LECTOMEDIN MATERIALS AND METHODS

Abstract: Disclosed are novel seven transmembrane receptor polypeptides having characteristic extracellular structure including lectin-binding, olfactomedin-like and mucin-like domains.

Description: LECTOMEDIN MATERIALS AND METHODS This application is a continuation-in-part of U.S. Patent Application Serial No: 09/262,537, filed March 4, 1999, which is pending and claims priority of U.S. Provisional Application Serial No: 60/076,782, filed March 4, 1998. BACKGROUND OF THE INVENTION G-protein coupled receptors (GPCRs) are proteins that interact with G- proteins to transmit an intracellular signal. Upon ligand binding, GPCRs trigger the hydrolysis of GTP to GDP by G-protein subunits; GTP hydrolysis is accompanied by a switch from activity to inactivity. It is estimated that there are roughly 1,000 GPCRs [Clapham, Nature 379:297-299 (1996)] and all characterized to date include a seven transmembrane domain that anchors the receptor to the cell. GPCRs include receptors for opiates, adrenaline, histamine, polypeptide hormones, and photons, among other ligands. These receptors are coupled to a wide variety of cellular second messenger pathways including, for example, pathways that alter intracellular calcium concentrations and cAMP levels. Among the various GPCRs identified, CD97 appears to be representative of a sub-family of proteins which effect cellular adhesion [McKnight, et al, Immunol Today 77:283-287(1996)]. CD97 and related receptors are unique in that their structure includes a transmembrane domain that directly links a cytoplasmic domain that participates in GTP hydrolysis with extracellular protein binding domains that specifically participate in cell-cell adhesion. The extracellular, amino terminal region of CD97 includes numerous cell-cell adhesive motifs, including multiple epidermal growth factor-like (EGF-like) repeats and an integrin binding site [Hamann J, et al., Immunol 155: 1942-1950 (1996); Gray, et al, J. Immunol 757:5438-5447 (1996)]. Proteins that contain EGF-like repeats have been shown to be involved in cell adhesion events [Campbell, et al, Curr. Opin. Struct. Biol. 3:385-392 (1993); Rao.et al, Cell 82:121-141 (1995)], and consistent with this observation, heterologous expression of CD97 in COS cells elicits homotypic cell aggregation that can be blocked in the presence of anti-CD97 monoclonal antibodies [Hamann, et al, J. Exp. Med. 184:1185-1189 (1996)]. CD97 and related proteins have been referred to as the EGF-7TM subfamily of seven transmembrane receptors [McKnight and Gordon, Immunol. Today 77:283-2887 (1996)]. Ligands identified for CD97 include members ofthe integrin family of cell surface adhesion receptors. Various integrins recognize and interact with their cognate ligands through a trimeric amino acid sequence of arginine-glycine-aspartic acid (denoted RGD in the single letter amino acid code) [D'Souza, et al, Trends Biochem. Sci., 7 :246-250 (1991)] and this sequence has been identified in the extracellular region of CD97, between the EGF-like repeats and the transmembrane domain. CD97 has been shown to undergo post-translational proteolytic processing which results in an extracellular (and potentially soluble) alpha subunit and a smaller, integral membrane beta subunit [Gray, et al, J. Immunol. 757:5438-5447 (1996)]. The two subunits are associated in a non-covalent manner and the alpha subunit is held at the cell surface through its interaction with the beta subunit. The role of proteolysis is unclear, but it may be a mechanism for receptor down-regulation which is common among proteins, such as selectins and intercellular adhesion molecules (ICAMs), that participate in cell adhesion. Other members ofthe CD97 sub-family of GPCRs have been identified by amino acid sequence and structural homology and include human EMR1, HE6, BAH, the calcium-independent receptor of latrotoxin (CURL), latrophilin, and proteins encoded by the Caenorhabditis elegans open reading frames designated B0457.1 and B0286.2 [Baud N, et al, Genomics 26:334-344 (1995); McKnight, etal, J. Biol Chem. 277:486-489 (1996); Krasnoperov, et al, Neuron 75:925-937 (1997); Lelianova, et al, J. Biol. Chem. 272:21504-21508 (1997); Davletov, et al, J. Biol. Chem. 277:23239-23245 (1996); Νishimori, et al, Oncogene 75:2145-2150 (1997)]. EMR1, and its murine homoiog F4/80, are macrophage-specific in expression and structurally related to CD97 in that they contain multiple extracellular EGF-like repeats, a rod-like stalk region, and the characteristic transmembrane domain of GPCRs [Baud N, et al, Genomics 26:334-344 (1995); McKnight, et al, J. Biol Chem. 277:486-489 (1996)]. No ligands have been identified for EMR-1 and it is uncertain if the protein undergoes post-translational proteolytic processing. CIRL [Krasnoperov, et al. Neuron 75:925-937 (1997); Lelianova, et al, J. Biol. Chem. 272:21504-21508 (1997); Davletov, et al, J. Biol Chem. 277:23239-23245 (1996)] is believed to be expressed specifically in the central nervous system at neuronal presynaptic terminals and, like CD97, undergoes proteolytic cleavage resulting in an extracellular alpha subunit in non-covalent association with an integral membrane seven-transmembrane beta subunit. Cleavage of latrophilin is believed to occur at a Ser-His-Leu/Thr-Asn-Phe site that is conserved in CD97 [Krasnoperov, et al, Neuron 75:925-937 (1997)]. CIRL has been shown to bind latrotoxin, a component of black widow spider venom, in the 0.5 to 1.0 nM range, and binding ofthe ligand to CIRL expressed in bovine chromaffin cells has been shown to result in exocytosis, a hallmark of toxin binding [Krasnoperov, et al, Neuron 75:925-937 (1997)]. Alpha latrotoxin binding has also been demonstrated at neuromuscular motor endplates, and this interaction elicits explosive secretory granule release of acetylcholine from presynaptic granules, resulting in muscle paralysis characteristic ofthe spider's bite [Petrenko, et al, F.E.B.S. Letts. 525:81-85 (1993)]. It is unclear, however, if the peripheral toxin effects result from binding to CIRL or some other related protein. Thus there exists a need in the art to identify and characterize other members ofthe CD97-like family of GPCRs, in particular human receptors which participate in cellular adhesion and those that participate in cytoplasmic metabolic pathways modulated by extracellular signals. Identification of CD97-like receptors can permit identification and diagnosis of disease states which arise from aberrant signaling by the receptor, as well as disease states that arise from aberrant expression ofthe receptor itself. SUMMARY OF THE INVENTION The present invention provides purified and isolated human seven transmembrane receptor lectomedin polypeptides or fragments thereof, said polypeptides comprising extracellular lectin-binding, olfactomedin-like, and mucin-like domains. Mature lectomedin polypeptides are also provided wherein signal or leader sequences are cleaved. Preferred polypeptides ofthe invention comprise the amino acid sequence set out in SEQ ID NO: 2 or a fragment thereof, the amino acid sequence set out in SEQ ID NO: 4 or fragment thereof, the amino acid sequence set out in SEQ ID NO: 6 or fragment thereof, the amino acid sequence set out in SEQ ID NO: 70 or fragment thereof, or the amino acid sequence set out in SEQ ID NO: 80 or fragment thereof. The invention also provides polynucleotides encoding polypeptides of the invention. Preferred polynucleotides comprising the sequence set forth in SEQ ED NO: 1, SEQ ED NO: 3, SEQ ED NO: 5, SEQ ED NO: 69 and SEQ ED NO: 79. The invention also provide polynucleotides encoding a human lectomedin polypeptide selected from the group consisting ofthe polynucleotide set out in SEQ ED NO: 1, SEQ ED NO: 3, SEQ ED NO: 5, SEQ ED NO: 69 or SEQ ED NO: 79; b) a DNA which hybridizes under moderately stringent conditions to the non-coding strand ofthe polynucleotide of (a); and c) a DNA which would hybridize to the non-coding strand ofthe polynucleotide of (a) but for the redundancy ofthe genetic code. The invention also provides a lectomedin-encoding polynucleotide selected from the group consisting of : a) the polynucleotide set out in SEQ ED NO: 1, SEQ ED NO: 3, SEQ ED NO: 5, SEQ ED NO: 69 or SEQ ED NO: 79; b) a polynucleotide encoding the polypeptide set out in SEQ ED NO: 2, SEQ ED NO: 4, SEQ ED NO: 6, SEQ ED NO: 70 or SEQ ED NO: 80; and c) a polynucleotide that hybridizes to the polynucleotide of (a) or (b) under moderately or highly stringent conditions. Preferred polynucleotides ofthe invention are DNA molecules. Preferred DNA molecules are cDNA molecules and genomic DNA molecules. The invention also provides DNA which is a wholly or partially chemically synthesized. Antisense polynucleotide which specifically hybridizes with a polynucleotide ofthe invention are also comprehended. The invention also proved expression construct comprising the a polynucleotide ofthe invention, as well as host cells transformed or transfected with a polynucleotide or expression construct ofthe invention. The invention also provides polynucleotide ofthe invention operably linked to a heterologous promoter, and host cells polynucleotides operably linked to a heterologous promoter. The invention further provides methods for identifying a modulator of lectomedin binding to a binding partner comprising the steps of: a) measuring binding between lectomedin and the binding partner in the presence and absence of a test compound; and b) identifying the test compound as a modulator of lectomedin binding to the binding partner binding when a different level of lectomedin binding to the binding partner is detected in the presence ofthe test compound compared to' lectomedin binding the binding partner in the absence ofthe test compound. In a preferred method, the binding partner is selected from the group consisting of galectin- 3 (Mac-2); fibrinogen; immunoglobulin mu chain constant region; KIAA0445; hepatitis Delta antigen-interacting protein dip A; kinesin-related protein, KEF3C; G0/G1 regulatory switch protein G0S3 (FOSB); neuron-specific amyloid protein homologous to AMY; RANBPM; ADA3 -like protein that is part of the PC AF histone acetylase ® complex; and human genomic clone 18 A 13 (GenBank Accession No: AC007198) The invention also provides methods for modulating lectomedin binding to a binding partner comprising the step of contacting lectomedin or the binding partner with a modulator of lectomedin binding to the binding partner. Preferred methods ofthe invention include those wherein the modulator is an inhibitor and those wherein the modulator is an enhancer. Preferably, the binding partner is selected from the group consisting of galectin-3 (Mac-2); fibrinogen; immunoglobulin mu chain constant region; KIAA0445; hepatitis Delta antigen-interacting protein dip A; kinesin-related protein, KEF3C; G0/G1 regulatory switch protein G0S3 (FOSB); neuron-specific amyloid protein homologous to AMY; RANBPM; AD A3 -like protein that is part ofthe PCAF histone acetylase complex; and human genomic clone 18_A_13 (GenBank® Accession No: AC007198) The invention further provides methods to ameliorate a disease state associated with lectomedin binding to a binding partner comprising the step of administering to an individual in need thereof an effective amount of a modulator of lectomedin binding to the binding partner. In preferred methods, the binding partner is selected from the group consisting of galectin-3 (Mac-2); fibrinogen; immunoglobulin mu chain constant region; KIAA0445; hepatitis Delta antigen-interacting protein dipA; kinesin-related protein, KEF3C; G0/G1 regulatory switch protein G0S3 (FOSB); neuron-specific amyloid protein homologous to AMY; RANBPM; ADA3-like protein that is part ofthe PCAF histone acetylase complex; and human genomic clone ® 18 A 13 (GenBank Accession No: AC007198). In one aspect, methods ofthe invention include those wherein the modulator inhibits binding between lectomedin and the binding partner. In another aspect, the method utilizes a modulator that enhances binding between lectomedin and the binding partner. In a most preferred method, the binding partner is galectin-3 and the disease state is selected from the group consisting of atherosclerosis, restenosis or vascular disease. In another aspect, the invention provides methods for producing a human lectomedin polypeptide comprising the steps of: a) growing the host cell ofthe invention under conditions appropriate for expression ofthe lectomedin polypeptide and b) isolating the lectomedin polypeptide from the host cell or the medium of its growth. The invention also proved antibodies specifically immunoreactive with a polypeptide ofthe invention. Preferably, antibodies ofthe invention are monoclonal antibodies. The invention also provides cells, e.g. hybridomas, that produce antibodies ofthe invention. Anti-idiotype antibodies specifically immunoreactive with an antibody ofthe invention are also comprehended. The invention also provides methods to identify a specific binding partner compound of a lectomedin polypeptide comprising the steps of: a) contacting the lectomedin polypeptide with a compound under conditions which permit binding between the compound and the lectomedin polypeptide; b) detecting binding ofthe compound to the lectomedin polypeptide; and c) identifying the compound as a specific binding partner ofthe lectomedin polypeptide. Methods ofthe invention embrace specific binding partner that modulate activity ofthe lectomedin polypeptide. In one aspect, the compound inhibits activity ofthe lectomedin polypeptide, and in another aspect, the compound enhances activity ofthe lectomedin polypeptide. The invention also provides methods to identify a specific binding partner compound of a lectomedin polynucleotide comprising the steps of: a) contacting the lectomedin polynucleotide with a compound under conditions which permit binding between the compound and the lectomedin polynucleotide; b) detecting binding of the compound to the lectomedin polynucleotide; and c) identifying the compound as a specific binding partner ofthe lectomedin polynucleotide. Methods of the invention embrace specific binding partner that modulates expression of a lectomedin polypeptide encoded by the lectomedin polynucleotide. In one aspect, the compound inhibits expression ofthe lectomedin polypeptide, and in another aspect, the compound enhances expression of the lectomedin polypeptide. The invention also provides compounds identified by a method ofthe invention. In another aspect, the invention comprehends composition comprising the compound identified by a method ofthe invention, and a pharmaceutically acceptable carrier. The invention also provides use of a compound identified by a method ofthe invention for the preparation of a medicament to treat lectomedin related pathologies. The invention also provides for use of a lectomedin polypeptide in the preparation of a medicament for the treatment of a lectomedin related disorder. DETAILED DESCRIPTION OF THE INVENTION The present invention provides purified and isolated polypeptides and underlying polynucleotides for a novel family of transmembrane proteins designated lectomedins. The invention includes both naturally occurring and non-naturally occurring lectomedin polynucleotides and polypeptide products thereof. Naturally occurring lectomedin products include distinct gene and polypeptide species within the lectomedin family, including, for example, allelic variants, which are expressed within cells ofthe same animal, as well as corresponding species homologs expressed in cells of other animals. The invention further provides splice variants encoded by the same polynucleotide but which arise from distinct mRNA transcripts. Non-naturally occurring lectomedin products include variants ofthe naturally occurring products such as analogs, fragments, fusion (or chimeric) proteins, and lectomedin products having covalent modifications. The lectomedin family of proteins is distinguished from previously known seven transmembrane families of proteins in that the lectomedin proteins include at least one extracellular lectin binding-like domain and at least one extracellular olfactomedin domain. Unlike many other seven transmembrane proteins, the structure of proteins in the lectomedin family of proteins does not include EGF-like binding domains which effect cell/cell interactions. In a preferred embodiment, the invention provides polynucleotides comprising the sequences set forth in SEQ ED NOs: 1, 3, 5, 69, and 79. The invention also embraces polynucleotides encoding the amino acid sequences set out in SEQ ED NOs: 2, 4, 6, 70 and 80, as well as polynucleotides encoding mature polypeptides, wherein signal and or leader sequences are removed from the polypeptides as set out in SEQ ED NOs: 2, 4, 6, 70, and 80 . Presently preferred polypeptide ofthe invention comprises the amino acid sequences set out in SEQ ED NOs: 2, 4, 6, 70, and 80. The invention also provides expression constructs (or vectors) comprising polynucleotides ofthe invention, as well as host cells transformed, transfected, or electroporated to include a polynucleotide or expression construct of the invention. Methods to produce a polypeptide ofthe invention are also comprehended. The invention further provides antibodies, preferably monoclonal antibodies, specifically immunoreactive with a polypeptide ofthe invention, as well as cell lines, e.g., hybridomas, that secrete the antibodies. The present invention provides novel purified and isolated human polynucleotides (e.g., DNA sequences and RNA transcripts, both sense and complementary antisense strands, including splice variants thereof) encoding the human lectomedins. DNA sequences ofthe invention include genomic and cDNA sequences as well as wholly or partially chemically synthesized DNA sequences. Genomic DNA ofthe invention comprises the protein coding region for a polypeptide ofthe invention and includes allelic variants ofthe preferred polynucleotides ofthe invention. Genomic DNA ofthe invention is distinguishable from genomic DNAs encoding polypeptides other than lectomedin in that it includes the lectomedin coding region found in lectomedin cDNA ofthe invention. Genomic DNA ofthe invention can be transcribed into RNA, and the resulting RNA transcript may undergo one or more splicing events wherein one or more introns (i.e., non-coding regions) ofthe transcript are removed, or "spliced out." RNA transcripts that can be spliced by alternative mechanisms, and therefore be subjected to removal of different non-coding RNA sequences but still encode a lectomedin polypeptide, are referred to in the art as splice variants, which are embraced by the invention. Splice variants comprehended by the invention, therefore, are encoded by the same DNA sequences but arise from distinct mRNA transcripts. Allelic variants are known in the art to be modified forms of a wild type (predominant) gene sequence, the modification resulting from recombination during chromosomal segregation or exposure to conditions which give rise to genetic mutation. Allelic variants, like wild type genes, are inherently naturally occurring sequences (as opposed to non-naturally occurring variants which arise from in vitro manipulation). The invention also comprehends cDNA that is obtained through reverse transcription of an RNA polynucleotide encoding lectomedin, followed by second strand synthesis of a complementary strand to provide a double stranded DNA. "Chemically synthesized" as used herein and understood in the art, refers to polynucleotides produced by purely chemical, as opposed to enzymatic, methods. "Wholly" synthesized DNA sequences are therefore produced entirely by chemical means, and "partially" synthesized DNAs embrace those wherein only portions ofthe resulting DNA were produced by chemical means. Preferred DNA sequences encoding human lectomedin polypeptides are set out in SEQ ED NOs: 1, 3, 5, 69, and 79. The worker of skill in the art will readily appreciate that preferred DNAs ofthe invention comprise double stranded molecules, for example, the molecule having the sequence set forth in either SEQ ED NOs: 1, 3, 5, 69, or 79 along with the complementary molecule (the "non-coding strand" or "complement") having a sequence deducible from the sequence of SEQ ED NO: 1, 3, 5, 69, or 79 according to Watson-Crick base pairing rules for DNA. Also preferred are polynucleotides encoding the lectomedin polypeptides of SEQ ED NOs: 2, 4, 6, 70, and 80, and polynucleotides that hybridize thereto. The invention further embraces species, preferably mammalian, homologs ofthe human lectomedin DNA. Species homologs, also known in the art as orthologs, in general, share at least 35%, at least 40%, at least 45%, at least 50%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, or at least 99% homology with human DNA ofthe invention. Percent sequence "homology" with respect to polynucleotides ofthe invention is defined herein as the percentage of nucleotide bases in the candidate sequence that are identical to nucleotides in the lectomedin coding sequence after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity. The polynucleotide sequence information provided by the invention makes possible large scale expression, ofthe encoded polypeptide by techniques well known and routinely practiced in the art. Polynucleotides also permit identification and isolation of polynucleotides encoding related lectomedin polypeptides by well known techniques including Southern and/or Northern hybridization, and polymerase chain reaction (PCR), ligase chain reaction, as well as other amplification techniques. Examples of related polynucleotides include human and non-human genomic sequences, including allelic variants, as well as polynucleotides encoding polypeptides homologous to lectomedins and structurally related polypeptides sharing one or more biological, immunological, and/or physical properties of lectomedin. The disclosure of full length polynucleotides encoding lectomedin polypeptides makes readily available to the worker of ordinary skill in the art every possible fragment ofthe full length polynucleotides. The invention therefore provides fragments of lectomedin coding polynucleotides. Such fragments comprise at least 10 to 20, and preferably at least 15, consecutive nucleotides ofthe polynucleotide. The invention comprehends, however, fragments of various lengths. Preferably, fragment polynucleotides ofthe invention comprise sequences unique to the lectomedin coding polynucleotide sequence, and therefore hybridize under highly stringent or moderately stringent conditions only (i.e., "specifically") to polynucleotides encoding lectomedin, or lectomedin fragments thereof containing the unique sequence. Polynucleotide fragments of genomic sequences ofthe invention comprise not only sequences unique to the coding region, but also include fragments ofthe full length sequence derived from introns, regulatory regions, and/or other non-translated sequences. Sequences unique to polynucleotides ofthe invention are recognizable through sequence comparison to other known polynucleotides, and can be identified through use of alignment programs routinely utilized in the art, e.g., those made available in public sequence databases. The invention also provides fragment polynucleotides that are conserved in one or more polynucleotides encoding members of he lectomedin family of polypeptides. Such fragments include sequences characteristic ofthe family of lectomedin polynucleotides, and are also referred to as "signature sequences." The conserved signature sequences are readily discernable following simple sequence • comparison of polynucleotides encoding members ofthe lectomedin family. Fragments ofthe invention can be labeled in a manner that permits their detection, including radioactive and non-radioactive labeling. Fragment polynucleotides are particularly useful as probes for detection of full length or other fragment lectomedin coding polynucleotides. One or more fragment polynucleotides can be included in kits that are used to detect the presence of a polynucleotide encoding lectomedin, or used to detect variations in a polynucleotide sequence encoding lectomedin. The invention also embraces DNA sequences encoding lectomedin species which hybridize under moderately or highly stringent conditions to the non-coding strand, or complement, ofthe polynucleotide in SEQ ED NOs: 1, 3, 5, 69, and 79. DNA sequences encoding lectomedin polypeptides which would hybridize thereto but for the redundancy ofthe genetic code are further comprehended by the invention. The invention also provides polynucleotides that hybridize under moderate to high stringency conditions to polynucleotides encoding the lectomedin polypeptides in SEQ ED NOs: 2, 4, 6, 70, and 80. Exemplary highly stringent conditions are include hybridization at 45°C in 5X SSPE and 45% formamide, and a final wash at 65°C in 0. IX SSC. Exemplary moderately stringent condition include a final wash at 55 °C in IX SSC. It is understood in the art that conditions of equivalent stringency can be achieved through variation of temperature and buffer, or salt concentration as described Ausubel, et al. (Eds.), Protocols in Molecular Biology, John Wiley & Sons (1994), pp. 6.0.3 to 6.4.10. Modifications in hybridization conditions can be empirically determined or precisely calculated based on the length and the percentage of guanosine/cytosine (GC) base pairing ofthe probe. The hybridization conditions can be calculated as described in Sambrook, et al, (Eds.), Molecular Cloning: A aboratory Manual. Cold Spring Harbor Laboratory Press: Cold Spring Harbor, New York (1989), pp. 9.47 to 9.51. Autonomously replicating recombinant expression constructs such as plasmid and viral DNA vectors incoφorating lectomedin coding sequences are also provided. Expression constructs wherein lectomedin-encoding polynucleotides are operably linked to an endogenous or exogenous expression control DNA sequence and a transcription terminator are also provided. Expression control DNA sequences include promoters, enhancers, and operators, and are generally selected based on the expression systems in which the expression construct is to be utilized. Preferred promoter and enhancer sequences are generally selected for the ability to increase gene expression, while operator sequences are generally selected for the ability to regulate gene expression. Expression constructs ofthe invention may also include sequences encoding one or more selectable markers that permit identification of host cells bearing the construct. Expression constructs may also include sequences that facilitate, and preferably promote, homologous recombination in a host cell. Preferred constructs of the invention also include sequences necessary for replication in a host cell. Expression constructs are preferably utilized for production of an encoded lectomedin protein, but may also be utilized to amplify the construct itself. According to another aspect ofthe invention, host cells are provided, including prokaryotic and eukaryotic cells, comprising a polynucleotide ofthe invention in a manner which permits expression ofthe encoded lectomedin polypeptide. Polynucleotides ofthe invention may be introduced into the host cell as part of a circular plasmid, or as linear DNA comprising an isolated protein coding region or a viral vector. Methods for introducing DNA into the host cell well known and routinely practiced in the art include transformation, transfection, electroporation, nuclear injection, or fusion with carriers such as liposomes, micelles, ghost cells, and protoplasts. Expression systems ofthe invention include systems such as bacterial, yeast, fungal, plant, insect, invertebrate, and mammalian cells systems. Host cells of the invention are a valuable source of immunogen for development of antibodies specifically immunoreactive with lectomedin. Host cells ofthe invention are also useful in methods for large scale production of lectomedin polypeptides wherein the cells are grown in a suitable culture medium and the desired polypeptide products are isolated from the cells or from the medium in which the cells are grown by purification methods known in the art, e.g., conventional chromatographic methods including immunoaffinity chromatography, receptor affinity chromatography, hydrophobic interaction chromatography, lectin affinity chromatography, size exclusion filtration, cation or anion exchange chromatography, high pressure liquid chromatography (HPLC), reverse phase HPLC and the like. Still other methods of purification include those wherein the desired protein is expressed and purified as a fusion protein having a specific tag, label, or chelating moiety that is recognized by a specific binding partner or agent. The purified protein can be cleaved to yield the desired protein, or be left as an intact fusion protein. Cleavage ofthe fusion component may produce a form ofthe desired protein having additional amino acid residues as a result ofthe cleavage process. Knowledge of lectomedin coding DNA sequences allows for modification of cells to permit, or increase, expression of endogenous lectomedin. Cells can be modified (e.g., by homologous recombination) to provide increased lectomedin expression by replacing, in whole or in part, the naturally occurring lectomedin promoter with all or part of a heterologous promoter so that the cells express lectomedin at higher levels. The heterologous promoter is inserted in such a manner that it is operably linked to lectomedin- encoding sequences. See, for example, PCT International Publication No. WO 94/12650, PCT International Publication No. WO 92/20808, and PCT International Publication No. WO 91/09955. It is also contemplated that, in addition to heterologous promoter DNA, amplifiable marker DNA (e.g., ada, dhfr, and the multifunctional CAD gene which encodes carbamyl phosphate synthase, aspartate transcarbamylase, and dihydroorotase) and/or intron DNA may be inserted along with the heterologous promoter DNA. If linked to the lectomedin coding sequence, amplification ofthe marker DNA by standard selection methods results in co-amplification ofthe lectomedin coding sequences in the cells. The DNA sequence information provided by the present invention also makes possible the development through, e.g. homologous recombination or "knock-out" strategies [Capecchi, Science 2^: 1288-1292 (1989)], of animals that fail to express functional lectomedin or that express a variant of lectomedin. Such animals are useful as models for studying the in vivo activities of lectomedin and modulators of lectomedin. The invention also provides purified and isolated mammalian lectomedin polypeptides encoded by a polynucleotide ofthe invention. Presently preferred are lectomedin polypep.ides comprising the amino acid sequence set out in SEQ ED NO: 2, 4, 6, 70 or 80, as well as mature lectomedin polypeptides wherein signal and/or leader sequences are removed from the polypeptides of SEQ ED NOs: 2, 4, 6, 70, and 80. The invention also embraces lectomedin polypeptides encoded by a DNA selected from the group consisting of : a) the DNA sequence set out in SEQ ED NO:l, 3, 5, 69, or 79; b) a DNA molecule which hybridizes under high stringent conditions to the noncoding strand ofthe protein coding portion of (a); and c) a DNA molecule that would hybridize to the DNA of (a) but for the degeneracy ofthe genetic code. The invention further provides lectomedin polypeptides encoded by a polynucleotide selected from the group consisting of: a) the polynucleotide set out in SEQ ED NO: 1, 3, 5, 69, or 79; b) a polynucleotide encoding a polypeptide set out in SEQ ED NO: 2, 4, 6, 70, or 80; and c) a polynucleotide that hybridizes to the polynucleotide of (a) or (b) under highly or moderately stringent conditions. The invention also embraces variant (or analog) lectomedin polypeptides. In one example, insertion variants are provided wherein one or more amino acid residues supplement a lectomedin amino acid sequence. Insertions may be located at either or both termini ofthe protein, or may be positioned within internal regions ofthe lectomedin amino acid sequence. Insertional variants with additional residues at either or both termini can include for example, fusion proteins and proteins including amino acid tags or labels. In another aspect, the invention provides deletion variants wherein one or more amino acid residues in a lectomedin polypeptide are removed. Deletions can be effected at one or both termini ofthe lectomedin polypeptide, or with removal of one or more residues within the lectomedin amino acid sequence. Deletion variants, therefore, include all fragments and truncations of a lectomedin polypeptide. ln still another aspect, the invention provides substitution variants of lectomedin polypeptides. Substitution variants include those polypeptides wherein one or more amino acid residues of a lectomedin polypeptide are removed and replaced with alternative residues. In one aspect, the substitutions are conservative in nature, however, the invention embraces substitutions that are also non-conservative. Conservative substitutions for this puφose may be defined as set out in Tables A, B, or C below. The invention also provides derivatives of lectomedin polypeptides. Derivatives include lectomedin polypeptides bearing modifications other than insertion, deletion, or substitution of amino acid residues. Preferably, the modifications are covalent in nature, and include, for example, chemical bonding with polymers, lipids, non-naturally occurring amino acids, other organic, and inorganic moieties. Derivatives ofthe invention may be prepared to increase circulating half-life of a lectomedin polypeptide, or may be designed to improve targeting capacity for the polypeptide to desired cells, tissues, or organs. The invention also embraces polypeptides have at least 99%,at least 95%, at least 90%, at least 85%, at least 80%, at least 75%, at least 70%, at least 65%, at least 60%, at least 55% or at least 50% identity and/or homology to the preferred polypeptide ofthe invention. Percent amino acid sequence "identity" with respect to the preferred polypeptide ofthe invention is defined herein as the percentage of amino acid residues in the candidate sequence that are identical with the residues in the lectomedin sequence after aligning both sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity, and not considering any conservative substitutions as part ofthe sequence identity. Percent sequence "homology" with respect to the preferred polypeptide ofthe invention is defined herein as the percentage of amino acid residues in the candidate sequence that are identical with the residues in the lectomedin sequence after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity, and also considering any conservative substitutions as part ofthe sequence identity. In one aspect, percent homology is calculated as the percentage of amino acid residues in the smaller of two sequences which align with identical amino acid residue in the sequence being compared, when four gaps in a length of 100 amino acids may be introduced to maximize alignment [Dayhoff, in Altas of Protein Sequence apd Structure. Vol. 5, p. 124, National Biochemical Research Foundation, Washington, D.C. (1972), incoφorated herein by reference]. Polypeptides ofthe invention may be isolated from natural cell sources or may be chemically synthesized, but are preferably produced by recombinant procedures involving host cells ofthe invention. Use of mammalian host cells is expected to provide for such post-translational modifications (e.g., glycosylation, truncation, lipidation, and phosphorylation) as may be needed to confer optimal biological activity on recombinant expression products ofthe invention. Glycosylated and non-glycosylated forms of lectomedin polypeptides are embraced. Insertion variants include lectomedin polypeptides wherein one or more amino acid residues are added to a lectomedin acid sequence, or fragment thereof. Variant products ofthe invention also include mature lectomedin products, i.e., lectomedin products wherein leader or signal sequences are removed, with additional amino terminal residues. The additional amino terminal residues may be derived from another protein, or may include one or more residues that are not identifiable as being derived from a specific proteins. Lectomedin products with an additional methionine residue at position -1 (Mef'-lectomedin) are contemplated, as are lectomedin products with additional methionine and lysine residues at positions -2 and -1 (Met^-Lys ' ectomedin). Variants of lectomedin with multiple, additional Met, Met- Lys, Lys residues are particularly useful for enhanced recombinant protein production in bacterial host cell. The invention also embraces lectomedin variants having additional airύno acid residues which result from use of specific expression systems. For example, use of commercially available vectors that express a desired polypeptide as part of glutathione-S-transferase (GST) fusion product provides the desired polypeptide having an additional glycine residue at position -1 after cleavage ofthe GST component from the desired polypeptide. Variants which result from expression in other vector systems are also contemplated. Insertional variants also include fusion proteins wherein the amino and or carboxy termini of the lectomedin polypeptide is fused to another polypeptide. Examples of such fusion proteins are immunogenic polypeptides, proteins with long circulating half life, such as immunoglobulin constant regions, marker proteins (e.g., fluorescent) and proteins or polypeptide that facilitate purification ofthe desired ® lectomedin polypeptide, e.g. FLAG tags or polyhistidine sequences. Deletion variants include lectomedin polypeptides wherein one or more amino acid residues are deleted from the lectomedin amino acid sequence. Deletion variants ofthe invention embrace polypeptide fragments ofthe sequence set out in SEQ ED NO: 2, 4, 6, 70, or 80 wherein the fragments maintain biological or immunological properties of a lectomedin polypeptide. Fragments comprising at least 5, 10, 15, 20, 25, 30, 35, or 40 consecutive amino acids of SEQ ED NO: 2, 4, 6, 70, or 80 are comprehended by the invention. Preferred polypeptide fragments display antigenic properties unique to or specific for the lectomedin family of polypeptides. Fragments ofthe invention having the desired biological and immunological properties can be prepared by any ofthe methods well known and routinely practiced in the art. Substitution variants ofthe invention include lectomedin polypeptides, or fragments thereof, wherein one or more amino acid residues in the lectomedin amino acid sequence are deleted and replaced with another amino acid residue. Variant polypeptides include those wherein conservative substitutions have been introduced by modification of polynucleotides encoding polypeptides ofthe invention. Amino acids can be classified according to physical properties and contribution to secondary and tertiary protein structure. A conservative substitution is recognized in the art as a substitution of one amino acid for another amino acid that has similar properties. Exemplary conservative substitutions are set out in Table A (from WO 97/09433, page 10, published March 13, 1997 (PCT/GB96/02197, filed 9/6/96), immediately below. Table A Conservative Substitutions I SIDE CHAIN CHARACTERISTIC AMINO ACID Aliphatic Non-polar GAP ILV Polar - uncharged CSTM NQ Polar - charged DE KR Aromatic HFWY Other NQDE Alternatively, conservative amino acids can be grouped as described in Lehninger, [Biochemistry. Second Edition; Worth Publishers, Inc. NY:NY (1975), ρρ.71-77] as set out in Table B, immediately below. Table B Conservative Substitutions H SIDE CHAIN CHARACTERISTIC AMINO ACID Non-polar (hydrophobic) A. Aliphatic: ALIVP B. Aromatic: FW C. Sulfur-containing: M D. Borderline: G Uncharged-polar A. Hydroxyl: STY B. Amides: NQ C. Sulfhydryl: C D. Borderline: G Positively Charged (Basic): KRH Negatively Charged (Acidic): DE As still an another alternative, exemplary conservative substitutions are set out in Table C, below. Table C Conservative Substitutions HI Original Residue Exemplary Substitution Ala (A) Val, Leu, He Arg (R) Lys, Gin, Asn Asn (N) Gin, His, Lys, Arg Asp (D) Glu Cys (C) Ser Gln (Q) Asn Glu (E) Asp His (H) Asn, Gin, Lys, Arg Ile (D Leu, Val, Met, Ala, Phe, Leu (L) He, Val, Met, Ala, Phe Lys (K) Arg, Gin, Asn Met (M) Leu, Phe, He Phe (F) Leu, Val, He, Ala Pro (P) Gly Ser (S) Thr Thr (T) Ser Trp (W) Tyr Tyr OO Trp, Phe, Thr, Ser Val (V) He, Leu, Met, Phe, Ala The invention further embraces lectomedin products, or fragments thereof, covalently modified or derivatized, e.g., to include one or more water soluble polymer attachments such as polyethylene glycol, polyoxyethylene glycol, or polypropylene glycol. Particularly preferred are lectomedin products covalently modified with polyethylene glycol (PEG) subunits. Water soluble polymers may be bonded at specific positions, for example at the amino terminus of the lectomedin products, or randomly attached to one or more side chains ofthe polypeptide. Additional derivatives include lectomedin species immobilized on a solid support, pin microparticle, or chromatographic resin, as well as lectomedin polypeptides modified to include one or more non-protein labels, tags, or chelating agents. Also comprehended by the present invention are antibodies (e.g. , monoclonal and polyclonal antibodies, single chain antibodies, chimeric antibodies, bifunctional/bispecific antibodies, humanized antibodies, human antibodies, and CDR-grafted antibodies, including compounds which include CDR sequences which specifically recognize a polypeptide ofthe invention) and other binding proteins specific for lectomedin products or fragments thereof. Preferred antibodies ofthe invention are human antibodies which are produced and identified according to methods described in WO93/11236, published June 20, 1993, which is incoφorated herein by reference in its entirety. Antibody fragments, including Fab, Fab', F(ab ' ) 2 , and ¥„ are also provided by the invention. The term "specific for" indicates that the variable regions ofthe antibodies ofthe invention recognize and bind lectomedin polypeptides exclusively (i.e., able to distinguish single lectomedin polypeptides from the family of lectomedin polypeptides despite sequence identity, homology, or similarity found in the family of polypeptides), but may also interact with other proteins (for example, S. aureus protein A or other antibodies in ELISA techniques) through interactions with sequences outside the variable region ofthe antibodies, and in particular, in the constant region ofthe molecule. Screening assays to determine binding specificity of an antibody ofthe invention are well known and routinely practiced in the art. For a comprehensive discussion of such assays, see Harlow et al. (Eds), Antibodies: A Laboratory Manual: Cold Spring Harbor Laboratory; Cold Spring Harbor , NY (1988), Chapter 6. Antibodies that recognize and bind fragments ofthe lectomedin polypeptides ofthe invention are also contemplated, provided that the antibodies are first and foremost specific for, as defined above, lectomedin polypeptides. As with antibodies that are specific for full length lectomedin polypeptides, antibodies ofthe invention that recognize lectomedin fragments are those which can distinguish single and distinct lectomedin polypeptides from the family of lectomedin polypeptides despite inherent sequence identity, homology, or similarity found in the family of proteins. Antibodies ofthe invention can be produced using any method well known and routinely practiced in the art. Non-human antibodies may be humanized by any methods known in the art. In one method, the non-human complementarity determining regions (CDRs) are inserted into a human antibody or consensus antibody framework'sequence. Further changes can then be introduced into the antibody framework to modulate affinity or immunogenicity. Antibodies ofthe invention are useful for, for example, therapeutic puφoses (by modulating activity of lectomedin), diagnostic puφoses to detect or quantitate lectomedin, as well as purification of lectomedin. Antibodies are particularly useful for detecting and/or quantitating lectomedin expression in cells, tissues, organs and lysates and extracts thereof, as well as fluids, including serum, plasma, cerebrospinal fluind, urine, sputum, peritoneal fluid, pleural fluid, or pulmonary lavage. Kits comprising an antibody ofthe invention for any ofthe puφoses described herein are also comprehended. In general, a kit ofthe invention, with or without a container, also includes a control antigen for which the antibody is immunospecific. Specific binding proteins can be identified or developed using isolated or recombinant lectomedin products, lectomedin variants, or cells expressing such products. Binding proteins are useful for purifying lectomedin products and detection or quantification of lectomedin products in fluid and tissue samples using known immunological procedures. Binding proteins are also manifestly useful in modulating (i.e., blocking, inhibiting or stimulating) biological activities of lectomedin, especially those activities involved in signal transduction. Presently preferred binding proteins include galectin-3 (Mac-2); fibrinogen; immunoglobulin mu chain constant region; KIAA0445; hepatitis Delta antigen-interacting protein dipA; kinesin-related protein, KIF3C; G0/G1 regulatory switch protein G0S3 (FOSB); neuron-specific amyloid protein showing homology to AMY; RanBpm; AD A3 -like protein that is part ofthe PCAF histone acetylase complex; and human genomic clone 18_A_13 ® (GenBank Accession No: AC007198), as described below. The DNA and amino acid sequence information provided by the present invention also makes possible the systematic analysis ofthe structure and function of lectomedins. DNA and amino acid sequence information for lectomedin also permits identification of binding partner compounds with which a lectomedin polypeptide or polynucleotide will interact. Agents that modulate (i.e., increase, decrease, or block) lectomedin activity or expression may be identified by incubating a putative modulator with a lectomedin polypeptide or polynucleotide and determining the effect ofthe putative modulator on lectomedin activity or expression. The selectivity of a compound that modulates the activity ofthe lectomedin can be evaluated by comparing its binding activity to one particular lectomedin to its activity to other lectomedin polypeptides. Cell based methods, such as di-hybrid assays to identify DNAs encoding binding compounds and split hybrid assays to identify inhibitors of lectomedin polypeptide interaction with a known binding polypeptide, as well as in vitro methods, including assays wherein a lectomedin polypeptide, lectomedin polynucleotide, or a binding partner are immobilized, and solution assays are contemplated by the invention. Selective modulators may include, for example, antibodies and other proteins or peptides which specifically bind to a lectomedin polypeptide or a lectomedin-encoding nucleic acid, oligonucleotides which specifically bind to a lectomedin polypeptide or a lectomedin gene sequence, and other non-peptide compounds (e.g., isolated or synthetic organic and inorganic molecules) which specifically react with a lectomedin polypeptide or its underlying nucleic acid. Mutant lectomedin polypeptides which affect the enzymatic activity or cellular localization of the wild-type lectomedin polypeptides are also contemplated by the invention. Presently preferred targets for the development of selective modulators include, for example: (1) regions ofthe lectomedin polypeptide which contact other proteins, (2) regions that localize the lectomedin polypeptide within a cell, (3) regions ofthe lectomedin polypeptide which bind substrate, (4) allosteric regulatory binding site(s) of the lectomedin polypeptide, (5) site(s) ofthe lectomedin polypeptide wherein covalent modification regulates biological activity and (6) regions ofthe lectomedin polypeptide which are involved in multimerization of lectomedin subunits. Still other selective modulators include those that recognize specific lectomedin encoding and regulatory polynucleotide sequences. Modulators of lectomedin activity may be therapeutically useful in treatment of a wide range of diseases and physiological conditions in which lectomedin activity is known or suspected to be involved. The invention also provides methods to modulate binding between lectomedin and a binding partner thereof, said method comprising the step of contacting lectomedin or the binding partner with a modulator of binding between lectomedin and the binding partner. The methods may result in increased binding when the modulator is an enhancer of binding, or may result in decreased binding when the modulator is an inhibitor of binding. The invention further provides methods for identifying a modulator cf lectomedin binding to a binding partner comprising the steps of: a) measuring binding between lectomedin and the binding partner in the presence and absence of a test compound; and b) identifying the test compound as a modulator of lectomedin binding to the binding partner binding when a different level of lectomedin binding to the binding partner is detected in the presence ofthe test compound compared to lectomedin binding the binding partner in the absence ofthe test compound. In a preferred method, the binding partner is selected from the group consisting of galectin- 3 (Mac-2); fibrinogen; immunoglobulin mu chain constant region; KIAA0445; hepatitis Delta antigen-interacting protein dip A; kinesin-related protein, KEF3C; G0/G1 regulatory switch protein G0S3 (FOSB); neuron-specific amyloid protein homologous to AMY; RANBPM; AD A3 -like protein that is part ofthe PCAF histone acetylase ® complex; and human genomic clone 18_A_13 (GenBank Accession No: AC007198) The invention also provides methods for modulating lectomedin binding to a binding partner comprising the step of contacting lectomedin or the binding partner with a modulator of lectomedin binding to the binding partner. Preferred methods ofthe invention include those wherein the modulator is an inhibitor and those wherein the modulator is an enhancer. Preferably, the binding partner is selected from the group consisting of galectin-3 (Mac-2); fibrinogen; immunoglobulin mu chain constant region; KIAA0445; hepatitis Delta antigen-interacting protein dipA; kinesin-related protein, KEF3C; G0/G1 regulatory switch protein G0S3 (FOSB); neuron-specific amyloid protein homologous to AMY; RANBPM; ADA3-like protein that is part ofthe PCAF histone acetylase complex; and human genomic clone 18_A_13 (GenBank® Accession No: AC007198) The invention further provides methods to ameliorate a disease state associated with lectomedin binding to a binding partner comprising the step of administering to an individual in need thereof an effective amount of a modulator of lectomedin binding to the binding partner. In preferred methods, the binding partner is selected from the group consisting of galectin-3 (Mac-2); fibrinogen; immunoglobulin mu chain constant region; KIAA0445; hepatitis Delta antigen-interacting protein dip A; kinesin-related protein, KEF3C; G0/G1 regulatory switch protein G0S3 (FOSB); neuron-specific amyloid protein homologous to AMY; RANBPM; AD A3 -like protein that is part ofthe PCAF histone acetylase complex; and human genomic clone ® 18_A_13 (GenBank Accession No: AC007198). In one aspect, methods ofthe invention include those wherein the modulator inhibits binding between lectomedin and the binding partner. In another aspect, the method utilizes a modulator that enhances binding between lectomedin and the binding partner. In a most preferred method, the binding partner is galectin-3 and the disease state is selected from the group consisting of atherosclerosis, restenosis or vascular disease. The invention further provides methods to ameliorate a disease state wherein lectomedin binding to a binding partner participates, said method comprising the step of administering to an individual in need thereof a modulator of lectomedin binding to the binding partner. In one aspect, methods ofthe invention include administering to an individual in need thereof an inhibitor of lectomedin binding to a binding partner. In another aspect, the methods include administering to an individual in need thereof an enhancer of lectomedin binding to a binding partner. In a preferred method ofthe invention, the disease state is atherosclerosis, restenosis, vascular disease, peripheral neuropathy, cancer (specifically ofthe thyroid, breast, ski, colon, head, neck, nervous system, and prostate), nerve regeneration, pathologies ofthe renal cystic epithelia (i.e., multicystic dysplasia and polycystronic kidney disease) and uterine implantation. Lecto edin polypeptides of the invention are amenable to numerous cell based high throughput screening (HTS) assays known in the art, including melanophore assays to investigate receptor-ligand interaction, yeast based assay systems, and mammalian cell expression systems. For a review, see Jayawickreme and Kost, Curr. Opin. Biotechnol. 5:629-634 (1997). Automated and miniaturized HTS assays are also comprehended as described, for example, in Houston and Banks, Curr. Opin. Biotechnol. 5:734-740 (1997) There are a number of different libraries used for the identification of small molecule modulators, including, (1) chemical libraries, (2) natural product libraries, and (3) combinatorial libraries comprised of random or designed peptides, oligonucleotides or organic molecules. Chemical libraries consist of structural analogs of known compounds or compounds that are identified as "hits" or "leads" via natural product screening. Natural product libraries are collections of microorganisms, animals, plants, or marine organisms which are used to create mixtures for screening by: (1) fermentation and extraction of broths from soil, plant or marine microorganisms or (2) extraction of plants or marine organisms. Natural product libraries include polyketides, non-ribosomal peptides, and variants (non-naturally occurring) variants thereof. For a review, see Science 252:63-68 (1998). Combinatorial libraries are composed of large numbers of peptides, oligonucleotides or organic compounds as a mixture. They are relatively easy to prepare by traditional automated synthesis methods, PCR, cloning or proprietary synthetic methods. Of particular interest are peptide and oligonucleotide combinatorial libraries. Still other libraries of interest include peptide, protein, peptidomi etic, multiparallel synthetic collection, recombinatorial, and polypeptide libraries. For a review of combinatorial chemistry and libraries created therefrom, see Myers, Curr. Opin. Biotechnol. 5:701-707 (1997). Identification of modulators through use ofthe various libraries described herein permits modification ofthe candidate "hit" (or "lead") to optimize the capacity ofthe "hit" to modulate activity. The scientific value of the information contributed through the disclosures of DNA and amino acid sequences ofthe present invention is manifest. As one series of examples, knowledge ofthe sequence of a cDNA for lectomedin makes possible through use of Southern hybridization or polymerase chain reaction (PCR) the identification of genomic DNA sequences encoding lectomedin and lectomedin expression control regulatory sequences such as promoters, operators, enhancers, repressors, and the like. DNADNA hybridization procedures carried out with DNA sequences ofthe invention under moderately to highly stringent conditions are likewise expected to allow the isolation of DNAs encoding allelic variants of lectomedin; allelic variants are known in the art to include structurally related proteins sharing one or more ofthe biochemical and/or immunological properties specific to lectomedin. Similarly, non-human species genes encoding proteins homologous to human lectomedin can also be identified by Southern and/or PCR analysis; species homologs ofthe invention are particularly useful in animal models for the study of lectomedin- related disorders. As an alternative, complementation studies can be useful for identifying other human lectomedin products as well as non-human proteins, and DNAs encoding the proteins, sharing one or more biological properties of lectomedin. Polynucleotides ofthe invention are also useful in hybridization assays to detect the capacity of cells to express lectomedin. Polynucleotides ofthe invention may also be the basis for diagnostic methods useful for identifying a genetic alteration(s) in a lectomedin locus that underlies a disease state or states. Also made available by the invention are antisense polynucleotides which recognize and hybridize to polynucleotides encoding lectomedin. Full length and fragment antisense polynucleotides are provided. The worker of ordinary skill will appreciate that fragment antisense molecules ofthe invention include (i) those which specifically recognize and hybridize to lectomedin RNA (as determined by sequence comparison of DNA encoding lectomedin to DNA encoding other known molecules) as well as (ii) those which recognize and hybridize to RNA encoding variants ofthe lectomedin family of proteins. Antisense polynucleotides that hybridize to RNA encoding other members ofthe lectomedin family of proteins are also identifiable through sequence comparison to identify characteristic, or signature, sequences for the family of molecules. Antisense polynucleotides are particularly relevant to regulating expression of lectomedin by those cells expressing lectomedin mRNA. Antisense nucleic acids (preferably 10 to 20 base pair oligonucleotides) capable of specifically binding to lectomedin expression control sequences or lectomedin RNA are introduced into cells (e.g. , by a viral vector or colloidal dispersion system such as a liposome). The antisense nucleic acid binds to the lectomedin target nucleotide sequence in the cell and prevents transcription or translation of the target sequence. Phosphorothioate and methylphosphonate antisense oligonucleotides are specifically contemplated for therapeutic use by the invention. The antisense oligonucleotides may be further modified by poly-L- lysine, transferrin polylysine, or cholesterol moieties at their 5' ends. The invention further contemplates methods to modulate lectomedin expression through use of ribozymes. For a review, see Gibson and Shillitoe, Mol Biotech. 7:125-137 (1997). Ribozyme technology can be utilized to inhibit translation of lectomedin mRNA in a sequence specific manner through (i) the hybridization of a complementary RNA to a target mRNA and (ii) cleavage ofthe hybridized mRNA through nuclease activity inherent to the complementary strand. Ribozymes can be identified by empirical methods but more preferably are specifically designed based on accessible sites on the target mRNA (Bramlage, et al, Trends in Biotech 76:434-438 (1998). Delivery of ribozymes to target cells can be accomplished using either exogenous or endogenous delivery techniques well known and routinely practiced in the art. Exogenous delivery methods can include use of targeting liposomes or direct local injection. Endogenous methods include use of viral vectors and non-viral plasmids. Ribozymes can specifically modulate expression of lectomedin when designed to be complementary to regions unique to a polynucleotide encoding lectomedin. "Specifically modulate" therefore is intended to mean that ribozymes of the invention recognizes only a polynucleotide encoding lectomedin. Similarly, ribozymes can be designed to modulate expression of all or some ofthe lectomedin family of proteins. Ribozymes of this type are designed to recognize polynucleotide sequences conserved in all or some ofthe polynucleotides which encode the family of proteins. The invention further embraces methods to modulate transcription of lectomedin through use of oligonucleotide-directed triplet helix formation. For a review, see Lavrovsky, et al, Biochem. Mol. Med. 62: 11-22 (1997). Triplet helix formation is accomplished using sequence specific oligonucleotides which hybridize to double stranded DNA in the major groove as defined in the Watson-Crick model. Hybridization of a sequence specific oligonucleotide can thereafter modulate activity of DNA-binding proteins, including, for example, transcription factors and polymerases. Preferred target sequences for hybridization include promoter and enhancer regions to permit transcriptional regulation of lectomedin expression. Oligonucleotides which are capable of triplet helix formation are also useful for site-specific covalent modification of target DNA sequences. Oligonucleotides useful for covalent modification are coupled to various DNA damaging agents as described in Lavrovsky, et al [supra]. Mutations in a lectomedin gene that results in loss of normal function of the lectomedin gene product may underlie lectomedin-related human disease states. The invention comprehends gene therapy to restore lectomedin activity would thus be indicated in treating those disease states (for example, various forms of cancer described herein). Delivery of a functional lectomedin gene to appropriate cells is effected ex vivo, in situ, or in vivo by use of vectors, and more particularly viral vectors (e.g. , adenovirus, adeno-associated virus, or a retrovirus), or ex vivo by use of physical DNA transfer methods (e.g. , liposomes or chemical treatments). See, for example, Anderson, Nature, supplement to vol. 392, no. 6679, pp.25 (1998). For additional reviews of gene therapy technology see Friedmann, Science, 244: 1275-1281 (1989); Verma, Scientific American: 68-84 (1990); and Miller, Nature, 357: 455-460 (1992). Alternatively, it is contemplated that in other human disease states, preventing the expression of or inhibiting the activity of lectomedin will be useful in treating the disease states. It is contemplated that antisense therapy or gene therapy could be applied to negatively regulate the expression of lectomedin. The invention further embraces pharmaceutical compositions comprising a lectomedin polypeptide ofthe invention, generally in combination with a pharmaceutically acceptable carrier. The pharmaceutical compositions optionally may include pharmaceutically acceptable (/.e. p sterile and non-toxic) liquid, semisolid, or solid diluents that serve as pharmaceutical vehicles, excipients, or media. Any diluent known in the art may be used. Exemplary diluents include, but are not limited to, polyoxyethylene sorbitan monolaurate, magnesium stearate, methyl- and propylhydroxybenzoate, talc, alginates, starches, lactose, sucrose, dextrose, sorbitol, mannitol, gum acacia, calcium phosphate, mineral oil, cocoa butter, and oil of theobroma. The pharmaceutical compositions can be packaged in forms convenient for delivery. The compositions can be enclosed within a capsule, sachet, cachet, gelatin, paper, or other container. These delivery forms are preferred when compatible with entry ofthe immunogenic composition into the recipient organism and, particularly, when the immunogenic composition is being delivered in unit dose form. The dosage units can be packaged, e.g., in tablets, capsules, suppositories or cachets. The pharmaceutical compositions may be introduced into the subject to be treated by any conventional method including, e.g., by intravenous, intradermal, intramuscular, intramammary, intraperitoneal, intrathecal, intraocular, retrobulbar, intrapulmonary (e.g., aerosolized drug solutions) or subcutaneous injection (including depot administration for long term release) ; by oral, sublingual, nasal, anal, vaginal, or transdermal delivery; or by surgical implantation, e.g., embedded under the splenic capsule, brain, or in the cornea. The treatment may consist of a single dose or a plurality of doses over a period of time. When given parenterally, lectomedin product compositions are generally injected in doses ranging from 1 μg/kg to 100 mg/kg per day, preferably at doses ranging from 0.1 mg/kg to 50 mg/kg per day, and more preferably at doses ranging from 1 to 20 mg/kg/day. The lectomedin product composition may be administered by an initial bolus followed by a continuous infusion to maintain therapeutic circulating levels of drug product. Those of ordinary skill in the art will readily optimize effective dosages and administration regimens as determined by good medical practice and the clinical condition of the individual patient. The frequency of dosing will depend on the pharmacokinetic parameters of the agents and the route of administration. The optimal phaπnaceutical formulation will be determined by one skilled in the art depending upon the route of administration and desired dosage. See for example, Remington's Pharmaceutical Sciences, 18th Ed. (1990, Mack Publishing Co. , Easton, PA 18042) pages 1435-1712, the disclosure of which is hereby incorporated by reference. Such formulations may influence the physical state, stability, rate of in vivo release, and rate of in vivo clearance of the admimstered agents. Depending on the route of administration, a suitable dose may be calculated according to body weight, body surface area or organ size. Further refinement of the calculations necessary to determine the appropriate dosage for treatment involving each of the above mentioned formulations is routinely made by those of ordinary skill in the art without undue experimentation, especially in light of the dosage information and assays disclosed herein, as well as the pharmacokinetic data observed in the human clinical trials discussed above. Appropriate dosages may be ascertained through use of established assays for determining blood levels dosages in conjunction with appropriate dose-response data. The final dosage regimen will be determined by the attending physician, considering various factors which modify the action of drugs, e.g. the drug's specific activity, the severity of the damage and the responsiveness of the patient, the age, condition, body weight, sex and diet of the patient, the severity of any infection, time of administration and other clinical factors. As studies are conducted, further information will emerge regarding the appropriate dosage levels and duration of treatment for various diseases and conditions. It will be appreciated that the pharmaceutical compositions and treatment methods ofthe invention may be useful in the fields of human medicine and veterinary medicine. Thus, the subject to be treated may be a mammal, preferably human, or other animals. For veterinary puφoses, subjects include, for example, farm animals including cows, sheep, pigs, horses, and goats, companion animals such as dogs and cats; exotic and/or zoo animals; laboratory animals including mice, rats, rabbits, guinea pigs, and hamsters; and poultry such as chickens, turkeys, ducks and geese. The present invention is illustrated by the following examples. Example 1 describes identification and characterization of cDNA encoding lectomedin polypeptides. Example 2 relates to expression of recombinant lectomedin polypeptides. Example 3 described characterization of recombinant lectomedin polypeptides. Ligand affinity chromatography with immobilized lectomedin polypeptides is described in Example 4. Example 5 describes Northern and dot blot analysis of lectomedin expression. Example 5 provides an assessment of tissue distribution of lectomedins in mammalian cell types, while Example 6 describes results from in situ hybridization. The chromosome localization of lectomedins are disclosed in Example 7. Example 8 provides production of polyclonal and monoclonal antibodies specific for lectomedins. Example 9 addresses in situ lectomedin expression using immunocytochemistry. Example 10 relates to localization of lectomedin- 1 and galectin-3 in atherosclerotic tissues. Example 11 describes localization of lectomedin- 1 and galectin-3 in ApoE knockout mice. Example 12 relates to glycosidase treatment of lectomedin- lα. Example 13 describes glycosidase treatment of lectomedin- lα. Example 14 further confirms lectomedin- 1 binding to galectin-3. Example 15 relates to effects of glycosidases on lectomdin-lα binding to galectin. Example 16 describes lectomedin-2 expression in HEK293T cells. Example 17 relates to two hybrid screening to identify lectomedin binding partners. Example 1 Isolation and Characterization of Human Lectomedin Identification of Lectomedin-l« In an attempt to identify genes encoding novel seven transmembrane receptor proteins related to CD97, a TBLASTN search ofthe National Center for Biotechnology Information (NCBI, Bethesda, MD) Expressed Sequence Tag (EST) database was carried out with an amino acid query sequence for full length CD97 (SEQ ED NO: 12). This database contains DNA sequences representing one or both ends of cDNAs collected from a variety of tissue sources. The TBLASTN program was used to determine homology between the protein sequence of CD97 and the six different amino acid sequences encoded by each EST. In the search, ESTs are translated in six reading frames and the amino acid sequences generated are compared to the query CD97 amino acid sequence. Sequences identified as homologous at the amino acid level were examined and any ESTs positively identified as corresponding to a known protein were discarded. Among the CD97-related sequences identified as conesponding to known proteins were ESTs representing CD97, human EMR1, and murine F4/80. In addition, several ESTs showed statistically significant values for relatedness in the transmembrane region of CD97, but they were not CD97, EMR1 , or F4/80. One of ® ® tthhee iiddeennttiififieedd EESSTTss,, ddeessiiggnnaatteedd GGeennBBaannkk AAcccceessssiioonn NNoo:: TT4477990022 ((SSEEQQ EEDD NNOO:: 1123), was chosen to attempt identificationn o cf a full length cDNA. The basis for choosing ® TT4477990022 wwaass ddiisclosure in GenBank that the EST was derived from a human fetal spleen library. ® A library probe was first generated by PCR based on the GenBank sequence of T47902. Primers used to amplify a T47902 sequence are set out in SEQ ED NOs: H and 15 below. 5' TGGAGTTTCAGCTGCTATTG SEQ EDNO: 14 5' TGCCCATCCACAATAGTCTC SEQ EDNO: 15 Mixed human adult spleen cDNA was prepared by standard methods and ligated into vector pcDNAl.amp (Invitrogen) [Van der Vieren, M. et al. Immunity 3:683-690 (1995)]. The resulting plasmid mixture was transformed into E. coli and the bacteria were plated onto LB bacterial plates containing carbenicillin (100 μg/ml). Surviving colonies were collected by scraping and plasmid DNA was prepared by the alkaline lysis method. The cDNA mixture was used as a template for PCR in a reaction mixture including 350 ng cDNA, 100 ng each primer (SEQ ED NO. 14 and NO. 15), 200 μM each deoxynucleotide triphosphate (adenosine, thymidine, cytidine and guanosine), 10 mM Tris-HCl, pH 8.3 (at 25°C), 50 mM KCl, 1.5 mM MgCl 2 , and 5 units Taq polymerase (Perkin Elmer Coφ., Foster City, CA). PCR was carried out with an initial denaturation step of seven minutes at 95 °C followed by 30 cycles of denaturation for one minute at 95 °C, hybridization for one minute at 55 °C, and extension two minutes at 74 °C. After PCR, 10 μl ofthe reaction was separated on a 1.5% agarose gel and an amplification product of 306 bp was detected following ethidium bromide staining. The 306 bp product was eluted from the gel using ® GeneClean (BIO 101 Inc., Vista CA) according to the manufacturer's suggested ® ® protocol and ligated into vector pCR2.1 (TA Cloning kit, Invitrogen, Carlsbad, CA). The resulting plasmid preparation was transformed into E. coli and the cells plated as described above. Several colonies were selected for DNA minipreps and the cDNA inserts were sequenced. ® ® The 306 bp insert was excised from the pCR2.1 TA Cloning vector by digestion with EcoRI. Following digestion, DNA fragments were fractionated on an agarose gel. A band of approximately 306 bp was eluted from the gel and labeled by random priming according to standard procedures. The labeled probe was used to screen the human spleen adult cDNA pcDNAl library (described above) immobilized on nylon membranes following colony lifts from cells spread on LB/carbenicillin plates. Two cDNA clones, designated 3.3 and 15.3.1, were obtained and purified. Clone 3.3 included an insert of approximately 4200 bp and clone 15.3.1 contained an insert of approximately 2750 bp. Both clones were sequenced by standard automated methods. The nucleotide sequence for clone 3.3 is set out in SΕQ ΕD NO: 9 and the predicted amino acid encoded is set out in SΕQ ΕD NO: 10. The nucleotide sequence for clone 15.3.1 is set out in SΕQ ΕD NO: 16. It was initially presumed that the two clones represented a single cDNA sequence and, relying predominantly on the larger 3.3 insert, a contiguous cDNA was predicted. Neither insert, however, encoded a complete open reading frame, as evidenced by the fact that an in-frame ATG translation start site preceded by a Kozak translation initiator sequence and an in-frame stop codon were not found. In an attempt to isolate the 5' end ofthe complete cDNA, RACE PCR was carried out using a human spleen cDNA library (Marathon™ cDNA, Clontech, La Jolla. CA). Nested primers (SEQ ED NOs: 17 and 18) utilized in the PCR were designed based on the library vector and clone 3.3 sequences. 5' GTGATCCAGCTACAGTTGTGCTCAT SEQ EDNO: 17 5' CTAATGCTTCACAGAATCTCTCTGGC SEQ IDNO: 18 Five microliters of cDNA prepared from human spleen RNA or peripheral blood leukocyte RNA was added to separate reactions with 100 ng downstream nested gene specific primer, adapter primer API (Marathon™ cDNA kit; Clontech Inc., Palo Alto CA), 200 μM each deoxynucleotide triphosphate (adenosine, thymidine, cytidine, and guanosine), 10 mM Tris-HCl, pH 8.3 (at 25 °C), 50 mM KCl, 1.5 mM MgCl 2 , 5 units Taq polymerase. PCR was carried out with an initial denaturation step for two minutes at 94°C, followed by (i) five cycles of 0.05 minutes at 94°C and seven minutes at 74°C, (ii) five cycles of 0.05 minutes at 94°C and seven minutes at 72°C, and (iii) 25 cycles of 0.05 minutes at 94°C and seven minutes at 70°C. Following amplification, the reaction mixture was diluted 1:50, and 5 μl was used in a second amplification reaction including 100 ng upstream internal gene specific primer and adapter primer AP2 (Marathon™ cDNA kit, Clontech) with the same cycling conditions as in the first amplification. Amplification products from the second reaction were separated on a 0.9% agarose gel and a band of approximately 2 kb in the ® gel was eluted for subcloning into vector pCR2.1 as above. The isolated fragment was designated RACE3.3. The nucleotide and predicted amino acid sequences for the fragment are set out in SEQ ED NOs: 7 and 8, respectively. When the RACE3.3 sequence was correlated with the sequence for the spleen clone 3.3 to account for overlap, an open reading frame (SEQ ED NO: 33) was deduced encoding a polypeptide of 1114 amino acids (SEQ ED NO: 34) and a predicted molecular weight of approximately 125 kD. Even thought the EST used to screen the spleen library was selected based on sequence similarity to CD97, the polypeptide encoded by the overlapping clones was presumed to represent a unique family of human proteins, related to, but distinct from, any previously identified in ® GenBank . The putative extracellular domain in the predicted arnino acid sequence did not include EGF domains characteristic ofthe CD97-like protein family and the amino acid sequence ofthe transmembrane domain in the predicted protein was only about 45-60% identical to the transmembrane domains of CD97. In addition, the predicted amino acid sequence deduced from the combined RACE3.3 and clone 3.3 open reading frame included potential lectin-binding, olfactomedin-like, and mucin-like extracellular domains not found in CD97. Based on the presence ofthe extracellular lectin binding-like and olfactomedin-like domains, the polypeptide encoded by the RACE3.3 and clone 3.3 sequences was designated lectomedin- l α. ® A later BLAST search ofthe GenBank database using the lectomedin- lα sequence indicated that lectomedin- lα was related to the rat receptor for α-latrotoxin designated latrophilin [Lenianova, et al, J. Biol. Chem. 272:21504- 21508 (1997)], and the calcium-independent receptor of α-latrotoxin (CE L) [Krasnoperov, supra]. Both human lectomedin- lα and rat latrophilin have extracellular lectin binding-like and olfactomedin-like domains, in addition to a seven transmembrane region and a cytoplasmic domain also found in CD97. Lectomedin- 1 α also includes a sequence at amino acid residues 809 to 814 (in SEQ ED NO: 2) which is similar to a proposed cleavage site conserved in both CD97 and latrophilin. It is possible that these three proteins are processed by an endoprotease (or related proteases) with similar primary sequence specificity. In view of these similarities, lectomedin- lα may be related to a human homolog ofthe rat latrophilin and may participate in stimulation/secretion coupling in presynaptic termini and/or secretory granule release. Expression of lectomedin- 1 in cell and tissue types outside the central nervous system (discussed below), however, indicates that lectomedin is functionally distinct from latrophilin. The overall amino acid sequence of lectomedin- lα was found to be approximately 80% identical to that of latrophilin, but the amino acid sequence ofthe latrophilin cytoplasmic domain was unrelated to the predicted cytoplasmic domain of lectomedin- lα. In addition, the location ofthe initiating methionine in latrophilin differed from that in the predicted open reading frame of lectomedin- lα. After further analysis ofthe lectomedin- lα polynucleotide sequence, however, a methionine codon in a different reading frame was identified upstream from the originally predicted open reading frame. The location ofthe upstream methionine codon (with respect to the transmembrane region) more closely corresponded to the position ofthe latrophilin initiating methionine and the first few amino acids in reading frame with the upstream methionine codon also corresponded to the sequence in latrophilin. In view ofthe potential similarity to latrophilin, the polynucleotide sequence encoding the 1114 amino acid lectomedin- lα open reading frame was again compared to the raw data obtained during automated sequencing ofthe RACE3.3 cDNA. Further inspection showed that a guanosine nucleotide at position 454 had been entered in SEQ ED NO: 33, but was not present in the raw sequence data. The corrected nucleotide sequence for RACE3.3 (i.e., having the extraneous guanosine nucleotide deleted) together with the sequence of clone 3.3 (SEQ ED NO: 9) showed an open reading frame encoding 1177 amino acids. The corrected open reading frame began with the newly identified initiating methionine and encoded the previously identified lectin binding-like, olfactomedin-like, mucin-like, transmembrane and cytoplasmic domains of lectomedin-lα (SEQ ED NO: 1). Based on sequence homology with known proteins, domains in various regions ofthe lectomedin-lα protein were identified. An extracellular region of approximately 831 amino acids showed homology to a previously reported D-galactoside binding lectin binding-like domain [Ozeki, et al, Biochemistry 30:2391- 2394 (1991)] (lectomedin-lα amino acids 36 to 131 of SEQ ED NO: 2) and an olfactomedin-like domain [Yokoe and Anholt, Proc. Natl. Acad Sci. (USA) 90:4655- 4659 (1993)] (lectomedin-lα amino acids 135 to 327 of SEQ ED NO: 2). Three extracellular and three intracellular domains were separated by seven transmembrane domains (amino acids 832 to 1075 of SEQ ED NO: 2) characteristic of G-protein coupled receptors (GPCR) [Kobilka, et al, Science 235:650-656 (1987)]. A cytoplasmic region of 102 amino acids was adjacent the transmembrane region. Based on the observation that lectomedin-lα contained a region from amino acids 354 to 563 (SEQ ED NO: 2) with many serine and threonine residues (which may be O- glycosylated), as well as many proline residues (which break up alpha helices resulting in an extended structure with many beta turns), a mucin-like domain was identified. Identification of Additional ^ctomedin-l Species The sequence for lectomedin-lα was based on the sequences determined for clone 3.3 and the fragment RACE3.3. A second lectomedin cDNA could also be deduced based on the sequence ofthe second spleen clone 15.3.1. In comparing the sequences for clones 3.3 and 15.3.1, it was first noted that the clones were substantially identical throughout both 5' regions, except that an adenosine required at position 1620 of clone 3.3 (SEQ ID NO: 7) was apparently not present in clone 15.3.1. As a result, the reading frame of clone 15.3.1 was shifted in comparison to the reading frame of clone 3.3, and thus, clone 15.3.1 did not encode a protein having the characteristic seven transmembrane domain found in lectomedin-lα. When the variant adenosine was inserted into the sequence for clone 15.3.1 , the predicted protein sequence was consistent with the lectomedin- lα amino acid sequence up to the first amino acid residue in the cytoplasmic domain. This sequence suggested an alternative splice site in the cytoplasmic region of clone 15.3.1 that produced a shorter cDNA comprising a cytoplasmic domain of approximately forty-eight amino acids (as compared to 107 amino acids in the cytoplasmic domain ofthe lectomedin-lα cDNA derived solely from clone 3.3 sequences). The lectomedin-lα cDNA deduced from clone 3.3 also terminated at an alternative poly(A + ) site 210 nucleotides upstream from the coπesponding poly(A + ) site identified in clone 15.3.1. The differences suggested that clone 15.3.1 represents a second member ofthe lectomedin family, which was designated lectomedin- lβ. A deduced polynucleotide sequence for lectomedin- lβ was therefore generated using the overlapping sequence from clone 3.3 (which extended the 5' region of clone 15.3.1) and the RACE3.3 sequence (to provide an appropriate 5 ' end); the complete predicted cDNA and deduced amino acid sequences for lectomedin- lβ are set out in SEQ ED NOs: 3 and 4, respectively. Characterization ofthe predicted amino acid sequence for lectomedin- lβ provides various domains similar (in both sequence and position) to those identified for lectomedin-lα. An extracellular region of approximately 831 amino acids is predicted, including a D-galactoside-binding lectin-like domain (amino acids 36 to 131 of SEQ ED NO: 4), an olfactomedin-like domain (amino acids 135 to 327 of SEQ ED NO: 4), and a mucin-like domain (amino acids 354 to 563 of SEQ ED NO: 4). A seven transmembrane domain (amino acids 832 to 1075 of SEQ ED NO: 4) was located adjacent the extracellular domain, and a cytoplasmic region of 48 amino acids (residues 1076 to 1123 of SEQ ED NO: 4) was located adjacent the transmembrane region. The originally identified EST designated T47902 (SEQ ED NO: 13) was ® described in GenBank to represent the 5' end of a cDNA clone designated 71509 ® (SEQ ED NO: 21), and when GenBank was further searched for a DNA sequence representing the 3 ' end of clone 71509, a second EST designated T47903 (SEQ ED NO: 30) was identified. Clone 71509 (SEQ ED NO: 21) was purchased, sequenced, and compared to the coπesponding regions in lectomedin-lα and lectomedin-lβ. The sequence of clone 71509 was identical to portions ofthe lectomedin-lα and lβ sequences, but, like the alternative splicing apparent from comparing lectomedin-lα and lectomedin-lβ, yet another alternative splicing event was found based on the sequence of clone 71509. Specifically, the sequence of clone 71509 was found to lack a 106 bp sequence found in clone 3.3. Clone 15.3.1 also lacked the same 106 bp and an additional 97 bp of 5' upstream DNA. Clone 15.3.1 therefore lacked 203 bp of sequence found in the lectomedin-lα clone. The 106 bp deletion resulted in a frame shift in the region encoding the cytoplasmic domain, providing a third lectomedin protein. This third alternative lectomedin polynucleotide and predicted amino acid sequence (SEQ ED NO: 5 and 6, respectively) was designated lectomedin- lγ. As with the other lectomedin polypeptides, lectomedin- lγ is predicted to include (i) an extracellular region of approximately 831 amino acids with a D-galactoside binding lectin-like domain (amino acids 36 to 131 of SEQ ED NO: 6), an olfactomedin-like domain (amino acids 135 to 327 of SEQ ED NO: 6) and a mucin-like domain (amino acids 354 to 563 of SEQ ED NO: 6), (ii) a seven transmembrane region (amino acids 832 to 1075 of SEQ ED NO: 6), and (iii) a cytoplasmic region of 328 amino acids (amino acids 1076 to 1403 of SEQ ED NO: 6). The sequences at which the three clones diverged showed hallmarks of the canonical 3' exon sequence with the presence of an AG dinucleotide. However, these regions differed from the accepted intron junction sequences which have been found to include highly conserved GT dinucleotides [GENES IV. B. Lewin, Cell Press, Cambridge MA (1992), p. 597]. The identification of these sequences indicated that the clones were derived from alternatively spliced RNAs rather than from incomplete RNA splicing wherein the canonical exon/intron junction sequence (AG/GT) would be expected. Identification of Lectomedin-2 Lectomedin l α and rat latrophilin (SEQ ED NO: 19) were used as query sequences in a subsequent BLAST search in an attempt to identify any additional ESTs with sequence homology. Two human ESTs designated AA683020 (SEQ ED NO: 22) and M79057 (SEQ ED NO: 23) were identified as being closely related to both lectomedin-lα and rat latrophilin. The sequence for EST AA683020 corresponds to the region from nucleotide 3275 to 3643 in the lectomedin-lα sequence (SEQ ED NO: 22) and the sequence for EST M79057 corresponds to nucleotides 2561 to 2842 in lectomedin-lα. The BLAST search results indicated that both ESTs were more closely related to the sequence encoding rat latrophilin than to the nucleotide sequence encoding lectomedin-lα, further distinguishing lectomedin-lα from the rat protein and suggesting that the human ESTs may be more closely related to a putative human homolog of rat latrophilin. In view ofthe apparent relatedness between the human EST sequences and human lectomedin-lα, however, the M79057 and AA683020 ESTs were determined to represent unique lectomedin-2 and lectomedin-3 species, respectively. In an effort to isolate cDNAs encoding full length lectomedin-2 and lectomedin-3 proteins, primers were designed based on the EST sequences for both lectomedin-2 and lectomedin-3 to amplify probes for library screening. Primers for amplifying a lectomedin-2 sequence were NHlect2.5 (SEQ ED NO: 35) and NHlect2.3 (SEQ ED NO: 36), and primers for the lectomedin-3 sequence were Nhlct.5 (SEQ ED NO: 37) and NEDct.3 (SEQ ED NO: 38). NHect2.5 GGGCCTCACCTGGGCTTTCGGCCTCCTC SEQ ED NO. 35 NHect2.3 GGACTCGTGCCCCCACGCGTGTCAGCAC SEQ ED NO: 36 Nhlct.5 CCAACAAGACCCAT ACCAGCTGTG SEQ ED NO: 37 Nhlct.3 CTGAGTCTTGTCGATCCCGACC SEQ ED NO: 38 PCR was carried out using a Clontech human brain Marathon-Ready™ cDNA library as template. Reaction conditions included an initial incubation at 94°C for five minutes, followed by 25 cycles at 94°C for 30 seconds, 55°C for 30 seconds, and 72°C for 30 seconds, followed by a final extension step of 72°C for 7 minutes and cooling to 4 °C in a Perkin-Elmer GeneAmp PCR System 9700. The resulting PCR products were gel purified using low melting point agarose (Gibco/BRL) and a QQIIAAGGEENN ® ® ggeell eexxttrraaccttiioonn kkiitt aaccccoorrddiinngg ttoo tthhee mmaannuuffaaccttuurreerr''ss ssuuggggeesstteedd pprroottooccol. The ® purified aamr plification products were separately cloned into vector pCRII with a TA ® ® . . CClloonniinngg 1 kit (Invitrogen), and sequencing was carried out to identify errors associated with PCR. Probes for cDNA library screening were prepared by purifying EcoRI ® fragments from the pCRII clones. The lectomedin-2 digestion products provided two fragments, 274 and 158 bp, and the 274 bp fragment was purified. The lectomedin-3 digestion resulted in a 297 bp EcoRI fragment. ® A human fetal brain cDNA library in the LAMBDA ZAP II vector was purchased from Stratagene (La Jolla, CA). Approximately 50,000 pfu were plated on twenty 150 mm LBM agar plates with LΕ392 E. coli. Plates were inverted and incubated at 37 °C overnight. The next day, the plates were chilled at 4°C for two ® hours before preparing filter replicas. Amersham Hybond N + nylon transfer membrane filters, with a diameter of 132 mm and a removal rating of 0.45 μm, were used to prepare two replicas of each plate. Filters were soaked in denaturing solution for two minutes, soaked in neutralizing solution for two minutes, and UV crosslinked ® in a Stratagene UV Stratalinker 2400. Filters were prehybridized overnight at 65° C with 20 filters in 80 ml of prehybridization solution. Hybridization probes were prepared by labeling the EcoRI fragments with 32 P-dCTP and 32 P-dTTP (800 Ci/mmol each, NΕN Life Sciences Products) using a random priming kit (Boehringer Mannheim GmbH, Germany). The labeled probes were added to 20 ml hybridization solution per 20 filters and hybridization was carried out at 65 °C overnight. The filters were washed the next day and air dried before autoradiography at -70 °C for one to three days. Once films were developed, positive plaques were picked and removed to 500 μl of phage diluent buffer including one drop of chloroform. Dilutions ofthe positive plaques were prepared and plated on 100 mm LBM agar plates. The plates were screened a second time as described above using 82 ® mm Amersham Hybond N + filters, except that only one set of replica filters was prepared. Positive plaques from the second screening were screened for a third time to ensure that only positive plaques were picked for the phage rescue. ® Positive plaques were prepared using an Exassist /SOLR phage rescue system (Stratagene, La Jolla, CA) according to the manufacturer's suggested protocol. The rescue procedure produced E. coli colonies containing the DNA of interest cloned . ® . . . into a pBluescnpt SK vector with flanking EcoRI restnction sites. Plasmid DNA ® was purified using the Wizard Plus Miniprep Kit (Promega, Madison, WI) and digested with EcoRI to determine relative size. The resulting purified clones were analyzed by DNA sequencing at both the 5 ' and 3 ' ends. Ofthe positive clones identified by the probe derived from ΕST M79057 (lectomedin-2 probe) , several ofthe longest isolates were chosen for complete DNA sequence analysis. Two clones designated 2.1 (SΕQ D NO: 65) and 2.4 (SΕQ ΕD NO: 67) were found to comprise overlapping DNA sequences totaling 5611 bp including a complete open reading fame encoding 1470 amino acids. Ofthe clones identified with the AA683020 probe, all comprised sequences identical to clones derived from ΕST M79057. These results indicated that the AA683020 and M79057 ΕSTs represented non-overlapping regions from a single mRNA species. The two clones therefore were derived from a single lectomedin-2 gene. As originally determined, the polynucleotide encoding lectomedin-2 is set out in SΕQ ΕD NO: 57, and its amino acid sequence is set out in SΕQ ΕD NO: 58. Resequencing, however, resulted in the polynucleotide sequence set out in SΕQ ΕD NO: 69, with the deduced amino acid sequence set out in SΕQ ΕD NO: 70. The organization of various domains in the predicted polypeptide sequence of lectomedin-2 was related to that in lectomedin- 1. The approximately 851 amino acid extracellular domain of lectomedin-2 included a region with homology to the D-galactoside binding lectin-like domain (amino acids 36 to 131 of SΕQ ID NO.: 57), an olfactomedin-like domain (amino acids 135 to 325 of SΕQ ID NO: 57), three extracellular and three intracellular domains separated by seven transmembrane domains (approximately amino acids 852 to 1095 of SΕQ ID NO: 57) and a cytoplasmic region (approximately amino acids 1096 to 1470 of SEQ ED NO: 57). The cytoplasmic region of lectomedin-2 was most similar in length and sequence identity to lectomedin- lγ. Comparison ofthe overall polypeptide sequences of lectomedin- 1 γ and lectomedin-2 showed 62.5% amino acid identity. Comparison of the overall polypeptide sequences of lectomedin-2 and CERL showed 97.6% amino acid identity. 'These comparisons indicated that lectomedin-2 is more closely related by sequence to rat latrophilin than lectomedin- lγ. A strategy was designed to assemble the overlapping clones 2.1 and 2.4 in the mammalian expression vector pcDNA3 to produce full length lectomedin-2 open reading frame. Two primers (SEQ ED NOs: 61 and 62) were used to amplify a region ofcDNA clone 2.1. JD#1 ATATAAGCTTGCTGCCACCATGGCCCGC SEQ ED NO: 61 Lecto-3#31 ATGACCCACAGCCCGTTCTC SEQ IS NO: 62 Primer JD#1 (SEQ ED NO: 61) incoφorated aH ndlll site to facilitate cloning. The resulting 843 bp amplified product was digested with Hrødlll and BamΑ and a 535 bp DNA fragment was isolated. The 535 bp fragment from clone 2.1 was ligated with a 1912 bp BamVOJSa fragment from clone 2.1, a 2904 bp Sα/I/EcoRV DNA fragment from clone 2.4, and pcDNA3 (Invitrogen) previously digested with HindUl and EcoRV. The resulting plasmid was designated pCDNA3Lectomedin-2#l. Identification of Additional Lectomedin Species ® A BLAST search ofthe GenBank ΕST database with lectomedin-lα or lectomedin-2 as query sequences identified ΕST sequences identical to lectomedin- 1, ΕST sequences identical to lectomedin-2 and, ΕSTs that were significantly related to, but distinct from, both known lectomedins. See Table 1. Table 1 Additional Lectomedin Snecies Lectomedin-3 T10363 (SEQ ED NO: 39), R19057 (SEQ ED NO: 40), Lectomedin-5 R50822 (SEQ ED NO: 41) Lectomedin-6 W03697 (SEQ ED NO: 42) Lectomedin-7 H18951 (SEQ ED NO: 43) Lectomedin-8 AA769730 (SEQ ED NO: 44) Lectomedin-9 C 17798 (SEQ ED NO: 45) Lectomedin- 10 Z44961 (SEQ ED NO: 46) Lectomedin- 11 AA369669 (SEQ ED NO: 47) Lectomedin- 12 AB011122 (SEQ ED NO: 48) One of these unique lectomedin ESTs (GenBank Accession No: R50822) was derived from clone #37438. Clone #37438 was purchased and its DNA sequence completely determined. The polynucleotide sequence for clone #37438 is set out in SEQ ED NO: 59, and the encoded amino acid sequence is set out in SEQ ED NO: 60. The 3' sequence of clone #37438 is comprised of an untranslated region preceded by a predicted coding sequence for a protein with significant amino acid homology to the cytoplasmic domains of lectomedin- lγ and lectomedin-2. The 5' end ofthe sequence of clone #37438 was unrelated to the lectomedins, but was identical to the nucleotide sequence for a tRNA synthetase. This clone may represent a partially spliced mRNA or it might be a cloning artifact. The cDNA clone #37438 was used to generate a labeled probe to screen approximately one million clones from a human fetal brain cDNA library by techniques standard in the art. Hybridization was carried out at 43 °C in the presence of 45% formamide and filters were washed in 0.1X SSC at 68°C for 90 minutes. Positive clones identified were isolated to homogeneity and partial sequence analysis was carried out with eleven ofthe clones. The DNA sequence of one clone (clone #11) was determined to have 3' sequences identical to clone #37438 and 5 'sequences within the upstream coding sequences similar to, but distinct from, lectomedin- 1 and lectomedin-2. The nucleotide sequence for clone #1 1 is set out in SEQ ID NO: 71 , and its deduced amino acid sequence is set out in SEQ ED NO: 72. As clone #1 1 was a partial cDNA lacking an initiating methionine and 5' untranslated region, experiments were carried out in an attempt to identify additional sequences in the cDNA. RACE cloning was carried out as follows. The 5' cDNA sequence of clone #1 1 was obtained by RACE PCR using • a Human Fetal Brain Marathon-Ready cDNA Library Kit (Clontech) according to the manufacturer's suggested protocol. The primers used in the RACE PCR were designed from the 5' end of lectomedin-3 clone #11. JDRL3#6 GGAGGTTGTTAACTGTCTCGACCATTGCC SEQ ED NO: 73 JDRL3#5 GGACATAGGCTCTGCAAGAGCGCTCTC SEQ ED NO: 74 ® Resulting fragments were subcloned into a pCR2.1 -TOPO vector using a TOPO TA ® Cloning Kit (Invitrogen) according to the manufacturer's protocol. Ofthe resulting RACE clones, none contained a complete open reading frame, a 5' untranslated sequence, and a region that overlapped with the sequence in clone #11. One ofthe products, TAL3(6-5#1) (SEQ ED NO: 75), was chosen to generate a probe to screen for cDNA clones containing the desired sequences. The deduced amino acid sequence for TAL3(6-5#1) is set out in SEQ ED NO: 76. Clone TAL3(6-5#1) is a RACE PCR sequence that contained 2156 bp of 5' sequence (untranslated and translated with a ® predicted methionine start) in a pCR2.1 -TOPO vector. Clone TAL3(6-5#1) was digested with Hwdlll and resulting fragments were separated on a 1% low melting point agarose gel. A 1256 bp fragment was ® excised from the gel, the DNA purified using a QIAquick Gel Extraction Kit (QIAGEN) according to the manufacturer's suggested protocol, and the 1256 bp DNA fragment was labeled with 32 P by random primer method. Screening was carried out on a human fetal brain cDNA library by the same method except that the filters were baked in a vacuum oven at 80° C for 1.5 hr and the prehybridization solution consisted of 5X SSPE, 45% formamide, 5X Denhardt's solution, and 1% SDS. Prehybridization and hybridization was carried out at 45°C. The screening resulted in 21 double positives. One of these 21 was designated clone 17-1 which included 2205 bp as set out in SEQ ED NO: 77. The deduced amino acid sequence for clone 17-1 is set out in SEQ ED NO: 78. Nucleotide sequencing of clone 17-1 resulted in identification of 5' untranslated sequences, an initiating methionine codon, Kozak consensus sequence and an overlap of 287 bp with clone #11. Combined, the sequences from clone #11 and clone 17-1 provided a complete open reading frame for a lectomedin species distinct from lectomedin- 1 and lectomedin-2, and this new species was designated lectomedin- 3. The nucleotide and amino acid sequences for lectomedin-3 are set out in SEQ ED NOs: 79 and 80, respectively. Example 2 Recombinant Expression of Lectomedin Polypeptides Lectomedin-lα A. Expression vectors encoding lectomedin isoforms were constructed by combining DNA fragments from clone 3.3 and RACE3.3 described above. In one approach, both clone 3.3 and RACE3.3 polynucleotides are first modified in the overlapping regions by insertion of a silent mutation to introduce a S cl restriction site. PCR is employed using primers (SEQ ED NOs: 25 and 26) to amplify a 5' sequence from the RACE3.3 cDNA template that changes G to C at position 1455 to create the desired restriction site. In amplification ofthe RACE3.3 fragment, the 5 ' primer (SEQ ED NO: 26) is designed based on sequences at the ATG start codon; the primer introduces a BamHI restriction site to facilitate cloning and a Kozak consensus start sequence. 5 ' -TCTTCAGCTGAGCTCTTCAAAACC SEQ ED NO: 24 5'-GGTTTTGAAGAGCTCAGCTGAAGA SEQ ED NO: 25 5 -CAGCAGGGATCCACCATGGTGTCTT- CTGGTTGCAGAATGCGAAGTCTGTGG SEQ ID NO: 26 5 -GACGATGACGCGGCCGCCTATTAAAGAC- TTGTAACCAGCTGCATTTGTCCTTCTC SEQ ED NO: 27 In amplification of the clone 3.3 DNA with primers set out in SEQ ID NOs: 24 and 27, the 3' primer is based on sequences at the stop site of translation and is designed to introduce a Notl restriction site. The resulting amplification products, a RACE3.3 fragment with a 5' BamHl site and a 3' Sαcl site, and a clone 3.3 DΝA with a 5'SαcI site and a 3' Notl site, are digested with appropriate enzymes, ligated together, and cloned into the mammalian expression vector pcDΝA+3, (Invitrogen, Carlsbad, CA) previously digested with BamHl and Notl. B. As an alternative approach, a lectomedin- lα-encoding DΝA is generated using PCR with the 5' primer used to amplify RACE3.3 described above and the 3 ' primer used to amplify the clone 3.3 DΝA also described above. In the PCR, both RACE3.3 and clone 3.3 DΝA are combined with the two primers. After an initial denaturing step, the RACE3.3 and clone 3.3 DΝA will anneal across the overlapping regions and the double stranded region will serve as primers in the first extension that produces a complete double stranded lectomedin-lα DΝA. Subsequent amplifications will result from extension from the 5' and 3 ' primers. The amplification product is then purified, digested with BamHl and Notl, and inserted into the pcDΝA vector previously digested with the same enzymes. C. In another approach, an expression vector encoding lectomedin-lα was constructed in a two step procedure. First, PCR was carried out using a Xbal fragments of clone 3.3 and primers 3.3.24 (SEQ ED NO: 52) and Lecto 3' express (SEQ ED NO: 27) along with Taq polymerase. CCTACCACAGCTGTGACAATAACTTCTTCAGCTGAGC SEQ EDNO: 52 A second PCR was carried out using an EcoRI fragment of RACE 3.3 as template DNA and primers Lecto 5' express (SEQ ID NO: 26) and Lectoό (SEQ ED NO: 25) ® with Vent polymerase (New England Biolabs, Beverly, MA). The two amplification products were purified, denatured, and annealed. Because the two fragments overlap in a region of approximately 100 nucleotides, annealing results in a partially double stranded molecule spanning the entire lectomedin-l α coding region. Extension with Taq polymerase first produces a double stranded lectomedin- 1 α coding region. The double stranded molecule was then amplified using primers in SEQ ID NOs: 26 and 27. The SEQ ED NO: 26 primer was designed to introduce a BamHl restriction site, followed by a Kozak consensus start site. The resulting amplification product was digested with Notl and BamHl, and the lectomedin- 1 α fragment was gel purified. The fragment was ligated into pcDΝA3 (Invitrogen, Carlsbad, CA) previously digested with BamHl and Notl. Sequence analysis ofthe resulting plasmid, designated pcDΝA3 Lectomedin- lα#2, indicated that several errors were introduced in the amplification process. The correct lectomedin-lα coding sequence was constructed from regions of pcDNA3 Lectomedin- lα#2 without enors ligated to fragments of RACE3.3 and clone 3.3 as follows. A 166 bp HindϊWBgl fragment from pcDNA3 Lectomedin- lα#2, a 628 bp BglttJBstXl fragment from RACE3.3, and a 775 bp BstXUApal fragment from ® pcDNA3 Lectomedin- lα#2 were ligated in the presence of pBluescript KS+ (pBSKS) (Stratagene) previously digested with ifatXI and Apal. The resulting plasmid was designated pB SKSlectoHindIII/ApaI# 14. In another reaction, a 306 bp Apal/EcόRl fragment from clone 3.3 and a 2486 bp EcoRI/EcoRI fragment from clone 3.3 were ligated in the presence of pBSKS previously digested with Apal and EcoRI. The resulting plasmid was designated pB SKSlecto 1 alphaΕcoRI/ApaI#6. Plasmids pNEF6 and pDEF2 encode promoter regions and a 5' intron from the gene encoding Chinese hamster ovary elongation factor 1, in addition to neomycin (G418) resistance for selection. Construction of pNEF6 and pDEF2 was carried out as follows. Plasmid pEFl/XN was generated by ligation of an 11 kb NotVXbάl fragment from pSK/EF1.12 (WO 98/49289, published November 5, 1998, incorporated herein by reference), having the Xbά site blunt ended with Klenow polymerase, with a 2.22 NotVS al fragment from pDC31 (WO 98/49289). Plasmid pNEF3 was generated by ligation of a 4.19 kb SalUNsil fragment (the Nsil site blunt ended with Klenow polymerase) from pSKEFl.7 (WO 98/49289) with a 7.96 kb SalUPmel fragment from pNEFl (WO 98/49289). . Plasmid pNEF5 was constructed with a 9.2 kb AscVNotl fragment from pNEF3 and an 11 kb Ascl/Notl fragment from pEXl/XN. Plasmid pNEF6 was constructed by ligation of a 19.7 kb XbaUAsp71% fragment from ρNEF5 with a 0.844 kb Xbal/Aspl S fragment from pRc/CMV (Invitrogen). A 736 bp NoWHinάlll fragment (including the intron sequence) was isolated from pDEF2 and combined with a 1571 HindlHIApal fragment (including the Kozak sequence, translation start site, and coding region for amino acids 1 to 515) from pBSKSlectoHindIII/ApaI#14, a 3714 bp ApaVXbal fragment (encoding amino acids 516 to 1177 of lectomedin-lα and including a stop codon and untranslated sequences) from pBSKSlectolalphaEcoRI/Apa#6, and pNEF6 previously digested with Xba and Notl. The resulting plasmid was designated pΝEFόLectomedinl A#3.1. Lectomedin-lβ and Lectomedin-lγ Clone 15.3.1 and clone 71509 were separately amplified with primers lecto3.3.10 and 3.3.19. TCAGACACTCATACTGCTGTG SEQ EDNO: 49 CACAGTCCACAACTTGCAC SEQ ED NO: 50 The resulting amplification products were digested with Stul and Ncol, and a 113 bp fragment from 15.3.1 (lectomedin-lβ) and a 210 bp fragment from 71509 (lectomedin- lγ) were purified. Each fragment was separately ligated into pBSKSlectolalphaEcoRI/ApaI#6 previously digested with St and Ncol. The resulting plasmids were designated pBSKSlectolbetaEcoRI/ApaI#7 and pBSKSlectolgammaEcoRI/ApaI#6. To create a lectomedin-l β expression plasmid, the reaction described above for construction of the lectomedin-lα expression plasmid was repeated except that a 2586 bp ApaVXbal fragment from pBSKSlectolbetaEcoRL ApaI#7 was substituted for the 3714 bp ApaVXbal from pBSKSlectolalphaEcoRl/ApaI#6 to provide plasmid pNEF6LectomedinlB#4.2. To create a lectomedin-lγ expression plasmid, the same lectomedin-lα reaction above was carried out except that a 2683 bp ApaVXbal fragment from pBSKSlectolgammaEcoRI/ApaI#6 was substituted for the 3714 bp ApaVXbal from pBSKSlectolalphaEcoRI7ApaI#6 to provide plasmid pNEF6LectomedinlG. Expression of a soluble Lectomedin-1 Ig fusion protein An expression construct was also prepared in parental vector pDC37 encoding a soluble, truncated form of lectomedin-1 as a fusion protein with human immunoglobulin Gl hinge and constant heavy chain regions 2 and 3 [hinge CH2-CH3] sequence [Sadhu, et al, Cell Adhesion and Commun. 2:429-440 (1994)]. Plasmid pDC37, encoding human VCAM-1 with human IgGl hinge-CH2 coding sequences, is a derivative of pDC31 generated by digestion with Sail, filled in with Klenow polymerase, and blunt end ligated to eliminate the Sail site. Plasmid pDC37/VCAMl.Igl.2c was digested with HwdELI and Sail and a fragment lacking the NACM-1 coding region was isolated. The isolated HindϊLVSall fragment was ligated with a 1571 bp HindUVApal fragment from pcDΝA3Lectomedin-la#2 and an amplification product from clone 3.3 prepared using primers lecto Sal Ig (SEQ ED NO: 51) and 3.3.24 (SEQ ED NO: 52). lecto Sal Ig SEQ ED NO: 51 GACGCTGGTCGACTAGGTGGCTGCATGCACACGTTGTTCG 3.3.24 SEQ ED NO: 52 CCTACCACAGCTGTGACAATAACTTCTTCAGCTGAGC Primer lecto Sal Ig generated a unique Sail site in the amplification product (after codon 811 of lectomedin-1) to permit in-frame ligation to IgGl coding sequences. The resulting plasmid was designated pDC37Lecto.Ig#7. A 736 bp NotVHinάlll fragment from pDEF2 was ligated with a 1571 bp HindlWApallλ fragment (encoding the Kozak sequence, start site, and amino acids 1 to 515 from lectomedin-lα) from pcDNA3 Lectomedin- 1 a#2, a 1788 bp ApaVXbal fragment (encoding amino acids 516 to 81 1 from lectomedin-1 fused to IgG sequences) from pDC37Lecto.Ig#7, and pDEF14 previously digested with Notl and Xbά . The resulting plasmid was designated pDEF14Lecto.Ig#2. Plasmid pDEF14Lecto.Ig#2 was transfected into DΗFR " DG44 CΗO cells and stably transfected cells were selected. Example 3 Characterization of Recombinant Lectomedin Polypeptides Characterization ofthe protein expression level in recombinant cells is carried out using polyclonal antisera (produced as described in Example 8), and functional analysis, with respect to latrotoxin and/or galectin-3 binding and or release of secretory granule contents, is performed as described herein. In initial characterization, Chinese hamster ovary (CΗO) cells were transfected by standard methods (i.e., calcium phosphate or cationic lipids) with lectomedin-lα expression construct. After 48 hours incubation, the cells were lysed in ® PBS containing 1% Triton X-100 and protease inhibitors, and proteins in the detergent soluble fraction were separated by SDS-PAGE. After transfer to nitrocellulose membrane, the blot was incubated with rabbit #7234 antiserum immunospecific for lectomedin-1 (generated against amino acids 432-852 as immunogen, a fragment that is not specific for either lectomedin-lα, -lβ, or lγ). Immunoreactivity was detected using a goat anti-rabbit IgG (conjugated with horseradish peroxidase) followed by chemiluminescence detection and exposure to X- ® ray film (using a Renaissance detection kit, ΝEΝ Life Sciences, Boston, MA). For functional characterization, secretory cells ofthe endocrine system are employed which readily accept DΝA constructs by transfection. Cell lines useful in functional characterization include, for example, mouse anterior pituitary corticotroph continuous cells (AtT20; ATCC CCL 89), rat pancreatic islet insulinoma continuous cells (RinM5F), or human pituitary somatotroph continuous cells (GΗ3; ATCC CCL 82.1). After an appropriate amount of time to allow protein synthesis, incubation of the transfected cells with alpha-latrotoxin, or another ligand, is followed by detection of stimulated secretion of proteins using enzyme-linked immunosorbant assay or radioimmunoassay (RIA). For example, increased secretion from the exemplified cells lines is accomplished through detection of adrenocorticotrophic hormone (ACTH) release from AtT20 cells, insulin release from RinM5F cells, or growth hormone release from GH3 cells. In addition, since lectomedin-1 is a G-protein coupled receptor, ligand binding would be expected to trigger intracellular second messenger effector pathway activity changes such as, for example, increased production of cyclic AMP (cAMP) or changes in intracellular calcium concentration. Changes of these types are measured by standard techniques, for example, RIA detection of cAMP or fluorescence detection of calcium binding indicators (i.e., Fura 2). An exemplary alpha-latrotoxin binding assay has been previously described [Meldolesi, J. Neurochem. 35:1559-1569 (1982), Petrenko, e al, EMBO J, 9:2023 -2027 ( 1990)] . Cells are transfected with either vector DNA alone (control cells) or a lectomedin 1 -encoding expression plasmid (assay cells). Both assay and control cells are homogenized in buffer (120 mM NaCl, 4.7 mM KCl, 1.2 mM each MgSO 4 , K 2 HPO 4 and CaCl 2 , 20 mM Na 2 HPO 4 -HCl, pH 7.4, and 10 mM glucose) and protein concentrations are determined by standard methods. Known amounts of protein from control or transfected assay cell membranes are spotted on nitrocellulose paper and placed in separate wells of a 24 well dish. The paper is rinsed once with buffer containing 100 mM KCl, 2 mM CaCl 2 , and 20 mM Tris, pH 7.7, and incubated for one hour in the same buffer supplemented to 1.5% (w/v) with bovine serum albumin (BSA) (blocking buffer). Solutions of blocking buffer containing from 0.1 to 1.2 nM of 125 I-labeled alpha-latrotoxin, labeled to a specific activity of 1500 to 2000 Ci/mmol, without or with a large excess (100 nM) of unlabeled toxin are incubated for thirty minutes with the immobilized protein. The paper is rinsed three times with 1 ml of blocking buffer over a 20 minute time period and counts per minute remaining are determined with a gamma counter. Nonspecific binding is determined to be the value of radioactive counts remaining after incubation of labeled toxin in the presence of a large excess of unlabeled toxin. Specific counts are converted to nanomoles of toxin bound per milligram of protein spotted and the data is plotted as nanomoles bound toxin versus nanomoles free toxin. The data are converted to bound toxin divided by free toxin versus bound toxin to derive a Scatchard plot for number of binding sites (a linear plot being the expected result for a single toxin binding site on the receptor). In additional characterizations, the lectomedin fusion protein ® lectomed -1 α-Ig (Example 2) was purified using protein A Sepharose (Amersham Pharmacia Biotech, Piscataway, NJ) affinity chromatography and conditioned growth media derived from one of two clones designated G10 and E10. Media was loaded onto the column which was then washed extensively with 50 mM Tris, pH 7.5, 50 mM NaCl. Protein was eluted in buffer containing 50 mM citric acid, pH 4.0, and 50 mM citric acid, pH 3.0. The majority ofthe protein eluted in the pH 3.0 buffer. Protein fractions were pooled, neutralized with 1 M Tris, pH 8.0, and dialyzed against PBS. Purified protein was filtered, aliquoted, flash frozen and stored at -70 °C. Amino terminal sequencing indicated that the mature amino terminus of the protein was a phenylalanine residue at position 26. This observation indicated that the recombinant protein was recognized and cleaved by a signal peptidase in the CHO cells and that the amino terminus was not blocked. Size exclusion chromatography suggested a protein with a molecular weight of approximately 650 kDal as compared to the molecular weight determined on SDS PAGE of approximately 170 kDal. The gel filtration result suggested that four monomers combined to produce the 650 kDal protein. Treatment ofthe protein with N-glycosidase F, O-glycosidase, and/or neurominidase (Boehringer Mannheim) in 10 mM Na^-IC^ (pH 6.8), 5 mM EDTA, ® 0.25% Triton X-100, 0.5% SDS, and 0.5% β-mercaptoethanol (BME), at 37°C, resulted in reduction of protein molecular weight. After treatment with N-glycosidase F alone, monomeric protein molecular weight was approximately 130 kDal. After treatment with N-glycosidase F, O-glycosidase, and neuraminidase, monomeric protein molecular weight was approximately 125 kDal. These observations suggest that the observed SDS PAGE molecular weight may be attributable to approximately 40 kDal N-linked carbohydrate and approximately 5 kDal O-linked carbohydrate. Example 4 Ligand Affinity Chromatography In an attempt to isolate a ligand for lectomedin- 1 , an affinity column was generated with immobilized lectomedin- 1. In short, 10 mg of purified lectomedin- ® 1 α-Ig (Example 2) was coupled to CNBr-activated Sepharose 4B resin (AmershamPharmacia) according to the manufacturer's suggested protocol. Greater than 96% ofthe lectomedin protein was coupled to the resin. A detergent extract was prepared from human spleen (3.48 g wet ® weight). Tissue was homogenized in 15 ml buffer containing 1% Triton X-100, 25 mM Tris, pH 8, 150 mM NaCl, 5 mM iodoacetamide, 5 mM EDTN 1 mM phenylmethylsulfonyl fluoride (PMSF), and 1 μg/ml pepstatin and aprotinin using a Waring blender. Homogenization was carried out at low speed. The resulting homogenate was cooled on ice for one hour and centrifuged at 100,000 x g for 60 min. The supernatant (approximately 120 mg total protein) was mixed with the sLecto-Hg- coupled resin with rotation overnight at 4°C. The resin was drained and washed extensively with 10 mM Tris (pH 8), 150 mM NaCl, and 10 mM Tris (pH 8), 1 M NaCl. Protein was eluted with five bed volumes of 100 mM D-lactose, 10 mM Tris, pH 8.0, 150 mM NaCl. Five equal fractions were collected. The resin was further eluted with four bed volumes of 100 mM glycine, pH 2.0, and four equal fractions were collected and neutralized with 1 M Tris, pH 8.0. The resin was then neutralized in 10 mM Tris, pH 8.0/150 mM NaCl. Fractions from the resin were analyzed by SDS-PAGE and bands of approximately 95, 71, 55 and 30 kDal were detected. Fractions with the highest protein yields were spin concentrated ® (Ultrafree 10, Millipore, New Bedford, MA) and proteins were separated with 12% SDS-PAGE. Coomassie staining revealed four prominent bands in the lactose eluate of approximately 30-32, 55, 70, and 80-95 kDal. Bands were excised from the gel, rinsed twice in 50:50 acetonitrile:water, and stored at -70°C until sequence analyses were performed. Sequence results indicated that the 30-32 kDal protein was galectin- ® 3 (also called Mac-2, GenBank Accession No: gl06937), the 55 kDal protein was ® fibrinogen γ A chain (GenBank Accession No: g71827) and the 80-95 kDal protein was immunoglobulin mu chain constant region. Galectin-3 is synthesized by numerous immune cell populations and epithelia, and is a major non-integrin laminin binding protein [Perillo, et al, J. Mol. Med. 76:402-412 (1998)]. Recent observations indicated that galectin-3 was expressed in vessels in early atherosclerotic lesions in association with infiltrating monocytes. Expression was not detected in normal vessels. Expression was also detected in aortic smooth muscle cells in culture, as well as in tissues from animals • following a hypercholesterolemic feeding regimen and post balloon angioplasty [Arar, et al, FEBS Letts.430:307-311 (1998), Nachtigal, et al, AmJ.Pathol 752:1199-1208 (1998)]. Galectin-3 stimulates normal fibroblast proliferation, neural cell adhesion, and neurite outgrowth [Inohjara, et al, Exp. Cell. Res. 245:294-302 (1998); Pesheva, et al, J. Neurosci. Res. 5-^:639-654 (1998)]. The binding results from lectomedin affinity chromatography, in view of the art, suggest that secretion of galectin-3 by infiltrating macrophages and activated smooth muscle cells during atherogenesis and binding to lectomedin-1 expressed on smooth muscle cells of vascular tunica media may be required for smooth muscle proliferation in atherosclerosis. [Ross, Nature 362:801-809 (1993)]. Previous work has indicated that circulating components ofthe thrombolytic pathway, including fibrinogen, are associated with chronic vascular disease (i.e. , hypertension, atherosclerosis). Studied showed that circulating fibrinogen levels may be elevated in hypertensive patient populations. These observations suggest a role for lectomedin-1 in various vascular disease states. Example 5 Northern and Dot Blot Analysis In an attempt to assess human lectomedin-1 α expression, Northern blot analysis was performed using a commercial multi-tissue blot (Clontech, Palo Alto, CA) with RNA derived from various human tissue sources. The probe used was a 531 bp BstXl fragment derived from the extracellular region of clone 3.3 (bases 1860 to 2350 in SEQ ID NO: 7). Hybridization was carried out in Express-Hyb ™ Solution (Clontech) at 68°C for two hours; the final wash was carried out at 68°C in 0. IX SSC for one hour. Results indicated expression of two predominant transcripts of 6.6 and 7 kb. The highest levels of expression were detected in spleen, prostate, and lung. Lower signals were in duodenum, placenta, thymus, testis, colonic mucosa, heart, and liver. Lowest levels were found in skeletal muscle, kidney, pancreas, and brain. No signal was observed in ovary and peripheral blood leukocytes. In an attempt to more fully elucidate the extent bf lectomedin tissue expression, dot blot analysis was carried out using an RNA Master Blot (Clontech) representing RNA from a wide range of human tissues. In assessing lectomedin-1 expression, a 32 P-labeled probe was generated from the HindllVApal fragment of pB SKSlectoHindIII7ApaI# 1 (Example 2) by the random priming method. A human RNA Master Blot (Clontech) representing normalized quantities of poly A + RNA was incubated with the probe overnight at 65 °C according to the manufacturer's suggested protocol. The blot was washed at 65 °C in 2X SSC, 1% SDS and 55° in 0.1X SSC, 1%SDS. The washed blot was exposed to film at -70° and to a Phosphorimager® (Molecular Devices,Inc, Redwood City, CA) screen for digital quantitation. Table 2 below lists in descending order the relative signals detected by the Phosphorimager®. Dot blot analysis was also carried out using the RNA Master Dot Blot (Clontech) described above to determine tissue distribution of lectomedin-2 and lectomedin-3. Probes to the 3' ends of lectomedin-2 and lectomedin-3 cDNA were ® generated by restriction digestion. Clone 2.4 in pBluescript SK (+/-) (described in Example 1) containing 3649 bp of 3' lectomedin-2 was digested with EcoRI and Pstl and the resulting fragments were separated on a 1% low melting point agarose gel ® (Gibco/BRL). A 1042 bp fragment was excised and gel eluted using a QIAquick Gel Extraction Kit (QIAGEN). Clone #11 (Example 1) in a Bluescript SK (+/-) vector and containing 4622 bp of 3' lectomedin-3 was digested with EcoRI and the resulting fragments were separated on a 1% low melting point agarose gel. A 1004 bp band was excised and the fragment eluted from the gel as described above. Sequences for both probes were submitted through the NCBI BLAST Search program and subjected to Mac Vector DNA alignments to ensure that they would not give false positives. Both probes were labeled with 32 P by random primer method and unincoφorated nucleotides were removed using a G-25 spin column (Boehringer Mannheim). The dot blot was probed first with the lectomedin-2 fragment and washed as described above according to the manufacturer's protocol. The blot was exposed to a Phosporimager® screen for three 3 days. Results were analyzed on a STORM 860 Phosphorimager® and are shown in Table 2 below. Values of relative intensity in arbitrary units are provided from highest to lowest. The dot blot was stripped of lectomedin-2 probe according to the manufacturer's protocol and exposed to a Phosphorimager® screen for one day to insure removal of the probe. Analysis on a STORM 860 Phosphorimager® showed very little leftover signal. The blot was then probed with the lectomedin-3 fragment according to the manufacturer's protocol, washed as described above, and exposed to a Phosphorimager® screen for two hours. Results were analyzed as above and are depicted in Table 2 below. Background lectomedin-1 signals (defined as no detectable signal) were observed is spinal cord, bone marrow, skeletal muscle, subthalamic nucleus, fetal thymus, and peripheral blood leukocytes tissues. Background levels of lectomedin-2 expression were observed in putamen, spinal cord, caudate nucleus, substantial nigra, temporal lobe, cerebral cortex, cerebellum, thalamus, hippocampus, frontal lobe, medulla oblongata, subthalamic nucleus, and skeletal muscle tissues. Background levels of lectomedin-3 expression were observed in ovary, liver, pancreas, fetal liver, skeletal muscle, fetal spleen, peripheral blood leukocyte, and fetal thymus. Table 2 Lectomedin Tissue Expression in Arbitrary Units LECTOMEDIN- 1 LECTOMEDIN-?. LECTOMEDIN-3 lung 641 lymph node 328332 fetal brain 26626 fetal kidney 569 small intestine 282324 small intestine 23880 placenta 551 appendix 241772 lymph node 20318 fetal lung 499 spleen 165162 amygdala 16494 small intestine 462 stomach 157076 putansen 16461 thyroid 428 trachea 123383 temporal lobe 16121 fetal heart 425 bone marrow 112736 substantial nigra 15834 ovary 419 salivary gland 69893 appendix 15337 heart 389 thymus 60250 occipital lobe 15285 fetal brain 367 lung 47451 stomach 14993 liver 346 colon 25509 spinal cord 13312 adrenal 339 thyroid gland 20196 caudate nucleus 12679 spleen 337 fetal spleen 19589 thalamus 11874 appendix 331 kidney 17813 whole brain 11665 occipital lobe 328 mammary gland 14762 subthalamic nucleus 11217 salivary 325 ovary 13255 spleen 11066 pituitary 309 pancreas 12950 frontal lobe 8551 fetal spleen 268 adrenal gland 11332 hippocampus 8534 prostate 259 fetal brain 10992 cerebral cortex 8110 fetal liver 258 aorta 10893 cerebellum 7910 trachea 257 liver 10812 bone marrow 7119 stomach 253 placenta 10675 trachea 6775 whole brain 247 peripheral leukocyte 10064 medulla oblongata 6356 aorta 234 prostate 9471 adrenal gland 6247 pancreas 196 human DNA (500 ng) 9314 aorta 6044 kidney 190 fetal liver 9110 placenta 5303 temporal lobe 181 1 bladder 8896 fetal kidney 4667 amygdala 180 1 uterus 8863 uterus 4452 putamen 175 pituitary gland 8472 salivary gland 4394 thymus 174 occipital lobe 8218 fetal lung 3753 cerebral cortex 168 heart 8063 testis 3694 frontal lobe 162 human DNA (100 ng) 7747 lung 3639 uterus 160 fetal kidney 7457 thymus 3525 lymph node 149 fetal thymus 7367 colon 3470 caudate nucleus 148 fetal lung 7301 human DNA (500 r ig) 2999 mammary 146 whole brain 7140 heart 2823 bladder 143 amygdala 6743 prostate 2203 cerebellum 142 fetal heart 6272 fetal heart 2068 colon 136 testis 5618 mammary gland 1931 medulla oblongata 132 kidney 1602 testis 129 thyroid gland 1598 hippocampus 128 bladder 1502 substantiu nigra 126 pituitary gland 1315 thalamus 122 Example 6 In situ Hybridization In order to verify and extend results from Northern analysis, in situ hybridization was carried out using various human tissue sections. Probes for in situ hybridization analysis were prepared as follows. Clone 3.3 was engineered by PCR to include a Sacl site near the 5 ' end ofthe cDNA by changing a G nucleotide to C at position 1459 ofthe composite sequence. A 626 bp SacVEcoRl fragment was prepared and subcloned into pBSSK (Stratagene, La Jolla, CA). The resulting plasmid was linearized with either EcoRI or Sαcl. The ends ofthe Sαcl linearized DNA were made blunt by standard procedures using T4 DNA polymerase. Linear DNAs were used to generate 35 S-labeled sense or antisense strand probes for in situ hybridization with tissue sections from spleen, lung, prostate, heart, thymus, duodenum. The results obtained from hybridization experiments were inconclusive due to high background with sense strand control probe. In another approach to localizing the lectomedin-1 mRNA two other fragments ofthe lectomedin-1 cDNA were subcloned into the pBluescript ® vector. A 1238 bp BamHUSacl fragment of lectomedin-lα (SΕQ ΕD NO: 1) was subcloned. A representative clone including this fragment was designated as probe BS. A 2855 bp BamHUXbal fragment of lectomedin-lα (SΕQ ΕD NO: 1) was subcloned and a representative clone was isolated and designated as probe BX. 35 S-labeled sense and antisense probes from both BS and BX were prepared by methods standard in the art and hybridized with tissue sections from human brain occipital cortex, cerebellum and thalamus; interventricular septum, sino-atrial node and atrium ofthe heart; small intestine, spleen, lung, prostate, adrenal gland and pancreas. Specific signals were observed with the antisense BS probe in cardiac myocytes (heart), endocrine secretory cells ofthe adrenal cortex, occipital cortex neurons and cerebellar Purkinje neurons, granule layer neurons and some molecular layer neurons. The antisense BX probe produced similar patterns except for the presence of specific signals in a subset of secretory cells ofthe prostate. Example 7 Human Lectomedin Chromosomal Localization The contiguous lectomedin-lα cDNA deduced from combining clone 3.3 and RACE3.3 sequences was used as a query to search the NCBI Sequence- Tagged Sites (STS) database in an attempt to map the chromosomal location of a gene encoding lectomedin-l . Two STSs were identified, designated SHGC-36772 and WI-1 1936, which were mapped to chromosome 1 by radiation hybrid mapping techniques. The STS WI-1 1936 mapping has been further refined to chromosome locus lp31. In an effort to identify the chromosomal localization ofthe gene for ® lectomedin-2, the full length nucleotide sequence was used to query the GenBank high throughput genomic sequences nucleotide database using the BLAST algorithm. Results indicated that a portion of chromosome 17 had identity with a portion ofthe lectomedin-2 DNA sequence. Query ofthe human Genemap '98 at NCBI for the localization of this region of chromosome 17, showed that the lectomedin-2 gene mapped to chromosome 17p 11.1 -q 12. To identify the chromosomal localization ofthe gene for lectomedin-3, an accession number query (using EST R50822) ofthe Unigene database at the National Center for Biotechnology Information (NCBI) was carried out. The results identified a cluster of ESTs, including R50822 that mapped to human chromosome 4. Refinement ofthe localization was carried by searching the human GeneMap '98 out at NCBI, which showed that EST the cluster containing R80522 was assigned to 4ql2- 13.3. Example 8 Preparation of Antibodies to Lectomedin Generation of Poly clonal Antisera With Extracellular Lectomedin-1 Fragments An E. coli expression vector was constructed encoding the extracellular region of lectomedin-lα (residues 432 to 852 of SEQ ED NO: 1) as a fusion protein with a biotinylated tag at the amino terminus. The plasmid, designed "Biolectolst ECD" was constructed as follows. PCR primers "lecto-1 " and "lecto-2" (SEQ ED NOs: 31 and 32, respectively) were used to amplify a 1283 bp fragment of clone 3.3 (nucleotides 1508- 2772 in SEQ ED NO: 9 which encodes the amino acid sequence from residue 432 to residue 852 of SEQ ED NO: 10). This region of the lectomedin-1 polypeptide is approximately 69% identical with latrophilin. primer lecto- 1 SEQ ED NO : 31 5^TACAACI IQGGCACAACTGTAGCTGG primer lecto-2 SEQ ED NO: 32 5 '-TACAAGj^ICIAGCAGATAGCCAGGCAAACAAGGG Primer lecto- 1 introduced an Ncol restriction site (underlined above) in the amplification product and primer lecto-2 introduced a BglH restriction site (underlined above) and a translational termination site. The amplified fragment was subcloned into plasmid arabiolb previously digested with Ncol and Bglll to form plasmid Bio 1 ecto 1 stECD . The plasmid arabio 1 b contains the Salmonella typhimuriu arabinose promoter and araC gene, as well as the biotin transferase gene [Kashishian, et al, J. Bio. Chem. 273:27412-27419 (1998)]. The expression product ofthe final construct provides a fusion protein of approximately 55 kDa with the biotin tag at the Ν-terminus, and the lectomedin-1 amino acids 432 to 852 at the C-terminus. The plasmid BiolectolstECD was transformed into E. coli using standard procedures and single colonies were isolated and grown for plasmid preparation. A culture including the desired plasmid was grown at 30 °C in LB/carbenicillin supplemented with biotin (4 μM) and induced in the presence of arabinose (0.5%) for 16 hours. Bacteria were collected by centrifugation and lysed with hen egg lysozyme (10 μg/ml) in TEN buffer (50 mM Tris-HCl, pH 7.5 at 25°C, 0.5 mM EDTA, 0.3 M NaCl) on ice for 15 minutes. After incubation on ice, NP-40 detergent was added to 0.2% final concentration and the resulting mixture sonicated briefly on ice. Insoluble material was removed by centrifugation at 15,000 x g for ten minutes, after which the pellet washed five times with the additional of TEN buffer followed by sonication and centrifugation. The final pellet was solubilized in 2X sample loading buffer for preparative SDS-PAGE separation. A major band of 55 kDa was detected after treating the gel for 30 minutes in 0.4 M KCl. The 55 kDa band was excised from the gel and the fusion protein eluted in dialysis tubing using 0.5% SDS-PAGE running buffer. The collected ® protein was concentrated, spin-dialyzed (30,000 MW cutoff Ultrafree Centrifugal Filter Device; Millipore Coφ. Bedford, MA), and stored. The purified protein was used to immunize two rabbits to generate antisera according to well known procedures. Briefly, two New Zealand white rabbits (designated #7234 and #7278) were prebled to obtain preimmune serum and then immunized with 250 μg of purified BiolectolstECD fusion protein emulsified with complete Freund's adjuvant. The rabbits were boosted repeatedly with 250 μg of purified fusion protein in incomplete Freund's adjuvant. After the first immunization, three boosts were given at one month intervals, a fourth boost was administered at a three month interval, and a fifth boost was given following an additional one month interval. Blood was drawn by ear vein puncture two weeks after the second, third, fourth, and fifth boosts to determine antibody titers. Immunoprecipitation was carried out with the resulting polyclonal sera using extracts from tissues/cell lines, including brain cortex, lung, spleen, liver, skeletal muscle, hippocampus, and prostate carcinoma cell line PC-3 (ATCC, CRL 1435). Protein species having molecular weights of 200, 180, 170, and 70 kDa were detected which may have represented full length proteins, proteolytic fragments, or isoforms of lectomedin including the α, β, and γ proteins . Serum obtained from rabbit #7234 after the fifth boost was subjected to antigen-specific affinity chromatography by methods standard in the art. Briefly, 10 ml of 0.45 or 0.8 microfiltered serum (100 xg supernatant) adjusted to 10 mM Tris, pH 7.5, was incubated with lectomedin- lα-Ig agarose beads for 16 hours at 4°C with rotation. The beads were drained and washed with 20 bed volumes of 0.5 M NaCl, 10 mM Tris, pH 7.5, until absorbance OD 2g0 reached 0.03. Bound antibody was eluted with five bed volumes of 100 mM glycine, pH 2.5. The eluates were collected as 0.5 ml fractions and neutralized with 1 M Tris, pH 8. The lectomedin- lα-Ig agarose beads were neutralized with 50 mM Tris, pH 7.5/150 mM NaCl and stored at 4°C in the same buffer supplemented with 0.1% thimerosol. Fractions were analyzed by SDS- PAGE for the presence of immunoglobulin heavy and light chains. The peak fractions were pooled, the buffer was exchanged with PBS, and the volume reduced by 90%. The final product was mixed with an equal volume of sterile glycerol, aliquoted, flash frozen, and stored at -70°C. until use. Generation of Polyclonal Antisera With Synthetic Lectomedin-1 Cytoplasmic Peptides Peptides specific to the carboxy terminal cytoplasmic regions of α, β, and γ isoforms of lectomedin-1 were synthesized as immunogens for producing polyclonal antisera in New Zealand White rabbits. The peptides were designed from the DNA sequence in the cytoplasmic region of lectomedin lα (SEQ ED NO: 53), lectomedin lβ (SEQ ED ON: 54), and lectomedin lγ (SEQ ED NO: 55). Cys-Leu-Gln-Asp-Leu-Tyr-His-Leu-Glu-Leu-Leu-Leu-Gly-Gln-Ile-Ala SEQ ED NO: 53 Cys-Thr-Arg-Thr-Ser-Ala-Arg-Tyr-Ser-Ser-Gyl-Thr-Gln-Asp-Ile-His SEQ ED NO: 54 Cys-Glu-Gly-Asp-Val-Arg-Glu-Gly-Gln-Met-Gln-Leu-Val-Thr-Ser-Leu SEQ ED NO: 55 Peptides comprising the carboxy terminal regions ofthe related lectomedin-2 (SEQ ED NO: 63) and lectomedin-3 (SEQ ED NO: 64) proteins were also synthesized. Cys-Pro-Gly-Pro-Asp-Gly-Asp-Gly-Gln-Met-Gln-Leu-Val-Thr-Ser-Leu SEQ ED NO: 63 Cys-Pro-Glu-Gly-Ser-Ser-Lys-Gly-Pro-Ala-His-Leu-Val-Thr-Ser-Leu SEQ ED NO: 64 The peptides synthesized for immunization were individually conjugated to Keyhole ® Limpet Hemocyanin (KLH) (Imject , Pierce) according to the manufacturer's suggested protocol. Rabbits were prebled, and 100 μg of conjugated peptide in complete Freund's adjuvant was injected per rabbit, two rabbits per isoform. At three week intervals, the rabbits were boosted with the same dose of antigen in incomplete Freud's adjuvant. Animals were bled 10 days after the third injection and serum titer determined by ELISA. ® Briefly, Immulon 4 (Dynax Technologies, Chantilly, VA) plates were coated with unconjugated peptide at 2 μg/ml. Plates were blocked with 0.5% fish skin gelatin and washed. Serial dilutions ofthe pre-immune serum and test bleeds from each rabbit were incubated on the peptide-coated plates. After washing, goat anti- rabbit-horseradish peroxidase (HRP) conjugated secondary antibody was added. The plates were washed and signal detected by tetramethyl benzidine (TMB) (Sigma) reagent. Serum from rabbits #6484 and #6453 immunized with the lectomedin- 1 β peptide showed reactivity three-fold greater than pre-immune serum at a 3000-fold dilution. Serum from rabbits #6868 and #6307 immunized with lectomedin-lγ showed three-fold greater reactivity over pre-immune serum at a 3000-fold dilution. Serum from rabbits #7347 and #6490 immunized with lectomedin-lα, showed three-fold greater reactivity at a 200-fold dilution. In view of these results, a second lectomedin-lα peptide (SEQ ED NO: 56) was synthesized and the immunization protocol described above was repeated with two additional rabbits (#8511 and #7880). Cys-Ser-Arg-Ile-Arg-Arg-Met-Tφ-Asn-Asp-Thr-Val-Arg-Lys-Gln-Ser SEQ ED NO: 56 Serum from rabbit #8511 showed reactivity three-fold over pre-immune serum at a 3000-fold dilution. Serum from rabbit # 7880 showed reactivity three-fold over preimmune serum at a 1000-fold dilution. Additional peptides comprising the carboxy termini of lectomedin-2 and lectomedin-3 (SEQ ED NOs: 63 and 64) were synthesized to screen for cross reactive antibodies recognizing similar epitopes located in the termini of lectomedin-lγ, lectomedin-2 and lectomedin-3. Briefly, the peptides in SEQ ED NOs: 63 and 64, as ® well as SEQ ED NOs: 53, 54, 55, and 56 were coated on separate wells of Immunlon 4 ELISA plates as described above. Purified IgG from rabbit #6868 was incubated with each peptide at 20 μg/ml and 2 μg/ml concentrations. IgG from rabbit #6868 cross reacted with both the lectomedin-2 peptide (SEQ ED NO: 63) and lectomedin-3 peptide (SEQ ED NO: 64). There was no cross reactivity with lectomedin-lα peptides (SEQ ED NOs: 53 and 56), or with lectomedin-lβ peptide (SEQ ED NO: 54). Total IgG from rabbit sera was purified using standard protein A affinity chromatography. Monoclonal Antibody Production In an attempt to produce monoclonal antibodies immunospecific for lectomedin polypeptides, the following procedure was carried out. Five 6 to 12 week old BALB/c mice were prebled on day 0 and immunized by subcutaneous injection with 20 μg of the lectomedin- 1 α, lectomedin- 1 β or lectomedin-lγ peptides (SEQ ED NOs: 53, 54, and 55) described above (60 μg total) in complete Freund's adjuvant. On Days 21, 41, and 62, each mouse was boosted with 10 μg of each peptide (30 μg total) in incomplete Freund's adjuvant. Test bleeds were drawn on day 72 and reactivity determined by ELISA against individual peptides as described in generation of polyclonal antisera, with the exception that specific mouse antibody was detected with a goat anti-mouse-HRP. Immune serum from all five mice showed reactivity to lectomedin-lβ and lectomedin-lγ peptides greater than pre-immune serum at a 12800-fold dilution. Serum from all ofthe mice showed modest reactivity to lectomedin-lα peptide. In an another approach to generate an immune response to lectomedin- lα, five additional mice were immunized with the second lectomedin-lα peptide (SEQ ED NO: 56) described above. Immune serum from each ofthe mice was tested for lectomedin-lα reactivity by ELISA (described above) prior to fusion and hybridoma cloning. The spleen of mouse #3411, and subsequently mouse #3413, was removed aseptically and a single-cell suspension was formed by grinding the spleen between the frosted ends of two glass microscope slides submerged in serum free RPMI 1640 (Gibco, Canada) supplemented with 2 mM L-glutamine, 1 mM sodium pyruvate, 100 units/ml penicillin, and 100 μg/ml streptomycin. The cell suspension ® was filtered with a sterile 70-mesh Nitex cell strainer (Becton Dickinson, Parsippany, New Jersey), and washed twice by centrifuging at 200 x g for five minutes and resuspending the pellet in 20 ml serum free RPMI. Thymocytes taken from naive Balb/c mice were prepared in the same manner. Approximately 2 x 10 s spleen cells were combined with 4 x 10 7 NS-1 cells (kept in log phase in RPMI with 11% fetal bovine serum [FBS] for three days prior to fusion). The cells were collected by centrifugation and the supernatant was aspirated. The cell pellet was dislodged and 2 ml of 37°C PEG 1500 (50% in 75 mM HEPES, pH 8.0) (Boehringer Mannheim) was added while stirring over the course of one minute, followed by the addition of 14 ml of serum free RPMI over seven minutes. The cells were centrifuged at 200 x g for 10 minutes, and after discarding the supernatant, the pellet was resuspended in 200 ml RPMI containing 15% FBS, 100 mM sodium hypoxanthine, 0.4 mM aminopterin, 16 mM thymidine (HAT) (Gibco), 25 units/ml EL-6 (Boehringer Mannheim), and 1.5 x 10 6 thymocytes/ml. The suspension was dispensed into ten 96-well flat bottom tissue culture plates (Corning, United Kingdom) at 200 μl well. Cells were fed on days 2, 4, and 6 days post-fusion by aspirating 100 μl from each well and adding 100 μl/well plating medium containing 10 U/ml EL-6 and lacking thymocytes. When cell growth reached 60-80% confluence (day 8 to 10), culture supematants were taken from each well and screened for reactivity to lectomedin-lα ® peptide (SEQ ED NO: 56) by ELISA as follows. Immulon 4 plates (Dynatech, Cambridge, Massachusetts) were coated at 4°C with 100 ng of immunogen in 50 μl 50 ® mM carbonate buffer, pH 9.6. Plates were washed with PBS with 0.05%, Tween 20 (PBST) and blocked 30 minutes at 37° C with 0.5% fish skin gelatin. Plates were washed as described above and 50 μl culture supernatant was added. After incubation at 37° C for 30 minutes, plates were washed as above, then 50 μl of horseradish peroxidase conjugated goat anti-mouse IgG(fc) (Jackson ImmunoResearch, West Grove, Pennsylvania) [diluted 1:10,000 in PBST] was added. Plates were incubated at 37°C for 30 minutes, washed with PBST and 100 μl of substrate, consisting of 0.1 mg/ml TMB (Sigma) and 0.15 ml/ml 30% H 2 O 2 in 100 mM citrate, pH 4.5, was added. The color reaction was stopped with the addition of 50 μl of 15% H 2 SO 4 . Absorbance at 450 nm was read on a plate reader (Dynatech). The fusion on mouse spleen #3411 was performed first and resulted in eight wells immunoreactive against the peptide in SEQ ED NO: 56. The fusion on mouse spleen #3413 resulted in 82 positive wells in the primary screen as described above. To determine the specificity ofthe positive wells to native lectomedin- lα, Western blotting and immunocytochemistry (ICC) were performed on the supernatant of ELISA-positive wells. Briefly, in Western blotting, a cell lysate from HEK 293 T cells transfected with a lectomedin-lα expression construct pNEF6LectomedinlA#3.1 (Example 2) was separated using 8% Novex® SDS-PAGE. Protein on the gel was transferred to a P VDF membrane in standard transfer buffer for 1 hour at 300 mA constant. The membrane was blocked for 1 hour in 20 mM ® <Ss Trizma base [Sigma], 150 mM NaCl, with 0.05% Tween , pH 7.2 (TBST) with 5% milk . Supematants from the positive wells were diluted 1 : 1 with TBST with 5% milk and incubated with the blot for 1 hour at room temperature. The blot was rinsed twice in TBST at room temperature for five minutes and peroxidase-conjugated goat anti- mouse antibody was added at 8 ng/ml in TSBT with 5% milk for 30 minutes at room temperature. The blot was rinsed in TBST four times for 5 minutes each wash and ® developed using the Dupont Renaissance Kit. For fusion of #3411, none ofthe supematants that recognized the lectomedin peptide (SEQ ED NO: 56) by ELISA recognized native lectomedin-lα by Western blot. The positive control polyclonal rabbit anti-lectomedin-lα antisera (affinity purified #7234), however, did recognize bands ofthe expected size on the blot. For fusion #3413, one ofthe 40 positive supematants tested stained bands having the expected size of native lectomedin-lα. This same supernatant gave a positive result in immunocytochemistry as described below. In the immunocytochemistry experiments, HEK 293 T cells transfected with pNEF6LectomedinlA#3.1 and vector control- transfected HEK 293 T cells were "spotted" onto microscope slides by standard cytospin methods. Cells were fixed in 4% paraformaldehyde and slides were stored at -20 °C until the assay. The day ofthe assay, slides were thawed, allowed to air dry, treated with cytoskeleton stabilizing buffer, (containing 100 mM sodium chloride, 2 mM magnesium chloride, 0.5 mM ® calcium chloride, 1% Triton -X100, 10 mM PIPES, pH 6.8, 200 mM sucrose and 4 mM vanadyl ribonucleoside) for two minutes at 4°C, and washed in TBST. In order to quench endogenous peroxide activity, slides were treated with 10% sodium azide/3% hydrogen peroxide in phosphate buffered saline for 15 minutes at room temperature. Slides were rinsed in TBST and blocked with 30% normal human serum/5% normal rat serum/2% bovine serum albumin in TBST for 30 minutes at room temperature. Avidin blocking solution (Vector Laboratories) was added for 15 minutes at room temperature and the slides were rinsed in TBST. Biotin blocking solution (Vector ® Laboratories) from the same Vector kit was added for 15 minutes at room temperature, after which fusion supematants were added without dilution for 1 hour at room temperature. Anti-tubulin was used as the positive control antibody at 1 :500 dilution with blocking reagent (above) and irrelevant mouse IgGl was used as the ® negative control. Slides were washed three times in TBST and ABC Elite reagent from the Avidin-biotin-peroxidase kit PK-6100 (Vector Labs) was added for 30 minutes at room temperature. Slides were washed twice with TBST, after which DAB Substrate Solution (Research Genetics) was added for 5 minutes to develop. Slides were counterstained with Gill's Hematoxylin (Sigma). For microscopic evaluation, slides were treated with cytoseal mounting medium (Stephens Scientific). Cells from the well that was positive in ELISA, Western blot, and immunocytochemistry were subjected to two rounds of cloning by limiting dilution to obtain a single cell line expressing the desired antibody. This clone was designated 334N. Example 9 Immunocytochemistry for Expression of Lectomedin Polyclonal antisera generated in rabbit #7234 (and affinity purified) as described above was used to determine lectomedin expression patterns in human and rat tissues. Human tissues were obtained from the National Disease Research Interchange (NDRI, Philadelphia, PA), including human brain (cortex and cerebellum), heart (septum and atrium), prostate, lung, liver, spleen, small intestines, adrenal gland, and artery (renal, pulmonary and subclavian). Aorta was obtained from the Pathological Determinants of Atherosclerosis in Youth (PDAY) Study, Louisiana State University Medical Center. Rat tissue was prepared using procedures well known and * routinely practiced in the art. Frozen tissues were embedded in OCT (Tissue-Tek), sectioned at 6 ® micron thickness, mounted onto Superfrost Plus (VWR Scientific) slides, and stored at -20 °C until the assay was performed. Paraffin-embedded, formalin-fixed tissues were stored at room temperature until the assay was performed. Prior to assay, frozen tissue was fixed in acetone for two minutes at 4°C, except for brain tissue which was fixed in ether for five minutes at room temperature. Paraffin was removed from the formalin-fixed tissue with two three-minute washes in each of xylene, 100% ethanol, 95% ethanol, and 70% ethanol. Endogenous peroxidase activity was quenched by incubating the fixed cryosections in buffer containing 0.1% sodium azide and 0.33% hydrogen peroxide in phosphate buffered saline (PBS) during a 15 minute incubation. All incubations were carried out at room temperature unless otherwise indicated. Slides were rinsed in TBST and blocked in a solution containing 30 % normal human serum albumin (Boston Biomedica), 5% normal goat serum (Harlan), and 2% bovine serum albumin (Sigma) in TBST for 30 minutes. Nonspecific binding was blocked using sequential 15 minute incubations with avidin and biotin blocking solution (SP- 2001, Vector Laboratories, Burlingame CA). Slides were rinsed in TSBT after each incubation. Primary antibody at concentrations ranging from 1 μg/ml to 5 μg/ml was applied to each section for one hour, after which sides were washed in TSBT three times. Biotinylated goat anti-rabbit antibody conjugated to peroxidase (Vector Laboratories) was diluted 1 :200 in blocking solution and applied to the slides for 30 minutes. Slides were washed for five minutes and incubated for 30 minutes with ABC ® Elite reagent (avidin-biotin-peroxidase kit PK-6100, Vector Labratories). Slides were washed twice for five minutes per wash in TSBT. Substrate solution (DAB substrate kit for peroxidase, Vector Labs) was applied to the slides and the desired color intensity was allowed to develop over approximately five minutes. The reaction was stopped with deionized water, and the slides were counterstained with Gill's hematoxylin (Sigma) solution, rinsed in water, dehydrated in ethanol, and mounted with Cytoseal mounting medium (Stephens Scientific) for light microscopic evaluation. In human brain cortex, labeling with 7234 sera was detected in a subset of neurons (including large and small pyrimidal neurons), granule cells, and smooth muscle cells ofthe vasculature. Human cerebellum staining with 7234 sera was localized to Purkinje neurons and neurons ofthe granular cell layer. Human heart (septal and atrial sections) showed cardiomyocyte immunoreactivity, most prominently at cardiac myocyte cell junctions transverse to the plane ofthe contractile apparatus called intercalated disks. In double label experiments using a commercially available connexin antibody (Zymed, San Francisco, CA), which stains connexin found at the intercalated disks, the previous results were confirmed as results indicated that connexin antibody and 7234 antisera staining co-localized on the intercalated disks. Sections of human prostate showed weak stromal cell labeling and cytoplasmic skeletal muscle staining. Lung staining was found in cartilage and some bronchial smooth muscle cells, with certain cells staining more strongly than others. The medulla ofthe adrenal gland showed strong positive staining. Human liver, spleen, and small intestines exhibited a non-specific pattern of immunoreactivity. Human aorta showed immunoreactivity with 7234 sera in the vessel wall that was primarily located in the tunica intima (lumenal muscle layer) and tunica media (intermediate muscle layer). Thoracic aorta, pulmonary artery, and renal artery each showed similar staining patterns. When compared with staining with an antibody to smooth muscle α-actin (an accepted marker for smooth muscle cells), lectomedin- 1 immunoreactivity was found primarily in the same cells (i.e., smooth muscle cells). Staining in rat tissues with 7234 sera demonstrated similar patterns as observed in human tissues. In brain, some neuronal populations and the smooth muscle ofthe vasculature were stained. In the heart, intercalated disks, cardiomyocytes, and vascular smooth muscle all showed immunoreactivity. Example 10 Localization of Lectomedin-1 and Galectin-3 in Atherosclerotic Tissues Previous observations (Example 4) indicated that lectomedin binds galectin-3 in vitro. In view of this result and reports by others that galectin-3 is expressed in atherosclerotic tissue, immunocytochemistry was carried out on normal , and atherosclerotic tissue in order to determine if lectomedin-1 and galectin-3 expression co-localized in the diseased tissue. Immunocytochemistry was carried out as described in Example 9 using aorta from normal individuals which was compared to aorta from the PDAY study showing early stage atheromatous disease and to aortas from endarterectomies of patients with later stages of atherosclerotic disease. Antigen localization was investigated with antibodies to lectomedin-1 (7234 affinity purified rabbit serum), galectin-3 (rat anti-galectin-3 monoclonal antibody), a vascular smooth muscle cell marker (murine anti-alpha actin monoclonal antibody), and a macrophage marker (murine anti-CD68 monoclonal antibody). In normal aorta, lectomedin-1 immunoreactivity was found mostly associated with cells expressing the smooth muscle cell marker within the tunica media and tunica intima. Occasional lectomedin-1 positive cells were visible in association with cells that stained positive with the macrophage marker. Galectin-3 staining was negative in the normal tissue. In early atherosclerotic lesions, in addition to vascular smooth muscle staining as seen in normal tissue, lectomedin-1 staining was visible in the thickened tunica intima. This staining overlapped with staining for the macrophage marker and galectin-3. This region showed no α-actin smooth muscle cell marker staining. More advanced lesions showed lectomedin-1 immunoreactivity that localized in regions of the vessel wall with macrophages that were also galectin-3 positive. In these lesions, galectin-3 staining was visible in adjacent regions with cells that stained positive for the smooth muscle cell actin marker. In early lesions, therefore, the staining pattern of lectomedin-1 was in association with macrophages expressing galectin-3. In later stage lesions, lectomedin-1 staining was found in association with both macrophages and galectin-3 positive proximal vascular smooth muscle cells. Example 11 Localization of Lectomedin-1 and Galectin-3 in ApoE knockout Mice Mice deficient in ApoE (gene knockout, KO) [Plump, et al, Cell 77:343-353 (1992)] were fed a high cholesterol diet for up to 25 weeks. Normal mice or ApoE KO's at 10, 20 and 25 weeks of high cholesterol diet were euthanized and aortas prepared for histopathology. The sections were stained for lectomedin-1 (using 7234 affinity purified polyclonal sera, which cross reacts with the mouse protein), galectin-3, alpha actin (to identify smooth muscle cells), and Mac-3 (to identify macrophages). As seen in the normal human aortic tissue, immunoreactivity for lectomedin-1 in normal mice co-localized to the smooth muscle cells ofthe vessel wall. Neither Mac-3 nor galectin-3 immunoreactivity was detected. Aortas from ApoE KO mice fed a hypercholesterolemic diet exhibited intimal thickening and foam cell (macrophage) accumulation, which are hallmarks of atherosclerosis in humans. Lectomedin-1 was expressed in vascular smooth muscle cells, foam cellsa, and neuronal cells. Galectin-3 immunoreactivity was found to increase with time in regions ofthe vessel wall that overlapped with the Mac-3 and lectomedin-1 immunoreactivities. Unlike in human tissues, however, intensity ofthe lectomedin signal in the ApoE KO mice appeared to be reduced in those areas where galectin-3 signals were highest. Example 12 Glycosidase Treatment of Lectomedin-lα In order to determine if lectomedin-1 is a glycoprotein, the purified protein was treated with various glycosidases and changes in electrophoretic mobility examined. Lectomedin- lα-Ig, prepared as described in Example 2, was treated with glycosidases of differing specificities to determine the types, if any, of covalently attached oligosaccharides. The apparent molecular weight of monomeric lectomedin- lα-Ig was determined to be about 160 kDa on SDS-PAGE. Treatment of lectomedin- 1 α-Ig with PNGase F, which breaks the β-aspartamido-glucosaminyl bond of all known N-linked oligosaccharides, decreased the apparent molecular mass of lectomedin- lα-Ig by about 40 kDa, indicating that lectomedin- lα-Ig is predominantly N-glycosylated. Lectomedin- lα-Ig was also treated with sialidase, and then with endo-α-N-acetylgalactosaminidase, in order to determine if lectomedin- lα-Ig is O-glycosylated and whether the O-linked glycans had simple structures. Endo-α-N-acetylgalactosaminidase releases non-sialylated Galβl-3GalNAc core 1 disaccharides, but not more complex O-linked glycans, from serine or threonine residues. Treatment with sialidase increased the elctrophoretic mobility by about 6 kDa. Subsequent addition of endo-α-N-acetylgalactosaminidase increased the mobility of lectomedin-1 α-Ig about 5 kDa more than sialidase treatment, suggesting that O-linked oligosaccharides were simple structures that were susceptible to the enzyme and that the majority ofthe glycans of lectomedin- lα-Ig contained sialic acid. Lectomedin- lα-Ig was also treated with endo-β-galactosidase, which hydrolyzes internal β-1-4 linkages between galactose and N-acetylglucosamine (Galβl-4GlcNAc) in extended unbranched poly-N-acetyllactosamine chains. This enzyme did not alter the mobility of lectomedin- lα-Ig, suggesting either the absence of poly-N-acetyllactosamine chains, or that these chains are substituted with, for example, fucose. O-sialoglycoprotein endopeptidase specifically cleaves proteins that are O-glycosylated on serine and threonine residues. The preferred substrates are mucin-like clustered O-sialylated glycans. Lectomedin- lα-Ig was cleaved into two predominant species, one band having a molecular mass of about 110 kDa and a second broad band at about 45 kDa, indicating that lectomedin- lα-Ig contains a mucin-like domain. The apparent molecular weight of PNGase F-, sialidase-, and endo-α-N-acetylgalactosaminidase-treated lectomedin- lα-Ig was about 117 kDa, which was in close agreement with the predicted molecular mass of 116 kDa by amino acid composition. Example 14 Lectomedin-1 Binding to Galectin-3 In view ofthe results observed in Example 4, 10 and 11, lectomedin-1 binding to galectin-3 was further investigated using two approaches. A. Galectin-3 Binding to Lectomedin-1 α-Ig on Sepharose Beads Galectin-3 was produced using the mouse galectin-3 bacterial expression plasmid pIN III ompA2-Galectin-3 [Agrwal, et al, J. Biol. Chem 26-5: 14932-14939 (1993)]. Recombinant protein was expressed and purified from freshly transformed JA221 cells [Agrwal, supra]. The carbohydrate recognition domain (CRD) of galectin-3 was obtained by treatment with collagenase D, followed by purification using saccharide-specific affinity chromatography [Agrwal, supra]. The purity ofthe recombinant protein was greater than 95% as determined by SDS-PAGE followed by Coomassie staining. Lectomedin- 1 α-Ig (Example 2) was covalently linked to CNBr-activated Sepharose® 4B resin (AmershamPharmacia) according to the manufacturer's suggested protocol. The coupling efficiency was about 95% with about 2.0 mg of lectomedin- lα-Ig conjugated per ml of wet beads. Lectomedin-1 α-Ig-Sepharose (50 μl beads) was incubated with galectin-3 (20 μg) or CRD-galectin-3 (10 μg) for 30 minutes at 4°C in binding buffer containing 150 mM NaCl, 10 mM β-mercaptoethanol, and 25 mM Tris, pH 7.5. The beads were washed extensively with binding buffer and bound protein was eluted with SDS sample buffer and analyzed by SDS-PAGE. Where indicated, binding experiments were carried out in the presence of 100 mM α-lactose in binding buffer. Galectin-3 and CRD-galectin-3 both bound lectomedin- lα-Ig- containing beads and lactose completely inhibited this binding. Binding of CRD galectin-3 to lectomedin- lα-Ig was also detected, and inhibition by lactose indicated that galectin-3 bound primarily to one or more carbohydrate moieties on lectomedin- lα-Ig. B. Galectin-3 Binding to Lectomedin Using Surface Plasmon Resonance ® All binding experiments were performed at 25° C on a BIAcore 2000 (Biacore, Inc., Piscataway, NJ) with HEPES-buffered saline (150 mM NaCl, 3 mM EDTN 10 mM HEPES, pH 7.4) and 0.005% P20 surfactant as running buffer. A purified rabbit anti-human IgG Fc polyclonal antibody (ImmunoPure, Pierce, Rockford, EL) was covalently coupled to research grade CM5 sensor chips (Biacore) via primary amine groups using the Amine Coupling Kit (Biacore) according to the manufacturer's suggested protocol. The antibody was coupled for four minutes at 50 μg/ml in 10 mM sodium formate (pH 4.0). Immobilized antibody was regenerated with minimal loss of lectomedin- lα-Ig binding activity after injecting 100 mM HCI over the surface for three minutes. Lectomedin- lα-Ig was immobilized on the sensor surface indirectly through the carboxy terminal immunoglobulin portion of lectomedin- lα-Ig. When lectomedin- lα-Ig was injected over a sensor surface to which the antibody had been covalently coupled, there was an increase in response indicating binding. Typically, about 800 response units (RU) of lectomedin- lα-Ig were captured for binding studies. Following lectomedin injection, galectin-3 (two-fold serial dilutions, 500 to 7.8 μg/ml in running buffer) was injected briefly over the lectomedin-bound surface and over control VCAM-1 -Ig or chitinase-Ig sensor surfaces. The response attained equilibrium within seconds ofthe beginning of each injection and returned to baseline within seconds ofthe end ofthe injection. Because the BIAcore detects changes in the refractive index, the difference between the response detected with injection over the lectomedin surface compared with the response detected with injection over the control surface represents the actual binding of galectin-3 to lectomedin- lα-Ig. Results indicated that 50 to 2500 RU of galectin-3 specifically bound to lectomedin-1 when tested in the 7.8 to 500 μg/ml galectin-3 concentration range. There was no binding when galectin-3 was injected in the presence of lactose. Consistent with this result, binding ofthe carbohydrate recognition domain (CRD) of galectin-3 alone to lectomedin- lα-Ig was also detected. As with results from the binding to lectomedin-1 on Sepharose® beads, these results indicated that the lectin-domain of galectin-3 recognized one or more carbohydrate moieties on lectomedin-lα. Example 15 Effects of Glycosidases on Lectomdin-lα Binding to Galectin Previous, results indicated that galectin-3 binding to lectomedin-1 was carbohydrate dependent (above). In an attempt to identify the carbohydrate epitopes required for galectin-3 binding, lectomedin- lα-Ig was treated with glycosidases of differing specificities (above) and galectin binding measured on a BIAcore. Briefly, similar response units of control and glycosidase-treated protein were captured onto the sensor surface using rabbit polyclonal antibody to the carboxy terminal immunoglobulin portion of lectomedin- lα-Ig and binding of galectin-3 was determined. The effect of glycosidase treatment was determined by comparing the response units of galectin-3 binding to different glycosidase-treated lectomedin-1 α-Ig surfaces to a control surface of bound, sham-treated lectomedin-lα (defined as 100% binding). N-glycanase treatment of lectomedin- lα-Ig reduced galectin-3 binding by about 35%. In contrast, treatment with neuraminidase increased binding by 15%, suggesting that some ofthe galectin-3 -binding epitopes were either exposed upon neuraminidase treatment, or the binding affinity to a previously exposed epitope(s) was increased. Binding to lectomedin- lα-Ig following neuraminidase and O-glycanase reduced galectin-3 interaction by 18%, however, treatment with O-glycanase alone resulted in only a modest reduction in binding. This observation indicated that majority ofthe O-glycans on lectomedin that bind galectin-3 are sialylated and resistant to O-glycanase if not de-sialylated. O-sialoglycoprotein endopeptidase cleaved about 45 kDa from the amino terminal portion of lectomedin- lα-Ig and reduced binding of galectin-3 by more than 90%, suggesting that the majority ofthe galectin-3 recognition sites are located on the amino-terminal portion of lectomedin. Treatment of lectomedin- 1 α-Ig with N-glycanase, neuraminidase, and O-glycanase completely abolished galectin-3 binding. Combined, these results indicated that galectin-3 binds lectomedin-1 in a multivalent manner at both N- and O-linked glycans. In terms of biological significance, binding of this type can cross-link cell surface receptors and provide a mechanism for signal transduction. Example 16 Lectomedin-2 Expression in HEK293T Cells Human kidney 293T cells were used to transiently express full length lectomedin-2. The day before cells were transfected, two 100 mm tissue culture dishes were seeded with 1 x 10 6 cells in Minimum Essential Media (with Earl's salts and sodium bicarbonate) supplemented with 10% fetal bovine serum, 1 mM sodium pyruvate, 2 mM L-glutamine, and 100 units/ml penicillin-streptomycin. The cells were placed in a 5% CO 2 incubator overnight 37 °C. Transfection was carried out the next day using the SuperFect transfection reagent (QIAGEN, Valencia, CA) according to the manufacturer's suggested protocol. One dish of cells was transfected with 10 μg full length lectomedin-2 DNA in a pcDNA 3 vector (pcDNA3Lectomedin-2#l, described in Example 1) vector. The other dish was transfected with 10 μg pcDNA 3 vector alone as a negative control. Cells were placed in a 5% CO 2 incubator for 48 hours 37 °C. After 48 hours, the media was aspirated and the cells were washed twice with 4 ml cold calcium- and magnesium-free PBS (CMF-PBS). The transfected cells were harvested with 1 ml REPA lysis buffer (IX PBS, 1% Igepal CA-630 (Sigma), 0.5% sodium deoxycholate, 0.1% SDS supplemented with 0.1 mg/ml PMSF and 0.1 mg/ml aprotinin protease inhibitors) per 100 mm dish. Igepal CA-630 was formerly referred to as Nonidet 40. Cells were collected and placed on a rotating rack at 4 C C for 15 minutes to lyse the cells. Lysate was centrifuged using a benchtop centrifuge at 12,500 φm at 4°C for 15 minutes. The supernatant was collected and stored at -20 °C. Protein concentration ofthe lectomedin-2 lysate was determined to be approximately 1250 μg/ml. The protein concentration ofthe empty pcDNA 3 vector lysate was determined to be approximately 1050 μg/ml. Expression of lectomedin-2 was detected using SDS-PAGE and Western Blotting. Two 10 μl aliquots (approximately 10 μg each) of pcDNA 3 lysate and two 10 μl aliquots (approximately 10 μg each) of lectomedin-2 lysate were separated on an 8% NO VEX gel (San Diego, CA) at 150 volts. Before loading the gel, 10 μl of 2X Tris-glycine/100 mM DTT loading buffer was added to each sample and one sample from each lysate was heated at 100°C for 5 minutes. Western blotting was performed using 1 μg/ml of a rabbit anti-lectomedin-lγ polyclonal antisera #6868 as a primary antibody and a anti-rabbit peroxidase (Boehringer Mannheim) as a secondary antibody. ECL reagents (NEN Life Sciences) were used for detection according to the manufacturer's protocol. Radiography revealed a band of approximately 160 kD representing full length lectomedin-2 in the lysate that was not heated. An intense bright band around 55 kD was also observed. The 160 kD band was not present in the negative controls or the heated lysate. The 55 kD band was not present in the negative controls, but was present in heated lectomedin lysate to a lesser degree than that observed in the non-heated lysate. Example 17 Two Hybrid Screening In an attempt to identify cellular binding partners of lectomedin, two hybrid assays were carried out as previously described and using cytoplasmic lectomedin sequences to identify DNAs encoding binding partners from a brain library. Full-length lectomedin-1 β cytoplasmic tail was generated by PCR using a primer (SEQ ID NO: 81) designed on sequences encoding the membrane-proximal region ofthe protein, beginning at the codon for alanine (residue 1073 corresponding to nucleotides 3433-3435 in SEQ ID NO: 3) and a primer (SEQ ED NO: 82) including the stop codon at the 3' end. The 5' primer introduced an EcoRI site and the 3 ' primer introduced a BamHl site in the amplification product. PCR template DNA was an EcoRI I Apal 3' fragment of lectomedin-lβ in pBSKS. 5' primer: TCATCAGAATTCGCTCTCCAAAAGAAAGTACGA SΕQ ΕD NO: 81 3' primer TCATCAGGATCCTCAGTGAATGTCCTGTGTGCC SΕQ ΕD NO: 82 The amplification product was digested with EcoRI and BamHl and cloned into vector pAS2-l (Clontech), which expresses protein encoded by a cloned DNA as a fusion with the Gal4 DNA binding domain. This Gal4 vector is designed for use with Matchmaker cDNA libraries (Clontech) cloned into pACT2 (Clontech), a vector that expresses proteins encoded by library sequences as a fusion with the Gal4 DNA activation domain. The target library in E. coli was a 7ιol-(dT)15-primed and directionally cloned Matchmaker cDNA library (Clontech) prepared from the whole brain of a 37 year old Caucasian male. The two hybrid assay was carried out according to the manufacturer's suggested protocol. Specific interactions with the bait construct were assayed by colorizing filter-lifts, and by liquid assay, according to the manufacturer's suggested protocol (and modified as described herein). A total of eight different target proteins were identified by sequencing the target inserts, and the sequences were compared to those in GenBank . ® A first target sequence corresponded to GenBank clone KIAA0445 (Accession No: 3413852) having a complete open reading frame of 3941 bp encoding ® 1313 amino acid residues. KIAA0445 is described in GenBank as being derived from human brain, but no biological function has been assigned [Seki, et al, DNA Res. 4: 345-349 (1997)]. The KIAA0445 clone included nucleotides 5121 to 6459 ofthe full length clone, previously described to include 6471 bp, with nucleotides 2018 to 5959 comprising the open reading frame. A second target clone corresponded to a hepatitis delta antigen-interacting protein (dip A, Accession No: U63825) with an open reading frame of 608 bp encoding a protein having 202 amino acid residues. The protein is described to be homologous to hepatitis delta antigen and to modulate HDV genomic replication [Brazas, et al, Science 274: 90-94 (1996)]. The dip A sequence has been reported to consist of 868 bp including an open reading frame from nucleotide 29 to nucleotide 637. The full length dip A clone identified here included nucleotides 1 to 868 ofthe full length sequence. A third target protein was identified as a kinesin-related protein, KΕF3C (Accession No: AF018164). KEF3C, with an open reading frame of 2382 nucleotides encoding a protein of 793 amino acids, is a microtubule-dependent motor protein from human brain that is involved in intracellular transport and mitosis. The gene is located on chromosome 2ρ23 [Sardella, et al, Genomics 47405-408 (1998)]. A related protein, KEFIC, is postulated to be important in exocytosis, suggesting a similar biological activity for KEF3C. KEF3C is encoded in a sequence having 3775 nucleotides, with nucleotides 155 to 1610 comprising the open reading frame. The KEF3C clone identified in the two hybrid assay consisted of nucleotides 1358 to 1924. A fourth protein G0S3 (FOSB) (Accession No: L49169) is described to be a GO/G1 regulatory switch protein isolated from human blood and a component of the API transcriptional regulator. These biological activities suggest that interaction of G0S3 with a signaling component of lectomedin-lβ could lead to transcriptional activation and/or targeting of expressed products. The G0S3 protein of 338 amino acids is encoded by an open reading frame of 1016 bp [Siderovski. et al. DNA Cell Biol. 9: 579-587 (1990); Heximer, etal. DNA Cell Biol. 75:1025-1038 (1996)]. The G0S3 coding region comprises nucleotide 594 to 1610 in a complete 3775 nucleotide sequence. The clone identified in the screening included nucleotides 1028 to 3744 of the full length sequence. A fifth target protein showed homology to AMY (Accession No: D82343), a neuron-specific amyloid protein isolated from a human neuroblastoma cell line [Yokoyama, et al, DNA Res. 3:311-320 (1996)]. AMY is a 135 amino acid protein encoded by an open reading frame of 407 bp. The full length AMY-encoding polynucleotide has been reported to include 1009 nucleotides, with nucleotides 286 to 693 comprising the open reading frame. The clone identified here comprised nucleotides 238 to 985 ofthe full length sequence. A sixth target protein was identified as RanBpm (Accession No: AB008515), a 500 amino acid protein isolated from a human B-cell library and encoded by an open reading frame of 1475 bp. When overexpressed, RanBpm causes ectopic microtubule nucleation [Nakamura, et al, J Cell Biol. 143: 1041-52 (1998)]. RanBpm interaction with lectomedin-lβ could result in cytoskeletal reorganization. The complete RanBpm sequence has been reported to be 2346 nucleotides in length, with nucleotides 436 to 1938 encoding the full length protein. The RanBpm sequence identified in the two hybrid assay included nucleotides 100 to 2346 ofthe full length polynucleotide, and therefore represented the complete open reading frame. A seventh target was identified as the ADA3-like protein that is part of the PCAF histone acetylase complex, but may also be active in the same or another biological activity outside of this complex [Ogryzko, et. al, Cell 94: 35-44 (1998)]. The 432 amino acid AD A3 -like protein (Accession No: AF069733) is encoded by an open reading frame of 1298 bp. The ADA3-like protein is encoded by a polynucleotide comprising 1299 bases, with nucleotides 436 to 1938 comprising the open reading frame. The incomplete AD A3 -like coding polynucleotide identified in this assay included nucleotides 138 to 1299 ofthe complete sequence. The eighth target protein was identified in the database from a human genomic clone 18 A 13 (Accession No: AC007198) containing 100 kb. The clone identified in the two hybrid screen encoded only a short peptide, and the sequence may encode a cryptic activation domain. The complete open reading frame for this protein has not been identified, but the sequence identified in the assay encoded a fusion protein of 46 amino acids in-frame with the Gal4 DNA-activation domain. While the present invention has been described in terms of specific embodiments, it is understood that variations and modifications will occur to those skilled in the art. Accordingly, only such limitations as appear in the appended claims should be placed on the invention.

Claims: What is claimed is: 1. A purified and isolated human seven transmembrane receptor lectomedin polypeptide or a fragment thereof, said polypeptide comprising extracellular lectin-binding, olfactomedin-like, and mucin-like domains; said polypeptide 6omprising the amino acid sequence set out in SEQ ED NO: 70 or fragment thereof. 2. A purified and isolated human seven transmembrane receptor lectomedin polypeptide or a fragment thereof, said polypeptide comprising extracellular lectin-binding, olfactomedin-like, and mucin-like domains; said polypeptide comprising the amino acid sequence set out in SEQ ED NO: 80 or fragment thereof. 3. A polynucleotide encoding the polypeptide according to any one of claims 1 and 2. 4. The polynucleotide according to claim 3 comprising the sequence set forth in SEQ ED NO: 69. 5. The polynucleotide according to claim 3 comprising the sequence set forth in SEQ ED NO: 79. 6. A polynucleotide encoding a human lectomedin polypeptide selected from the group consisting of: a) the polynucleotide set out in SEQ ED NO: 69 or 79; b) a DNA which hybridizes under moderately stringent conditions to the non-coding strand ofthe polynucleotide of (a); and c) a DNA which would hybridize to the non-coding strand of the polynucleotide of (a) but for the redundancy ofthe genetic code. 7. A polynucleotide encoding a human lectomedin polypeptide selected from the group consisting of: a) the polynucleotide set out in SEQ ED NO: 1, 3, 5, 69, or 79; b) a polynucleotide encoding the polypeptide set out in SEQ ED NO: 2, 4, 6, 70, or 80; and c) a polynucleotide that hybridizes to the polynucleotide of (a) or (b) under moderately stringent conditions. 8. The polynucleotide of claim 6 or 7 which is a DNA molecule. 9. The DNA of claim 8 which is a cDNA molecule. 10. The DNA of claim 8 which is a wholly or partially chemically synthesized DNA molecule. 11. An anti-sense polynucleotide which specifically hybridizes with the polynucleotide of claim 8. 12. A expression constmct comprising the polynucleotide according to claim 6 or 7. 13. A host cell transformed or transfected with the polynucleotide according to claim 6 or 7. 14. The polynucleotide according to claim 6 or 7 operably linked to a heterologous promoter. 15. A host cell comprising the polynucleotide according to claim 14. 16. A method for producing a human lectomedin polypeptide comprising the steps of: a) growing the host cell according to claim 13 under conditions appropriate for expression ofthe lectomedin polypeptide and b) isolating the lectomedin polypeptide from the host cell or the medium of its growth. 17. An antibody specifically immunoreactive with the polypeptide according to any one of claims 1 and 2. 18. The antibody according to claim 17 which is a monoclonal antibody. 19. A hybridoma which produces the antibody according to claim 18. 20. An anti-idiotype antibody specifically immunoreactive with the antibody according to claim 18. 21. A method to identify a specific binding partner compound ofthe lectomedin polypeptide according to any one of claims 1 and 2 comprising the steps of: a) contacting the lectomedin polypeptide with a compound under conditions which permit binding between the compound and the lectomedin polypeptide; b) detecting binding ofthe compound to the lectomedin polypeptide; and c) identifying the compound as a specific binding partner ofthe lectomedin polypeptide. 22. The method according to claim 21 wherein the specific binding partner modulates activity ofthe lectomedin polypeptide. 23. The method according to claim 22 wherein the compound inhibits activity ofthe lectomedin polypeptide. 24. The method according to claim 22 wherein the compound enhances activity ofthe lectomedin polypeptide. 25. A method to identify a specific binding partner compound ofthe lectomedin polynucleotide according to claim 6 or 7 comprising the steps of: a) contacting the lectomedin polynucleotide with a compound under conditions which permit binding between the compound and the lectomedin polynucleotide; b) detecting binding ofthe compound to the lectomedin polynucleotide; and c) identifying the compound as a specific binding partner ofthe lectomedin polynucleotide. 26. The method according to claim 25 wherein the specific binding partner modulates expression of a lectomedin polypeptide encoded by the lectomedin polynucleotide. 27. The method according to claim 26 wherein the compound inhibits expression ofthe lectomedin polypeptide. 28. The method according to claim 26 wherein the compound enhances expression ofthe lectomedin polypeptide. 29. A compound identified by the method according to claim 21 or 26. 30. A composition comprising the compound according to claim 29 and a pharmaceutically acceptable carrier. 31. A method for identifying a modulator of lectomedin binding to a binding partner comprising the steps of: a) measuring binding between lectomedin and the binding partner in the presence and absence of a test compound; and b) identifying the test compound as a modulator of lectomedin binding to the binding partner binding when a different level of lectomedin binding to the binding partner is detected in the presence ofthe test compound compared to lectomedin binding the binding partner in the absence ofthe test compound. 32. The method according to claim 31 wherein the binding partner is selected from the group consisting of galectin-3 (Mac-2); fibrinogen; immunoglobulin mu chain constant region; KIAA0445; hepatitis Delta antigen-interacting protein dip A; kinesin-related protein, KEF3C; G0/G1 regulatory switch protein G0S3 (FOSB); neuron-specific amyloid protein homologous to AMY; RANBPM; AD A3 -like protein that is part ofthe PCAF histone acetylase complex; and human genomic clone ® 18_A_13 (GenBank Accession No: AC007198) 33. A method for modulating lectomedin binding to a binding partner comprising the step of contacting lectomedin or the binding partner with a modulator of lectomedin binding to the binding partner. 34. The method according to claim 33 wherein the binding partner is selected from the group consisting of galectin-3 (Mac-2); fibrinogen; immunoglobulin mu chain constant region; KLAA0445; hepatitis Delta antigen-interacting protein dip A; kinesin-related protein, KEF3C; G0/G1 regulatory switch protein G0S3 (FOSB); neuron-specific amyloid protein homologous to AMY; RANBPM; AD A3 -like protein that is part ofthe PCAF histone acetylase complex; and human genomic clone 18_A_13 (GenBank® Accession No: AC007198) 35. The method according to claim 33 wherein the modulator is an inhibitor. 36. The method according to claim 33 wherein the modulator is an enhancer. 37. A method to ameliorate a disease state associated with lectomedin binding to a binding partner comprising the step of administering to an individual in need thereof an effective amount of a modulator of lectomedin binding to the binding partner. 38. The method according to claim 37 wherein the binding partner is selected from the group consisting of galectin-3 (Mac-2); fibrinogen; immunoglobulin mu chain constant region; KIAA0445; hepatitis Delta antigen-interacting protein dipA; kinesin-related protein, KEF3C; G0/G1 regulatory switch protein G0S3 (FOSB); neuron-specific amyloid protein homologous to AMY; RANBPM; AD A3 -like protein that is part ofthe PCAF histone acetylase complex; and human genomic clone ® 18_A_13 (GenBank Accession No: AC007198) 39. The method according to claim 37 wherein the modulator inhibits binding between lectomedin and the binding partner. 40. The method according to claim 37 wherein the modulator enhances binding between lectomedin and the binding partner. 41. The method according to claim 37 wherein the binding partner is galectin-3. 42. The method according to claim 41 wherein the disease state is selected from the group consisting of atherosclerosis, restenosis or vascular disease.

Inventors: DOUANGPANYA JASON, FOX RAYMOND D, HAYFLICK JOEL S, PURI KAMAL D, DOUANGPANYA, JASON, FOX, RAYMOND, D., HAYFLICK, JOEL, S., PURI, KAMAL, D.
Applicants: ICOS CORP, ICOS CORPORATION
Application year: 2000
Main classification: C07K14
IPC codes: A61K38, C07K14