U. S.A. 75: 1441 - 1445 (1981), the regulatory sequences ofthe metallothionein gene (Brinster, etal, Nature 296:39-42 (1982)), etc. The antisense nucleic acids of the invention comprise, or alternatively consist of, a sequence complementary to at least a portion of an RNA transcript of a TRID gene. However, absolute complementarity, although preferred, is not required. A sequence "complementary to at least a portion of an RNA," referred to herein, means a sequence having sufficient complementarity to be able to hybridize with the RNA, forming a stable duplex; in the case of double stranded TRID antisense nucleic acids, a single strand of the duplex DNA may thus be tested, or triplex formation may be assayed. The ability to hybridize will depend on both the degree of complementarity and the length ofthe antisense nucleic acid Generally, the larger the hybridizing nucleic acid, the more base mismatches with a TRID RNA it may contain and still form a stable duplex (or triplex as the case may be). One skilled in the art can ascertain a tolerable degree of mismatch by use of standard procedures to determine the melting point ofthe hybridized complex. Oligonucleotides that are complementary to the 5' end ofthe message, e.g. , the 5' untranslated sequence up to and including the AUG initiation codon, should work most efficiently at inhibiting translation. However, sequences complementary to the 3' untranslated sequences of mRNAs have been shown to be effective at inhibiting translation of mRNAs as well. See generally, Wagner. R., Nature 372:333-335 (1994). Thus, oligonucleotides complementary to either the 5'- or 3'- non- translated, non-coding regions ofthe TRID shown in SEQ ID NO: 1 could be used in an antisense approach to inhibit translation of endogenous TRID mRNA. Oligonucleotides complementary to the 5' untranslated region of the mRNA should include the complement of the AUG start codon. Antisense oligonucleotides complementary to mRNA coding regions are less efficient inhibitors of translation but could be used in accordance with the invention. Whether designed to hybridize to the 5'-, 3'- or coding region of TRID mRNA, antisense nucleic acids should be at least six nucleotides in length, and are preferably oligonucleotides ranging from 6 to about 50 nucleotides in length. In specific aspects the oligonucleotide is at least 10 nucleotides, at least 17 nucleotides, at least 25 nucleotides or at least 50 nucleotides. The polynucleotides of the invention can be DNA or RNA or chimeric mixtures or derivatives or modified versions thereof, single-stranded or double- stranded. The oligonucleotide can be modified at the base moiety, sugar moiety. or phosphate backbone, for example, to improve stability of the molecule, hybridization, etc. The oligonucleotide may include other appended groups such as peptides (e.g., for targeting host cell receptors in vivo), or agents facilitating transport across the cell membrane (see, e.g. , Letsinger et al, Proc. Natl Acad. Sci. U.S.A. 55:6553-6556 (1989); Lemaitre et al, Proc. Natl Acad. Sci. 54:648- 652 (1987); PCT Publication No. WO88/09810, published December 15, 1988) or the blood-brain barrier (see, e.g. , PCT Publication No. WO89/10134, published April 25, 1988), hybridization-triggered cleavage agents. (See, e.g., Krol et al, BioTechniques 6:958-916 ( 1988)) or intercalating agents. (See, e.g. , Zon, Pharm. Res. 5:539-549 (1988)). To this end, the oligonucleotide may be conjugated to another molecule, e.g., a peptide, hybridization triggered cross-linking agent, transport agent, hybridization-triggered cleavage agent, etc. The antisense oligonucleotide may comprise at least one modified base moiety which is selected from the group including, but not limited to, 5-fluorouracil, 5-bromouracil, 5-chlorouracil, 5-iodouracil, hypoxanthine, xantine, 4-acetylcytosine, 5-(carboxyhydroxylmethyl) uracil, 5-carboxymethylaminomethyl- 2-thiouridine, 5-carboxymethylaminomethyluracil, dihydrouracil, beta-D- galactosylqueosine, inosine, N6-isopentenyladenine, 1-methylguanine, 1-methylinosine, 2,2-dimethylguanine, 2-methyladenine, 2-methylguanine, 3-methylcytosine, 5-methylcytosine, N6-adenine, 7-methylguanine, 5-methylaminomethyluracil, 5-methoxyaminomethyl-2-thiouracil, beta- D-mannosylqueosine, 5ø-methoxycarboxymethyluracil, 5-methoxyuracil, 2-methylthio-N6-isopentenyladenine, uracil-5-oxyacetic acid (v), wybutoxosine, pseudouracil, queosine, 2-thiocytosine, 5-methyl-2-thiouracil, 2-thiouracil, 4-thiouracil, 5-methyluracil, uracil-5-oxyacetic acidmethylester, uracil-5-oxyacetic acid (v), 5-methyl-2-thiouracil, 3-(3-amino-3-N-2-carboxypropyl) uracil, (acp3)w, and 2,6-diaminopurine. The antisense oligonucleotide may also comprise at least one modified sugar moiety selected from the group including, but not limited to, arabinose, 2-fluoroarabinose, xylulose, and hexose. In yet another embodiment, the antisense oligonucleotide comprises at least one modified phosphate backbone selected from the group including, but not limited to, a phosphorothioate, a phosphorodithioate, a phosphoramidothioate, a phosphoramidate, a phosphordiamidate, a methylphosphonate, an alkyl phosphotriester, and a formacetal or analog thereof. In yet another embodiment, the antisense oligonucleotide is an α-anomeric oligonucleotide. An α-anomeric oligonucleotide forms specific double-stranded hybrids with complementary RNA in which, contrary to the usual β-units, the strands run parallel to each other (Gautier et al, Nucl. Acids Res. 75:6625-6641 (1987)). The oligonucleotide is a 20-0-methylribonucleotide (Inoue et al, Nucl. Acids Res. 75:6131-6148 (1987)), or a chimeric RNA-DNA analogue (Inoue el al, FEBS ett. 275:327-330 (1987)). Polynucleotides ofthe invention may be synthesized by standard methods known in the art, e.g. by use of an automated DNA synthesizer (such as are commercially available from Biosearch, Applied Biosystems, etc.). As examples, phosphorothioate oligonucleotides may be synthesized by the method_of Stein et al. (Nucl. Acids Res. 16:3209 (1988)), methylphosphonate oligonucleotides can be prepared by use of controlled pore glass polymer supports (Sarin et al, Proc. Natl. Acad. Sci. U.S.A. 55:7448-7451 (1988)), etc. While antisense nucleotides complementary to the TRID coding region sequence could be used, those complementary to the transcribed untranslated region are most preferred. Potential antagonists according to the invention also include catalytic RNA, or a ribozyme (See, e.g. , PCT International Publication WO 90/1 1364, published October 4, 1990; Sarver et al, Science 247: 1222-1225 (1990). While ribozymes that cleave mRNA at site specific recognition sequences can be used to destroy TRID mRNAs, the use of hammerhead ribozymes is preferred. Hammerhead ribozymes cleave mRNAs at locations dictated by flanking regions that form complementary base pairs with the target mRNA. The sole requirement is that the target mRNA have the following sequence of two bases: 5'-UG-3'. The construction and production of hammerhead ribozymes is well known in the art and is described more fully in Haseloff and Gerlach, Nature 554:585-591 (1988). There are numerous potential hammerhead ribozyme cleavage sites within the nucleotide sequence of TRID (SEQ ID NO: l). Preferably, the ribozyme is engineered so that the cleavage recognition site is located near the 5' end of the TRID mRNA; i.e., to increase efficiency and minimize the intracellular accumulation of non-functional mRNA transcripts. As in the antisense approach, the ribozymes of the invention can be composed of modified oligonucleotides (e.g.. for improved stability, targeting, etc.) and should be delivered to cells which express TRID in vivo. DNA constructs encoding the ribozyme may be introduced into the cell in the same manner as described above for the introduction of antisense encoding DNA. A preferred method of delivery involves using a DNA construct "encoding" the ribozyme under the control of a strong constitutive promoter, such as, for example, pol III or pol II promoter, so that transfected cells will produce sufficient quantities of the ribozyme to destroy endogenous TRID messages and inhibit translation. Since ribozymes unlike antisense molecules, are catalytic, a lower intracellular concentration is required for efficiency. Endogenous gene expression can also be reduced by inactivating or "knocking out" the TRID gene and/or its promoter using targeted homologous recombination. (E.g., see Smithies et al, Nature 317:230-234 (1985); Thomas & Capecchi, Cell 57:503-512 (1987); Thompson et al, Cell 5:313-321 (1989); each of which is incoφorated by reference herein in its entirety). For example, a mutant, non-functional polynucleotide ofthe invention (or a completely unrelated DNA sequence) flanked by DNA homologous to the endogenous polynucleotide sequence (either the coding regions or regulatory regions ofthe gene) can be used, with or without a selectable marker and/or a negative selectable marker, to transfect cells that express polypeptides of the invention in vivo. In another embodiment, techniques known in the art are used to generate knockouts in cells that contain, but do not express the gene of interest. Insertion of the DNA construct, via targeted homologous recombination, results in inactivation ofthe targeted gene. Such approaches are particularly suited in research and agricultural fields where modifications to embryonic stem cells can be used to generate animal offspring with an inactive targeted gene (e.g.. see Thomas & Capecchi (1987) and Thompson (1989), supra). However this approach can be routinely adapted for use in humans provided the recombinant DNA constructs are directly administered or targeted to the required site in vivo using appropriate viral vectors that will be apparent to those of skill in the art. The contents of each ofthe documents recited in this paragraph is herein incorporated by reference in its entirety. Further agonist according to the present invention include soluble forms of TRID, i.e., TRID fragments that include the ligand binding domain from the extracellular region of the full-length receptor. Such soluble forms of the receptor, which may be naturally occurring or synthetic, antagonize TNFR mediated signaling by competing with the cell surface TNFR for binding to TNF- family ligands. Thus, soluble forms ofthe TRID receptor that include the ligand binding domain are novel cytokines capable of inhibiting apoptosis induced by TNF-family ligands. Other such cytokines are known in the art and include Fas B (a soluble form of the mouse Fas receptor) that acts physiologically to limit apoptosis induced by Fas ligand (Hughes, D.P. and Crispe, I.N., J. Exp. Med. 752: 1395-1401 (1995)). Proteins and other compounds which bind the extracellular domains are also candidate agonist and antagonist according to the present invention. Such binding compounds can be "captured" using the yeast two-hybrid system (Fields and Song, Nature 540:245-246 (1989)). A modified version of the yeast two- hybrid system has been described by Roger Brent and his colleagues (Gyuris, J. et al, Cell 75:791-803 (1993); Zervos, A.S. et al, Cell 72:223-232 (1993)). By a "TNF-family ligand" is intended naturally occurring, recombinant, and synthetic ligands that are capable of binding to a member of the TNF receptor family and inducing and/or blocking the ligand/receptor signaling pathway. Members ofthe TNF ligand family include, but are not limited to, soluble forms of TNF-α, lymphotoxin-alpha (LT-α, also known as TNF-β), LT-β (found in complex heterotrimer LT-α2-β), OPGL, FasL, TRAIL, CD27L, CD30L, CD40L, 4-1BBL, DcR3, OX40L, TNF-γ (International Publication No. WO 96/14328), AIM-I (International Publication No. WO 97/33899), AIM-II (International Publication No. WO 97/3491 1), APRIL (J Exp. Med. 755(6): 1 185-1 190), endokine-alpha (International Publication No. WO 98/07880), TR6 (International Publication No. WO 98/30694), OPG, OX40, and nerve growth factor (NGF), and soluble forms of Fas, CD30, CD27, CD40 and 4-IBB, TR2 (International Publication No. WO 96/34095), DR3 (International Publication No. WO 97/33904), DR4 (International Publication No. WO 98/32856), TR6 (International Publication No. WO 98/30694), TR7 (International Publication No. WO 98/41629), TRANK, TR9 (International Publication No. WO 98/56892), TRIO (International Publication No. WO 98/54202), 312C2 (International Publication No. WO 98/06842), and TR12, and soluble forms CD154, CD70, and CD153. TNF-α has been shown to protect mice from infection with heφes simplex virus type l (HSV-l) (Rossol-Vothetα/., J.Ge 7. Virol. 72:143-147 (1991)). The mechanism ofthe protective effect of TNF-α is unknown but appears to involve neither interferons nor NK cell killing. One member ofthe family has been shown to mediate HSV- 1 entry into cells (Montgomery et al. , Eur. Cytokine Newt. 7: 159 (1996)). Further, antibodies specific for the extracellular domain of this block HSV-1 entry into cells. Thus, TRID antagonists ofthe present invention include both TRID amino acid sequences and antibodies capable of preventing mediated viral entry into cells. Such sequences and antibodies can function by either competing with cell surface localized for binding to virus or by directly blocking binding of virus to cell surface receptors. As indicated polyclonal and monoclonal antibody agonist or antagonist according to the present invention can be raised according to the methods disclosed in Tartaglia, L.A., and Goeddel, D.V., J. Biol Chem. 267 (7) -.4304-4301 (1992); Tartaglia, L.A. et al, Cell 75:213-216 (1993), and PCT Application WO 94/09137 (the contents of each of these three applications are herein incoφorated by reference in their entireties), and are preferably specific to polypeptides ofthe invention having the amino acid sequence of SEQ ID NO:2. The term "antibody" (Ab) or "monoclonal antibody" (mAb) as used herein is meant to include intact molecules as well as fragments thereof (such as, for example, Fab and F(ab') 2 fragments) which are capable of binding an antigen. Fab and F (ab') 2 fragments lack the Fc fragment of intact antibody, clear more rapidly from the circulation, and may have less non-specific tissue binding of an intact antibody (Wahl et al, J. Nucl. Med. 24:316-325 (1983)). Antibodies according to the present invention may be prepared by any of a variety of standard methods, such as those described above and known in the art, using TRID receptor immunogens ofthe present invention. Such TRID receptor immunogens include the TRID protein shown in SEQ ID NO:2 (which may or may not include a leader sequence) and polypeptide fragments of the receptor comprising, or alternatively consisting of. the ligand binding, extracellular, transmembrane, the intracellular domains of TRID, or any combination thereof. Gene Therapy In a specific embodiment, nucleic acids comprising sequences encoding antibodies or functional derivatives thereof, are administered to treat, inhibit and/or prevent a disease or disorder associated with aberrant expression and/or activity of a polypeptide ofthe invention, by way of gene therapy. Gene therapy refers to therapy performed by the administration to a subject of an expressed or expressible nucleic acid. In this embodiment ofthe invention, the nucleic acids produce their encoded protein that mediates a therapeutic effect. Any of the methods for gene therapy available in the art can be used according to the present invention. Exemplary methods are described below. For general reviews ofthe methods of gene therapy, see Goldspiel et al, 1993, Clinical Pharmacy 12:488-505; Wu and Wu, 1991, Biotherapy 3:87-95; Tolstoshev, 1993, Ann. Rev. Pharmacol. Toxicol. 32:573-596; Mulligan, 1993, Science 260:926-932; and Morgan and Anderson, 1993, Ann. Rev. Biochem. 62:191-217; May, 1993, TIBTECH 11(5):155-215). Methods commonly known in the art of recombinant DNA technology which can be used are described in Ausubel et al. (eds.), 1993, Current Protocols in Molecular Biology, John Wiley & Sons. NY; and Kriegler, 1990, Gene Transfer and Expression, A Laboratory Manual, Stockton Press, NY. In a preferred aspect, the compound comprises nucleic acid sequences encoding an antibody, said nucleic acid sequences being part of expression vectors that express the antibody or fragments or chimeric proteins or heavy or light chains thereof in a suitable host. In particular, such nucleic acid sequences have promoters operably linked to the antibody coding region, said promoter being inducible or constitutive, and, optionally, tissue- specific. In another particular embodiment, nucleic acid molecules are used in which the antibody coding sequences and any other desired sequences are flanked by regions that promote homologous recombination at a desired site in the genome, thus providing for intrachromosomal expression ofthe antibody nucleic acids (Koller and Smithies, 1989, Proc. Natl. Acad. Sci. USA 86:8932-8935; Zijlstra et al, 1989, Nature 342:435-438). In specific embodiments, the expressed antibody molecule is a single chain antibody; alternatively, the nucleic acid sequences include sequences encoding both the heavy and light chains, or fragments thereof, ofthe antibody. Delivery ofthe nucleic acids into a patient may be either direct, in which case the patient is directly exposed to the nucleic acid or nucleic acid- carrying vectors, or indirect, in which case, cells are first transformed with the nucleic acids in vitro, then transplanted into the patient. These two approaches are known, respectively, as in vivo or ex vivo gene therapy. In a specific embodiment, the nucleic acid sequences are directly administered in vivo, where it is expressed to produce the encoded product. This can be accomplished by any of numerous methods known in the art, e.g. , by constructing them as part of an appropriate nucleic acid expression vector and administering it so that they become intracellular, e.g. , by infection using defective or attenuated retrovirals or other viral vectors (see U.S. Patent No. 4,980,286), or by direct injection of naked DNA. or by use of microparticle bombardment (e.g., a gene gun; Biolistic, Dupont), or coating with lipids or cell-surface receptors or transfecting agents, encapsulation in liposomes, microparticles, or microcapsules, or by administering them in linkage to a peptide which is known to enter the nucleus, by administering it in linkage to a ligand subject to receptor- mediated endocytosis (see, e.g., Wu and Wu, 1987, J. Biol. Chem. 262:4429- 4432) (which can be used to target cell types specifically expressing the receptors), etc. In another embodiment, nucleic acid-ligand complexes can be formed in which the ligand comprises a fusogenic viral peptide to disrupt endosomes. allowing the nucleic acid to avoid lysosomal degradation. In yet another embodiment, the nucleic acid can be targeted in vivo for cell specific uptake and expression, by targeting a specific receptor (see, e.g., PCT Publications WO 92/06180 dated April 16, 1992 (Wu et al); WO 92/22635 dated December 23, 1992 (Wilson et al); WO92/20316 dated November 26, 1992 (Findeis et al); WO93/14188 dated July 22, 1993 (Clarke et al), WO 93/20221 dated October 14, 1993 (Young)). Alternatively, the nucleic acid can be introduced intracellularly and incorporated within host cell DNA for expression, by homologous recombination (Koller and Smithies, 1989, Proc. Natl. Acad. Sci. USA 86:8932-8935; Zijlstra et al, 1989, Nature 342:435-438). In a specific embodiment, viral vectors that contains nucleic acid sequences encoding an antibody ofthe invention are used. For example, a retroviral vector can be used (see Miller et al, 1993, Meth. Enzymol. 217:581-599). These retroviral vectors have been to delete retroviral sequences that are not necessary for packaging ofthe viral genome and integration into host cell DNA. The nucleic acid sequences encoding the antibody to be used in gene therapy are cloned into one or more vectors, which facilitates delivery of the gene into a patient. More detail about retroviral vectors can be found in Boesen et al, 1994, Biotherapy 6:291-302, which describes the use of a retroviral vector to deliver the mdrl gene to hematopoietic stem cells in order to make the stem cells more resistant to chemotherapy. Other references illustrating the use of retroviral vectors in gene therapy are: Clowes et al, 1994, J. Clin. Invest. 93:644-651 ; Kiem et al, 1994, Blood 83 : 1467-1473; Salmons and Gunzberg, 1993, Human Gene Therapy 4: 129- 141 ; and Grossman and Wilson, 1993, Curr. Opin. in Genetics and Devel. 3: 1 10- 1 14. Adenoviruses are other viral vectors that can be used in gene therapy. Adenoviruses are especially attractive vehicles for delivering genes to respiratory epithelia. Adenoviruses naturally infect respiratory epithelia where they cause a mild disease. Other targets for adenovirus-based delivery systems are liver, the central nervous system, endothelial cells, and muscle. Adenoviruses have the advantage of being capable of infecting non-dividing cells. Kozarsky and Wilson, 1993, Current Opinion in Genetics and Development 3 :499-503 present a review of adenovirus-based gene therapy. Bout et a , 1994, Human Gene Therapy 5:3- 10 demonstrated the use of adenovirus vectors to transfer genes to the respiratory epithelia of rhesus monkeys. Other instances ofthe use of adenoviruses in gene therapy can be found in Rosenfeld et al. , 1991, Science 252:431-434; Rosenfeld et al, 1992, Cell 68: 143- 155; Mastrangeli et al, 1993, J. Clin. Invest. 91 :225- 234; PCT Publication WO94/12649; and Wang etal. , 1995, Gene Therapy 2:775- 783. In a preferred embodiment, adenovirus vectors are used. Adeno-associated virus (AAV) has also been proposed for use in gene therapy (Walsh etal, 1993, Proc. Soc. Exp. Biol. Med.204:289-300; U.S. Patent No. 5,436,146). Another approach to gene therapy involves transferring a gene to cells in tissue culture by such methods as electroporation, lipofection, calcium phosphate mediated transfection, or viral infection. Usually, the method of transfer includes the transfer of a selectable marker to the cells. The cells are then placed under selection to isolate those cells that have taken up and are expressing the transferred gene. Those cells are then delivered to a patient. In this embodiment, the nucleic acid is introduced into a cell prior to administration in vivo ofthe resulting recombinant cell. Such introduction can be carried out by any method known in the art, including but not limited to transfection, electroporation, microinjection. infection with a viral or bacteriophage vector containing the nucleic acid sequences, cell fusion, chromosome-mediated gene transfer, microcell-mediated gene transfer, spheroplast fusion, etc. Numerous techniques are known in the art for the introduction of foreign genes into cells (see, e.g., Loeffler and Behr, 1993, Meth. Enzymol 217:599-618; Cohen et al, 1993, Meth. Enzymol 277:618-644; Cline, 1985, Pharmac. Ther. 29:69-92) and may be used in accordance with the present invention, provided that the necessary developmental and physiological functions of the recipient cells are not disrupted. The technique should provide for the stable transfer ofthe nucleic acid to the cell, so that the nucleic acid is expressible by the cell and preferably heritable and expressible by its cell progeny. The resulting recombinant cells can be delivered to a patient by various methods known in the art. Recombinant blood cells (e.g. , hematopoietic stem or progenitor cells) are preferably administered intravenously. The amount of cells envisioned for use depends on the desired effect, patient state, etc., and can be determined by one skilled in the art. Cells into which a nucleic acid can be introduced for puφoses of gene therapy encompass any desired, available cell type, and include but are not limited to epithelial cells, endothelial cells, keratinocytes, fibroblasts, muscle cells, hepatocytes; blood cells such as T-lymphocytes, B-lymphocytes, monocytes, macrophages, neutrophils, eosinophils, megakaryocytes, granulocytes; various stem or progenitor cells, in particular hematopoietic stem or progenitor cells, e.g. , as obtained from bone marrow, umbilical cord blood, peripheral blood, fetal liver, etc. In a preferred embodiment, the cell used for gene therapy is autologous to the patient. In an embodiment in which recombinant cells are used in gene therapy, nucleic acid sequences encoding an antibody are introduced into the cells such that they are expressible by the cells or their progeny, and the recombinant cells are then administered in vivo for therapeutic effect. In a specific embodiment, stem or progenitor cells are used. Any stem and/or progenitor cells which can be isolated and maintained in vitro can potentially be used in accordance with this embodiment ofthe present invention (see, e.g., PCT Publication WO 94/08598, dated April 28, 1994; Stemple and Anderson, 1992, Cell 71 :973-985; Rheinwald, 1980, Meth. Cell Bio. 27-4:229; and Pittelkow and Scott. 1986, Mayo Clinic Proc. 61:111). In a specific embodiment, the nucleic acid to be introduced for puφoses of gene therapy comprises an inducible promoter operably linked to the coding region, such that expression ofthe nucleic acid is controllable by controlling the presence or absence ofthe appropriate inducer of transcription. Modes of Administration The invention provides methods of treatment, inhibition and prophylaxis by administration to a subject of an effective amount of a compound or pharmaceutical composition of the invention, preferably an antibody of the invention. In a preferred aspect, the compound is substantially purified (e.g., substantially free from substances that limit its effect or produce undesired side- effects). The subject is preferably an animal, including but not limited to animals such as cows, pigs, horses, chickens, cats, dogs, etc., and is preferably a mammal, and most preferably human. Formulations and methods of administration that can be employed when the compound comprises a nucleic acid or an immunoglobulin are described above; additional appropriate formulations and routes of administration can be selected from among those described herein below. The agonist or antagonists described herein can be administered in vitro, ex vivo, or in vivo to cells which express the receptor ofthe present invention. By administration of an "effective amount" of an agonist or antagonist is intended an amount ofthe compound that is sufficient to enhance or inhibit a cellular response to a TNF-family ligand and include polypeptides. In particular, by administration of an "effective amount" of an agonist or antagonists is intended an amount effective to enhance or inhibit TRID activity. Of course, where apoptosis is to be enhanced, a TRID antagonist according to the present invention can be co- administered with a TNF-family ligand. One of ordinary skill will appreciate that effective amounts of an agonist or antagonist can be determined empirically and may be employed in pure form or in pharmaceutically acceptable salt, ester or prodrug form. The agonist or antagonist may be administered in compositions in combination with one or more pharmaceutically acceptable excipients. It will be understood that, when administered to a human patient, the total daily usage ofthe compounds and compositions ofthe present invention will be decided by the attending physician within the scope of sound medical judgement. The specific therapeutically effective dose level for any particular patient will depend upon factors well known in the medical arts. As a general proposition, the total pharmaceutically effective amount of TRID polypeptide administered parenterally per dose will be in the range of about 1 μg/kg/day to 10 mg/kg/day of patient body weight, although, as noted above, this will be subject to therapeutic discretion. More preferably, this dose is at least 0.01 mg/kg/day, and most preferably for humans between about 0.01 and 1 mg/kg/day. If given continuously, the TRID agonist or antagonist is typically administered at a dose rate of about 1 μg/kg/hour to about 50 μg/kg/hour, either by 1-4 injections per day or by continuous subcutaneous infusions, for example, using a mini-pump. An intravenous bag solution may also be employed. Dosaging may also be arranged in a patient specific manner to provide a predetermined concentration of an agonist or antagonist in the blood, as determined by the RIA technique. Thus patient dosaging may be adjusted to achieve regular on-going trough blood levels, as measured by RIA, on the order of from 50 to 1000 ng/ml, preferably 150 to 500 ng/ml. Pharmaceutical compositions of the present invention for parenteral injection can comprise pharmaceutically acceptable sterile aqueous or nonaqueous solutions, dispersions, suspensions or emulsions as well as sterile powders for reconstitution into sterile injectable solutions or dispersions just prior to use. In addition to soluble TRID polypeptides, TRID polypeptides containing the transmembrane region can also be used when appropriately solubilized by including detergents, such as CHAPS or NP-40, with buffer. The compounds or pharmaceutical compositions of the invention are preferably tested in vitro, and then in vivo for the desired therapeutic or prophylactic activity, prior to use in humans. For example, in vitro assays to demonstrate the therapeutic or prophylactic utility of a compound or pharmaceutical composition include, the effect of a compound on a cell line or a patient tissue sample. The effect ofthe compound or composition on the cell line and/or tissue sample can be determined utilizing techniques known to those of skill in the art including, but not limited to. rosette formation assays and cell lysis assays. In accordance with the invention, in vitro assays which can be used to determine whether administration of a specific compound is indicated, include in vitro cell culture assays in which a patient tissue sample is grown in culture, and exposed to or otherwise administered a compound, and the effect of such compound upon the tissue sample is observed. The present invention also provides pharmaceutical compositions. Such compositions comprise a therapeutically effective amount of a compound, and a pharmaceutically acceptable carrier. In particular embodiments, pharmaceutical compositions are provided comprising a TRID agonist or antagonist and a pharmaceutically acceptable carrier or excipient, which may be administered orally, rectally, parenterally, intracistemally, intravaginally, intraperitoneally, topically (as by powders, ointments, drops or transdermal patch), bucally, or as an oral or nasal spray. Importantly, by co-administering a TRID antagonist and a TNF-family ligand, clinical side effects can be reduced by using lower doses of both the ligand and the antagonist. It will be understood that the antagonist can be "co-administered" either before, after, or simultaneously with the TNF-family ligand, depending on the exigencies of a particular therapeutic application. By "pharmaceutically acceptable carrier" is meant a non-toxic solid, semisolid or liquid filler, diluent, encapsulating material or formulation auxiliary of any type. In a specific embodiment, the term "pharmaceutically acceptable" means approved by a regulatory agency ofthe Federal or a state government or listed in the U.S. Pharmacopeia or other generally recognized pharmacopeia for use in animals, and more particularly in humans. The term "parenteral" as used herein refers to modes of administration which include intravenous, intramuscular, intraperitoneal, intrasternal, subcutaneous and intraarticular injection and infusion. The term "carrier" refers to a diluent, adjuvant, excipient, or vehicle with which the therapeutic is administered. Such pharmaceutical carriers can be sterile liquids, such as water and oils, including those of petroleum, animal, vegetable or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil and the like. Water is a preferred carrier when the pharmaceutical composition is administered intravenously. Saline solutions and aqueous dextrose and glycerol solutions can also be employed as liquid carriers, particularly for injectable solutions. Suitable pharmaceutical excipients include starch, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene, glycol. water, ethanol and the like. The composition, if desired, can also contain minor amounts of wetting or emulsifying agents, or pH buffering agents. These compositions can take the form of solutions, suspensions, emulsion, tablets, pills, capsules, powders, sustained- release formulations and the like. The composition can be formulated as a suppository, with traditional binders and carriers such as triglycerides. Oral formulation can include standard carriers such as pharmaceutical grades of mannitol, lactose, starch, magnesium stearate, sodium saccharine, cellulose, magnesium carbonate, etc. Examples of suitable pharmaceutical carriers are described in "Remington's Pharmaceutical Sciences" by E.W. Martin. Such compositions will contain a therapeutically effective amount of the compound, preferably in purified form, together with a suitable amount of carrier so as to provide the form for proper administration to the patient. The formulation should suit the mode of administration. In a preferred embodiment, the composition is formulated in accordance with routine procedures as a pharmaceutical composition adapted for intravenous administration to human beings. Typically, compositions for intravenous administration are solutions in sterile isotonic aqueous buffer. Where necessary, the composition may also include a solubilizing agent and a local anesthetic such as lignocaine to ease pain at the site ofthe injection. Generally, the ingredients are supplied either separately or mixed together in unit dosage form, for example, as a dry lyophilized powder or water free concentrate in a hermetically sealed container such as an ampule or sachette indicating the quantity of active agent. Where the composition is to be administered by infusion, it can be dispensed with an infusion bottle containing sterile pharmaceutical grade water or saline. Where the composition is administered by injection, an ampule of sterile water for injection or saline can be provided so that the ingredients may be mixed prior to administration. The compounds ofthe invention can be formulated as neutral or salt forms. Pharmaceutically acceptable salts include those formed with anions such as those derived from hydrochloric, phosphoric, acetic, oxalic, tartaric acids, etc., and those formed with cations such as those derived from sodium, potassium, ammonium, calcium, ferric hydroxides, isopropylamine, triethylamine, 2- ethylamino ethanol, histidine, procaine. etc. The TRID polypeptide is also suitably administered by sustained-release systems. Suitable examples of sustained-release compositions include semipermeable polymer matrices in the form of shaped articles, e.g., films, or mirocapsules. Sustained-release matrices include polylactides (U.S. Pat. No. 3,773,919, EP 58,481), copolymers of L-glutamic acid and gamma-ethyl-L- glutamate (Sidman, U. et al., Biopolymers 22:541-556 (1983)), poly (2- hydroxy ethyl methacrylate) (R. Langer et al., J. Biomed. Mater. Res. 75:167-277 (1981), andR. Langer, Chem. Tech. 72:98-105 (1982)), ethylene vinyl acetate (R. Langer et al., Id.) or poly-D- (-)-3-hydroxybutyric acid (EP 133,988). Sustained- release TRID polypeptide compositions also include liposomally entrapped TRID polypeptides. Liposomes containing TRID polypeptides are prepared by methods known per se: DE 3,218,121 ; Epstein et al., Proc. Natl. Acad. Sci. (USA) 82:3688-3692 (1985); Hwang et al., Proc. Natl. Acad. Sci. (USA) 77:4030-4034 (1980); EP 52,322; EP 36,676; EP 88.046; EP 143,949; EP 142.641 ; Japanese Pat. Appl. 83-1 18008; U.S. Pat. Nos. 4,485,045 and 4,544,545; and EP 102,324. Ordinarily, the liposomes are ofthe small (about 200-800 Angstroms) unilamellar type in which the lipid content is greater than about 30 mol. percent cholesterol, the selected proportion being adjusted for the optimal TNFR polypeptide therapy. The carrier suitably contains minor amounts of additives such as substances that enhance isotonicity and chemical stability. Such materials are non- toxic to recipients at the dosages and concentrations employed, and include buffers such as phosphate, citrate, succinate, acetic acid, and other organic acids or their salts; antioxidants such as ascorbic acid; low molecular weight (less than about ten residues) polypeptides, e.g. , polyarginine or tripeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as poly vinylpyrrolidone; amino acids, such as glycine, glutamic acid, aspartic acid, or arginine; monosaccharides, disaccharides, and other carbohydrates including cellulose or its derivatives, glucose, manose, or dextrins; chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; counterions such as sodium; and/or nonionic surfactants such as polysorbates, poloxamers, or PEG. The TRID polypeptide is typically formulated in such vehicles at a concentration of about 0.1 mg/ml to 100 mg/ml, preferably 1-10 mg/ml, at a pH of about 3 to 8. It will be understood that the use of certain of the foregoing excipients, carriers, or stabilizers will result in the formation of TRID polypeptide salts. TRID polypeptides to be used for therapeutic administration must be sterile. Sterility is readily accomplished by filtration through sterile filtration membranes (e.g., 0.2 micron membranes). Therapeutic TRID polypeptide compositions generally are placed into a container having a sterile access port, for example, an intravenous solution bag or vial having a stopper pierceable by a hypodermic injection needle. TRID polypeptides ordinarily will be stored in unit or multi-dose containers, for example, sealed ampoules or vials, as an aqueous solution or as a lyophilized formulation for reconstitution. As an example of a lyophilized formulation, 10-ml vials are filled with 5 ml of sterile-filtered 1% (w/v) aqueous TRID polypeptide solution, and the resulting mixture is lyophilized. The infusion solution is prepared by reconstituting the lyophilized TRID polypeptide using bacteriostatic Water- for-Injection. As indicated above, the compositions ofthe invention may be administered alone or in combination with other therapeutic agents. Therapeutic agents that may be administered in combination with the compositions of the invention, include but are not limited to, other members ofthe TNF family, chemotherapeutic agents, antibiotics, steroidal and non-steroidal anti-inflammatories, conventional immunotherapeutic agents, cytokines, chemokines and/or growth factors. Combinations may be administered either concomitantly, e.g., as an admixture, separately but simultaneously or concurrently; or sequentially. This includes presentations in which the combined agents are administered together as a therapeutic mixture, and also procedures in which the combined agents are administered separately but simultaneously, e.g.. as through separate intravenous lines into the same individual. Administration "in combination" further includes the separate administration of one of the compounds or agents given first, followed by the second. In one embodiment, the compositions ofthe invention are administered in combination with other members ofthe TNF family. TNF, TNF-related or TNF- like molecules that may be administered with the compositions ofthe invention include, but are not limited to, soluble forms of TNF-alpha, lymphotoxin-alpha (LT-alpha, also known as TNF-beta), LT-beta (found in complex heterotrimer LT- alpha2-beta), OPGL, FasL, CD27L, CD30L, CD40L, 4-1BBL, DcR3, OX40L, TNF-gamma (International Publication No. WO 96/14328), (International Publication No. WO 96/14328), TNF-γ-α, TNF-γ-β (International Publication No. WO 00/08139), TRAIL, AIM-II (International Publication No. WO 97/3491 1), APRIL (J. Exp. Med. 188(6): 1 185-1 190), endokine-alpha (International Publication No. WO 98/07880), TR6 (International Publication No. WO 98/30694), OPG, and neutrokine-alpha (International Publication No. WO 98/18921, OX40, and nerve growth factor (NGF), and soluble forms of Fas, CD30, CD27, CD40 and 4-IBB, TR2 (International Publication No. WO 96/34095), DR3 (International Publication No. WO 97/33904), DR4 (International Publication No. WO 98/32856, TR6 (International Publication No. WO 98/30694), TR7 (International Publication No. WO 98/41629), TRANK, TR9 (International Publication No. WO 98/56892), TRIO (International Publication No. WO 98/54202), 312C2 (International Publication No. WO 98/06842), and TR12, AIM-I (International Publication No. WO 97/33899), and soluble forms CD 154, CD70, and CD 153. In another embodiment, the compositions ofthe invention are administered in combination with CD40 ligand (CD40L), a soluble form of CD40L (e.g., AVREND™), biologically active fragments, variants, or derivatives of CD40L, anti-CD40L antibodies (e.g., agonistic or antagonistic antibodies), and/or anti- CD40 antibodies (e.g., agonistic or antagonistic antibodies). In yet another embodiment, the compositions of the invention are administered in combination with one, two, three, four, five, or more of the following compositions: tacrolimus (Fujisawa), thalidomide (e.g. , Celgene), anti- Tac(Fv)-PE40 (e.g., Protein Design Labs), inolimomab (Biotest), MAK-195F (Knoll), ASM-981 (Novartis), interleukin- 1 receptor (e.g. , Immunex), interleukin- 4 receptor (e.g. , Immunex), ICM3 (ICOS), BMS-188667 (Bristol-Myers Squibb), anti-TNF Ab (e.g. , Therapeutic antibodies), CG-1088 (Celgene), anti-B7 monoclonal antibody (e.g., Innogetics), MEDI-507 (BioTransplant), ABX-CBL (Abgenix). According to the invention, a patient susceptible to both Fas ligand (Fas-L) mediated and TRAIL mediated cell death may be treated with both an agent that inhibits TRAIL/TRAIL-R interactions and an agent that inhibits Fas-L/Fas interactions. Suitable agents for blocking binding of Fas-L to Fas include, but are not limited to, soluble Fas polypeptides; oligomeric forms of soluble Fas polypeptides (e.g., dimers of sFas/Fc); anti-Fas antibodies that bind Fas without transducing the biological signal that results in apoptosis; anti-Fas-L antibodies that block binding of Fas-L to Fas; and muteins of Fas-L that bind Fas but do not transduce the biological signal that results in apoptosis. Preferably, the antibodies employed according to this method are monoclonal antibodies. Examples of suitable agents for blocking Fas-L/Fas interactions, including blocking anti-Fas monoclonal antibodies, are described in WO 95/10540, hereby incoφorated by reference. In certain embodiments, compositions ofthe invention are administered in combination with antiretroviral agents, nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, and/or protease inhibitors. Nucleoside reverse transcriptase inhibitors that may be administered in combination with the compositions ofthe invention, include, but are not limited to, RETROVIR™ (zidovudine/AZT), VIDEX™ (didanosine/ddl), HIVID™ (zalcitabine/ddC), ZERIT™ (stavudine/d4T), EPIVIR™ (lamivudine/3TC), and COMBIVIR™ (zidovudine/lamivudine). Non-nucleoside reverse transcriptase inhibitors that may be administered in combination with the compositions ofthe invention, include, but are not limited to, VIRAMUNE™ (nevirapine), RESCRIPTOR™ (delavirdine), and SUSTIVA™ (efavirenz). Protease inhibitors that may be administered in combination with the compositions ofthe invention, include, but are not limited to, CRIXIVAN™ (indinavir), NORVIR™ (ritonavir), INVIRASE™ (saquinavir), and VIRACEPT™ (nelfinavir). In a specific embodiment, antiretroviral agents, nucleoside reverse transcriptase inhibitors, non- nucleoside reverse transcriptase inhibitors, and/or protease inhibitors may be used in any combination with compositions of the invention to treat AIDS and/or to prevent or treat HIV infection. In other embodiments, compositions ofthe invention may be administered in combination with anti-opportunistic infection agents. Anti-opportunistic agents that may be administered in combination with the compositions ofthe invention, include, but are not limited to, TRIMETHOPRIM-SULFAMETHOXAZOLE™, DAPSONE™, PENTAMIDINE™, ATOVAQUONE™, ISONIAZID™, RIFAMPIN™, PYRAZIN AMIDE™, ETHAMBUTOL™, RIFABUTIN™, CLARITHROMYCIN™, AZITHROMYCIN™, GANCICLOVIR™, FOSCARNET™, CIDOFOVIR™, FLUCONAZOLE™, ITRACONAZOLE™. KET O C ONAZ O L E™ , A C Y C L O V I R™ , F AM C I C O L V I R™ . PYRIMETHAMINE™, LEUCOVORIN™, NEUPOGEN™ (filgrastim/G-CSF), and LEUKINE™ (sargramostim/GM-CSF). In a specific embodiment, compositions of the invention are used in any combination with TRI METH OPRI M - SULFAMETHOXAZOL E™ , DAP S ONE™ . PENTAMIDINE™, and/or ATOVAQUONE™ to prophylactically treat and/or prevent an opportunistic Pneumocystis carinii pneumonia infection. In another specific embodiment, compositions ofthe invention are used in any combination with ISONIAZID™, RIFAMPIN™, PYRAZINAMIDE™, and/or ETHAMBUTOL™ to prophylactically treat and/or prevent an opportunistic Mycobacterium avium complex infection. In another specific embodiment, compositions ofthe invention are used in any combination with RIFABUTIN™, CLARITHROMYCIN™, and/or AZITHROMYCIN™ to prophylactically treat and/or prevent an opportunistic Mycobacterium tuberculosis infection. In another specific embodiment, compositions ofthe invention are used in any combination with GANCICLOVIR™, FOSCARNET™, and/or CIDOFOVIR™ to prophylactically treat and/or prevent an opportunistic cytomegalovirus infection. In another specific embodiment, compositions of the invention are used in any combination with FLUCONAZOLE™, ITRACONAZOLE™, and/or KETOCONAZOLE™ to prophylactically treat and/or prevent an opportunistic fungal infection. In another specific embodiment, compositions ofthe invention are used in any combination with ACYCLOVIR™ and/or FAMCICOLVIR™ to prophylactically treat and/or prevent an opportunistic heφes simplex virus type I and/or type II infection. In another specific embodiment, compositions ofthe invention are used in any combination with PYRIMETHAMINE™ and/or LEUCOVORIN™ to prophylactically treat and/or prevent an opportunistic Toxoplasma gondii infection. In another specific embodiment, compositions of the invention are used in any combination with LEUCOVORIN™ and/or NEUPOGEN™ to prophylactically treat and/or prevent an opportunistic bacterial infection. In a further embodiment, the compositions of the invention are administered in combination with an antiviral agent. Antiviral agents that may be administered with the compositions ofthe invention include, but are not limited to, acyclovir, ribavirin, amantadine, and remantidine. In a further embodiment, the compositions of the invention are administered in combination with an antibiotic agent. Antibiotic agents that may be administered with the compositions ofthe invention include, but are not limited to, amoxicillin, aminoglycosides, beta-lactam (glycopeptide), beta-lactamases, Clindamycin, chloramphenicol, cephalosporins, ciprofloxacin, ciprofloxacin, erythromycin, fluoroquinolones, macrolides, metronidazole, penicillins, quinolones, rifampin, streptomycin, sulfonamide, tetracyclines, trimethoprim, trimethoprim-sulfamthoxazole, and vancomycin. Conventional nonspecific immunosuppressive agents, that may be administered in combination with the compositions ofthe invention include, but are not limited to, steroids, cyclosporine, cyclosporine analogs, cyclophosphamide methylprednisone, prednisone, azathioprine, FK-506, 15-deoxyspergualin, and other immunosuppressive agents that act by suppressing the function of responding T-cells. In specific embodiments, compositions ofthe invention are administered in combination with immunosuppressants. Immunosuppressants preparations that may be administered with the compositions ofthe invention include, but are not limited to, ORTHOCLONE™ (OKT3), SANDIMMUNE™/NEORAL™/ SANGDYA™ (cyclosporin), PROGRAF™ (tacrolimus), CELLCEPT™ (mycophenolate), Azathioprine, glucorticosteroids, and RAPAMUNE™ (sirolimus). In a specific embodiment, immunosuppressants may be used to prevent rejection of organ or bone marrow transplantation. In an additional embodiment, compositions of the invention are administered alone or in combination with one or more intravenous immune globulin preparations. Intravenous immune globulin preparations that may be administered with the compositions ofthe invention include, but not limited to, GAMMAR™, IVEEGAM™, SANDOGLOBULIN™, GAMMAGARD S/D™, and GAMIMUNE™. In a specific embodiment, compositions of the invention are administered in combination with intravenous immune globulin preparations in transplantation therapy (e.g., bone marrow transplant). In an additional embodiment, the compositions of the invention are administered alone or in combination with an anti-inflammatory agent. Anti- inflammatory agents that may be administered with the compositions of the invention include, but are not limited to, glucocorticoids and the nonsteroidal anti-inflammatories, aminoarylcarboxylic acid derivatives, arylacetic acid derivatives, arylbutyric acid derivatives, arylcarboxylic acids, arylpropionic acid derivatives, pyrazoles, pyrazolones, salicylic acid derivatives, thiazinecarboxamides, e-acetamidocaproic acid, S-adenosylmethionine, 3-amino- 4-hydroxybutyric acid, amixetrine, bendazac, benzydamine, bucolome, difenpiramide, ditazol, emorfazone, guaiazulene, nabumetone, nimesulide, orgotein, oxaceprol, paranyline, perisoxal, pifoxime, proquazone, proxazole, and tenidap. In one embodiment, the compositions of the invention are administered in combination with steroid therapy. Steroids that may be administered in combination with the compositions ofthe invention, include, but are not limited to, oral corticosteroids, prednisone, and methylprednisolone (e.g., IV methylprednisolone). In a specific embodiment, compositions ofthe invention are administered in combination with prednisone. In a further specific embodiment, the compositions of the invention are administered in combination with prednisone and an immunosuppressive agent. Immunosuppressive agents that may be administered with the compositions ofthe invention and prednisone are those described herein, and include, but are not limited to, azathioprine, cylophosphamide, and cyclophosphamide IV. In a another specific embodiment, compositions of the invention are administered in combination with methylprednisolone. In a further specific embodiment, the compositions ofthe invention are administered in combination with methylprednisolone and an immunosuppressive agent. Immunosuppressive agents that may be administered with the compositions of the invention and methylprednisolone are those described herein, and include, but are not limited to, azathioprine, cylophosphamide, and cyclophosphamide IV. In another embodiment, the compositions of the invention are administered in combination with an antimalarial. Antimalarials that may be administered with the compositions ofthe invention include, but are not limited to, hydroxychloroquine, chloroquine, and/or quinacrine. In yet another embodiment, the compositions of the invention are administered in combination with an NSAID. In a nonexclusive embodiment, the compositions of the invention are administered in combination with one, two, three, four, five, ten, or more ofthe following drugs: NRD-101 (Hoechst Marion Roussel), diclofenac (Dimethaid), oxaprozin potassium (Monsanto), mecasermin (Chiron), T-614 (Toyama), pemetrexed disodium (Eli Lilly), atreleuton (Abbott), valdecoxib (Monsanto), eltenac (Byk Gulden), campath, AGM-1470 (Takeda), CDP-571 (Celltech Chiroscience), CM-101 (CarboMed), ML-3000 (Merckle), CB-2431 (KS Biomedix), CBF-BS2 (KS Biomedix), IL-lRa gene therapy (Valentis), JTE-522 (Japan Tobacco), paclitaxel (Angiotech), DW-166HC (Dong Wha), darbufelone mesylate (Warner-Lambert), soluble TNF receptor 1 (synergen; Amgen), IPR- 6001 (Institute for Pharmaceutical Research), trocade (Hoffman-La Roche), EF-5 (Scotia Pharmaceuticals), BIIL-284 (Boehringer Ingelheim), BIIF-1 149 (Boehringer Ingelheim), LeukoVax (Inflammatics), MK-663 (Merck), ST- 1482 (Sigma- Tau), and butixocort propionate (WarnerLambert). In yet another embodiment, the compositions of the invention are administered in combination with one, two, three, four, five or more of the following drugs: methotrexate, sulfasalazine, sodium aurothiomalate, auranofin, cyclosporine, penicillamine, azathioprine, an antimalarial drug (e.g. , as described herein), cyclophosphamide, chlorambucil, gold, ENBREL™ (Etanercept), anti- TNF antibody, and prednisolone. In a more preferred embodiment, the compositions of the invention are administered in combination with an antimalarial. methotrexate, anti-TNF antibody, ENBREL™ and/or suflasalazine. In one embodiment, the compositions ofthe invention are administered in combination with methotrexate. In another embodiment, the compositions of the invention are administered in combination with anti-TNF antibody. In another embodiment, the compositions ofthe invention are administered in combination with methotrexate and anti-TNF antibody. In another embodiment, the compositions ofthe invention are administered in combination with suflasalazine. In another specific embodiment, the compositions of the invention are administered in combination with methotrexate, anti-TNF antibody, and suflasalazine. In another embodiment, the compositions of the invention are administered in combination ENBREL™. In another embodiment, the compositions ofthe invention are administered in combination with ENBREL™ and methotrexate. In another embodiment, the compositions ofthe invention are administered in combination with ENBREL™, methotrexate and suflasalazine. In another embodiment, the compositions of the invention are administered in combination with ENBREL™, methotrexate and suflasalazine. In other embodiments, one or more antimalarials is combined with one of the above- recited combinations. In a specific embodiment, the compositions of the invention are administered in combination with an antimalarial (e.g. , hydroxychloroquine), ENBREL™, methotrexate and suflasalazine. In another specific embodiment, the compositions of the invention are administered in combination with an antimalarial (e.g. , hydroxychloroquine), sulfasalazine, anti- TNF antibody, and methotrexate. In another embodiment, compositions ofthe invention are administered in combination with a chemotherapeutic agent. Chemotherapeutic agents that may be administered with the compositions ofthe invention include, but are not limited to, antibiotic derivatives (e.g. , doxorubicin, bleomycin, daunorubicin, and dactinomycin); antiestrogens (e.g. , tamoxifen); antimetabolites (e.g. , fluorouracil, 5-FU, methotrexate, floxuridine, interferon alpha-2b, glutamic acid, plicamycin, mercaptopurine, and 6-thioguanine); cytotoxic agents (e.g., carmustine, BCNU, lomustine, CCNU, cytosine arabinoside, cyclophosphamide, estramustine, hydroxyurea, procarbazine, mitomycin, busulfan, cis-platin, and vincristine sulfate); hormones (e.g. , medroxyprogesterone, estramustine phosphate sodium, ethinyl estradiol, estradiol, megestrol acetate, methyltestosterone, diethylstilbestrol diphosphate, chlorotrianisene, and testolactone); nitrogen mustard derivatives (e.g., mephalen, chorambucil. mechlorethamine (nitrogen mustard) and thiotepa); steroids and combinations (e.g. , bethamethasone sodium phosphate); and others (e.g., dicarbazine, asparaginase, mitotane, vincristine sulfate, vinblastine sulfate, and etoposide). In an additional embodiment, the compositions of the invention are administered in combination with cytokines. Cytokines that may be administered with the compositions ofthe invention include, but are not limited to, IL-2, IL-3, IL-4, IL-5. IL-6, IL-7, IL-10, IL-12. IL-13, IL-15. anti-CD40, CD40L, IFN- gamma and TNF-alpha. In an additional embodiment, the compositions of the invention are administered in combination with angiogenic proteins. Angiogenic proteins that may be administered with the compositions ofthe invention include, but are not limited to,. Glioma Derived Growth Factor (GDGF), as disclosed in European Patent Number EP-399816; Platelet Derived Growth Factor-A (PDGF-A), as disclosed in European Patent Number EP-6821 10; Platelet Derived Growth Factor-B (PDGF-B), as disclosed in European Patent Number EP-282317; Placental Growth Factor (P1GF), as disclosed in International Publication Number WO 92/06194; Placental Growth Factor-2 (P1GF-2), as disclosed in Hauser et al, Growth Factors, 4:259-268 (1993): Vascular Endothelial Growth Factor (VEGF), as disclosed in International Publication Number WO 90/13649; Vascular Endothelial Growth Factor-A (VEGF-A), as disclosed in European Patent Number EP-506477; Vascular Endothelial Growth Factor-2 (VEGF-2), as disclosed in International Publication Number WO 96/39515; Vascular Endothelial Growth Factor B-186 (VEGF-B186), as disclosed in International Publication Number WO 96/26736; Vascular Endothelial Growth Factor-D (VEGF-D), as disclosed in International Publication Number WO 98/02543; Vascular Endothelial Growth Factor-D (VEGF-D), as disclosed in International Publication Number WO 98/07832; and Vascular Endothelial Growth Factor-E (VEGF-E), as disclosed in German Patent Number DE19639601. The above mentioned references are incoφorated herein by reference herein. In an additional embodiment, the compositions of the invention are administered in combination with Fibroblast Growth Factors. Fibroblast Growth Factors that may be administered with the compositions ofthe invention include, but are not limited to, FGF-1, FGF-2, FGF-3, FGF-4, FGF-5, FGF-6, FGF-7, FGF-8, FGF-9, FGF-10, FGF-1 1 , FGF-12, FGF-13, FGF-14, and FGF-15. In additional embodiments, the compositions of the invention are administered in combination with other therapeutic or prophylactic regimens, such as, for example, radiation therapy. In one embodiment, the compositions ofthe invention are administered in combination with one or more chemokines. In specific embodiments, the compositions ofthe invention are administered in combination with an α(CxC) chemokine selected from the group consisting of gamma-interferon inducible protein- 10 (γIP-10), interleukin-8 (IL-8), platelet factor-4 (PF4), neutrophil activating protein (NAP-2), GRO-α, GRO-β, GRO-γ, neutrophil-activating peptide (ENA-78), granulocyte chemoattractant protein-2 (GCP-2), and stromal cell-derived factor-1 (SDF-1, or pre-B-cell stimulatory factor (PBSF)); and/or a β (CC) selected from the group consisting of: RANTES (regulated on activation, normal T expressed and secreted), macrophage inflammatory protein- 1 alpha (MIP-1 α), macrophage inflammatory protein- 1 beta (MIP-1 β), monocyte chemotactic protein- 1 (MCP-1), monocyte chemotactic protein-2 (MCP-2), monocyte chemotactic protein-3 (MCP-3), monocyte chemotactic protein-4 (MCP-4) macrophage inflammatory protein- 1 gamma (MIP-1 γ), macrophage inflammatory protein-3 alpha (MIP-3 α), macrophage inflammatory protein-3 beta (MIP-3 β), macrophage inflammatory protein-4 (MIP-4/DC-CK-l/PARC), eotaxin, Exodus, and 1-309; and/or the γ(C) chemokine, lymphotactin. Various delivery systems are known and can be used to administer a compound of the invention, e.g., encapsulation in liposomes, microparticles, microcapsules, recombinant cells capable of expressing the compound, receptor- mediated endocytosis (see, e.g., Wu and Wu, 1987, J. Biol Chem. 262:4429- 4432), construction of a nucleic acid as part of a retroviral or other vector, etc. Methods of introduction include but are not limited to intradermal, intramuscular, intraperitoneal, intravenous, subcutaneous, intranasal, epidural, and oral routes. The compounds or compositions may be administered by any convenient route, for example by infusion or bolus injection, by absoφtion through epithelial or mucocutaneous linings (e.g. , oral mucosa, rectal and intestinal mucosa, etc.) and may be administered together with other biologically active agents. Administration can be systemic or local. In addition, it may be desirable to introduce the pharmaceutical compounds or compositions ofthe invention into the central nervous system by any suitable route, including intraventricular and intrathecal injection; intraventricular injection may be facilitated by an intraventricular catheter, for example, attached to a reservoir, such as an Ommaya reservoir. Pulmonary administration can also be employed, e.g., by use of an inhaler or nebulizer, and formulation with an aerosolizing agent. In a specific embodiment, it may be desirable to administer the pharmaceutical compounds or compositions ofthe invention locally to the area in need of treatment; this may be achieved by, for example, and not by way of limitation, local infusion during surgery, topical application, e.g., in conjunction with a wound dressing after surgery, by injection, by means of a catheter, by means of a suppository, or by means of an implant, said implant being of a porous, non-porous, or gelatinous material, including membranes, such as sialastic membranes, or fibers. Preferably, when administering a protein, including an antibody, ofthe invention, care must be taken to use materials to which the protein does not absorb. In another embodiment, the compound or composition can be delivered in a vesicle, in particular a liposome (see Langer, 1990, Science 249:1527-1533; Treat et al. , in Liposomes in the Therapy of Infectious Disease and Cancer, Lopez-Berestein and Fidler (eds.), Liss, New York, pp. 353- 365 (1989); Lopez- Berestein, ibid., pp. 317-327; see generally ibid.) In yet another embodiment, the compound or composition can be delivered in a controlled release system. In one embodiment, a pump may be used (see Langer, supra; Sefton, 1987, CRC Crit Ref Biomed Eng 74:201 ; Buchwald et al , 1980, Surgery 88:507; Saudek et al , 1989, N Engl J Med 527:574). In another embodiment, polymeric materials can be used (see Medical Applications of Controlled Release, Langer and Wise (eds.), CRC Pres., Boca Raton, Florida (1974); Controlled Drug Bioavailability, Drug Product Design and Performance, Smolen and Ball (eds.), Wiley, New York (1984); Ranger and Peppas, J., 1983, Macromol Sci Rev Macromol Chem 25:61 ; see also Levy et al , 1985, Science 225- 190; During et al , 1989, Ann Neurol 25 351 ; Howard et al , 1989, J Neurosurg 71 : 105). In yet another embodiment, a controlled release system can be placed in proximity of the therapeutic target, i e , the brain, thus requiring only a fraction of the systemic dose (see, e g , Goodson, in Medical Applications of Controlled Release, supra, vol. 2, pp. 115-138 (1984)). Other controlled release systems are discussed in the review by Langer (1990, Science 249:1527-1533). In a specific embodiment where the compound ofthe invention is a nucleic acid encoding a protein, the nucleic acid can be administered in vivo to promote expression of its encoded protein, by constructing it as part of an appropriate nucleic acid expression vector and administering it so that it becomes intracellular, e g , by use of a retroviral vector (see U.S. Patent No. 4,980,286), or by direct injection, or by use of microparticle bombardment (e g , a gene gun; Biolistic, Dupont), or coating with lipids or cell-surface receptors or transfecting agents, or by administering it in linkage to a homeobox- like peptide which is known to enter the nucleus (see, e g., Joliot et al , 1991, Proc. Natl. Acad. Sci. USA 88:1864- 1868), etc. Alternatively, a nucleic acid can be introduced intracellularly and incoφorated within host cell DNA for expression, by homologous recombination. The amount ofthe compound ofthe invention which will be effective in the treatment, inhibition and prevention of a disease or disorder associated with aberrant expression and/or activity of a polypeptide of the invention can be determined by standard clinical techniques In addition, in vitro assays may optionally be employed to help identify optimal dosage ranges. The precise dose to be employed in the formulation will also depend on the route of administration, and the seriousness ofthe disease or disorder, and should be decided according to the judgment of the practitioner and each patient's circumstances. Effective doses may be extrapolated from dose-response curves derived from in vitro or animal model test systems. For antibodies, the dosage administered to a patient is typically 0.1 mg/kg to 100 mg/kg ofthe patient's body weight. Preferably, the dosage administered to a patient is between 0.1 mg/kg and 20 mg/kg of the patient's body weight, more preferably 1 mg/kg to 10 mg/kg of the patient's body weight. Generally, human antibodies have a longer half-life within the human body than antibodies from other species due to the immune response to the foreign polypeptides. Thus, lower dosages of human antibodies and less frequent administration is often possible. Further, the dosage and frequency of administration of antibodies ofthe invention may be reduced by enhancing uptake and tissue penetration (e.g. , into the brain) of the antibodies by modifications such as, for example, lipidation. In one embodiment, the invention provides a method of delivering compositions containing the polypeptides of the invention (e.g., compositions containing TRID polypeptides or anti-TRID antibodies (e.g., agonist or antagonist antibodies) associated with heterologous polypeptides, heterologous nucleic acids, toxins, or prodrugs) to targeted cells, expressing the membrane-bound form of TRID on their surface. TRID polypeptides or anti-TRID antibodies of the invention may be associated with heterologous polypeptides, heterologous nucleic acids, toxins, or prodrugs via hydrophobic, hydrophilic, ionic and/or covalent interactions. In one embodiment, the invention provides a method for the specific delivery of compositions ofthe invention to cells by administering polypeptides of the invention (e.g., TRID or anti-TRID antibodies) that are associated with heterologous polypeptides or nucleic acids. In one example, the invention provides a method for delivering a therapeutic protein into the targeted cell. In another example, the invention provides a method for delivering a single stranded nucleic acid (e.g. , antisense or ribozymes) or double stranded nucleic acid (e.g. , DNA that can integrate into the cell's genome or replicate episomally and that can be transcribed) into the targeted cell. In another embodiment, the invention provides a method for the specific destruction of cells (e.g., the destruction of tumor cells) by administering polypeptides ofthe invention (e.g. , TRID polypeptides or anti-TRID antibodies) in association with toxins or cytotoxic prodrugs. In a specific embodiment, the invention provides a method for the specific destruction of cells expressing TRID receptors on their surface (e.g., activated T-cells, cancer cells, or leukemic cells) by administering TRID. polypeptides or anti-TRID antibodies in association with toxins or cytotoxic prodrugs. In another specific embodiment, the invention provides a method for the specific destruction of cells expressing the membrane-bound form of TRID on their surface (e.g. , spleen, bone marrow, kidney and PBLs) by administering anti- TRID antibodies in association with toxins or cytotoxic prodrugs. By "toxin" is meant compounds that bind and activate endogenous cytotoxic effector systems, radioisotopes, holotoxins, modified toxins, catalytic subunits of toxins, cytotoxins (cytotoxic agents), or any molecules or enzymes not normally present in or on the surface of a cell that under defined conditions cause the cell's death. Toxins that may be used according to the methods of the invention include, but are not limited to, radioisotopes known in the art, compounds such as, for example, antibodies (or complement fixing containing portions thereof) that bind an inherent or induced endogenous cytotoxic effector system, thymidine kinase, endonuclease, RNAse, alpha toxin, ricin, abrin, Pseudomonas exotoxin A, diphtheria toxin, saporin, momordin, gelonin, pokeweed antiviral protein, alpha-sarcin and cholera toxin. "Toxin" also includes a cytostatic or cytocidal agent, a therapeutic agent or a radioactive metal ion, e.g. , alpha-emitters such as, for example, 2 l3 Bi, or other radioisotopes such as, for example, ,03 Pd, ,3 Xe, ,31 1, 68 Ge, "Co, 65 Zn, 85 Sr, 32 P, 35 S, 90 Y, l53 Sm, ,53 Gd, ,69 Yb, 51 Cr, 54 Mn, 75 Se, ' ,3 Sn, 90 Yttrium, " 7 Tin, l 86 Rhenium, l66 Holmium, and 188 Rhenium; luminescent labels, such as luminol; and fluorescent labels, such as fluorescein and rhodamine, and biotin. Techniques known in the art may be applied to label proteins (including antibodies) ofthe invention. Such techniques include, but are not limited to, the use of bifunctional conjugating agents (see, e.g. , U.S. Patent Nos. 5,756,065; 5,714,631 ; 5,696,239; 5,652,361 ; 5,505,931 ; 5,489,425; 5,435,990; 5,428,139; 5,342,604; 5,274,119; 4,994,560; and 5,808,003; the contents of each of which are hereby incoφorated by reference in its entirety). A cytotoxin or cytotoxic agent includes any agent that is detrimental to cells. Examples include paclitaxol, cytochalasin B, gramicidin D, ethidium bromide, emetine, mitomycin, etoposide, tenoposide, vincristine, vinblastine, colchicin, doxorubicin, daunorubicin, dihydroxy anthracin dione, mitoxantrone, mithramycin, actinomycin D, 1- dehydrotestosterone, glucocorticoids, procaine, tetracaine, lidocaine, propranolol, and puromycin and analogs or homologs thereof. Therapeutic agents include, but are not limited to, antimetabolites (e.g., methotrexate, 6-mercaptopurine, 6- thioguanine, cytarabine, 5-fluorouracil decarbazine), alkylating agents (e.g., mechlorethamine, thioepa chlorambucil, melphalan, carmustine (BSNU) and lomustine (CCNU), cyclothosphamide, busulfan, dibromomannitol, streptozotocin, mitomycin C, and c/s-dichlorodiamine platinum (II) (DDP) cisplatin), anthracyclines (e.g., daunorubicin (formerly daunomycin) and doxorubicin), antibiotics (e.g. , dactinomycin (formerly actinomycin), bleomycin, mithramycin, and anthramycin (AMC)), and anti-mitotic agents (e.g., vincristine and vinblastine). By "cytotoxic prodrug" is meant a non-toxic compound that is converted by an enzyme, normally present in the cell, into a cytotoxic compound. Cytotoxic prodrugs that may be used according to the methods ofthe invention include, but are not limited to, glutamyl derivatives of benzoic acid mustard alkylating agent, phosphate derivatives of etoposide or mitomycin C, cytosine arabinoside, daunorubicin, and phenoxyacetamide derivatives of doxorubicin. The invention also provides a pharmaceutical pack or kit comprising one or more containers filled with one or more ofthe ingredients ofthe pharmaceutical compositions ofthe invention. Optionally associated with such container(s) can be a notice in the form prescribed by a governmental agency regulating the manufacture, use or sale of pharmaceuticals or biological products, which notice reflects approval by the agency of manufacture, use or sale for human administration. Diagnosis and Imaging Labeled antibodies, and derivatives and analogs thereof, which specifically bind to a polypeptide of interest can be used for diagnostic puφoses to detect, diagnose, or monitor diseases and/or disorders associated with the aberrant expression and/or activity of a polypeptide of the invention. The invention provides for the detection of aberrant expression of a polypeptide of interest, comprising (a) assaying the expression of the polypeptide of interest in cells or body fluid of an individual using one or more antibodies specific to the polypeptide interest and (b) comparing the level of gene expression with a standard gene expression level, whereby an increase or decrease in the assayed polypeptide gene expression level compared to the standard expression level is indicative of aberrant expression. The invention provides a diagnostic assay for diagnosing a disorder, comprising (a) assaying the expression of the polypeptide of interest in cells or body fluid of an individual using one or more antibodies specific to the polypeptide interest and (b) comparing the level of gene expression with a standard gene expression level, whereby an increase or decrease in the assayed polypeptide gene expression level compared to the standard expression level is indicative of a particular disorder. With respect to cancer, the presence of a relatively high amount of transcript in biopsied tissue from an individual may indicate a predisposition for the development of the disease, or may provide a means for detecting the disease prior to the appearance of actual clinical symptoms. A more definitive diagnosis of this type may allow health professionals to employ preventative measures or aggressive treatment earlier thereby preventing the development or further progression ofthe cancer. Antibodies of the invention can be used to assay protein levels in a biological sample using classical immunohistological methods known to those of skill in the art (e.g. , see Jalkanen, M. et al, J. Cell. Biol 707:976-985 (1985); Jalkanen, M. et al, J. Cell. Biol 705:3087-3096 (1987)). Other antibody-based methods useful for detecting protein gene expression include immunoassays, such as the enzyme linked immunosorbent assay (ELISA) and the radioimmunoassay (RIA). Suitable antibody assay labels are known in the art and include enzyme labels, such as, glucose oxidase; radioisotopes, such as iodine ( 125 I, 12I I), carbon ( 14 C), sulfur ( 35 S), tritium ( 3 H), indium (" 2 In), and technetium ( 99 Tc); luminescent labels, such as luminol; and fluorescent labels, such as fluorescein and rhodamine. and biotin. One aspect ofthe invention is the detection and diagnosis of a disease or disorder associated with aberrant expression of a polypeptide ofthe interest in an animal, preferably a mammal and most preferably a human. In one embodiment, diagnosis comprises: a) administering (for example, parenterally, subcutaneously, or intraperitoneally) to a subject an effective amount of a labeled molecule which specifically binds to the polypeptide of interest; b) waiting for a time interval following the administering for permitting the labeled molecule to preferentially concentrate at sites in the subject where the polypeptide is expressed (and for unbound labeled molecule to be cleared to background level); c) determining background level; and d) detecting the labeled molecule in the subject, such that detection of labeled molecule above the background level indicates that the subject has a particular disease or disorder associated with aberrant expression of the polypeptide of interest. Background level can be determined by various methods including, comparing the amount of labeled molecule detected to a standard value previously determined for a particular system. It will be understood in the art that the size ofthe subject and the imaging system used will determine the quantity of imaging moiety needed to produce diagnostic images. In the case of a radioisotope moiety, for a human subject, the quantity of radioactivity injected will normally range from about 5 to 20 millicuries of 99mTc. The labeled antibody or antibody fragment will then preferentially accumulate at the location of cells which contain the specific protein. In vivo tumor imaging is described in S.W. Burchiel et al. , "Immunopharmacokinetics of Radiolabeled Antibodies and Their Fragments." (Chapter 13 in Tumor Imaging: The Radiochemical Detection of Cancer, S.W. Burchiel and B. A. Rhodes, eds., Masson Publishing Inc. ( 1982)). Depending on several variables, including the type of label used and the mode of administration, the time interval following the administration for permitting the labeled molecule to preferentially concentrate at sites in the subject and for unbound labeled molecule to be cleared to background level is 6 to 48 hours or 6 to 24 hours or 6 to 12 hours. In another embodiment the time interval following administration is 5 to 20 days or 5 to 10 days. In an embodiment, monitoring ofthe disease or disorder is carried out by repeating the method for diagnosing the disease or disease, for example, one month after initial diagnosis, six months after initial diagnosis, one year after initial diagnosis, etc. Presence of the labeled molecule can be detected in the patient using methods known in the art for in vivo scanning. These methods depend upon the type of label used. Skilled artisans will be able to determine the appropriate method for detecting a particular label. Methods and devices that may be used in the diagnostic methods ofthe invention include, but are not limited to, computed tomography (CT), whole body scan such as position emission tomography (PET), magnetic resonance imaging (MRI), and sonography. In a specific embodiment, the molecule is labeled with a radioisotope and is detected in the patient using a radiation responsive surgical instrument (Thurston et al, U.S. Patent No. 5,441,050). In another embodiment, the molecule is labeled with a fluorescent compound and is detected in the patient using a fluorescence responsive scanning instrument. In another embodiment, the molecule is labeled with a positron emitting metal and is detected in the patent using positron emission-tomography. In yet another embodiment, the molecule is labeled with a paramagnetic label and is detected in a patient using magnetic resonance imaging (MRI). Kits The present invention provides kits that can be used in the above methods. In one embodiment, a kit comprises an antibody of the invention, preferably a purified antibody, in one or more containers. In a specific embodiment, the kits ofthe present invention contain a substantially isolated polypeptide comprising an epitope which is specifically immunoreactive with an antibody included in the kit. Preferably, the kits ofthe present invention further comprise a control antibody which does not react with the polypeptide of interest. In another specific embodiment, the kits ofthe present invention contain a means for detecting the binding of an antibody to a polypeptide of interest (e.g., the antibody may be conjugated to a detectable substrate such as a fluorescent compound, an enzymatic substrate, a radioactive compound or a luminescent compound, or a second antibody which recognizes the first antibody may be conjugated to a detectable substrate). In another specific embodiment of the present invention, the kit is a diagnostic kit for use in screening serum containing antibodies specific against proliferative and/or cancerous polynucleotides and polypeptides. Such a kit may include a control antibody that does not react with the polypeptide of interest. Such a kit may include a substantially isolated polypeptide antigen comprising an epitope which is specifically immunoreactive with at least one anti-polypeptide antigen antibody. Further, such a kit includes means for detecting the binding of said antibody to the antigen (e.g.. the antibody may be conjugated to a fluorescent compound such as fluorescein or rhodamine which can be detected by flow cytometry). In specific embodiments, the kit may include a recombinantly produced or chemically synthesized polypeptide antigen. The polypeptide antigen of the kit may also be attached to a solid support. In a more specific embodiment the detecting means ofthe above-described kit includes a solid support to which said polypeptide antigen is attached. Such a kit may also include a non-attached reporter-labeled anti-human antibody. In this embodiment, binding of the antibody to the polypeptide antigen can be detected by binding of the said reporter-labeled antibody. In an additional embodiment, the invention includes a diagnostic kit for use in screening serum containing antigens ofthe polypeptide ofthe invention. The diagnostic kit includes a substantially isolated antibody specifically immunoreactive with polypeptide or polynucleotide antigens, and means for detecting the binding ofthe polynucleotide or polypeptide antigen to the antibody. In one embodiment, the antibody is attached to a solid support. In a specific embodiment, the antibody may be a monoclonal antibody. The detecting means ofthe kit may include a second, labeled monoclonal antibody. Alternatively, or in addition, the detecting means may include a labeled, competing antigen. In one diagnostic configuration, test serum is reacted with a solid phase reagent having a surface-bound antigen obtained by the methods of the present invention. After binding with specific antigen antibody to the reagent and removing unbound serum components by washing, the reagent is reacted with reporter-labeled anti-human antibody to bind reporter to the reagent in proportion to the amount of bound anti-antigen antibody on the solid support. The reagent is again washed to remove unbound labeled antibody, and the amount of reporter associated with the reagent is determined. Typically, the reporter is an enzyme which is detected by incubating the solid phase in the presence of a suitable fluorometric, luminescent or colorimetric substrate (Sigma, St. Louis, MO). The solid surface reagent in the above assay is prepared by known techniques for attaching protein material to solid support material, such as polymeric beads, dip sticks, 96-well plate or filter material. These attachment methods generally include non-specific adsoφtion ofthe protein to the support or covalent attachment of the protein, typically through a free amine group, to a chemically reactive group on the solid support, such as an activated carboxyl, hydroxyl, or aldehyde group. Alternatively, streptavidin coated plates can be used in conjunction with biotinylated antigen(s). Thus, the invention provides an assay system or kit for carrying out this diagnostic method. The kit generally includes a support with surface-bound recombinant antigens, and a reporter-labeled anti-human antibody for detecting surface-bound anti-antigen antibody. Chromosome Assays The nucleic acid molecules ofthe present invention are also valuable for chromosome identification. The sequence is specifically targeted to and can hybridize with a particular location on an individual human chromosome. Moreover, there is a current need for identifying particular sites on the chromosome. Few chromosome marking reagents based on actual sequence data (repeat polymoφhisms) are presently available for marking chromosomal location. The mapping of DNAs to chromosomes according to the present invention is an important first step in correlating those sequences with genes associated with disease. In certain preferred embodiments in this regard, the cDNAs herein disclosed are used to clone genomic DNA of a TRID protein gene. This can be accomplished using a variety of well known techniques and libraries, which generally are available commercially. The genomic DNA then is used for in situ chromosome mapping using well known techniques for this puφose. In addition, in some cases, sequences can be mapped to chromosomes by preparing PCR primers (preferably 15-25 bp) from the cDNA. Computer analysis ofthe 3' untranslated region ofthe gene is used to rapidly select primers that do not span more than one exon in the genomic DNA, thus complicating the amplification process. These primers are then used for PCR screening of somatic cell hybrids containing individual human chromosomes. Fluorescence in situ hybridization ("FISH") of a cDNA clone to a metaphase chromosomal spread can be used to provide a precise chromosomal location in one step. This technique can be used with probes from the cDNA as short as 50 or 60 bp. For a review of this technique, see Verma et al, Human Chromosomes: A Manual Of Basic Techniques, Pergamon Press, New York (1988). Once a sequence has been mapped to a precise chromosomal location, the physical position of the sequence on the chromosome can be correlated with genetic map data. Such data are found, for example, in V. McKusick, Mendelian Inheritance In Man, available on-line through Johns Hopkins University, Welch Medical Library. The relationship between genes and diseases that have been mapped to the same chromosomal region are then identified through linkage analysis (coinheritance of physically adjacent genes). Next, it is necessary to determine the differences in the cDNA or genomic sequence between affected and unaffected individuals. If a mutation is observed in some or all ofthe affected individuals but not in any normal individuals, then the mutation is likely to be the causative agent of the disease. Having generally described the invention, the same will be more readily understood by reference to the following examples, which are provided by way of illustration and are not intended as limiting. Examples Example 1: Expression and Purification ofthe "His-tagged" Extracellular form of TRID in E. coli The bacterial expression vector pQE9 (pDIO) is used for bacterial expression in this example. (QIAGEN. Inc., 9259 Eton Avenue, Chatsworth, CA, 91311). pQE9 encodes ampicillin antibiotic resistance ("Ampr") and contains a bacterial origin of replication ("ori"), an IPTG inducible promoter, a ribosome binding site ("RBS"), six codons encoding histidine residues that allow affinity purification using nickel-nitrilo-tri-acetic acid ("Ni-NTA") affinity resin sold by QIAGEN, Inc., supra, and suitable single restriction enzyme cleavage sites. These elements are arranged such that an inserted DNA fragment encoding a polypeptide expresses that polypeptide with the six His residues (i.e. , a "6 X His tag") covalently linked to the amino terminus of that polypeptide. The DNA sequence encoding the desired portion of the TRID protein comprising, or alternatively consisting of, the extracellular form of the TRID amino acid sequence is amplified from the deposited cDNA clone using PCR oligonucleotide primers which anneal to sequence encoding the amino terminal sequences of the desired portion of the TRID protein and to carboxy terminal sequences ofthe desired portion ofthe extracellular form ofthe TRID protein in the deposited cDNA. Additional nucleotides containing restriction sites to facilitate cloning in the pQE9 vector are added to the 5 ' and 3 ' primer sequences, respectively. For cloning the extracellular form ofthe TRID protein, the 5' primer has the sequence 5' CGCGGATCCACCACTGCCCGGCAGGAG 3 '(SEQ ID NO: 19) containing the underlined BamHl restriction site followed by 18 nucleotides ofthe amino terminal coding sequence ofthe extracellular TRID sequence in SEQ ID NO:2. One of ordinary skill in the art would appreciate, of course, that the point in the protein coding sequence where the 5 " primer begins and where the 3 ' primer ends may be varied to amplify a DNA segment encoding any desired portion ofthe complete TRID protein shorter or longer than the extracellular form o f the protein . The 3 ' pri mer has the s equence 5' GCGTCTAGACTAGTAATGAGAAGAGGCAGG 3' (SEQ ID NO:20) containing the underlined Xbal restriction site followed by 18 nucleotides complementary to the 3' end of cDNA encoding the extracellular domain ofthe TRID protein in SEQ ID NO:2. The amplified TRID DNA fragment and the vector pQE9 are digested with BamHl and Xbal and the digested DNAs are then ligated together. Insertion of the TRID DNA into the restricted pQE9 vector places the TRID protein coding region downstream from the IPTG-inducible promoter and in-frame with an initiating AUG and the six histidine codons. The ligation mixture is transformed into competent E. coli cells using standard procedures such as those described in Sambrook et al., Molecular Cloning: a Laboratory Manual, 2nd Ed.; Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY (1989). E. coli strain M15/rep4, containing multiple copies of the plasmid pREP4, which expresses the lac repressor and confers kanamycin resistance ("Kanr"), is used in carrying out the illustrative example described herein. This strain, which is only one of many that are suitable for expressing TRID protein, is available commercially from QIAGEN, Inc., supra. Transformants are identified by their ability to grow on LB plates in the presence of ampicillin and kanamycin. Plasmid DNA is isolated from resistant colonies and the identity ofthe cloned DNA confirmed by restriction analysis, PCR and DNA sequencing. Clones containing the desired constructs are grown overnight ("O/N") in liquid culture in LB media supplemented with both ampicillin (100 μg/ml) and kanamycin (25 μg/ml). The O/N culture is used to inoculate a large culture, at a dilution of approximately 1 :25 to 1 :250. The cells are grown to an optical density at 600 nm ("OD600") of between 0.4 and 0.6. Isopropyl-β-D- thiogalactopyranoside ("IPTG") is then added to a final concentration of 1 mM to induce transcription from the lac repressor sensitive promoter, by inactivating the lad repressor. Cells subsequently are incubated further for 3 to 4 hours. Cells then are harvested by centrifugation. The cells are then stirred for 3-4 hours at 4° C in 6M guanidine-HCl, pH 8. The cell debris is removed by centrifugation, and the supernatant containing the TRID is loaded onto a nickel-nitrilo-tri-acetic acid ("Ni-NTA") affinity resin column (available from QIAGEN, Inc., supra). Proteins with a 6 x His tag bind to the Ni-NTA resin with high affinity and can be purified in a simple one-step procedure (for details see: The QIAexpressionist, 1995, QIAGEN, Inc., supra). Briefly the supernatant is loaded onto the column in 6 M guanidine-HCl, pH 8, the column is first washed with 10 volumes of 6 M guanidine-HCl, pH 8, then washed with 10 volumes of 6 M guanidine-HCl pH 6, and finally the TRID is eluted with 6 M guanidine-HCl, pH 5. The purified protein is then renatured by dialyzing it against phosphate - buffered saline (PBS) or 50 mM Na-acetate, pH 6 buffer plus 200 mM NaCl. Alternatively, the protein can be successfully refolded while immobilized on the Ni-NTA column. The recommended conditions are as follows: renature using a linear 6M- 1 M urea gradient in 500 mM NaCl, 20% glycerol, 20 mM Tris/HCl pH 7.4, containing protease inhibitors. The renaturation should be performed over a period of 1.5 hours or more. After renaturation the proteins can be eluted by the addition of 250 mM immidazole. Immidazole is removed by a final dialyzing step against PBS or 50 mM sodium acetate pH 6 buffer plus 200 mM NaCl. The purified protein is stored at 4°C or frozen at -80° C. Example 2: Cloning and Expression of TRID in a Baculovirus Expression System In this illustrative example, the plasmid shuttle vector pA2 is used to insert the cloned DNA encoding complete protein, including its naturally associated secretory signal (leader) sequence, into a baculovirus to express the mature TRID protein, using standard methods as described in Summers et al. , A Manual of Methods for Baculovirus Vectors and Insect Cell Culture Procedures, Texas Agricultural Experimental Station Bulletin No. 1555 (1987). This expression vector contains the strong polyhedrin promoter of the Autographa calif ornica nuclear polyhedrosis virus (AcMNPV) followed by convenient restriction sites such as BamHl, Xba I and Asp718. The polyadenylation site ofthe simian virus 40 ("SV40") is used for efficient polyadenylation. For easy selection of recombinant virus, the plasmid contains the beta-galactosidase gene from E. coli under control of a weak Drosophila promoter in the same orientation, followed by the polyadenylation signal of the polyhedrin gene. The inserted genes are flanked on both sides by viral sequences for cell-mediated homologous recombination with wild-type viral DNA to generate a viable virus that express the cloned polynucleotide. Many other baculovirus vectors could be used in place ofthe vector above, such as pAc373, pVL941 and pAcIMl, as one skilled in the art would readily appreciate, as long as the construct provides appropriately located signals for transcription, translation, secretion and the like, including a signal peptide and an in-frame AUG as required. Such vectors are described, for instance, in Luckow et al., Virology 770:31-39 (1989). The cDNA sequence encoding the full length TRID protein in a deposited clone, including the AUG initiation codon and the naturally associated leader sequence shown in SEQ ID NO:2 is amplified using PCR oligonucleotide primers corresponding to the 5 ' and 3 ' sequences ofthe gene. The 5 ' primer for TRID has the sequence 5' CGCTCTAGACCGCCATCATGGCCCGGATCCCCAAG 3' (SEQ ID NO:21) containing the underlined Xbal restriction enzyme site. The described primers encode an efficient signal for initiation of translation in eukaryotic cells, as described by Kozak, M., J. Mol. Biol. 196:941-950 (1987). T h e 3 ' p r i m e r f o r T R I D h a s t h e s e q u e n c e 5' GCGTCTAGACTAGTAATGAGAAGAGGCAGG 3' (SEQ ID NO:22) containing the underlined Xbal restriction site. The amplified fragment is isolated from a 1% agarose gel using a commercially available kit ("Geneclean," BIO 101 Inc., La Jolla, Ca.). The fragment then is digested with the appropriate restriction enzyme for each ofthe primers used, as specified above, and again is purified on a 1% agarose gel. The plasmid is digested with the same restriction enzymes and optionally, can be dephosphorylated using calf intestinal phosphatase, using routine procedures known in the art. The DNA is then isolated from a 1% agarose gel using a commercially available kit ("Geneclean" BIO 101 Inc., La Jolla, Ca.). The fragment and dephosphorylated plasmid are ligated together with T4 DNA ligase. E. coli HB101 or other suitable E. coli hosts such as XL-1 Blue (Statagene Cloning Systems, La Jolla, CA) cells are transformed with the ligation mixture and spread on culture plates. Bacteria are identified that contain the plasmid with the human TNF receptor gene by digesting DNA from individual colonies using the enzymes used immediately above and then analyzing the digestion product by gel electrophoresis. The sequence ofthe cloned fragment is confirmed by DNA sequencing. This plasmid is designated herein pA2-TRID. Five μg ofthe plasmid pA2-TRID is co-transfected with 1.0 μg of a commercially available linearized baculovirus DNA ("BaculoGold™ baculovirus DNA", Pharmingen, San Diego, CA), using the lipofection method described by Feigner et al., Proc. Natl. Acad. Sci. USA 84: 7413-7417 (1987). One μg of BaculoGold™ virus DNA and 5 μg of the plasmid pA2-TNFR are mixed in a sterile well of a microtiter plate containing 50 μl of serum-free Grace's medium (Life Technologies Inc., Gaithersburg, MD). Afterwards, 10 μl Lipofectin plus 90 μl Grace's medium are added, mixed and incubated for 15 minutes at room temperature. Then the transfection mixture is added drop- wise to Sf9 insect cells (ATCC CRL 171 1) seeded in a 35 mm tissue culture plate with 1 ml Grace's medium without serum. The plate is then incubated for 5 hours at 27° C. The transfection solution is then removed from the plate and 1 ml of Grace's insect medium supplemented with 10% fetal calf serum is added. Cultivation is then continued at 27° C for four days. After four days, the supernatant is collected and a plaque assay is performed, as described by Summers and Smith, supra. An agarose gel with "Blue Gal" (Life Technologies Inc., Gaithersburg) is used , to allow easy identification and isolation of gal-expressing clones, which produce blue-stained plaques. (A detailed description of a "plaque assay" of this type can also be found in the user's guide for insect cell culture and baculovirology distributed by Life Technologies Inc., Gaithersburg, page 9-10). After appropriate incubation, blue stained plaques are picked with the tip of a micropipettor (e.g. , Eppendorf). The agar containing the recombinant viruses is then resuspended in a microcentrifuge tube containing 200 μl of Grace's medium and the suspension containing the recombinant baculovirus is used to infect Sf9 cells seeded in 35 mm dishes. Four days later, the supernatants of these culture dishes are harvested and then they are stored at 4° C. The recombinant virus is called V-TRID. To verify the expression of the V-TRID, Sf9 cells are grown in Grace's medium supplemented with 10% heat-inactivated FBS. The cells are infected with the recombinant baculovirus V-TRID at a multiplicity of infection ("MOI") of about 2. If radiolabeled proteins are desired, 6 hours later the medium is removed and is replaced with SF900 II medium minus methionine and cysteine (available from Life Technologies Inc., Rockville, MD). After 42 hours, 5 μCi of 35 S- methionine and 5 μCi 35 S-cysteine (available from Amersham) are added. The cells are further incubated for 16 hours and then are harvested by centrifugation. The proteins in the supernatant as well as the intracellular proteins are analyzed by SDS-PAGE followed by autoradiography (if radiolabeled). Microsequencing of the amino acid sequence of the amino terminus of purified protein may be used to determine the amino terminal sequence of the mature protein and thus the cleavage point and length of the secretory signal peptide. Example 3: Cloning and Expression of TRID in Mammalian Cells A typical mammalian expression vector contains the promoter element, which mediates the initiation of transcription of mRNA, the protein coding sequence, and signals required for the termination of transcription and polyadenylation ofthe transcript. Additional elements include enhancers, Kozak sequences and intervening sequences flanked by donor and acceptor sites for RNA splicing. Highly efficient transcription can be achieved with the early and late promoters from SV40, the long terminal repeats (LTRs) from Retroviruses, e.g., RSV, HTLVI, HIVI and the early promoter of the cytomegalovirus (CMV). However, cellular elements can also be used (e.g., the human actin promoter). Suitable expression vectors for use in practicing the present invention include, for example, vectors such as pSVL and pMSG (Pharmacia, Uppsala, Sweden), pRSVcat (ATCC 37152), pSV2dhfr (ATCC 37146) and pBC12MI (ATCC 67109). Mammalian host cells that could be used include: human Hela 293, H9 and Jurkat cells, mouse NIH3T3 and C127 cells, Cos 1, Cos 7 and CV1, quail QC1-3 cells, mouse L cells and Chinese hamster ovary (CHO) cells. Alternatively, the gene can be expressed in stable cell lines that contain the gene integrated into a chromosome. The co-transfection with a selectable marker such as dhfr, gpt, neomycin, hygromycin allows the identification and isolation of the transfected cells. The transfected gene can also be amplified to express large amounts ofthe encoded protein. The dihydrofolate reductase (DHFR) marker is useful to develop cell lines that carry several hundred or even several thousand copies ofthe gene of interest. Another useful selection marker is the enzyme glutamine synthase (GS) (Muφhy et al, Biochem J. 227:277-279 (1991); Bebbington et al., Bio/Technology 70:169-175 (1992)). Using these markers, the mammalian cells are grown in selective medium and the cells with the highest resistance are selected. These cell lines contain the amplified gene(s) integrated into a chromosome. Chinese hamster ovary (CHO) and NSO cells are often used for the production of proteins. The expression vectors pC 1 and pC4 contain the strong promoter (LTR) ofthe Rous Sarcoma Virus (Cullen et al, Molecular and Cellular Biology, 438- 447 (March, 1985)) plus a fragment of the CMV-enhancer (Boshart et al, Cell 47:521-530 (1985)). Multiple cloning sites, e.g., with the restriction enzyme cleavage sites BamHl, Xbal and Asp718, facilitate the cloning of the gene of interest. The vectors contain in addition the 3' intron, the polyadenylation and termination signal of the rat preproinsulin gene. Example 3(a): Cloning and Expression in COS Cells The expression plasmid, pTRID-HA, is made by cloning a cDNA encoding TRID into the expression vector pcDNAI/Amp or pcDNAIII (which can be obtained from Invitrogen, Inc.). The expression vector pcDNAI/Amp contains: (1) an E. coli origin of replication effective for propagation in E. coli and other prokaryotic cells; (2) an ampicillin resistance gene for selection of plasmid-containing prokaryotic cells; (3) an SV40 origin of replication for propagation in eukaryotic cells; (4) a CMV promoter, a polylinker, an SV40 intron; (5) several codons encoding a hemagglutinin fragment (i.e., an "HA" tag to facilitate purification) followed by a termination codon and polyadenylation signal arranged so that a cDNA can be conveniently placed under expression control ofthe CMV promoter and operably linked to the SV40 intron and the polyadenylation signal by means of restriction sites in the polylinker. The HA tag corresponds to an epitope derived from the influenza hemagglutinin protein described by Wilson et al, Cell 37: 161 (1984). The fusion ofthe HA tag to the target protein allows easy detection and recovery of the recombinant protein with an antibody that recognizes the HA epitope. pcDNAIII contains, in addition, the selectable neomycin marker. A DNA fragment encoding the TRID is cloned into the polylinker region of the vector so that recombinant protein expression is directed by the CMV promoter. The plasmid construction strategy is as follows. The TRID cDNA of the deposited clone is amplified using primers that contain convenient restriction sites, much as described above for construction of vectors for expression of a TNF receptor in E. coli. Suitable primers include the following, which are used in this example. The 5' primer for TNFR-5, containing the underlined EcoRI site, has the following sequence: 5' CGCGAATTCCGCCATCATGGCCCGGATCCCCAAG 3 ' (SEQ IDNO:23). The 3' primer, containing the underlined Xbal site, has the following sequence: 5' GCGTCTAGAGTAATGAGAAGAGGCAGG 3' (SEQ ID NO:24). The PCR amplified DNA fragment and the vector, pcDNAI/Amp, are digested with Xbal and EcoRI and then ligated. The ligation mixture is transformed into E. coli strain SURE (available from Stratagene Cloning Systems, 1 1099 North Torrey Pines Road. La Jolla. CA 92037), and the transformed culture is plated on ampicillin media plates which then are incubated to allow growth of ampicillin resistant colonies. Plasmid DNA is isolated from resistant colonies and examined by restriction analysis or other means for the presence of the fragment encoding the TRID polypeptide. For expression of recombinant TRID. COS cells are transfected with an expression vector, as described above, using DEAE-DEXTRAN, as described, for instance, in Sambrook et al, Molecular Cloning: a Laboratory Manual, Cold Spring Laboratory Press, Cold Spring Harbor, New York (1989). Cells are incubated under conditions for expression of TRID by the vector. Expression ofthe pTRID-HA fusion protein is detected by radiolabeling and immunoprecipitation, using methods described in, for example Harlow et al., Antibodies: A Laboratory Manual, 2nd Ed. ; Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York (1988). To this end, two days after transfection, the cells are labeled by incubation in media containing 35 S-cysteine for 8 hours. The cells and the media are collected, and the cells are washed and the lysed with detergent-containing RIPA buffer: 150 mM NaCl, 1 % NP-40, 0.1% SDS, 1% NP-40, 0.5% DOC, 50 mM TRIS, pH 7.5, as described by Wilson et al. cited above. Proteins are precipitated from the cell lysate and from the culture media using an HA-specific monoclonal antibody. The precipitated proteins then are analyzed by SDS-PAGE and autoradiography. An expression product ofthe expected size is seen in the cell lysate, which is not seen in negative controls. Example 3(b): Cloning and Expression in CHO Cells The vector pC4 is used for the expression of TRID polypeptides. Plasmid pC4 is a derivative ofthe plasmid pSV2-dhfr (ATCC Accession No.37146). The plasmid contains the mouse DHFR gene under control of the SV40 early promoter. Chinese hamster ovary- or other cells lacking dihydrofolate activity that are transfected with these plasmids can be selected by growing the cells in a selective medium (alpha minus MEM, Life Technologies) supplemented with the chemotherapeutic agent methotrexate. The amplification ofthe DHFR genes in cells resistant to methotrexate (MTX) has been well documented (see, e.g., Alt, F. W., Kellems, R. M., Bertino, J. R., and Schimke, R. T., 1978, J. Biol. Chem. 255: 1357-1370, Hamlin, J. L. and Ma, C. 1990, Biochem. et Biophys. Acta, 7097:107-143. Page, M. J. and Sydenham, M. A. 1991, Biotechnology 9:64-68). Cells grown in increasing concentrations of MTX develop resistance to the drug by oveφroducing the target enzyme, DHFR, as a result of amplification of the DHFR gene. If a second gene is linked to the DHFR gene, it is usually co- amplified and over-expressed. It is known in the art that this approach may be used to develop cell lines carrying more than 1 ,000 copies of the amplified gene(s). Subsequently, when the methotrexate is withdrawn, cell lines are obtained which contain the amplified gene integrated into one or more chromosome(s) ofthe host cell. Plasmid pC4 contains for expressing the gene of interest the strong promoter ofthe long terminal repeat (LTR) of the Rous Sarcoma Virus (Cullen et al., Molecular and Cellular Biology 5 :438-447 (1985) plus a fragment isolated from the enhancer ofthe immediate early gene of human cytomegalovirus (CMV) (Boshart et al, Ce/7 47:521-530 (1985)). Downstream of the promoter are the following single restriction enzyme cleavage sites that allow the integration ofthe genes: BamHl, Xba I, and Asp718. Behind these cloning sites the plasmid contains the 3 * intron and polyadenylation site of the rat preproinsulin gene. Other high efficiency promoters can also be used for the expression, e.g., the human β-actin promoter, the SV40 early or late promoters or the long terminal repeats from other retroviruses, e.g. , HIV and HTLVI. Clontech's Tet-Off and Tet-On gene expression systems and similar systems can be used to express the TRID receptor polypeptide in a regulated way in mammalian cells (Gossen, M., & Bujard, H. 1992, Proc. Natl. Acad. Sci. USA 59:5547-5551). For the polyadenylation ofthe mRNA other signals, e.g. , from the human growth hormone or globin genes can be used as well. Stable cell lines carrying a gene of interest integrated into the chromosomes can also be selected upon co-transfection with a selectable marker such as gpt, G418 or hygromycin. It is advantageous to use more than one selectable marker in the beginning, e.g., G418 plus methotrexate. The plasmid pC4 is digested with the restriction enzymes appropriate for the specific primers used to amplify TRID as outlined below and then dephosphorylated using calf intestinal phosphates by procedures known in the art. The vector is then isolated from a 1% agarose gel. The DNA sequence encoding the TRID polypeptide is amplified using PCR oligonucleotide primers corresponding to the 5' and 3' sequences of the desired portion of the gene. The 5' primer for TRID containing the underlined Xbal site, has the following sequence: 5' CGCTCTAGACCGCCATCATGGCCCGGATCCCCAAG 3' (SEQ ID NO:25). The 3' primer for TRID, containing the underlined Xbal site, has the following sequence: 5' GCGTCTAGACTAGTAATGAGAAGAGGCAGG 3' (SEQ ID NO:26). The amplified fragment is digested with the endonucleases which will cut at the engineered restriction site(s) and then purified again on a 1% agarose gel. The isolated fragment and the dephosphorylated vector are then ligated with T4 DNA ligase. E. coli HB 0 orXL-1 Blue cells are then transformed and bacteria are identified that contain the fragment inserted into plasmid pC4 using, for instance, restriction enzyme analysis. Chinese hamster ovary cells lacking an active DHFR gene are used for transfection. Five μg ofthe expression plasmid pC4 is cotransfected with 0.5 μg ofthe plasmid pSVneo using lipofectin (Feigner et al., supra). The plasmid pSV2- neo contains a dominant selectable marker, the neo gene from Tn5 encoding an enzyme that confers resistance to a group of antibiotics including G418. The cells are seeded in alpha minus MEM supplemented with 1 mg/ml G418. After 2 days, the cells are trypsinized and seeded in hybridoma cloning plates (Greiner, Germany) in alpha minus MEM supplemented with 10, 25, or 50 ng/ml of metothrexate plus 1 mg/ml G418. After about 10-14 days, single clones are trypsinized and then seeded in 6-well petri dishes or 10 ml flasks using different concentrations of methotrexate (50 nM, 100 nM, 200 nM, 400 nM, 800 nM). Clones growing at the highest concentrations of methotrexate are then transferred to new 6-well plates containing even higher concentrations of methotrexate (1 μM, 2 μM, 5 μM, 10 mM, 20 mM). The same procedure is repeated until clones are obtained which grow at a concentration of 100 - 200 μM. Expression ofthe desired gene product is analyzed, for instance, by SDS-PAGE and Western blot or by reversed phase HPLC analysis. Example 4: Protein Fusions of TRID TRID polypeptides ofthe invention are optionally fused to other proteins. These fusion proteins can be used for a variety of applications. For example, fusion of TRID polypeptides to His-tag, HA-tag, protein A, IgG domains, and maltose binding protein facilitates purification. (See EP A 394,827; Traunecker, et al, Nature 557:84-86 (1988).) Similarly, fusion to IgG- 1, IgG-3, and albumin increases the halflife time in vivo. Nuclear localization signals fused to TRID polypeptides can target the protein to a specific subcellular localization, while covalent heterodimer or homodimers can increase or decrease the activity of a fusion protein. Fusion proteins can also create chimeric molecules having more than one function. Finally, fusion proteins can increase solubility and/or stability ofthe fused protein compared to the non-fused protein. All ofthe types of fusion proteins described above can be made using techniques known in the art or by using or routinely modifying the following protocol, which outlines the fusion of a polypeptide to an IgG molecule (SEQ ID NO:27). Briefly, the human Fc portion ofthe IgG molecule can be PCR amplified, using primers that span the 5' and 3' ends of SEQ ID NO:27. These primers also preferably contain convenient restriction enzyme sites that will facilitate cloning into an expression vector, preferably a mammalian expression vector. For example, if the pC4 (Accession No.209646) expression vector is used, the human Fc portion can be ligated into the BamHl cloning site. Note that the 3' BamHl site should be destroyed. Next, the vector containing the human Fc portion is re-restricted with BamHl. linearizing the vector, and TRID polynucleotide, isolated by the PCR protocol described in Example 1 , is ligated into this BamHl site. Note that the polynucleotide is cloned without a stop codon, otherwise a fusion protein will not be produced. If the naturally occurring signal sequence is used to produce the secreted protein, pC4 does not need a second signal peptide. Alternatively, if the naturally occurring signal sequence is not used, the vector can be modified to include a heterologous signal sequence. (See, e.g., WO 96/34891.) Example 5: The Extracellular Domain of TRID Binds the Cytotoxic Ligand— TRAIL, Blocks TRAIL-induced Apoptosis As discussed above, TRAIL/ Apo2L is a cytotoxic ligand that belongs to the tumor necrosis factor (TNF) ligand family and induces rapid cell death of many transformed cell lines, but not normal tissues, despite its death domain containing receptor, DR4, being expressed on both cell types. This example identifies an antagonist decoy receptor, designated "TRAIL Receptor Without Intracellular Domain" or "TRID", that also binds TRAIL and may in part explain the resistant phenotype of normal tissues. That is. TRID, an antagonistic receptor, binds and sequesters TRAIL, but is incapable of transducing an intracellular signal. Given the similarity of the extracellular ligand binding cysteine-rich domains of TRID and DR4, the present inventors theorized that TRID would also bind TRAIL. To confirm this, the soluble extracellular ligand binding domain of TRID was expressed as a fusion to the Fc portion of human immunoglobulin (IgG). As shown in Fig. 5A, TRID-Fc specifically bound TRAIL, but not the related cytotoxic ligand TNFα. In this experiment, the Fc-extracellular domains of TRID, DR5, DR4, or TNFR1 and the corresponding ligands were prepared and binding assays performed as described in Pan etal, Science 21 '(5: 11 1 (1997). The respective Fc-fusions were precipitated with protein G-Sepharose and co- precipitated soluble ligands were detected by immunoblotting with anti-Flag (Babco) or anti-myc-HRP (BMB). The bottom panel of Fig. 5A shows the input Fc-fusions present in the binding assays. Additionally, TRID-Fc blocked the ability of TRAIL to induce apoptosis (Fig. 5B). MCF7 cells were treated with soluble TRAIL (200 ng/ml) in the presence of equal amounts of Fc-fusions or Fc alone. Six hours later, cells were fixed and examined as desribed in Pan et al., Id. The data (mean ± SD) shown in Fig. 5B are the percentage of apoptotic nuclei among total nuclei counted (n=4). Further, TRID-Fc had no effect on TNFα-induced apoptosis under conditions where TNFRl-Fc completely abolished TNFα killing (Fig 5C). MCF7 cells were treated with TNFα (40 ng/ml; Genentech. Inc.) in the presence of equal amounts of Fc-fusions or Fc alone. Nuclei were stained and examined 1 1-15 hours later. Example 6: TRID Protects Cells from TRAIL-induced Apoptosis As shown in Fig. 6, cells expressing TRID were protected from TRAIL- induced apoptosis as were cells expressing the virally encoded caspase inhibitor CrmA. Given the absence of an intracellular signalling domain, it was likely that native TRID could itself similarly attenuate TRAIL-induced cell death. This was confirmed by asking if overexpression of native TRID in TRAIL-sensitive cells (MCF7) would protect them from TRAIL-induced apoptosis. Overexpression of TRID by itself did not induce apoptosis. However, when the cells were exposed to TRAIL, cells expressing TRID were as protected from TRAIL-induced apoptosis as were cells expressing the virally encoded caspase inhibitor CrmA (Fig. 6). MCF7 cells were transfected with TRID, or CrmA expression construct or vector alone together with a b-Gal reporter construct. Twenty four hours after transfection, TRAIL was added at 50 ng/ml and 100 ng/ml. Six hours later, cells were stained with X-gal as previously described (A.M. Chinnaiy an, et al. , Cell 81, 505-12 (1995); M.P. Boldin, et al . J Biol Chem 270, 7795-8 (1995); F.C. Kischkel, et al, EMBO 14, 5579-5588 (1995)), and examined microscopically. Taken together, these findings are consistent with a guardian role for TRID that allows normal tissues to withstand the potentially deleterious effects of constitutively expressed TRAIL. The new identification of the antagonist decoy receptor TRID as a receptor for TRAIL adds further complexity to the biology of TRAIL-initiated signal transduction. Example 7: Production of an Antibody A. Hybridoma Technology The antibodies of the present invention can be prepared by a variety of methods. (See, Ausubel et al. , eds, 1994, Current Protocols in Molecular Biology, Vol. 1 , John Wiley & Sons, Inc.. New York, Chapter 2.) As one example of such methods, cells expressing TRID are administered to an animal to induce the production of sera containing polyclonal antibodies. In a preferred method, a preparation of TRID protein is prepared and purified to render it substantially free of natural contaminants. Such a preparation is then introduced into an animal in order to produce polyclonal antisera of greater specific activity. Monoclonal antibodies specific for TRID are prepared using hybridoma technology. (Kohler et al, Nature 256:495 (1975); Kohler et al, Eur. J. Immunol (5:51 1 (1976); Kohler et al. Eur. J. Immunol 6:292 (1976); Hammerling etα7. , in: Monoclonal Antibodies and T-Cell Hybridomas, Elsevier, N.Y., pp. 563-681 (1981)). In general, an animal (preferably a mouse) is immunized with a TRID polypeptide or, more preferably, with a secreted TRID polypeptide-expressing cell. Such polypeptide-expressing cells are cultured in any suitable tissue culture medium, preferably in Earle's modified Eagle's medium supplemented with 10% fetal bovine serum (inactivated at about 56°C), and supplemented with about 10 g/1 of nonessential amino acids, about 1 ,000 U/ml of penicillin, and about 100 μg/ml of streptomycin. The splenocytes of such mice are extracted and fused with a suitable myeloma cell line. Any suitable myeloma cell line may be employed in accordance with the present invention; however, it is preferable to employ the parent myeloma cell line (SP2O), available from the ATCC. After fusion, the resulting hybridoma cells are selectively maintained in HAT medium, and then cloned by limiting dilution as described by Wands et al. (Gastroenterology 50:225-232 (1981 ). The hybridoma cells obtained through such a selection are then assayed to identify clones which secrete antibodies capable of binding the TRID polypeptide. Alternatively, additional antibodies capable of binding to a TRID polypeptide can be produced in a two-step procedure using anti-idiotypic antibodies. Such a method makes use ofthe fact that antibodies are themselves antigens, and therefore, it is possible to obtain an antibody which binds to a second antibody. In accordance with this method, protein specific antibodies are used to immunize an animal, preferably a mouse. The splenocytes of such an animal are then used to produce hybridoma cells, and the hybridoma cells are screened to identify clones which produce an antibody whose ability to bind to the TRID protein-specific antibody can be blocked by TRID. Such antibodies comprise anti- idiotypic antibodies to the TRID protein-specific antibody and are used to immunize an animal to induce formation of further TRID protein-specific antibodies. For in vivo use of antibodies in humans, an antibody is "humanized" . Such antibodies can be produced using genetic constructs derived from hybridoma cells producing the monoclonal antibodies described above. Methods for producing chimeric and humanized antibodies are known in the art and are discussed infra. (See, for review, Morrison, Science 229:1202 (1985); Oi et al, BioTechniques 4:214 (1986); Cabilly et al, U.S. Patent No. 4,816,567; Taniguchi et al, EP 171496; Morrison et al, EP 173494; Neuberger et al , WO 8601533; Robinson et al, WO 8702671 ; Boulianne et al, Nature 572:643 (1984); Neuberger et al, Nature 574:268 (1985)). B. Isolation Of Antibody Fragments Directed Against Polypeptides ofthe Present Invention From A Library OfscFvs Naturally occurring V-genes isolated from human PBLs are constructed into a large library of antibody fragments which contain reactivities against polypeptides of the present invention to which the donor may or may not have been exposed (see e.g., U.S. Patent 5,885,793 incoφorated herein in its entirety by reference). Rescue ofthe library A library of scFvs is constructed from the RNA of human PBLs as described in WO92/01047. To rescue phage displaying antibody fragments, approximately 10 9 E. coli harbouring the phagemid are used to inoculate 50 ml of 2xT Y containing 1 % glucose and 100 ug/ml of ampicillin (2xTY-AMP-GLU) and grown to an O.D. of 0.8 with shaking. Five ml of this culture is used to innoculate 50 ml of 2xTY-AMP-GLU, 2xl0 8 TU of gene 3 helper phage (M13 gene III, see WO92/01047) are added and the culture incubated at 37° C for 45 minutes without shaking and then at 37° C for 45 minutes with shaking. Thexulture is centrifuged at 4000 r.p.m. for 10 minutes and the pellet resuspended in 2 liters of 2xTY containing 100 ug/ml ampicillin and 50 ug/ml kanamycin and grown overnight. Phage are prepared as described in WO92/01047. Ml 3 gene III is prepared as follows: Ml 3 gene III helper phage does not encode gene III protein, hence the phage(mid) displaying antibody fragments have a greater avidity of binding to antigen. Infectious M 13 gene III particles are made by growing the helper phage in cells harbouring a pUC 19 derivative supplying the wild type gene III protein during phage moφhogenesis. The culture is incubated for 1 hour at 37° C without shaking and then for a further hour at 37° C with shaking. Cells are pelleted (IEC-Centra 8, 4000 revs/min for 10 min), resuspended in 300 ml 2xTY broth containing 100 ug ampicillin/ml and 25 ug kanamycin/ml (2xTY-AMP-KAN) and grown overnight, shaking at 37° C. Phage particles are purified and concentrated from the culture medium by two PEG-precipitations (Sambrook et al., Molecular Cloning: a Laboratory Manual, 2nd Ed.; Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY (1989).), resuspended in 2 ml PBS and passed through a 0.45 um filter (Minisart NML; Sartorius) to give a final concentration of approximately 10 ' 3 transducing units/ml (ampicillin- resistant clones). Panning ofthe library Immunotubes (Nunc) are coated overnight in PBS with 4 ml of either 100 mg/ml or 10 mg/ml of a TRID polypeptide. Tubes are blocked with 2% Marvel- PBS for 2 hours at 37° C and then washed 3 times in PBS. Approximately 10 13 TU of phage are applied to the tube and incubated for 30 minutes at room temperature tumbling on an over and under turntable and then left to stand for another 1.5 hours. Tubes are washed 10 times with PBS 0.1 % Tween-20 and 10 times with PBS. Phage are eluted by adding 1 ml of 100 mM triethylamine and rotating 15 minutes on an under and over turntable after which the solution is immediately neutralized with 0.5 ml of 1.0M Tris-HCl, pH 7.4. Phage are then used to infect 10 ml of mid-log E. coli TGI by incubating eluted phage with bacteria for 30 minutes at 37° C. The E. coli are then plated on TYE plates containing 1 % glucose and 100 ug/ml ampicillin. The resulting bacterial library is then rescued with gene III helper phage as described above to prepare phage for a subsequent round of selection. This process is then repeated for a total of 4 rounds of affinity purification with tube- washing increased to 20 times with PBS, 0.1% Tween-20 and 20 times with PBS for rounds 3 and 4. Characterization of binders Eluted phage from the 3rd and 4th rounds of selection are used to infect E. coli HB 2151 and soluble scFv is produced (Marks, et al., 1991) from single colonies for assay. ELISAs are performed with microtitre plates coated with either 10 pg/ml ofthe polypeptide ofthe present invention in 50 mM bicarbonate pH 9.6. Clones positive in ELISA are further characterized by PCR fingeφrinting (see e.g., WO92/01047) and then by sequencing. Example 8: Tissue distribution of TRID mRNA expression Northern blot analysis was carried out to examineTRID gene expression in human tissues, using methods described by, among others, Sambrook et al., Molecular Cloning: a Laboratory Manual, 2nd Ed.; Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY (1989).. A cDNA probe containing the entire nucleotide sequence ofthe TRID protein (SEQ ID NO: 1) was labeled with 3 P using the reJ. ' prime™ DNA labeling system (Amersham Life Science), according to manufacturer's instructions. After labeling, the probe was purified using a CHROMA SPIN- 100™ column (Clontech Laboratories. Inc.), according to manufacturer's protocol number PT1200-1. The purified labeled probe was then used to examine various human tissues for TRID mRNA. Multiple Tissue Northern (MTN) blots containing various human tissues (H) or human immune system tissues (IM) were obtained from Clontech (Palo Alto, CA) and examined with labeled probe using ExpressHyb™ hybridization solution (Clontech) according to manufacturer's protocol number PT 1 190-1. Following hybridization and washing, the blots were mounted and exposed to film at -70 °C overnight. The films were developed according to standard procedures. Expression of TRID was detected in many normal human tissues, such as heart, brain, placenta, lung, liver, kidney, pancreas, spleen, thymus, peripheral blood leukocytes (PBLs), lymph node, bone marrow, and fetal liver, but not in most transformed cancer cell lines. Expression of TRID was also assessed by Northern blot in the following cancer cell lines, HL60 (promyelocytic leukemia), Hela cell S3, K562 (chronic myelogeneous leukemia), MOLT4 (lymphoblast leukemia), Raji (Burkitt's lymphoma), SW480 (colorectal adenocarcinoma), A549 (lung carcinoma), and G361 (melanoma), and was detected in only SW480 and Hela cell S3. Example 9: Method of Determining Alterations in the TRID Gene RNA is isolated from entire families or individual patients presenting with a phenotype of interest (such as a disease). cDNA is then generated from these RNA samples using protocols known in the art. (See Sambrook et al., Molecular Cloning: a Laboratory Manual, 2nd Ed.; Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY (1989).) The cDNA is then used as a template for PCR, employing primers surrounding regions of interest in SEQ ID NOT . Suggested PCR conditions consist of 35 cycles at 95° C for 30 seconds; 60-120 seconds at 52-58° C; and 60-120 seconds at 70° C, using buffer solutions described in Sidransky, D., et al, Science 252:106 (1991). PCR products are then sequenced using primers labeled at their 5' end with T4 polynucleotide kinase, employing SequiTherm Polymerase. (Epicentre Technologies). The intron-exon borders of selected exons of TRID are also determined and genomic PCR products analyzed to confirm the results. PCR products harboring suspected mutations in TRID is then cloned and sequenced to validate the results ofthe direct sequencing. PCR products of TRID are cloned into T-tailed vectors as described in Holton, T.A. and Graham, M.W., Nucleic Acids Research, 79: 1156 (Ϊ991) and sequenced with T7 polymerase (United States Biochemical). Affected individuals are identified by mutations in TRID not present in unaffected individuals. Genomic rearrangements are also observed as a method of determining alterations in the TRID gene. Genomic clones isolated using techniques known in the art are nick-translated with digoxigenindeoxy-uridine 5'-triphosphate (Boehringer Manheim), and FISH performed as described in Johnson, C. et al, Methods Cell Biol. 55:73-99 (1991). Hybridization with the labeled probe is carried out using a vast excess of human cot-1 DNA for specific hybridization to the TRID genomic locus. Chromosomes are counterstained with 4,6-diamino-2-phenylidole and propidium iodide, producing a combination of C- and R-bands. Aligned images for precise mapping are obtained using a triple-band filter set (Chroma Technology, Brattleboro, VT) in combination with a cooled charge-coupled device camera (Photometries, Tucson, AZ) and variable excitation wavelength filters. (Johnson, Cv. et al, Genet. Anal Tech. Appl, 8:15 (1991).) Image collection, analysis and chromosomal fractional length measurements are performed using the ISee Graphical Program System. (Inovision Corporation. Durham, NC.) Chromosome alterations of the genomic region of TRID (hybridized by the probe) are identified as insertions, deletions, and translocations. These TRID alterations are used as a diagnostic marker for an associated disease. Example 10: Method of Detecting Abnormal Levels of TRID in a Biological Sample TRID polypeptides can be detected in a biological sample, and if an increased or decreased level of TRID is detected, this polypeptide is a marker for a particular phenotype. Methods of detection are numerous, and thus, it is understood that one skilled in the art can modify the following assay to fit their particular needs. For example, antibody-sandwich ELISAs are used to detect TRID in a sample, preferably a biological sample. Wells of a microtiter plate are coated with specific antibodies to TRID, at a final concentration of 0.2 to 10 ug ml. The antibodies are either monoclonal or polyclonal and are produced using technique known in the art. The wells are blocked so that non-specific binding of TRID to the well is reduced. The coated wells are then incubated for > 2 hours at RT with a sample containing TRID. Preferably, serial dilutions of the sample should be used to validate results. The plates are then washed three times with deionized or distilled water to remove unbounded TRID. Next, 50 ul of specific antibody-alkaline phosphatase conjugate, at a concentration of 25-400 ng, is added and incubated for 2 hours at room temperature. The plates are again washed three times with deionized or distilled water to remove unbounded conjugate. 75 ul of 4-methylumbelliferyl phosphate (MUP) or p-nitrophenyl phosphate (NPP) substrate solution is then added to each well and incubated 1 hour at room temperature to allow cleavage of the substrate and flourescence. The flourescence is measured by a microtiter plate reader. A standard curve is preparded using the experimental results from serial dilutions of a control sample with the sample concentration plotted on the X-axis (log scale) and fluorescence or absorbance on the Y-axis (linear scale). The TRID polypeptide concentration in a sample is then interpolated using the standard curve based on the measured flourescence of that sample. Example 11: Method of Effecting Decreased Levels of TRID The present invention relates to a method for treating an individual in need of a decreased level of TRID biological activity in the body comprising, administering to such an individual a composition comprising a therapeutically effective amount of TRID antagonist. Preferred antagonists for use in the present invention are TRID-specific antibodies. Additionally, antisense technology is used to inhibit production of TRID. This technology is one example of a method of decreasing levels of TRID polypeptide, preferably a soluble and/or secreted form, due to a variety of etiologies, such as cancer. For example, a patient diagnosed with abnormally increased levels of TRID is administered intravenously antisense polynucleotides at 0.5, 1.0, 1.5, 2.0 and 3.0 mg/kg day for 21 days. This treatment is repeated after a 7-day rest period if the is determined to be well tolerated. Example 12: Method of Effecting Increased Levels of TRID The present invention also relates to a method for treating an individual in need of an increased level of TRID biological activity in the body comprising administering to such an individual a composition comprising a therapeutically effective amount of TRID or an agonist thereof. Moreover, it will be appreciated that conditions caused by a decrease in the standard or normal expression level of TRID in an individual can be treated by administering TRID, preferably in a soluble and/or secreted form. Thus, the invention also provides a method of treatment of an individual in need of an increased level of TRID polypeptide comprising administering to such an individual a pharmaceutical composition comprising an amount of TRID to increase the biological activity level of TRID in such an individual. For example, a patient with decreased levels of TRID polypeptide receives a daily dose 0.1 - 100 ug/kg ofthe polypeptide for six consecutive days. Preferably, the polypeptide is in a soluble and/or secreted form. Example 13: Method of Treatment Using Gene Therapy - Ex Vivo One method of gene therapy transplants fibroblasts, which are capable of expressing soluble and/or mature TRID polypeptides, onto a patient. Generally, fibroblasts are obtained from a subject by skin biopsy. The resulting tissue is placed in tissue-culture medium and separated into small pieces. Small chunks of the tissue are placed on a wet surface of a tissue culture flask, approximately ten pieces are placed in each flask. The flask is turned upside down, close tight and left at room temperature over night. After 24 hours at room temperature, the flask is inverted and the chunks of tissue remain fixed to the bottom ofthe flask and fresh media (e.g., Ham's F12 media, with 10% FBS, penicillin and streptomycin) is added. The flasks are then incubated at 37 ° C for approximately one week. At this time, fresh media is added and subsequently changed every several days. After an additional two weeks in culture, a monolayer of fibroblasts emerge. The monolayer is trypsinized and scaled into larger flasks. pMV-7 (Kirschmeier, P.T. et al, DNA, 7:219-25 (1988)), flanked by the long terminal repeats of the Moloney murine sarcoma virus, is digested with EcoRI and Hindlll and subsequently treated with calf intestinal phosphatase. The linear vector is fractionated on agarose gel and purified, using glass beads. The cDNA encoding TRID can be amplified using PCR primers which correspond to the 5' and 3' end encoding sequences respectively. Preferably, the 5' primer contains an EcoRI site and the 3' primer includes a Hindlll site. Equal quantities ofthe Moloney murine sarcoma virus linear backbone and the amplified EcoRI and Hindlll fragment are added together, in the presence of T4 DNA ligase. The resulting mixture is maintained under conditions appropriate for ligation of the two fragments. The ligation mixture is then used to transform E. coli HB101, which are then plated onto agar containing kanamycin for the puφose of confirming that the vector contains properly inserted TRID. The amphotropic pA317 or GP+aml 2 packaging cells are grown in tissue culture to confluent density in Dulbecco's Modified Eagles Medium (DMEM) with 10% calf serum (CS), penicillin and streptomycin. The MSV vector containing the TRID gene is then added to the media and the packaging cells transduced with the vector. The packaging cells now produce infectious viral particles containing the TRID gene (the packaging cells are now referred to as producer cells). Fresh media is added to the transduced producer cells, and subsequently, the media is harvested from a 10 cm plate of confluent producer cells. The spent media, containing the infectious viral particles, is filtered through a millipore filter to remove detached producer cells and this media is then used to infect fibroblast cells. Media is removed from a sub-confluent plate of fibroblasts and quickly replaced with the media from the producer cells. This media is removed and replaced with fresh media. If the titer of virus is high, then virtually all fibroblasts will be infected and no selection is required. If the titer is very low, then it is necessary to use a retroviral vector that has a selectable marker, such as neo or his. Once the fibroblasts have been efficiently infected, the fibroblasts are analyzed to determine whether TRID protein is produced. The engineered fibroblasts are then transplanted onto the host, either alone or after having been grown to confluence on cytodex 3 microcarrier beads. Example 14: Method of Treatment Using Gene Therapy - in vivo Another aspect of the present invention is using in vivo gene therapy methods to treat disorders, diseases and conditions. The gene therapy method relates to the introduction of naked nucleic acid (DNA, RNA, and antisense DNA or RNA) TRID sequences into an animal to increase or decrease the expression ofthe TRID polypeptide. The TRID polynucleotide may be operatively linked to a promoter or any other genetic elements necessary for the expression of the TRID polypeptide by the target tissue. Such gene therapy and delivery techniques and methods are known in the art, see, for example, WO90/11092, WO98/1 1779; U.S. PatentNO. 5693622, 5705151 , 5580859; Tabata H. et al, Cardiovasc. Res. 35:410-419 (1997); Chao J. et al, Pharmacol Res. 55:517-522 (1997); Wolff J.A. Neuromuscul Disord. 7:314-318 (1997); Schwartz B. et al, Gene Ther. 5:405-41 1 (1996); Tsurumi Y. et al, Circulation 94:3281-3290 (1996) (incoφorated herein by reference). The TRID polynucleotide constructs may be delivered by any method that delivers injectable materials to the cells of an animal, such as, injection into the interstitial space of tissues (heart, muscle, skin, lung, liver, intestine and the like). The TRID polynucleotide constructs can be delivered in a pharmaceutically acceptable liquid or aqueous carrier. The term "naked" polynucleotide, DNA or RNA, refers to sequences that are free from any delivery vehicle that acts to assist, promote, or facilitate entry into the cell, including viral sequences, viral particles, liposome formulations, lipofectin or precipitating agents and the like. However, the TRID polynucleotides may also be delivered in liposome formulations (such as those taught in Feigner P.L., et al. Ann. NY Acad. Sci. 772:126-139 (1995), and Abdallah B., et al. Biol. Cell 85(1): 1-7 (1995)) which can be prepared by methods well known to those skilled in the art. The TRID polynucleotide vector constructs used in the gene therapy method are preferably constructs that will not integrate into the host genome nor will they contain sequences that allow for replication. Any strong promoter known to those skilled in the art can be used for driving the expression of DNA. Unlike other gene therapies techniques, one major advantage of introducing naked nucleic acid sequences into target cells is the transitory nature of the polynucleotide synthesis in the cells. Studies have shown that non-replicating DNA sequences can be introduced into cells to provide production ofthe desired polypeptide for periods of up to six months. The TRID polynucleotide construct can be delivered to the interstitial space of tissues within the an animal, including of muscle, skin, brain, lung, liver, spleen, bone marrow, thymus, heart, lymph, blood, bone, cartilage, pancreas, kidney, gall bladder, stomach, intestine, testis, ovary, uterus, rectum, nervous system, eye, gland, and connective tissue. Interstitial space of the tissues comprises the intercellular fluid, mucopolysaccharide matrix among the reticular fibers of organ tissues, elastic fibers in the walls of vessels or chambers, collagen fibers of fibrous tissues, or that same matrix within connective tissue ensheathing muscle cells or in the lacunae of bone. It is similarly the space occupied by the plasma ofthe circulation and the lymph fluid ofthe lymphatic channels. Delivery to the interstitial space of muscle tissue is preferred for the reasons discussed below. They may be conveniently delivered by injection into the tissues comprising these cells. They are preferably delivered to and expressed in persistent, non-dividing cells which are differentiated, although delivery and expression may be achieved in non-differentiated or less completely differentiated cells, such as, for example, stem cells of blood or skin fibroblasts. In vivo muscle cells are particularly competent in their ability to take up and express polynucleotides. For the naked TRID polynucleotide injection, an effective dosage amount of DNA or RNA will be in the range of from about 0.05 g/kg body weight to about 50 mg/kg body weight. Preferably the dosage will be from about 0.005 mg/kg to about 20 mg/kg and more preferably from about 0.05 mg/kg to about 5 mg/kg. Of course, as the artisan of ordinary skill will appreciate, this dosage will vary according to the tissue site of injection. The appropriate and effective dosage of nucleic acid sequence can readily be determined by those of ordinary skill in the art and may depend on the condition being treated and the route of administration. The preferred route of administration is by the parenteral route of injection into the interstitial space of tissues. However, other parenteral routes may also be used, such as, inhalation of an aerosol formulation particularly for delivery to lungs or bronchial tissues, throat or mucous membranes of the nose. In addition, naked TRID polynucleotide constructs can be delivered to arteries during angioplasty by the catheter used in the procedure. The dose response effects of injected TRID polynucleotide in muscle in vivo is determined as follows. Suitable TRID template DNA for production of mRNA coding for TRID polypeptide is prepared in accordance with a standard recombinant DNA methodology. The template DNA, which may be either circular or linear, is either used as naked DNA or complexed with liposomes. The quadriceps muscles of mice are then injected with various amounts ofthe template DNA. Five to six week old female and male Balb/C mice are anesthetized by intraperitoneal injection with 0.3 ml of 2.5% Avertin. A 1.5 cm incision is made on the anterior thigh, and the quadriceps muscle is directly visualized. The TRID template DNA is injected in 0.1 ml of carrier in a 1 cc syringe through a 27 gauge needle over one minute, approximately 0.5 cm from the distal insertion site ofthe muscle into the knee and about 0.2 cm deep. A suture is placed over the injection site for future localization, and the skin is closed with stainless steel clips. After an appropriate incubation time (e.g., 7 days) muscle extracts are prepared by excising the entire quadriceps. Every fifth 15 um cross-section ofthe individual quadriceps muscles is histochemically stained for TRID protein expression. A time course for TRID protein expression may be done in a similar fashion except that quadriceps from different mice are harvested at different times. Persistence of TRID DNA in muscle following injection may be determined by Southern blot analysis after preparing total cellular DNA and HIRT supernatants from injected and control mice. The results ofthe above experimentation in mice can be use to extrapolate proper dosages and other treatment parameters in humans and other animals using TRID naked DNA. Example 15: Assays to detect stimulation or inhibition ofB cell proliferation and differentiation Generation of functional humoral immune responses requires both soluble and cognate signaling between B-lineage cells and their microenvironment. Signals may impart a positive stimulus that allows a B-lineage cell to continue its programmed development, or a negative stimulus that instructs the cell to arrest its current developmental pathway. To date, numerous stimulatory and inhibitory signals have been found to influence B cell responsiveness including IL-2, IL-4, IL5, IL6, IL-7, IL10, IL-13, IL14 and IL15. Interestingly, these signals are by themselves weak effectors but can, in combination with various co-stimulatory proteins, induce activation, proliferation, differentiation, homing, tolerance and death among B cell populations. One of the best studied classes of B-cell co- stimulatory proteins is the TNF-superfamily . Within this family CD40, CD27, and CD30 along with their respective ligands CD 154, CD70, and CD 153 have been found to regulate a variety of immune responses. Assays which allow for the detection and/or observation ofthe proliferation and differentiation of these B-cell populations and their precursors are valuable tools in determining the effects various proteins may have on these B-cell populations in terms of proliferation and differentiation. Listed below are two assays designed to allow for the detection of the differentiation, proliferation, or inhibition of B-cell populations and their precursors. Experimental Procedure: In vitro assay- Purified TRID protein, or truncated forms thereof, is assessed for its ability to induce activation, proliferation, differentiation or inhibition and/or death in B-cell populations and their precursors. The activity of TRID protein on purified human tonsillar B cells, measured qualitatively over the dose range from 0.1 to 10,000 ng/mL. is assessed in a standard B-lymphocyte co- stimulation assay in which purified tonsillar B cells are cultured in the presence of either formalin-fixed Staphylococcus aureus Cowan I (SAC) or immobilized anti- human IgM antibody as the priming agent. Second signals such as IL-2 and IL- 15 synergize with SAC and IgM crosslinking to elicit B cell proliferation as measured by tritiated-thymidine incoφoration. Novel synergizing agents can be readily identified using this assay. The assay involves isolating human tonsillar B cells by magnetic bead (MACS) depletion of CD3-positive cells. The resulting cell population is greater than 95% B cells as assessed by expression of CD45R(B220). Various dilutions of each sample are placed into individual wells of a 96-well plate to which are added 10 5 B-cells suspended in culture medium (RPMI 1640 containing 10% FBS, 5 X 10 "5 M βME, lOOU/ml penicillin, lOug/ml streptomycin, and 10 "5 dilution of SAC) in a total volume of 150ul. Proliferation or inhibition is quantitated by a 20h pulse (luCi/well) with 3 H-thymidine (6.1 Ci/mM) beginning 72h post factor addition. The positive and negative controls are IL2 and medium respectively. In vivo assay- BALB/c mice are injected (i.p.) twice per day with buffer only, or 2 mg/Kg of TRID protein, or truncated forms thereof. Mice receive this treatment for 4 consecutive days, at which time they are sacrificed and various tissues and serum collected for analyses. Comparison of H&E sections from normal and TRID protein-treated spleens identify the results of the activity of TRID protein on spleen cells, such as the diffusion of peri-arterial lymphatic sheaths, and/or significant increases in the nucleated cellularity of the red pulp regions, which may indicate the activation ofthe differentiation and proliferation of B-cell populations. Immunohistochemical studies using a B cell marker, anti- CD45R(B220), are used to determine whether any physiological changes to splenic cells, such as splenic disorganization, are due to increased B-cell representation within loosely defined B-cell zones that infiltrate established T-cell regions. Flow cytometric analyses ofthe spleens from TRID protein-treated mice is used to indicate whether TRID protein specifically increases the proportion of ThB+, CD45R(B220)dull B cells over that which is observed in control mice. Likewise, a predicted consequence of increased mature B-cell representation in vivo is a relative increase in serum Ig titers. Accordingly, serum IgM and IgA levels are compared between buffer and TRID protein-treated mice. The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g., gene therapy), agonists, and/or antagonists of TRID. Example 18: T Cell Proliferation Assay A CD3-induced proliferation assay is performed on PBMCs and is measured by the uptake of 3 H-thymidine. The assay is performed as follows. Ninety-six well plates are coated with 100 μl/well of mAb to CD3 (HIT3a, Pharmingen) or isotype-matched control mAb (B33.1 ) overnight at 4°C ( 1 μg/ml in .05M bicarbonate buffer, pH 9.5), then washed three times with PBS. PBMC are isolated by Ficoll-Hypaque gradient centrifugation from human peripheral blood and added to quadruplicate wells (5 x 10 4 /well) of mAb coated plates in RPMI containing 10% fetal bovine serum, about 1 ,000 U/ml of penicillin, and about 100 μg/ml of streptomycin in the presence of varying concentrations of TRID protein (total volume 200 μl). Relevant protein buffer and medium alone are controls. After 48 hr. culture at 37°C. plates are spun for 2 min. at 1000 φm and 100 μl of supernatant is removed and stored -20°C for measurement of IL-2 (or other cytokines) if effect on proliferation is observed. Wells are supplemented with 100 μl of medium containing 0.5 μCi of 3 H-thymidine and cultured at 37°C for 18-24 hr. Wells are harvested and incoφoration of 3 H-thymidine used as a measure of proliferation. Anti-CD3 alone is the positive control for proliferation. IL-2 (100 U/ml) is also used as a control which enhances proliferation. Control antibody which does not induce proliferation of T cells is used as the negative controls for the effects of TRID proteins. The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g., gene therapy), agonists, and/or antagonists of TRID. Example 17: Effect of TRID on the Expression ofMHC Class II, Costimulatory and Adhesion Molecules and Cell Differentiation of Monocytes and Monocyte-Derived Human Dendritic Cells Dendritic cells are generated by the expansion of proliferating precursors found in the peripheral blood: adherent PBMC or elutriated monocytic fractions are cultured for 7-10 days with GM-CSF (50 ng/ml) and IL-4 (20 ng/ml). These dendritic cells have the characteristic phenotype of immature cells (expression of CD1 , CD80, CD86, CD40 and MHC class II antigens). Treatment with activating factors, such as TNF-α, causes a rapid change in surface phenotype (increased expression of MHC class I and II, costimulatory and adhesion molecules, downregulation of FCγRII, upregulation of CD83). These changes correlate with increased antigen-presenting capacity and with functional maturation of the dendritic cells. FACS analysis of surface antigens is performed as follows. Cells are treated 1-3 days with increasing concentrations of TRID or LPS (positive control), washed with PBS containing 1% BSA and 0.02 mM sodium azide, and then incubated with 1 :20 dilution of appropriate FITC- or PE-labeled monoclonal antibodies for 30 minutes at 4°C. After an additional wash, the labeled cells are analyzed by flow cytometry on a FACScan (Becton Dickinson). Effect on the production of cytokines Cytokines generated by dendritic cells, in particular IL-12, are important in the initiation of T-cell dependent immune responses. IL- 12 strongly influences the development of Thl helper T-cell immune response, and induces cytotoxic T and NK cell function. An ELISA is used to measure the IL-12 release as follows. Dendritic cells ( 10 ml) are treated with increasing concentrations of TRID for 24 hours. LPS (100 ng/ml) is added to the cell culture as positive control. Supernatants from the cell cultures are then collected and analyzed for IL-12 content using commercial ELISA kit (e.g. , R & D Systems (Minneapolis, MN)). The standard protocols provided with the kits are used. Effect on the expression of MHC Class II, costimulatory and adhesion molecules. Three major families of cell surface antigens can be identified on monocytes: adhesion molecules, molecules involved in antigen presentation, and Fc receptor. Modulation of the expression of MHC class II antigens and other costimulatory molecules, such as B7 and ICAM-1, may result in changes in the antigen presenting capacity of monocytes and ability to induce T cell activation. Increase expression of Fc receptors may correlate with improved monocyte cytotoxic activity, cytokine release and phagocytosis. FACS analysis is used to examine the surface antigens as follows. Monocytes are treated 1-5 days with increasing concentrations of TRID or LPS (positive control), washed with PBS containing 1% BSA and 0.02 mM sodium azide, and then incubated with 1 :20 dilution of appropriate FITC- or PE-labeled monoclonal antibodies for 30 minutes at 4°C. After an additional wash, the labeled cells are analyzed by flow cytometry on a FACScan (Becton Dickinson). Monocyte activation and/or increased survival. Assays for molecules that activate (or alternatively, inactivate) monocytes and/or increase monocyte survival (or alternatively, decrease monocyte survival) are known in the art and may routinely be applied to determine whether a molecule of the invention functions as an inhibitor or activator of monocytes. TRID, agonists, or antagonists of TRID can be screened using the three assays described below. For each of these assays, Peripheral blood mononuclear cells (PBMC) are purified from single donor leukopacks (American Red Cross, Baltimore, MD) by centrifugation through a Histopaque gradient (Sigma). Monocytes are isolated from PBMC by counterflow centrifugal elutriation. 1. Monocyte Survival Assay. Human peripheral blood monocytes progressively lose viability when cultured in absence of serum or other stimuli. Their death results from internally regulated process (apoptosis). Addition to the culture of activating factors, such as TNF-alpha dramatically improves cell survival and prevents DNA fragmentation. Propidium iodide (PI) staining is used to measure apoptosis as follows. Monocytes are cultured for 48 hours in polypropylene tubes in serum-free medium (positive control), in the presence of 100 ng/ml TNF-alpha (negative control), and in the presence of varying concentrations of the compound to be tested. Cells are suspended at a concentration of 2 x 10 6 /ml in PBS containing PI at a final concentration of 5 μg/ml, and then incubated at room temperature for 5 minutes before FAC Scan analysis. PI uptake has been demonstrated to correlate with DNA fragmentation in this experimental paradigm. Effect on cytokine release. An important function of monocytes/macrophages is their regulatory activity on other cellular populations ofthe immune system through the release of cytokines after stimulation. An ELISA to measure cytokine release is performed as follows. Human monocytes are incubated at a density of 5x10 5 cells/ml with increasing concentrations of TRID and under the same conditions, but in the absence of TRID. For IL-12 production, the cells are primed overnight with IFN- γ (100 U/ml) in presence of TRID. LPS (10 ng/ml) is then added. Conditioned media are collected after 24h and kept frozen until use. Measurement of TNF-α, IL- 10, MCP- 1 and IL-8 is then performed using a commercially available ELISA kit (e.g., R & D Systems (Minneapolis, MN)) applying the standard protocols provided with the kit. 3. Oxidative burst. Purified monocytes are plated in 96-well plate at 2-lxl 0 5 cell/well. Increasing concentrations of TRID are added to the wells in a total volume of 0.2 ml culture medium (RPMI 1640 + 10% FCS, glutamine and antibiotics). After 3 days incubation, the plates are centrifuged and the medium is removed from the wells. To the macrophage monolayers, 0.2 ml per well of phenol red solution ( 140 mM NaCl, 10 mM potassium phosphate buffer pH 7.0, 5.5 mM dextrose, 0.56 mM phenol red and 19 U/ml of HRPO) is added, together with the stimulant (200 nM PMA). The plates are incubated at 37°C for 2 hours and the reaction is stopped by adding 20 μl IN NaOH per well. The absorbance is read at 610 nm. To calculate the amount of H 2 O 2 produced by the macrophages, a standard curve of a H 2 O 2 solution of known molarity is performed for each experiment. The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g., gene therapy), agonists, and/or antagonists of TRID. Example 18: The Effect of TRID on the Growth of Vascular Endothelial Cells On day 1 , human umbilical vein endothelial cells (HUVEC) are seeded at 2-5x10 4 cells/35 mm dish density in Ml 99 medium containing 4% fetal bovine serum (FBS), 16 units/ml heparin, and 50 units/ml endothelial cell growth supplements (ECGS, Biotechnique, Inc.). On day 2, the medium is replaced with Ml 99 containing 10% FBS, 8 units/ml heparin. TRID protein of SEQ ID NO. 2, and positive controls, such as VEGF and basic FGF (bFGF) are added, at varying concentrations. On days 4 and 6, the medium is replaced. On day 8, cell number is determined with a Coulter Counter. An increase in the number of HUVEC cells indicates that TRID may proliferate vascular endothelial cells. The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g., gene therapy), agonists, and/or antagonists of TRID. Example 19: Stimulatory Effect of TRID on the Proliferation of Vascular Endothelial Cells For evaluation of mitogenic activity of growth factors, the colorimetric MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4- sulfophenyl)2H-tetrazolium) assay with the electron coupling reagent PMS (phenazine methosulfate) was performed (CellTiter 96 AQ, Promega). Cells are seeded in a 96-well plate (5,000 cells/well) in 0.1 ml serum-supplemented medium and are allowed to attach overnight. After serum-starvation for 12 hours in 0.5% FBS, conditions (bFGF, VEGF, 65 or TRID in 0.5% FBS) with or without Heparin (8 U/ml) are added to wells for 48 hours. 20 mg of MTS/PMS mixture (1 :0.05) are added per well and allowed to incubate for 1 hour at 37°C before measuring the absorbance at 490 nm in an ELISA plate reader. Background absorbance from control wells (some media, no cells) is subtracted, and seven wells are performed in parallel for each condition. See, Leak et al. In vitro Cell. Dev. Biol. 30A:512- 518 (1994). The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g., gene therapy), agonists, and/or antagonists of TRID. Example 20: Inhibition of PDGF-induced Vascular Smooth Muscle Cell Proliferation Stimulatory Effect HAoSMC proliferation can be measured, for example, by BrdUrd incoφoration. Briefly, subconfluent, quiescent cells grown on the 4-chamber slides are transfected with CRP or FITC-labeled AT2-3LP. Then, the cells are pulsed with 10% calf serum and 6 mg/ml BrdUrd. After 24 h. immunocytochemistry is performed by using BrdUrd Staining Kit (Zymed Laboratories). In brief, the cells are incubated with the biotinylated mouse anti- BrdUrd antibody at 4 °C for 2 h after exposing to denaturing solution and then with the streptavidin-peroxidase and diaminobenzidine. After counterstaining with hematoxylin, the cells are mounted for microscopic examination, and the BrdUrd-positive cells are counted. The BrdUrd index is calculated as a percent of the BrdUrd-positive cells to the total cell number. In addition, the simultaneous detection of the BrdUrd staining (nucleus) and the FITC uptake (cytoplasm) is performed for individual cells by the concomitant use of bright field illumination and dark field-UV fluorescent illumination. See, Hayashida et al, J. Biol. Chem. 6;271(3 '6) '.21985-21992 (1996). The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g., gene therapy), agonists, and/or antagonists of TRID. Example 21: Stimulation of Endothelial Migration This example will be used to explore the possibility that TRID may stimulate lymphatic endothelial cell migration. Endothelial cell migration assays are performed using a 48 well microchemotaxis chamber (Neuroprobe Inc., Cabin John, MD; Falk, W., Goodwin, R. H. J., and Leonard, E. J. "A 48 well micro chemotaxis assembly for rapid and accurate measurement of leukocyte migration." J. Immunological Methods 1980;55:239-247). Polyvinylpyrrolidone-free polycarbonate filters with a pore size of 8 um (Nucleopore Corp. Cambridge, MA) are coated with 0.1% gelatin for at least 6 hours at room temperature and dried under sterile air. Test substances are diluted to appropriate concentrations in Ml 99 supplemented with 0.25% bovine serum albumin (BSA), and 25 ul ofthe final dilution is placed in the lower chamber ofthe modified Boyden apparatus. Subconfluent, early passage (2-6) HUVEC or BMEC cultures are washed and trypsinized for the minimum time required to achieve cell detachment. After placing the filter between lower and upper chamber, 2.5 x 10 5 cells suspended in 50 ul Ml 99 containing 1% FBS are seeded in the upper compartment. The apparatus is then incubated for 5 hours at 37°C in a humidified chamber with 5% CO2 to allow cell migration. After the incubation period, the filter is removed and the upper side of the filter with the non-migrated cells is scraped with a rubber policeman. The filters are fixed with methanol and stained with a Giemsa solution (Diff-Quick, Baxter, McGraw Park, IL). Migration is quantified by counting cells of three random high-power fields (40x) in each well, and all groups are performed in quadruplicate. The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g., gene therapy), agonists, and/or antagonists of TRID. Example 22: Stimulation of Nitric Oxide Production by Endothelial Cells Nitric oxide released by the vascular endothelium is believed to be a mediator of vascular endothelium relaxation. Thus, TRID activity can be assayed by determining nitric oxide production by endothelial cells in response to TRID. Nitric oxide is measured in 96-well plates of confluent microvascular endothelial cells after 24 hours starvation and a subsequent 4 hr exposure to various levels of a positive control (such as VEGF-1) and TRID. Nitric oxide in the medium is determined by use ofthe Griess reagent to measure total nitrite after reduction of nitric oxide-derived nitrate by nitrate reductase . The effect of TRID on nitric oxide release is examined on HUVEC. Briefly, NO release from cultured HUVEC monolayer is measured with aNO-specific polarographic electrode connected to a NO meter (Iso-NO, World Precision Instruments Inc.). Calibration of the NO element is performed according to the following equation: 2 KNO 2 + 2 KI + 2 H 2 SO 4 6 2 NO + I, + 2 H 2 O + 2 K 2 SO 4 The standard calibration curve is obtained by adding graded concentrations of KNO 2 (0, 5, 10, 25, 50, 100, 250, and 500 nmol/L) into the calibration solution containing KI and H 2 SO 4 . The specificity of the Iso-NO electrode to NO is previously determined by measurement of NO from authentic NO gas. The culture medium is removed and HUVECs are washed twice with Dulbecco's phosphate buffered saline. The cells are then bathed in 5 ml of filtered Krebs-Henseleit solution in 6-well plates, and the cell plates are kept on a slide warmer (Lab Line Instruments Inc.) to maintain the temperature at 37°C. The NO sensor probe is inserted vertically into the wells, keeping the tip ofthe electrode 2 mm under the surface of the solution, before addition of the different conditions. S-nitroso acetyl penicillamin (SNAP) is used as a positive control. The amount of released NO is expressed as picomoles per lxl 0 6 endothelial cells. All values reported are means of four to six measurements in each group (number of cell culture wells). See, Leak et al. Biochem. and Biophys. Res. Comm. 277:96-105 (1995). The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g., gene therapy), agonists, and/or antagonists of TRID. Example 23: Effect of TRID on Cord Formation in Angiogenesis Another step in angiogenesis is cord formation, marked by differentiation of endothelial cells. This bioassay measures the ability of microvascular endothelial cells to form capillary-like structures (hollow structures) when cultured in vitro. CADMEC (microvascular endothelial cells) are purchased from Cell Applications, Inc. as proliferating (passage 2) cells and are cultured in Cell Applications' CADMEC Growth Medium and used at passage 5. For the in vitro angiogenesis assay, the wells of a 48-well cell culture plate are coated with Cell Applications' Attachment Factor Medium (200 μl/well) for 30 min. at 37°C. CADMEC are seeded onto the coated wells at 7,500 cells/well and cultured overnight in Growth Medium. The Growth Medium is then replaced with 300 μg Cell Applications' Chord Formation Medium containing control buffer or TRID (0.1 to 100 ng/ml) and the cells are cultured for an additional 48.hr. The numbers and lengths of the capillary-like chords are quantitated through use of the Boeckeler VIA- 170 video image analyzer. All assays are done in triplicate. Commercial (R&D) VEGF (50 ng/ml) is used as a positive control, b-esteradiol (1 ng/ml) is used as a negative control. The appropriate buffer (without protein) is also utilized as a control. The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g., gene therapy), agonists, and/or antagonists of TRID. Example 24: Angiogenic Effect on Chick Chorioallantoic Membrane Chick chorioallantoic membrane (CAM) is a well-established system to examine angiogenesis. Blood vessel formation on CAM is easily visible and quantifiable. The ability of TRID to stimulate angiogenesis in CAM can be examined. Fertilized eggs of the White Leghorn chick (Gallus gallus) and the Japanese quail (Coturnix coturnix) are incubated at 37.8°C and 80% humidity. Differentiated CAM of 16-day-old chick and 13 -day-old quail embryos is studied with the following methods. On Day 4 of development, a window is made into the egg shell of chick eggs. The embryos are checked for normal development and the eggs sealed with cellotape. They are further incubated until Day 13. Thermanox coverslips (Nunc, Naperville, IL) are cut into disks of about 5 mm in diameter. Sterile and salt-free growth factors, and the protein to be tested, are dissolved in distilled water and about 3.3 mg/ 5 ml are pipetted on the disks. After air-drying, the inverted disks are applied on CAM. After 3 days, the specimens are fixed in 3% glutaraldehyde and 2% formaldehyde and rinsed in 0.12 M sodium cacodylate buffer. They are photographed with a stereo microscope [Wild M8] and embedded for semi- and ultrathin sectioning as described above. Controls are performed with carrier disks alone. The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g., gene therapy), agonists, and/or antagonists of TRID. Example 25: Angiogenesis Assay Using a Matrigel Implant in Mouse In order to establish an in vivo model for angiogenesis to test TRID protein activities, mice and rats are implanted subcutaneously with methylcellulose disks containing either 20 mg of BSA (negative control), 1 mg of TRID, or 0.5 mg of VEGF-1 (positive control). The negative control disks should contain little vascularization, while the positive control disks should show signs of vessel formation. The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g., gene therapy), agonists, and/or antagonists of TRID. Example 26: Rescue of Ischemia in Rabbit Lower Limb Model To study the in vivo effects of TRID on ischemia, a rabbit hindlimb ischemia model is created by surgical removal of one femoral arteries as described previously (Takeshita, S. et al, Am J. Pathol 747:1649-1660 (1995)). The excision ofthe femoral artery results in retrograde propagation of thrombus and occlusion ofthe external iliac artery. Consequently, blood flow to the ischemic limb is dependent upon collateral vessels originating from the internal iliac artery (Takeshita, S. et al, Am J. Pathol 747: 1649-1660 (1995)). An interval of 10 days is allowed for post-operative recovery of rabbits and development of endogenous collateral vessels. At 10 day post-operatively (day 0), after performing a baseline angiogram, the internal iliac artery ofthe ischemic limb is transfected with 500 mg naked TRID expression plasmid by arterial gene transfer technology using a hydrogel-coated balloon catheter as described (Riessen, R. et al, Hum Gene Ther. 4:749-758 (1993); Leclerc, G. et al, J. Clin, Invest. 90: 936- 944 (1992)). When TRID is used in the treatment, a single bolus of 500 mg TRID protein or control is delivered into the internal iliac artery of the ischemic limb over a period of 1 min. through an infusion catheter. On day 30, various parameters are measured in these rabbits: (a) BP ratio - The blood pressure ratio of systolic pressure ofthe ischemic limb to that of normal limb; (b) Blood Flow and Flow Reserve - Resting FL: the blood flow during undilated condition and Max FL: the blood flow during fully dilated condition (also an indirect measure ofthe blood vessel amount) and Flow Reserve is reflected by the ratio of max FL: resting FL; (c) Angiographic Score - This is measured by the angiogram of collateral vessels. A score is determined by the percentage of circles in an overlaying grid that with crossing opacified arteries divided by the total number m the rabbit thigh; (d) Capillary density - The number of collateral capillaries determined in light microscopic sections taken from hindlimbs. The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g., gene therapy), agonists, and/or antagonists of TRID. Example 27: Rat Ischemic Skin Flap Model The evaluation parameters include skin blood flow, skin temperature, and factor VIII immunohistochemistry or endothelial alkaline phosphatase reaction. TRID expression, during the skin ischemia, is studied using in situ hybridization. The study in this model is divided into three parts as follows: a) Ischemic skin b) Ischemic skin wounds c) Normal wounds The experimental protocol includes: a) Raising a 3x4 cm, single pedicle full-thickness random skin flap (myocutaneous flap over the lower back ofthe animal). b) An excisional wounding (4-6 mm in diameter) in the ischemic skin (skin-flap). c) Topical treatment with TRID ofthe excisional wounds (day 0, 1 , 2, 3, 4 post- wounding) at the following various dosage ranges: lmg to 100 mg. d) Harvesting the wound tissues at day 3, 5, 7, 10, 14 and 21 post-wounding for histological, immunohistochemical, and in situ studies. The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g. , gene therapy), agonists, and/or antagonists of TRID. Example 28: Peripheral Arterial Disease Model Angiogenic therapy using TRID is a novel therapeutic strategy to obtain restoration of blood flow around the ischemia in case of peripheral arterial diseases. The experimental protocol includes: a) One side ofthe femoral artery is ligated to create ischemic muscle of the hindlimb, the other side of hindlimb serves as a control. b) TRID protein, in a dosage range of 20 mg - 500 mg, is delivered intravenously and/or intramuscularly 3 times (perhaps more) per week for 2-3 weeks. c) The ischemic muscle tissue is collected after ligation ofthe femoral artery at 1, 2, and 3 weeks for the analysis of TRID expression and histology. Biopsy is also performed on the other side of normal muscle ofthe contralateral hindlimb. The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g. gene therapy), agonists, and/or antagonists of TRID. Example 29: Ischemic Myocardial Disease Model TRID is evaluated as a potent mitogen capable of stimulating the development of collateral vessels, and restructuring new vessels after coronary artery occlusion. Alteration of TRID expression is investigated in situ. The experimental protocol includes: a) The heart is exposed through a left-side thoracotomy in the rat. Immediately, the left coronary artery is occluded with a thin suture (6-0) and the thorax is closed. b) TRID protein, in a dosage range of 20 mg - 500 mg, is delivered intravenously and/or intramuscularly 3 times (perhaps more) per week for 2-4 weeks. c) Thirty days after the surgery, the heart is removed and cross-sectioned for moφhometric and in situ analyzes. The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g., gene therapy), agonists, and/or antagonists of TRID. Example 30: Rat Corneal Wound Healing Model This animal model shows the effect of TRID on neovascularization. The experimental protocol includes: a) Making a 1-1.5 mm long incision from the center of cornea into the stromal layer. b) Inserting a spatula below the lip of the incision facing the outer corner ofthe eye. c) Making a pocket (its base is 1-1.5 mm form the edge ofthe eye). d) Positioning a pellet, containing 50ng- 5ug of TRID, within the pocket. e) TRID treatment can also be applied topically to the corneal wounds in a dosage range of 20mg - 500mg (daily treatment for five days). The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g., gene therapy), agonists, and/or antagonists of TRID. Example 31: Diabetic Mouse and Glucocorticoid-Impaired Wound Healing Models A. Diabetic db+/db+ Mouse Model. To demonstrate that TRID accelerates the healing process, the genetically diabetic mouse model of wound healing is used. The full thickness wound healing model in the db+/db+ mouse is a well characterized, clinically relevant and reproducible model of impaired wound healing. Healing ofthe diabetic wound is dependent on formation of granulation tissue and re-epithelialization rather than contraction (Gartner, M.H. et al, J. Surg Res. 52:389 (1992); Greenhalgh, D.G. et al, Am. J. Pathol. 136: 235 (1990)). The diabetic animals have many ofthe characteristic features observed in Type II diabetes mellitus. Homozygous (db+/db+) mice are obese in comparison to their normal heterozygous (db+/+m) littermates. Mutant diabetic (db+/db+) mice have a single autosomal recessive mutation on chromosome 4 (db+) (Coleman et al. Proc. Natl. Acad. Sci. USA 77:283-293 (1982)). Animals show polyphagia, polydipsia and polyuria. Mutant diabetic mice (db+/db+) have elevated blood glucose, increased or normal insulin levels, and suppressed cell- mediated immunity (Mandel et al. , J. Immunol. 720:1375 (1978); Debray-Sachs, M. et al, Clin. Exp. Immunol. 51(l): l-l (1983); Letter et al, Am. J. of Pathol 774:46-55 (1985)). Peripheral neuropathy, myocardial complications, and microvascular lesions, basement membrane thickening and glomerular filtration abnormalities have been described in these animals (Norido, F. et al , Exp. Neurol 83(2) :221 -232 ( 1984); Robertson et al. , Diabetes 29(1):60-61 ( 1980); Giacomelli etal, Lab Invest. 40(4):460-413 (1979); Coleman, O.L., Diabetes 31 (Suppl): \-6 ( 1982)). These homozygous diabetic mice develop hyperglycemia that is resistant to insulin analogous to human type II diabetes (Mandel et al, J. Immunol. 720:1375-1377 (1978)). The characteristics observed in these animals suggests that healing in this model may be similar to the healing observed in human diabetes (Greenhalgh, et al, Am. J. of Pathol. 136:1235-1246 (1990)). Genetically diabetic female C57BL/KsJ (db+/db+) mice and their non- diabetic (db+/+m) heterozygous littermates are used in this study (Jackson Laboratories). The animals are purchased at 6 weeks of age and were 8 weeks old at the beginning ofthe study. Animals are individually housed and received food and water ad libitum. All manipulations are performed using aseptic techniques. The experiments are conducted according to the rules and guidelines of Human Genome Sciences, Inc. Institutional Animal Care and Use Committee and the Guidelines for the Care and Use of Laboratory Animals. Wounding protocol is performed according to previously reported methods (Tsuboi, R. and Rifkin, D.B., J. Exp. Med. 772:245-251 (1990)). Briefly, on the day of wounding, animals are anesthetized with an intraperitoneal injection ofAvertin (0.01 mg/mL), 2,2,2-tribromoethanol and 2-methyl-2-butanol dissolved in deionized water. The dorsal region ofthe animal is shaved and the skin washed with 70% ethanol solution and iodine. The surgical area is dried with sterile gauze prior to wounding. An 8 mm full-thickness wound is then created using a Keyes tissue punch. Immediately following wounding, the surrounding skin is gently stretched to eliminate wound expansion. The wounds are left open for the duration ofthe experiment. Application ofthe treatment is given topically for 5 consecutive days commencing on the day of wounding. Prior to treatment, wounds are gently cleansed with sterile saline and gauze sponges. Wounds are visually examined and photographed at a fixed distance at the day of surgery and at two day intervals thereafter. Wound closure is determined by daily measurement on days 1-5 and on day 8. Wounds are measured horizontally and vertically using a calibrated Jameson caliper. Wounds are considered healed if granulation tissue is no longer visible and the wound is covered by a continuous epithelium. TRID is administered using at a range different doses of TRID, from 4mg to 500mg per wound per day for 8 days in vehicle. Vehicle control groups received 50mL of vehicle solution. Animals are euthanized on day 8 with an intraperitoneal injection of sodium pentobarbital (300mg/kg). The wounds and surrounding skin are then harvested for histology and immunohistochemistry. Tissue specimens are placed in 10% neutral buffered formalin in tissue cassettes between biopsy sponges for further processing. Three groups of 10 animals each (5 diabetic and 5 non-diabetic controls) are evaluated: 1) Vehicle placebo control, 2) TRID. Wound closure is analyzed by measuring the area in the vertical and horizontal axis and obtaining the total square area ofthe wound. Contraction is then estimated by establishing the differences between the initial wound area (day 0) and that of post treatment (day 8). The wound area on day 1 was 64mm 2 , the corresponding size of the dermal punch. Calculations were made using the following formula: [Open area on day 8] - [Open area on day 1] / [Open area on day 1] Specimens are fixed in 10% buffered formalin and paraffin embedded blocks are sectioned peφendicular to the wound surface (5mm) and cut using a Reichert-Jung microtome. Routine hematoxylin-eosin (H&E) staining is performed on cross-sections of bisected wounds. Histologic examination ofthe wounds are used to assess whether the healing process and the moφhologic appearance of the repaired skin is altered by treatment with TRID. This assessment included verification of the presence of cell accumulation, inflammatory cells, capillaries, fibroblasts, re-epithelialization and epidermal maturity (Greenhalgh, D.G. et α/., Λm. J. Pathol 75(5. 1235 (1990)). A calibrated lens micrometer is used by a blinded observer. Tissue sections are also stained immunohistochemically with a polyclonal rabbit anti-human keratin antibody using ABC Elite detection system. Human skin is used as a positive tissue control while non-immune IgG is used as a negative control. Keratinocyte growth is determined by evaluating the extent of reepithelialization ofthe wound using a calibrated lens micrometer. Proliferating cell nuclear antigen/cyclin (PCNA) in skin specimens is demonstrated by using anti-PCNA antibody (1 :50) with an ABC Elite detection system. Human colon cancer served as a positive tissue control and human brain tissue is used as a negative tissue control. Each specimen included a section with omission ofthe primary antibody and substitution with non-immune mouse IgG. Ranking of these sections is based on the extent of proliferation on a scale of 0-8, the lower side of the scale reflecting slight proliferation to the higher side reflecting intense proliferation. Experimental data are analyzed using an unpaired t test. A p value of < 0.05 is considered significant. B. Steroid Impaired Rat Model The inhibition of wound healing by steroids has been well documented in various in vitro and in vivo systems (Wahl. S.M. Glucocorticoids and Wound healing. In: Anti-Inflammatory Steroid Action: Basic and Clinical Aspects.280- 302 (1989); Wahl, S.M.et al, J. Immunol. 775: 476-481 (1975); Werb, Z. etal., J Exp. Med. 747: 1684-1694 (1978)). Glucocorticoids retard wound healing by inhibiting angiogenesis, decreasing vascular permeability ( Ebert, R.H., etal, An. Intern. Med. 57:701-705 (1952)), fibroblast proliferation, and collagen synthesis (Beck, L.S. et al, Growth Factors. 5: 295-304 (1991); Haynes, B.F. et al, J. Clin. Invest. 61: 703-797 (1978)) and producing a transient reduction of circulating monocytes (Haynes, B.F., et al, J. Clin. Invest. 61: 703-797 (1978); Wahl, S. M., "Glucocorticoids and wound healing", In: Antiinflammatory Steroid Action: Basic and Clinical Aspects, Academic Press, New York, pp. 280-302 (1989)). The systemic administration of steroids to impaired wound healing is a well establish phenomenon in rats (Beck, L.S. et al, Growth Factors. 5: 295- 304 (1991); Haynes, B.F., et al, J. Clin. Invest. 61: 703-797 (1978); Wahl, S. M., "Glucocorticoids and wound healing", In: Antiinflammatory Steroid Action: Basic and Clinical Aspects, Academic Press, New York, pp. 280-302 (1989); Pierce, G.F. et al, Proc. Natl. Acad. Sci. USA 86: 2229-2233 (1989)). To demonstrate that TRID can accelerate the healing process, the effects of multiple topical applications of TRID on full thickness excisional skin wounds in rats in which healing has been impaired by the systemic administration of methylprednisolone is assessed. Young adult male Sprague Dawley rats weighing 250-300 g (Charles River Laboratories) are used in this example. The animals are purchased at 8 weeks of age and were 9 weeks old at the beginning ofthe study. The healing response of rats is impaired by the systemic administration of methylprednisolone (17mg/kg/rat intramuscularly) at the time of wounding. Animals are individually housed and received food and water ad libitum. All manipulations are performed using aseptic techniques. This study is conducted according to the rules and guidelines of Human Genome Sciences, Inc. Institutional Animal Care and Use Committee and the Guidelines for the Care and Use of Laboratory Animals. The wounding protocol is followed according to section A, above. On the day of wounding, animals are anesthetized with an intramuscular injection of ketamine (50 mg/kg) and xylazine (5 mg/kg). The dorsal region ofthe animal is shaved and the skin washed with 70% ethanol and iodine solutions. The surgical area is dried with sterile gauze prior to wounding. An 8 mm full-thickness wound is created using a Keyes tissue punch. The wounds are left open for the duration of the experiment. Applications ofthe testing materials are given topically once a day for 7 consecutive days commencing on the day of wounding and subsequent to methylprednisolone administration. Prior to treatment, wounds are gently cleansed with sterile saline and gauze sponges. Wounds are visually examined and photographed at a fixed distance at the day of wounding and at the end of treatment. Wound closure is determined by daily measurement on days 1 -5 and on day 8 for Figure. Wounds are measured horizontally and vertically using a calibrated Jameson caliper. Wounds are considered healed if granulation tissue was no longer visible and the wound is covered by a continuous epithelium. TRID is administered using at a range different doses of TRID, from 4mg to 500mg per wound per day for 8 days in vehicle. Vehicle control groups received 50mL of vehicle solution. Animals are euthanized on day 8 with an intraperitoneal injection of sodium pentobarbital (300mg/kg). The wounds and surrounding skin are then harvested for histology. Tissue specimens are placed in 10% neutral buffered formalin in tissue cassettes between biopsy sponges for further processing. Four groups of 10 animals each (5 with methylprednisolone and 5 without glucocorticoid) were evaluated: 1) Untreated group 2) Vehicle placebo control 3) TRID treated groups. Wound closure is analyzed by measuring the area in the vertical and horizontal axis and obtaining the total area of the wound. Closure is then estimated by establishing the differences between the initial wound area (day 0) and that of post treatment (day 8). The wound area on day 1 was 64mm 2 , the corresponding size of the dermal punch. Calculations were made using the following formula: [Open area on day 8] - [Open area on day 1] / [Open area on day 1] Specimens are fixed in 10% buffered formalin and paraffin embedded blocks are sectioned peφendicular to the wound surface (5mm) and cut using an Olympus microtome. Routine hematoxylin-eosin (H&E) staining was performed on cross-sections of bisected wounds. Histologic examination of the wounds allows assessment of whether the healing process and the moφhologic appearance of the repaired skin was improved by treatment with TRID. A calibrated lens micrometer is used by a blinded observer to determine the distance ofthe wound gap- Experimental data are analyzed using an unpaired t test. A p value of < 0.05 is considered significant. The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g. , gene therapy), agonists, and/or antagonists of TRID. Example 32: Lymphadema Animal Model The puφose of this experimental approach is to create an appropriate and consistent lymphedema model for testing the therapeutic effects of TRID in lymphangiogenesis and re-establishment ofthe lymphatic circulatory system in the rat hind limb. Effectiveness is measured by swelling volume ofthe affected limb, quantification ofthe amount of lymphatic vasculature, total blood plasma protein, and histopathology . Acute lymphedema is observed for 7- 10 days. Perhaps more importantly, the chronic progress ofthe edema is followed for up to 3-4 weeks. Prior to beginning surgery, blood sample is drawn for protein concentration analysis. Male rats weighing approximately ~350g are dosed with Pentobarbital. Subsequently, the right legs are shaved from knee to hip. The shaved area is swabbed with gauze soaked in 70% EtOH. Blood is drawn for serum total protein testing. Circumference and volumetric measurements are made prior to injecting dye into paws after marking 2 measurement levels (0.5 cm above heel, at mid-pt of dorsal paw). The intradermal dorsum of both right and left paws are injected with 0.05 ml of 1% Evan's Blue. Circumference and volumetric measurements are then made following injection of dye into paws. Using the knee joint as a landmark, a mid-leg inguinal incision is made circumferentially allowing the femoral vessels to be located. Forceps and hemostats are used to dissect and separate the skin flaps. After locating the femoral vessels, the lymphatic vessel that runs along side and underneath the vessel(s) is located. The main lymphatic vessels in this area are then electrically coagulated or suture ligated. Using a microscope, muscles in back ofthe leg (near the semitendinosis and adductors) are bluntly dissected. The popliteal lymph node is then located. The 2 proximal and 2 distal lymphatic vessels and distal blood supply of the popliteal node are then and ligated by suturing. The popliteal lymph node, and any accompanying adipose tissue, is then removed by cutting connective tissues. Care is taken to control any mild bleeding resulting from this procedure. After lymphatics are occluded, the skin flaps are sealed by using liquid skin (Vetbond) (AJ Buck). The separated skin edges are sealed to the underlying muscle tissue while leaving a gap of -0.5 cm around the leg. Skin also may be anchored by suturing to underlying muscle when necessary. To avoid infection, animals are housed individually with mesh (no bedding). Recovering animals are checked daily through the optimal edematous peak, which typically occurred by day 5-7. The plateau edematous peak are then observed. To evaluate the intensity of the lymphedema, the circumference and volumes of 2 designated places on each paw before operation and daily for 7 days are measured. The effect plasma proteins on lymphedema is determined and whether protein analysis is a useful testing perimeter is also investigated. The weights of both control and edematous limbs are evaluated at 2 places. Analysis is performed in a blind manner. Circumference Measurements: Under brief gas anesthetic to prevent limb movement, a cloth tape is used to measure limb circumference. Measurements are done at the ankle bone and dorsal paw by 2 different people then those 2 readings are averaged. Readings are taken from both control and edematous limbs. Volumetric Measurements: On the day of surgery, animals are anesthetized with Pentobarbital and are tested prior to surgery. For daily volumetrics animals are under brief halothane anesthetic (rapid immobilization and quick recovery), both legs are shaved and equally marked using waterproof marker on legs. Legs are first dipped in water, then dipped into instrument to each marked level then measured by Buxco edema software(Chen/Victor). Data is recorded by one person, while the other is dipping the limb to marked area. Blood-plasma protein measurements: Blood is drawn, spun, and serum separated prior to surgery and then at conclusion for total protein and Ca2+ comparison. Limb Weight Comparison: After drawing blood, the animal is prepared for tissue collection. The limbs were amputated using a quillitine, then both experimental and control legs were cut at the ligature and weighed. A second weighing is done as the tibio-cacaneal joint was disarticulated and the foot was weighed. Histological Preparations: The transverse muscle located behind the knee (popliteal) area is dissected and arranged in a metal mold, filled with FreezeGel, dipped into cold methylbutane, placed into labeled sample bags at - 80° C until sectioning. Upon sectioning, the muscle was observed under fluorescent microscopy for lymphatics. Other immuno/histological methods are currently being evaluated. The studies described in this example test the activity in TRID protein. However, one skilled in the art could easily modify the exemplified studies to test the activity of TRID polynucleotides (e.g. , gene therapy), agonists, and/or antagonists of TRID. It will be clear that the invention may be practiced otherwise than as particularly described in the foregoing description and examples. Numerous modifications and variations ofthe present invention are possible in light ofthe above teachings and, therefore, are within the scope ofthe appended claims. The entire disclosure of each document cited (including patents, patent applications, journal articles, abstracts, laboratory manuals, books, or other disclosures) in the Background of the Invention, Detailed Description, and Examples is hereby incoφorated herein by reference. Further, the Sequence Listing submitted herewith, in paper form, is hereby incoφorated by reference in its entirety. Applicant's or agent's file International application No, reference number: 1488.128PC05 TBA TO M 00 / 1 351 3 INDICATIONS RELATING TO A DEPOSITED MICROORGANISM (PCT Rule I3bιs) A. The indications made below relate to the microorganism referred to in the description on page 5, line 6 B. IDENTIFICATION OF DEPOSIT Further deposits are identified on an additional sheet d Name of depository institution American Type Culture Collection Address of depository institution (including postal code and country) 10801 University Boulevard Manassas, Virginia 20110-2209 United States of Ameπca Date of deposit Accession Number 20 November 1996 (20.11.96) 97798 C. ADDITIONAL INDICATIONS (leave blank if not applicable) Tfos information is continued on an additional sheet □ DNA Plasmid 1658760 D. DESIGNATED STATES FOR WHICH INDICATIONS ARE MADE (if the indications are not for all designated States) E. SEPARATE FURNISHING OF INDICATIONS (leave blank if not applicable) The indications listed below will be submitted to the international Bureau later (specify the general nature ofthe indications, e ι "Accession Number of Deposit") For International Bureau use only Cl This sheet was received by the International Bureau on Authoπzed officer Form PCT/RO/l 34 (July 1992) 1 2 8deposιt jp

Claims: What Is Claimed Is: 1. A method for treating graft versus host disease, viral infection, cancer, leukemia, immunodeficiency, or an autoimmune disorder comprising administering to an individual therapeutically effective amounts of: (a) a first therapeutic agent comprising an antibody capable of binding to a polypeptide consisting of amino acids 27 to 259 of SEQ ID NO:2; and (b) a second therapeutic agent selected from 1 consisting of: (i) TRAIL; (ϋ) a tumor necrosis factor; (ϋi) a tumor necrosis factor blocking agent; (iv) an immunosuppressive agent; (v) an antibiotic; (vi) an anti-inflammatory agent; (vϋ) a chemotherapeutic agent; and (viii) a cytokine. 2. The method of claim 1, wherein said first therapeutic agent comprises an antibody which binds to a polypeptide consisting of amino acids 27 to 240 of SEQ ID NO:2. 3. The method of claim 1, wherein said antibody is a monoclonal antibody. 4. The method of claim 1 , wherein said antibody is a polyclonal antibody. 5. The method of claim 1 , wherein said antibody is a humanized antibody. 6. The method of claim 1 , wherein said antibody is an antibody fragment. 7. The method of claim 6, wherein said antibody fragment is a single- chain Fv antibody fragment. 8. The method of claim 6, wherein said antibody fragment is an Fab antibody fragment. 9. The method of claim 1 , wherein said first and second therapeutic agents are administered to the individual at the same time. 10. The method of claim 1 , wherein said first and second therapeutic agents are administered to the individual at different times. 11. The method of claim 1 , wherein said second therapeutic agent is TRAIL. 12. The method of claim 1 , wherein said tumor necrosis factor blocking agent comprises an antibody which binds to a protein selected from the group consisting of: (a) TNF-α; (b) TNF-β; (c) TNF-γ; (d) TNF-γ-α; and (e) TNF-γ-β. 13. The method of claim 1 , wherein said immunosuppressive agent is selected from the group consisting of: (a) cyclosporine; (b) cyclophosphamide; (c) methy lpredni sone ; (d) prednisone; (e) azathioprine; (f) FK-506; and (g) 15-deoxyspergualin. 14. The method of claim 1 , wherein said cytokine is selected from the consisting of: (a) IL-2; (b) IL-3; (c) IL-4; (d) IL-5; (e) IL-6; (f) IL-7; (g) IL-10; (h) IL-12; (i) IL-13; G) IL-15; and (k) IFN-γ. 15. A composition comprising: (a) a first therapeutic agent comprising an antibody which binds to a polypeptide consisting of amino acids 1 to 259 of SEQ ID NO:2; and (b) a second therapeutic agent selected from the group consisting of: (i) TRAIL; (ii) a tumor necrosis factor; (iii) a tumor necrosis factor blocking agent; (iv) an immunosuppressive agent; (v) an antibiotic; (vi) an anti-inflammatory agent; (vii) a chemotherapeutic agent; and (viii) a cytokine. 16. The composition of claim 15, which further comprises a pharmaceutically acceptable carrier or excipient. 17. An isolated polypeptide comprising an amino acid sequence at least 90% identical to amino acids 27 to 240 of SEQ ID NO:2; wherein said polypeptide is covalently attached to polyethylene glycol, said polyethylene glycol having an average molecule weight selected from the group consisting of 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10,000, 15,000, and 20,000. 18. The polypeptide of claim 17, comprising an amino acid sequence at least 95% identical to amino acids 27 to 240 of SEQ ID NO:2. 19. The polypeptide of claim 18, wherein said amino acid sequence comprises amino acids 27 to 240 of SEQ ID NO:2. 20. The polypeptide of claim 17, wherein said polypeptide has an average degree of substitution with polyethylene glycol which falls within a range selected from the group consisting of 1-3, 2-4, 3-5, 4-6, 5-7, 6-8, 7-9, 8-10, 9-1 1, and 10-12. 21. The polypeptide of claim 17, which is produced by a recombinant host cell. 22. The polypeptide of claim 21 , wherein said recombinant host cell which is a eukaryotic host cell. 23. The polypeptide of claim 17, which comprises a heterologous polypeptide. 24. The polypeptide of claim 23, wherein said heterologous polypeptide comprises an Fc portion of an antibody. 25. A composition comprising the polypeptide of claim 17 and a pharmaceutically acceptable carrier.

Inventors: GENTZ REINER L, NI JIAN, RUBEN STEVEN M, WEI YING-FEI, GENTZ, REINER, L., NI, JIAN, RUBEN, STEVEN, M., WEI, YING-FEI
Applicants: GENTZ REINER L, HUMAN GENOME SCIENCES INC, NI JIAN, RUBEN STEVEN M, WEI YING FEI, GENTZ, REINER, L., HUMAN GENOME SCIENCES, INC., NI, JIAN, RUBEN, STEVEN, M., WEI, YING-FEI
Application year: 2000
Main classification: A61K38
IPC codes: A61K31, A61K38, A61K39, A61K45, A61K48, A61P1, A61P3, A61P5, A61P7, A61P9, A61P11, A61P13, A61P17, A61P19, A61P21, A61P25, A61P27, A61P29, A61P31, A61P33, A61P35, A61P37, C07K14, C07K16, C07K19, C12N1, C12N5, C12N15, C12P21