REGULATION OF HUMAN DENDRITIC CELL IMMUNORECEPTOR

Abstract: Reagents which regulate human dendritic cell immunoreceptor and reagents which bind to human dendritic cell immunoreceptor gene products can play a role in preventing, ameliorating, or correcting dysfunctions or diseases including, but not limited to, cancer, asthma, obesity, diabetes, CNS disorders, and cardiovascular disorders.

Description: REGULATION OF HUMAN DENDRITIC CELL IMMUNORECEPTOR This application incorporates by reference co-pending application Serial No. 60/240,096 filed October 16, 2000. TECHNICAL FIELD OF THE INVENTION The invention relates to the area of receptor regulation. More particularly, the invention relates to the regulation of human dendritic cell immunoreceptor. BACKGROUND OF THE INVENTION Dendritic cells (DC) are unique among antigen presenting cells (APC) by virtue of their potent capacity to activate immunologically naive T cells (Steinman, 1991 ). U.S. Patent No. 6,046, 158; Banchereau & Steinman, Nature 1998 Mar 19;392(6673):245-52. DC express constitutively, or after maturation, several molecules that mediate physical interaction with and deliver activation signals to responding T cells. These include class I and class π MHC molecules, CDSO (B7-1) and CD86 (B7-2). CD40, CDtl a/CD18 (LFA-1), and CD54 (ICAM-1) (Steinman, 1991; Steinman et al., 1995). DC also secrete, upon stimulation, several T cell- stimulatory cytokines, including I -lβ, IL-6. 1L-8, macrophage-inflammatory protein-lα (MlP-lα) and M1P-1. delta. (Matsue. et al, 1992; Kitajima et al., 1995; Ariizumi et al., 1995; Caux et al., 1994; Heufler et al., 1992; Schreiber et al., 1992; Enk et al., 1992; Mohamadzadeh et al., 1996). Both of these properties, adhesion molecule expression and cytokine production are shared by other APC (e.g., activated macrophages and B cells), which are substantially less competent in activating naive T cells. T cell activation is an important step in the protective immunity against pathogenic microorganisms (e.g., viruses, bacteria, and parasites), foreign proteins, and harmful chemicals in the environment. T cells express receptors on their surface (i.e., T cell receptors) which recognize antigens presented on the surface of antigen-presenting cells. During a normal immune response, binding of these antigens to the T cell receptor initiates intracellular changes leading to T cell activation. DC express several different adhesion (and costimulatory) molecules, which mediate their interaction with T cells. The combinations of receptors (on DC) and counter- receptors (on T cells) that are known to play this role include: a) class I MHC and CD8, b) class II MHC and CD4, c) CD54 (ICAM-1) and CD11-JCD18 (LFA-1), d) ICAM-3 and CDl la/CD18, e) LFA-3 and CD2, f) CD80 (B7-1) and CD28 (and CTLA4), g) CD86 (B7-2) and CD28 (and CTLA4) and h) CD40 and CD40L (Steinman et al., 1995). Importantly, not only does ligation of these molecules promote physical binding between DC and T cells, it also transduces activation signals. C-type lectins are a family of glycoproteins that exhibit amino acid sequence similarities in their carbohydrate recognition domains (CRD) and that bind to selected carbohydrates in a Ca -dependent manner. C-type lectins have been subdivided into four categories (Vasta et al., 1994; Spiess 1990). The first group comprises type II membrane-integrated proteins, such as asialoglycoprotein receptors, macrophage galactose and N-acetyl glucosamine (GlcNac)-specifιc lectin, and CD23 (FcRII). Many members in this group exhibit specificity for galactose/fucose, galactosarnine/GalNac. or GlcNac residues. The second group includes cartilage and fibroblast proteoglycan core proteins. The third group includes the so-called "collectins" such as serum mannose-binding proteins, pulmonary surfactant protein SP-A, and conglutinin. The fourth group includes certain adhesion molecules which are known as LEC-CAMs (e.g., Mel-14, GMP-140, and ELAM-1). C-type lectins are known to function as agglutinins, opsonins, complement activators, and cell-associated recognition molecules (Vasta et al, 1994; Spiess 1990; Kery, 1991). For instance, macrophage mannose receptors serve a scavenger function (Shepherd et al., 1990), as well as mediating the uptake of pathogenic organisms, including Pnenmocystis carinii (Ezekowitz et al., 1991) and Candida albicans (Ezekowitz et al., 1990). Serum mannose-binding protein mimics Clq in its capacity to activate complement through the classical pathway. Importantly, genetic mutations in this lectin predispose for severe recurrent infections, diarrhea, and failure to thrive (Reid et al., 1994). Thus, C-type lectins exhibit diverse functions with biological significance. Importantly, carbohydrate moieties do not necessarily serve as "natural" ligands for C-type lectins. For example, CD23 (FCRII), which belongs to the C-type lectin family as verified by its binding of Gal-Gal-Nac (Kijimoto-Ochiai et al, 1994) and by its CRD sequence, is now known to recognize IgE in a carbohydrate-independent manner; an enzymatically deglycosylated form of IgE as well as recombinant (non- glycosylated) IgE produced in E. coli both bind to CD23 (Vercelli et al, 1989). Thus, some C-type lectins recognize polypeptide sequences in their natural ligands. Even more extreme is the recent hypothesis that a major biological function of lectins is the recognition of polypeptides, instead of carbohydrates, as suggested by the identification, from a random polypeptide library, of several polypeptide ligands for Con A, a prototypic plant lectin (Oldenburg et al., 1992). Recently, two C-type lectins have been identified on DC surfaces. First, Jiang et al. cloned the protein recognized by the NLDC-145 mAb, one of the most widely used mAb against murine DC (Jiang et al., 1995). This protein, now termed DEC-205, was found to be a new member of the C-type- lectin family, one that contains ten distinct CRD. Second, Sallusto et al reported that human DC express macrophage mannose receptors (MMR), which also contain multiple CRD (Sallusto et al., 1995). Both receptors have been proposed to mediate endocytosis of glycosylated molecules by DC, based on the observations that: a) polyclonal rabbit antibodies against DEC- 205 not only bound to DEC-205 on DC surfaces, but were subsequently internalized; b) these DC activated effectively a T cell line reactive to rabbit IgG; and c) intcrnalization of FITC-dextran by DC was blocked effectively with mannan, a mannose receptor competitor (Jiang et al., 1995; Sallusto et al, 1995). With respect to cell type specificity, DEC-205 is now known to be also expressed, albeit at lower levels, by B cells and epithelial cells in thymus, intestine, and lung (Witmer-Pack et al., 1995; Inaba et al., 1995) and MMR is also expressed even more abundantly by macrophages (Stahl 1992). Thus, there have been no C-type lectins that are expressed in a DC-specific manner. Fournier et al. have identified FDF03, an inhibitory receptor of the immunoglobulin superfamily, is expressed by human dendritic and myeloid cells. Immunol 165(3), 1 197-209, 2000. Bates et al. have identified a dendritic cell immunoreceptor, DCIR, which is a novel C-Type lectin surface receptor which contains an immunoreceptor tyrosine-based inhibitory motif. Journal of Immunology 163, 1973-1983, 1999. Because it is known that DC are far more potent than other APC in their capacity to activate immunologically naive T cells, it is probable that DC express a protein or proteins which function to activate T cells and which are not expressed by other APCs. Knowledge of the structure of such a protein or proteins would prove quite valuable in many areas. For example, the purified protein(s) could be used to identify its (or their) ligands expressed by T cells. Additionally, antibodies could be raised against the purified protein(s) and used to inhibit DC-mediated T cell activation. SUMMARY OF THE INVENTION It is an object of the invention to provide reagents and methods of regulating a human dendritic cell immunoreceptor. This and other objects of the invention are provided by one or more of the embodiments described below. One embodiment of the invention is a dendritic cell immunoreceptor polypeptide comprising an amino acid sequence selected from the group consisting of: amino acid sequences which are at least about 30% identical to the amino acid sequence shown in SEQ ID NO: 2; the amino acid sequence shown in SEQ ID NO: 2; amino acid sequences which are at least about 30% identical to the amino acid sequence shown in SEQ ID NO: 15; and the amino acid sequence shown in SEQ ID NO: 15. Yet another embodiment of the invention is a method of screening for agents which decrease extracellular matrix degradation. A test compound is contacted with a dendritic cell immunoreceptor polypeptide comprising an amino acid sequence selected from the group consisting of: amino acid sequences which are at least about 30% identical to the amino acid sequence shown in SEQ ID NO: 2; the amino acid sequence shown in SEQ ID NO: 2; amino acid sequences which are at least about 30% identical to the amino acid sequence shown in SEQ ID NO: 15; and the amino acid sequence shown in SEQ ID NO: 15. Binding between the test compound and the dendritic cell immunoreceptor polypeptide is detected. A test compound which binds to the dendritic cell immunoreceptor polypeptide is thereby identified as a potential agent for decreasing extracellular matrix degradation. The agent can work by decreasing the activity of the dendritic cell immunoreceptor. Another embodiment of the invention is a method of screening for agents which decrease extracellular matrix degradation. A test compound is contacted with a polynucleotide encoding a dendritic cell immunoreceptor polypeptide, wherein the polynucleotide comprises a nucleotide sequence selected from the group consisting of: nucleotide sequences which are at least about 50% identical to the nucleotide sequence shown in SEQ ID NO: 1; the nucleotide sequence shown in SEQ ID NO: 1; nucleotide sequences which are at least about 50% identical to the nucleotide sequence shown in SEQ ID NO: 14; and the nucleotide sequence shown in SEQ ID NO: 14. Binding of the test compound to the polynucleotide is detected. A test compound which binds to the polynucleotide is identified as a potential agent for decreasing extracellular matrix degradation. The agent can work by decreasing the amount of the dendritic cell immunoreceptor through interacting with the dendritic cell immunoreceptor m-RNA. Another embodiment of the invention is a method of screening for agents which regulate extracellular matrix degradation. A test compound is contacted with a dendritic cell immunoreceptor polypeptide comprising an amino acid sequence selected from the group consisting of: amino acid sequences which are at least about 30% identical to the amino acid sequence shown in SEQ ID NO: 2; the amino acid sequence shown in SEQ ID NO: 2; amino acid sequences which are at least about 30% identical to the amino acid sequence shown in SEQ ID NO: 15; and the amino acid sequence shown in SEQ ID NO: 15. A dendritic cell immunoreceptor activity of the polypeptide is detected. A test compound which increases dendritic cell immunoreceptor activity of the polypeptide relative to dendritic cell immunoreceptor activity in the absence of the test compound is thereby identified as a potential agent for increasing extracellular matrix degradation. A test compound which decreases dendritic cell immunoreceptor activity of the polypeptide relative to dendritic cell immunoreceptor activity in the absence of the test compound is thereby identified as a potential agent for decreasing extracellular matrix degradation. Even another embodiment of the invention is a method of screening for agents which decrease extracellular matrix degradation. A test compound is contacted with a dendritic cell immunoreceptor product of a polynucleotide which comprises a nucleotide sequence selected from the group consisting of: nucleotide sequences which are at least about 50% identical to the nucleotide sequence shown in SEQ ID NO: 1 ; the nucleotide sequence shown in SEQ ID NO: 1; nucleotide sequences which are at least about 50% identical to the nucleotide sequence shown in SEQ ID NO: 14; and the nucleotide sequence shown in SEQ ID NO: 14. Binding of the test compound to the dendritic cell immunoreceptor product is detected. A test compound which binds to the dendritic cell immunoreceptor product is thereby identified as a potential agent for decreasing extracellular matrix degradation. Still another embodiment of the invention is a method of reducing extracellular matrix degradation. A cell is contacted with a reagent which specifically binds to a polynucleotide encoding a dendritic cell immunoreceptor polypeptide or the product encoded by the polynucleotide, wherein the polynucleotide comprises a nucleotide sequence selected from the group consisting of: nucleotide sequences which are at least about 50% identical to the nucleotide sequence shown in SEQ ID NO: 1; the nucleotide sequence shown in SEQ ID NO: 1; nucleotide sequences which are at least about 50% identical to the nucleotide sequence shown in SEQ ID NO: 14; and the nucleotide sequence shown in SEQ ID NO: 14. Dendritic cell immunoreceptor activity in the cell is thereby decreased. The invention thus provides a human dendritic cell immunoreceptor whiGh can be used to identify test compounds which may act, for example, as agonists or antagonists at the receptor's ligand binding site. Human dendritic cell immunoreceptor and fragments thereof also are useful in raising specific antibodies which can block the receptor and effectively reduce its activity. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows the DNA-sequence encoding a dendritic cell immunoreceptor Polypeptide (SEQ ID NO: 1) Fig. 2 shows the amino acid sequence deduced from the DNA-sequence of Fig.1 (SEQ ID NO: 2). Fig. 3 shows the amino acid sequence of the protein identified by the Accession No. AJ133532 (SEQ ID NO: 3), Fig. 4 shows the DNA-sequence encoding a dendritic cell immunoreceptor Polypeptide (SEQ ID NO: 4). Fig. 5 shows the DNA-sequence encoding a dendritic cell immunoreceptor Polypeptide (SEQ ID NO: 5). Fig. 6 shows the DNA-sequence encoding a dendritic cell immunoreceptor Polypeptide (SEQ ID NO: 6). Fig. 7 shows the DNA-sequence encoding a dendritic cell immunoreceptor Polypeptide (SEQ ID NO: 7). Fig. 8 shows the DNA-sequence encoding a dendritic cell immunoreceptor Polypeptide (SEQ ID NO: 8). Fig. 9 shows the DNA-sequence encoding a dendritic cell immunoreceptor Polypeptide (SEQ ID NO: 9). Fig. 10 shows the DNA-sequence encoding a dendritic cell immunoreceptor Polypeptide (SEQ ID NO: 10). Fig. 11 shows the DNA-sequence encoding a dendritic cell immunoreceptor Polypeptide (SEQ ID NO: 11). Fig. 12 shows the DNA-sequence encoding a dendritic cell immunoreceptor Polypeptide (SEQ ID NO: 12). Fig. 13 shows the DNA-sequence encoding a dendritic cell immunoreceptor Polypeptide (SEQ ID NO: 13). Fig. 14 shows the amino acid sequence of a dendritic cell immunoreceptor Polypeptide (SEQ ID NO: 14). Fig. 15 shows the DNA-sequence encoding a -dendritic cell immunoreceptor Polypeptide (SEQ ID NO: 14). Fig. 16 shows the DNA-sequence encoding a dendritic cell immunoreceptor Polypeptide (SEQ 3D NO: 15). Fig. 1 7 shows the BLASTP - alignment of 273_genwisedb against pdb|lDV8|lDV8-A. Fig. 18 shows the HMMPFAM - alignment of 273_genwisedb against pfam|hmm|lectin_c. DETAILED DESCRIPTION OF THE INVENTION The invention relates to an isolated polynucleotide encoding a dendritic cell immunoreceptor polypeptide and being selected from the group consisting of: a) a polynucleotide encoding a dendritic cell immunoreceptor polypeptide comprising an amino acid sequence selected from the group consisting of: amino acid sequences which are at least about 30% identical to the amino acid sequence shown in SEQ ID NO: 2; the amino acid sequence shown in SEQ ID NO: 2; amino acid sequences which are at least about 30%> identical to the amino acid sequence shown in SEQ ID NO: 15; and the amino acid sequence shown in SEQ ID NO: 15; b) a polynucleotide comprising the sequence of SEQ ID NO: 1, or 14; c) a polynucleotide which hybridizes under stringent conditions to a polynucleotide specified in (a) and (b); d) a polynucleotide the sequence of which deviates from the polynucleotide sequences specified in (a) to (c) due to the degeneration of the genetic code; and e) a polynucleotide which represents a fragment, derivative or allelic variation of a polynucleotide sequence specified in (a) to (d). Furthermore, it has been discovered by the present applicant that a novel dendritic cell immunoreceptor, particularly a human dendritic cell immunoreceptor, is a discovery of the present invention. Human dendritic cell immunoreceptor comprises the amino acid sequence shown in SEQ ID NOS: 2 and 15. A coding sequence for human dendritic cell immunoreceptor is shown in SEQ ID NOS: 1 and 14. Related ESTs (SEQ LO NOS: 4-13) are expressed in lung and liver. Human dendritic cell immunoreceptor is 28% identical over 132 amino acids to the carbohydrate recognition domain "pdb|lDV8|lDV8-A" (Fig. 17). Human dendritic cell immunoreceptor also contains a lectin C-type domain (Fig. 18). Human dendritic cell immunoreceptor of the invention is expected to be useful for the same purposes as previously identified receptors of this type. Human dendritic cell immunoreceptor is believed to be useful in therapeutic methods to treat disorders such as cancer, asthma, obesity, diabetes, CNS disorders, and cardiovascular disorders. Human dendritic cell immunoreceptor also can be used to screen for human dendritic cell immunoreceptor agonists and antagonists. Polypeptide Human dendritic cell immunoreceptor polypeptides according to the invention comprise at least 6, 10, 15, 20, 25, 50, 75, 100, 125, or 134 contiguous amino acids selected from the amino acid sequence shown in SEQ ID NO: 2 or a biologically active variant thereof, as defined below. Human dendritic cell immunoreceptor polypeptides according to the invention comprise at least 6, 10, 15, 20, 25, 50, 75, 100, 125, or 148 contiguous amino acids selected from the amino acid sequence shown in SEQ ID NO: 15 or a biologically active variant thereof, as defined below, A dendritic cell immunoreceptor polypeptide of the invention therefore can be a portion of a dendritic cell immunoreceptor protein, a full-length dendritic cell immunoreceptor protein, or a fusion protein comprising all or a portion of a dendritic cell immunoreceptor protein. Biologically Active Variants Human dendritic cell immunoreceptor polypeptide variants which are biologically active, e.g., retain a ligand binding activity, also are dendritic cell immunoreceptor polypeptides. Preferably, naturally or non-naturally occurring dendritic cell immunoreceptor polypeptide variants have amino acid sequences which are at least about 30, 35, 40, 45, 50, 55, 60, 65, or 70, preferably about 75, 80, 85, 90, 96, 96, or 98% identical to the amino acid sequence shown in SEQ ID NOS: 2 and 15 or a fragment thereof. Percent identity between a putative dendritic cell immunoreceptor polypeptide variant and an amino acid sequence of SEQ ID NOS: 2 and 15 is determined using the Blast2 alignment program (Blosum62, Expect 10, standard genetic codes). Variations in percent identity can be due, for example, to amino acid substitutions, insertions, or deletions. Amino acid substitutions arc defined as one for one amino acid replacements. They are conservative in nature when the substituted amino acid has similar structural and/or chemical properties. Examples of conservative replacements are substitution of a leucine with an isoleucine or valine, an aspartate with a glutamate, or a threonine with a serine. Amino acid insertions or deletions are changes to or within an amino acid sequence. They typically fall in the range of about 1 to 5 amino acids. Guidance in determining which amino acid residues can be substituted, inserted, or deleted without abolishing biological or immunological activity of a dendritic cell immunoreceptor polypeptide can be found using computer programs well known in the art, such as DNASTAR software. Whether an amino acid change results in a biologically active dendritic cell immunoreceptor polypeptide can readily be determined by assaying for ligand binding activity, as described for example, in the specific examples, below. Fusion Proteins Fusion proteins are useful for generating antibodies against dendritic cell immunoreceptor polypeptide amino acid sequences and for use in various assay systems. For example, fusion proteins can be used to identify proteins which interact with portions of a dendritic cell immunoreceptor polypeptide. Protein affinity chromatography or library- based assays for protein-protein interactions, such as the yeast two-hybrid or phage display systems, can be used for this purpose. Such methods are well known in the art and also can be used as drug screens. A dendritic cell immunoreceptor polypeptide fusion protein comprises two poly- peptide segments fused together by means of a peptide bond. The first polypeptide segment comprises at least 6, 10, 15, 20, 25, 50, 75, 100, 125, or 134 contiguous amino acids of SEQ ID NO: 2 or of a biologically active variant, such as those described above. A dendritic cell immunoreceptor polypeptide fusion protein comprises two polypeptide segments fused together by means of a peptide bond. The first polypeptide segment comprises at least 6, 10, 15, 20, 25, 50, 75, 100, 125, or 148 contiguous amino acids of SEQ ID NO: 15 or of a biologically active variant, such as those described above. The first polypeptide segment also can comprise full- length dendritic cell immunoreceptor protein. The second polypeptide segment can be a full-length protein or a protein fragment. Proteins commonly used in fusion protein construction include β-galactosidase, β- glucuronidase, green fluorescent protein (GFP), autofluorescent proteins, including blue fluorescent protein (BFP), glutathione-S-transferase (GST), luciferase, horseradish peroxidase (HRP), and chloramphenicol acetyltransferase (CAT). Additionally, epitope tags are used in fusion protein constructions, including histidine (His) tags, FLAG tags, influenza hemagglutinin (HA) tags, Myc tags, VSV- G tags, and thioredoxin (Trx) tags, Other fusion constructions can include maltose binding protein (MBP), S-tag, Lex a DNA binding domain (DBD) fusions, GAL4 DNA binding domain fusions, and herpes simplex virus (HSV) BP16 protein fusions. A fusion protein also can be engineered to contain a cleavage site located between the dendritic cell immunoreceptor polypeptide-encoding sequence and the heterologous protein sequence, so that the dendritic cell immunoreceptor polypeptide can be cleaved and purified away from the heterologous moiety. A fusion protein can be synthesized chemically, as is known in the art. Preferably, a fusion protein is produced by covalently linking two polypeptide segments or by standard procedures in the art of molecular biology. Recombinant DNA methods can be used to prepare fusion proteins, for example, by making a DNA construct which comprises coding sequences selected from the complement of SEQ ID NOS: 1 and 14 in proper reading frame with nucleotides encoding the second polypeptide segment and expressing the DNA construct in a host cell, as is known in the art. Many kits for constructing fusion proteins are available from companies such as Promega Corporation (Madison, WI), Stratagene (La Jolla, CA), CLONTECH (Mountain View, CA), Santa Cruz Biotechnology (Santa Cruz, CA), MBL International Corporation (MIC; Watertown, MA), and Quantum Biotechnologies (Montreal, Canada; 1-888-DNA-KITS). Identification of Species Homologs Species homologs of human dendritic cell immunoreceptor polypeptide can be obtained using dendritic cell immunoreceptor polypeptide polynucleotides (described below) to make suitable probes or primers for screening cDNA expression libraries from other species, such as mice, monkeys, or yeast, identifying cDNAs which encode homologs of dendritic cell immunoreceptor polypeptide, and expressing the cDNAs as is known in the art. Polynucleotides A dendritic cell immunoreceptor polynucleotide can be single- or double-stranded and comprises a coding sequence or the complement of a coding sequence for a dendritic cell immunoreceptor polypeptide. A partial coding sequence for human dendritic cell immunoreceptor is shown in SEQ ID NOS: 1 and 14. Degenerate nucleotide sequences encoding human dendritic cell immunoreceptor polypeptides, as well as homologous nucleotide sequences which are at least about 50, 55, 60, 65, 70, preferably about 75, 90, 96, or 98% identical to the nucleotide sequence shown in SEQ ID NOS: 1 and 14 or its complement also are dendritic cell immunoreceptor polynucleotides. Percent sequence identity between the sequences of two polynucleotides is determined using computer programs such as ALIGN which employ the FASTA algorithm, using an affine gap search with a gap open penalty of -12 and a gap extension penalty of -2. Complementary DNA (cDNA) molecules, species homologs, and variants of dendritic cell immunoreceptor polynucleotides which encode biologically active dendritic cell immunoreceptor polypeptides also are dendritic cell immunoreceptor polynucleotides. Identification of Polynucleotide Variants and Homologs Variants and homologs of the dendritic cell immunoreceptor polynucleotides described above also are dendritic cell immunoreceptor polynucleotides. Typically, homologous dendritic cell immunoreceptor polynucleotide sequences can be identified by hybridization of candidate polynucleotides to known dendritic cell immunoreceptor polynucleotides under stringent conditions, as is known in the art. For example, using the following wash conditions-2X SSC (0.3 M NaCl, 0.03 M sodium citrate, pH 7.0), 0.1% SDS, room temperature twice, 30 minutes each; then 2X SSC, 0.1% SDS, 50°C once, 30 minutes; then 2X SSC, room temperature twice, 10 minutes each— homologous sequences can be identified which contain at most about 25-30%) basepair mismatches. More preferably, homologous nucleic acid strands contain 15-25% basepair mismatches, even more preferably 5-15% basepair mismatches. Species homologs of the dendritic cell immunoreceptor polynucleotides disclosed herein also can be identified by making suitable probes or primers and screening cDNA expression libraries from other species, such as mice, monkeys, or yeast. Human variants of dendritic cell immunoreceptor polynucleotides can be identified, for example, by screening human cDNA expression libraries. It is well known that the T m of a double- stranded DNA decreases by 1-1.5°C with every 1% decrease in homology (Bonner et al., J. Mol. Biol. 81, 123 (1973). Variants of human dendritic cell immunoreceptor polynucleotides or dendritic cell immunoreceptor poly- nucleotides of other species can therefore be identified by hybridizing a putative homologous dendritic cell immunoreceptor polynucleotide with a polynucleotide having a nucleotide sequence of SEQ ID NOS: 1 and 14 or the complement thereof to form a test hybrid. The melting temperature of the test hybrid is compared with the melting temperature of a hybrid comprising polynucleotides having perfectly complementary nucleotide sequences, and the number or percent of basepair mismatches within the test hybrid is calculated. Nucleotide sequences which hybridize to dendritic cell immunoreceptor polynucleo- tides or their complements following stringent hybridization and/or wash conditions also are dendritic cell immunoreceptor polynucleotides. Stringent wash conditions are well known and understood in the art and are disclosed, for example, in Sambrook et al., MOLECULAR CLONING: A LABORATORY MANUAL, 2d ed., 1989, at pages 9.50-9.51. Typically, for stringent hybridization conditions a combination of temperature and salt concentration should be chosen that is approximately 12-20°C below the calculated T m of the hybrid under study. The T m of a hybrid between a dendritic cell immunoreceptor polynucleotide having a nucleotide sequence shown in SEQ ID NOS: 1 and 14 or the complement thereof and a polynucleotide sequence which is at least about 50, preferably about 75, 90, 96, or 98%> identical to one of those nucleotide sequences can be calculated, for example, using the equation of Bolton and McCarthy, Proc. Natl. Acad Sci. U.S.A. 48, 1390 (1962): T m = 81.5°C - 16.6(log 10 [Na + ]) + 0.41(%G + C) - 0.63(%formamide) - 600/0, where / = the length of the hybrid in basepairs. Stringent wash conditions include, for example, 4X SSC at 65°C, or 50% formamide, 4X SSC at 42°C, or 0.5X SSC, 0.1 % SDS at 65°C. Highly stringent wash conditions include, for example, 0.2X SSC at 65°C. Preparation of Polynucleotides A dendritic cell immunoreceptor polynucleotide can be isolated free of other cellular components such as membrane components, proteins, and lipids. Polynucleotides can be made by a cell and isolated using standard nucleic acid purification techniques, or synthesized using an amplification technique, such as the polymerase chain reaction (PCR), or by using an automatic synthesizer. Methods for isolating polynucleotides are routine and are known in the art. Any such technique for obtaining a polynucleotide can be used to obtain isolated dendritic cell immuno- receptor polynucleotides. For example, restriction receptors and probes can be used to isolate polynucleotide fragments which comprises dendritic cell immunoreceptor nucleotide sequences. Isolated polynucleotides are in preparations which are free or at least 70, 80, or 90% free of other molecules. Human dendritic cell immunoreceptor cDNA molecules can be made with standard molecular biology techniques, using dendritic cell immunoreceptor rαRNA as a template. Human dendritic cell immunoreceptor cDNA molecules can thereafter be replicated using molecular biology techniques known in the art and disclosed in manuals such as Sambrook et al. (1989). An amplification technique, such as PCR, can be used to obtain additional copies of polynucleotides of the invention, using either human genomic DNA or cDNA as a template. Alternatively, synthetic chemistry techniques can be used to synthesizes dendritic cell immunoreceptor polynucleotides. The degeneracy of the genetic code allows alternate nucleotide sequences to be synthesized which will encode a dendritic cell immunoreceptor polypeptide having, for example, an amino acid sequence shown in SEQ ID NOS: 2 and 15 or a biologically active variant thereof. Extending Polynucleotides The partial sequence disclosed herein can be used to identify the corresponding full length gene from which it was derived. The partial sequences can be nick-translated or end-labeled with 32 P using polynucleotide kinase using labeling methods known to those with skill in the art (BASIC METHODS IN MOLECULAR BIOLOGY, Davis et al, eds., Elsevier Press, N. ., 1986). A lambda library prepared from human tissue can be directly screened with the labeled sequences of interest or the library can be converted en masse to pBluescript (Stratagene Cloning Systems, La Jolla, Calif. 92037) to facilitate bacterial colony screening (see Sambrook et al., MOLECULAR CLONING: A LABORATORY MANUAL, Cold Spring Harbor Laboratory Press (1989, pg. 1.20). Both methods are well known in the art. Briefly,- filters with bacterial colonies containing the library in pBluescript or bacterial lawns containing lambda plaques are denatured, and the DNA is fixed to the filters. The filters are hybridized with the labeled probe using hybridization conditions described by Davis et al., 1986. The partial sequences, cloned into lambda or pBluescript, can be used as positive controls to assess background binding and to adjust the hybridization and washing stringencies necessary for accurate clone identification. The resulting autoradio- grams are compared to duplicate plates of colonies or plaques; each exposed spot corresponds to a positive colony or plaque. The colonies or plaques are selected, expanded and the DNA is isolated from the colonies for further analysis and sequencing. Positive cDNA clones are analyzed to determine the amount of additional sequence they contain using PCR with one primer from the partial sequence and the other primer from the vector. Clones with a larger vector-insert PCR product than the original partial sequence are analyzed by restriction digestion and DNA sequencing to determine whether they contain an insert of the same size or similar as the mRNA size determined from Northern blot Analysis. Once one or more overlapping cDNA clones are identified, the complete sequence of the clones can be determined , for example after exonuclease III digestion (McCombie et al., Methods 3, 33-40, 1991). A series of deletion clones are generated, each of which is sequenced. The resulting overlapping sequences are assembled into a single contiguous sequence of high redundancy (usually three to five overlapping sequences at each nucleotide position), resulting in a highly accurate final sequence. Various PCR-based methods can be used to extend the nucleic acid sequences disclosed herein to detect upstream sequences such as promoters and regulatory elements. For example, restriction-site PCR uses universal primers to retrieve unknown sequence adjacent to a known locus (Sarkar, PCR Methods Applic. 2, 318- 322, 1993). Genomic DNA is first amplified in the presence of a primer to a linker sequence and a primer specific to the known region. The amplified sequences are then subjected to a second round of PCR with the same linker primer and another specific primer internal to the first one. Products of each round of PCR are transcribed with an appropriate RNA polymerase and sequenced using reverse transcriptase. Inverse PCR also can be used to amplify or extend sequences using divergent primers based on a known region (Triglia et al., Nucleic Acids Res. 16, 8186, 1988). Primers can be designed using commercially available software, such as OLIGO 4.06 Primer Analysis software (National Biosciences Inc., Plymouth, Minn.), to be 22-30 nucleotides in length, to have a GC content of 50% or more, and to anneal to the target sequence at temperatures about 68-72°C. The method uses several restriction receptors to generate a suitable fragment in the known region of a gene. The fragment is then circularized by intramolecular ligation and used as a PCR template. Another method which can be used is capture PCR, which involves PCR amplification of DNA fragments adjacent to a known sequence in human and yeast artificial chromosome DNA (Lagerstrom et al., PCR Methods Applic. 1, 111-1 19, 1991). In this method, multiple restriction receptor digestions and ligations also can be used to place an engineered double-stranded sequence into an unknown fragment of the DNA molecule before performing PCR. Another method which can be used to retrieve unknown sequences is that of Parker et al., Nucleic Acids Res. 19, 3055-3060, 1991). Additionally, PCR, nested primers, and PROMOTERFINDER libraries (CLONTECH, Palo Alto, Calif.) can be used to walk genomic DNA (CLONTECH, Palo Alto, Calif). This process avoids the need to screen libraries and is useful in finding intron/exon junctions. When screening for full-length cDNAs, it is preferable to use libraries that have been size-selected to include larger cDNAs. Randomly-primed libraries are preferable, in that they will contain more sequences which contain the 5' regions of genes. Use of a randomly primed library may be especially preferable for situations in which an oligo d(T) library does not yield a full-length cDNA. Genomic libraries can be useful for extension of sequence into 5' non-transcribed regulatory regions. Commercially available capillary electrophoresis systems can be used to analyze the size or confirm the nucleotide sequence of PCR or sequencing products. For example, capillary sequencing can employ flowable polymers for electrophoretic separation, four different fluorescent dyes (one for each nucleotide) which are laser activated, and detection of the emitted wavelengths by a charge coupled device camera. Output/light intensity can be converted to electrical signal using appropriate software (e.g. GENOTYPER and Sequence NAVIGATOR, Perkin Elmer), and the entire process from loading of samples to computer analysis and electronic data display can be computer controlled. Capillary electrophoresis is especially preferable for the sequencing of small pieces of DNA which might be present in limited amounts in a particular sample. Obtaining Polypeptides Human dendritic cell immunoreceptor polypeptides can be obtained, for example, by purification from human cells, by expression of dendritic cell immunoreceptor polynucleotides, or by direct chemical synthesis. Protein Purification Human dendritic cell immunoreceptor polypeptides can be purified from any cell which expresses the receptor, including host cells which have been transfected with dendritic cell immunoreceptor expression constructs. A purified dendritic cell immunoreceptor polypeptide is separated from other compounds which normally associate with the dendritic cell immunoreceptor polypeptide in the cell, such as certain proteins, carbohydrates, or lipids, using methods well-known in the art. Such methods include, but are not limited to, size exclusion chromatography, ammonium sulfate fractionation, ion exchange chromatography, affinity chromatography, and preparative gel electrophoresis. A preparation of purified dendritic cell immunoreceptor polypeptides is at least 80% pure; preferably, the preparations are 90%, 95%, or 99%> pure. Purity of the preparations can be assessed by any means known in the art, such as SDS-polyacrylamide gel electrophoresis. Expression of Polynucleotides To express a dendritic cell immunoreceptor polynucleotide, the polynucleotide can be inserted into an expression vector which contains the necessary elements for the transcription and translation of the inserted coding sequence. Methods which are well known to those skilled in the art can be used to construct expression vectors containing sequences encoding dendritic cell immunoreceptor polypeptides and appropriate transcriptional and translational control elements. These methods include in vitro recombinant DNA techniques, synthetic techniques, and in vivo genetic recombination. Such techniques are described, for example, in Sambrook et al. (1989) and in Ausubel et al., CURRENT PROTOCOLS IN MOLECULAR BIOLOGY, John Wiley & Sons, New York, N.Y., 1989. A variety of expression vector/host systems can be utilized to contain and express sequences encoding a dendritic cell immunoreceptor polypeptide. These include, but are not limited to, microorganisms, such as bacteria transformed with recombinant bacteriophage, plasmid, or cosmid DNA expression vectors; yeast transformed with yeast expression vectors, insect cell systems infected with virus expression vectors (e.g., baculovirus), plant cell systems transformed with virus expression vectors (e.g., cauliflower mosaic virus, CaMV; tobacco mosaic virus, TMV) or with bacterial expression vectors (e.g., Ti or pBR322 plasmids), or animal cell systems. The control elements or regulatory sequences are those non-translated regions of the vector — enhancers, promoters, 5' and 3' untranslated regions -- which interact with host cellular proteins to carry out transcription and translation. Such elements can vary in their strength and specificity. Depending on the vector system and host utilized, any number of suitable transcription and translation elements, including constitutive and inducible promoters, can be used. For example, when cloning in bacterial systems, inducible promoters such as the hybrid lacZ promoter of the BLUESCRIPT phagemid (Stratagene, LaJolla, Calif.) or pSPORTl plasmid (Life Technologies) and the like can be used. The baculovirus polyhedrin promoter can be used in insect cells. Promoters or enhancers derived from the genomes of plant cells (e.g., heat shock, RUBISCO, and storage protein genes) or from plant viruses (e.g., viral promoters or leader sequences) can be cloned into the vector. In mammalian cell systems, promoters from mammalian genes or from mammalian viruses are preferable. If it is necessary to generate a cell line that contains multiple copies of a nucleotide sequence encoding a dendritic cell immunoreceptor polypeptide, vectors based on SV40 or EBV can be used with an appropriate selectable marker. Bacterial and Yeast Expression Systems In bacterial systems, a number of expression vectors can be selected depending upon the use intended for the dendritic cell immunoreceptor polypeptide. For example, when a large quantity of a dendritic cell immunoreceptor polypeptide is needed for the induction of antibodies, vectors which direct high level expression of fusion proteins that are readily purified can be used. Such vectors include, but are not limited to, multifunctional E. coli cloning and expression vectors such as BLUESCRIPT (Stratagene). In a BLUESCRIPT vector, a sequence encoding the dendritic cell immunoreceptor polypeptide can be ligated into the vector in frame with sequences for the amino-terminal Met and the subsequent 7 residues of β- galactosidase so that a hybrid protein is produced. pIN vectors (Van Heeke & Schuster, J. Biol. Chem. 264, 5503-5509, 1989) - or pGEX vectors (Promega, Madison, Wis.) also can 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 adsorption to glutathione-agarose beads followed by elution in the presence of free glutathione, Proteins made in such systems can be designed to include heparin, thrombin, or factor Xa protease cleavage sites so that the cloned polypeptide of interest can be released from the GST moiety at will. In the yeast Saccharomyces cerevisiae, a number of vectors containing constitutive or inducible promoters such as alpha factor, alcohol oxidase, and PGH can be used. For reviews, see Ausubel et al. (1989) and Grant et al., Methods Enzymol. 153, 516- 544, 1987. Plant and Insect Expression Systems If plant expression vectors are used, the expression of sequences encoding dendritic cell immunoreceptor polypeptides can be driven by any of a number of promoters. For example, viral promoters such as the 35S and 19S promoters of CaMV can be used alone or in combination with the omega leader sequence from TMV (Takamatsu, EMBO J. 6, 307-31 1, 1987). Alternatively, plant promoters such as the small subunit of RUBISCO or heat shock promoters can be used (Coruzzi et al., EMBO J. 3, 1671-1680, 1984; Broglie et al., Science 224, 838-843, 1984; Winter et al., Results Pr obi. Cell Differ, 17, 85-105, 1991). These constructs can be introduced into plant cells by direct DNA transformation or by pathogen-mediated transfection. Such techniques are described in a number of generally available reviews (e.g., Hobbs or Murray, in MCGRAW HILL YEARBOOK OF SCIENCE AND TECHNOLOGY, McGraw Hill, New York, N.Y., pp. 191-196, 1992). An insect system also can be used to express a dendritic cell immunoreceptor polypeptide. For example, in one such system Autographa californica nuclear poly- hedrosis virus (AcNPV) is used as a vector to express foreign genes in Spodoptera frugiperda cells or in Trichophisia larvae. Sequences encoding dendritic cell immunoreceptor polypeptides can be cloned into a non-essential region of the virus, such as the polyhedrin gene, and placed under control of the polyhedrin promoter. Successful insertion of dendritic cell immunoreceptor polypeptides will render the polyhedrin gene inactive and produce recombinant virus lacking coat protein. The recombinant viruses can then be used to infect S. frugiperda cells or Trichoplusia larvae in which dendritic cell immunoreceptor polypeptides can be expressed (Engelhard et al, Proc. Nat. Aca Sci. 91, 3224-3227, 1994). Mammalian Expression Systems A number of viral-based expression systems can be used to express dendritic cell immunoreceptor polypeptides in mammalian host cells. For example, if an adeno- virus is used as an expression vector, sequences encoding dendritic cell immunoreceptor polypeptides can be ligated into an adenovirus transcription/translation complex comprising the late promoter and tripartite leader sequence. Insertion in a non-essential El or E3 region of the viral genome can be used to obtain a viable virus which is capable of expressing a dendritic cell immunoreceptor polypeptide in infected host cells (Logan & Shenk, Proc. Natl. Acad. Sci. 81, 3655-3659, 1984). If desired, transcription enhancers, such as the Rous sarcoma virus (RSV) enhancer, can be used to increase expression in mammalian host cells. Human artificial chromosomes (HACs) also can be used to deliver larger fragments of DNA than can be contained and expressed in a plasmid. HACs of 6M to 10M are constructed and delivered to cells via conventional delivery methods (e.g., liposomes, polycationic amino polymers, or vesicles). Specific initiation signals also can be used to achieve more efficient translation of sequences encoding dendritic cell immunoreceptor polypeptides. Such signals include the ATG initiation codon and adjacent sequences. In cases where sequences encoding a dendritic cell immunoreceptor polypeptide, its initiation codon, and upstream sequences are inserted into the appropriate expression vector, no additional transcriptional or translational control signals may be needed. However, in cases where only coding sequence, or a fragment thereof, is inserted, exogenous translational control signals (including the ATG initiation codon) should be provided. The initiation codon should be in the correct reading frame to ensure translation of the entire insert. Exogenous translational elements and initiation codons can be of various origins, both natural and synthetic. The efficiency of expression can be enhanced by the inclusion of enhancers which are appropriate for the particular cell system which is used (see Scharf e/ al, Results Probl. Cell Differ. 20, 125-162, 1994). Host Cells A host cell strain can be chosen for its ability to modulate the expression of the inserted sequences or to process the expressed dendritic cell immunoreceptor polypeptide in the desired fashion. Such modifications of the polypeptide include, but are not limited to, acetylation, carboxylation, glycosylation, phosphorylation, lipidation, and acylation, Post-translational processing which cleaves a "prepro" form of the polypeptide also can be used to facilitate correct insertion, folding and/or function. Different host cells which have specific cellular machinery and characteristic mechanisms for post-translational activities (e.g., CHO, HeLa, MDCK, HEK293, and WI38), are available from the American Type Culture Collection (ATCC; 10801 University Boulevard, Manassas, VA 20110-2209) and can be chosen to ensure the correct modification and processing of the foreign protein. Stable expression is preferred for long-term, high-yield production of recombinant proteins. For example, cell lines which stably express dendritic cell immunoreceptor polypeptides can be transformed using expression vectors which can contain viral origins of replication and/or endogenous expression elements and a selectable marker gene on the same or on a separate vector. Following the introduction of the vector, cells can be allowed to grow for 1-2 days in an enriched medium before they are switched to a selective medium. The purpose of the selectable marker is to confer resistance to selection, and its presence allows growth and recovery of cells which successfully express the introduced dendritic cell immunoreceptor sequences. Resistant clones of stably transformed cells can be proliferated using tissue culture techniques appropriate to the cell type. See, for example, ANIMAL CELL CULTURE, R.I. Freshney, ed., 1986. Any number of selection systems can be used to recover transformed cell lines. These include, but are not limited to, the herpes simplex virus thymidine kinase (Wigler et al, Cell 11, 223-32, 1977) and adenine phosphoribosyltransferase (Lowy et al, Cell 22, 817-23, 1980) genes which can be employed in tk ~ or aprf cells, respectively, Also, antimetabolite, antibiotic, or herbicide resistance can be used as the basis for selection. For example, dhfr confers resistance to methotrexate (Wigler et al, Proc. NatL Acad. Set 77, 3567-70, 1980), npt confers resistance to the aminoglycosides, neomycin and G-418 (Colbere-Garapin et al, Mol. Biol 150, 1- 14, 1981), and als and pat confer resistance to chlorsulfuron and phosphinotricin acetyltransferase, respectively (Murray, 1992, supra). Additional selectable genes have been described. For example, trpB allows cells to utilize indole in place of tryptophan, or hisD, which allows cells to utilize histinol in place of histidine (Hartman & Mulligan, Proc, Nai Acad. Sci. 85, 8047-51, 1988). Visible markers such as anthocyanins, β-glucuronidase and its substrate GUS, and luciferase and its substrate luciferin, can be used to identify transformants and to quantify the amount of transient or stable protein expression attributable to a specific vector system (Rhodes et al, Methods Mol. Biol. 55, 121-131, 1995). Detecting Expression Although the presence of marker gene expression suggests that the dendritic cell immunoreceptor polynucleotide is also present, its presence and expression may need to be confirmed. For example, if a sequence encoding a dendritic cell immuno- receptor polypeptide is inserted within a marker gene sequence, transformed cells containing sequences which encode a dendritic cell immunoreceptor polypeptide can be identified by the absence of marker gene function. Alternatively, a marker gene can be placed in tandem with a sequence encoding a dendritic cell immunoreceptor polypeptide under the control of a single promoter. Expression of the marker gene in response to induction or selection usually indicates expression of the dendritic cell immunoreceptor polynucleotide. Alternatively, host cells which contain a dendritic cell immunoreceptor polynucleotide and which express a dendritic cell immunoreceptor polypeptide can be identified by a variety of procedures known to those of skill in the art. These procedures include, but are not limited to, DNA-DNA or DNA-RNA hybridizations and protein bioassay or immunoassay techniques which include membrane, solution, or chip- based technologies for the detection and/or quantification of nucleic acid or protein. For example, the presence of a polynucleotide sequence encoding a dendritic cell immunoreceptor polypeptide can be detected by DNA-DNA or DNA-RNA hybridization or amplification using probes or fragments or fragments of poly- nucleotides encoding a dendritic cell immunoreceptor polypeptide. Nucleic acid amplification-based assays involve the use of oligonucleotides selected from sequences encoding a dendritic cell immunoreceptor polypeptide to detect trans- formants which contain a dendritic cell immunoreceptor polynucleotide. A variety of protocols for detecting and measuring the expression of a dendritic cell immunoreceptor polypeptide, using either polyclonal or monoclonal antibodies specific for the polypeptide, are known in the art. Examples include receptor-linked immunosorbent assay (ELISA), radioimmunoassay (RIA), and fluorescence activated cell sorting (FACS). A two-site, monoclonal-based immunoassay using monoclonal antibodies reactive to two non-interfering epitopes on a dendritic cell immunoreceptor polypeptide can be used, or a competitive binding assay can be employed. These and other assays are described in Hampton et al, SEROLOGICAL METHODS: A LABORATORY MANUAL, APS Press, St. Paul, Minn., -1990) and Maddox et al, J. Exp. Med. 158, 1211-1216, 1983). A wide variety of labels and conjugation techniques are known by those skilled in the art and can be used in various nucleic acid and amino acid assays. Means for producing labeled hybridization or PCR probes for detecting sequences related to polynucleotides encoding dendritic cell immunoreceptor polypeptides include oligolabeling, nick translation, end-labeling, or PCR amplification using a labeled nucleotide. Alternatively, sequences encoding a dendritic cell immunoreceptor polypeptide can be cloned into a vector for the production of an mRNA probe. Such vectors are known in the art, are commercially available, and can be used to synthesize RNA probes in vitro by addition of labeled nucleotides and an appropriate RNA polymerase such as T7, T3, or SP6. These procedures can be conducted using a variety of commercially available kits (Amersham Pharmacia Biotech, Promega, and US Biochemical). Suitable reporter molecules or labels which can be used for ease of detection include radionuclides, receptors, and fluorescent, chemilu- minescent, or chromogenic agents, as well as substrates, cofactors, inhibitors, magnetic particles, and the like. Expression and Purification of Polypeptides Host cells transformed with nucleotide sequences encoding a dendritic cell immuno- receptor polypeptide can be cultured under conditions suitable for the expression and recovery of the protein from cell culture. The polypeptide produced by a transformed cell can be secreted or contained intracellularly depending on the sequence and/or the vector used. As will be understood by those of skill in the art, expression vectors containing polynucleotides which encode dendritic cell immunoreceptor poly- peptides can be designed to contain signal sequences which direct secretion of soluble dendritic cell immunoreceptor polypeptides through a prokaryotic or eukaryotic cell membrane or which direct the membrane insertion of membrane- bound dendritic cell immunoreceptor polypeptide. As discussed above, other constructions can be used to join a sequence encoding a dendritic cell immunoreceptor polypeptide to a nucleotide sequence encoding a polypeptide domain which will facilitate purification of soluble proteins. Such purification facilitating domains include, but are not limited to, metal chelating peptides such as histidine-tryptophan modules that allow purification on immobilized metals, protein A domains that allow purification on immobilized immunoglobulin, and the domain utilized in the FLAGS extension/affinity purification system (Immunex Corp., Seattle, Wash.). Inclusion of cleavable linker sequences such as those specific for Factor Xa or enterokinase (Invitrogen, San Diego, CA) between the purification domain and the dendritic cell immunoreceptor polypeptide also can be used to facilitate purification. One such expression vector provides for expression of a fusion protein containing a dendritic cell immunoreceptor polypeptide and 6 histidine residues preceding a thioredoxin or an enterokinase cleavage site. The histidine residues facilitate purification by IMAC (immobilized metal ion affinity chromatography, as described in Porath et al, Prot Exp. Purif. 3, 263-281, 1992), while the enterokinase cleavage site provides a means for purifying the dendritic cell immunoreceptor polypeptide from the fusion protein. Vectors which contain fusion proteins are disclosed in I roll et al, DNA Cell Biol, 12, 441-453, 1993. Chemical Synthesis Sequences encoding a dendritic cell immunoreceptor polypeptide can be synthesized, in whole or in part, using chemical methods well known in the art (see Caruthers et al, Nucl Acids Res. Symp. Ser. 215-223, 1980; Horn et al. Niicl Acids Res. Symp. Ser. 225-232, 1980). Alternatively, a dendritic cell immunoreceptor polypeptide itself can be produced using chemical methods to synthesize its amino acid sequence, such as by direct peptide synthesis using solid-phase techniques (Merrifield, J, Am. Chem. Soc. 85, 2149-2154, 1963; Roberge et al, Science 269, 202-204, 1995). Protein synthesis can be performed using manual techniques or by automation. Automated synthesis can be achieved, for example, using Applied Biosystems 431 A Peptide Synthesizer (Perkin Elmer). Optionally, fragments of dendritic cell immunoreceptor polypeptides can be separately synthesized and combined using chemical methods to produce a full-length molecule. The newly synthesized peptide can be substantially purified by preparative high performance liquid chromatography (e.g., Creighton, PROTEINS: STRUCTURES AND MOLECULAR PRINCIPLES, WH Freeman and Co., New York, N.Y., 1983). The composition of a synthetic dendritic cell immunoreceptor polypeptide can be confirmed by amino acid analysis or sequencing (e.g., the Edman degradation procedure; see Creighton, supra). Additionally, any portion of the amino acid sequence of the dendritic cell immunoreceptor polypeptide can be altered during direct synthesis and/or combined using chemical methods with sequences from other proteins to produce a variant polypeptide or a fusion protein. Production of Altered Polypeptides As will be understood by those of skill in the art, it may be advantageous to produce dendritic cell immunoreceptor polypeptide-encoding nucleotide sequences possessing non-naturally occurring codons. For example, codons preferred by a particular prokaryotic or eukaryotic host can be selected to increase the rate of protein expression or to produce an RNA transcript having desirable properties, such as a half-life which is longer than that of a transcript generated from the naturally occurring sequence. The nucleotide sequences disclosed herein can be engineered using methods generally known in the art to alter dendritic cell immunoreceptor polypeptide- encoding sequences for a variety of reasons, including but not limited to, alterations which modify the cloning, processing, and/or expression of the polypeptide or rn -NA product. DNA shuffling by random fragmentation and PCR reassembly of gene fragments and synthetic oligonucleotides can be used to engineer the nucleotide sequences. For example, site-directed mutagenesis can be used to insert new restriction sites, alter glycosylation patterns, change codon preference, produce splice variants, introduce mutations, and so forth. Antibodies Any type of antibody known in the art can be. generated to bind specifically to an epitope of a dendritic cell immunoreceptor polypeptide. "Antibody" as used herein includes intact immunoglobulin molecules, as well as fragments thereof, such as Fab, F(ab') 2 , and Fv, which are capable of binding an epitope of a dendritic cell immunoreceptor polypeptide. Typically, at least 6, 8, 10, or 12 contiguous amino acids are required to form an epitope. However, epitopes which involve noncontiguous amino acids may require more, e.g., at least 15, 25, or 50 amino acids. An antibody which specifically binds to an epitope of a dendritic cell immunoreceptor polypeptide can be used therapeutically, as well as in immunochemical assays, such as Western blots, ELISAs, radioimmunoassays, immunohistochemical assays, immunoprecipitations, or other immunochemical assays known in the art. Various immunoassays can be used to identify antibodies having the desired specificity. Numerous protocols for competitive binding or immunoradiometric assays are well known in the art. Such immunoassays typically involve the measurement of complex formation between an immunogen and an antibody which specifically binds to the immunogen. Typically, an antibody which specifically binds to a dendritic cell immunoreceptor polypeptide provides a detection signal at least 5-, 10-, or 20-fold higher than a detection signal provided with other proteins when used in an immunochemical assay. Preferably, antibodies which specifically bind to dendritic cell immuno- receptor polypeptides do not detect other proteins in immunochemical assays and can immunoprecipitate a dendritic cell immunoreceptor polypeptide from solution. Human dendritic cell immunoreceptor polypeptides can be used to immunize a mammal, such as a mouse, rat, rabbit, guinea pig, monkey, or human, to produce polyclonal antibodies. If desired, a dendritic cell immunoreceptor polypeptide can be conjugated to a carrier protein, such as bovine serum albumin, thyroglobulin, and keyhole limpet hemocyanin. Depending on the host species, various adjuvants can be used to increase the immunological response.. Such adjuvants include, but are not limited to, Freund's adjuvant, mineral gels (e.g., aluminum hydroxide), and surface active substances (e.g. lysolecithin, pluronic polyols, polyanions, peptides, oil emulsions, keyhole limpet hemocyanin, and dinitrophenol). Among adjuvants used in humans, BCG (bacilli Calmette-Guerin) and Corynebacterium parviim are especially useful. Monoclonal antibodies which specifically bind to a dendritic cell immunoreceptor polypeptide can be prepared using any technique which provides for the production of antibody molecules by continuous cell lines in culture. These techniques include, but are not limited to, the hybridoma technique, the human B-cell hybridoma technique, and the EBV-hybridoma technique (Kohler et al, Nature 256, 495-497, 1985; Kozbor et al, J. Immunol. Methods 81, 31-42, 1985; Cote et al, Proc. Natl. Acad. Sci. 80, 2026-2030, 1983; Cole et al, Mol. Cell Biol. 62, 109-120, 1984). In addition, techniques developed for the production of "chimeric antibodies," the splicing of mouse antibody genes to human antibody genes to obtain a molecule with appropriate antigen specificity and biological activity, can be used (Morrison et al, Proc. Natl. Acad. Sci. 81, 6851-6855, 1984; Neuberger et al, Nature 312, 604-608, 1984; Takeda et al, Nature 314, 452-454, 1985). Monoclonal and other antibodies also can be "humanized" to prevent a patient from mounting an immune response against the antibody when it is used therapeutically. Such antibodies may be sufficiently similar in sequence to human antibodies to be used directly in therapy or may require alteration of a few key residues. Sequence differences between rodent antibodies and human sequences can be minimized by replacing residues which differ from those in the human sequences by site directed mutagenesis of individual residues or by grating of entire complementarity determining regions. Alternatively, humanized antibodies can be produced using recombinant methods, as described in GB2188638B. Antibodies which specifically bind to a dendritic cell immunoreceptor polypeptide can contain antigen binding sites which are either partially or fully humanized, as disclosed in U.S. 5,565,332. Alternatively, techniques described for the production of single chain antibodies can be adapted using methods known in the art to produce single chain antibodies which specifically bind to dendritic cell immunoreceptor polypeptides. Antibodies with related specificity, but of distinct idiotypic composition, can be generated by chain shuffling from random combinatorial immunoglobin libraries (Burton, Proc. Natl. Acad. Sci. 88, 11120-23, 1991). Single-chain antibodies also can be constructed using a DNA amplification method, such as PCR, using hybridoma cDNA as a template (Thirion et al, 1996, Eur. J. Cancer Prev. 5, 507-1 1). Single-chain antibodies can be mono- or bispecific, and can be bivalent or tetravalent. Construction of tetravalent, bispecific single-chain antibodies is taught, for example, in Coloma & Morrison, 1997, Nat. Biotechnol 15, 159-63. Construction of bivalent, bispecific single-chain antibodies is taught in Mallender & Voss, 1994, J. Biol. Chem. 269, 199-206. A nucleotide sequence encoding a single-chain antibody can be constructed using manual or automated nucleotide synthesis, cloned into an expression construct using standard recombinant DNA methods, and introduced into a cell to express the coding sequence, as described below. Alternatively, single-chain antibodies can be produced directly using, for example, filamentous phage technology (Verhaar et al, 1995, Int. J Cancer 61, 497-501; Nicholls et al, 1993, J Immunol. Meth. 165, 81- 91). Antibodies which specifically bind to dendritic cell immunoreceptor polypeptides also can be produced by inducing in vivo production in the lymphocyte population or by screening immunoglobulin libraries or panels of highly specific binding reagents as disclosed in the literature (Orlandi et al, Proc. Natl. Acad. Sci. 86, 3833-3837, 1989; Winter et al, Nature 349, 293-299, 1991). Other types of antibodies can be constructed and used therapeutically in methods of the invention. For example, chimeric antibodies can be constructed as disclosed in WO 93/03151. Binding proteins which are derived from immunoglobulins and which are multivalent and multispecific, such as the "diabodies" described in WO 94/13804, also can be prepared. Antibodies according to the invention can be purified by methods well known in the art. For example, antibodies can be affinity purified by passage over a column to which a dendritic cell immunoreceptor polypeptide is bound. The bound antibodies can then be eluted from the column using a buffer with a high salt concentration. Antisense Oligonucleotides Antisense oligonucleotides are nucleotide sequences which are complementary to a specific DNA or RNA sequence. Once introduced into a cell, the complementary nucleotides combine with natural sequences produced by the cell to form complexes and block either transcription or translation. Preferably, an antisense oligonucleotide is at least 11 nucleotides in length, but can be at least 12, 15, 20, 25, 30, 35, 40, 45, or 50 or more nucleotides long. Longer sequences also can be used. Antisense oligonucleotide molecules can be provided in a DNA construct and introduced into a cell as described above to decrease the level of dendritic cell immunoreceptor gene products in the cell. Antisense oligonucleotides can be deoxyribonucleotides, ribonucleotides, or a combination of both. Oligonucleotides can be synthesized manually or by an automated synthesizer, by covalently linking the 5' end of one nucleotide with the 3' end of another nucleotide with non-phosphodiester internucleotide linkages such alkylphosphonates, phosphorothioates, phosphorodithioates, alkylphosphonothioates, alkylphosphonates, phosphoramidates, phosphate esters, carbamates, acetamidate, carboxymethyl esters, carbonates, and phosphate triesters. See Brown, Meth. Mol. Biol. 20, 1-8, 1994; Sonveaux, Meth. Mol. Biol. 26, 1-72, 1994; Uhlmann et al, Chem. Rev. 90, 543-583, 1990. Modifications of dendritic cell immunoreceptor gene expression can be obtained by designing antisense oligonucleotides which will form duplexes to the control, 5', or regulatory regions of the dendritic cell immunoreceptor gene. Oligonucleotides derived from the transcription initiation site, e.g., between positions -10 and +10 from the start site, are prefeπed. Similarly, inhibition can be achieved using "triple helix" base-pairing methodology. Triple helix pairing is useful because it causes inhibition of the ability of the double helix to open sufficiently for the binding of polymerases, transcription factors, or chaperons. Therapeutic advances using triplex DNA have been described in the literature (e.g., Gee et al., in Huber & Can, MOLECULAR AND IMMUNOLOGIC APPROACHES, Futura Publishing Co., Mt. Kisco, N.Y., 1994). An antisense oligonucleotide also can be designed to block translation of mRNA by preventing the transcript from binding to ribosomes. Precise complementarity is not required for successful complex formation between an antisense oligonucleotide and the complementary sequence of a dendritic cell immunoreceptor polynucleotide. Antisense oligonucleotides which comprise, for example, 2, 3, 4, or 5 or more stretches of contiguous nucleotides which are precisely complementary to a dendritic cell immunoreceptor polynucleotide, each separated by a stretch of contiguous nucleotides which are not complementary to adjacent dendritic cell immunoreceptor nucleotides, can provide sufficient targeting specificity for dendritic cell immunoreceptor mRNA, Preferably, each stretch of complementary contiguous nucleotides is at least 4, 5, 6, 7, or 8 or more nucleotides in length. Non- complementary intervening sequences are preferably 1, 2, 3, or 4 nucleotides in length. One skilled in the art can easily use the calculated melting point of an antisense-sense pair to determine the degree of mismatching which will be tolerated between a particular antisense oligonucleotide and a particular dendritic cell immunoreceptor polynucleotide sequence. Antisense oligonucleotides can be modified without affecting their ability to hybridize to a dendritic cell immunoreceptor polynucleotide. These modifications can be internal or at one or both ends of the antisense molecule. For example, inter- nucleoside phosphate linkages can be modified by adding cholesteryl or diamine moieties with varying numbers of carbon residues between the amino groups and terminal ribose. Modified bases and/or sugars, such as arabinose instead of ribose, or a 3', 5'-substituted oligonucleotide in which the 3' hydroxyl group or the 5' phosphate group are substituted, also can be employed in a modified antisense oligonucleotide. These modified oligonucleotides can be prepared by methods well known in the art. See, e.g., Agrawal et al, Trends Biotechnol 10, 152-158, 1992; Uhlmann et al, Chem. Rev. 90, 543-584, 1990; Uhlmann et al, Tetrahedron. Lett. 215, 3539-3542, 1987. Ribozymes Ribozymes are RNA molecules with catalytic activity. See, e.g., Cech, Science 236, 1532-1539; 1987; Cech, Ann. Rev. Biochem. 59, 543-568; 1990, Cech, Curr. Opin. Struct. Biol. 2, 605-609; 1992, Couture & Stinchcomb, Trends Genet. 12, 510-515, 1996. Ribozymes can be used to inhibit gene function by cleaving an RNA sequence, as is known in the art (e.g., Haseloff et al, U.S. Patent 5,641,673). The mechanism of ribozyme action involves sequence-specific hybridization of the ribozyme molecule to complementary target RNA, followed by endonucleolytic cleavage. Examples include engineered hammerhead motif -ribozyme molecules that can specifically and efficiently catalyze endonucleolytic cleavage of specific nucleotide sequences. The coding sequence of a dendritic cell immunoreceptor polynucleotide can be used to generate ribozymes which will specifically bind to mRNA transcribed from the dendritic cell immunoreceptor polynucleotide. Methods of designing and constructing ribozymes which can cleave other RNA molecules in trans in a highly sequence specific manner have been developed and described in the art (see Haseloff et al Nature 334, 585-591, 1988). For example, the cleavage activity of ribozymes can be targeted to specific RNAs by engineering a discrete "hybridization" region into the ribozyme. The hybridization region contains a sequence complementary to the target RNA and thus specifically hybridizes with the target (see, for example, Gerlach et al, EP 321,201). Specific ribozyme cleavage sites within a dendritic cell immunoreceptor RNA target can be identified by scanning the target molecule for ribozyme cleavage sites which include the following sequences: GUA, GUU, and GUC. Once identified, short RNA sequences of between 15 and 20 ribonucleotides conesponding to the region of the target RNA containing the cleavage site can be evaluated for secondary structural features which may render the target inoperable. Suitability of candidate dendritic cell immunoreceptor RNA targets also can be evaluated by testing accessibility to hybridization with complementary oligonucleotides using ribonuclease protection assays. Longer complementary sequences can be used to increase the affinity of the hybridization sequence for the target. The hybridizing and cleavage regions of the ribozyme can be integrally related such that upon hybridizing to the target RNA through the complementary regions, the catalytic region of the ribozyme can cleave the target. Ribozymes can be introduced into cells as part of a DNA construct. Mechanical methods, such as microinjection, liposome-mediated transfection, electroporation, or calcium phosphate precipitation, can be used to introduce a ribozyme-containing DNA construct into cells in which it is desired to decrease dendritic cell immunoreceptor expression. Alternatively, if it is desired that the cells stably retain the DNA construct, the construct can be supplied on a plasmid and maintained as a separate element or integrated into the genome of the cells, as is known in the art. A ribozyme-encoding DNA construct can include transcriptional regulatory elements, such as a promoter element, an enhancer or UAS element, and a transcriptional terminator signal, for controlling transcription of ribozymes in the cells. As taught in Haseloff et al, U.S. Patent 5,641,673, ribozymes can be engineered so that ribozyme expression will occur in response to factors which induce expression of a target gene. Ribozymes also can be engineered to provide an additional level of regulation, so that destruction of mRNA occurs only when both a ribozyme and a target gene are induced in the cells. Differentially Expressed Genes Described herein are methods for the identification of genes whose products interact with human dendritic cell immunoreceptor. Such genes may represent genes which are differentially expressed in disorders including, but not limited to, cancer, asthma, obesity, diabetes, CNS disorders, and cardiovascular disorders. Further, such genes may represent genes which are differentially regulated in response to manipulations relevant to the progression or treatment of such diseases. Additionally, such genes may have a temporally modulated expression, increased or decreased at different stages of tissue or organism development. A differentially expressed gene may also have its expression modulated under control versus experimental conditions. In addition, the human dendritic cell immunoreceptor gene or gene product may itself be tested for differential expression. The degree to which expression differs in a normal versus a diseased state need only be large enough to be visualized via standard characterization techniques such as differential display techniques. Other such standard characterization techniques by which expression differences may be visualized include but are not limited to, quantitative RT (reverse transcriptase), PCR, and Northern analysis. Identification of Differentially Expressed Genes To identify differentially expressed genes total RNA or, preferably, mRNA is isolated from tissues of interest. For example, RNA samples are obtained from tissues of experimental subjects and from conesponding tissues of control subjects. Any RNA isolation technique which does not select against the isolation of mRNA may be utilized for the purification of such RNA samples. See, for example, Ausubel et al, ed.„ CURRENT PROTOCOLS IN MOLECULAR BIOLOGY, John Wiley & Sons, Inc. New York, 1987-1993. Large numbers of tissue samples may readily be processed using techniques well known to those of skill in the art, such as, for example, the single-step RNA isolation process of Chomczynski, U.S. Patent 4,843,155. Transcripts within the collected RNA samples which represent RNA produced by differentially expressed genes are identified by methods well known to those of skill in the art. They include, for example, differential screening (Tedder et al, Proc. Natl. Acad. Sci. U.S.A. 85, 208-12, 1988), subfractive hybridization (Hedrick et al, Nature 308, 149-53; Lee et al, Proc. Natl. Acad. Sci. U.S.A. 88, 2825, 1984), and, preferably, differential display (Liang & Pardee, Science 257, 967-71, 1992; U.S. Patent 5,262,311). The differential expression information may itself suggest relevant methods for the treatment of disorders involving the human dendritic cell immunoreceptor. For example, treatment may include a modulation of expression of the differentially expressed genes and/or the gene encoding the human dendritic cell immunoreceptor. The differential expression information may indicate whether the expression or activity of the differentially expressed gene or gene product or the human dendritic cell immunoreceptor gene or gene product are up-regulated or down-regulated. Screening Methods The invention provides assays for screening test compounds which bind to or modulate the activity of a dendritic cell immunoreceptor polypeptide or a dendritic cell immunoreceptor polynucleotide. A test compound preferably binds to a dendritic cell immunoreceptor polypeptide or polynucleotide. More preferably, a test compound decreases or increases dendritic cell immunoreceptor activity by at least about 10, preferably about 50, more preferably about 75, 90, or 100% relative to the absence of the test compound. Te-yt Compounds Test compounds can be pharmacologic agents already known in the art or can be compounds previously unknown to have any pharmacological activity. The com- pounds can be naturally occurring or designed in the laboratory. They can be isolated from microorganisms, animals, or plants, and can be produced recom- binantly, or synthesized by chemical methods known in the art. If desired, test compounds can be obtained using any of the numerous combinatorial library methods known in the art, including but not limited to, biological libraries, spatially addressable parallel solid phase or solution phase libraries, synthetic library methods requiring deconvolution, the "one-bead one-compound" library method, and synthetic library methods using affinity chromatography selection. The biological library approach is limited to polypeptide libraries, while the other four approaches are applicable to polypeptide, non-peptide oligomer, or small molecule libraries of compounds. See Lam, Anticancer Drug Des. 12, 145, 1997. Methods for the synthesis of molecular libraries are well known in the art (see, for example, DeWitt et al, Proc. Natl. Acad. Sci. U.S.A. 90, 6909, 1993; Erb et al. Proc, Natl. Acad, Sci. U.S.A. 91, 11422, 1994; Zuckermann et al, J Med. Chem. 37, 2678, 1994; Cho et al, Science 261, 1303, 1993; Carell et al, Angew. Chem. Int. Ed. Engl 33, 2059, 1994; Carell et al, Angew. Chem. Inl Ed. Engl, 33, 2061; Gallop et al, J. Med. Chem. 37, 1233, 1994). Libraries of compounds can be presented in solution (see, e.g., Houghten, BioTechniques 13, 412-421, 1992), or on beads (Lam, Nature 354, 82-84, 1991), chips (Fodor, Nature 364, 555-556, 1993), bacteria or spores (Ladner, U.S. Patent 5,223,409), plasmids (Cull et al, Proc. Natl. Acad. Sci. U.S.A. 89, 1865-1869, 1992), or phage (Scott & Smith, Science 249, 386-390, 1990; Devlin, Science 249, 404-406, 1990); Cwirla et al, Proc. Natl. Acad. Sci. 97, 6378-6382, 1990; Felici, J Mol. Biol 222, 301-310, 1991; and Ladner, U.S. Patent 5,223,409). High Throughput Screening Test compounds can be screened for the ability to bind to dendritic cell immunoreceptor polypeptides or polynucleotides or to affect dendritic cell immunoreceptor activity or dendritic cell immunoreceptor gene expression using high throughput screening. Using high throughput screening, many discrete compounds can be tested in parallel so that large numbers of test compounds can be quickly screened. The most widely established techniques utilize 96-well microtiter plates. The wells of the microtiter plates typically require assay volumes that range from 50 to 500 μl. In addition to the plates, many instruments, materials, pipettors, robotics, plate washers, and plate readers are commercially available to fit the 96-well format. Alternatively, "free format assays," or assays that have no physical barrier between samples, can be used. For example, an assay using pigment cells (melanocytes) in a simple homogeneous assay for combinatorial peptide libraries is described by Jayawickreme et al, Proc. Nail. Acad. Sci. U.S.A. 19, 1614-18 (1994). The cells are placed under agarose in petri dishes, then beads that carry combinatorial compounds are placed on the surface of the agarose. The combinatorial compounds are partially released the compounds from the beads. Active compounds can be visualized as dark pigment areas because, as the compounds diffuse locally into the gel matrix, the active compounds cause the cells to change colors. Another example of a free format assay is described by Chelsky, "Strategies for Screening Combinatorial Libraries: Novel and Traditional Approaches," reported at the First Annual Conference of The Society for Biomolecular Screening in Philadelphia, Pa. (Nov. 7-10, 1995). Chelsky placed a simple homogenous receptor assay for carbonic anhydrase inside an agarose gel such that the receptor in the gel would cause a color change throughout the gel. Thereafter, beads carrying combinatorial compounds via a photolinker were placed inside the gel and the compounds were partially released by UN-light. Compounds that inhibited the receptor were observed as local zones of inhibition having less color change. Yet another example is described by Salmon et al, Molecular Diversity 2, 57-63 (1996). In this example, combinatorial libraries were screened for compounds that had cytotoxic effects on cancer cells growing in agar. Another high throughput screening method is described in Beutel et al, U.S. Patent 5,976,813. In this method, test samples are placed in a porous matrix. One or more assay components are then placed within, on top of, or at the bottom of a matrix such as a gel, a plastic sheet, a filter, or other form of easily manipulated solid support. When samples are introduced to the porous matrix they diffuse sufficiently slowly, such that the assays can be performed without the test samples running together. Binding Assays For binding assays, the test compound is preferably a small molecule which binds to and occupies, for example, the ligand binding site of the dendritic cell immunoreceptor polypeptide, such that normal biological activity is prevented. Examples of such small molecules include, but are not limited to, small peptides or peptide-like molecules. In binding assays, either the test compound or the dendritic cell immunoreceptor polypeptide can comprise a detectable label, such as a fluorescent, radioisotopic, chemiluminescent, or enzymatic label, such as horseradish peroxidase, alkaline phosphatase, or luciferase. Detection of a test compound which is bound to the dendritic cell immunoreceptor polypeptide can then be accomplished, for example, by direct counting of radioemmission, by scintillation counting, or by determining conversion of an appropriate substrate to a detectable product. Alternatively, binding of a test compound to a dendritic cell immunoreceptor poly- peptide can be determined without labeling either of the interactants. For example, a microphysiometer can be used to detect binding of a test compound with a dendritic cell immunoreceptor polypeptide. A microphysiometer (e.g., Cytosensor™) is an analytical instrument that measures the rate at which a cell acidifies its environment using a light-addressable potentiometric sensor (LAPS). Changes in this acidifi- cation rate can be used as an indicator of the interaction between a test compound and a dendritic cell immunoreceptor polypeptide (McConnell et al, Science 257, 1906-1912, 1992). Determining the ability of a test compound to bind to a dendritic cell immuno- receptor polypeptide also can be accomplished using a technology such as real-time Bimolecular Interaction Analysis (BIA) (Sjolander & Urbaniczky, Anal Chem. 63, 2338-2345, 1991, and Szabo et al, Curr. Opin. Struct. Biol. 5, 699-705, 1995). BIA is a technology for studying biospecific interactions in real time, without labeling any of the interactants (e.g., BlAcore ). Changes in the optical phenomenon surface plasmon resonance (SPR) can be used as an indication of real-time reactions between biological molecules. In yet another aspect of the invention, a dendritic cell immunoreceptor polypeptide can be used as a "bait protein" in a two-hybrid assay- -or three-hybrid assay (see, e.g., U.S. Patent 5,283,317; Zervos et al, Cell 72, 223-232, 1993; Madura et al, J. Biol Chem. 268, 12046-12054, 1993; Barrel et al, BioTechniques 14, 920-924, 1993; Iwabuchi et al, Oncogene 8, 1693-1696, 1993; and Brent W094/10300), to identify other proteins which bind to or interact with the dendritic cell immunoreceptor polypeptide and modulate its activity. The two-hybrid system is based on the modular nature of most transcription factors, which consist of separable DNA-binding and activation domains. Briefly, the assay utilizes two different DNA constructs. For example, in one construct, polynucleotide encoding a dendritic cell immunoreceptor polypeptide can be fused to a poly- nucleotide encoding the DNA binding domain of a known transcription factor (e.g., GAL-4). In the other construct a DNA sequence that encodes an unidentified protein ("prey" or "sample") can be fused to a polynucleotide that codes for the activation domain of the known transcription factor. If the "bait" and the "prey" proteins are able to interact in vivo to form an protein-dependent complex, the DNA-binding and activation domains of the transcription factor are brought into close proximity. This proximity allows transcription of a reporter gene (e.g., LacZ), which is operably linked to a transcriptional regulatory site responsive to the transcription factor. Expression of the reporter gene can be detected, and cell colonies containing the functional transcription factor can be isolated and used to obtain the DNA sequence encoding the protein which interacts with the dendritic cell immunoreceptor polypeptide. It may be desirable to immobilize either the dendritic cell immunoreceptor polypeptide (or polynucleotide) or the test compound to facilitate separation of bound from unbound forms of one or both of the interactants, as well as to accommodate automation of the assay. Thus, either the dendritic cell immunoreceptor polypeptide (or polynucleotide) or the test compound can be bound to a solid support. Suitable solid supports include, but are not limited to, glass or plastic slides, tissue culture plates, microtiter wells, tubes, silicon chips, or particles such as beads (including, but not limited to, latex, polystyrene, or glass beads). Any method known in the art can be used to attach the receptor polypeptide (or polynucleotide) or test compound to a solid support, including use of covalent and non-covalent linkages, passive absorption, or pairs of binding moieties attached respectively to the polypeptide (or polynucleotide) or test compound and the solid support. Test compounds are preferably bound to the solid support in an array, so that the location of individual test compounds can be tracked. Binding of a test compound to a dendritic cell immunoreceptor polypeptide (or polynucleotide) can be accomplished in any vessel suitable for containing the reactants. Examples of such vessels include microtiter plates, test tubes, and microcentrifuge tubes. In one embodiment, the dendritic cell immunoreceptor polypeptide is a fusion protein comprising a domain that allows the dendritic cell immunoreceptor polypeptide to be bound to a solid support. For example, glutathione-S-transferase fusion proteins can be adsorbed onto glutathione sepharose beads (Sigma Chemical, St. Louis, Mo.) or glutathione derivatized microtiter plates, which are then combined with the test compound or the test compound and the non-adsorbed dendritic cell immunoreceptor polypeptide; the mixture is then incubated under conditions conducive to complex fonnation (e.g., at physiological conditions for salt and pH). Following incubation, the beads or microtiter plate wells are washed to remove any unbound components. Binding of the interactants can be determined either directly or indirectly, as described above. Alternatively, the complexes can be dissociated from the solid support before binding is determined. Other techniques for immobilizing proteins or polynucleotides on a solid support also can be used in the screening assays of the invention. For example, either a dendritic cell immunoreceptor polypeptide (or polynucleotide) or a test compound can be immobilized utilizing conjugation of biotin and streptavidin. Biotinylated dendritic cell immunoreceptor polypeptides (or polynucleotides) or test compounds can be prepared from biotin-NHS(N-hydroxysuccinimide) using techniques well known in the art (e.g., biotinylation kit, Pierce Chemicals, Rockford, 111.) and immobilized in the wells of strep tavidin-coated 96 well plates (Pierce Chemical). Alternatively, antibodies which specifically bind to a dendritic cell immunoreceptor polypeptide, polynucleotide, or a test compound, but which do not interfere with a desired binding site, such as the ligand binding site of the dendritic cell immunoreceptor polypeptide, can be derivatized to the wells of the plate. Unbound target or protein can be trapped in the wells by antibody conjugation. Methods for detecting such complexes, in addition to those described above for the GST-immobilized complexes, include immunodetection of complexes using antibodies which specifically bind to the dendritic cell immunoreceptor polypeptide or test compound, receptor-linked assays which rely on detecting an activity of the dendritic cell immunoreceptor polypeptide, and SDS gel electrophoresis under non- reducing conditions. Screening for test compounds which bind to a dendritic cell immunoreceptor polypeptide or polynucleotide also can be carried out in an intact cell. Any cell which comprises a dendritic cell immunoreceptor polypeptide or polynucleotide can be used in a cell-based assay system. A dendritic cell immunoreceptor polynucleo- tide can be naturally occurring in the cell or can be introduced using techniques such as those described above. Binding of the test compound to a dendritic cell immunoreceptor polypeptide or polynucleotide is determined as described above. Functional Assays Test compounds can be tested for the ability to increase or decrease a biological effect of a human dendritic cell immunoreceptor polypeptide. Such biological effects can be determined using the functional assays described in the specific examples, below. Functional assays can be carried out after contacting either a purified polypeptide, a cell membrane preparation, or an intact cell with a test compound. A test compound which decreases a functional activity of a human dendritic cell immunoreceptor polypeptide by at least about 10, preferably about 50, more preferably about 75, 90, or 100% is identified as a potential agent for decreasing the activity of a human dendritic cell immunoreceptor polypeptide. A test compound which increases a functional activity by at least about 10, preferably about 50, more preferably about 75, 90, or 100% is identified as a potential agent for increasing the activity of a human dendritic cell immunoreceptor polypeptide. Gene Expression In another embodiment, test compounds which increase or decrease dendritic cell immunoreceptor gene expression are identified. A dendritic cell immunoreceptor polynucleotide is contacted with a test compound, and the expression of an RNA or polypeptide product of the dendritic cell immunoreceptor polynucleotide is determined. The level of expression of appropriate mRNA or polypeptide in the presence of the test compound is compared to the level of expression of mRNA or polypeptide in the absence of the test compound. The test compound can then be identified as a modulator of expression based on this comparison. For example, when expression of mRNA or polypeptide is greater in the presence of the test compound than in its absence, the test compound is identified as a stimulator or enhancer of the mRNA or polypeptide expression. Alternatively, when expression of the mRNA or polypeptide is less in the presence of the test compound than in its absence, the test compound is identified as an inhibitor of the mRNA or polypeptide expression. The level of dendritic cell immunoreceptor mRNA or polypeptide expression in the cells can be determined by methods well known in the art for detecting mRNA or polypeptide. Either qualitative or quantitative methods can be used. The presence of polypeptide products of a dendritic cell immunoreceptor polynucleotide can be determined, for example, using a variety of techniques known in the art, including immunochemical methods such as radioimmunoassay, Western blotting, and imrnunohistochemistry. Alternatively, polypeptide synthesis can be determined in vivo, in a cell culture, or in an in vitro translation system by detecting incorporation of labeled amino acids into a dendritic cell immunoreceptor polypeptide. Such screening can be carried out either in a cell-free assay system or in an intact cell. Any cell which expresses a dendritic cell immunoreceptor polynucleotide can be used in a cell-based assay system. The dendritic cell immunoreceptor polynucleotide can be naturally occuning in the cell or can be introduced using techniques such as those described above. Either a primary culture or an established cell line, such as CHO or human embryonic kidney 293 cells, can be used. Pharmaceutical Compositions The invention also provides pharmaceutical compositions which can be administered to a patient to achieve a therapeutic effect. Pharmaceutical compositions of the invention can comprise, for example, a dendritic cell immunoreceptor polypeptide, dendritic cell immunoreceptor polynucleotide, ribozymes or antisense oligonucleotides, antibodies which specifically bind to a dendritic cell immunoreceptor poly- peptide, or mimetics, agonists, antagonists, or inhibitors of a dendritic cell immunoreceptor polypeptide activity. The compositions can be administered alone or in combination with at least one other agent, such as stabilizing compound, which can be administered in any sterile, biocompatible pharmaceutical carrier, including, but not limited to, saline, buffered saline, dextrose, and water. The compositions can be administered to a patient alone, or in combination with other agents, drugs or hormones. In addition to the active ingredients, these pharmaceutical compositions can contain suitable pharmaceutically-acceptable carriers comprising excipients and auxiliaries which facilitate processing of the active compounds into preparations which can be used pharmaceutically. Pharmaceutical compositions of the invention can be administered by any number of routes including, but not limited to, oral, intravenous, intramuscular, intra-arterial, intramedullary, intrathecal, intraventricular, transdermal, subcutaneous, intraperitoneal, intranasal, parenteral, topical, sublingual, or rectal means. Pharmaceutical compositions for oral administration can be formulated using pharmaceutically acceptable carriers well known in the art in dosages suitable for oral administration. Such caniers enable the pharmaceutical compositions to be formulated as tablets, pills, dragees, capsules, liquids, gels, syrups, slurries, suspensions, and the like, for ingestion by the patient. Pharmaceutical preparations for oral use can be obtained through combination of active compounds with solid excipient, optionally grinding a resulting mixture, and processing the mixture of granules, after adding suitable auxiliaries, if desired, to obtain tablets or dragee cores. Suitable excipients are carbohydrate or protein fillers, such as sugars, including lactose, sucrose, mannitol, or sorbitol; starch from corn, wheat, rice, potato, or other plants; cellulose, such as methyl cellulose, hydroxypropylmethyl-cellulose, or sodium carboxymethylcellulose; gums including arabic and tragacanth; and proteins such as gelatin and collagen. If desired, disintegrating or solubilizing agents can be added, such as the cross-linked polyvinyl pyrrolidone, agar, alginic acid, or a salt thereof, such as sodium alginate. Dragee cores can be used in conjunction with suitable coatings, such as concentrated sugar solutions, which also can contain gum arabic, talc, polyvinylpyrrolidone, carbopol gel, polyethylene glycol, and/or titanium dioxide, lacquer solutions, and suitable organic solvents or solvent mixtures. Dyestuffs or pigments can be added to the tablets or dragee coatings for product identification or to characterize the quantity of active compound, i.e., dosage. Pharmaceutical preparations which can be used orally include push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a coating, such as glycerol or sorbitol. Push-fit capsules can contain active ingredients mixed with a filler or binders, such as lactose or starches, lubricants, such as talc or magnesium stearate, and, optionally, stabilizers. In soft capsules, the active compounds can be dissolved or suspended in suitable liquids, such as fatty oils, liquid, or liquid polyethylene glycol with or without stabilizers. Pharmaceutical formulations suitable for parenteral administration can be formulated in aqueous solutions, preferably in physiologically compatible buffers such as Hanks' solution, Ringer's solution, or physiologically buffered saline. Aqueous injection suspensions can contain substances which increase the viscosity of the suspension, such as sodium carboxymethyl cellulose, sorbitol, or dextran. Additionally, suspensions of the active compounds can be prepared as appropriate oily injection suspensions. Suitable lipophilic solvents or vehicles include fatty oils such as sesame oil, or synthetic fatty acid esters, such as ethyl oleate or triglycerides, or liposomes. Non-lipid polycationic amino polymers also can be used for delivery. Optionally, the suspension also can contain suitable stabilizers or agents which increase the solubility of the compounds to allow for the preparation of highly concentrated solutions. For topical or nasal administration, penetrants appropriate to the particular barrier to be permeated are used in the formulation. Such penetrants are generally known in the art. The pharmaceutical compositions of the present invention can be manufactured in a manner that is known in the art, e.g., by means of conventional mixing, dissolving, granulating, dragee-making, levigating, emulsifying, encapsulating, entrapping, or lyophilizing processes. The pharmaceutical composition can be provided as a salt and can be formed with many acids, including but not limited to, hydrochloric, sulfuric, acetic, lactic, tartaric, malic, succinic, etc. Salts tend to be more soluble in aqueous or other protonic solvents than are the conesponding free base forms. In other cases, the prefened preparation can be a lyophilized powder which can contain any or all of the following: 1-50 mM histidine, 0.1%-2% sucrose, and 2-7% mannitol, at a pH range of 4.5 to 5.5, that is combined with buffer prior to use. Further details on techniques for formulation and administration can be found in the latest edition of REMINGTON'S PHARMACEUTICAL SCIENCES (Maack Publishing Co., Easton, Pa.). After pharmaceutical compositions have been prepared, they can be placed in an appropriate container and labeled for treatment of an indicated condition. Such labeling would include amount, frequency, and method of administration. Therapeutic Indications and Methods Human dendritic cell immunoreceptor can be regulated to treat cancer, asthma, obesity, diabetes, CNS disorders, and cardiovascular disorders. Cancer is a disease fundamentally caused by oncogenic cellular transformation. There are several hallmarks of transformed cells that distinguish them from their normal counterparts and underlie the pathophysiology of cancer. These include uncontrolled cellular proliferation, unresponsiveness to normal death-inducing signals (immortalization), increased cellular motility and invasiveness, increased ability to recruit blood supply through induction of new blood vessel formation (angiogenesis), genetic instability, and dysregulated gene expression. Various combinations of these abenant physiologies, along with the acquisition of drug- resistance frequently lead to an intractable disease state in which organ failure and patient death ultimately ensue. Most standard cancer therapies target cellular proliferation and rely on the differential proliferative capacities between transformed and normal cells for their efficacy. This approach is hindered by the facts that several important normal cell types are also highly proliferative and that cancer cells frequently become resistant to these agents. Thus, the therapeutic indices for traditional anti-cancer therapies rarely exceed 2.0. The advent of genomics-driven molecular target identification has opened up the possibility of identifying new cancer-specific targets for therapeutic intervention that will provide safer, more effective treatments for cancer patients. Thus, newly discovered tumor-associated genes and their products.can be tested for their role(s) in disease and used as tools to discover and develop innovative therapies. Genes playing important roles in any of the physiological processes outlined above can be characterized as cancer targets. Genes or gene fragments identified through genomics can readily be expressed in one or more heterologous expression systems to produce functional recombinant proteins. These proteins are characterized in vitro for their biochemical properties and then used as tools in high-throughput molecular screening programs to identify chemical modulators of their biochemical activities. Agonists and/or antagonists of target protein activity can be identified in this manner and subsequently tested in cellular and in vivo disease models for anti-cancer activity. Optimization of lead compounds with iterative testing in biological models and detailed pharmacokinetic and toxicological analyses form the basis for drug development and subsequent testing in humans. Allergy, anaphylaxis, asthma and inflammation. Allergy is a complex process in which environmental antigens induce clinically adverse reactions. The inducing antigens, called allergens, typically elicit a specific IgE response and, although in most cases the allergens themselves have little or no intrinsic toxicity, they induce pathology when the IgE response in turn elicits an IgE-dependent or T cell-dependent hypersensitivity reaction. Hypersensitivity reactions can be local or systemic and typically occur within minutes of allergen exposure in individuals who have previously been sensitized to an allergen. The hypersensitivity reaction of allergy develops when the allergen is recognized by IgE antibodies bound to specific receptors on the surface of effector cells, such as mast cells, basophils, or eosinophils, which causes the activation of the effector cells and the release of mediators that produce the acute signs and symptoms of the reactions. Allergic diseases include asthma, allergic rhinitis (hay fever), atopic dermatitis, and anaphylaxis. Asthma is though to arise as a result of interactions, between multiple genetic and environmental factors and is characterized by three major features: 1) intermittent and reversible airway obstruction caused by bronchoconstriction, increased mucus production, and thickening of the walls of the airways that leads to a narrowing of the airways, 2) airway hypenesponsiveness caused by a decreased control of airway caliber, and 3) airway inflammation. Certain cells are critical to the inflammatory reaction of asthma and they include T cells and antigen presenting cells, B cells that produce IgE, and mast cells, basophils, eosinophils, and other cells that bind IgE. These effector cells accumulate at the site of allergic reaction in the airways and release toxic products that contribute to the acute pathology and eventually to the tissue destruction related to the disorder. Other resident cells, such as smooth muscle cells, lung epithelial cells, mucus-producing cells, and nerve cells may also be abnormal in individuals with asthma and may contribute to the pathology. While the airway obstruction of asthma, presenting clinically as an intermittent wheeze and shortness of breath, is generally the most pressing symptom of the disease requiring immediate treatment, the inflammation and tissue destruction associated with the disease can lead to irreversible changes that eventually make asthma a chronic disabling disorder requiring long-term management. Despite recent important advances in our understanding of the pathophysiology of asthma, the disease appears to be increasing in prevalence and severity (Gergen and Weiss, Am. Rev. Respir. Dis. 146, 823-24, 1992). It is estimated that 30-40% of the population suffer with atopic allergy, and 15% of children and 5% of adults in the population suffer from asthma (Gergen and Weiss, 1992). Thus, an enormous burden is placed on our health care resources. However, both diagnosis and treatment of asthma are difficult. The severity of lung tissue inflammation is not easy to measure and the symptoms of the disease are often indistinguishable from those of respiratory infections, chronic respiratory inflammatory disorders, allergic rhinitis, or other respiratory disorders. Often, the inciting allergen cannot be determined, making removal of the causative environmental agent difficult. Current pharmacological treatments suffer their own set of disadvantages. Commonly used therapeutic agents, such as beta agonists, can act as symptom relievers to.transiently improve pulmonary function, but do not affect the underlying inflammation. Agents that can reduce the underlying inflammation, such as anti-inflammatory steroids, can have major drawbacks that range from immunosuppression to bone loss (Goodman and Gilman's THE PHARMACOLOGIC BASIS OF THERAPEUTICS, Seventh Edition, MacMillan Publishing Company, NY, USA, 1985). In addition, many of the present therapies, such as inhaled corticosteroids, are short-lasting, inconvenient to use, and must be used often on a regular basis, in some cases for life, making failure of patients to comply with the treatment a major problem and thereby reducing their effectiveness as a treatment. Because of the problems associated with conventional therapies, alternative treatment strategies have been evaluated. Glycophorin A (Chu and Sharom, Cell. Immunol. 145, 223-39, 1992), cyclosporin (Alexander et al, Lancet 339, 324-28, 1992), and a nonapeptide fragment of IL-2 (Zav'yalov et al, Immunol. Lett. 31, 285-88, 1992) all inhibit interleukin-2 dependent T lymphocyte proliferation; however, they are known to have many other effects. For example, cyclosporin is used as a immuno- suppressant after organ transplantation. While these agents may represent alterna- tives to steroids in the treatment of asthmatics, they inhibit interleukin-2 dependent T lymphocyte proliferation and potentially critical immune functions associated with homeostasis. Other treatments that block the release or activity of mediators of bronchochonstriction, such as cromones or anti-leukotrienes, have recently been introduced for the treatment of mild asthma, but they are expensive and not effective in all patients and it is unclear whether they have any effect on the chronic changes associated with asthmatic inflammation. What is needed in the art is the identification of a treatment that can act in pathways critical to the development of asthma_that both blocks the episodic attacks of the disorder and preferentially dampens the hyperactive allergic immune response without immunocompromising the patient. Diabetes mellitus. Diabetes mellitus is a common metabolic disorder characterized by an abnormal elevation in blood glucose, alterations in lipids and abnormalities (complications) in the cardiovascular system, eye, kidney and nervous system. Diabetes is divided into two separate diseases: type 1 diabetes (juvenile onset), which results from a loss of cells which make and secrete insulin, and type 2 diabetes (adult onset), which is caused by a defect in insulin secretion and a defect in insulin action. Type 1 diabetes is initiated by an autoimmune reaction that attacks the insulin secreting cells (beta cells) in the pancreatic islets. Agents that prevent this reaction from occurring or that stop the reaction before destruction of the beta cells has been accomplished are potential therapies for this disease. Other agents that induce beta cell proliferation and regeneration also are potential therapies. Type II diabetes is the most common of the two diabetic conditions (6% of the population). The defect in insulin secretion is an important cause of the diabetic condition and results from an inability of the beta cell to properly detect and respond to rises in blood glucose levels with insulin release. Therapies that increase the response by the beta cell to glucose would offer an important new treatment for this disease. The defect in insulin action in Type II diabetic subjects is another target for therapeutic intervention. Agents that increase the activity of the insulin receptor in muscle, liver, and fat will cause a decrease in blood glucose and a normalization of plasma lipids. The receptor activity can be increased by agents that directly stimulate the receptor or that increase the intracellular signals from the receptor. Other therapies can directly activate the cellular end process, i.e. glucose transport or various enzyme systems, to generate an insulin-like effect and therefore a produce beneficial outcome. Because overweight subjects have a greater susceptibility to Type II diabetes, any agent that reduces body weight is a possible therapy. Both Type I and Type diabetes can be treated with agents that mimic insulin action or that treat diabetic complications by reducing blood glucose levels. Likewise, agents that reduces new blood vessel growth can be used to treat the eye complications that develop in both diseases. CNS disorders which may be treated include brain injuries, cerebrovascular diseases and their consequences, Parkinson's disease, corticobasal degeneration, motor neuron disease, dementia, including ALS, multiple sclerosis, traumatic brain injury, stroke, post-stroke, post-traumatic brain injury, and small-vessel cerebrovascular disease. Dementias, such as Alzheimer's disease, vascular dementia, dementia with Lewy bodies, frontotemporal dementia and Parkinsonism linked to chromosome 17, frontotemporal dementias, including Pick's disease, progressive nuclear palsy, corticobasal degeneration, Huntington's disease, thalamic degeneration, Creutzfeld- Jakob dementia, HIV dementia, schizophrenia with dementia, and Korsakoff s psychosis also can be treated. Similarly, it may be possible to treat cognitive-related disorders, such as mild cognitive impairment, age-associated memory impairment, age-related cognitive decline, vascular cognitive impairment, attention deficit disorders, attention deficit hyperactivity disorders, and memory disturbances in children with learning disabilities, by regulating the activity of human dendritic cell immunoreceptor. Chronic obstructive pulmonary (or airways) disease (COPD) is a condition defined physiologically as airflow obstruction that generally results from a mixture of emphysema and peripheral airway obstruction due to chronic bronchitis (Senior & Shapiro, Pulmonary Diseases and Disorders, 3d ed., New York, McGraw-Hill, 1998, pp. 659-681, 1998; Barnes, Chest 117, 10S-14S, 2000). Emphysema is characterized by destruction of alveolar walls leading to abnormal enlargement of the air spaces of the lung. Chronic bronchitis is defined clinically as the presence of chronic productive cough for three months in each of two successive years. In COPD, airflow obstruction is usually progressive and is only partially reversible. By far the most important risk factor for development of COPD is cigarette smoking, although the disease does occur in non-smokers. Chronic inflammation of the airways is a key pathological feature of COPD (Senior & Shapiro, 1998). The inflammatory cell population comprises increased numbers of macrophages, neutrophils, and CD 8 lymphocytes. Inhaled irritants, such as cigarette smoke, activate macrophages which are resident in the respiratory tract, as well as epithelial cells leading to release of chemokines (e.g., interleukin-8) and other chemotactic factors. These chemotactic factors act to increase the neutrophil/- monocyte trafficking from the blood into the lung tissue and airways. Neutrophils and monocytes recruited into the airways can release a variety of potentially damaging mediators such as proteolytic enzymes and reactive oxygen species. Matrix degradation and emphysema, along with airway wall thickening, surfactant dysfunction, and mucus hypersecretion, all are potential sequelae of this inflammatory response that lead to impaired airflow and gas exchange. Obesity and overweight are defined as an excess of body fat relative to lean body mass. An increase in caloric intake or a decrease in energy expenditure or both can bring about this imbalance leading to surplus energy being stored as fat. Obesity is associated with important medical morbidities and an increase in mortality. The causes of obesity are poorly understood and may be due to genetic factors, environmental factors or a combination of the two to cause a positive energy balance. In contrast, anorexia and cachexia are characterized by an imbalance in energy intake versus energy expenditure leading to a negative energy balance and weight loss. Agents that either increase energy expenditure and/or decrease energy intake, absorption or storage would be useful for treating obesity, overweight, and associated comorbidities. Agents that either increase energy intake and/or decrease energy expenditure or increase the amount of lean tissue would be useful for treating cachexia, anorexia and wasting disorders. This gene, translated proteins and agents which modulate this gene or portions of the gene or its products are useful for treating obesity, overweight, anorexia, cachexia, wasting disorders, appetite suppression, appetite enhancement, increases or decreases in satiety, modulation of body weight, and/or other eating disorders such as bulimia. Also this gene, translated proteins and agents which modulate this gene or portions of the gene or its products are useful for treating obesity/overweight-associated comorbidities including hypertension, type 2 diabetes, coronary artery disease, hyperlipidemia, stroke, gallbladder disease, gout, osteoarthritis, sleep apnea and respiratory problems, some types of cancer including endometrial, breast, prostate, and colon cancer, thrombolic disease, polycystic ovarian syndrome, reduced fertility, complications of pregnancy, menstrual irregularities, hirsutism, stress incontinence, and depression. This invention further pertains to the use of novel agents identified by the screening assays described above. Accordingly, it is within the scope of this invention to use a test compound identified as described herein in an appropriate animal model. For example, an agent identified as described herein (e.g., a modulating agent, an antisense nucleic acid molecule, a specific antibody, ribozyme, or a dendritic cell immunoreceptor polypeptide binding molecule) can be used in an animal model to determine the efficacy, toxicity, or side effects of treatment with such an agent. Alternatively, an agent identified as described herein can be used in an animal model to determine the mechanism of action of such an agent. Furthermore, this invention pertains to uses of novel agents identified by the above-described screening assays for treatments as described herein. Cardiovascular diseases include the following disorders of the heart and the vascular system: congestive heart failure, myocardial infarction, ischemic diseases of the heart, all kinds of atrial and ventricular anhythmias, hypertensive vascular diseases, and peripheral vascular diseases. Heart failure is defined as a pathophysiologic state in which an abnormality of cardiac function is responsible for the failure of the heart to pump blood at a rate commensurate with the requirement of the metabolizing tissue. It includes all forms of pumping failure, such as high-output and low-output, acute and chronic, right- sided or left-sided, systolic or diastolic, independent of the underlying cause. Myocardial infarction (MI) is generally caused by an abrupt decrease in coronary blood flow that follows a thrombotic occlusion of a coronary artery previously narrowed by arteriosclerosis. MI prophylaxis (primary and secondary prevention) is included, as well as the acute treatment of MI and the prevention of complications. Ischemic diseases are conditions in which the coronary flow is restricted resulting in a perfusion which is inadequate to meet the myocardial requirement for oxygen. This group of diseases includes stable angina, unstable angina, and asymptomatic ischemia. Arrhythmias include all forms of atrial and ventricular tachyarrhythmias (atrial tachycardia, atrial flutter, atrial fibrillation, atrio-ventricular reentrant tachycardia, preexcitation syndrome, ventricular tachycardia, ventricular flutter, and ventricular fibrillation), as well as bradycardic forms of anhythmias. Hypertensive vascular diseases include primary as well as all kinds of secondary arterial hypertension (renal, endocrine, neurogenic, others). The disclosed gene and its product may be used as drug targets for the treatment of hypertension as well as for the prevention of all complications. Peripheral vascular diseases are defined as vascular diseases in which arterial and/or venous flow is reduced resulting in an imbalance between blood supply and tissue oxygen demand. It includes chronic peripheral arterial occlusive disease (PAOD), acute arterial thrombosis and embolism, inflammatory vascular disorders, Raynaud's phenomenon, and venous disorders. A reagent which affects dendritic cell immunoreceptor activity can be administered to a human cell, either in vitro or in vivo, to reduce dendritic cell immunoreceptor activity. The reagent preferably binds to an expression product of a human dendritic cell immunoreceptor gene. If the expression product is a protein, the reagent is preferably an antibody. For treatment of human cells ex vivo, an antibody can be added to a preparation of stem cells which have been removed from the body. The cells can then be replaced in the same or another human body, with or without clonal propagation, as is known in the art. In one embodiment, the reagent is delivered using a liposome. Preferably, the liposome is stable in the animal into which it has been administered for at least about 30 minutes, more preferably for at least about 1 hour, and even more preferably for at least about 24 hours. A liposome comprises a. lipid composition that is capable of targeting a reagent, particularly a polynucleotide, to a particular site in an animal, such as a human. Preferably, the lipid composition of the liposome is capable of targeting to a specific organ of an animal, such as the lung, liver, spleen, heart brain, lymph nodes, and skin. A liposome useful in the present invention comprises a lipid composition that is capable of fusing with the plasma membrane of the targeted cell to deliver its contents to the cell. Preferably, the transfection efficiency of a liposome is about 0.5 μg of DNA per 16 nmole of liposome delivered to about 10 6 cells, more preferably about 1.0 μg of DNA per 16 nmole of liposome delivered to about 10 6 cells, and even more preferably about 2.0 μg of DNA per 16 nmol of liposome delivered to about 10 6 cells. Preferably, a liposome is between about 100 and 500 nm, more preferably between about 150 and 450 nm, and even more preferably between about 200 and 400 nm in diameter. Suitable liposomes for use in the present invention include those liposomes standardly used in, for example, gene delivery methods known to those of skill in the art. More preferred liposomes include liposomes having a polycationic lipid composition and/or liposomes having a cholesterol backbone conjugated to polyethylene glycol. Optionally, a liposome comprises a compound capable of targeting the liposome to a particular cell type, such as a cell-specific ligand exposed on the outer surface of the liposome. Complexing a liposome with a reagent such as an antisense oligonucleotide or ribozyme can be achieved using methods which are standard in the art (see, for example, U.S. Patent 5,705,151). Preferably, from about 0.1 μg to about 10 μg of polynucleotide is combined with about 8 nmol of liposomes, more preferably from about 0.5 μg to about 5 μg of polynucleotides are combined with about 8 nmol liposomes, and even more preferably about 1.0 μg of polynucleotides is combined with about 8 nmol liposomes. In another embodiment, antibodies can be delivered to specific tissues in vivo using receptor-mediated targeted delivery. Receptor-mediated DNA delivery techniques are taught in, for example, Findeis et al. Trends in Biotechnol. 11, 202-05 (1993); Chiou et al, GENE THERAPEUTICS: METHODS AND APPLICATIONS OF DIRECT GENE TRANSFER (LA. Wolff, ed.) (1994); Wu & Wu, J. Biol. Chem. 263, 621-24 (1988); Wu et al, J. Biol. Chem. 269, 542-46 (1994); Zenke et al, Proc. Natl. Acad. Sci. U.S.A. 87, 3655-59 (1990); Wu et al, J. Biol. Chem. 266, 338-42 (1991). Determination of a Therapeutically Effective Dose The determination of a therapeutically effective dose is well within the capability of those skilled in the art. A therapeutically effective dose refers to that amount of active ingredient which increases or decreases dendritic cell immunoreceptor activity relative to the dendritic cell immunoreceptor activity which occurs in the absence of the therapeutically effective dose. For any compound, the therapeutically effective dose can be estimated initially either in cell culture assays or in animal models, usually mice, rabbits, dogs, or pigs. The animal model also can be used to determine the appropriate concentration range and route of administration. Such information can then be used to determine useful doses and routes for administration in humans. Therapeutic efficacy and toxicity, e.g., ED 50 (the dose therapeutically effective in 50%) of the population) and LD 5 o (the dose lethal to 50% of the population), can be determined by standard pharmaceutical procedures in cell cultures or experimental animals. The dose ratio of toxic to therapeutic effects is the therapeutic index, and it can be expressed as the ratio, LD 5 0/ED 50 . Pharmaceutical compositions which exhibit large therapeutic indices are preferred. The data obtained from cell culture assays and animal studies is used in formulating a range of dosage for human use. The dosage, contained in such compositions is preferably within a range of circulating concentrations that include the ED 50 with little or no toxicity. The dosage varies within this range depending upon the dosage form employed, sensitivity of the patient, and the route of administration. The exact dosage will be determined by the practitioner, in light of factors related to the subject that requires treatment. Dosage and administration are adjusted to provide sufficient levels of the active ingredient or to maintain the desired effect. Factors which can be taken into account include the severity of the disease state, general health of the subject, age, weight, and gender of the subject, diet, time and frequency of administration, drug combination(s), reaction sensitivities, and tolerance/response to therapy. Long-acting pharmaceutical compositions can be administered every 3 to 4 days, every week, or once every two weeks depending on the half-life and clearance rate of the particular formulation. Normal dosage amounts can vary from 0.1 to 100,000 micro grams, up to a total dose of about 1 g, depending upon the route of administration. Guidance as to particular dosages and methods of delivery is provided in the literature and generally available to practitioners in the art. Those skilled in the art will employ different formulations for nucleotides than for proteins or their inhibitors. Similarly, delivery of polynucleotides or polypeptides will be specific to particular cells, conditions, locations, etc. If the reagent is a single-chain antibody, polynucleotides encoding the antibody can be constructed and introduced into a cell either ex vivo or in vivo using well- established techniques including, but not limited to, transferrin-polycation-mediated DNA transfer, transfection with naked or encapsulated nucleic acids, liposome- mediated cellular fusion, intracellular transportation of DNA-coated latex beads, protoplast fusion, viral infection, electroporation, "gene gun," and DEAE- or calcium phosphate-mediated transfection. Effective in vivo dosages of an antibody are in the range of about 5 μg to about 50 μg/kg, about 50 μg to about 5 mg/kg, about 100 μg to about 500 μg kg of patient body weight, and about 200 to about 250 μg/kg of patient body weight. For administration of polynucleotides encoding single-chain antibodies, effective in vivo dosages are in the range of about 100 ng to about 200 ng, 500 ng to about 50 mg, about 1 μg to about 2 mg, about 5 μg to about 500 μg, and about 20 μg to about 100 μg of DNA. If the expression product is mRNA, the reagent is preferably an antisense oligonucleotide or a ribozyme. Polynucleotides which express antisense oligonucleotides or ribozymes can be introduced into cells by a variety of methods, as described above. Preferably, a reagent reduces expression of a dendritic cell immunoreceptor gene or the activity of a dendritic cell immunoreceptor polypeptide by at least about 10, preferably about 50, more preferably about 75, 90, or 100%> relative to the absence of the reagent. The effectiveness of the mechanism chosen to decrease the level of expression of a dendritic cell immunoreceptor gene or the activity of a dendritic cell immunoreceptor polypeptide can be assessed using methods well known in the art, such as hybridization of nucleotide probes to dendritic cell immunoreceptor-specific mRNA, quantitative RT-PCR, immunologic detection of a dendritic cell immunoreceptor polypeptide, or measurement of dendritic cell immunoreceptor activity. In any of the embodiments described above, any of the pharmaceutical compositions of the invention can be administered in combination with other appropriate therapeutic agents. Selection of the appropriate agents for use in combination therapy can be made by one of ordinary skill in the art, according to conventional pharmaceutical principles. The combination of therapeutic agents can act synergistically to effect the treatment or prevention of the various disorders described above. Using this approach, one may be able to achieve therapeutic efficacy with lower dosages of each agent, thus reducing the potential for adverse side effects. Any of the therapeutic methods described above can be applied to any subject in need of such therapy, including, for example, mammals such as dogs, cats, cows, horses, rabbits, monkeys, and most preferably, humans. Diagnostic Methods Human dendritic cell immunoreceptor also can be used in diagnostic assays for detecting diseases and abnormalities or susceptibility to diseases and abnormalities related to the presence of mutations in the nucleic acid sequences which encode the receptor. For example, differences can be determined between the cDNA or genomic sequence encoding dendritic cell immunoreceptor in individuals afflicted with a disease and in normal individuals. If a mutation is observed in some or all of the afflicted individuals but not in normal individuals, then the mutation is likely to be the causative agent of the disease. Sequence differences between a reference gene and a gene having mutations can be revealed by the direct DNA sequencing method. In addition, cloned DNA segments can be employed as probes to detect specific DNA segments. The sensitivity of this method is greatly enhanced when combined with PCR. For example, a sequencing primer can be used with a double-stranded PCR product or a single-stranded template molecule generated by a modified PCR. The sequence determination is performed by conventional procedures using radiolabeled nucleotides or by automatic sequencing procedures using fluorescent tags. Genetic testing based on DNA sequence differences can be carried out 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, for example, by high resolution gel electrophoresis. DNA fragments of different sequences can 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 can also be revealed by nuclease protection assays, such as RNase and S 1 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 can be performed by methods such as hybridization, RNase protection, chemical cleavage, direct DNA sequencing or the use of restriction receptors and Southern blotting of genomic DNA. In addition to direct methods such as gel-electrophoresis and DNA sequencing, mutations can also be detected by in situ analysis. Altered levels of a dendritic cell immunoreceptor also can be detected in various tissues. Assays used to detect levels of the receptor polypeptides in a body sample, such as blood or a tissue biopsy, derived from a host are well known to those of skill in the art and include radioimmunoassays, competitive binding assays, Western blot analysis, and ELISA assays. All patents and patent applications cited in this disclosure are expressly incorporated herein by reference. The above disclosure generally describes the present invention. A more complete understanding can be obtained- by reference to the following specific examples which are provided for purposes of illustration only and are not intended to limit the scope of the invention. EXAMPLE 1 Detection of dendritic cell immunoreceptor polypeptide The polynucleotide of SEQ ID NO: 1 is inserted into the expression vector pCEV4 and the expression vector pCEV4-dendritic cell immunoreceptor polypeptide obtained is transfected into human embryonic kidney 293 cells. From these cells extracts are obtained and centrifuged at 1000 rpm for 5 minutes at 4°C. The supernatant is centrifuged at 30,000 x g for 20 minutes at 4°C. The pellet is suspended in binding buffer containing 50 mM Tris HC1, 5 mM MgSO 4 , 1 mM EDTA, 100 mM NaCl, pH 7.5, supplemented with 0.1 % BSA, 2 μg/ml aprotinin, 0.5 mg/ml leupeptin, and 10 μg/ml phosphoramidon, Optimal membrane suspension dilutions, defined as the protein concentration required to bind less than 10%> of the added radioligand, are added to 96-well polypropylene microtiter plates containing 125 I-labeled ligand or test compound, non-labeled peptides, and binding buffer to a final volume of 250 μL In equilibrium saturation binding assays, membrane preparations are incubated in the presence of increasing concentrations (0.1 nM to 4 nM) of 125 I-labeled ligand or test compound (specific activity 2200 Ci/mmol). The binding affinities of different test compounds are determined in equilibrium competition binding assays, using 0.1 nM 125 I-peptide in the presence of twelve different concentrations of each test compound. Binding reaction mixtures are incubated for one hour at 30 °C. The reaction is stopped by filtration through GF/B filters treated with 0.5% polyethyleneimine, using a cell harvester. Radioactivity is measured by scintillation counting, and data are analyzed by a computerized non-linear regression program. Non-specific binding is defined as the amount of radioactivity remaining after incubation of membrane protein in the presence of 100 nM of unlabeled peptide. Protein concentration is measured by the Bradford method using Bio-Rad Reagent, with bovine serum albumin as a standard. It is shown that the polypeptide of SEQ ID NO: 2 has a dendritic cell immunoreceptor polypeptide activity. EXAMPLE 2 Expression of recombinant human dendritic cell immunoreceptor The Pichia pastoris expression vector pPICZB (Invitrogen, San Diego, CA) is used to produce large quantities of recombinant human dendritic cell immunoreceptor polypeptides in yeast. The dendritic cell immunoreceptor-encoding DNA sequence is derived from SEQ ID NOS: 2 and 15. Before insertion into vector pPICZB, the DNA sequence is modified by well known methods in such a way that it contains at its 5'- end an initiation codon and at its 3 '-end an enterokinase cleavage site, a His6 reporter tag and a termination codon. Moreover, at both termini recognition sequences for restriction endonucleases are added and after digestion of the multiple cloning site of pPICZ B with the corresponding restriction receptors the modified DNA sequence is ligated into pPICZB. This expression vector is designed for inducible expression in Pichia pastoris, driven by a yeast promoter. The resulting pPICZ/md-His6 vector is used to transform the yeast. The yeast is cultivated under usual conditions in 5 liter shake flasks and the recombinantly produced protein isolated from the culture by affinity chromatography (Ni-NTA-Resin) in the presence of 8 M urea. The bound polypeptide is eluted with buffer, pH 3.5, and neutralized. Separation of the polypeptide from the His6 reporter tag is accomplished by site-specific proteolysis using enterokinase (Invitrogen, San Diego, CA) according to manufacturer's instructions. Purified human dendritic cell immunoreceptor polypeptide is obtained. EXAMPLE 3 Identification of test compounds that bind to dendritic cell immunoreceptor polypeptides Purified dendritic cell immunoreceptor polypeptides comprising a glutathione-S- transferase protein and absorbed onto glutathione-derivatized wells of 96-well microtiter plates are contacted with test compounds from a small molecule library at pH 7.0 in a physiological buffer solution. Human dendritic cell immunoreceptor polypeptides comprise the amino acid sequence shown in SEQ ID NOS: 2 and 15. The test compounds comprise a fluorescent tag. The samples are incubated for 5 minutes to one hour. Control samples are incubated in the absence of a test compound. The buffer solution containing the test compounds is washed from the wells. Binding of a test compound to a dendritic cell immunoreceptor polypeptide is detected by fluorescence measurements of the contents of the wells. A test compound which increases the fluorescence in a well by at least 15% relative to fluorescence of a well in which a test compound is not incubated is identified as a compound which binds to a dendritic cell immunoreceptor polypeptide. EXAMPLE 4 Identification of a test compound which decreases dendritic cell immunoreceptor gene expression A test compound is administered to a culture of human cells transfected with a dendritic cell immunoreceptor expression construct and incubated at 37°C for 10 to 45 minutes. A culture of the same type of cells which have not been transfected is incubated for the same time without the test compound to provide a negative control. RNA is isolated from the two cultures as described in Chirgwin et al, Biochem. 18, 5294-99, 1979). Northern blots are prepared using 20 to 30 μg total RNA and hybridized with a 32 P-labeled dendritic cell immunoreceptor-specific probe at 65°C in Express-hyb (CLONTECH). The probe comprises at least 11 contiguous nucleotides selected from the complement of SEQ ID NOS: 1 and 14. A test compound which decreases the dendritic cell immunoreceptor-specific signal relative to the signal obtained in the absence of the test compound is identified as an inhibitor of dendritic cell immunoreceptor gene expression. EXAMPLE 5 Identifying ligands of human dendritic cell immunoreceptor Expression Cloning. Different cell lines can be examined for their capacity to bind soluble forms of human dendritic cell immunoreceptor. A cell line that shows no significant binding is transfected with a cDNA library prepared from a cell line which shows significant binding. Transfectants that bind soluble human dendritic cell immunoreceptor are isolated by FACS or panning. This procedure is repeated to identify the cDNA that encode relevant ligands of human dendritic cell immuno- receptor. Use of Random Peptide Display Library. Mammalian cells transfected with human dendritic cell immunoreceptor cDNA are used to identify peptides that bind to human dendritic cell immunoreceptor. Specifically, E. coli expressing a random peptide display library (e.g., FliTrx™) is screened for the binding to the above transfectants by panning. After several rounds of screening, positive clones are sequenced. Full- length polypeptides are identified by colony hybridization of a T cell cDNA library using oligonucleotide or PCR primers synthesized based on the peptide sequence. Biochemical Approach. Total cell extracts or membrane fractions prepared from a T cell line are applied onto an affinity column conjugated with soluble human dendritic cell immunoreceptor. Molecules bound to the column (i.e., putative ligands) are eluted by changing the pH or washing with EDTA or carbohydrates. The eluents are purified by conventional column chromatography and HPLC and then examined for amino acid sequences. cDNA encoding these ligands is cloned by colony hybri- dization of a T cell cDNA library using oligonucleotide or PCR primers synthesized based on the revealed amino acid sequence. EXAMPLE 6 Identification of a test compound which decreases dendritic cell immunoreceptor activity A test compound is administered to a culture of human cells transfected with a dendritic cell immunoreceptor expression construct and incubated at 37°C for 10 to 45 minutes. A culture of the same type of cells which have not been transfected is incubated for the same time without the test compound to provide a negative control. Binding of ligands identified as described above to human dendritic cell immuno- receptors is assayed in the presence and absence of the test compound. A test compound which decreases the binding of a ligand to the dendritic cell immunoreceptor is identified as an inhibitor of dendritic cell immunoreceptor activity. EXAMPLE 7 Treatment of asthma with a reagent that specifically binds to a dendritic cell immunoreceptor gene product Synthesis of antisense dendritic cell immunoreceptor oligonucleotides comprising at least 11 contiguous nucleotides selected from the complement of SEQ ID NO: 1 or 15 is performed on a Pharmacia Gene Assembler series synthesizer using the phos- phoroamidite procedure (Uhlmann et al, Chem. Rev. 90, 534-83, 1990). Following assembly and deprotection, oligonucleotides are ethanol-precipitated twice, dried, and suspended in phosphate-buffered saline (PBS) at the desired concentration. Purity of these oligonucleotides is tested by capillary gel electrophoreses and ion exchange HPLC. Endotoxin levels in the oligonucleotide preparation are determined using the Limulus Amebocyte Assay (Bang, Biol Bull. (Woods Hole, Mass.) 105, 361-362, 1953). An aqueous composition containing the antisense oligonucleotides is administered to the patient by inhalation. Severity of asthma is monitored over a period of days or weeks by noting changes in patients' asthmatic symptoms, measuring lung function, or measuring changes in markers of lung inflammation such as numbers of inflammatory cells or concentrations of inflammatory mediators in fluid sampled from patients' lungs by bronchoalveolar lavage. Asthma severity is reduced due to dendritic cell immunoreceptor activity. EXAMPLE 8 In vivo validation of novel compounds 1. Tests for activity of T cells are used to evaluate agents that modulate the expression or activity of costimulatory molecules-cytokines, cytokine receptors, signalling molecules, or other molecules involved in T cell activation Mouse anti-CD '-induced cytokine production model: BALB/c mice are injected with a single intravenous injection of 10 μg of 145- 2C11 (purified hamster anti-mouse CD3 monoclonal antibodies, PHARMINGEN). Compound is administered intraperitoneally 60 min prior to the anti-CD3 mAb injection. Blood is collected 90 min after the antibody injection. Serum is obtained by centrifugation at 3000 r.p.m. for 10 min. Serum levels of cytokines, such as IL-2 and IL-4, or other secreted molecules are determined by an ELISA. Proteins which regulate the CD3 downstream signaling can be evaluated in this model. 2. Tests for activity of B cells are used to evaluate agents that modulate the expression or activity of the B cell receptor, signaling molecules, or other molecules involved in B cell activation/immunoglobulin class switching Mouse anti-lgD induced IgE production model: BALB/c mice are injected intravenously with 0.8 mg of purified goat anti- mouse IgD antibody or PBS (defined as day 0). Compound is administered intraperitoneally from day 0 to day 6. On day 7 blood is collected and serum is obtained by centrifugation at 3000 r.p.m. for 10 min. Serum levels of total IgE are determined by YAMASA's ELISA kit and other Ig subtypes are measured by an Ig ELISA KIT (Rougier Bio-tech's, Montreal, Canada). Proteins that regulate IgD downstream signaling and Ig class switching can be evaluated. 3. Tests for activity of monocytes/macrophages are used to evaluate agents that modulate the expression or activity of signalling molecules, transcription factors. Mouse LPS-induced TNF-a production model: Compound is administered to BALB/c mice by intraperitoneal injection and one hour later the mice given LPS (200 μg/mouse) by intraperitoneal injection. Blood is collected 90 minutes after the LPS injection and plasma is obtained. TNF-α concentration in the sample is determined using an ELISA kit. Proteins that regulate downstream effects of LPS stimulation, such as NF- B activation, can be evaluated. Tests for activity of eosinophils are used to evaluate agents that modulate the expression or activity of the eotaxin receptor, signaling molecules, cyto- skeletal molecules, or adhesion molecules. Mouse eotaxin-induced eosinophilia model: BALB/c mice are injected intradermally with a 2.5 ml of air on days -6 and - 3 to prepare an airpouch. On day 0, compound is administered intraperitoneally, and 30 minutes later, IL-5 (300 ng/mouse) is injected intravenously. After an additional 30 -minutes, eotaxin is injected (3 μg/mouse, i.d.). Four hours after the eotaxin injection, leukocytes in the airpouch exudate are collected and the number of total cells is counted. Differential cell counts in the exudate are performed by staining with May- Grunwald Gimsa solution. Proteins that regulate signaling by the eotaxin receptor or regulate eosinophil trafficking can be evaluated. Passive cutaneous anaphylaxis (PCA) test in rats 6 Weeks old male Wistar rats are sensitized intradermally (i.d.) on their shaved backs with 50 μl of 0.1 μg/ml mouse anti-DNP IgE monoclonal antibody (SPE-7) under a light anesthesia. After 24 hours, the rats are challenged intravenously with 1 ml of saline containing 0.6 mg DNP-BSA (30) (LSL CO., LTD) and 0.005 g of Evans blue. Compounds are injected intraperitoneally (i.p.) 0.5 hr prior to antigen injection. Rats without the sensitization, challenge, and compound treatment are used as a control and rats with sensitization, challenge and vehicle treatment are used to determine the value without inhibition. Thirty minutes after the challenge, the rats are sacrificed, and the skin of the back is removed. Evans blue dye in the skin is extracted in formamide overnight at 63°C. Absorbance at 620 nm is then measured to obtain the optical density of the leaked dye. Percent inhibition of PCA with a compound is calculated as follows: % inhibition = {(mean vehicle value - sample value)/(mean vehicle value — mean control value)} x 100 Proteins that regulate mast cell degranulation, vascular permeability, or receptor antagonists against histamine receptors, serotonin receptors, or cysteinyl leukotriene receptors can be evaluated. 6. Anaphylactic bronchoconstriction in rats 6 Weeks old male Wistar rats are sensitized intravenously (i.v.) with 10 μg mouse anti-DNP IgE, SPE-7, and 1 days later, the rats are challenged intravenously with 0.3 ml of saline containing 1.5 mg DNP-BSA (30) under anesthesia with urethane (1000 mg/kg, i.p.) and gallamine (50 mg/kg, i.v.). The trachea is cannulated for artifical respiration (2 ml/stroke, 70 strokes/min). Pulmonary inflation pressure (PIP) is recorded thruogh a side-arm of the cannula connected to a pressure transducer. Changes in PIP reflect a change of both resistance and compliance of the lungs. To evaluate a compound, the compound is given i.v. 5 min before challenge. Proteins that regulate mast cell degranulation, vascular permeability or receptor antagonists against histamine receptors, serotonin receptors, or cysteinyl leukotriene receptors can be evaluated. Proteins that regulate the contraction of smooth muscle can be also evaluated. T cell adhesion to smooth muscle cells or endothelial cells A purified population of T cells is prepared by ficoll density centrifugation followed by separation on a nylon wool column, resetting with sheep red blood cells, or using magnetic beads coated with antibodies. The T cells are activated with mitogen for 36 to 42 hours and labeled with 3 H-thymidine during the last 16 hours of the activation. Airway smooth muscle cells or bronchial microvascular endothelial cells are obtained from lung transplant tissue, from bronchus resections from cancer patients, from cadavers, or as cell lines from commercial sources. If fresh tissue is used as the source of cells, the smooth muscle cells and endothelial cells can be isolated from tissue by dissection followed by digestion for 30-60 minutes in a solution containing 1.1 mM ethyleneglycol-bis-(beta-aminoethylether)-N,N,N',N'-tetraacetic acid, 640 U/ml collagenase, 10 mg/ml soybean trypsin inhibitor, and 10 U/ml elastase. The smooth muscle cells or endothelial cells are grown in 24-well tissue culture dishes until confluent and then treated with a test compound and inflammatory mediators, such as TNF-α for 24 hours. To measure adhesion, 6 x 10 5 T cells are added per well and allowed to adhere for one hour at 37°C. Nonadherent cells are removed by washing six times gently with medium. Finally, the remaining adherent cells are lysed by adding 300 μl 1% Triton-X 100 in PBS to each well and quantitating the radioactivity in a scintillation counter. The percent binding is calculated as counts recovered from adherent cells/total input counts x 100% REFERENCES Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory, 1988. Ariizumi, Kitajima, Bergstresser, Takashima, Eur. J. Inmunol., 25:2137-2141, 1995. Beaudet, Am. J. Hum. Gen., 37:386-406, 1985. Bittner et al., Methods in Enzymol., 153:516-544, 1987. Bradley et al., Cunent Topics in Developmental Biology, 20:357-371, 1986. Brutlag et al, CABIOS, 6:237-245, 1990. Caceres-Dittmar, Ariizumi, Xu, Tapia, Bergstresser, Takashima, Photochem. Photobiol., 62:176-183, 1995. Campbell, In: Monoclonal Antibody Technology, Laboratory Techniques In Biochemistry and Molecular Biology, Burden and Von Knippenberg, Amsterdam, Elseview, Vol. 13, pp 75-83, 1984. Caouto, Christian, Peterson, Ceriani, Cancer Research (supp.), 55:5973s-5977s, 1995. Capaldi et al., Biochem. Biophys. Res. Comm., 76:425 1977. Caux, Massacrier, Vanbervliet et al, J. Exp. Med., 180:1263-1272, 1994. Chou and Fasman, Adv. Enzymol. Relat. Areas Mol. Biol, 47:45-148, 1978a. Chou and Fasman, Ann. Rev. Biochem., 47:251-276, 1978b. Chou and Fasman, Biophys. J., 26:367-384, 1979. Chou and Fasman, Biochemistry, 13(2):222-245, 1974a. Chou and Fasman, Biochemistry, 13(2):211-222, 1974b. Co, Baker, Bednavik, Janzek, Noruda Mayer, Plot, Stumper, Vesquez, Queen, Loibner, Cancer Research, 56: 1118-1 125, 1996. Co, Avdalovic, Caron, Avdalovic, Scheinberg, Queen, J. Immunology, 138: 1149- 1154, 1992. Colbene-Garapin et al., J. Mol. Biol., 150:1, 1981. Enk and Katz, Proc. Natl. Acad. Sci. USA, 89;1398-1402, 1992. Ezekomitz et al., 1990 Ezekomitz et al., 1991. Fetrow and Bryant, Biotechnology, 11:479-483, 1993. Flam, JOURNAL, VOL:PAGES?, 1994. Gefter et al., Somatic Cell Genet., 3:231-236, 1977 Goding, In: Monoclonal Antibodies: Principles and Practice, 2d ed., Orlando, Fla. 5 Academic Press, pp. 60-61, 65-66, 71-74, 1986. Hess et al., J. Adv. Enzyme Reg., 7:149, 1968. Heufler, Topar, Koch, et al., J. Exp. Med., 176:1221-1226, 1992. Hitzeman et al., J. Biol. Chem., 255:2073, 1980. Hogan et al., Manipulating the Mouse Embryo: A Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1986. Holland et al., Biochemistry, 17:4900, 1978. Hoover et al., (eds). "Remington's Pharmaceutical Sciences," 15th Ed., pp. 1035- 1038 and 1570-1580, Mark Publishing Co., Barton, Pa., 1975. Hopp, U.S. Pat. No. 4,554,101 Inaba, Swiggard, Inaba et al., Cell. Inmunol., 163:148-156, 1995. Jameson and Wolf, Comput. Appl. Biosci., 4(1): 181-186, 1988. Jiang, Swiggard, Heufler et al., Nature, 375:151-155, 1995. Johnson et al., Biotechnology and Pharmacy, Pezzuto et al., eds., Chapman and Hall, New York, 1993. Jones, Genetics, 85:12, 1977. Kery, 1991. Kingsman et al., JOURNAL, VOL:PAGES?, 1979. Kijimoto-Ochiai et al., 1994. Kitajima, Ariizumi, Mohamadzadeh, Edelbaum, Bergstresser, Takashima, J. Immunol., 155:3794-3800, 1995. Kohler and Milstein, Eur. J. Immunol., 6:511-519, 1976. Kholer and Milstein, Nature, 256:495-497, 1975. Kyte and Doolittle, J. Mol. Biol., 157: 105-132, 1982. Lovell-Badge, In: Teratocarcinomas and Embryonic Stem Cells: A Practical Approach, E. J. Robertson, ed., IRL Press, Washington D.C., 1987. Lowry et al., Cell, 22:817, 1980. Matsue, Cruz, Bergstresser, Takashima, J. Invest. DermatoL, 99:537-541, 1992. Mohamadzadeh, Poltorak, Bergstresser, Beutler, Takashima, J. Immunol., 156:3102- 3106, 1996. Mulligan et al., Proc. Natl. Acad. Sci. USA, 78:2072, .1981, Nakamura et al., "Enzyme Immunoassays: Heterogeneous and Homogeneous Systems," Chapter 27, 1987. O'Hare et al., Proc. Natl. Acad. Sci. USA, 78; 1527, 1981. Oldenburg et al., 1992. Reid et al., 1994. Robertson, Teratocarcinomas and Embryonic Stem Cells: A Practical Approach, E. J. Robertson, ed., IRL Press, Washington D.C., 1987. Sallusto, Cella, Danieli, Lanzavecchi, J. Exp. Med., 182:389-400, 1995. Sambrook, Fritsch, Maniatis, Molecular Cloning, A Laboratory Manual, 2nd ed., 1989. Sancar, Valdineso, Borders, Yao, Raval, Madan, Sreepatni, Shimoyami, Steiger, Visscher, Diagnostic Molecular Patholgy, 4:266-273, 1995. Santene et al., Gene, 30: 147, 1984. Schreiber, Kilgus, Payer et al., J. Immunol., 149:3525-3534, 1992. Spiess, Biochemistry, 29:10009-10018, 1990. Stahl, Current Opinion in Immunology, 4:49-52, 1992. Steinman and Swanson, J. Exp. Med, 182:283-288, 1995. Steinman, Ann. Rev. Immunol., 9:271-296, 1991. Steinman, Inaba, Schuler, In: The Immune Functions of Epidermal Langerhans Cells, (ed. Heidrun Moll), R. G. Landes Company, Austin, Tex., 1-19, 1995. Stinchcomb et al., Nature, 282:39, 1979. Szybalska et al., Proc. Natl. Acad. Sci. USA, 48:2026, 1962. Takashima, Edelbaum, -Kitajima et al., J. Immunol., 154: 5128-5135, 1995. Tschemper et al., Gene, 10:157, 1980. Vassa et al., 1994. Vercelli et al., 1989. Weinberger et al., Science, 228:740-742, 1985. Wigler et al., Cell, 11:223, 1977. Wigler et al., Proc. Natl. Acad. Sci. USA, 77:3567, 1980. Witmer-Pack, Swiggard, Mirza, Inaba, Steinman, Cell. Immunol., 163:157-162, 1995. Wolf et al., Comput. Appl. Biosci., 4(1): 187-191, 1988. Xu, Ariizumi, Caceres-Dittnar et al., J. Immunol., 154:2697-2705, 1995. Xu, Ariizumi, Edelbaum, Bergstresser, Takashima, Eur. J. Immunol., 25:1018-1024, 1995.

Claims: CLAIMS 1. An isolated polynucleotide encoding a dendritic cell immunoreceptor polypeptide and being selected from the group consisting of: a) a polynucleotide encoding a dendritic cell immunoreceptor polypeptide comprising an amino acid sequence selected form the group consisting of: amino acid sequences which are at least about 30% identical to the amino acid sequence shown in SEQ ID NO: 2; the amino acid sequence shown in SEQ ID NO: 2; amino acid sequences which are at least about 30% identical to the amino acid sequence shown in SEQ ID NO: 15; and the amino acid sequence shown in SEQ ID NO: 15; b) a polynucleotide comprising the sequence of SEQ ID NO: 1 or 14; c) a polynucleotide which hybridizes under stringent conditions to a polynucleotide specified in (a) and (b); d) a polynucleotide the sequence of which deviates from the polynucleotide sequences specified in (a) to (c) due to the degeneration of the genetic code; and e) a polynucleotide which represents a fragment, derivative or allelic variation of a polynucleotide sequence specified in (a to (d). 2. An expression vector containing any polynucleotide of claim 1. 3. A host cell containing the expression vector of claim 2. 4. A substantially purified dendritic cell immunoreceptor polypeptide encoded by a polynucleotide of claim 1. 5. A method for producing a dendritic cell immunoreceptor polypeptide, wherein the method comprises the following steps: a) culturing the host cell of claim 3 under conditions suitable for the expression of the dendritic cell immunoreceptor polypeptide; and b) recovering the dendritic cell immunoreceptor polypeptide from the host cell culture. 6. A method for detection of a polynucleotide encoding a dendritic cell immunoreceptor polypeptide in a biological sample comprising the following steps: a) hybridizing any polynucleotide of claim 1 to a nucleic acid material of a biological sample, thereby forming a hybridization complex; and b) detecting said hybridization complex. 7. The method of claim 6, wherein before hybridization, the nucleic acid material of the biological sample is amplified. 8. A method for the detection of a polynucleotide of claim 1 or a dendritic cell immunoreceptor polypeptide of claim 4 comprising the steps of: contacting a biological sample with a reagent which specifically interacts with the polynucleotide or the dendritic cell immunoreceptor polypeptide. 9. A diagnostic kit for conducting the method of any one of claims 6 to 8. 10. A method of screening for agents which decrease the activity of a dendritic cell immunoreceptor, comprising the steps of: contacting a test compound with any dendritic cell immunoreceptor polypeptide encoded by any polynucleotide of claiml; detecting binding of the test compound to the dendritic cell immunoreceptor polypeptide, wherein a test compound which binds to the polypeptide is identified as a potential therapeutic agent for decreasing the activity of a dendritic cell immunoreceptor. 1 1. A method of screening for agents which regulate the activity of a dendritic cell immunoreceptor, comprising the steps of: contacting a test compound with a dendritic cell immunoreceptor polypeptide encoded by any polynucleotide of claim 1; and detecting a dendritic cell immunoreceptor activity of the polypeptide, wherein a test compound which increases the dendritic cell immunoreceptor activity is identified as a potential therapeutic agent for increasing the activity of the dendritic cell immunoreceptor, and wherein a test compound which decreases the dendritic cell immunoreceptor activity of the polypeptide is identified as a potential therapeutic agent for decreasing the activity of the dendritic cell immunoreceptor. 12. A method of screening for agents which decrease the activity of a dendritic cell immunoreceptor, comprising the steps of: contacting a test compound with any polynucleotide of claim 1 and detecting binding of the test compound to the polynucleotide, wherein a test compound which binds to the polynucleotide is identified as a potential therapeutic agent for decreasing the activity of dendritic cell immunoreceptor. 13. A method of reducing the activity of dendritic cell immunoreceptor, comprising the steps of: contacting a cell with a reagent which specifically binds to any poly- nucleotide of claim 1 or any dendritic cell immunoreceptor polypeptide of claim 4, whereby the activity of dendritic cell immunoreceptor is reduced. 14. A reagent that modulates the activity of a dendritic cell immunoreceptor polypeptide or a polynucleotide wherein said reagent is identified by the method of any of the claim 10 to 12. 15. A pharmaceutical composition, comprising: the expression vector of claim 2 or the reagent of claim 14 and a pharma- ceutically acceptable carrier. 16. Use of the expression vector of claim 2 or the reagent of claim 14 for the preparation of a medicament for modulating the activity of a dendritic cell immunoreceptor in a disease. 17. Use of claim 16 wherein the disease is cancer, asthma, obesity, diabetes, a CNS disorder, or a cardiovascular disorder. 18. A cDNA encoding a polypeptide comprising the amino acid sequence shown in SEQ ID NO; 2 or 15. 19. The cDNA of claim 18 which comprises SEQ ID NO: 1 or 14. 20. The cDNA of claim 18 which consists of SEQ ID NO: 1 or 14. 21. An expression vector comprising a polynucleotide which encodes a polypeptide comprising the amino acid sequence shown in SEQ ID NO: 2 or 15. 22. The expression vector of claim 21 wherein the polynucleotide consists of SEQ ID NO: 1 or 14. 23. A host cell comprising an expression vector which encodes a polypeptide comprising the amino acid sequence shown in SEQ ID NO: 2 or 15. 24. The host cell of claim 23 wherein the polynucleotide consists of SEQ ID NO: 1 or 14. 25. A purified polypeptide comprising the amino acid sequence shown in SEQ ID NO: 2 or 15. 26. The purified polypeptide of claim 25 which consists of the amino acid sequence shown in SEQ ID NO: 2 or 15. 27. A fusion protein comprising a polypeptide having the amino acid sequence shown in SEQ ID NO: 2 or 15. 28. A method of producing a polypeptide comprising the amino acid sequence shown in SEQ ID NO: 2 or 15, comprising the steps of: culturing a host cell comprising an expression vector which encodes the polypeptide under conditions whereby the polypeptide is expressed; and isolating the polypeptide. 29. The method of claim 28 wherein the expression vector comprises SEQ ID NO: l or 14. 30. A method of detecting a coding sequence for a polypeptide comprising the amino acid sequence shown in SEQ ID NO: 2 or 15, comprising the steps of: hybridizing a polynucleotide comprising 11 contiguous nucleotides of SEQ ID NO: 1 or 14 to nucleic acid material of a biological sample, thereby forming a hybridization complex; and detecting the hybridization complex. 31. The method of claim 30 further comprising the step of amplifying the nucleic acid material before the step of hybridizing. 32. A kit for detecting a coding sequence for a polypeptide comprising the amino acid sequence shown in SEQ ID NO: 2 or 15, comprising: a polynucleotide comprising 11 contiguous nucleotides of SEQ ED NO: 1 or 14; and instructions for the method of claim 30. 33. A method of detecting a polypeptide comprising the amino acid sequence shown in SEQ ID NO: 2 or 15, comprising the steps of: contacting a biological sample with a reagent that specifically binds to the polypeptide to form a reagent-polypeptide complex; and detecting the reagent-polypeptide complex. 34. The method of claim 33 wherein the reagent is an antibody. 35. A kit for detecting a polypeptide comprising the amino acid sequence shown in SEQ ID NO: 2 or 15, comprising: an antibody which specifically binds to the polypeptide; and instructions for the method of claim 33. 36. A method of screening for agents which can modulate the activity of a human dendritic cell immunoreceptor, comprising the steps of: contacting a test compound with a polypeptide comprising an amino acid sequence selected from the group consisting of: (1) amino acid sequences which are at least about 30% identical to the amino acid sequence shown in SEQ ED NO: 2 or 15 and (2) the amino acid sequence shown in SEQ ID NO: 2 or 15; and detecting binding of the test compound to the polypeptide, wherein a test compound which binds to the polypeptide is identified as a potential agent for regulating activity of the human dendritic cell immunoreceptor. 37. The method of claim 36 wherein the step of contacting is in a cell. 38. The method of claim 36 wherein the cell is in vitro. 39. The method of claim 36 wherein the step of contacting is in a cell-free system. 40. The method of claim 36 wherein the polypeptide comprises a detectable label. 41. The method of claim 36 wherein the test compound comprises a detectable label. 42. The method of claim 36 wherein the test compound displaces a labeled ligand which is bound to the polypeptide. 43. The method of claim 36 wherein the polypeptide is bound to a solid support. 44. The method of claim 36 wherein the test compound is bound to a solid support. 45. A method of screening for agents which modulate an activity of a human dendritic cell immunoreceptor, comprising the. steps of: contacting a test compound with a polypeptide comprising an amino acid sequence selected from the group consisting of: (1) amino acid sequences which are at least about 30% identical to the amino acid sequence shown in SEQ ID NO: 2 or 15 and (2) the amino acid sequence shown in SEQ ID NO: 2 or 15; and detecting an activity of the polypeptide, wherein a test compound which increases the activity of the polypeptide. is identified as a potential agent for increasing the activity of the human dendritic cell immunoreceptor, and wherein a test compound which decreases the activity of the polypeptide is identified as a potential agent for decreasing the activity of the human dendritic cell immunoreceptor. 46. The method of claim 45 wherein the step of contacting is in a cell. 47. The method of claim 45 wherein the cell is in vitro. 48. The method of claim 45 wherein the step of contacting is in a cell-free system. 49. A method of screening for agents which modulate an activity of a human dendritic cell immunoreceptor, comprising the steps of: contacting a test compound with a product encoded by a polynucleotide which comprises the nucleotide sequence shown in SEQ ID NO: 1 or 14; and detecting binding of the test compound to the product, wherein a test compound which binds to the product is identified as a potential agent for regulating the activity of the human dendritic cell immunoreceptor. 50. The method of claim 49 wherein the product is a polypeptide. 51. The method of claim 49 wherein the product is RNA. 52. A method of reducing activity of a human dendritic cell immunoreceptor, comprising the step of: contacting a cell with a reagent which specifically binds to a product encoded by a polynucleotide comprising the nucleotide sequence shown in SEQ ID NO: 1 or 14, whereby the activity of a human dendritic cell immunoreceptor is reduced. 53. The method of claim 52 wherein the product is a polypeptide. 54. The method of claim 53 wherein the reagent is an antibody. 55. The method of claim 52 wherein the product is RNA. 56. The method of claim 55 wherein the reagent is an antisense oligonucleotide. 57. The method of claim 56 wherein the reagent is a ribozyme. 58. The method of claim 52 wherein the cell is in vitro. 59. The method of claim 52 wherein the cell is in vivo. 60. A pharmaceutical composition, comprising: a reagent which specifically binds to a polypeptide comprising the amino acid sequence shown in SEQ ID NO: 2 or 15; and a pharmaceutically acceptable carrier. 61. The pharmaceutical composition of claim 60 wherein the reagent is an antibody. 62. A pharmaceutical composition, comprising: a reagent which specifically binds to a product of a polynucleotide comprising the nucleotide sequence shown in SEQ ID NO: 1 or 14; and a pharmaceutically acceptable earner. 63. The pharmaceutical composition of claim 62 wherein the reagent is a ribozyme. 64. The pharmaceutical composition of claim 62 wherein the reagent is an antisense oligonucleotide. 65. The pharmaceutical composition of claim 62 wherein the reagent is an antibody. 66. A pharmaceutical composition, comprising: an expression vector encoding a polypeptide comprising the amino acid sequence shown in SEQ ID NO: 2 or 15; and a pharmaceutically acceptable carrier. 67. The pharmaceutical composition of claim 66 wherein the expression vector comprises SEQ ID NO: 1 or 14. 68. A method of treating a dendritic cell immunoreceptor dysfunction related disease, wherein the disease is selected from cancer, asthma, obesity, diabetes, a CNS disorder, or a cardiovascular disorder comprising the step of: administering to a patient in need thereof a therapeutically effective dose of a reagent that modulates a function of a human dendritic cell immunoreceptor, whereby symptoms of the dendritic cell immunoreceptor dysfunction related disease are ameliorated. 69. The method of claim 68 wherein the reagent is identified by the method of claim 36. 70. The method of claim 68 wherein the reagent is identified by the method of claim 45. 71. The method of claim 68 wherein the reagent is identified by the method of claim 49.

Inventors: SMOLYAR ALEX, SMOLYAR, ALEX
Applicants: BAYER AG, SMOLYAR ALEX, BAYER AKTIENGESELLSCHAFT, SMOLYAR, ALEX
Application year: 2001
Main classification: C07K14
IPC codes: A61K38, A61K39, A61K45, A61K48, A61P3, A61P7, A61P9, A61P11, A61P25, A61P35, A61P37, A61P43, C07K14, C07K19, C12N1, C12N5, C12N9, C12N15, C12P21, C12Q1, G01N33