WSX RECEPTOR AND LIGANDS

Abstract: The WSX receptor and antibodies which bind thereto (including agonist and neutralizing antibodies) are disclosed, including various uses therefor. Uses for WSX ligands (e.g., anti-WSX receptor agonist antibodies or OB protein) in hematopoiesis are also disclosed.

Description: WSX RECEPTOR AND LIGANDS CROSS REFERENCES This application is a continuation-in-part of co-pending U.S. Application Serial No. 08/667,197 filed June 20, 1996, which is a continuation-in-part of co-pending U.S. Application Serial No. 08/585,005 filed January 8, 1996, which applications are incoφorated herein by reference and to which applications priority is claimed under 35 USC §120. BACKGROUND OF THE INVENTION Field of the Invention The present invention pertains generally to the WSX receptor and ligands and uses for these molecules. Description of Related Art A. HEMATOPOIESIS The process of blood cell formation whereby red and white blood cells are replaced through the division of cells located in the bone marrow is called hematopoiesis. For a review of hematopoiesis see Dexter and Spooncer (Arm. Rev. Cell Biol. 3:423-441 (1987)). There are many different types of blood cells which belong to distinct cell lineages. Along each lineage, there are cells at different stages of maturation. Mature blood cells are specialized for different functions. For example, erythrocytes are involved in C>2 and CC>2 transport; T and B lymphocytes are involved in cell and antibody mediated immune responses, respectively; platelets are required for blood clotting; and the granulocytes and macrophages act as general scavengers and accessory cells. Granulocytes can be further divided into basophils, eosinophils, neutrophils and mast cells. Each ofthe various blood cell types arises from pluripotent or totipotent stem cells which are able to undergo self-renewal or give rise to progenitor cells or Colony Forming Units (CFU) that yield a more limited array of cell types. As stem cells progressively lose their ability to self-renew, they become increasingly lineage restricted. It has been shown that stem cells can develop into ultipotent cells (called "CFC-Mix" by Dexter and Spooncer, supra). Some of the CFC-Mix cells can undergo renewal whereas others lead to lineage-restricted progenitors which eventually develop into mature myeloid cells (e.g., neutrophils, megakaryocytes, macrophages and basophils). Similarly, pluripotent stem cells are able to give rise to PreB and PreT lymphoid cell lineages which differentiate into mature B and T lymphocytes, respectively. Progenitors are defined by their progeny, e.g. , granulocyte/macrophage colony-forming progenitor cells (GM-CFU) differentiate into neutrophils or macrophages; primitive erythroid burst-forming units (BFU-E) differentiate into erythroid colony-forming units (CFU-E) which give rise to mature erythrocytes. Similarly, the Meg-CFU, Eos-CFU and Bas-CFU progenitors are able to differentiate into megakaryocytes, eosinophils and basophils, respectively. Hematopoietic growth factors (reviewed in Andrea, Λ£/Λ 330(12):839-846 (1994)) have been shown to enhance growth and/or differentiation of blood cells via activation of receptors present on the surface of blood progenitor cells ofthe bone marrow. While some of these growth factors stimulate proliferation of restricted lineages of blood cells, others enhance proliferation of multiple lineages of blood cells. For example, erythropoietin (EPO) supports the proliferation of erythroid cells, whereas interleukin-3 (1L-3) induces proliferation of erythroid and myeloid lineages and is therefore considered a multi-lineage factor. In recent years, several hematopoietic growth factor receptors have been isolated Due to their low abundance and their existence in both high-affinity and low-affinity forms, biochemical characterization of these receptors has been hampered Cytokine receptors frequently assemble into multi-subumt complexes Sometimes, the cc subunit of this complex is involved in binding the cognate growth factor and the β-subunit may contain an ability to transduce a signal to the cell These receptors have been assigned to three subfamilies depending on the complexes formed Subfamily 1 includes the receptors for erythropoietin (EPO), granulocyte colony-stimulating factor (G-CSF), ιnterleukιn-4 (IL-4), ιnterleukιn-7 (IL-7), growth hormone (GH) and prolactm (PRL) Ligand binding to receptors belonging to this subfamily is thought to result in homodimeπzation of the receptor Subfamily 2 includes receptors for IL-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), ιnterleukιn-5 (IL-5) ιnterleukιn-6 (IL-6), leukemia inhibitory factor (LIF), oncostatin M (OSM) and ciliary neurotrophic factor (CNTF) Subfamily 2 receptors are heterodimers having an oc -subunit for ligand binding and β-subunit (either the shared β-subunit ofthe IL-3, GM-CSF and IL-5 receptors or the gpl 30 subunit of the IL-6, LIF, OSM and CNTF receptors) for signal transduction Subfamily 3 contains only the ιnterleukιn-2 (IL-2) receptor The β and γ subunits ofthe IL-2 receptor complex are cytokine-receptor polypeptides which associate with the α- subunit ofthe unrelated Tac antigen B OBESITY Obesity is the most common nutritional disorder which, according to recent epidemiologic studies, affects about one third of all Americans 20 years of age or older Kuczmarski et al , J Am Med Assoc 272 205- 1 1 (1994) Obesity is responsible for a variety of serious health problems, including cardiovascular disorders, type II diabetes, insulin-resistance, hypertension, hypertπglyceπdemia, dyslipoproteinemia, and some forms of cancer Pi-Sunyer, F , Anns Int Med 1 19 655-60 (1993), Colfitz, G , Am J Clm Nutr 55 503S-507S (1992) A single-gene mutation (the obesity or "ob" mutation) has been shown to result in obesity and type II diabetes in mice Friedman, Genomtcs 1 1 1054-1062 (1991) Zhang et al , Nature 372 425-431 (1994) have recently reported the cloning and sequencing of the mouse ob gene and its human homologue, and suggested that the ob gene product, leptin or OB protein, may function as part ofa signalling pathway from adipose tissue that acts to regulate the size ofthe body fat depot Parabiosis expenments performed more than 20 years ago predicted that the genetically obese mouse containing two mutant copies ofthe ob gene (ob/ob mouse) does not produce a satiety factor which regulates its food intake, while the diabetic (db/db) mouse produces but does not respond to a satiety factor Coleman and Hummal, Am J Physiol 217 1298-1304 (1969), Coleman, Dtabetol 9 294-98 (1973) Recent reports by three independent research teams have demonstrated that daily injections of recombinant OB protein inhibit food intake and reduce body weight and fat in grossly obese ob/ob mice but not in db/db mice (Pelleymounter et al Science 269 540-43 (1995), Halaas et al , Science 269 543-46 (1995), Campfield et al , Science 269 546-49 (1995)), suggesting that the OB protein is such a satiety factor as proposed in early cross-circulation studies Researchers suggest that at least one OB receptor is localized in the brain The identification and expression cloning of a leptin receptor (OB-R) was reported by Tartaglia et al Cell 83 1263-71 ( 1995) Various isoforms of a OB receptor are described by Cioffi et al Nature 2 585-89 ( 1996) See, also, WO 96/08510 The mouse db gene has recently been cloned (Lee et al. Nature 379:632 (1996) and Chen et al Cell 84:491-495 (1996)). Previous data had suggested mat the db gene encoded the receptor for the obese (ob) gene product, leptin (Coleman et al. , Diebetologia 9:294-8 (1973) and Coleman et al. , Diebetologia 14 : 141 -8 ( 1978 )) . It has been very recently confirmed that the db/db mouse results from a truncated splice variant of the OB receptor which likely renders the receptor defective in signal transduction (Lee et al, Nature 379:632 (1996) and Chen et al, Cell 84: 491-495 (1996)). SUMMARY OF THE INVENTION The invention herein is concerned with the WSX cytokine receptor and a soluble form of the receptor which is the WSX receptor extracellular domain (ECD). The WSX receptor polypeptides are optionally conjugated with, or fused to, molecules which increase the serum half-lives thereof and can be formulated as pharmaceutical compositions comprising the polypeptide and a physiologically acceptable carrier. In certain embodiments, the WSX receptor ECD may be used as an antagonist insofar as it may bind to WSX ligand and thereby reduce activation of endogenous WSX receptor. This may be useful in conditions characterized by excess levels of WSX ligand and or excess WSX receptor activation in a mammal. WSX receptor ECD may, for example, be used to treat metabolic disorders (e.g., anorexia or steroid-induced truncalobesity), stem cell tumors and other tumors which express WSX receptor. Pharmaceutical compositions ofthe WSX receptor ECD may further include a WSX ligand. Such dual compositions may be beneficial where it is therapeutically useful to prolong the half-life of WSX ligand and/or activate endogenous WSX receptor directly as a heterotrimeric complex. The invention also relates to chimeric WSX receptor molecules, such as WSX receptor immunoadhesins (having long half-lives in the serum of a patient treated therewith) and epitope tagged WSX receptor. Immunoadhesins may be employed as WSX receptor antagonists in conditions or disorders in which neutralization of WSX receptor biological activity may be beneficial. Bispecific immunoadhesins (combining a WSX receptor ECD with a domain of another cytokine receptor) may form high affinity binding complexes for WSX ligand. The invention further provides methods for identifying a molecule which binds to and/or activates the WSX receptor. This is useful for discovering molecules (such as peptides, antibodies, and small molecules) which are agonists or antagonists of the WSX receptor. Such methods generally involve exposing an immobilized WSX receptor to a molecule suspected of binding thereto and determining binding of the molecule to the immobilized WSX receptor and/or evaluating whether or not the molecule activates (or blocks activation of) the WSX receptor. In order to identify such WSX ligands, the WSX receptor may be expressed on the surface of a cell and used to screen libraries of synthetic compounds and naturally occurring compounds (e.g., endogenous sources of such naturally occurring compounds, such as serum). The WSX receptor can also be used as a diagnostic tool for measuring serum levels of endogenous WSX ligand. In a further embodiment, a method for purifying a molecule which binds to the WSX receptor is provided. This can be used in the commercial production and purification of therapeutically active molecules which bind to this receptor. In the method, the molecule of interest (generally a composition comprising one or more contaminants) is adsorbed to immobilized WSX receptor (e.g., WSX receptor immunoadhesin immobilized on a protein A column). The contaminants, by virtue of their inability to bind to the WSX receptor, will generally flow through the column. Accordingly, it is then possible to recover the molecule of interest from the column by changing the elution conditions, such that the molecule no longer binds to the immobilized receptor. In further embodiments, the invention provides antibodies that specifically bind to the WSX receptor. Preferred antibodies are monoclonal antibodies which are non-immunogenic in a human and bind to an epitope in the extracellular domain of the receptor. Preferred antibodies bind the WSX receptor with an affinity of at least about 10 L/mole, more preferably 10 L/mole. Antibodies which bind to the WSX receptor may optionally be fused to a heterologous polypeptide and the antibody or fusion thereof may be used to isolate and purify WSX receptor from a source ofthe receptor. In a further aspect, the invention provides a method for detecting the WSX receptor in vitro or in vivo comprising contacting the antibody with a sample suspected of containing the receptor and detecting if binding has occurred. Based on the observation herein that CD34+ cells possess WSX receptor, use of WSX antibodies for identification and/or enrichment of stem cell populations (in a similar manner to that in which CD34 antibodies are presently used) is envisaged. For certain applications, it is desirable to have an agonist antibody which can be screened for as described herein. Such agonist antibodies are useful for activating the WSX receptor for in vitro uses whereby enhancement of proliferation and/or differentiation of a cell comprising the receptor is desired. Furthermore, these antibodies may be used to treat conditions in which an effective amount of WSX receptor activation leads to a therapeutic benefit in the mammal treated therewith. For example, the agonist antibody can be used to enhance survival, proliferation and/or differentiation ofa cell comprising the WSX receptor. In particular, agonist antibodies and other WSX ligands may be used to stimulate proliferation of stem cells/progenitor cells either in vitro or in vivo. Other potential therapeutic applications include the use of agonist antibodies to treat metabolic disorders (such as obesity and diabetes) and to promote kidney, Iiver or lung growth and/or repair (e.g., in renal failure). For therapeutic applications it is desirable to prepare a composition comprising the agonist antibody and a physiologically acceptable carrier. Optionally, such a composition may further comprise one or more cytokines. In other embodiments, the antibody is a neutralizing antibody. Such molecules can be used to treat conditions characterized by unwanted or excessive activation ofthe WSX receptor. In addition to the above, the invention provides isolated nucleic acid molecules, expression vectors and host cells encoding the WSX receptor which can be used in the recombinant production of WSX receptor as described herein. The isolated nucleic acid molecules and vectors are also useful for gene therapy applications to treat patients with WSX receptor defects and/or to increase responsiveness of cells to WSX ligand. This application also relates to agonist antibodies which specifically bind to the WSX receptor and mimic one or more biological activities of naturally occurring WSX ligand, OB protein. Preferred antibodies are those with a strong binding affinity for human WSX receptor (e.g. having a Kd of no more than about 1 x 10° \1 ; and preferably no more than about 1 x 10 M). In preferred embodiments, the agonist antibody binds to both human and murine WSX receptor. Antibodies with defined agonistic activity in a bioassay, the KIRA ELISA, are disclosed herein. Preferred antibodies have an IC50 in the KIRA ELISA of about 0.5μg/ml or less, preferably about 0.2μg/ml or less, and most preferably about 0.1 μg/ml or less. The agonist antibodies of interest herein may have one or more of the biological characteristics of antibody 2D7, 1G4, 1E1 1 or 1C1 1 (see Example 13) or clones 3, 4, or 17 (see Example 14). For example, the antibody may bind to the epitope bound by any one of these antibodies, and/or may have some or all of the hypervariable region residues of these antibodies. The agonist antibody may be one which decreases body weight and/or fat-depot weight and/or food intake in an obese mammal (e.g. in an oblob mouse). The preferred agonist antibody is one which exerts an adipose-reducing effect in an obese mammal (e.g. an oblob mouse) which is in excess of that induced by a reduction in food intake (Levin et al. Proc. Natl. Acad. Sci. USA 93: 1726-1730 ( 1996)). The agonist antibody may also have the property of inducing differentiation and or proliferation and/or survival of hematopoietic progenitor cells. For example, the agonist antibody may induce lymphopoiesis, erythropoiesis and/or myelopoiesis. The invention further provides a composition comprising the agonist antibody and a physiologically acceptable carrier. The composition for therapeutic use is sterile and may be lyophilized. For use in hematopoiesis, for example, the composition may further comprise a cytokine. In another aspect, the invention provides a method for activating the WSX receptor which comprises exposing the WSX receptor to an amount of an agonist anti-WSX receptor antibody which is effective for activating the WSX receptor. The invention further provides a method for enhancing proliferation and/or differentiation ofa cell which expresses the WSX receptor at its cell surface comprising exposing the cell to an amount of exogenous agonist anti-WSX receptor antibody which is effective for enhancing proliferation and/or differentiation ofthe cell. In another embodiment, the invention provides a method for decreasing body weight and/or fat-depot weight and/or food intake in an obese mammal (e.g. a human) comprising administering an effective amount ofthe agonist antibody to the mammal. Also, the invention provides a method for treating the medical sequelae of obesity in a mammal, such as, e.g., arteriosclerosis, Type II diabetes, polycystic ovarian disease, cardiovascular diseases, osteoarthritis, dermatological disorders, hypertension, insulin resistance, hypercholesterolemia, hypertriglyceridemia, cancer and cholelithiasis, comprising administering an effective amount of an agonist anti-WSX receptor antibody to the mammal. The mammal to be treated may be one diagnosed with any one or more of these diseases, or may be predisposed to these diseases. In another aspect, the present invention pertains to the discovery herein that WSX ligands, such as obesity (OB) protein, play a role in hematopoiesis via signalling through the WSX receptor. The role ofthe WSX receptor-ligand signalling pathway appears to be at the level ofthe early hematopoietic precursor as is evident by the ability of OB protein to simulate myelopoiesis, erythropoiesis (e.g. splenic erythropoiesis) and most dramatically, lymphopoiesis. Accordingly, WSX ligands can be used to stimulate proliferation and/or differentiation and/or survival of hematopoietic progenitor cells either in vitro or in vivo (e.g. for treating hematopoietic diseases or disorders). Thus, the invention provides a method for stimulating proliferation and/or differentiation ofa cell which expresses the WSX receptor (especially the WSX receptor variant 13.2, which is demonstrated herein to have the capacity to transmit a proliferative signal) at its cell surface comprising the step of contacting the WSX receptor with an amount of WSX ligand which is effective for stimulating proliferation and/or OB protein differentiation of the cell In prefered embodiments, the cell which is exposed to the WSX ligand is a hematopoeitic precursor, e g a CD34+ cell The WSX ligand may be OB protein or an agonist antibody which binds to the WSX receptor For in vivo use, the WSX ligand of choice may be a long half-life derivative of an OB protein, such as OB-immunoglobulin chimera and/or OB protein modified with a nonprotemaceous polymer such as polyethylene glycol (PEG) The method contemplated herein may lead to an increase in the proliferation and/or differentiation of lymphoid, myeloid and/or erythroid blood cell lineages and encompasses both in vitro and in vivo methods For in vitro uses, the cell possessing the WSX receptor may be present in cell culture As to in vivo methods, the cell may be present in a mammal, especially a human (e g one who is suffering from decreased blood levels and who could benefit from an increase in various blood cells) Potential patients include those who have undergone chemo- or radiation therapy, or bone marrow transplantation therapy Thus, the invention provides a method for repopulating blood cells (e g erythroid, myeloid and or lymphoid blood cells) in a mammal comprising administering to the mammal a therapeutically effective amount of a WSX ligand Mammals which may benefit from an enhancement of lymphopoiesis include those predisposed to, or suffering from, any ony or more of the following exemplary conditions lymphocytopenia, lymphorrhea, lymphostasis, immunodeficiency (e g HIV and AIDS), infections (including, for example, opportunistic infections and tuberculosis (TB)), lupus, and other disorders characterized by lymphocyte deficiency An effective amount ofthe WSX ligand can be used in a method of immunopotentiation or to improve immune function in a mammal On the other hand, WSX receptor or WSX ligand antagonists (such as WSX receptor ECD or lmmunoadhesin, and WSX receptor or OB protein neutralizing antibodies) may be used in the treatment of those disorders wherein unacceptable lymphocyte levels are present m the mammal, particularly where this is caused by excessive activation of the WSX receptor Examples of conditions in which administration of such an antagonist may be beneficial include neoplastic disorders (such as Hodkm's disease, lymphosarcoma, lymphoblastoma, lymphocytic leukemia, and lymphoma) and lymphocytosis Diseases or disorders in which an increase in erythropoiesis may be beneficial include, but are not limited to erythrocytopenia, erthrodegenerative disorders, erythroblastopenia, leukoerythroblastosis, erythroclasis, thalassemia, and anemia (e g hemolytic anemia, such as acquired, autoimmune, or microangiopathic hemolytic anemia, aplastic anemia, congenital anemia, e g , congenital dyserythropoietic anemia, congenital hemolytic anemia or congenital hypoplastic anemia, dyshemopoietic anemia, Faconi's anemia, genetic anemia, hemorrhagic anemia, hyperchromic or hypochromic anemia, nutritional, hypoferπc, or iron deficiency anemia, hypoplastic anemia, infectious anemia, lead anemia, local anemia, macrocytic or microcytic anemia, malignant or pernicious anemia, megaloblastic anemia, molecular anemia, normocytic anemia, physiologic anemia, traumatic or posthemorrhagic anemia, refractory anemia, radiation anemia, sickle cell anemia, splenic anemia; and toxic anemia) Conversely, WSX receptor or WSX ligand antagonists may be used to treat those conditions in which excessive erythrocyte levels are present in a mammal, e g in neoplastic disorders such as erythroleukemia, erythroblastosis, and erythrocythemia or polycythemia An increase in myelopoiesis may be beneficial in any ofthe above-mentioned diseases or disorders as well as the following exemplary conditions: myelofϊbrosis; thrombocytopenia; hypoplasia; disseminated intravascular coagulation (DIC); immune (autoimmune) thrombocytopenic purpura (ITP); HIV induced ITP; myelodysplasia; thrombocytotic diseases and thrombocytosis. Antagonists ofthe WSX receptor- WSX ligand interaction may also be used to treat myeloid cell-related conditions such as malignancies (e.g. myelosarcoma, myeloblastoma, myeloma, myeloleukemia and myelocytomatosis); myeloblastosis; myelocytosis; and myelosis. The method may further involve the step of exposing hematopoeitic cells (whether they be in cell culture or in a mammal) to one or more other cytokines (e.g. lineage-specific cytokines) and this may lead to a synergistic enhancement ofthe proliferation and/or differentiation ofthe cells. Exemplary cytokines include thrombopoietin (TPO); erythropoietin (EPO); macrophage-colony stimulating factor (M-CSF); granulocyte- acrophage-CSF (GM-CSF); granulocyte-CSF (G-CSF); interleukin-l (IL-l); IL-l α; IL-2; IL-3; IL-4; IL-5; IL- 6; IL-7; IL-8; IL-9; IL-l 1 ; IL10; IL-l 2; leukemia inhibitory factor (LIF) or kit ligand (KL). In this embodiment, exposure to the cytokine may proceed, occur simultaneously with, or follow, exposure to the WSX ligand. Preferably, the WSX ligand and one or more further cytokines are administered simultaneously to the patient (where the method is an in vivo one) and, optionally, are combined to form a pharmaceutical composition For use in the above methods, the invention also provides an article of manufacture, comprising: a container; a label on the container; and a composition comprising an active agent within the container; wherein the composition is effective for enhancing proliferation and/or differentiation of cells comprising the WSX receptor in a mammal, the label on the container indicates that the composition can be used for enhancing proliferation and or differentiation of those cells and the active agent in the composition is a WSX ligand. Optionally, the article of manufacture includes one or more futher containers which hold further cytokine(s) in a packaged combination with the container holding die WSX ligand. In another embodiment, an effective amount ofthe WSX ligand may be used to improve engraftment in bone marrow transplantation or to stimulate mobilization of hematopoietic stem cells in a mammal prior to harvesting hematopoietic progenitors from the peripheral blood thereof. BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1A-H together depict the double stranded nucleotide (SEQ ID NO: 1 ) and deduced amino acid sequence (SEQ ID NO:2) encoding full length human WSX receptor variant 13.2. Nucleotides are numbered at the beginning of the sense strand. Amino acid residues are numbered at the beginning of the amino acid sequence. Restriction enzyme sites are depicted above the nucleotide sequence. Figs. 2A-B together depict an amino acid sequence alignment of full length human WSX receptor variants 6.4 (SEQ ID NO:3), 12.1 (SEQ ID NO:4) and 13.2, respectively. Homologous residues are boxed. WSX receptor variants 6.4, 12.1 and 13.2 are native sequence human WSX receptor variants which, without being bound to any one theory, appear to be generated by alternate splicing of WSX receptor mRNA. The putative signal peptide, transmembrane, Box 1, Box 2, and Box 3 domains are indicated. The extracellular and cytoplasmic domains are amino- and carboxy-terminal, respectively, to the transmembrane domain. The Box 1-3 domains shown correspond to the box 1-3 motifs described in Baumann / α/., Mol. Cell. Biol. 14(1): 138- 146 (1994). Figs. 3A-E together depict an alignment of the nucleotide sequences encoding human WSX receptor variants 6.4 (SEQ ID NO:5), 12.1 (SEQ ID NO:6) and 13.2, respectively. Figs. 4A-B depict an alignment of the full length human WSX receptor variant 13.2 amino acid sequence (top) with that of partial murine WSX receptor extracellular domain sequence (bottom) (SEQ ID NO:7) obtained as described in Example 7. The putative murine signal peptide is marked with an arrow. Figs. 5A-F represent an alignment ofthe nucleotide sequences encoding human WSX receptor variant 13.2 (bottom) and partial murine WSX receptor extracellular domain (top) (SEQ ID NO:8), respectively. Fig. 6 is a bar graph depicting results ofthe thymidine incoφoration assay described in Example 5. ^H- thymidine incoφoration (counts per minute, CPM) in parental BaO cells or BaO cells electroporated with GH/WSX variant 13.2 chimera in the presence of varying concentrations of human growth hormone (GH) is shown. Fig. 7 shows the human and murine oligonucleotides (SEQ ID NOS:9-38, respectively) used for the antisense experiment described in Example 8. Figs. 8 and 9 show thymidine incoφoration assays in Baf-3 cells. For these assays, cells were deprived of IL-3 for 16-18 hours (in RPMI 1640 supplemented with 10% fetal calf serum (FCS)). Cells were washed in serum free RPMI 1640 and plated at 50,000 cells per well in 0.2 mis of serum free RPM! 1640 supplemented with the indicated concentration of human GH or human OB protein. Cells were stimulated for 24 hours and thymidine incoφoration was determined as described (Zeigler et al. Blood 84:2422-2430 (1994)). Assays were performed in triplicate and the results were confirmed in three independent experiments. In Fig. 8, GH receptor- WSX receptor variant 12.1 or 13.2 chimeric proteins were expressed in Baf-3 cells as described in Example 5. These transfected cells and the parental Baf-3 line were stimulated with hGH and the incoφoration of titrated thymidine determined. In Fig. 9, Baf-3 cells were stably transfected with WSX receptor variant 13.2. Thymidine incoφoration was then determined in these cell lines following stimulation with human OB protein. In Figs. 10A-C, murine fetal liver AA4 + Sca + Kit + (flASK) stem cells were cultured in suspension culture or methylcellulose. In Fig. 10A, flASK cells were cultured in suspension culture containing serum with kit ligand (KL) or kit ligand and OB protein. Cell counts and cytospin analyses were performed 7 days later. In Fig. 10B, flASK cells were seeded into methylcellulose under either myeloid or lymphoid conditions as described in Example 10. Colony counts were performed 14 days later. For colonies produced under lymphoid conditions, FACS analysis demonstrated the vast majority of cells to be B220 positive. In Fig. 10C, flASK cells were seeded into methylcellulose containing kit ligand. To this base media, erythropoietin (EPO) or erythropoietin and OB protein were then added. The resultant colonies were counted 14 days later. FACS analysis demonstrated approximately 95% of these colonies to be TER 119 positive. All assays were performed in triplicate and confirmed in at least three independent experiments. Fig. 11 illustrates methylcellulose assays to determine the colony forming potential of db/db, ob/ob and the corresponding wild-type marrow. 100,000 bone marrow cells were seeded into methylcellulose and the resultant colonies counted after 14 days. Assays were performed using both myeloid and lymphoid conditions. Assays were performed in triplicate and the experiments were repeated a minimum of 3 times. Figs. 12A-B show bone marrow cellular profiles in wild-type misty gray homozygotes, misty gray /db heterozygotes, and homozygote db/db mice. Overall cellularity in the db/db marrow was unchanged compared to controls. Fig. 12A shows cellular profiles determined using anti-B220, anti-CD43, and anti-TER1 19 antibodies. Fig. 12B shows cellular profiles ofthe spleens from the above groups. Figs. 13A-C are an analysis of peripheral blood in db/db homozygotes, db/db misty gray heterozygotes and misty gray homozygotes. 40 microliters of peripheral blood was taken via orbital bleed and analyzed on a Serrono Baker system 9018. All areas described by the boxes represent the mean ± one standard deviation of the two parameters. Fig. 14 is a comparison of peripheral lymphocyte counts and blood glucose level. Five groups of animals, misty-gray, misty-gray >, db/db, interferon α-transgenic, and glucokinase transgenic heterozygote mice (gLKa) were sampled via retro-orbital bleed. Blood glucose levels in these mice were determined. All areas described by the boxes represent the mean ± standard deviation of the two parameters. In Figs. 15A-C, misty gray homozygotes, dblmisty gray heterozygotes, and homozygous db/db mice were subjected to sub-lethal irradiation and the recovery kinetics ofthe peripheral blood was determined via retro-orbital bleeds. Figs. 16A-16Q together show the nucleotide sequence (SEQ ID NO:46) and the amino acid sequence (SEQ ID NO: 47) ofthe human OB-immunoglobulin chimera in the plasmid described in of Example 1 1. Fig. 17 shows binding of anti- WSX receptor agonist antibodies to human WSX receptor. The anti-WSX receptor agonist antibodies (2D7 and I G4) produced as described in Example 13 and an IgG isotope control were evaluated for their ability to bind to human WSX receptor by capture ELISA. Fig. 18 shows the activity of mAbs 2D7 and 1 G4 as well as OB protein in the KIRA ELISA (see Example 13). Absorbance at 490nm versus concentration of antibody or ligand in this assay is shown. Fig. 19 depicts binding of anti-WSX receptor agonist antibodies to murine WSX receptor. The anti- WSX receptor agonist antibodies (2D7 and 1G4) and an IgG isotope control were evaluated for their ability to bind to murine WSX receptor by capture ELISA. Figs.20A-B show the results of epitope mapping ofthe agonist anti-WSX receptor antibodies produced as described in Example 13. Fig. 20A shows blocking ability of anti-WSX receptor antibodies on Epitope A using biotinylated 2D7. Fig. 20B shows blocking ability of anti-WSX receptor antibodies on Epitope B using biotinylated 1 C 1 1. Based on the competitive binding ELISA, 2D7 bound a different epitope from 1 E 1 1 , 1 C 1 1 and 1G4. Fig. 21 depicts an alignment ofthe amino acid sequences of full length human WSX receptor variant 6.4 (hWSXR) (SEQ ID NO:3) and murine WSX receptor (mWSXR) (SEQ ID NO:51 ). Fig. 22 is a standard curve for human OB protein in the KIRA ELISA, which illustrates schematically inside the graph WSX receptor KIRA ELISA panning with scFv phage as described in Example 14. Fig. 23 shows the activity of clone # 3, #4 and # 17 scFv phage from Example 14 and anti-HER2 scFv phage control in the KIRA ELISA. Absorbance versus phage titer is shown. Fig. 24 shows the activity of clone # 3, #4 and # 17 scFv from Example 14, anti-HER2 scFv control (Her2 clone) and OB protein in the KIRA ELISA. Absorbance versus antibody concentration is shown. Fig. 25 aligns the amino acid sequences of agonist antibody clone #3 (3.scFv) (SEQ ID NO:48), clone #4 (4.scFv) (SEQ ID NO:49) and clone #17 (17.scFv) (SEQ ID NO:50) obtained as described in Example 14. Complementarity determining region (CDR) residues according to Kabat et al, Sequences of Proteins of Immunological Interest. 5th Ed. Public Health Service, National Institutes of Health, Bethesda, MD. (1991 ) are underlined and hypervariable loop residues (Chothia et al., Nature 342:8767 ( 1989)) are in italics. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS I. Definitions In describing the present invention, the following terms will be employed, and are intended to be defined as indicated below. The terms "WSX receptor" or "WSX receptor polypeptide" when used herein encompass native sequence WSX receptor; WSX receptor variants; WSX extracellular domain; and chimeric WSX receptor (each of which is defined herein). Optionally, the WSX receptor is not associated with native glycosylation. "Native glycosylation" refers to the carbohydrate moieties which are covalently attached to WSX receptor when it is produced in the mammalian cell from which it is derived in nature. Accordingly, human WSX receptor produced in a non-human cell is an example of a WSX receptor which is "not associated with native glycosylation". Sometimes, the WSX receptor is unglycosylated (e.g., as a result of being produced recombinantly in a prokaryote). "WSX ligand" is a molecule which binds to and activates native sequence WSX receptor (especially WSX receptor variant 13.2). The ability ofa molecule to bind to WSX receptor can be determined by the ability ofa putative WSX ligand to bind to WSX receptor immunoadhesin (see Example 2) coated on an assay plate, for example. The thymidine incoφoration assay provides a means for screening for WSX ligands which activate the WSX receptor. Exemplary WSX ligands include anti-WSX receptor agonist antibodies and OB protein (e.g., described in Zhang et al. Nature 372:425-431 (1994)). The terms "OB protein" and "OB" are used interchangeably herein and refer to native sequence OB proteins (also known as "leptins") and their functional derivatives. A "native sequence" polypeptide is one which has the same amino acid sequence as a polypeptide (e.g., WSX receptor or OB protein) derived from nature. Such native sequence polypeptides can be isolated from nature or can be produced by recombinant or synthetic means. Thus, a native sequence polypeptide can have die amino acid sequence of naturally occurring human polypeptide, murine polypeptide, or polypeptide from any other mammalian species. The term "native sequence WSX receptor" specifically encompasses naturally-occurring truncated forms ofthe WSX receptor, naturally-occurring variant forms (e.g., alternatively spliced forms such as human WSX receptor variants 6.4, 12.1 and 13.2 described herein) and naturally-occurring allelic variants of the WSX receptor. The preferred native sequence WSX receptor is a mature native sequence human WSX receptor, such as human WSX receptor variant 6.4, human WSX receptor variant 12.1 or human WSX receptor variant 13.2 (each shown in Figs. 2A-B). Most preferred is mature human WSX receptor variant 13.2. The term "native sequence OB protein" includes those OB proteins from any animal species (e.g. human, murine, rabbit, cat, cow, sheep, chicken, porcine, equine, etc.) as occurring in nature. The definition specifically includes variants with or without a giutamine at amino acid position 49, using the amino acid numbering of Zhang et al, supra. The term "native sequence OB protein" includes the native proteins with or without the initiating N-terminal methionine (Met), and with or without the native signal sequence, either in monomeric or in dimeric form. The native sequence human and murine OB proteins known in the art are 167 amino acids long, contain two conserved cysteines, and have the features of a secreted protein. The protein is largely hydrophilic, and the predicted signal sequence cleavage site is at position 21 , using the amino acid numbering of Zhang et al, supra. The overall sequence homology ofthe human and murine sequences is about 84%. The two proteins show a more extensive identity in the N-terminal region ofthe mature protein, with only four conservative and three non-conservative substitutions among the residues between the signal sequence cleavage site and the conserved Cys at position 1 17. The molecular weight of OB protein is about 16 kD in a monomeric form. The "WSX receptor extracellular domain" (ECD) is a form ofthe WSX receptor which is essentially free ofthe transmembrane and cytoplasmic domains of WSX receptor, i.e., has less than 1% of such domains, preferably 0.5 to 0% of such domains, and more preferably 0.1 to 0% of such domains. Ordinarily, the WSX receptor ECD will have an amino acid sequence having at least about 95% amino acid sequence identity with the amino acid sequence ofthe ECD of WSX receptor indicated in Figs.2A-B for human WSX receptor variants 6.4, 12.1 and 13.2, preferably at least about 98%, more preferably at least about 99% amino acid sequence identity, and thus includes WSX receptor variants as defined below. A "variant" polypeptide means a biologically active polypeptide as defined below having less than 100% sequence identity with a native sequence polypeptide (e.g., WSX receptor having the deduced amino acid sequence shown in Figs. 1A-H for human WSX receptor variant 13.2). Such variants include polypeptides wherein one or more amino acid residues are added at the N- or C-terminus of, or within, the native sequence; from about one to thirty amino acid residues are deleted, and optionally substituted by one or more amino acid residues; and derivatives ofthe above polypeptides, wherein an amino acid residue has been covalently modified so that the resulting product has a non-naturally occurring amino acid. Ordinarily, a biologically active WSX receptor variant will have an amino acid sequence having at least about 90% amino acid sequence identity with human WSX receptor variant 13.2 shown in Figs. 1 A-H, preferably at least about 95%, more preferably at least about 99%. Ordinarily, a biologically active OB protein variant will have an amino acid sequence having at least about 90% amino acid sequence identity with a native sequence OB protein, preferably at least about 95%, more preferably at least about 99%. A "chimeric" OB protein or WSX receptor is a polypeptide comprising OB protein or full-length WSX receptor or one or more domains thereof (e.g.,the extracellular domain ofthe WSX receptor) fused or bonded to heterologous polypeptide. The chimeric WSX receptor will generally share at least one biological property in common with human WSX receptor variant 13.2. The chimeric OB protein will generally share at least one biological property in common with a native sequence OB protein. Examples of chimeric polypeptides include immunoadhesins and epitope tagged polyeptides. The term "WSX immunoadhesin" is used interchangeably with the expression "WSX receptor- immunoglobulin chimera" and refers to a chimeric molecule that combines a portion of the WSX receptor (generally the extracellular domain thereof) with an immunoglobulin sequence. Likewise, an "OB protein immunoadhesin" or "OB-immunoglobulin chimera" refers to a chimeric molecule which combines OB protein (or a portion thereof) with an immunoglobulin sequence. The immunoglobulin sequence preferably, but not necessarily, is an immunoglobulin constant domain. The immunoglobulin moiety in the chimeras ofthe present invention may be obtained from IgGI, lgG2, lgG3 or IgG4 subtypes, IgA, IgE, IgD or IgM, but preferably IgGI or IgG3. The term "epitope tagged" when used herein refers to a chimeric polypeptide comprising WSX receptor or OB protein fused to a "tag polypeptide". The tag polypeptide has enough residues to provide an epitope against which an antibody thereagainst can be made, yet is short enough such that it does not interfere with biological activity ofthe WSX receptor or OB protein. The tag polypeptide preferably also is fairly unique so that the antibody thereagainst does not substantially cross-react with other epitopes. Suitable tag polypeptides generally have at least six amino acid residues and usually between about 8-50 amino acid residues (preferably between about 9-30 residues). "Isolated" WSX receptor (or OB protein) means WSX receptor (or OB protein) that has been purified from a WSX receptor (or OB protein) source or has been prepared by recombinant or synthetic methods and is sufficiently free of other peptides or proteins (1 ) to obtain at least 15 and preferably 20 amino acid residues of the N-terminal or of an internal amino acid sequence by using a spinning cup sequenator or the best commercially available amino acid sequenator marketed or as modified by published methods as of the filing date of this application, or (2) to homogeneity by SDS-PAGE under non-reducing or reducing conditions using Coomassie blue or, preferably, silver stain. Homogeneity here means less than about 5% contamination with other source proteins. "Essentially pure" protein means a composition comprising at least about 90% by weight ofthe protein, based on total weight ofthe composition, preferably at least about 95% by weight. "Essentially homogeneous" protein means a composition comprising at least about 99% by weight of protein, based on total weight ofthe composition. "Biological property" when used in conjunction with either "WSX receptor" or "isolated WSX receptor" means having an effector or antigenic function or activity that is directly or indirectly caused or performed by native sequence WSX receptor (whether in its native or denatured conformation). Effector functions include ligand binding; and enhancement of survival, differentiation and/or proliferation of cells (especially proliferation of cells). However, effector functions do not include possession of an epitope or antigenic site that is capable of cross-reacting with antibodies raised against native sequence WSX receptor. "Biological property" when used in conjunction with either "OB protein" or "isolated OB protein" means having an effector function that is directly or indirectly caused or performed by native sequence OB protein. Effector functions of native sequence OB protein include WSX receptor binding and activation; and enhancement of differentiation and/or proliferation of cells expressing this receptor (as determined in the thymidine incorporation assay, for example). A "biologically active" OB protein is one which possesses a biological property of native sequence OB protein. A "functional derivative" ofa native sequence OB protein is a compound having a qualitative biological property in common with a native sequence OB protein. "Functional derivatives" include, but are not limited to, fragments of native sequence OB proteins and derivatives of native sequence OB proteins and their fragments, provided that they have a biological activity in common with a corresponding native sequence OB protein. The term "derivative" encompasses both amino acid sequence variants of OB protein and covalent modifications thereof. The phrase "long half-life" as used in connection with OB derivatives, concerns OB derivatives having a longer plasma half-life and/or slower clearance than a corresponding native sequence OB protein. The long half-life derivatives preferably will have a half-life at least about 1.5-times longer than a native OB protein; more preferably at least about 2-times longer than a native OB protein, more preferably at least about 3-time longer than a native OB protein. The native OB protein preferably is that ofthe individual to be treated. An "antigenic function" means possession of an epitope or antigenic site that is capable of cross-reacting with antibodies raised against native sequence WSX receptor. The principal antigenic function of a WSX receptor is that it binds with an affinity of at least about 10" L/mole to an antibody raised against native sequence WSX receptor. Ordinarily, the polypeptide binds with an affinity of at least about 10 ' L/mole. The antibodies used to define "antigenic function" are rabbit polyclonal antibodies raised by formulating the WSX receptor in Freund's complete adjuvant, subcutaneously injecting the formulation, and boosting the immune response by intraperitoneal injection of the formulation until the titer of the anti-WSX receptor or antibody plateaus. "Biologically active" when used in conjunction with either "WSX receptor" or "isolated WSX receptor" means a WSX receptor polypeptide that exhibits or shares an effector function of native sequence WSX receptor and that may (but need not) in addition possess an antigenic function. A principal effector function of the WSX receptor is its ability to induce proliferation of CD34+ human umbilical cord blood cells in the colony assay described in Example 8. "Antigenically active" WSX receptor is defined as a polypeptide mat possesses an antigenic function of WSX receptor and that may (but need not) in addition possess an effector function. "Percent amino acid sequence identity" is defined herein as the percentage of amino acid residues in the candidate sequence that are identical with the residues in the native sequence, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity, and not considering any conservative substitutions as part of the sequence identity. None of N-terminal, C-terminal, or internal extensions, deletions, or insertions into the candidate sequence shall be construed as affecting sequence identity or homology. A "thymidine incoφoration assay" can be used to screen for molecules which activate the WSX receptor. In order to perform this assay, IL-3 dependent BaO cells (Palacios et al. Cell, 41 :727-734 ( 1985)) are stably transfected with full length native sequence WSX receptor as described in Example 4. The WSX receptor/BaO cells so generated are starved of IL-3 for, e.g., 24 hours in a humidified incubator at 37°C in 5%C02 and air. Following IL-3 starvation, the cells are plated out in 96 well culture dishes with, or without, a test sample containing a potential agonist (such test samples are optionally diluted) and cultured for 24 hours in a cell culture incubator. 20μl of serum free RPMI media containing 1 μCi of ^H thymidine is added to each well for the last 6-8 hours. The cells are then harvested in 96 well filter plates and washed with water. The filters are then counted using a Packard Top Count Microplate Scintillation Counter, for example. Agonists are expected to induce a statistically significant increase (to a P value of 0.05) in H uptake, relative to control. Preferred agonists leads to an increase in 3 H uptake which is at least two fold of that ofthe control. An "isolated" WSX receptor nucleic acid molecule is a nucleic acid molecule that is identified and separated from at least one contaminant nucleic acid molecule with which it is ordinarily associated in the natural source ofthe WSX receptor nucleic acid. An isolated WSX receptor nucleic acid molecule is other than in the form or setting in which it is found in nature. Isolated WSX receptor nucleic acid molecules therefore are distinguished from the WSX receptor nucleic acid molecule as it exists in natural cells. However, an isolated WSX receptor nucleic acid molecule includes WSX receptor nucleic acid molecules contained in cells that ordinarily express WSX receptor where, for example, the nucleic acid molecule is in a chromosomal location different from that of natural cells. The expression "control sequences" refers to DNA sequences necessary for the expression of an operably linked coding sequence in a particular host organism. The control sequences that are suitable for prokaryotes, for example, include a promoter, optionally an operator sequence, a ribosome binding site, and possibly, other as yet poorly understood sequences. Eukaryotic cells are known to utilize promoters, polyadenylation signals, and enhancers. Nucleic acid is "operably linked" when it is placed into a functional relationship with another nucleic acid sequence. For example, DNA for a presequence or secretory leader is operably linked to DNA for a polypeptide if it is expressed as a preprotein that participates in the secretion of the polypeptide; a promoter or enhancer is operably linked to a coding sequence if it affects the transcription of the sequence; or a ribosome binding site is operably linked to a coding sequence if it is positioned so as to facilitate translation. Generally, "operably linked" means that the DNA sequences being linked are contiguous, and, in the case of a secretory leader, contiguous and in reading phase. However, enhancers do not have to be contiguous. Linking is accomplished by ligation at convenient restriction sites. If such sites do not exist, the synthetic oligonucleotide adaptors or linkers are used in accordance with conventional practice. As used herein, the expressions "cell," "cell line," and "cell culture" are used interchangeably and all such designations include progeny. Thus, the words "transformants" and "transformed cells" include the primary subject cell and cultures derived therefrom without regard for the number of transfers. It is also understood that all progeny may not be precisely identical in DNA content, due to deliberate or inadvertent mutations. Mutant progeny that have the same function or biological activity as screened for in the originally transformed cell are included. Where distinct designations are intended, it will be clear from the context. The term "antibody" is used in the broadest sense and specifically covers monoclonal antibodies, antibody compositions with polyepitopic specificity, bispecific antibodies, diabodies, and single-chain molecules, as well as antibody fragments (e.g., Fab, F(ab')2, and Fv), so long as they exhibit the desired biological activity. The term "monoclonal antibody" as used herein refers to an antibody obtained from a population of substantially homogeneous antibodies, i.e., the individual antibodies comprising the population are identical except for possible naturally occurring mutations that may be present in minor amounts. Monoclonal antibodies are highly specific, being directed against a single antigenic site. Furthermore, in contrast to conventional (polyclonal) antibody preparations which typically include different antibodies directed against different determinants (epitopes), each monoclonal antibody is directed against a single determinant on the antigen. In addition to their specificity, the monoclonal antibodies are advantageous in that they are synthesized by the hybridoma culture, uncontaminated by other immunoglobulins. The modifier "monoclonal" indicates the character ofthe antibody as being obtained from a substantially homogeneous population of antibodies, and is not to be construed as requiring production of the antibody by any particular method For example, the monoclonal antibodies to be used in accordance with the present invention may be made by the hybridoma method first described by Kohler et al . Nature 256 495 (1975), or may be made by recombinant DNA methods (see, e g , U S Patent No 4,816,567 (Cabilly e/ α/ )) The "monoclonal antibodies" may also be isolated from phage antibody libraries using the techniques described in Clackson et al , Nature 352 624-628 (1991 ) and Marks et al , J Mol Biol 222 581-597 (1991), for example The monoclonal antibodies herein specifically include "chimeric" antibodies (immunoglobulins) in which a portion ofthe heavy and/or light chain is identical with or homologous to corresponding sequences in antibodies derived from a particular species or belonging to a particular antibody class or subclass, while the remainder ofthe cha (s) is identical with or homologous to corresponding sequences in antibodies derived from another species or belonging to another antibody class or subclass, as well as fragments of such antibodies, so long as they exhibit the desired biological activity (Cabilly et al , supra, Morrison et al , Proc Natl Acad Sci USA, S I 6851 -6855 (1984)) "Humanized" forms of non-human (e g , murine) antibodies are chimeric immunoglobulins, immunoglobulin chains or fragments thereof (such as Fv, Fab, Fab', F(ab')2 or other antigen-binding subsequences of antibodies) which contain minimal sequence derived from non-human immunoglobulin For the most part, humanized antibodies are human immunoglobulins (recipient antibody) in which residues from a complementary-determining region (CDR) ofthe recipient are replaced by residues from a CDR of a non- human species (donor antibody) such as mouse, rat or rabbit having the desired specificity, affinity, and capacity In some instances, Fv framework region (FR) residues of the human immunoglobulin are replaced by corresponding non-human residues Furthermore, humanized antibodies may comprise residues which are found neither in the recipient antibody nor in the imported CDR or framework sequences These modifications are made to further refine and optimize antibody performance In general, the humanized antibody will comprise substantially all of at least one, and typically two, variable domains, in which all or substantially all ofthe CDR regions correspond to those ofa non-human immunoglobulin and all or substantially all ofthe FR regions are those ofa human immunoglobulin sequence The humanized antibody optimally also will comprise at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin For further details, see Jones et al , Nature 321 522-525 (1986), Reichmann et al , Nature 332 323-329 (1988), and Presta, Curr Op Struct Biol 2 593-596 (1992) The humanized antibody includes a Primatized antibody wherein the antigen-binding region of the antibody is derived from an antibody produced by immunizing macaque monkeys with the antigen of interest The term "hypervaπable region" when used herein refers to the amino acid residues of an antibody which are responsible for antigen-binding The hypervaπable region comprises ammo acid residues from a "complementarity determmmg region" or "CDR" (/ e residues 24-34 (LI ), 50-56 (L2) and 89-97 (L3) in the light chain variable domain and 31-35 (HI), 50-65 (H2) and 95-102 (H3) m the heavy chain variable domain, Kabat et al , Sequences of Proteins of Immunological Interest, 5th Ed Public Health Service, National Institutes of Health, Bethesda, MD ( 1991 )) and/or those residues from a "hypervaπable loop" (ι e residues 26-32 (L 1), 50- 52 (L2) and 91-96 (L3) in the light chain variable domain and 26-32 (HI), 53-55 (H2) and 96-101 (H3) m the heavy chain variable domain; Chothia and Lesk J. Mol. Biol 196:901-917 (1987)). "Framework" or "FR" residues are those variable domain residues other than the hypervariable region residues as herein defined. "Non-immunogenic in a human" means that upon contacting the polypeptide of interest in a physiologically acceptable carrier and in a therapeutically effective amount with the appropriate tissue of a human, no state of sensitivity or resistance to the polypeptide of interest is demonstrable upon the second administration ofthe polypeptide of interest after an appropriate latent period (e.g., 8 to 14 days). By "agonist antibody" is meant an antibody which is able to activate native sequence WSX receptor. The agonist antibody of particular interest herein is one which mimics one or more (e.g. all) of the biological properties of naturally occurring WSX ligand, OB protein. In preferred embodiments, the agonist antibody has a quantitative biological property of OB protein which is within about two orders of magnitude, and preferably within about one order of magnitude, that of OB protein. The agonist antibody may bind to and activate WSX receptor and thereby stimulate proliferation and/or differentiation and/or maturation and/or survival of a cell which expresses the WSX receptor (e.g. WSX receptor variant 13.2). In this embodiment of the invention, the agonist antibody may be one which enhances proliferation and/or differentiation of a hematopoietic progenitor cell which expresses the WSX receptor at its cell surface; enhances proliferation and/or differentiation of lymphoid blood cell lineages; enhances proliferation and/or differentiation of myeloid blood cell lineages; and/or enhances proliferation and/or differentiation of erythroid blood cell lineages. The agonist antibody may display agonist activity upon binding to a chimeric receptor comprising the WSX receptor extracellular domain in the KIRA ELISA. The agonist antibody may stimulate -*H uptake in the thymidine incoφoration assay using a signaling WSX receptor (see above); decrease body weight and/or fat-depot weight and/or food intake in an obese mammal (e.g. in the oblob mouse); effect Ca influx in adipocytes; and/or activate downstream signaling molecules of OB protein. A "neutralizing antibody" is one which is able to block or significantly reduce an effector function of native sequence WSX receptor or OB protein. For example, a neutralizing antibody may inhibit or reduce WSX receptor activation by a WSX ligand as determined in the thymidine incoφoration assay or in a KIRA ELISA. The term "cytotoxic agent" as used herein refers to a substance mat inhibits or prevents the function of cells and/or causes destruction of cells. The term is intended to include radioactive isotopes (e.g., 1 , 1 , Y and Re ), chemotherapeutic agents, and toxins such as enzymaticaUy active toxins of bacterial, fungal, plant or animal origin, or fragments thereof. A "chemotherapeutic agent" is a chemical compound useful in the treatment of cancer. Examples of chemotherapeutic agents include Adriamycin, Doxorubicin, 5-Fluorouracil, Cytosine arabinoside ("Ara-C"), Cyclophosphamide, Thiotepa, Taxotere (docetaxel), Busulfan, Cytoxin, Taxol, Methotrexate, Cisplatin, Melphalan, Vinblastine, Bleomycin, Etoposide, Ifosfamide, Mitomycin C, Mitoxantrone, Vincreistine, Vinorelbine, Carboplatin, Teniposide, Daunomycin, Carminomycin, Aminopterin, Dactinomycin, Mitomycins, Esperamicins (see U.S. Pat. No. 4,675, 187), Melphalan and other related nitrogen mustards. The term "prodrug" as used in this application refers to a precursor or derivative form of a pharmaceutically active substance that is less cytotoxic to tumor cells compared to the parent drug and is capable of being enzymaticaUy activated or converted into the more active parent form. See, e.g., Wilman, "Prodrugs in Cancer Chemotherapy" Biochemical Society Transactions, 14, pp. 375-382, 615th Meeting Belfast (1986) and Stella et al , "Prodrugs A Chemical Approach to Targeted Drug Delivery," Directed Drug Delivery, Borchardt e/ cr/, (ed ), pp 247-267, Humana Press (1985) The prodrugs of this invention include, but are not limited to, phosphate-containing prodrugs, thiophosphate-containmg prodrugs, sulfate-containing prodrugs, peptide-containing prodrugs, D-amino acid-modified prodrugs, glycosylated prodrugs, β-lactam-containing prodrugs, optionally substituted phenoxyacetamide-containing prodrugs or optionally substituted phenylacetamide-containing prodrugs, 5-fluorocytosιne and other 5-fluorouπdιne prodrugs which can be converted into the more active cytotoxic free drug Examples of cytotoxic drugs that can be deπvatized into a prodrug form for use in this invention include, but are not limited to, those chemotherapeutic agents described above An "antagonist" ofthe WSX receptor and/or OB protein is a molecule which prevents, or interferes with, binding and/or activation ofthe WSX receptor or OB protein Such molecules can be screened for their ability to competitively inhibit WSX receptor activation by OB protein in the thymidine incoφoration assay disclosed herein, for example Examples of such molecules include WSX receptor ECD, WSX receptor immunoadhesin, neutralizing antibodies against WSX receptor or OB protein, small molecule and peptide antagonists, and antisense nucleotides against the WSX receptor or ob gene The phrase "enhancing proliferation ofa cell" encompasses the step of increasing the extent of growth and/or reproduction of the cell relative to an untreated cell either in vitro or in vivo An increase in cell proliferation cell culture can be detected by counting the number of cells before and after exposure to a molecule of interest The extent of proliferation can be quantified via microscopic examination ofthe degree of confluency Cell proliferation can also be quantified using the thymidine incorporation assay described herein By "enhancing differentiation ofa cell" is meant the act of increasing the extent ofthe acquisition or possession of one or more characteristics or functions which differ from that of the original cell (i e cell specialization) This can be detected by screening for a change in the phenotype of the cell (e g , identifying moφhological changes in the cell) A "hematopoietic progenitor cell" or "primitive hematopoietic cell" is one which is able to differentiate to form a more committed or mature blood cell type "Lymphoid blood cell lineages" are those hematopoietic precursor cells which are able to differentiate to form lymphocytes (B-cells or T-cells) Likewise, "lymphopoeisis" is the formation of lymphocytes "Erythroid blood cell lineages" are those hematopoietic precursor cells which are able to differentiate to form erythrocytes (red blood cells) and "erythropoeisis" is the formation of erythrocytes The phrase "myeloid blood cell lineages", for the puφoses herein, encompasses all hematopoietic precursor cells, other than lymphoid and erythroid blood cell lineages as defined above, and "myelopoiesis" involves the formation of blood cells (other than lymphocytes and erythrocytes) A "CD34+ cell population" is enriched for hematopoietic stem cells A CD34+ cell population can be obtained from umbilical cord blood or bone marrow, for example Human umbilical cord blood CD34+ cells can be selected for using lmmunomagnetic beads sold by Miltenyi (California), following the manufacturer's directions "Physiologically acceptable" carriers, excipients, or stabilizers are ones which are nontoxic to the cell or mammal being exposed thereto at the dosages and concentrations employed Often the physiologically acceptable carrier is an aqueous pH buffered solution. Examples of physiologically acceptable carriers include buffers such as phosphate, citrate, and other organic acids; antioxidants including ascorbic acid; low molecular weight (less than about 10 residues) polypeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, giutamine, asparagine, arginine or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; salt-forming counterions such as sodium; and or nonionic surfactants such as Tween, Pluronics or polyethylene glycol (PEG). As used herein, the term "salvage receptor binding epitope" refers to an epitope ofthe Fc region of an IgG molecule (e.g., IgG I, lgG2, lgG3, and IgG4) that is responsible for increasing the in vivo serum half-life of the IgG molecule. Exemplary salvage receptor binding epitope sequences include HQNLSDGK (SEQ ID NO:39); HQNISDGK (SEQ ID NO:40); HQSLGTQ (SEQ ID NO:41); VISSHLGQ (SEQ ID NO:42); and PKNSSMISNTP (SEQ ID NO:43). The term "cytokine" is a generic term for proteins released by one cell population which act on another cell as intercellular mediators. Examples of such cytokines are lymphokines, monokines, and traditional polypeptide hormones. Included among the cytokines are OB protein; growth hormones such as human growth hormone, N-methionyl human growth hormone, and bovine growth hormone; parathyroid hormone; thyroxine; insulin; proinsulin; relaxin; prorelaxin; glycoprotein hormones such as follicle stimulating hormone (FSH), thyroid stimulating hormone (TSH), and luteinizing hormone (LH); hepatic growth factor; fibroblast growth factor; prolactin; placental lactogen; tumor necrosis factor-α and -β; mullerian-inhibiting substance; mouse gonadotropin-associated peptide; inhibin; activin; vascular endothelial growth factor; integrin; thrombopoietin (TPO); nerve growth factors such as NGF-β; platelet-growth factor; transforming growth factors (TGFs) such as TGF-α and TGF-β; insulin-like growth factor-I and -II; erythropoietin (EPO); osteoinductive factors; interferons such as interferon-α, -β, and -γ; colony stimulating factors (CSFs) such as macrophage-CSF (M- CSF); granulocyte-macrophage-CSF (GM-CSF); and granulocyte-CSF (G-CSF); interleukins (ILs) such as IL- 1 , IL- l α, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, 1L-8, IL-9, IL-l 1 , IL- 12; and other polypeptide factors including leukemia inhibitory factor (LIF) and kit ligand (KL). As used herein, the term cytokine includes proteins from natural sources or from recombinant cell culture and biologically active equivalents of the native sequence cytokines. A "lineage-specific cytokine" is one which acts on relatively committed cells in the hematopoietic cascade and gives rise to an expansion in blood cells of a single lineage. Examples of such cytokines include EPO, TPO, and G-CSF. "Treatment" refers to both therapeutic treatment and prophylactic or preventative measures. Those in need of treatment include those already with the disorder as well as those in which the disorder is to be prevented. The term "obesity" is used to designate a condition of being overweight associated with excessive bodily fat. The desirable weight for a certain individual depends on a number of factors including sex, height, age, overall built, etc. The same factors will determine when an individual is considered obese. The determination of an optimum body weight for a given individual is well within the skill of an ordinary physician. "Mammal" for puφoses of treatment refers to any animal classified as a mammal, including humans, domestic and farm animals, and zoo, sports, or pet animals, such as dogs, horses, cats, cows, etc. Preferably, the mammal is human. By "solid phase" is meant a non-aqueous matrix to which a reagent of interest (e.g., the WSX receptor or an antibody thereto) can adhere. Examples of solid phases encompassed herein include those formed partially or entirely of glass (e.g., controlled pore glass), polysaccharides (e.g., agarose), polyacrylamides, polystyrene, polyvinyl alcohol and silicones. In certain embodiments, depending on the context, the solid phase can comprise the well of an assay plate; in others it is a purification column (e.g., an affinity chromatography column). This term also includes a discontinuous solid phase of discrete particles, such as those described in U.S. Patent No. 4,275,149. II. Modes for Carrying Out the Invention The present invention is based on the discovery ofthe WSX receptor. The experiments described herein demonstrate that this molecule is a cytokine receptor which appears to play a role in enhancing proliferation and/or differentiation of hematopoietic cells. In particular, this receptor has been found to be present in enriched human stem cell populations, thus indicating that WSX ligands, such as agonist antibodies, may be used to stimulate proliferation of hematopoietic stem cells/progenitor cells. Other uses for this receptor will be apparent from the following discussion. A description follows as to how WSX receptor or OB proteins may be prepared. a. Preparation of WSX Receptor or OB Protein Techniques suitable for the production of WSX receptor or OB protein are well known in the art and include isolating WSX receptor or OB protein from an endogenous source ofthe polypeptide, peptide synthesis (using a peptide synthesizer) and recombinant techniques (or any combination of these techniques). The preferred technique for production of WSX receptor or OB protein is a recombinant technique to be described below. Most ofthe discussion below pertains to recombinant production of WSX receptor or OB protein by culturing cells transformed with a vector containing WSX receptor or OB protein nucleic acid and recovering the polypeptide from the cell culture. It is further envisioned that the WSX receptor or OB protein of this invention may be produced by homologous recombination, as provided for in WO 91/06667, published 16 May 1991. Briefly, this method involves transforming primary human cells containing a WSX receptor or OB protein-encoding gene with a construct (i.e., vector) comprising an amplifiable gene (such as dihydrofolate reductase (DHFR) or others discussed below) and at least one flanking region of a length of at least about 150 bp that is homologous with a DNA sequence at the locus ofthe coding region ofthe WSX receptor or OB protein gene to provide amplification ofthe WSX receptor or OB protein gene. The amplifiable gene must be at a site that does not interfere with expression of the WSX receptor or OB protein gene. The transformation is conducted such that the construct becomes homologously integrated into the genome ofthe primary cells to define an amplifiable region. Primary cells comprising the construct are then selected for by means ofthe amplifiable gene or other marker present in the construct. The presence ofthe marker gene establishes the presence and integration ofthe construct into the host genome No further selection ofthe primary cells need be made, since selection will be made in the second host If desired, the occurrence ofthe homologous recombination event can be determined by employing PCR and either sequencing the resulting amplified D A sequences or determining the appropriate lengm ofthe PCR fragment when DNA from correct homologous integrants is present and expanding only those cells contaming such fragments Also if desired, the selected cells may be amplified at this point by stressing the cells with the appropriate amplifying agent (such as methotrexate if the amplifiable gene is DHFR), so that multiple copies ofthe target gene are obtained Preferably, however, the amplification step is not conducted until after the second transformation described below After the selection step, DNA portions ofthe genome, sufficiently large to include the entire amplifiable region, are isolated from the selected primary cells Secondary mammalian expression host cells are then transformed with these genomic DNA portions and cloned, and clones are selected that contain the amplifiable region The amplifiable region is then amplified by means of an amplifying agent if not already amplified in the primary cells Finally, the secondary expression host cells now comprising multiple copies of the amplifiable region containing WSX receptor or OB protein are grown so as to express the gene and produce the protein i. Isolation of DNA Encoding WSX Receptor or OB Protein The DNA encoding WSX receptor or OB protein may be obtained from any cDNA library prepared from tissue believed to possess the WSX receptor or OB protein mRNA and to express it at a detectable level Accordingly, WSX receptor or OB protein DNA can be conveniently obtained from a cDNA library prepared from mammalian fetal liver The WSX receptor or OB protein-encoding gene may also be obtained from a genomic library or by oligonucleotide synthesis Libraries are screened with probes (such as antibodies to the WSX receptor or OB protein, or oligonucleotides of about 20-80 bases) designed to identify the gene of interest or the protein encoded by it Screening the cDNA or genomic library with the selected probe may be conducted using standard procedures as described in chapters 10-12 of Sambrook et al , Molecular Cloning A Laboratory Manual (New York Cold Spring Harbor Laboratory Press, 1989) An alternative means to isolate the gene encoding WSX receptor or OB protein is to use PCR methodology as described in section 14 of Sambrook et al , supra A preferred method of practicing mis invention is to use carefully selected oligonucleotide sequences to screen cDNA libraries from various human tissues, preferably human fetal liver The oligonucleotide sequences selected as probes should be of sufficient length and sufficiently unambiguous that false positives are minimized The oligonucleotide must be labeled such that it can be detected upon hybridization to DNA in the library being screened The preferred method of labeling is to use -"P-labeled ATP with polynucleotide kinase, as is well known in the art, to radiolabel the oligonucleotide However, other methods may be used to label the oligonucleotide, including, but not limited to, biotinylation or enzyme labeling Amino acid sequence variants of WSX receptor or OB protein are prepared by introducing appropriate nucleotide changes into the WSX receptor or OB protem DNA, or by synthesis ofthe desired WSX receptor or OB protem Such variants represent insertions, substitutions, and/or specified deletions of, residues within or at one or both ofthe ends ofthe amino acid sequence of a naturally occurring human WSX receptor or OB protem, such as the WSX receptor variants shown in Figs 2A-B or the human OB protein of Zhang et al , supra Preferably, these variants represent insertions and/or substitutions within or at one or both ends of the mature sequence, and/or insertions, substitutions and/or specificed deletions within or at one or both of the ends ofthe signal sequence ofthe WSX receptor or OB protein. Any combination of insertion, substitution, and/or specified deletion is made to arrive at the final construct, provided that the final construct possesses the desired biological activity as defined herein. The amino acid changes also may alter post-translational processes of the WSX receptor or OB protein, such as changing the number or position of glycosylation sites, altering the membrane anchoring characteristics, and/or altering the intracellular location of the WSX receptor or OB protein by inserting, deleting, or otherwise affecting the leader sequence ofthe WSX receptor or OB protein. Variations in the native sequence as described above can be made using any of the techniques and guidelines for conservative and non-conservative mutations set forth in U.S. Pat. No. 5,364,934. These include oligonucleotide-mediated (site-directed) mutagenesis, alanine scanning, and PCR mutagenesis. See also, for example, Table I therein and the discussion surrounding this table for guidance on selecting amino acids to change, add, or delete. ii. Insertion of Nucleic Acid into Replicable Vector The nucleic acid (e.g., cDNA or genomic DNA) encoding the WSX receptor or OB protein is inserted into a replicable vector for further cloning (amplification of the DNA) or for expression. Many vectors are available. The vector components generally include, but are not limited to, one or more of the following: a signal sequence, an origin of replication, one or more marker genes, an enhancer element, a promoter, and a transcription termination sequence. (1) Signal sequence component The WSX receptor or OB proteins of this invention may be produced recombinantly not only directly, but also as a fusion polypeptide with a heterologous polypeptide, which is preferably a signal sequence or other polypeptide having a specific cleavage site at the N-terminus ofthe mature protein or polypeptide. In general, the signal sequence may be a component ofthe vector, or it may be a part ofthe WSX receptor or OB protein DNA that is inserted into the vector. The heterologous signal sequence selected preferably is one that is recognized and processed (i.e., cleaved by a signal peptidase) by the host cell. For prokaryotic host cells that do not recognize and process the native WSX receptor or OB protein signal sequence, the signal sequence is substituted by a prokaryotic signal sequence selected, for example, from the group ofthe alkaline phosphatase, penicillinase, lpp, or heat-stable enterotoxin II leaders. For yeast secretion the native signal sequence may be substituted by, e.g., the yeast invertase leader, α factor leader (including Saccharomyces and Kluyveromyces α- fector leaders, the latter described in U.S. Pat. No. 5,010,182 issued 23 April 1991), or acid phosphatase leader, the C. albicans glucoamylase leader (EP 362, 179 published 4 April 1990), or the signal described in WO 90/13646 published 15 November 1990. In mammalian cell expression the native signal sequence (e.g., the WSX receptor or OB protein presequence that normally directs secretion of WSX receptor or OB protein from human cells in vivo) is satisfactory, although other mammalian signal sequences may be suitable, such as signal sequences from other animal WSX receptors or OB proteins, and signal sequences from secreted polypeptides ofthe same or related species, as well as viral secretory leaders, for example, the heφes simplex gD signal. The DNA for such precursor region is ligated in reading frame to DNA encoding the mature WSX receptor or OB protein. (2) Origin of replication component Both expression and cloning vectors contain a nucleic acid sequence that enables the vector to replicate in one or more selected host cells Generally, in cloning vectors this sequence is one that enables the vector to replicate independently ofthe host chromosomal DNA, and includes origins of replication or autonomously replicating sequences Such sequences are well known for a variety of bacteria, yeast, and viruses The origin of replication from the plasmid pBR322 is suitable for most Gram-negative bacteria, the 2μ plasmid origin is suitable for yeast, and various viral origins (SV40, polyoma, adenovirus, VSV or BPV) are useful for cloning vectors in mammalian cells Generally, the origin of replication component is not needed for mammalian expression vectors (the SV40 origin may typically be used only because it contains the early promoter) Most expression vectors are "shuttle" vectors, ; , they are capable of replication in at least one class of organisms but can be transfected into another organism for expression For example, a vector is cloned in E coli and then the same vector is transfected into yeast or mammalian cells for expression even though it is not capable of replicating independently ofthe host cell chromosome DNA may also be amplified by insertion into the host genome This is readily accomplished using Bacillus species as hosts, for example, by including in the vector a DNA sequence that is complementary to a sequence found in Bacillus genomic DNA Transfection of Bacillus with this vector results in homologous recombination with the genome and insertion of WSX receptor or OB protein DNA However, the recovery of genomic DNA encoding WSX receptor or OB protein is more complex than that of an exogenously replicated vector because restriction enzyme digestion is required to excise the WSX receptor or OB protein DNA (3) Selection gene component Expression and cloning vectors should contain a selection gene, also termed a selectable marker This gene encodes a protem necessary for the survival or growth of transformed host cells grown in a selective culture medium Host cells not transformed with the vector containing the selection gene will not survive in the culture medium Typical selection genes encode protems that (a) confer resistance to antibiotics or other toxins, e , ampicillin, neomycin, methotrexate, or tetracyclme, (b) complement auxotrophic deficiencies, or (c) supply critical nutrients not available from complex media, e g , the gene encoding D-alanine racemase for Bacilli One example ofa selection scheme utilizes a drug to arrest growth ofa host cell Those cells that are successfully transformed with a heterologous gene produce a protein conferring drug resistance and thus survive the selection regimen Examples of such dominant selection use the drugs neomycin, mycophenolic acid and hygromycin Another example of suitable selectable markers for mammalian cells are those that enable the identification of cells competent to take up the WSX receptor or OB protein nucleic acid, such as DHFR or thymidine kinase The mammalian cell transformants are placed under selection pressure that only the transformants are uniquely adapted to survive by virtue of having taken up the marker Selection pressure is imposed by cultunng the transformants under conditions in which the concentration of selection agent in the medium is successively changed, thereby leadmg to amplification of both the selection gene and the DNA that encodes WSX receptor or OB protein Amplification is the process by which genes in greater demand for the production of a protein critical for growth are reiterated in tandem within the chromosomes of successive generations of recombinant cells Increased quantities of WSX receptor or OB protem are synthesized from the amplified DNA. Other examples of amplifiable genes include metallothionein-I and -II, preferably primate metallothionein genes, adenosine deaminase, ornithine decarboxylase, etc. For example, cells transformed with the DHFR selection gene are first identified by culturing all ofthe transformants in a culture medium that contains methotrexate (Mtx), a competitive antagonist of DHFR. An appropriate host cell when wild-type DHFR is employed is the Chinese hamster ovary (CHO) cell line deficient in DHFR activity, prepared and propagated as described by Urlaub et al, Proc. Natl. Acad. Sci. USA 77:4216 (1980). The transformed cells are then exposed to increased levels of methotrexate. This leads to the synthesis of multiple copies of the DHFR gene, and, concomitantly, multiple copies of other DNA comprising the expression vectors, such as the DNA encoding WSX receptor or OB protein. This amplification technique can be used with any otherwise suitable host, e.g., ATCC No. CCL61 CHO-Kl, notwithstanding the presence of endogenous DHFR if, for example, a mutant DHFR gene that is highly resistant to Mtx is employed (EP 1 17,060). Alternatively, host cells (particularly wild-type hosts that contain endogenous DHFR) transformed or co-transformed with DNA sequences encoding WSX receptor or OB protein, wild-type DHFR protein, and another selectable marker such as aminoglycoside 3'-phosphotransferase (APH) can be selected by cell growth in medium containing a selection agent for the selectable marker such as an aminoglycosidic antibiotic, e.g., kanamycin, neomycin, or G418. See U.S. Patent No. 4,965,199. A suitable selection gene for use in yeast is the trp\ gene present in the yeast plasmid YRp7 (Stinchcomb et al, Nature 282:39 (1979)). The trp] gene provides a selection marker for a mutant strain of yeast lacking the ability to grow in tryptophan, for example, ATCC No. 44076 or PEP4- 1. Jones, Genetics 85:12 (1977). The presence ofthe trp\ lesion in the yeast host cell genome then provides an effective environment for detecting transformation by growth in the absence of tryptophan. Similarly, Z.e«2-deficient yeast strains (ATCC 20,622 or 38,626) are complemented by known plasmids bearing the Leul gene. In addition, vectors derived from the 1.6 μm circular plasmid pKDl can be used for transformation of Kluyveromyces yeasts. Bianchi et al, Curr. Genet. 12:185 (1987). More recently, an expression system for large-scale production of recombinant calf chymosin was reported for K. lactis. Van den Berg, Bio/Technology 8:135 (1990). Stable multi-copy expression vectors for secretion of mature recombinant human serum albumin by industrial strains of Kluyveromyces have also been disclosed. Fleer et al. , Bio/Technology 9:968-975 ( 1991 ). (4) Promoter Component Expression and cloning vectors usually contain a promoter that is recognized by the host organism and is operably linked to the WSX receptor or OB protein nucleic acid. Promoters are untranslated sequences located upstream (5') to the start codon ofa structural gene (generally within about 100 to 1000 bp) that control the transcription and translation of particular nucleic acid sequence, such as the WSX receptor or OB protein nucleic acid sequence, to which they are operably linked. Such promoters typically fall into two classes, inducible and constitutive. Inducible promoters are promoters that initiate increased levels of transcription from DNA under their control in response to some change in culture conditions, e.g., the presence or absence ofa nutrient or a change in temperature. At this time a large number of promoters recognized by a variety of potential host cells are well known. These promoters are operably linked to WSX receptor or OB protein-encoding DNA by removing the promoter from the source DNA by restriction enzyme digestion and inserting the isolated promoter sequence into the vector. Both the native WSX receptor or OB protein promoter sequence and many heterologous promoters may be used to direct amplification and/or expression of the WSX receptor or OB protein DNA. However, heterologous promoters are preferred, as they generally permit greater transcription and higher yields of WSX receptor or OB protein as compared to the native WSX receptor or OB protein promoter. Promoters suitable for use with prokaryotic hosts include the β-lactamase and lactose promoter systems (Chang et al, Nature 275:615 (1978); Goeddel et al, Nature 281 :544 (1979)), alkaline phosphatase, a tryptophan (tφ) promoter system (Goeddel, Nucleic Acids Res. 8:4057 ( 1980); EP 36,776), and hybrid promoters such as the tac promoter. deBoer et al, Proc. Natl. Acad. Sci. USA 80:21-25 (1983). However, other known bacterial promoters are suitable. Their nucleotide sequences have been published, thereby enabling a skilled worker operably to ligate them to DNA encoding WSX receptor or OB protein (Siebenlist et al , Cell 20:269 (1980)) using linkers or adaptors to supply any required restriction sites. Promoters for use in bacterial systems also will contain a Shine-Dalgarno (S.D.) sequence operably linked to the DNA encoding WSX receptor or OB protein. Promoter sequences are known for eukaryotes. Virtually all eukaryotic genes have an AT-rich region located approximately 25 to 30 bases upstream from the site where transcription is initiated. Another sequence found 70 to 80 bases upstream from the start of transcription of many genes is a CXCAAT region where X may be any nucleotide. At the 3' end of most eukaryotic genes is an A ATA A A sequence that may be the signal for addition ofthe poly A tail to the 3' end ofthe coding sequence. All of these sequences are suitably inserted into eukaryotic expression vectors. Examples of suitable promoting sequences for use with yeast hosts include the promoters for 3- phosphoglycerate kinase (Hitzeman et al, J. Biol. Chem. 255:2073 (1980)) or other glycolytic enzymes (Hess et al, J. Adv. Enzyme Reg. 7: 149 (1968); Holland, Biochemistry 17:4900 (1978)), such as enolase, glyceraldehyde-3-phosρhate dehydrogenase, hexokinase, pyruvate decarboxylase, phosphofructokinase, glucose- 6-phosphate isomerase, 3-phosphoglycerate mutase, pyruvate kinase, triosephosphate isomerase, phosphoglucose isomerase, and glucokinase. Other yeast promoters, which are inducible promoters having the additional advantage of transcription controlled by growth conditions, are the promoter regions for alcohol dehydrogenase 2, isocytochrome C, acid phosphatase, degradative enzymes associated with nitrogen metabolism, metallothionein, glyceraldehyde-3-phos- phate dehydrogenase, and enzymes responsible for maltose and galactose utilization. Suitable vectors and promoters for use in yeast expression are further described in EP 73,657. Yeast enhancers also are advantageously used with yeast promoters. WSX receptor or OB protein transcription from vectors in mammalian host cells is controlled, for example, by promoters obtained from the genomes of viruses such as polyoma virus, fowlpox virus (UK 2,211,504 published 5 July 1989), adenovirus (such as Adenovirus 2), bovine papilloma virus, avian sarcoma virus, cytomegalovirus, a retrovirus, hepatitis-B virus and most preferably Simian Virus 40 (SV40), from heterologous mammalian promoters, e.g., the actin promoter or an immunoglobulin promoter, from heat-shock promoters, and from me promoter normally associated wim the WSX receptor or OB protein sequence, provided such promoters are compatible with the host cell systems. The early and late promoters of the SV40 virus are conveniently obtained as an SV40 restriction fragment that also contains the SV40 viral origin of replication. Fiers et al, Nature 273: 1 13 (1978); Mulligan et al, Science 209: 1422-1427 (1980); Pavlakis et al, Proc. Natl. Acad. Sci. USA 78:7398-7402 (1981 ). The immediate early promoter of the human cytomegalovirus is conveniently obtained as a HindlH E restriction fragment. Greenaway et al. Gene 18:355-360 (1982). A system for expressing DNA in mammalian hosts using the bovine papilloma virus as a vector is disclosed in U.S. Patent No. 4,419,446. A modification of this system is described in U.S. Patent No. 4,601,978. See also Gray et al, Nature 295:503-508 (1982) on expressing cDNA encoding immune interferon in monkey cells; Reyes et al, Nature 297:598-601 (1982) on expression of human β-interferon cDNA in mouse cells under the control ofa thymidine kinase promoter from heφes simplex virus; Canaani et al, Proc. Natl. Acad. Sci. USA 79:5166- 170 (1982) on expression ofthe human interferon β 1 gene in cultured mouse and rabbit cells; and Gorman et al, Proc. Natl. Acad. Sci. USA 79:6777-6781 (1982) on expression of bacterial CAT sequences in CV-1 monkey kidney cells, chicken embryo fibroblasts, Chinese hamster ovary cells, HeLa cells, and mouse NIH-3T3 cells using the Rous sarcoma virus long terminal repeat as a promoter. (5) Enhancer element component Transcription of a DNA encoding the WSX receptor or OB protein of this invention by higher eukaryotes is often increased by inserting an enhancer sequence into the vector. Enhancers are cis-acting elements of DNA, usually about from 10 to 300 bp, that act on a promoter to increase its transcription. Enhancers are relatively orientation and position independent, having been found 5' (Laimins et al, Proc. Natl. Acad. Sci. USA 78:993 (1981)) and 3' (Lusky et al, Mol. Cell Bio. 3: 1 108 (1983)) to the transcription unit, within an intron (Banerji et al, Cell 33:729 (1983)), as well as within the coding sequence itself. Osbome / α/., Mol. Cell Bio. 4: 1293 (1984). Many enhancer sequences are now known from mammalian genes (globin, elastase, albumin, α-fetoprotein, and insulin). Typically, however, one will use an enhancer from a eukaryotic cell virus. Examples include the SV40 enhancer on the late side of the replication origin (bp 100-270), the cytomegalovirus early promoter enhancer, the polyoma enhancer on the late side ofthe replication origin, and adenovirus enhancers. See also Yaniv, Nature 297: 17-18 (1982) on enhancing elements for activation of eukaryotic promoters. The enhancer may be spliced into the vector at a position 5' or 3' to the WSX receptor or OB protein-encoding sequence, but is preferably located at a site 5' from the promoter. (6) Transcription termination component Expression vectors used in eukaryotic host cells (yeast, fungi, insect, plant, animal, human, or nucleated cells from other multicellular organisms) will also contain sequences necessary for the termination of transcription and for stabilizing the mRNA. Such sequences are commonly available from the 5' and, occasionally 3', untranslated regions of eukaryotic or viral DNAs or cDNAs. These regions contain nucleotide segments transcribed as polyadenylated fragments in the untranslated portion of the mRNA encoding WSX receptor or OB protein . (7) Construction and analysis of vectors Construction of suitable vectors containing one or more of the above-listed components employs standard ligation techniques. Isolated plasmids or DNA fragments are cleaved, tailored, and re-ligated in the form desired to generate the plasmids required. For analysis to confirm correct sequences in plasmids constructed, the ligation mixtures are used to transform E. coli K12 strain 294 (ATCC 31 ,446) and successful transformants selected by ampicillin or tetracycline resistance where appropriate. Plasmids from the transformants are prepared, analyzed by restriction endonuclease digestion, and or sequenced by the method of Messing et al, Nucleic Acids Res. 9:309 ( 1981 ) or by the method of Maxam et al, Methods in Enzymology 65:499 (1980). Transient expression vectors Particularly useful in the practice of this invention are expression vectors that provide for the transient expression in mammalian cells of DNA encoding WSX receptor or OB protein. In general, transient expression involves the use of an expression vector that is able to replicate efficiently in a host cell, such that the host cell accumulates many copies ofthe expression vector and, in turn, synthesizes high levels of a desired polypeptide encoded by the expression vector. Sambrook et al, supra, pp. 16.17 - 16.22. Transient expression systems, comprising a suitable expression vector and a host cell, allow for the convenient positive identification of polypeptides encoded by cloned DNAs, as well as for the rapid screening of such polypeptides for desired biological or physiological properties. Thus, transient expression systems are particularly useful in the invention for puφoses of identifying analogs and variants of WSX receptor or OB protein that are biologically active WSX receptor or OB protein. (8) Suitable exemplary vertebrate cell vectors Other methods, vectors, and host cells suitable for adaptation to the synthesis of WSX receptor or OB protein in recombinant vertebrate cell culture are described in Gething et al. Nature 293:620-625 ( 1981 ); Mantei et al. , Nature 281 :40-46 ( 1979); EP 1 17,060; and EP 1 17,058. A particularly useful plasmid for mammalian cell culture expression of WSX receptor or OB protein is pRK5 (EP 307,247) or pSVI6B. WO 91/08291 published 13 June 1991. iii. Selection and Transformation of Host Cells Suitable host cells for cloning or expressing the DNA in the vectors herein are the prokaryote, yeast, or higher eukaryote cells described above. Suitable prokaryotes for this puφose include eubacteria, such as Gram-negative or Gram-positive organisms, for example, Enterobacteriaceae such as Escherichia, e.g., E. coli, Enterobacter, Erwinia, Klebsiella, Proteus, Salmonella, e.g.. Salmonella typhimurium, Serratia, e.g., Serratia marcescans, and Shigella, as well as Bacilli such as B. subtilis and B. licheniformis (e.g. , B. licheniformis 41 P disclosed in DD 266,710 published 12 April 1989), Pseudomonas such as P. aeruginosa, and Streptomyces. One preferred E. coli cloning host is E. coli 294 (ATCC 31,446), although other strains such as E coli B, E. coli XI 776 (ATCC 31,537), and E. coli W31 10 (ATCC 27,325) are suitable. These examples are illustrative rather than limiting. Strain W3110 is a particularly preferred host or parent host because it is a common host strain for recombinant DNA product fermentations. Preferably, the host cell should secrete minimal amounts of proteolytic enzymes. For example, strain W31 10 may be modified to effect a genetic mutation in the genes encoding proteins, with examples of such hosts including E. coli W31 10 strain 27C7. The complete genotype of 27C7 is tonAΔ ptr3phoAΔE15 Δ(argF-lac) 169 ompTΔ degP4Ikarτ " . Strain 27C7 was deposited on 30 October 1991 in the American Type Culture Collection as ATCC No. 55,244. Alternatively, the strain of E. coli having mutant periplasmic protease disclosed in U.S. Patent No. 4,946,783 issued 7 August 1990 may be employed. Alternatively still, methods of cloning, e.g., PCR or other nucleic acid polymerase reactions, are suitable. In addition to prokaryotes, eukaryotic microbes such as filamentous fungi or yeast are suitable cloning or expression hosts for WSX receptor or OB protein-encoding vectors Saccharomyces cerevisiae, or common baker's yeast, is the most commonly used among lower eukaryotic host microorganisms However, a number of other genera, species, and strains are commonly available and useful herein, such as Schizosaccharomyces pombe (Beach et al , Nature, 290 140 (1981), EP 139,383 published 2 May 1985), Kluyveromyces hosts (U S Patent No 4,943,529, Fleer et al , supra) such as, e , K lactts (MW98-8C, CBS683, CBS4574), K fragilis (ATCC 12,424), K bulgartcus (ATCC 16,045), K wickeramn (ATCC 24, 178), K waltti (ATCC 56,500), K drosophilarum (ATCC 36,906, Van den Berg et al , supra), K thermotolerans, and K marxianus yarrowia (EP 402,226), Ptchia pasto is (EP 183,070, Sreeknshna et al , J Basic Microbiol 28 265-278 (1988)), Candida, Trichoderma reesia (EP 244,234), Neurospora crassa (Case et al , Proc Natl Acad Sci USA 76 5259-5263 (1979)), Schwanmomyces such as Schwanniomyces occidentalis (EP 394,538 published 31 October 1990), and filamentous fungi such as, e g , Neurospora, Penicillium, Tolypocladtum (WO 91/00357 published 10 January 1991), and Aspergillus hosts such as A mdulαns (Ballance et αl , Biochem Biophys Res Commun 112 284-289 (1983), Tilbum e/α/ , Gene 26205-221 (1983), Yelton e/ α/ , Proc Nαtl Acαd Sci USA 81 1470-1474 (1984)) and A niger Kelly et αl , EMBO J 4 475-479 (1985) Suitable host cells for the expression of glycosylated WSX receptor or OB protein are derived from multicellular organisms Such host cells are capable of complex processing and glycosylation activities In principle, any higher eukaryotic cell culture is workable, whether from vertebrate or invertebrate culture Examples of invertebrate cells include plant and insect cells Numerous baculoviral strains and variants and corresponding permissive insect host cells from hosts such as Spodopterajrugiperda (cateφillar), Aedes aegypti (mosquito), Aedes alboptctus (mosquito), Drosophda melanogaster (fruitfly), and Bombyx mort have been identified See, e g , Luckow et al , Bio/Technology 6 47-55 (1988), Miller et al , in Genetic Engineering, Setlow et al , eds , Vol 8 (Plenum Publishing, 1986), pp 277-279, and Maeda et al , Nature 315 592-594 (1985) A variety of viral strains for transfection are publicly available, e g , the L-l variant of Autographa caltfornica NPV and the Bm-5 strain of Bombyx mort NPV, and such viruses may be used as the virus herein according to the present invention, particularly for transfection o\ Spodoplera frugtperda cells Plant cell cultures of cotton, corn, potato, soybean, petunia, tomato, and tobacco can be utilized as hosts Typically, plant cells are transfected by incubation with certain strains of the bacterium Agrobactenum tumefaciens, which has been previously manipulated to contain the WSX receptor or OB protein-encoding DNA During incubation ofthe plant cell culture with A tumefaciens, the DNA encodmg the WSX receptor or OB protein is transferred to the plant cell host such that it is transfected, and will, under appropriate conditions, express the WSX receptor or OB protein-encoding DNA In addition, regulatory and signal sequences compatible with plant cells are available, such as the nopal me synthase promoter and polyadenylation signal sequences Depicker et al , J Mol Appl Gen 1 :561 (1982) In addition, DNA segments isolated from the upstream region ofthe T-DNA 780 gene are capable of activating or increasing transcription levels of plant- expressible genes in recombinant DNA-containing plant tissue EP 321 , 196 published 21 June 1989 However, interest has been greatest in vertebrate cells, and propagation of vertebrate cells culture (tissue culture) has become a routine procedure See, e g , Tissue Culture, Academic Press, Kruse and Patterson, editors (1973) Examples of useful mammalian host cell lines are monkey kidney CV1 line transformed by SV40 (COS-7, ATCC CRL 1651); human embryonic kidney line (293 or 293 cells subcloned for growth in suspension culture, Graham et al, J. Gen Virol. 36:59 (1977)); baby hamster kidney cells (BHK, ATCC CCL 10); Chinese hamster ovary cellsADHFR (CHO, Urlaub et al, Proc. Natl. Acad. Sci. USA 77:4216 (1980)); mouse sertoli cells (TM4, Mather, Biol. Reprod. 23:243-251 (1980)); monkey kidney cells (CV1 ATCC CCL 70); African green monkey kidney cells (VERO-76, ATCC CRL-1587); human cervical carcinoma cells (HELA, ATCC CCL 2); canine kidney cells (MDCK, ATCC CCL 34); buffalo rat Iiver cells (BRL 3A, ATCC CRL 1442); human lung cells (WI38, ATCC CCL 75); human liver cells (Hep G2, HB 8065); mouse mammary tumor (MMT 060562, ATCC CCL51); TRI cells (Mather et al, Annals N. Y. Acad. Sci. 383:44-68 (1982)); MRC 5 cells; FS4 cells; and a human hepatoma line (Hep G2). Host cells are transfected and preferably transformed with the above-described expression or cloning vectors for WSX receptor or OB protein production and cultured in conventional nutrient media modified as appropriate for inducing promoters, selecting transformants, or amplifying the genes encoding the desired sequences. Transfection refers to the taking up of an expression vector by a host cell whether or not any coding sequences are in fact expressed. Numerous methods of transfection are known to the ordinarily skilled artisan, for example, CaPO^ and electroporation. Successful transfection is generally recognized when any indication ofthe operation of this vector occurs within the host cell. Transformation means introducing DNA into an organism so that the DNA is replicable, either as an extrachromosomal element or by chromosomal integrant. Depending on the host cell used, transformation is done using standard techniques appropriate to such cells. The calcium treatment employing calcium chloride, as described in section 1.82 of Sambrook et al, supra, or electroporation is generally used for prokaryotes or other cells that contain substantial cell-wall barriers. Infection with Agrobacterium tumefaciens is used for transformation of certain plant cells, as described by Shaw et al, Gene 23:315 (1983) and WO 89/05859 published 29 June 1989. In addition, plants may be transfected using ultrasound treatment as described in WO 91/00358 published 10 January 1991. For mammalian cells without such cell walls, the calcium phosphate precipitation method of Graham et al, Virology 52:456-457 (1978) is preferred. General aspects of mammalian cell host system transformations have been described in U.S. Pat. No. 4,399,216 issued 16 August 1983. Transformations into yeast are typically carried out according to the method of Van Solingen / α/., Bad. 130:946 (1977) and Hsiao et al, Proc. Natl. Acad. Sci. USA 76:3829 (1979). However, other methods for introducing DNA into cells, such as by nuclear microinjection, electroporation, bacterial protoplast fusion with intact cells, or polycations, e.g., polybrene, polyornithine, etc., may also be used. For various techniques for transforming mammalian cells, see Keown et al, Methods in Enzymology 185:527-537 (1990) and Mansour et al, Nature 336:348-352 (1988). iv. Culturing the Host Cells Prokaryotic cells used to produce the WSX receptor or OB protein of this invention are cultured in suitable media as described generally in Sambrook et al, supra. The mammalian host cells used to produce the WSX receptor or OB protein of this invention may be cultured in a variety of media. Commercially available media such as Ham's F10 (Sigma), Minimal Essential Medium ((MEM), Sigma), RPMI- 1640 (Sigma), and Dulbecco's Modified Eagle's Medium ((DMEM), Sigma) are suitable for culturing the host cells. In addition, any ofthe media described in Ham et al Meth. Enz. 58:44 (1979), Barnes et al. Anal BiochemΛQ2:255 (1980), U.S. Pat. Nos. 4,767,704; 4,657,866; 4,927,762; 4,560,655; or 5,122,469; WO 90/03430; WO 87/00195; or U.S. Patent Re. 30,985 may be used as culture media for the host cells. Any of these media may be supplemented as necessary with hormones and/or other growth factors (such as insulin, transferrin, or epidermal growth factor), salts (such as sodium chloride, calcium, magnesium, and phosphate), buffers (such as HEPES), nucieosides (such as adenosine and thymidine), antibiotics (such as GENTAMYCIN drug), trace elements (defined as inorganic compounds usually present at final concentrations in the micromolar range), and glucose or an equivalent energy source. Any other necessary supplements may also be included at appropriate concentrations that would be known to those skilled in the art. The culture conditions, such as temperature, pH, and the like, are those previously used with the host cell selected for expression, and will be apparent to the ordinarily skilled artisan. In general, principles, protocols, and practical techniques for maximizing the productivity of mammalian cell cultures can be found in Mammalian Cell Biotechnology: a Practical Approach, M. Butler, ed. (IRL Press, 1991 ). The host cells referred to in this disclosure encompass cells in culture as well as cells that are within a host animal. v. Detecting Gene Amplification/Expression Gene amplification and/or expression may be measured in a sample directly, for example, by conventional Southern blotting, Northern blotting to quantitate the transcription of mRNA (Thomas, Proc. Natl. Acad. Sci. USA 77:5201-5205 (1980)), dot blotting (DNA analysis), or in situ hybridization, using an appropriately labeled probe, based on the sequences provided herein. Various labels may be employed, most commonly radioisotopes, particularly P. However, other techniques may also be employed, such as using biotin-modified nucleotides for introduction into a polynucleotide. The biotin then serves as the site for binding to avidin or antibodies, which may be labeled with a wide variety of labels, such as radionuclides, fluorescers, enzymes, or the like. Alternatively, antibodies may be employed that can recognize specific duplexes, including DNA duplexes, RNA duplexes, and DNA-RNA hybrid duplexes or DNA-protein duplexes. The antibodies in turn may be labeled and the assay may be carried out where the duplex is bound to a surface, so that upon the formation of duplex on the surface, the presence of antibody bound to the duplex can be detected. Gene expression, alternatively, may be measured by immunological methods, such as immunohistochemical staining of tissue sections and assay of cell culture or body fluids, to quantitate directly the expression of gene product. With immunohistochemical staining techniques, a cell sample is prepared, typically by dehydration and fixation, followed by reaction with labeled antibodies specific for the gene product coupled, where the labels are usually visually detectable, such as enzymatic labels, fluorescent labels, luminescent labels, and the like. A particularly sensitive staining technique suitable for use in the present invention is described by Hsu et al, Am. J. Clin. Path. 75:734-738 (1980). Antibodies useful for immunohistochemical staining and/or assay of sample fluids may be either monoclonal or polyclonal, and may be prepared as described herein. vi. Purification of WSX Receptor or OB Protein WSX receptor (e.g., WSX receptor ECD) or OB protein preferably is recovered from the culture medium as a secreted polypeptide, although it also may be recovered from host cell lysates. If the WSX receptor is membrane-bound, it can be released from the membrane using a suitable detergent solution (e.g. Triton-X 100) When WSX receptor or OB protein is produced in a recombinant cell other than one of human origin, the WSX receptor or OB protein is completely free of proteins or polypeptides of human origin. However, it is necessary to purify WSX receptor or OB protein from recombinant cell proteins or polypeptides to obtain preparations that are substantially homogeneous as to WSX receptor or OB protein. As a first step, the culture medium or lysate is centrifuged to remove particulate cell debris. WSX receptor or OB protein thereafter is purified from contaminant soluble proteins and polypeptides, with the following procedures being exemplary of suitable purification procedures: by fractionation on an ion-exchange column; ethanol precipitation; reverse phase HPLC; chromatography on silica or on a cation-exchange resin such as DEAE; chromatofocusing; SDS- PAGE; ammonium sulfate precipitation; gel filtration using, for example, Sephadex G-75™; and protein A Sepharose™ columns to remove contaminants such as IgG. WSX receptor or OB protein variants in which residues have been deleted, inserted, or substituted are recovered in the same fashion as native sequence WSX receptor or OB protein, taking account of any substantial changes in properties occasioned by the variation. Immunoaffϊnity columns such as a rabbit polyclonal anti-WSX receptor or OB protein column can be employed to absorb the WSX receptor or OB protein variant by binding it to at least one remaining immune epitope. A protease inhibitor such as phenyl methyl sulfonyl fluoride (PMSF) also may be useful to inhibit proteolytic degradation during purification, and antibiotics may be included to prevent the growth of adventitious contaminants. vii. Covalent Modifications Covalent modifications of WSX receptor or OB protein are included within the scope of this invention. Both native sequence WSX receptor or OB protein and amino acid sequence variants ofthe WSX receptor or OB protein may be covalently modified. One type of covalent modification ofthe WSX receptor or OB protein is introduced into the molecule by reacting targeted amino acid residues ofthe WSX receptor or OB protein with an organic derivatizing agent that is capable of reacting with selected side chains or the N- or C-terminal residues ofthe WSX receptor or OB protein. Cysteinyl residues most commonly are reacted wim α-haloacetates (and corresponding amines), such as chloroacetic acid or chloroacetamide, to give carboxymethyl or carboxyamidomethyl derivatives. Cysteinyl residues also are derivatized by reaction with bromotrifluoroacetone, α-bromo-β-(5-imidozoyl)proρionic acid, chloroacetyl phosphate, N-alkylmaleimides, 3-nitro-2-pyridyl disulfide, methyl 2-pyridyl disulfide, p- chloromercuribenzoate, 2-chloromercuri-4-nitrophenol, or chloro-7-nitrobenzo-2-oxa-l ,3-diazole. Histidyl residues are derivatized by reaction with diethylpyrocarbonate at pH 5.5-7.0 because this agent is relatively specific for the histidyl side chain. Para-bromophenacyl bromide also is useful; the reaction is preferably performed in 0.1 M sodium cacodylate at pH 6.0. Lysinyl and amino terminal residues are reacted with succinic or other carboxylic acid anhydrides. Derivatization with these agents has the effect of reversing the charge ofthe lysinyl residues. Other suitable reagents for derivatizing α-amino-containing residues include imidoesters such as methyl picolinimidate, pyridoxal phosphate, pyridoxal, chloroborohydride, trinitrobenzenesulfonic acid, O-methylisourea, 2,4- pentanedione, and transaminase-catalyzed reaction with glyoxylate. Arginyl residues are modified by reaction with one or several conventional reagents, among them phenylglyoxal, 2,3-butanedione, 1 ,2-cyclohexanedione, and ninhydrin. Derivatization of arginine residues requires that the reaction be performed under alkaline conditions because of the high pK a of the guanidine functional group. Furthermore, these reagents may react with the groups of lysine as well as with the arginine epsilon-amino group. The specific modification of tyrosyl residues may be made, with particular interest in introducing spectral labels into tyrosyl residues by reaction with aromatic diazonium compounds or tetranitromethane. Most commonly, N-acetylimidizole and tetranitromethane are used to form O-acetyl tyrosyl species and 3-nitro 1 if n i derivatives, respectively. Tyrosyl residues are iodinated using J I or lJ I to prepare labeled proteins for use in radioimmunoassay, the chloramine T method being suitable. Carboxyl side groups (aspartyl or glutamyl) are selectively modified by reaction with carbodiimides (R- N=C=N-R'), where R and R' are different alkyl groups, such as l-cyclohexyl-3-(2-moφholinyl-4-ethyl) carbodiimide or l-ethyl-3-(4-azonia-4,4-dimethylpentyl) carbodiimide. Furthermore, aspartyl and glutamyl residues are converted to asparaginyl and glutaminyl residues by reaction with ammonium ions. Derivatization with bifunctional agents is useful for crosslinking WSX receptor or OB protein to a water-insoluble support matrix or surface for use in the method for purifying anti-WSX receptor or OB protein antibodies, and vice-versa. Commonly used crosslinking agents include, e.g., l , l -bis(diazoacetyl)-2- phenylethane, glutaraldehyde, N-hydroxysuccinimide esters, for example, esters with 4-azidosalicylic acid, homobifunctional imidoesters, including disuccinimidyl esters such as 3,3'-dithiobis(succinimidylpropionate), and bifunctional maleimides such as bis-N-maleimido-l ,8-octane. Derivatizing agents such as methyl-3-((p- azidophenyl)dithio)propioimidate yield photoactivatable intermediates that are capable of forming crosslinks in the presence of light. Alternatively, reactive water-insoluble matrices such as cyanogen bromide-activated carbohydrates and the reactive substrates described in U.S. Patent Nos. 3,969,287; 3,691,016; 4,195,128; 4,247,642; 4,229,537; and 4,330,440 are employed for protein immobilization. Glutaminyl and asparaginyl residues are frequently deamidated to the corresponding glutamyl and aspartyl residues, respectively. These residues are deamidated under neutral or basic conditions. The deamidated form of these residues falls within me scope of this invention. Other modifications include hydroxylation of proline and lysine, phosphorylation of hydroxyl groups of seryl or threonyl residues, methylation ofthe α-amino groups of lysine, arginine, and histidine side chains (T.E. Creighton, Proteins: Structure and Molecular Properties, W.H. Freeman & Co., San Francisco, pp. 79-86 (1983)), acetylation ofthe N-terminal amine, and amidation of any C-terminal carboxyl group. Another type of covalent modification ofthe WSX receptor or OB protein included within the scope of this invention comprises altering the native glycosylation pattern ofthe polypeptide. By altering is meant deleting one or more carbohydrate moieties found in native WSX receptor or OB protein, and/or adding one or more glycosylation sites that are not present in the native WSX receptor or OB protein. Glycosylation of polypeptides is typically either N-linked or O-linked N-hnked refers to the attachment ofthe carbohydrate moiety to the side chain of an asparagine residue The tπpeptide sequences asparagine-X- seπne and asparagine-X-threonine, where X is any amino acid except proline, are the recognition sequences for enzymatic attachment ofthe carbohydrate moiety to the asparagine side chain Thus, the presence of either of these tnpeptide sequences in a polypeptide creates a potential glycosylation site O-Iinked glycosylation refers to the attachment of one ofthe sugars N-aceylgalactosamine, galactose, or xylose to a hydroxylamino acid, most commonly serine or threonine, although 5-hydroxyprolme or 5-hydroxylysιne may also be used Addition of glycosylation sites to the WSX receptor or OB protein is conveniently accomplished by altering the amino acid sequence such that it contains one or more ofthe above-described tnpeptide sequences (for N-linked glycosylation sites) The alteration may also be made by the addition of, or substitution by, one or more serine or threonine residues to the native WSX receptor or OB protein sequence (for O-lmked glycosylation sites) For ease, the WSX receptor or OB protein amino acid sequence is preferably altered through changes at the DNA level, particularly by mutating the DNA encoding the WSX receptor or OB protein at preselected bases such that codons are generated that will translate into the desired amino acids The DNA mutatιon(s) may be made using methods described above and in U S Pat No 5,364,934, su ra Another means of increasing the number of carbohydrate moieties on the WSX receptor or OB protein is by chemical or enzymatic coupling of glycosides to the polypeptide These procedures are advantageous in that they do not require production ofthe polypeptide in a host cell that has glycosylation capabilities for N- or O-lmked glycosylation Depending on the coupling mode used, the sugar(s) may be attached to (a) arginine and histidine, (b) free carboxyl groups, (c) free sulfhydryl groups such as those of cysteine, (d) free hydroxyl groups such as those of serine, threonine, or hydroxyproline, (e) aromatic residues such as those of phenylalanine, tyrosine, or tryptophan, or (f) the amide group of giutamine These methods are described in WO 87/05330 published 1 1 September 1987, and Apiin et al CRC Crit Rev Biochem 259-306 (1981) Removal of carbohydrate moieties present on the WSX receptor or OB protein may be accomplished chemically or enzymaticaUy Chemical deglycosylation requires exposure ofthe polypeptide to the compound trifluoromethanesulfonic acid, or an equivalent compound This treatment results in the cleavage of most or all sugars except the linking sugar (N-acetylglucosamine or N-acetylgalactosamine), while leaving the polypeptide intact Chemical deglycosylation is described by Hakimuddin, ef al , Arch Biochem Biophys 259 52 (1987) and by Edge et al , Anal Biochem 1 18 131 (1981) Enzymatic cleavage of carbohydrate moieties on polypeptides can be achieved by the use ofa variety of endo- and exo-glycosidases as described by Thotakura et al , Meth Enzymol 138 350 (1987) Glycosylation at potential glycosylation sites may be prevented by me use ofthe compound tunicamycin as described by Duskin et al , J Biol Chem 257 3105 (1982) Tunicamycin blocks the formation of protein-N- glycoside linkages Another type of covalent modification of WSX receptor or OB protein comprises linking the WSX receptor or OB protein to one of a variety of nonproteinaceous polymers, e g , polyethylene glycol, polypropylene glycol, or polyoxyalkylenes, in the manner set forth in U S Patent Nos 4,640,835, 4,496,689, 4,301,144, 4,670,417, 4,791,192 or 4,179,337 Since it is often difficult to predict in advance the characteristics of a variant WSX receptor or OB protein, it will be appreciated that some screening ofthe recovered variant will be needed to select the optimal variant. A change in the immunological character ofthe WSX receptor or OB protein molecule, such as affinity for a given antibody, is also able to be measured by a competitive-type immunoassay. The WSX receptor variant is assayed for changes in the ability ofthe protein to induce cell proliferation in the colony assay of Example 8. Other potential modifications of protein or polypeptide properties such as redox or thermal stability, hydrophobicity, susceptibility to proteolytic degradation, or the tendency to aggregate with carriers or into multimers are assayed by methods well known in the art. viii. Epitope-Tagged WSX Receptor or OB Protein This invention encompasses chimeric polypeptides comprising WSX receptor or OB protein fused to a heterologous polypeptide. A chimeric WSX receptor or OB protein is one type of WSX receptor or OB protein variant as defined herein. In one preferred embodiment, the chimeric polypeptide comprises a fusion ofthe WSX receptor or OB protein with a tag polypeptide which provides an epitope to which an anti-tag antibody can selectively bind. The epitope tag is generally provided at the amino- or carboxyl- terminus ofthe WSX receptor or OB protein. Such epitope-tagged forms ofthe WSX receptor or OB protein are desirable as the presence thereof can be detected using a labeled antibody against the tag polypeptide. Also, provision of the epitope tag enables the WSX receptor or OB protein to be readily purified by affinity purification using the anti-tag antibody. Affinity purification techniques and diagnostic assays involving antibodies are described later herein. Tag polypeptides and their respective antibodies are well known in the art. Examples include the flu HA tag polypeptide and its antibody 12CA5 (Field et al, Mol. Cell. Biol. 8:2159-2165 (1988)); the c-myc tag and the 8F9, 3C7, 6E10, G4, B7 and 9E10 antibodies thereto (Evan et al, Molecular and Cellular Biology 5:3610-3616 (1985)); and the Heφes Simplex virus glycoprotein D (gD) tag and its antibody. Paborsky et al. Protein Engineering 3(6):547-553 (1990). Other tag polypeptides have been disclosed. Examples include the Flag-peptide (Hopp et al. , BioTechnology 6: 1204- 1210 (1988)); the KT3 epitope peptide (Martin et al. , Science 255:192-194 (1992)); an α-tubulin epitope peptide (Skinner et al, J. Biol Chem. 266:15163-15166 (1991)); and the T7 gene 10 protein peptide tag. Lutz-Freyermuth et al, Proc. Natl. Acad. Sci. USA 87:6393-6397 (1990). Once the tag polypeptide has been selected, an antibody thereto can be generated using the techniques disclosed herein. The general methods suitable for the construction and production of epitope-tagged WSX receptor or OB protein are the same as those disclosed hereinabove. WSX receptor or OB protein-tag polypeptide fusions are most conveniently constructed by fusing the cDNA sequence encoding the WSX receptor or OB protein portion in-frame to the tag polypeptide DNA sequence and expressing the resultant DNA fusion construct in appropriate host cells. Ordinarily, when preparing the WSX receptor or OB protein-tag polypeptide chimeras ofthe present invention, nucleic acid encoding the WSX receptor or OB protein will be fused at its 3' end to nucleic acid encoding the N-terminus ofthe tag polypeptide, however 5' fusions are also possible. Epitope-tagged WSX receptor or OB protein can be conveniently purified by affinity chromatography using the anti-tag antibody. The matrix to which the affinity antibody is attached is most often agarose, but other matrices are available (e.g. controlled pore glass or poly(styrenedivinyl)benzene). The epitope-tagged WSX receptor or OB protem can be eluted from the affinity column by varying the buffer pH or ionic strength or adding chaotropic agents, for example ix. WSX Receptor or OB Protein Immunoadhesins Chimeras constructed from a receptor sequence linked to an appropriate immunoglobulin constant domain sequence (immunoadhesins) are known in the art Immunoadhesins reported in the literature include fusions of the T cell receptor* (Gascoigne et al , Proc Natl Acad Set USA 84 2936-2940 (1987)), CD4* (Capon et at , Nature 331 525-531 (1989), Traunecker e/ α/ , Mrtwre 339 68-70 (1989), Zettmeissl et al , DNA CeU Biol USA 9 347-353 (1990), Byrn et al , Nature 344 667-670 ( 1990)), L-selectm (homing receptor) ((Watson et al , J Cell Biol 1 10 2221-2229 (1990), Watson et al , Nature 349 164-167 ( 1991 )), CD44* (Aruffo / α/ , Ce// 61 1303-1313 (1990)), CD28* and B7* (Linsley et al , J Exp Med 173 721 -730 (1991)), CTLA-4* (Lisley et al , J Exp Med 174 561 -569 (1991)), CD22* (Stamenkovic et al , Cell 66 1 133-1 144 (1991)), TNF receptor (Ashkenazi et al , Proc Natl Acad Set USA 88 10535-10539 (1991), Lesslauer et al , Eur J Immunol 27 2883-2886 (1991), Peppel / a/ , ./ Exp Med 174 1483-1489 (1991)), NP receptors (Bennett et al , J Biol Chem 266 23060-23067 (1991)), and IgE receptor α * (Ridgway et al J Cell Biol 1 15 abstr 1448 (1991)), where the asterisk (*) indicates that the receptor is member of the immunoglobulin superf amily The simplest and most straightforward immunoadhesin design combines the binding regιon(s) ofthe "adhesin" protein with the hmge and Fc regions of an immunoglobulin heavy cham Ordinarily, when preparing the WSX receptor or OB-immunoglobulm chimeras ofthe present invention, nucleic acid encoding OB protein or the extracellular domain of the WSX receptor will be fused C-terminally to nucleic acid encoding the N- terminus of an immunoglobulin constant domain sequence, however N-terminal fusions are also possible For OB-immunoglobulin chimeras, an OB protein fragment which retains the ability to bind to the WSX receptor may be employed Typically, in such fusions the encoded chimeric polypeptide will retain at least functionally active hinge, CH2 and CH3 domams ofthe constant region of an immunoglobulin heavy chain Fusions are also made to the C-terminus ofthe Fc portion ofa constant domain, or immediately N-termmal to the CH 1 ofthe heavy chain or the corresponding region of the light chain The precise site at which the fusion is made is not critical, particular sites are well known and may be selected in order to optimize the biological activity, secretion or binding characteristics ofthe WSX receptor or OB-immunoglobulm chimeras In some embodiments, the WSX receptor or OB-immunogiobulin chimeras are assembled as monomers, or hetero- or homo-multimers, and particularly as dimers or tetramers, essentially as illustrated in WO 91/08298 In a preferred embodiment, the OB protem sequence or WSX receptor extracellular domain sequence is fused to the N-terminus ofthe C-terminal portion of an antibody (in particular the Fc domain), containing the effector functions of an immunoglobulin, e g immunoglobulin G 1 (IgG 1 ) It is possible to fuse the entire heavy chain constant region to the OB protein or WSX receptor extracellular domain sequence However, more preferably, a sequence beginning in the hmge region just upstream ofthe papa cleavage site (which defines IgG Fc chemically, residue 216, taking the first residue of heavy chain constant region to be 114, or analogous sites of other immunoglobulins) is used in the fusion In a particularly preferred embodiment, the OB protein or WSX receptor amino acid sequence is fused to the hinge region, CH2 and CH3, or the CHI , hinge, CH2 and CH3 domains of an IgGI, IgG2, or IgG3 heavy chain. The precise site at which the fusion is made is not critical, and the optimal site can be determined by routine experimentation. In some embodiments, the WSX receptor or OB-immunoglobulin chimeras are assembled as multimers, and particularly as homo-dimers or -tetramers. Generally, these assembled immunoglobulins will have known unit structures. A basic four chain structural unit is the form in which IgG, IgD, and IgE exist. A four unit is repeated in the higher molecular weight immunoglobulins; IgM generally exists as a pentamer of basic four units held toge er by disulfide bonds. IgA globulin, and occasionally IgG globulin, may also exist in multimeric form in serum. In the case of multimer, each four unit may be the same or different. Various exemplary assembled WSX receptor or OB-immunoglobulin chimeras within the scope herein are schematically diagrammed below: (a) AC L -AC L ; (b) AC H -(AC H , AC L -AC H , AC L -V H C H , or V L C L -AC H ); (c) AC L -AC H -(AC L -AC H , AC L -V H C H , V L C L -AC H , or V L C L -V H C H ); (d) AC L -V H C H -(AC H , or AC L -V H C H , or V L C L -AC H ); (e) V L C L -AC H -(AC L -V H C H , or V L C L -AC H ); and (f) (A-Y) n -(V L C L -V H C H ) 2 , wherein each A represents identical or different OB protein or WSX receptor amino acid sequences; V j^ is an immunoglobulin light chain variable domain; Vι_ j is an immunoglobulin heavy chain variable domain; C^ is an immunoglobulin light chain constant domain; Cι_ j is an immunoglobulin heavy chain constant domain; n is an integer greater than 1 ; Y designates the residue of a covalent cross-linking agent. In the interests of brevity, the foregoing structures only show key features; they do not indicate joining (J) or other domains ofthe immunoglobulins, nor are disulfide bonds shown. However, where such domains are required for binding activity, they shall be constructed as being present in the ordinary locations which they occupy in the immunoglobulin molecules. Alternatively, the OB protein or WSX receptor extracellular domain sequence can be inserted between immunoglobulin heavy chain and light chain sequences such that an immunoglobulin comprising a chimeric heavy chain is obtained. In this embodiment, the OB protein or WSX receptor sequence is fused to the 3' end of an immunoglobulin heavy chain in each arm of an immunoglobulin, either between the hinge and the CH2 domain, or between the CH2 and CH3 domains. Similar constructs have been reported by Hoogenboom et al, Mol. Immunol, 28: 1027-1037 (1991). Although the presence of an immunoglobulin light chain is not required in the immunoadhesins ofthe present invention, an immunoglobulin light chain might be present either covalently associated to an OB protein or WSX receptor-immunoglobulin heavy chain fusion polypeptide, or directly fused to the WSX receptor extracellular domain or OB protein. In the former case, DNA encoding an immunoglobulin light chain is typically coexpressed with the DNA encodmg the OB protein or WSX receptor-immunoglobulin heavy chain fusion protein Upon secretion, the hybrid heavy chain and the light chain will be covalently associated to provide an lmmunoglobu n-like structure comprising two disulfide-linked immunoglobulin heavy chain-light chain pairs Methods suitable for the preparation of such structures are, for example, disclosed in U S Patent No 4,816,567 issued 28 March 1989 In a preferred embodiment, the immunoglobulin sequences used in the construction of the immunoadhesins ofthe present invention are from an IgG immunoglobulin heavy chain constant domain For human immunoadhesins, the use of human IgG I and IgG3 immunoglobulin sequences is preferred A major advantage of using IgGI is that IgGI immunoadhesins can be purified efficiently on immobilized protein A In contrast, purification of lgG3 requires protein G, a significantly less versatile medium However, other structural and functional properties of immunoglobulins should be considered when choosing the lg fusion partner for a particular immunoadhesin construction For example, the IgG3 hinge is longer and more flexible, so it can accommodate larger adhesin domams that may not fold or function properly when fused to IgG 1 Another consideration may be valency, IgG immunoadhesins are bivalent homodimers, whereas lg subtypes like IgA and IgM may give rise to dimeπc or pentameπc structures, respectively, of the basic lg homodimer unit For immunoadhesins designed for m vivo application, the pharmacokmetic properties and the effector functions specified by the Fc region are important as well Although IgG 1 , IgG2 and lgG4 all have in vivo half-lives of 21 days, their relative potencies at activating the complement system are different lgG4 does not activate complement, and IgG2 is significantly weaker at complement activation than IgG I Moreover, unlike IgG I , IgG2 does not bind to Fc receptors on mononuclear cells or neutrophils While IgG3 is optimal for complement activation, its in vivo half-life is approximately one third of the other IgG isotypes Another important consideration for immunoadhesins designed to be used as human therapeutics is the number of allotypic variants of me particular isotype In general, IgG isotypes with fewer serologically-defined allotypes are preferred For example, IgGI has only four serologically-defined allotypic sites, two of which (G lm and 2) are located in the Fc region, and one of these sites G lml, is non-immunogenic In contrast, there are 12 serologically-defined allotypes in IgG3, all of which are in the Fc region, only three of these sites (G3m5, 1 1 and 21) have one allotype which is nonimmunogenic Thus, the potential immunogenicity of a γ3 immunoadhesin is greater than that of a γ 1 immunoadhesin With respect to the parental immunoglobulin, a useful joining point is just upstream ofthe cyste es of the hmge that form the disulfide bonds between the two heavy chains In a frequently used design, the codon for the C-terminal residue ofthe WSX receptor or OB protein part ofthe molecule is placed directly upstream ofthe codons for the sequence DKTHTCPPCP (SEQ ID NO 44) ofthe IgGI hinge region The general methods suitable for the construction and expression of immunoadhesins are the same as those disclosed hereinabove with regard to WSX receptor and OB protein Immunoadhesins are most conveniently constructed by fusing the cDNA sequence encoding the WSX receptor or OB protem portion in- frame to an lg cDNA sequence However, fusion to genomic lg fragments can also be used (see, e g Gascoigne et al , Proc Natl Acad Set USA, 84 2936-2940 (1987), Amffo et al , Cell 61 1303-1313 (1990), Stamenkovic et al , Cell 66 1133- 1144 ( 1 91 )) The latter type of fusion requires the presence of lg regulatory sequences for expression cDNAs encoding IgG heavy-chain constant regions can be isolated based on published sequence from cDNA libraries derived from spleen or peripheral blood lymphocytes, by hybridization or by polymerase chain reaction (PCR) techniques. The cDNAs encoding the WSX receptor or OB protein and lg parts of the immunoadhesin are inserted in tandem into a plasmid vector that directs efficient expression in the chosen host cells. For expression in mammalian cells, pRK5-based vectors (Schall et al, Cell 61 :361-370 (1990)) and CDM8-based vectors (Seed, Nature 329:840 (1989)) can be used. The exact junction can be created by removing the extra sequences between the designed junction codons using oligonucleotide-directed deletional mutagenesis (Zoller et al. Nucleic Acids Res. 10:6487 (1982); Capon et al, Nature 337:525-531 (1989)). Synthetic oligonucleotides can be used, in which each half is complementary to the sequence on either side of the desired junction; ideally, these are 36 to 48-mers. Alternatively, PCR techniques can be used to join the two parts ofthe molecule in-frame with an appropriate vector. The choice of host cell line for the expression ofthe immunoadhesin depends mainly on the expression vector. Another consideration is the amount of protein that is required. Milligram quantities often can be produced by transient transfections. For example, the adenovirus El A-transformed 293 human embryonic kidney cell line can be transfected transiently with pRK5-based vectors by a modification ofthe calcium phosphate method to allow efficient immunoadhesin expression. CDM8-based vectors can be used to transfect COS cells by the DEAE-dextran method (Aruffo et al, Cell 61 : 1303-1313 (1990); Zettmeissl et al, DNA Cell Biol US 9:347-353 (1990)). If larger amounts of protein are desired, the immunoadhesin can be expressed after stable transfection ofa host cell line. For example, a pRK5-based vector can be introduced into Chinese hamster ovary (CHO) cells in the presence of an additional plasmid encoding dihydrofolate reductase (DHFR) and conferring resistance to G418. Clones resistant to G418 can be selected in culture; these clones are grown in the presence of increasing levels of DHFR inhibitor methotrexate; clones are selected, in which the number of gene copies encoding the DHFR and immunoadhesin sequences is co-amplified. If the immunoadhesin contains a hydrophobic leader sequence at its N-terminus, it is likely to be processed and secreted by the transfected cells. The expression of immunoadhesins with more complex structures may require uniquely suited host cells; for example, components such as light chain or J chain may be provided by certain myeloma or hybridoma cell hosts (Gascoigne e/ α/., 1987, supra. Martin et al, J. Virol. 67:3561-3568 (1993)). Immunoadhesins can be conveniently purified by affinity chromatography. The suitability of protein A as an affinity ligand depends on the species and isotype ofthe immunoglobulin Fc domain that is used in the chimera. Protein A can be used to purify immunoadhesins that are based on human γ 1 , γ2, or γ4 heavy chains (Lindmark ef α/., J Immunol. Meth. 62:1-13 (1983)). Protein G is recommended for all mouse isotypes and for human γ3 (Guss et al, EMBOJ. 5:1567-1575 (1986)). The matrix to which the affinity ligand is attached is most often agarose, but other matrices are available. Mechanically stable matrices such as controlled pore glass or poly(styrenedivinyl)benzene allow for faster flow rates and shorter processing times than can be achieved with agarose. The conditions for binding an immunoadhesin to the protein A or G affinity column are dictated entirely by the characteristics ofthe Fc domain; that is, its species and isotype. Generally, when the proper ligand is chosen, efficient binding occurs directly from unconditioned culture fluid. One distinguishing feature of immunoadhesins is that, for human γ l molecules, the binding capacity for protein A is somewhat diminished relative to an antibody ofthe same Fc type. Bound immunoadhesin can be efficiently eluted either at acidic pH (at or above 3.0), or in a neutral pH buffer containing a mildly chaotropic salt. This affinity chromatography step can result in an immunoadhesin preparation that is >95% pure. Other me ods known in the art can be used in place of, or in addition to, affinity chromatography on protein A or G to purify immunoadhesins. Immunoadhesins behave similarly to antibodies in thiophilic gel chromatography (Hutchens et al, Anal. Biochem. 159:217-226 (1986)) and immobilized metal chelate chromatography (Al-Mashikhi et al, J. Dair Sci. 71 :1756-1763 (1988)). In contrast to antibodies, however, their behavior on ion exchange columns is dictated not only by their isoelectric points, but also by a charge dipole that may exist in the molecules due to their chimeric nature. If desired, the immunoadhesins can be made bispecific. Thus, the immunoadhesins of the present invention may combine a WSX receptor extracellular domain and a domain, such as the extracellular domain, of another cytokine receptor subunit. Exemplary cytokine receptors from which such bispecific immunoadhesin molecules can be made include TPO (or mpl ligand), EPO, G-CSF, IL-4, IL-7, GH, PRL, IL-3, GM-CSF, IL-5, IL-6, LIF, OSM,CNTF and IL-2 receptors. Alternatively, an OB protein domain may be combined with another cytokine, such as those exemplified herein, in the generation ofa bispecific immunoadhesin For bispecific molecules, trimeric molecules, composed ofa chimeric antibody heavy chain in one arm and a chimeric antibody heavy chain-light chain pair in the other arm of their antibody-like structure are advantageous, due to ease of purification. In contrast to antibody-producing quadromas traditionally used for the production of bispecific immunoadhesins, which produce a mixture often tetramers, cells transfected with nucleic acid encoding the three chains of a trimeric immunoadhesin structure produce a mixture of only three molecules, and purification ofthe desired product from this mixture is correspondingly easier. x. Long Half-Life Derivatives of OB Protein Prefered OB protein functional derivatives for use in the methods ofthe present invention include OB- immunoglobulin chimeras (immunoadhesins) and other longer half-life molecules. Techniques for generating OB protein immunoadhesins have been described above. The prefered OB immunoadhesin is made according to the techniques described in Example 1 1 below. Other derivatives of the OB proteins, which possess a longer half-life than the native molecules comprise the OB protein or an OB-immunoglobulin chimera covalently bonded to a nonproteinaceous polymer. The nonproteinaceous polymer ordinarily is a hydrophilic synthetic polymer, ; ' . e. , a polymer not otherwise found in nature. However, polymers which exist in nature and are produced by recombinant or in vitro methods are useful, as are polymers which are isolated from native sources. Hydrophilic polyvinyl polymers fall within the scope of this invention, e.g. polyvinylalcohol and polyvinylpyrrolidone. Particularly useful are polyalkylene ethers such as polyethylene glycol (PEG); polyelkylenes such as polyoxyethylene, polyoxypropylene, and block copolymers of polyoxyethylene and polyoxypropylene (Pluronics™); polymethacrylates; carbomers; branched or unbranched polysaccharides which comprise the saccharide monomers D-mannose, D- and L-galactose, fucose, fructose, D-xylose, L-arabinose, D-glucuronic acid, sialic acid, D-galacturonic acid, D-mannuronic acid (e.g. polymannuronic acid, or alginic acid), D-glucosamine, D-galactosamine, D-glucose and neuraminic acid including homopolysaccharides and heteropolysaccharides such as lactose, amylopectin, starch, hydroxyethyl starch, amylose, dextrane sulfate, dextran, dextrins, glycogen, or the polysaccharide subunit of acid mucopolysaccharides, e.g. hyaluronic acid; polymers of sugar alcohols such as polysorbitol and polymannitol; heparin or heparon. The polymer prior to cross-linking need not be, but preferably is, water soluble, but the final conjugate must be water soluble. In addition, the polymer should not be highly immunogenic in the conjugate form, nor should it possess viscosity that is incompatible with intravenous infusion or injection if it is intended to be administered by such routes. Preferably the polymer contains only a single group which is reactive. This helps to avoid cross-linking of protein molecules. However, it is within the scope herein to optimize reaction conditions to reduce cross- linking, or to purify the reaction products through gel filtration or chromatographic sieves to recover substantially homogenous derivatives. The molecular weight ofthe polymer may desirably range from about 100 to 500,000, and preferably is from about 1,000 to 20,000. The molecular weight chosen will depend upon the nature of the polymer and the degree of substitution. In general, the greater the hydrophilicity of the polymer and the greater the degree of substitution, the lower the molecular weight that can be employed. Optimal molecular weights will be determined by routine experimentation. The polymer generally is covalently linked to the OB protein or to the OB-immunoglobulin chimera though a multifunctional crosslinking agent which reacts with the polymer and one or more amino acid or sugar residues ofthe OB protein or OB-immunoglobulin chimera to be linked. However, it is within the scope of the invention to directly crosslink the polymer by reacting a derivatized polymer with the hybrid, or via versa. The covalent crosslinking site on the OB protein or OB-immunoglobulin chimera includes the N- terminal amino group and epsilon amino groups found on lysine residues, as well as other amino, imino, carboxyl, sulfhydryl, hydroxyl or other hydrophilic groups. The polymer may be covalently bonded directly to the hybrid without the use ofa multifunctional (ordinarily bifunctional) crosslinking agent. Covalent binding to amino groups is accomplished by known chemistries based upon cyanuric chloride, carbonyl diimidazole, aldehyde reactive groups (PEG alkoxide plus diethyl acetal of bromoacetaldehyde; PEG plus DMSO and acetic anhydride, or PEG chloride plus the phenoxide of 4-hydroxybenzaldehyde, succinimidyl active esters, activated dithiocarbonate PEG, 2,4,5-trichlorophenylcloroformate or P-nitrophenylcloroformate activated PEG). Carboxyl groups are derivatized by coupling PEG-amine using carbodiimide. Polymers are conjugated to oligosaccharide groups by oxidation using chemicals, e.g. metaperiodate, or enzymes, e.g. glucose or galactose oxidase (either of which produces the aldehyde derivative of the carbohydrate), followed by reaction with hydrazide or amino derivatized polymers, in the same fashion as is described by Heitzmann et al, P.N.A.S. 71 :3537-41 (1974) or Bayer et al, Methods in Enzymology 62:310 ( 1979), for the labeling of oligosaccharides with biotin or avidin. Further, otiier chemical or enzymatic methods which have been used heretofore to link oligosaccharides are particularly advantageous because, in general, there are fewer substitutions than amino acid sites for derivatization, and the oligosaccharide products thus will be more homogenous. The oligosaccharide substituents also are optionally modified by enzyme digestion to remove sugars, e.g. by neuraminidase digestion, prior to polymer derivatization. The polymer will bear a group which is directly reactive with an amino acid side chain, or the N- or C- terminus ofthe polypeptide linked, or which is reactive with the multifunctional cross-linking agent. In general, polymers bearing such reactive groups are known for the preparation of immobilized proteins. In order to use such chemistries here, one should employ a water soluble polymer otherwise derivatized in the same fashion as insoluble polymers heretofore employed for protein immobilization. Cyanogen bromide activation is a particularly useful procedure to employ in crosslinking polysaccharides. "Water soluble" in reference to the starting polymer means that the polymer or its reactive intermediate used for conjugation is sufficiently water soluble to participate in a derivatization reaction. "Water soluble" in reference to the polymer conjugate means that the conjugate is soluble in physiological fluids such as blood. The degree of substitution with such a polymer will vary depending upon the number of reactive sites on the protein, whether all or a fragment ofthe protein is used, whether me protein is a fusion with a heterologous protein (e.g. an OB-immunoglobulin chimera), the molecular weight, hydrophilicity and other characteristics ofthe polymer, and the particular protein derivatization sites chosen. In general, the conjugate contains about from 1 to 10 polymer molecules, while any heterologous sequence may be substituted with an essentially unlimited number of polymer molecules so long as the desired activity is not significantly adversely affected. The optimal degree of cross-linking is easily determined by an experimental matrix in which the time, temperature and other reaction conditions are varied to change the degree of substitution, after which the ability of the conjugates to function in the desired fashion is determined. The polymer, e.g. PEG, is cross-linked by a wide variety of methods known per se for the covalent modification of proteins with nonproteinaceous polymers such as PEG. Certain of these methods, however, are not preferred for the puφoses herein. Cyanuronic chloride chemistry leads to many side reactions, including protein cross-linking. In addition, it may be particularly likely to lead to inactivation of proteins containing sulfhydryl groups. Carbonyl diimidazole chemistry (Beauchamp et al, Anal Biochem. 131 :25-33 (1983)) requires high pH (>8.5), which can inactivate proteins. Moreover, since the "activated PEG" intermediate can react with water, a very large molar excess of "activated PEG" over protein is required. The high concentrations of PEG required for the carbonyl diimidazole chemistry also led to problems in purification, as both gel filtration chromatography and hydrophilic interaction chromatography are adversely affected. In addition, the high concentrations of "activated PEG" may precipitate protein, a problem that per se has been noted previously (Davis, U.S. Patent No. 4, 179,337). On the other hand, aldehyde chemistry (Royer, U.S. Patent No. 4,002,531 ) is more efficient since it requires only a 40-fold molar excess of PEG and a 1-2 hr incubation. However, the manganese dioxide suggested by Royer for preparation of the PEG aldehyde is problematic "because of the pronounced tendency of PEG to form complexes with metal-based oxidizing agents" (Harris et al, J. Polym. Sci. Polym. Chem. Ed. 22:341 -52 ( 1 84)). The use of a Moffatt oxidation, utilizing DMSO and acetic anhydride, obviates this problem. In addition, the sodium borohydride suggested by Royer must be used at high pH and has a significant tendency to reduce disulfide bonds. In contrast, sodium cyanoborohydride, which is effective at neutral pH and has very little tendency to reduce disulfide bonds is preferred. Functionalized PEG polymers to modify the OB protein or OB-immunoglobulin chimeras ofthe present invention are available from Shearwater Polymers, Inc. (Huntsville, AL). Such commercially available PEG derivatives include, but are not limited to, amino-PEG, PEG amino acid esters, PEG-hydrazide, PEG-thiol, PEG- succinate, carboxymethylated PEG, PEG-propionic acid, PEG amino acids, PEG succinimidyl succinate, PEG succinimidyl propionate, succinimidyl ester of carboxymethylated PEG, succinimidyl carbonate of PEG, succinimidyl esters of amino acid PEGs, PEG-oxycarbonylimidazole, PEG-nitrophenyl carbonate, PEG tresylate, PEG-glycidyl ether, PEG-aldehyde, PEG vinylsulfone, PEG-maleimide, PEG-orthopyπdyl-disulfide, heterofunctional PEGs, PEG vinyl derivatives, PEG silanes, and PEG phospho des The reaction conditions for coupling these PEG derivatives will vary depending on the protein, the desired degree of PEGylation, and the PEG derivative utilized Some factors involved in the choice of PEG derivatives include the desired point of attachment (lysine or cysteine), hydrolytic stability and reactivity ofthe derivatives, stability, toxicity and antigenicity of the linkage, suitability for analysis, etc Specific instructions for the use of any particular derivative are available from the manufacturer The long half-life conjugates of this invention are separated from the unreacted starting materials by gel filtration Heterologous species ofthe conjugates are purified from one another in the same fashion The polymer also may be water-insoluble, as a hydrophilic gel The conjugates may also be purified by ion-exchange chromatography The chemistry of many of the electrophi cally activated PEG's results in a reduction of amino group charge ofthe PEGylated product Thus, high resolution ion exchange chromatography can be used to separate the free and conjugated proteins, and to resolve species with different levels of PEGylation In fact, the resolution of different species (e g containing one or two PEG residues) is also possible due to the difference in the ionic properties ofthe unreacted am o acids B. Therapeutic Uses for the WSX Receptor The WSX receptor and WSX receptor gene are believed to find therapeutic use for administration to a mammal in the treatment of diseases characterized by a decrease in hematopoietic cells Examples of these diseases include anemia (including macrocytic and aplastic anemia), thrombocytopenia, hypoplasia, disseminated mtravascular coagulation (DIC), myelodysplasia, immune (autoimmune) thrombocytopenic puφura (ITP), and HIV induced ITP Additionally, these WSX receptor molecules may be useful in treating myeloproliferative thrombocytotic diseases as well as thrombocytosis from inflammatory conditions and in iron deficiency WSX receptor polypeptide and WSX receptor gene which lead to an increase in hematopoietic cell proliferation may also be used to enhance repopulation of mature blood cell lineages in cells having undergone che o- or radiation therapy or bone marrow transplantation therapy Generally, the WSX receptor molecules are expected to lead to an enhancement of the proliferation and/or differentiation (but especially proliferation) of primitive hematopoietic cells Other potential therapeutic applications for WSX receptor and WSX receptor gene include the treatment of obesity and diabetes and for promoting kidney, liver and lung growth and/or repair (e g in renal failure) WSX receptor can also be used to treat obesity-related conditions, such as type II adult onset diabetes, infertility, hypercholesterolemia, hyperhpidemia, cardiovascular disease and hypertension The WSX receptor may be administered alone or in combination with cytokines (such as OB protein), growth factors or antibodies in the above-identified clinical situations This may facilitate an effective lowering ofthe dose of WSX receptor Suitable dosages for such additional molecules will be discussed below Administration of WSX receptor to a mammal having depressed levels of endogenous WSX receptor or a defective WSX receptor gene is contemplated, preferably in the situation where such depressed levels lead to a pathological disorder, or where there is lack of activation ofthe WSX receptor In these embodiments where the full length WSX receptor is to be administered to the patient, it is contemplated that the gene encoding the receptor may be administered to the patient via gene therapy technology In gene therapy applications, genes are introduced into cells in order to achieve in vivo synthesis of a therapeutically effective genetic product, for example for replacement of a defective gene. "Gene therapy" includes both conventional gene therapy where a lasting effect is achieved by a single treatment, and the administration of gene therapeutic agents, which involves the one time or repeated administration of a therapeutically effective DNA or mRNA. Antisense RNAs and DNAs can be used as therapeutic agents for blocking the expression of certain genes in vivo. It has already been shown that short antisense oligonucleotides can be imported into cells where they act as inhibitors, despite their low intracellular concentrations caused by their restricted uptake by the cell membrane. (Zamecnik et al, Proc. Natl. Acad. Sci. USA, 83:4143-4146 (1986)). The oligonucleotides can be modified to enhance their uptake, e.g. , by substituting their negatively charged phosphodiester groups by uncharged groups. There are a variety of techniques available for introducing nucleic acids into viable cells. The techniques vary depending upon whether the nucleic acid is transferred into cultured cells in vitro, or in vivo in the cells ofthe intended host. Techniques suitable for the transfer of nucleic acid into mammalian cells in vitro include the use of liposomes, electroporation, microinjection, cell fusion, DEAE-dextran, the calcium phosphate precipitation method, etc. The currently preferred in vivo gene transfer techniques include transfection with viral (typically retroviral) vectors and viral coat protein-liposome mediated transfection (Dzau et al. Trends in Biotechnology 1 1 :205-210 (1993)). In some situations it is desirable to provide the nucleic acid source with an agent that targets the target cells, such as an antibody specific for a cell surface membrane protein or the target cell, a ligand for a receptor on the target cell, etc. Where liposomes are employed, proteins which bind to a cell surface membrane protein associated with endocytosis may be used for targeting and/or to facilitate uptake, e.g. capsid proteins or fragments thereof tropic for a particular cell type, antibodies for proteins which undergo internalization in cycling, and proteins that target intracellular localization and enhance intracellular half-life. The technique of receptor-mediated endocytosis is described, for example, by Wu et al, J. Biol. Chem. 262:4429-4432 (1987); and Wagner et al, Proc. Natl Acad. Sci. USA 87:3410-3414 (1990). For review of the currently known gene marking and gene therapy protocols see Anderson et al. , Science 256:808-813 ( 1992). The invention also provides antagonists of WSX receptor activation (e.g. WSX receptor ECD, WSX receptor immunoadhesins and WSX receptor antisense nucleic acid; neutralizing antibodies and uses thereof are discussed in section E below). Administration of WSX receptor antagonist to a mammal having increased or excessive levels of endogenous WSX receptor activation is contemplated, preferably in the situation where such levels of WSX receptor activation lead to a pathological disorder. In one embodiment, WSX receptor antagonist molecules may be used to bind endogenous ligand in the body, thereby causing desensitized WSX receptors to become responsive to WSX ligand, especially when the levels of WSX ligand in the serum exceed normal physiological levels. Also, it may be beneficial to bind endogenous WSX ligand which is activating undesired cellular responses (such as proliferation of tumor cells). Potential therapeutic applications for WSX antagonists include for example, treatment of metabolic disorders (e.g., anorexia, cachexia, steroid-induced truncalobesity and other wasting diseases characterized by loss of appetite, diminished food intake or body weight loss), stem cell tumors and other tumors which express WSX receptor. Pharmaceutical compositions ofthe WSX receptor ECD may further include a WSX ligand. Such dual compositions may be beneficial where it is therapeutically useful to prolong half-life of WSX ligand, and/or activate endogenous WSX receptor directly as a heterotrimeric complex. Therapeutic formulations of WSX receptor are prepared for storage by mixing WSX receptor having the desired degree of purity with optional physiologically acceptable carriers, excipients, or stabilizers (Remington's Pharmaceutical Sciences, 16th edition, Osol, A., Ed., (1980)), in the form of lyophilized cake or aqueous solutions. Acceptable carriers, excipients, or stabilizers are nontoxic to recipients at the dosages and concentrations employed, and include buffers such as phosphate, citrate, and other organic acids; antioxidants including ascorbic acid; low molecular weight (less than about 10 residues) polypeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, giutamine, asparagine, arginine, or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; salt-forming counter-ions such as sodium; and or non-ionic surfactants such as Tween, Pluronics™ or polyethylene glycol (PEG). The WSX receptor also may be entrapped in microcapsules prepared, for example, by coacervation techniques or by interfacial polymerization (for example, hydroxymethylcellulose or gelatin-microcapsules and poly-(methylmethacylate) microcapsules, respectively), in colloidal drug delivery systems (for example, liposomes, albumin microspheres, microemulsions, nano-particles, and nanocapsules), or in macroemulsions. Such techniques are disclosed in Remington's Pharmaceutical Sciences, supra. WSX receptor to be used for in vivo administration must be sterile. This is readily accomplished by filtration through sterile filtration membranes, prior to or following lyophilization and reconstitution. WSX receptor ordinarily will be stored in lyophilized form or in solution. Therapeutic WSX receptor compositions generally are placed into a container having a sterile access port, for example, an intravenous solution bag or vial having a stopper pierceable by a hypodermic injection needle. The route of WSX receptor administration is in accord with known methods, e.g., those routes set forth above for specific indications, as well as the general routes of injection or infusion by intravenous, intraperitoneal, intracerebral, intramuscular, intraocular, intraarterial, or intralesional means, or sustained release systems as noted below. WSX receptor is administered continuously by infusion or by bolus injection. Generally, where the disorder permits, one should formulate and dose the WSX receptor for site-specific delivery. Suitable examples of sustained-release preparations include semipermeable matrices of solid hydrophobic polymers containing the protein, which matrices are in the form of shaped articles, e.g., films, or microcapsules. Examples of sustained-release matrices include polyesters, hydrogels (e.g., poly(2-hydroxyethyl- methacrylate) as described by hanger etal, J. Biomed. Mater. Res. 15:167-277 (1981) and Laπger, Chem. Tech. 12:98-105 (1982) or poly(vinylalcohol)), polylactides (U.S. Patent No. 3,773,919, EP 58,481), copolymers of L-glutamic acid and γ ethyl-L-glutamate (Sidman et al, Biopolymers 22:547-556 (1983)), non-degradable ethylene-vinyl acetate (Langer et al, supra), degradable lactic acid-glycolic acid copolymers such as the Lupron Depot (injectable microspheres composed of lactic acid-glycolic acid copolymer and leuprolide acetate), and poly-D-(-)-3-hydroxybutyric acid (EP 133,988). While polymers such as ethylene-vinyl acetate and lactic acid-glycolic acid enable release of molecules for over 100 days, certain hydrogels release proteins for shorter time periods. When encapsulated proteins remain in the body for a long time, they may denature or aggregate as a result of exposure to moisture at 37° C, resulting in a loss of biological activity and possible changes in immunogenicity. Rational strategies can be devised for protein stabilization depending on the mechanism involved. For example, if the aggregation mechanism is discovered to be intermolecular S-S bond formation through thio-disulfide interchange, stabilization may be achieved by modifying sulfhydryl residues, lyophilizing from acidic solutions, controlling moisture content, using appropriate additives, and developing specific polymer matrix compositions. Sustained-release WSX receptor compositions also include liposomal ly entrapped WSX receptor. Liposomes containing WSX receptor are prepared by methods known per se: DE 3 ,218, 121 ; Epstein et al. , Proc. Natl. Acad. Sci. USA 82:3688-3692 (1985); Hwang et al, Proc. Natl. Acad. Sci. USA 77:4030-4034 ( 1980); EP 52,322; EP 36,676; EP 88,046; EP 143,949; EP 142,641 ; Japanese patent application 83-1 18008; U.S. Patent Nos. 4,485,045 and 4,544,545; and EP 102,324. Ordinarily the liposomes are o the small (about 200-800 Angstroms) unilamellar type in which the lipid content is greater than about 30 mol. % cholesterol, the selected proportion being adjusted for the optimal WSX receptor therapy. When applied topically, the WSX receptor is suitably combined with omer ingredients, such as carriers and/or adjuvants. There are no limitations on the nature of such other ingredients, except that they must be physiologically acceptable and efficacious for their intended administration, and cannot degrade the activity of the active ingredients of the composition. Examples of suitable vehicles include ointments, creams, gels, or suspensions, with or without purified collagen. The compositions also may be impregnated into transdermal patches, plasters, and bandages, preferably in liquid or semi-liquid form. For obtaining a gel formulation, the WSX receptor formulated in a liquid composition may be mixed with an effective amount ofa water-soluble polysaccharide or synthetic polymer such as PEG to form a gel of the proper viscosity to be applied topically. The polysaccharide that may be used includes, for example, cellulose derivatives such as etherified cellulose derivatives, including alkyl celluloses, hydroxyalkyl celluloses, and alkylhydroxyalkyl celluloses, for example, methylcellulose, hydroxyethyl cellulose, carboxymethyl cellulose, hydroxypropyl methylcellulose, and hydroxypropyl cellulose; starch and fractionated starch; agar; alginic acid and alginates; gum arabic; pullullan; agarose; carrageenan; dextrans; dextrins; fructans; inulin; mannans; xylans; arabinans; chitosans; glycogens; glucans; and synthetic biopolymers; as well as gums such as xanthan gum; guar gum; locust bean gum; gum arabic; tragacanth gum; and karaya gum; and derivatives and mixtures thereof. The preferred gelling agent herein is one that is inert to biological systems, nontoxic, simple to prepare, and not too runny or viscous, and will not destabilize the WSX receptor held within it. Preferably the polysaccharide is an etherified cellulose derivative, more preferably one that is well defined, purified, and listed in USP, e.g., methylcellulose and the hydroxyalkyl cellulose derivatives, such as hydroxypropyl cellulose, hydroxyethyl cellulose, and hydroxypropyl methylcellulose. Most preferred herein is methylcellulose. The polyethylene glycol useful for gelling is typically a mixture of low and high molecular weight PEGs to obtain the proper viscosity. For example, a mixture of a PEG of molecular weight 400-600 with one of molecular weight 1500 would be effective for this puφose when mixed in the proper ratio to obtain a paste. The term "water soluble" as applied to the polysaccharides and PEGs is meant to include colloidal solutions and dispersions. In general, the solubility ofthe cellulose derivatives is determined by the degree of substitution of ether groups, and the stabilizing derivatives useful herein should have a sufficient quantity of such ether groups per anhydroglucose unit in the cellulose chain to render the derivatives water soluble. A degree of ether substitution of at least 0.35 ether groups per anhydroglucose unit is generally sufficient. Additionally, the cellulose derivatives may be in the form of alkali metal salts, for example, the Li, Na, K, or Cs salts. If methylcellulose is employed in the gel, preferably it comprises about 2-5%, more preferably about 3%, of the gel and the WSX receptor is present in an amount of about 300-1000 mg per ml of gel. An effective amount of WSX receptor to be employed therapeutically will depend, for example, upon the therapeutic objectives, the route of administration, and the condition ofthe patient. Accordingly, it will be necessary for the therapist to titer the dosage and modify the route of administration as required to obtain the optimal therapeutic effect. Typically, the clinician will administer the WSX receptor until a dosage is reached mat achieves the desired effect. A typical daily dosage for systemic treatment might range from about 1 μg/kg to up to 10 mg/kg or more, depending on the factors mentioned above. As an alternative general proposition, the WSX receptor is formulated and delivered to the target site or tissue at a dosage capable of establishing in the tissue a WSX receptor level greater than about 0.1 ng cc up to a maximum dose that is efficacious but not unduly toxic. This intra-tissue concentration should be maintained if possible by continuous infusion, sustained release, topical application, or injection at empirically determined frequencies. The progress of this therapy is easily monitored by conventional assays. C. Non-Therapeutic Uses for the WSX Receptor WSX receptor nucleic acid is useful for the preparation of WSX receptor polypeptide by reco binant techniques exemplified herein which can then be used for production of anti-WSX receptor antibodies having various utilities described below. The WSX receptor (polypeptide or nucleic acid) can be used to induce proliferation and/or differentiation of cells in vitro. In particular, it is contemplated that this molecule may be used to induce proliferation of stem cell progenitor cell populations (e.g. CD34+ cell populations obtained as described in Example 8 below). These cells which are to be grown ex vivo may simultaneously be exposed to other known growth factors or cytokines, such as those described herein. This results in proliferation and/or differentiation ofthe cells having the WSX receptor. In yet another aspect ofthe invention, the WSX receptor may be used for affinity purification of WSX ligand. Briefly, this technique involves: (a) contacting a source of WSX ligand with an immobilized WSX receptor under conditions whereby the WSX ligand to be purified is selectively adsorbed onto the immobilized receptor; (b) washing the immobilized WSX receptor and its support to remove non-adsorbed material; and (c) eluting the WSX ligand molecules from the immobilized WSX receptor to which they are adsorbed with an elution buffer. In a particularly preferred embodiment of affinity purification, WSX receptor is covalently attaching to an inert and porous matrix (e.g., agarose reacted with cyanogen bromide). Especially preferred is a WSX receptor immunoadhesin immobilized on a protein A column. A solution containing WSX ligand is then passed through the chromatographic material. The WSX ligand adsorbs to the column and is subsequently released by changing the elution conditions (e.g. by changing pH or ionic strength). The WSX receptor may be used for competitive screening of potential agonists or antagonists for binding to the WSX receptor. Such agonists or antagonists may constitute potential therapeutics for treating conditions characterized by insufficient or excessive WSX receptor activation, respectively. The preferred technique for identifying molecules which bind to the WSX receptor utilizes a chimeric receptor (e.g., epitope tagged WSX receptor or WSX receptor immunoadhesin) attached to a solid phase, such as the well of an assay plate. Binding of molecules which are optionally labelled (e.g., radiolabelled) to the immobilized receptor can be evaluated. To identify WSX receptor agonists or antagonists, the thymidine incoφoration assay can be used. For screening for antagonists, the WSX receptor can be exposed to a WSX ligand followed by the putative antagonist, or the WSX ligand and antagonist can be added to the WSX receptor simultaneously, and the ability of the antagonist to block receptor activation can be evaluated. The WSX receptor polypeptides are also useful as molecular weight markers. To use a WSX receptor polypeptide as a molecular weight marker, gel filtration chromatography or SDS-PAGE, for example, will be used to separate protein(s) for which it is desired to determine their molecular weight(s) in substantially the normal way. The WSX receptor and other molecular weight markers will be used as standards to provide a range of molecular weights. For example, phosphorylase b (mw = 97,400), bovine serum albumin (mw = 68,000), ovalbumin (mw = 46,000), WSX receptor (mw = 44,800), trypsin inhibitor (mw = 20,100), and lysozyme (mw = 14,400) can be used as mw markers. The other molecular weight markers mentioned here can be purchased commercially from Amersham Coφoration, Arlington Heights, IL. The molecular weight markers are generally labeled to facilitate detection thereof. For example, the markers may be biotinylated and following separation can be incubated with streptavidin-horseradish peroxidase so that the various markers can be detected by light detection. The purified WSX receptor, and the nucleic acid encoding it, may also be sold as reagents for mechanism studies of WSX receptor and its ligands, to study the role of the WSX receptor and WSX ligand in normal growth and development, as well as abnormal growth and development, e.g., in malignancies. WSX receptor variants are useful as standards or controls in assays for the WSX receptor for example ELISA, RIA, or RRA, provided that they are recognized by the analytical system employed, e.g. , an anti-WSX receptor antibody. D. WSX Receptor Antibody Preparation 1. Polyclonal antibodies Polyclonal antibodies are generally raised in animals by multiple subcutaneous (sc) or intraperitoneal (ip) injections ofthe relevant antigen and an adjuvant. In that the preferred epitope is in the ECD ofthe WSX receptor, it is desirable to use WSX receptor ECD or a molecule comprising the ECD (e.g. , WSX receptor immunoadhesin) as the antigen for generation of polyclonal and monoclonal antibodies. It may be useful to conjugate the relevant antigen to a protein that is immunogenic in the species to be immunized, e.g., keyhole limpet hemocyanin, serum albumin, bovine thyroglobulin, or soybean trypsin inhibitor using a bifunctional or derivatizing agent, for example, maleimidobenzoyl sulfosuccinimide ester (conjugation through cysteine residues), N-hydroxysuccinimide (through lysine residues), glutaraldehyde, succinic anhydride, SOCI 2 , or R 1 N=C=NR, where R and R are different alkyl groups. Animals are immunized against the antigen, immunogenic conjugates, or derivatives by combining 1 mg or 1 μg ofthe peptide or conjugate (for rabbits or mice, respectively) with 3 volumes of Freund's complete adjuvant and injecting the solution intradermally at multiple sites. One month later the animals are boosted with 1/5 to 1/lO the original amount of peptide or conjugate in Freund's complete adjuvant by subcutaneous injection at multiple sites. Seven to 14 days later the animals are bled and the serum is assayed for antibody titer. Animals are boosted until the titer plateaus. Preferably, the animal is boosted with the conjugate ofthe same antigen, but conjugated to a different protein and/or through a different cross-linking reagent. Conjugates also can be made in recombinant cell culture as protein fusions. Also, aggregating agents such as alum are suitably used to enhance the immune response. 2. Monoclonal antibodies Monoclonal antibodies are obtained from a population of substantially homogeneous antibodies, i.e., the individual antibodies comprising the population are identical except for possible naturally occurring mutations that may be present in minor amounts. Thus, the modifier "monoclonal" indicates the character ofthe antibody as not being a mixture of discrete antibodies. For example, the monoclonal antibodies may be made using the hybridoma method first described by Kohler et al, Nature 256:495 (1975), or may be made by recombinant DNA methods (Cabilly el al, supra). In the hybridoma method, a mouse or other appropriate host animal, such as a hamster, is immunized as hereinabove described to elicit lymphocytes that produce or are capable of producing antibodies that will specifically bind to the protein used for immunization. Alternatively, lymphocytes may be immunized in vitro. Lymphocytes then are fused with myeloma cells using a suitable fusing agent, such as polyethylene glycol, to form a hybridoma cell (Goding, Monoclonal Antibodies: Principles and Practice, pp. 9- 103 (Academic Press, 1986)). The hybridoma cells thus prepared are seeded and grown in a suitable culture medium that preferably contains one or more substances mat inhibit the growth or survival ofthe unfused, parental myeloma cells. For example, if the parental myeloma cells lack the enzyme hypoxanthine guanine phosphoribosyl transferase (HGPRT or HPRT), the culture medium for the hybridomas typically will include hypoxanthine, aminopterin, and thymidine (HAT medium), which substances prevent the growth of HGPRT-deficient cells. Preferred myeloma cells are those that fuse efficiently, support stable high-level production of antibody by the selected antibody-producing cells, and are sensitive to a medium such as HAT medium. Among these, preferred myeloma cell lines are murine myeloma lines, such as those derived from MOPC-21 and MPC-1 1 mouse tumors available from the Salk Institute Cell Distribution Center, San Diego, California USA, and SP-2 cells available from the American Type Culture Collection, Rockville, Maryland USA. Human myeloma and mouse-human heteromyeloma cell lines also have been described for the production of human monoclonal antibodies (Kozbor, J. Immunol. 133:3001 (1984); Brodeur et al, Monoclonal Antibody Production Techniques and Applications, pp. 51-63 (Marcel Dekker, Inc., New York, 1987)). Culture medium in which hybridoma cells are growing is assayed for production of monoclonal antibodies directed against the antigen. Preferably, the binding specificity of monoclonal antibodies produced by hybridoma cells is determined by immunoprecipitation or by an in vitro binding assay, such as radioimmunoassay (RIA) or enzyme-linked immunoabsorbent assay (ELISA). The binding affinity of the monoclonal antibody can, for example, be determined by the Scatchard analysis of Munson et al, Anal. Biochem. 107:220 (1980). After hybridoma cells are identified that produce antibodies ofthe desired specificity, affinity, and/or activity, the clones may be subcloned by limiting dilution procedures and grown by standard methods (Goding, supra). Suitable culture media for this puφose include, for example, D-MEM or RPMI- 1640 medium. In addition, the hybridoma cells may be grown in vivo as ascites tumors in an animal. The monoclonal antibodies secreted by the subclones are suitably separated from the culture medium, ascites fluid, or serum by conventional immunoglobulin purification procedures such as, for example, protein A-Sepharose, hydroxylapatite chromatography, gel electrophoresis, dialysis, or affinity chromatography. DNA encoding the monoclonal antibodies is readily isolated and sequenced using conventional procedures (e.g., by using oligonucleotide probes that are capable of binding specifically to genes encoding the heavy and light chains of murine antibodies). The hybridoma cells serve as a preferred source of such DNA. Once isolated, the DNA may be placed into expression vectors, which are then transfected into host cells such as E. coli cells, simian COS cells, Chinese hamster ovary (CHO) cells, or myeloma cells that do not otherwise produce immunoglobulin protein, to obtain the synthesis of monoclonal antibodies in the recombinant host cells. Review articles on recombinant expression in bacteria of DNA encoding the antibody include Skerra et al, Curr. Opinion in Immunol 5:256-262 (1993) and Plϋckthun, Immunol Revs. 130: 151-188 (1992). In a further embodiment, antibodies or antibody fragments can be isolated from antibody phage libraries generated using the techniques described in McCafferty et al, Nature 348:552-554 (1990). Clackson et al , Nature 352:624-628 (1991) and Marks et al, J. Mol Biol. 222:581-597 (1991) describe the isolation of murine and human antibodies, respectively, using phage libraries. Subsequent publications describe the production of high affinity (nM range) human antibodies by chain shuffling (Mark et al, Bio/Technology 10:779-783 (1992)), as well as combinatorial infection and in vivo recombination as a strategy for constructing very large phage libraries (Waterhouse et al, Nuc. Acids. Res. 21:2265-2266 (1993)). Thus, these techniques are viable alternatives to traditional monoclonal antibody hybridoma techniques for isolation of monoclonal antibodies. The DNA also may be modified, for example, by substituting the coding sequence for human heavy- and light-chain constant domains in place ofthe homologous murine sequences (Cabilly et al, supra; Morrison, et al, Proc. Nat. Acad. Sci. USA 81 :6851 (1984)), or by covalently joining to the immunoglobulin coding sequence all or part of the coding sequence for a non-immunoglobulin polypeptide. Typically such non-immunoglobulin polypeptides are substituted for the constant domains of an antibody, or they are substituted for the variable domains of one antigen-combining site of an antibody to create a chimeric bivalent antibody comprising one antigen-combining site having specificity for an antigen and another antigen-combining site having specificity for a different antigen. Chimeric or hybrid antibodies also may be prepared in vitro using known methods in synthetic protein chemistry, including those involving crosslinking agents. For example, immunotoxins may be constructed using a disulfide-exchange reaction or by forming a thioether bond. Examples of suitable reagents for this puφose include iminothiolate and methyl-4-mercaptobutyrimidate. 3. Humanized and human antibodies Methods for humanizing non-human antibodies are well known in the art. Generally, a humanized antibody has one or more amino acid residues introduced into it from a source which is non-human. These non- human amino acid residues are often referred to as "import" residues, which are typically taken from an "import" variable domain. Humanization can be essentially performed following the method of Winter and co-workers (Jones et al, Nature 321 :522-525 (1986); Riechmann et al, Nature 332:323-327 (1988); Verhoeyen et al. Science 239: 1534- 1536 ( 1988)), by substituting rodent CDRs or CDR sequences for the corresponding sequences of a human antibody. Accordingly, such "humanized" antibodies are chimeric antibodies (Cabilly et al, supra), wherein substantially less than an intact human variable domain has been substituted by the corresponding sequence from a non-human species. In practice, humanized antibodies are typically human antibodies in which some CDR residues and possibly some FR residues are substituted by residues from analogous sites in rodent antibodies. The choice of human variable domains, both light and heavy, to be used in making the humanized antibodies is very important to reduce antigenicity. According to the so-called "best-fit" method, the sequence of the variable domain of a rodent antibody is screened against the entire library of known human variable- domain sequences. The human sequence which is closest to that ofthe rodent is then accepted as the human framework (FR) for the humanized antibody (Sims et al, J. Immunol. 151 :2296 ( 1993); Chothia et al, J. Mol. Biol 196:901 (1987)). Another method uses a particular framework derived from the consensus sequence of all human antibodies ofa particular subgroup of light or heavy chains. The same framework may be used for several different humanized antibodies (Carter et al , Proc. Natl. Acad. Sci. USA 89:4285 ( 1992); Presta et al. , J. lmmnol 151 :2623 (1993)). It is further important that antibodies be humanized with retention of high affinity for the antigen and other favorable biological properties. To achieve this goal, according to a preferred method, humanized antibodies are prepared by a process of analysis ofthe parental sequences and various conceptual humanized products using three-dimensional models of the parental and humanized sequences. Three-dimensional immunoglobulin models are commonly available and are familiar to those skilled in the art. Computer programs are available which illustrate and display probable three-dimensional conformational structures of selected candidate immunoglobulin sequences. Inspection of these displays permits analysis ofthe likely role ofthe residues in the functioning ofthe candidate immunoglobulin sequence, i.e., the analysis of residues that influence the ability of the candidate immunoglobulin to bind its antigen. In this way, FR residues can be selected and combined from the consensus and import sequences so that the desired antibody characteristic, such as increased affinity for the target antigen(s), is achieved. In general, the CDR residues are directly and most substantially involved in influencing antigen binding. Alternatively, it is now possible to produce transgenic animals (e.g., mice) that are capable, upon immunization, of producing a full repertoire of human antibodies in the absence of endogenous immunoglobulin production. For example, it has been described that the homozygous deletion ofthe antibody heavy-chain joining region (Jp j ) gene in chimeric and germ-line mutant mice results in complete inhibition of endogenous antibody production. Transfer ofthe human germ-line immunoglobulin gene array in such germ-line mutant mice will result in the production of human antibodies upon antigen challenge. See, e.g., Jakobovits et al, Proc. Natl Acad. Sci USA 90:2551 (1993); Jakobovits et al, Nature 362:255-258 ( 1993); Bruggermann et al. Year in Immuno. 7:33 (1993). Human antibodies can also be produced in phage- display libraries (Hoogenboom et al , J. Mol. Biol 227:381 (1991 ); Marks et al., J. Mol. β/ø/.222:581 (1991)). 4. Bispecific antibodies Bispecific antibodies (BsAbs) are antibodies that have binding specificities for at least two different antigens. BsAbs can be used as tumor targeting or imaging agents and can be used to target enzymes or toxins to a cell possessing the WSX receptor. Such antibodies can be derived from full length antibodies or antibody fragments (e.g. F(ab' 2 bispecific antibodies). In accordance with the present invention, the BsAb may possess one arm which binds the WSX receptor and another arm which binds to a cytokine or another cytokine receptor (or a subunit thereof) such as the receptors for TPO, EPO, G-CSF, IL-4, IL-7, GH, PRL; the α or β subunits of the IL-3, GM-CSF, IL-5, IL-6, LIF, OSM and CNTF receptors; or the α, β or γ subunits ofthe IL-2 receptor complex. For example, the BsAb may bind both WSX receptor and gpl30. Methods for making bispecific antibodies are known in the art. Traditional production of full length bispecific antibodies is based on the coexpression of two immunoglobulin heavy chain-light chain pairs, where the two chains have different specificities (Millstein et al, Nature 305:537-539 (1983)). Because ofthe random assortment of immunoglobulin heavy and light chains, these hybridomas (quadromas) produce a potential mixture of 10 different antibody molecules, of which only one has the correct bispecific structure. Purification of the correct molecule, which is usually done by affinity chromatography steps, is rather cumbersome, and the product yields are low. Similar procedures are disclosed in WO 93/08829, published 13 May 1993, and in Traunecker et al, EMBO J. 10:3655-3659 (1991). According to a different and more preferred approach, antibody variable domains with the desired binding specificities (antibody-antigen combining sites) are fused to immunoglobulin constant domain sequences. The fusion preferably is wi an immunoglobulin heavy chain constant domain, comprising at least part ofthe hinge, CH2, and CH3 regions. It is preferred to have the first heavy-chain constant region (CH 1 ) containing the site necessary for light chain binding, present in at least one of me fusions. DNAs encoding the immunoglobulin heavy chain fusions and, if desired, the immunoglobulin light chain, are inserted into separate expression vectors, and are co-transfected into a suitable host organism. This provides for great flexibility in adjusting the mutual proportions ofthe three polypeptide fragments in embodiments when unequal ratios ofthe three polypeptide chains used in the construction provide the optimum yields. It is, however, possible to insert the coding sequences for two or all three polypeptide chains in one expression vector when the expression of at least two polypeptide chains in equal ratios results in high yields or when the ratios are of no particular significance. In a preferred embodiment of this approach, the bispecific antibodies are composed of a hybrid immunoglobulin heavy chain with a first binding specificity in one arm, and a hybrid immunoglobulin heavy chain-light chain pair (providing a second binding specificity) in the other arm. It was found that this asymmetric structure facilitates the separation ofthe desired bispecific compound from unwanted immunoglobulin chain combinations, as the presence of an immunoglobulin light chain in only one half of the bispecific molecule provides for a facile way of separation. This approach is disclosed in WO 94/04690 published March 3, 1994. For further details of generating bispecific antibodies see, for example, Suresh et al. , Methods in Enzymology 121 :210 (1986). Bispecific antibodies include cross-linked or "heteroconjugate" antibodies. For example, one of the antibodies in the heteroconjugate can be coupled to avidin, the other to biotin. Such antibodies have, for example, been proposed to target immune system cells to unwanted cells (US Patent No. 4,676,980), and for treatment of HIV infection (WO 91/00360, WO 92/200373, and EP 03089). Heteroconjugate antibodies may be made using any convenient cross-linking methods. Suitable cross-linking agents are well known in the art, and are disclosed in US Patent No. 4,676,980, along with a number of cross-linking techniques. Techniques for generating bispecific antibodies from antibody fragments have also been described in the literature. The following techniques can also be used for the production of bivalent antibody fragments which are not necessarily bispecific. According to these techniques, Fab'-SH fragments can be recovered from E. coli, which can be chemically coupled to form bivalent antibodies. Shalaby ef α/., J. Exp. Med. 175:217-225 (1992) describe the production of a fully humanized BsAb F(ab' 2 molecule. Each Fab' fragment was separately secreted from E. coli and subjected to directed chemical coupling in vitro to form the BsAb. The BsAb thus formed was able to bind to cells overexpressing the HER2 receptor and normal human T cells, as well as trigger me lytic activity of human cytotoxic lymphocytes against human breast tumor targets. See also Rodrigues et al, Int. J. Cancers (Suppl.) 7:45-50 (1992). Various techniques for making and isolating bivalent antibody fragments directly from recombinant cell culture have also been described. For example, bivalent heterodimers have been produced using leucine zippers. Kostelny et al, J. Immunol. 148(5): 1547- 1553 (1992). The leucine zipper peptides from the Fos and Jun proteins were linked to the Fab' portions of two different antibodies by gene fusion. The antibody homodimers were reduced at the hinge region to form monomers and then re-oxidized to form the antibody heterodimers. The "diabody" technology described by Hollinger et al, Proc. Natl Acad. Sci. USA 90:6444-6448 (1993) has provided an alternative mechanism for making BsAb fragments. The fragments comprise a heavy-chain variable domain (Vu) connected to a light-chain variable domain (Vi ) by a linker which is too short to allow pairing between the two domains on the same chain. Accordingly, the VJ_J and V^ domains of one fragment are forced to pair with the complementary V L and V j _τ domains of another fragment, thereby forming two antigen-binding sites. Another strategy for making BsAb fragments by the use of single-chain Fv (sFv) dimers has also been reported. See Gruber et al. , J. Immunol. 152:5368 (1994). 5. Antibody Screening It may be desirable to select antibodies with a strong binding affinity for the WSX receptor. Antibody affinities may be determined by saturation binding; enzyme-linked immunoabsorbent assay (ELISA); and competition assays (e.g. RIA's), for example. The antibody with a strong binding affinity may bind the WSX receptor with a binding affinity (K^) value of no more than about 1 x 10 " ' M, preferably no more than about 1 x IO "8 M and most preferably no more than about 1 x 10 " * M (e.g. to about 1 x 10 " J2 M). In another embodiment, one may screen for an antibody which binds a WSX receptor epitope of interest. For example, an antibody which binds to the epitope bound by antibody 2D7, 1 G4, I E 1 1 or 1 C 1 1 (see Example 13) or antibody clone #3, #4 or #17 (see Example 14) can be identified. To screen for antibodies which bind to the epitope on WSX receptor bound by an antibody of interest (e.g., those which block binding of any one ofthe above antibodies to WSX receptor), a routine cross-blocking assay such as that described in Antibodies A Laboratory Manual, Cold Spring Harbor Laboratory, Ed Harlow and David Lane (1988), can be performed Alternatively, epitope mapping, e g as described in Champe et al , J Biol Chem 270 1388- 1 94 ( 1995), can be performed to determine whether the antibody binds an epitope of interest In one particularly preferred embodiment ofthe invention, agonist antibodies are selected Various methods for selecting agonist antibodies are available In one embodiment, one evaluates the agonistic properties ofthe antibody upon binding to a chimeric receptor comprising the WSX receptor extracellular domain in an assay called the kinase receptor activation enzyme linked immunoadsorbent assay (KIRA ELISA) described in WO95/14930 (expressly incoφorated herein by reference) To perform the KIRA ELISA, a chimeric receptor comprising the extracellular domain ofthe WSX receptor and the transmembrane and intracellular domain of Rse receptor (Mark et al , Journal of Biological Chemistry 269(14) 10720-10728 (1994)) with a carboxyl-terminal heφes simplex virus glycoprotein D (gD) tag is produced and dpl2 CHO cells are transformed therewith as described in Example 4 of WO95/14930 4 The WSX/Rse gD transformed dpi 2 CHO cells are seeded (3x10 per well) in the wells of a flat- bottom-96 well culture plate in lOOμl media and cultured overnight at 37° C in 5% CO^ The following morning the well supernatants are removed and various concentrations of the antibody are added to separate wells The cells are stimulated at 37° C for 30 mm , the well supernatants are decanted To lyse the cells and solubilize the chimeric receptors, 100 μl of lysis buffer is added to each well The plate is then agitated gently on a plate shaker (Bellco Instruments, Vineland, NJ) for 60 min at room temperature While the cells are being solubi zed, an ELISA microtiter plate (Nunc Maxisoφ, Inter Med, Denmark) coated overnight at 4°C with the 5B6 monoclonal anti-gD antibody (5 0 μg/ml in 50 M carbonate buffer, pH 9 6, 100 μl/well) is decanted and blocked with 150 μl/well of Block Buffer for 60 mm at room temperature After 60 minutes, the anti-gD 5B6 coated plate is washed 6 times with wash buffer (PBS containing 0 05 % TWEEN 20™ and 0 01 % thimerosal) The lysate contaming solubihzed WSX/Rse gD from the cell-culture microtiter well is transferred (85μl/well) to anti-gD 5B6 coated and blocked ELISA well and is incubated for 2 h at room temperature The unbound WSX Rse gD is removed by washing with wash buffer and 100 μl of biotinylated 4G 10 (anti- phosphotyrosme) diluted 1 18000 in dilution buffer (PBS containing 0 5 % BSA, 0 05 % Tween-20, 5 mM EDTA, and 0 01 % thimerosal), / e 56 ng/ml is added to each well After incubation for 2 h at room temperature the plate is washed and HRPO-conjugated streptavidin (Zymed Laboratories, S San Francisco, CA) is added to each well The plate is incubated for 30 minutes at room temperature with gentle agitation The free avid - conjugate is washed away and 100 μl freshly prepared substrate solution (tetramethyl benzidine (TMB), 2- component substrate kit, Kirkegaard and Perry, Gaithersburg, MD) is added to each well The reaction is allowed to proceed for 10 minutes, after which the color development is stopped by the addition of lOOμl/well 1 0 M H POΛ The absorbance at 450 nm is read with a reference wavelength of 650 nm (ABS45Q 50X using a vmax plate reader (Molecular Devices, Palo Alto, CA) controlled with a Macintosh Centπs 650 (Apple Computers, Cupertino, CA) and DeltaSoft software (BioMetal cs, Inc, Princeton, NJ) Those antibodies which have an IC50 in the KIRA ELISA of about 0.5μg/ml or less (e.g. from about 0.5μg/ml to about 0.001 μg/ml), preferably about 0.2μg/ml or less and most preferably about 0.1 μg/ml or less are preferred agonists. In another embodiment, one screens for antibodies which activate downstream signaling molecules for OB protein. For example, the ability of the antibody to activate Signal Transducers and Activators of Transcription (STATs) can be assessed. The agonist antibody of interest may stimulate formation of STAT- 1 and STAT-3 complexes, for example. To screen for such antibodies, the assay described in Rosenblum et al Endocrinology 137( 1 1 ):5178-51 1 (1996) may be performed. Alternatively, an antibody which stimulates proliferation and/or differentiation of hematopoietic cells can be selected. For example, the hematopoiesis assays of Example 10 below can be performed. For example, murine fetal liver flASK stem cells may be isolated from the midgestational fetal liver as described in Zeigler et al, Blood 84:2422-2430 (1994) and studied in stem cell suspension culture or methylcellulose assays. For the stem cell suspension cultures, twenty thousand ofthe fLASK cells are seeded in individual wells in a 12 well format in DMEM 4.5/F12 media supplemented with 10% heat inactivated fetal calf serum (Hyclone, Logan, UT) and L-glutamine. Growth factors are added at the following concentrations: kit ligand (KL) at 25 ng/mL, interleukin-3 (IL-3) at 25 ng/mL, interleukin-6 (IL-6) at 50 ng/mL, G-CSF at 100 ng/mL, GM-CSF at 100 ng mL, EPO at 2U/mL, interleukin-7 (IL-7) at 100 ng/mL (all growth factors from R and D Systems, Minneapolis, MN). The agonist antibody is men added and the ability ofthe antibody to expand the flASK cells grown in suspension culture is assessed. Methylcellulose assays are performed as previously described (Zeiger et ai, supra). Briefly, methylcellulose colony assays are performed using "complete" methylcellulose or pre-B methylcellulose medium (Stem Cell Technologies, Vancouver, British Columbia, Canada) with the addition of 25 ng/mL KL (R and D Systems, Minneapolis, MN). Cytospin analyses of me resultant colonies are performed as previously described in Zeigler et al. The ability of the agonist antibody to augment myeloid, lymphoid and erythroid colony formation is assessed. Also, the effect ofthe agonist antibody on the murine bone marrow stem cell population; Lin Sca + may be evaluated. One may select an agonist antibody which induces a statistically significant decrease in body weight and/or fat-depot weight and/or food intake in an obese mammal (e.g. in an oblob mouse). Methods for screening for such molecules are described in Levin et al. Proc. Natl Acad. Sci. USA 93 : 1726- 1730 ( 1996), for example. Preferred agonist antibodies are those which exert adipose-reducing effects in an obese mammal, such as the oblob mouse, which are in excess of those induced by reductions in food intake. The antibody of interest herein may have the hypervariable region residues of one ofthe antibodies in Examples 13 and 14. Also, the invention encompasses "affinity matured" forms of these antibodies in which hypervariable region residues of mese antibodies have been modified. Such affinity matured antibodies will preferably have a biological activity which is the same as or better than that ofthe original antibody. The affinity matured antibody may have from about 1-10, e.g. 5-10 deletions, insertions or substitutions (but preferably substitutions) in the hypervariable regions thereof. One useful procedure for generating affinity matured antibodies is called "alanine scanning mutagenesis" (Cunningham and Wells Science 244: 1081 -1085 ( 1989)). Here, one or more ofthe hypervariable region residue(s) are replaced by alanine or polyalanine residue(s) to affect the interaction of the amino acids with the WSX receptor. Those hypervariable region residue(s) demonstrating functional sensitivity to substitution are then refined by introducing further or other mutations at or for the sites of substitution. The ala-mutants produced this way are screened for their biological activity as described herein. Another procedure is affinity maturation using phage display (Hawkins et al J. Mol Biol 254:889-896 (1992) and Lowman et al. Biochemistry 30(45): 10832- 10837 ( 1991)). Briefly, several hypervariable region sites (e.g. 6-7 sites) are mutated to generate all possible amino substitutions at each site. The antibody mutants thus generated are displayed in a monovalent fashion from filamentous phage particles as fusions to the gene III product of M 13 packaged within each particle. The phage-displayed mutants are then screened for their biological activity (e.g. binding affinity). 6. Antibody Modifications It may be desirable to tailor the antibody for various applications. Exemplary antibody modifications are described here. In certain embodiments ofthe invention, it may be desirable to use an antibody fragment, rather than an intact antibody. In this case, it may be desirable to modify the antibody fragment in order to increase its serum half-life. This may be achieved, for example, by incoφoration ofa salvage receptor binding epitope into the antibody fragment. See W096/32478 published October 17, 1996. Alternatively, the antibody may be conjugated to a nonproteinaceous polymer, such as those described above for the production of long half-life derivatives of OB protein. Where the antibody is to be used to treat cancer for example, various modifications ofthe antibody (e.g. ofa neutralizing antibody) which enhance the effectiveness ofthe antibody for treating cancer are contemplated herein. For example, it may be desirable to modify the antibody of the invention with respect to effector function. For example cysteine residue(s) may be introduced in the Fc region, thereby allowing interchain disulfide bond formation in this region. The homodimeric antibody thus generated may have improved internalization capability and/or increased complement-mediated cell killing and antibody-dependent cellular cytotoxicity (ADCC). See Caron et al, J. Exp Med. 176: 1 191-1 195 (1992) and Shopes, B. J. Immunol 148:2918-2922 ( 1992). Homodimeric antibodies with enhanced anti-tumor activity may also be prepared using heterobifunctional cross-linkers as described in Wolff et al Cancer Research 53:2560-2565 (1993). Alternatively, an antibody can be engineered which has dual Fc regions and may thereby have enhanced complement lysis and ADCC capabilities. See Stevenson et al. Anti-Cancer Drug Design 3:219-230 (1989). The invention also pertains to immunoconjugates comprising the antibody described herein conjugated to a cytotoxic agent such as a chemotherapeutic agent, toxin (e.g. an enzymaticaUy active toxin of bacterial, fungal, plant or animal origin, or fragments thereof), or a radioactive isotope (i.e., a radioconjugate). Chemotherapeutic agents useful in the generation of such immunoconjugates have been described above. EnzymaticaUy active toxins and fragments thereof which can be used include diphtheria A chain, nonbinding active fragments of diphtheria toxin, exotoxin A chain (from Pseudomonas aeruginosa), ricin A chain, abrin A chain, modeccin A chain, alpha-sarcin, Aleurites fordii proteins, dianthin proteins, Phytolaca americana proteins (PAPI, PAPII, and PAP-S), momordica charantia inhibitor, curcin, crotin, sapaonaria officinalis inhibitor, gelonin, mitogellin, restrictocin, phenomycin, enomycin and the tricothecenes. A variety of radionuclides are available for the production of radioconjugate antibodies. Examples include Bi, I, 13 1 In, 90 Y and , 86 Re. Conjugates ofthe antibody and cytotoxic agent are made using a variety of bifunctional protein coupling agents such as N-succinimidyl-3-(2-pyridyldithiol) propionate (SPDP), iminothiolane (IT), bifunctional derivatives of imidoesters (such as dimethyl adipimidate HCL), active esters (such as disuccinimidyl suberate), aldehydes (such as glutareldehyde), bis-azido compounds (such as bis (p-azidobenzoyl) hexanediamine), bis- diazonium derivatives (such as bis-(p-diazoniumbenzoyl)-ethylenediamine), diisocyanates (such as tolyene 2,6- diisocyanate), and bis-active fluorine compounds (such as 1 ,5-difluoro-2,4-dinitrobenzene). For example, a ricin immunotoxin can be prepared as described in Vitetta et al. Science 238: 1098 (1987). Carbon- 14-labeled 1 - isothiocyanatobenzyl-3-methyldiethylene triaminepentaacetic acid (MX-DTPA) is an exemplary chelating agent for conjugation of radionucleotide to the antibody. See W094/1 1026. In another embodiment, the antibody may be conjugated to a "receptor" (such streptavidin) for utilization in tumor pretargeting wherein the antibody-receptor conjugate is administered to the patient, followed by removal of unbound conjugate from the circulation using a clearing agent and then administration of a "ligand" (e.g. avidin) which is conjugated to a cytotoxic agent (e.g. a radionucleotide). The antibody may also be formulated as an immunoliposome. Liposomes containing the antibody are prepared by methods known in the art, such as described in Epstein et al, Proc. Natl Acad. Sci. USA, 82:3688 (1985); Hwang et al, Proc. Natl Acad. Sci. USA, 77:4030 (1980); and U.S. Pat. Nos. 4,485,045 and 4,544,545. Liposomes with enhanced circulation time are disclosed in U.S. Patent No. 5,013,556. Particularly useful liposomes can be generated by the reverse phase evaporation method with a lipid composition comprising phosphatidylcholine, cholesterol and PEG-derivatized phosphatidylethanolamine (PEG- PE). Liposomes are extruded through filters of defined pore size to yield liposomes with the desired diameter. Fab' fragments ofthe antibody ofthe present invention can be conjugated to the liposomes as described in Martin et al. J. Biol. Chem. 257: 286-288 (1982) via a disulfide interchange reaction. A chemotherapeutic agent (such as Doxorubicin) is optionally contained within the liposome. See Gabizon et al. J. National Cancer Inst.81(19) 1484 (1989). The antibody ofthe present invention may also be used in ADEPT by conjugating the antibody to a prodrug-activating enzyme which converts a prodrug (eg. a peptidyl chemotherapeutic agent, see W081/01 145) to an active anti-cancer drug. See, for example, WO 88/07378 and U.S. Patent No. 4,975,278. The enzyme component ofthe immunoconjugate useful for ADEPT includes any enzyme capable of acting on a prodrug in such a way so as to covert it into its more active, cytotoxic form. Enzymes that are useful in the method of mis invention include, but are not limited to, alkaline phosphatase useful for converting phosphate-containing prodrugs into free drugs; arylsulfatase useful for converting sulfate-containing prodrugs into free drugs; cytosine deaminase useful for converting non-toxic 5- fluorocytosine into the anti-cancer drug, 5-fluorouracil; proteases, such as serratia protease, thermolysin, subtilisin, carboxypeptidases and cathepsins (such as cathepsins B and L), that are useful for converting peptide- containing prodrugs into free drugs; D-alanylcarboxypeptidases, useful for converting prodrugs that contain D- amino acid substituents; carbohydrate-cleaving enzymes such as β-galactosidase and neuraminidase useful for converting glycosylated prodrugs into free drugs; β-lactamase useful for converting drugs derivatized with β- lactams into free drugs; and penicillin amidases, such as penicillin V amidase or penicillin G amidase, useful for converting drugs derivatized at their amine nitrogens with phenoxyacetyl or phenylacetyl groups, respectively, into free drugs. Alternatively, antibodies with enzymatic activity, also known in the art as "abzymes", can be used to convert the prodrugs of the invention into free active drugs (see, e.g., Massey, Nature 328: 457-458 (1987)). Antibody-abzyme conjugates can be prepared as described herein for delivery ofthe abzy e to a tumor cell population. The enzymes of this invention can be covalently bound to the antibody mutant by techniques well known in the art such as the use ofthe heterobifunctional crosslinking reagents discussed above Alternatively, fusion proteins comprising at least the antigen binding region of an antibody ofthe invention linked to at least a functionally active portion of an enzyme of the invention can be constructed using recombinant DNA techniques well known in the art (see, e.g. , Neuberger et al. Nature, 312: 604-608 (1984)). In other embodiments, the antibody can be covalently modified, with exemplary such modifications described above. E. Therapeutic Uses for WSX Receptor Ligands and Antibodies The WSX ligands (e.g. OB protein and anti-WSX receptor agonist antibodies) ofthe present invention are useful, in one embodiment, for weight reduction, and specifically, in the treatment of obesity, bulimia and other disorders associated with the abnormal expression or function ofthe OB and or WSX receptor genes, other metabolic disorders such as diabetes, for reducing excessive levels of insulin in human patients (e.g to restore or improve the insulin-sensitivity of such patients). Thus, these molecules can be used to treat a patient suffering from excessive food consumption and related pathological conditions such as type II adult onset diabetes, infertility (Chehab et al. Nature Genentics 12:318-320 ( 1996)), hypercholesterolemia, hyperlipidemia, cardiovascular diseases, arteriosclerosis, polycystic ovarian disease, osteoarthritis, dermatological disorders, insulin resistance, hypertriglyceridemia, cancer, cholelithiasis and hypertension. In addition, the WSX ligands can be used for the treatment of kidney ailments, hypertension, and lung dysfunctions, such as emphysema. In a further embodiment, the WSX ligands (such as agonist WSX receptor antibodies) ofthe present invention can be used to enhance repopulation of mature blood cell lineages in mammals having undergone chemo- or radiation therapy or bone marrow transplantation therapy. Generally, the ligands will act via an enhancement ofthe proliferation and/or differentiation (but especially proliferation) of primitive hematopoietic cells. The ligands may similarly be useful for treating diseases characterized by a decrease in blood cells. Examples of these diseases include: anemia (including macrocytic and aplastic anemia); thrombocytopenia; hypoplasia; immune (autoimmune) thrombocytopenic puφura (ITP); and HIV induced ITP. Also, the ligands may be used to treat a patient having suffered a hemorrhage. WSX ligands may also be used to treat metabolic disorders such as obesity and diabetes mellitus, or to promote kidney, Iiver or lung growth and/or repair (e.g., in renal failure). The WSX receptor ligands and antibodies may be administered alone or in concert with one or more cytokines. Furthermore, as an alternative to adminstration ofthe WSX ligand protein, gene therapy techniques (discussed in the section above entitled "Therapeutic Uses for the WSX Receptor") are also contemplated herein. Potential therapeutic applications for WSX receptor neutralizing antibodies include the treatment of metabolic disorders (such as cachexia, anorexia and other wasting diseases characterized by loss of appetite, diminished food intake or body weight loss), stem cell tumors and other tumors at sites of WSX receptor expression, especially those tumors characterized by overexpression of WSX receptor. For therapeutic applications, the WSX receptor ligands and antibodies ofthe invention are administered to a mammal, preferably a human, in a physiologically acceptable dosage form, including those that may be administered to a human intravenously as a bolus or by continuous infusion over a period of time, by intramuscular, intraperitoneal, intra-cerobrospinal, subcutaneous, intra-articular, intrasynovial, intrathecal, oral, topical, or inhalation routes. The WSX receptor ligands and antibodies also are suitably administered by intratumoral, peritumoral, intralesional, or perilesional routes or to the lymph, to exert local as well as systemic therapeutic effects. Such dosage forms encompass physiologically acceptable carriers that are inherently non-toxic and non- therapeutic. Examples of such carriers include ion exchangers, alumina, aluminum stearate, lecithin, serum proteins, such as human serum albumin, buffer substances such as phosphates, glycine, sorbic acid, potassium sorbate, partial glyceride mixtures of saturated vegetable fatty acids, water, salts, or electrolytes such as protamine sulfate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinyl pyrrolidone, cellulose-based substances, and PEG. Carriers for topical or gel-based forms of WSX receptor antibodies include polysaccharides such as sodium carboxymethylcellulose or methylcellulose, polyvinylpyrrolidone, polyacrylates, polyoxyethylene- polyoxypropylene-block polymers, PEG, and wood wax alcohols. For all administrations, conventional depot forms are suitably used. Such forms include, for example, microcapsules, nano-capsules, liposomes, plasters, inhalation forms, nose sprays, sublingual tablets, and sustained-release preparations. The WSX receptor ligand or antibody will typically be formulated in such vehicles at a concentration of about 0.1 mg/ml to 100 mg ml. Suitable examples of sustained-release preparations include semipermeable matrices of solid hydrophobic polymers containing the WSX receptor ligand or antibody, which matrices are in the form of shaped articles, e.g. films, or microcapsules. Examples of sustained-release matrices include polyesters, hydrogels (for example, poly(2-hydroxyethyl-methacrylate) as described by Langer et al, supra and Langer, supra, or poly(vinylalcohol), polylactides (U.S. Pat. No. 3,773,919), copolymers of L-glutamic acid and γ ethyl-L- glutamate (Sidman et al, supra), non-degradable e ylene-vinyl acetate (Langer et al, supra), degradable lactic acid-glycolic acid copolymers such as the Lupron Depot (injectable microspheres composed of lactic acid- glycolic acid copolymer and leuprolide acetate), and poly-D-(-)-3-hydroxybutyric acid. While polymers such as ethylene-vinyl acetate and lactic acid-glycolic acid enable release of molecules for over 100 days, certain hydrogels release proteins for shorter time periods. When encapsulated WSX receptor antibodies remain in the body for a long time, they may denature or aggregate as a result of exposure to moisture at 37° C, resulting in a loss of biological activity and possible changes in immunogenicity. Rational strategies can be devised for stabilization depending on the mechanism involved. For example, if the aggregation mechanism is discovered to be intermolecular S-S bond formation through thio-disulfide interchange, stabilization may be achieved by modifying sulfhydryl residues, lyophilizing from acidic solutions, controlling moisture content, using appropriate additives, and developing specific polymer matrix compositions. Sustained-release WSX receptor ligand or antibody compositions also include liposomal ly entrapped antibodies. Liposomes containing the WSX receptor ligand or antibody are prepared by methods known in the art, such as described in Epstein et al , Proc Natl Acad Set USA 82 3688 (1985), Hwang et al , Proc Natl Acad Sci USA 11 4030 (1980), and U S Pat Nos 4,485,045 and 4,544,545 Ordinarily, the liposomes are the small (about 200-800 Angstroms) unilamelar type in which the lipid content is greater than about 30 mol % cholesterol, the selected proportion being adjusted for the optimal WSX receptor ligand or antibody therapy Liposomes with enhanced circulation time are disclosed in U S Patent No 5,013,556 For the prevention or treatment of disease, the appropriate dosage of WSX receptor ligand or antibody will depend on the type of disease to be treated, as defined above, the severity and course ofthe disease, whether the antibodies are administered for preventive or therapeutic puφoses, previous therapy, the patient's clinical history and response to the WSX receptor ligand or antibody, and the discretion ofthe attending physician The WSX receptor ligand or antibody is suitably administered to the patient at one time or over a series of treatments Depending on the type and severity ofthe disease, about 1 μg/kg to 15 mg/kg of WSX receptor ligand or antibody is an initial candidate dosage for administration to the patient, whether, for example, by one or more separate administrations, or by continuous infusion A typical daily dosage might range from about 1 μg/kg to 100 μg/kg ( g 1-50 μg/kg) or more, depending on the factors mentioned above For example, the dose may be the same as that for other cytokmes such as G-CSF, GM-CSF and EPO For repeated administrations over several days or longer, depending on the condition, the treatment is sustained until a desired suppression of disease symptoms occurs However, other dosage regimens may be useful The progress of this therapy is easily monitored by conventional techniques and assays When one or more cytokines are co-adm mistered with the WSX receptor ligand, lesser doses of the WSX ligand may be employed Suitable doses of a cytokine are from about 1 μg/kg to about 15mg/kg of cytokine A typical daily dosage ofthe cytokine might range from about 1 μg/kg to 100 μg/kg (e g 1 -50 μg/kg) or more For example, the dose may be the same as that for other cytokines such as G-CSF, GM-CSF and EPO The cytokιne(s) may be administered prior to, simultaneously with, or following administration of the WSX ligand The cytokιne(s) and WSX ligand may be combined to form a pharmaceutically composition for simultaneous administration to the mammal In certain embodiments, the amounts of WSX ligand and cytokine are such that a synergistic repopulation of blood cells (or synergistic increase in proliferation and/or differentiation of hematopoietic cells) occurs in the mammal upon administration of the WSX ligand and cytokine thereto In other words, the coordinated action ofthe two or more agents (/ e the WSX ligand and cytokιne(s)) with respect to repopulation of blood cells (or proliferation/differentiation of hematopoietic cells) is greater than the sum ofthe individual effects of these molecules For treating obesity and associated pathological conditions, the WSX ligand may be administered in combination with other treatments for combatting or preventing obesity Substances useful for this puφose include, e g , hormones (catecholamtnes, glucagon, ACTH), clofibrate, halogenate, cmchocame, chloφromazine, appetite-suppressing drugs acting on noradrenergic neurotransmitters such as mazmdol and derivatives of phenethylamme, e g , phenylpropanolamine, diethylpropion, phentermme, phendimetrazine, benzphetamine, amphetamine, methamphetamine, and phenmetrazine, drugs acting on serotonin neurotransmitters such as fenfluramine, tryptophan, 5-hydroxytryptophan, fluoxetine, and sertraline, centrally active drugs such as naloxone, neuropeptide-Y, galanin, corticotropin-releasing hormone, and cholecystokimπ, a chohnergic agonist such as pyπdostigmme, a sphingolipid such as a lysosphingolipid or derivative thereof (EP 321 ,287 published June 21 , 1989); thermogenic drugs such as thyroid hormone, ephedrine, beta-adrenergic agonists; drugs affecting the gastrointestinal tract such as enzyme inhibitors, e.g., tetrahydrolipostatin, indigestible food such as sucrose polyester, and inhibitors of gastric emptying such as threo-chlorocitric acid or its derivatives; β-adrenergic agonist such as isoproterenol and yohimbine; aminophylline to increase the β-adrenergic-like effects of yohimbine, an o^-adrenergic blocking drug such as clonidine alone or in combination with a growth hormone releasing peptide (U.S. Pat. No. 5,120,713 issued June 9, 1992); drugs that interfere with intestinal absoφtion such as biguanides such as metformin and phenformin; bulk fillers such as methylcellulose; metabolic blocking drugs such as hydroxycitrate; progesterone; cholecystokinin agonists; small molecules that mimic ketoacids; agonists to corticotropin-releasing hormone; an ergot-related prolactin-inhibiting compound for reducing body fat stores (U.S. Pat. No. 4,783,469 issued November 8, 1988); beta-3-agonists; bromocriptiπe; antagonists to opioid peptides; antagonists to neuropeptide Y; glucocorticoid receptor antagonists; growth hormone agonists; combinations thereof; etc. This includes all drugs described by Bray and Greenway, Clinics in Endocrinol and Metabol, 5:455 (1976). These adjunctive agents may be administered at the same time as, before, or after the administration of WSX ligand and can be administered by the same or a different administration route than the WSX ligand. The WSX ligand treatment may occur without, or may be imposed with, a dietary restriction such as a limit in daily food or calorie intake, as is desired for the individual patient. F. Articles of Manufacture In another embodiment ofthe invention, an article of manufacture containing materials useful for the treatment ofthe conditions described above is provided. The article of manufacture comprises a container and a label. Suitable containers include, for example, bottles, vials, syringes, and test tubes. The containers may be formed from a variety of materials such as glass or plastic. The container holds a composition which is effective for treating the condition and may have a sterile access port (for example the container may be an intravenous solution bag or a vial having a stopper pierceable by a hypodermic injection needle). The active agent in the composition is the WSX ligand. The label on, or associated with, the container indicates that the composition is used for treating me condition of choice. The article of manufacture may further comprise a second container holding a cytokine for co-administration with the WSX ligand. Further container(s) may be provided with the article of manufacture which may hold, for example, a pharmaceutically-acceptable buffer, such as phosphate- buffered saline, Ringer's solution or dextrose solution. The article of manufacture may further include other materials desirable from a commercial and user standpoint, including other buffers, diluents, filters, needles, syringes, and package inserts with instructions for use. G. Non-Therapeutic Uses for WSX Receptor Ligands and Antibodies WSX receptor ligands and antibodies may be used for detection of and/or enrichment of hematopoietic stem cell/progenitor cell populations in a similar manner to that in which CD34 antibodies are presently used. For stem cell enrichment, the WSX receptor antibodies may be utilized in the techniques known in the art such as immune panning, flow cytometry or immunomagnetic beads. In accordance with one in vitro application ofthe WSX ligands, cells comprising the WSX receptor are provided and placed in a cell culture medium. Examples of such WSX-receptor-containing cells include hematopoietic progenitor cells, such as CD34+ cells. Suitable tissue culture media are well known to persons skilled in the art and mclude, but are not limited to, Minimal Essential Medium (MEM), RPMI-1640, and Dulbecco's Modified Eagle's Medium (DMEM) These tissue culture medias are commercially available from Sigma Chemical Company (St Louis, MO) and GIBCO (Grand Island, NY) The cells are then cultured the cell culture medium under conditions sufficient for the cells to remain viable and grow in the presence of an effective amount of WSX ligand and, optionally, further cytokines and growth factors The cells can be cultured in a variety of ways, including culturing in a clot, agar, or liquid culture The cells are cultured at a physiologically acceptable temperature such as 37° C, for example, in the presence of an effective amount of WSX ligand The amount of WSX ligand may vary, but preferably is in the range of about 10 ng/ml to about lmg/ml The WSX ligand can of course be added to the culture at a dose determined empirically by those in the art without undue experimentation The concentration of WSX ligand in the culture will depend on various factors, such as the conditions under which the cells and WSX ligand are cultured The specific temperature and duration of incubation, as well as other culture conditions, can be varied depending on such factors as, e , the concentration ofthe WSX ligand, and the type of cells and medium It is contemplated that using WSX ligand to enhance cell proliferation and/or differentiation in vitro will be useful in a variety of ways For instance, hematopoietic cells cultured in vitro in the presence of WSX ligand can be infused into a mammal suffering from reduced levels ofthe cells Also, the cultured hematopoietic cells may be used for gene transfer for gene therapy applications Stable in vitro cultures can be also used for isolating cell-specific factors and for expression of endogenous or recombinantly introduced proteins in the cell WSX ligand may also be used to enhance cell survival, proliferation and/or differentiation of cells which support the growth and/or differentiation of other cells in cell culture The WSX receptor antibodies ofthe invention are also useful as affinity purification agents In this process, the antibodies against WSX receptor are immobilized on a suitable support, such a Sephadex resm or filter paper, using methods well known in the art The immobilized antibody then is contacted with a sample contammg the WSX receptor to be purified, and thereafter the support is washed with a suitable solvent that will remove substantially all the material in the sample except the WSX receptor, which is bound to the immobilized antibody Finally, the support is washed with another suitable solvent, such as glycine buffer, pH 5 0, that will release the WSX receptor from the antibody WSX receptor antibodies may also be useful in diagnostic assays for WSX receptor, e g , detecting its expression in specific cells, tissues, or serum For diagnostic applications, antibodies typically will be labeled with a detectable moiety The detectable moiety can be any one which is capable of producing either directly or indirectly, a detectable signal For example, the detectable moiety may be a radioisotope, such as H, C, P, S, or I, a fluorescent or chemiluminescent compound, such as fluorescein isothiocyanate, rhodamine, 17S 31 14 3 or lucifenn, radioactive isotopic labels, such as, e g , I, P, C, or J H, or an enzyme, such as alkaline phosphatase, beta-galactosidase, or horseradish peroxidase Any method known in the art for separately conjugating the polypeptide variant to the detectable moiety may be employed, including those methods described by Hunter et al , Nature 144 945 (1962), David et al , Biochemistry 13 1014 (1974); Pain et al , J Immunol Meth 40 219 (1981), and Nygren, J Htstochem and Cytochem 30 407 (1982) The antibodies of the present invention may be employed in any known assay method, such as competitive binding assays, direct and indirect sandwich assays, and immunoprecipitation assays Zola, Monoclonal Antibodies A Manual of Techniques, pp 147-158 (CRC Press, Inc , 1987) Competitive binding assays rely on the ability ofa labeled standard to compete with the test sample analyte for binding with a limited amount of antibody The amount of WSX receptor in the test sample is inversely proportional to the amount of standard mat becomes bound to the antibodies To facilitate determmmg the amount of standard that becomes bound, the antibodies generally are insolubilized before or after the competition, so that the standard and analyte that are bound to me antibodies may conveniently be separated from the standard and analyte which remain unbound Sandwich assays involve the use of two antibodies, each capable of binding to a different immunogenic portion, or epitope, ofthe protein to be detected In a sandwich assay, the test sample analyte is bound by a first antibody which is immobilized on a solid support, and thereafter a second antibody binds to the analyte, thus forming an insoluble three-part complex See, e g , US Pat No 4,376, 1 10 The second antibody may itself be labeled with a detectable moiety (direct sandwich assays) or may be measured using an anti-immunoglobulm antibody that is labeled with a detectable moiety (mdirect sandwich assay) For example, one type of sandwich assay is an ELISA assay, in which case the detectable moiety is an enzyme H. Deposit of Materials The following biological materials have been deposited with the American Type Culture Collection, 12301 Parklawn Drive, Rockville, MD, USA (ATCC) Deposit Designation ATCC No. Deposit Date Baf3/WSX E63x7 sort ATCC CRL 12015 Jan 10, 1996 (Baf3 cells expressing human WSX receptor variant 13 2) 2D7 hybridoma cell line 1G4 hybridoma cell line ATCC HB-12243 Dec 1 1 , 1996 1E1 1 hybridoma eel I l e 1C1 1 hybridoma cell lme These deposits were made under the provisions ofthe Budapest Treaty on the International Recognition ofthe Deposit of Microorganisms for the Purpose of Patent Procedure and the Regulations thereunder (Budapest Treaty) This assures mamtenance of a viable culture for 30 years from the date of deposit Each of the deposited cultures will be made available by ATCC under the terms ofthe Budapest Treaty, and sub j ect to an agreement between Genentech, Inc and ATCC, which assures (a) that access to the culture will be available durmg pendency ofthe patent application to one determined by the Commissioner to be entitled thereto under 37 CFR § 1.14 and 35 USC §122, and (b) that all restrictions on the availability to the public ofthe culture so deposited will be irrevocably removed upon the granting ofthe patent. The assignee ofthe present application has agreed that if any ofthe cultures on deposit should die or be lost or destroyed when cultivated under suitable conditions, it will be promptly replaced on notification with a viable specimen ofthe same culture. Availability ofthe deposited cell lines is not to be construed as a license to practice the invention in contravention of the rights granted under the authority of any government in accordance with its patent laws. The foregoing written specification is considered to be sufficient to enable one skilled in the art to practice the invention. The present invention is not to be limited in scope by any culture deposited, since the deposited embodiment is intended as an illustration of one aspect of the invention and any culture that is functionally equivalent is within the scope of this invention. The deposit of material herein does not constitute an admission that the written description herein contained is inadequate to enable the practice of any aspect of me invention, including the best mode thereof, nor is it to be construed as limiting the scope ofthe claims to the specific illustration that it represents. Indeed, various modifications ofthe invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description and fall within the scope of the appended claims. III. Experimental Below are examples of specific embodiments for carrying out the present invention. The examples are offered for illustrative puφoses only, and are not intended to limit the scope ofthe present invention in any way. The disclosures of all publications, patents and patent applications cited herein, whether supra or infra, are hereby incoφorated by reference in their entirety. EXAMPLE 1 Cloning of Human WSX Receptor An oligonucleotide probe designated WSX.6 # 1 was synthesized based upon the T73849 EST sequence. The WSX.6 #1 probe was a 51mer having the following sequence: 5' GTCAGTCTCCCAGTTCCAGACTTGTGTGCAGTCTATGCTGTTCAGGTGCGC - 3' (SEQ ID NO:45). The radiolabeled WSX.6 #1 probe was used to probe 1.2 x 10 clones from a random and oligo dT primed λgt 10 fetal liver library (Clontech, Palo Alto, CA). Following hybridization at 42° C overnight, the filters were washed at 50° C in 0.5 x SSC and 0.1% NaDodSO^ (SDS). From the initial screen, 10 clones were selected and upon subsequent screening 5 individual plaque pure clones were isolated. Of these 5 individual clones, four clones designated 1, 5, 6 and 9 were subcloned into pBSSK " (Stratagene) following EcoRI digestion. Sequence analysis revealed clone 5 and clone 9 contained the putative initiation methionine and signal peptide. Clone 6 (designated 6.4) contained the most 3' end sequence and subsequently was used for further screening. To obtain the full length gene, clone 6.4 (fragment Nsi-Hind HI) was radiolabeled and used to screen 1.2 x 10 clones from a λgt 10 library constructed from a hepatoma Hep3B cell line. This screen resulted in 24 positive clones. Following PCR analysis ofthe clones using λgtlO primers (F and R), the four longest clones 12.1, 13.2, 22.3, and 24.3 were isolated. These clones were subcloned into pBSSK " using the EcoRI site, and following examination by restriction enzyme digest, clones 12.1 and 13.2 were submitted for sequencing. D A sequencing was performed with the Taq dye deoxynucleotide terminator cycle sequencing kit on an automated Applied Biosystems DNA sequencer. The assembled contiguous sequence from all the isolated clones encoded a consensus amino terminus for the newly identified polypeptide designated the WSX receptor. However, sequence analysis revealed that at least three naturally occurring variants ofthe WSX receptor exist which have different cytoplasmic regions. These variants appear to be differentially spliced at the lysine residue at position 891. Clone 6.4 stops 5 amino acids after Lys 891. Clone 12.1 is different from 13.2 and 6.4 following Lys 891 and encodes a putative box 2 region which is distinct from that encoded by clone 13.2. Clone 13.2 contains a potential box 1 region and following Lys 891 encodes putative box 2 and box 3 motifs. See, Baumann e/α/., Mol. Cell. Biol. 14(1): 138- 146 (1994). The full length WSX gene based on the clone 13.2 cytoplasmic region putatively encodes an 1 165 amino acid transmembrane protein. The 841 amino acid extracellular domain (ECD) contains two WSXWS domains. The ECD is followed by a 24 amino acid transmembrane domain and a 300 amino acid cytoplasmic region. EXAMPLE 2 WSX Receptor Immunoadhesin Using polymerase chain amplification, a WSX receptor immunoadhesin was created by engineering an in-frame fusion ofthe WSX receptor gene extracellular domain (WSX.ECD) with human CH2CH3(Fc)lgG (Bennett et al, J.Biol Chem. 266(34):23060-23067 (1991)) at the C terminus of the ECD and cloned into pBSSK * (Stratagene). For expression, the WSX-Fc was excised with Clal and BstEII and ligated into the pRK5.HuIF.grbhIgG Genenase I vector (Beck et al, Molecular Immunology 31 (17): 1335-1344 (1994)), to create the plasmid pRK5. WSX-IgG Genenase I. This plasmid was transiently transfected into 293 cells using standard calcium phosphate transfection techniques. The transfected cells were cultured at 37° C in 5% CO2 in DMEM F12 50:50 supplemented with 10% FBS, lOOmM HEPES (pH 7.2) and ImM giutamine. The WSX receptor immunoadhesin was purified using a ProSepA™ protein A column. EXAMPLE 3 Antibody Production In order to raise antibodies against the WSX receptor, the WSX receptor immunoadhesin of Example 2 was used to inoculate rabbits to raise polyclonal antibodies and mice to raise monoclonal antibodies using conventional technology. EXAMPLE 4 Generation ofa Cell Line Expressing WSX Receptor The nucleic acid encoding full length WSX receptor variant 13.2 was inserted in the pRKtkNeo plasmid (Holmes et al, Science 253: 1278- 1280 (1991)). 100 μgs of the pRKtkNeo.WSX plasmid thus generated was linearized, ethanol precipitated and resuspended in 100 μL of RPMI 1640. 7 x IO 6 BaO cells (5 x 10 5 /ml) were suspended in 900 μL of RPMI and added to the linearized plasmid. Following electroporation at 325V, 1 180 μF using a BRL electroporation apparatus, the cells were plated into 15 mis of RPMI 1640 containing 5% WEHI3B conditioned media and 15% serum. 48 hours later cells were selected in 2mg/ml G418. To obtain the Baf3/WSX cell line expressing WSX receptor variant 13.2, the G418 selected clones were analyzed by FACS using the rabbit polyclonal antisera raised against the WSX-Fc chimeric protein as described above. The highest expressing clone (designated E6) was sorted by FACS to maintain a population with a high level of WSX receptor expression. EXAMPLE 5 Role of WSX Receptor in Cellular Proliferation The proliferative potentials of WSX receptor variants 13 2 and 12 1 were tested by constructing human growth hormone receptor- WSX receptor (GH-WSX) fusions encoding chimeric proteins consisting ofthe GH receptor extracellular and transmembrane domains and the WSX receptor variant 13 2 or 12 1 intracellular domains These chimeπc gene fusions were transfected into the IL-3 dependent cell line BaO The ability of the GH-WSX transfected BaO cells to respond to exogenous growth hormone (GH) was tested in a thymidine incoφoration assay As can be seen in Figs 6 and 8, the GH-WSX receptor variant 13 2 chimera was capable of increasing thymidine uptake in the transfected BaO cells, thus indicating the proliferative potential of the WSX receptor variant 13 2 However, WSX receptor variant 12 1 was unable to transmit a proliferative signal in this experiment (Fig. 8) Materials and Methods Recombinant PCR was used to generate the chimeric receptors containing the extracellular and transmembrane domams ofthe hGH receptor and the cytoplasmic domain of either WSX receptor variant 12 1 or variant 13 2 In short, the cytoplasmic domain of either variant 12 1 or 13 2 beginning with Arg at amino acid 866 and extendmg down to ammo acid 958 or ammo acid 1 165 respectively, was fused in frame, by sequential PCR, to the hGH receptor extracellular and transmembrane domain beginning with Met at ammo acid 18 and extending down to Arg at ammo acid 274 The GH-WSX chimera was constructed by firsl using PCR to generate the extracellular and transmembrane domain ofthe human GH receptor The 3' end primer used for this PCR contamed 20 nucleotides at the 5' end ofthe primer corresponding to the first 20 nucleotides of the WSX cytoplasmic domain The 3' end ofthe chimera was generated usmg PCR where the 5' end pπmer contained the last 19 nucleotides of me human GH receptor transmembrane domain To generate the full length chimera, the 5' end ofthe human GH receptor product was combmed with the 3' end WSX receptor cytoplasmic PCR product and subsequently amplified to create a fusion ofthe two products This chimeric fusion was digested with Clal and Xbal and ligated to pRKtkNeo (Holmes et al , Science 253 1278-1280 (1991)) to create the chimeric expression vector The IL-3 dependent cell line BaO was then electroporated with this hGH/WSX chimeric expression vector Briefly, lOOμg of the pRKtkNeo/GH WSX plasmid was linearized, ethanol precipitated and resuspended in 100 μL of RPMI 1640 7 x IO 6 BaO cells (5 x 10 5 /ml) were suspended in 900 μL of RPMI and added to the linearized plasmid Following electroporation at 325V, 1 180 μF using a BRL electroporation apparatus, the cells were plated into 15 mis of RPMI 1640 containing 5% wehi conditioned media and 15% serum 48 hours later, cells were selected in 2mg/ml G418 To obtain the BaO/GH WSX cell lines, the G418 selected cells were FACS sorted usmg an anti-human GH mAb (3B7) at 1 μg/ml The top 10% expressmg cells were selected and expanded EXAMPLE 6 Expression Analysis of the WSX Receptor The expression profile of the WSX receptor was initially examined by Northern analysis Northern blots of human fetal or adult tissue mRNA were obtained from Clontech (Palo Alto, California) A transcript of approximately 6 kb was detected in human fetal lung, liver and kidney In the adult, low level expression was detected in a variety of tissues including liver, placenta, lung skeletal muscle, kidney, ovary, prostate and small intestine. PCR analysis of human cord blood identified transcripts in CD34 + subfraction. By PCR analysis, all three variants ofthe WSX receptor were present in CD34 + cells. The CD34 " subfraction appeared negative by this same PCR analysis. By PCR analysis, both the 6.4 variant and 13.2 variant were evident in the AA4 + Sca + Kit + (flASK) cell population isolated from the mid-gestation fetal liver as described in Zeigler et al, Blood 84:2422-2430 (1994). No clones containing the 12.1 variant cytoplasmic tail have been isolated from murine tissues. Human B cells isolated from peripheral blood using anti-CD 19/20 antibodies were also positive for short form (6.4 variant) and long from (13.2 variant) receptor mRNA expression. The WSX receptor appears to be expressed on both progenitor and more mature hematopoietic cells. EXAMPLE 7 Cloning of Murine WSX Receptor The human WSX receptor was used as a probe to isolate murine WSX receptor. The pRKtkNeo. WSX plasmid of Example 4 was digested using Sspl . This Sspl fragment (1624 bps) was isolated, and radiolabelled, and used to screen a murine liver λgtlO library (Clontech). This resulted in 4 positive clones which were isolated and sequenced after sub-cloning into pBSSK " via EcoRI digestion. The resultant clones, designated 1, 2, 3, 4 showed homology to the extracellular domain ofthe human WSX receptor; the contiguous sequences resulting from these clones extended from the initiation methionine to tryptophan at position 783. The overall similarity of human WSX receptor and murine WSX receptor is 73 % over this region of the respective extracellular domains (see Figs. 4A-B). EXAMPLE 8 The Role of WSX Receptor in Hematopoietic Cell Proliferation The presence ofthe WSX receptor in the enriched human stem cell population CD34 + from cord blood is indicative of a potential role for this receptor in stem cell/progenitor cell proliferation. The proliferation of CD34 human blood cells in methylcellulose media (Stem Cell Technologies) was determined in the presence or absence of WSX receptor antisense oligonucleotides. These experiments were also repeated in the murine hematopoietic system using AA4 + Sea Kit stem cells from the murine fetal liver. In both instances, the antisense oligonucleotides statistically significantly inhibited colony formation from the hematopoietic progenitor cells. See Table 1 below. The anti-proliferative effects were most pronounced using the -20 antisense and the +85 antisense oligonucleotide constructs. This inhibition was not lineage specific to any particular myeloid lineage that resulted from the progenitor expansion. The principal effect ofthe antisense oligonucleotides was a reduction of overall colony numbers. The size ofthe individual colonies was also reduced. Antisense oligonucleotide experiments using both human and murine stem cells demonstrated an inhibition of myeloid colony formation. Although, the reduction in myelopoiesis observed in these assays could be prevented by the additional inclusion of G-CSF and GM-CSF in the culture medium. These data serve to illustrate the redundancy of cytokine action in the myelopoietic compartment. TABLE 1 EXPERIMENT OLIGO AVG. COLONY # % INHIBITION Human Cord Blood (KL) (-20)AS 32 (-20)S 100 70 (-20)SCR 1 14 (+85)AS 80 (+85)S 123 38 (+85)SCR 138 Control 158 Human Cord Blood (-20)AS 78 (IL-3, IL-6, KL) (-20)S 188 54 (-20)SCR 151 (+85)AS 167 (+85)S 195 18 (+85)SCR 213 Control 266 Human Cord Blood (KL) (-20)AS 42 (-20)S 146 69 (-20)SCR 121 (+85)AS 123 (+85)S 162 23 (+85)SCR 156 Control 145 Murine Fetal Liver (KL) (+84)AS 33 (+84)S 86 54 (+84)SCR 57 (-20)AS 27 (-20)S 126 71 (-20)SCR 60 (-99)AS 109 (-99)S 93 0 (-99)SCR 109 Control 121 Murine Fetal Liver (KL) (-213)AS 51 (-213)S 60 10 (-213)SCR 53 (+211)AS 58 (+2I 1)S 54 3 (+21 1)SCR 66 Control 59 Materials and Methods Human stem cells: Human umbilical cord blood was collected in PBS/Heparin (lOOOμ/ml). The mononuclear fraction was separated using a dextran gradient and any remaining red blood cells lysed in 20 mM NH4 Cl. CD34 + cells were isolated using CD34 + immunomagnetic beads (Miltenyi, CA). These isolated CD34 + cells were found to be 90-97% CD34 + by FACS analysis. Murine stem cells Midgestation fetal liver were harvested and positively selected for the AA4 " antigen by immune panning The AA4 " positive fraction was then further enriched for stem cell content by FACS isolation ofthe AA4 + Sca + Kιt + fraction Antisense experiments Oligodeoxynucleotides were synthesized against regions of the human or murine WSX receptors For each oligonucleotide chosen, antisense (AS), sense (S) and scrambled (SCR) versions were synthesized (see Fig 7) + or - indicates position relative the initiation methionine ofthe WSX receptor CD34 + or AA4 + Sca + Kιt + cells were incubated at a concentration of 10 3 /ml in 50 50 DMEM/F12 media supplemented with 10% FBS, L-glutamine, and GIBCO™ lipid concentrate containing either sense, antisense or scrambled oligonucleotides at a concentration of 70 μg/ml After 16 hours, a second aliquot of the respective oligonucleotide was added (35 μg/ml) and the cells incubated for a further 6 hours Colony assays 5000 cells from each of the above conditions were a quoted into 5 ml of methylcellulose (Stem Cell Technologies) contammg kit ligand (KL) (25 ng/ml), mterleukιn-3 (IL-3) (25 ng/ml) and ιnterleukm-6 (IL-6) (50 ng/ml) The methylcellulose cultures were then incubated at 37° C for 14 days and the resultant colonies counted and phenotyped All assays were performed in triplicate EXAMPLE 9 WSX Receptor Variant 13.2 is a Receptor for OB Protein The WSX receptor variant 13 2 has essentially the same ammo acid sequence as the recently cloned leptin (OB) receptor See Tartaglia et al , Cell 83 1263- 1271 ( 1995) OB protein was able to stimulate thymidine incoφoration in BaO cells transfected with WSX receptor variant 13 2 as described in Example 4 (See Fig 9) OB protein expression in hematopoietic cells was studied Oligonucleotide primers designed specifically against the OB protem illustrated the presence of this ligand in fetal liver and fetal brain as well as in two fetal liver stromal cell lines, designated 10-6 and 7-4 Both of these immortalized stromal cell lines have been demonstrated to support both myeloid and lymphoid proliferation of stem cell populations (Zeigler et al , Blood M 2422-2430 (1994)) EXAMPLE 10 Role of OB Protein in Hematopoiesis To examine the hematopoietic activity of OB protein, a variety of in vitro assays were performed Murine fetal liver flASK stem cells were isolated from the midgestational fetal liver as described in Zeigler et al , Blood 84.2422-2430 (1994) and studied stem cell suspension culture or methylcellulose assays For the stem cell suspension cultures, twenty thousand ofthe fLASK cells were seeded in individual wells in a 12 well format in DMEM 4.5/F12 media supplemented with 10% heat inactivated fetal calf serum (Hyclone, Logan, UT) and L-glutamine Growth factors were added at the following concentrations kit ligand (KL) at 25 ng/mL, ιnterleukιn-3 (IL-3) at 25 ng/mL, ιnterleukιn-6 (IL-6) at 50 ng/mL, G-CSF at 100 ng/mL, GM- CSF at 100 ng/mL, EPO at 2U/mL, mterleukιn-7 (IL-7) at 100 ng/mL (all growth factors from R and D Systems, Minneapolis, MN). OB protein was added at 100 ng/mL unless indicated otherwise. Recombinant OB protein was produced as described in Levin et al, Proc. Natl. Acad. Sci. (USA) 93: 1726-1730 (1996). In keeping with its ability to transduce a proliferative signal in BaO cells (see previous Example), OB protein dramatically stimulated the expansion of flASK cells grown in suspension culture in the presence of kit ligand (Fig. 10A). The addition of OB protein alone to these suspension cultures was unable to effect survival ofthe hematopoietic stem cells (HSCs). When a variety of hematopoietic growth factors in suspension culture assays were tested, the main synergy of OB protein appeared to be with KL, GM-CSF and IL-3 (Table 2). No preferential expansion of any particular lineage was observed from cytospin analysis ofthe resultant cultures. TABLE 2 Factor KL KL+OB protein OB protein N/A 128+/-9 192+/- 13 G-CSF 131+/-3 177+/-8 30+/-5 GM-CSF 148+/-4 165+/-6 134+/- 10 IL-3 189+/-7 187+/-4 144+/- IL-6 1 12+/-4 198+/-5 32+Λ3 EPO 121 +/-3 177+/-8 30+/-6 IL-3 & IL-6 1 12+/-12 198+/-7 32+Λ7 flASK stem cells were isolated. Twenty thousand cells were plated in suspension culture with the relevant growth factor combination. Cells were harvested and counted after 7 days. Cell numbers are presented x 10 . Assays were performed in triplicate and repeated in two independent experiments. Methylcellulose assays were performed as previously described (Zeiger et al., supra). Briefly, methylcellulose colony assays were performed using "complete" methylcellulose or pre-B methylcellulose medium (Stem Cell Technologies, Vancouver, British Columbia, Canada) with the addition of 25 ng/mL KL (R and D Systems, Minneapolis, MN). Cytospin analyses ofthe resultant colonies were performed as previously described in Zeigler et al. When these methylcellulose assays were employed, OB protein augmented myeloid colony formation and dramatically increased lymphoid and erythroid colony formation (Figs. 10B and 10C) which demonstrates that OB protein can act on very early cells ofthe hematopoietic lineage. Importantly, the hematopoietic activity of OB protein was not confined to fetal liver stem cells, the murine bone marrow stem cell population; Lin Sca + also proliferated in response to OB protein (KL: 5 fold expansion, KL and OB protein: 10 fold expansion). Further hematopoietic analysis of the role of the WSX receptor was carried out by examining hematopoietic defects in the db/db mouse. These defects were assessed by measuring the proliferative potential of db/db homozygous mutant marrow. Under conditions favoring either myeloid (Humphries et al, Proc. Natl Acad. Sci. (USA) 78:3629- 3633 (1981 )) or lymphoid (McNiece et al, J. Immunol. 146:3785-90 (1991)) expansion, the colony forming potential ofthe db/db marrow was significantly reduced when compared to the wild-type control marrow (Fig. 1 1). This was particularly evident when the comparison was made under pre-B methylcellulose conditions where KL and IL-7 are used to drive lymphopoiesis (McNiece et al, supra). Corresponding analysis of the complementary mouse mutation ob/ob, which is deficient in the production of OB protein (Zhang et al, Nature 372:425-431 (1994)), also indicated that the lymphoproliferative capacity is compromised in the absence ofa functional OB protein signalling pathway (Fig. 1 1 ). However, this reduction was less than the reduction observed using db/db marrow. Analysis of the cellular profile of the db/db and wild-type marrow revealed significant differences between the two. Overall cellularity of the db/db marrow was unchanged. However, when various B cell populations in the db/db marrow were examined, both decreased levels of B220 + and B220 + /CD43 + cells were found. B220 + cells represent all B cell lineages while CD43 is considered to be expressed preferentially on the earliest cells of the B cell hierarchy (Hardy et al, J. Exp. Med. 173: 1213-25 ( 1991)). No differences were observed between the CD4/CD8 staining profiles ofthe two groups. The TER1 19 (a red cell lineage marker) population was increased in the db/db marrow (Fig. 12A). Comparison ofthe spleens from the two groups revealed a significant decrease in both tissue weight and cellularity of the db/db mice compared to the homozygote misty gray controls (0.063 ±0.009 g vs. 0.037±0.006 g and 1.10xl0 7 ±lxl0 4 vs.4.3xl0 6 ±10 3 cells > pθ.05). This decreased cellularity in the db spleen was reflected in a marked reduction in TER119 staining (Fig. 12B). This result appears to confirm the synergy demonstrated between OB protein and EPO and points to a role for OB protein in the regulation of erythropoiesis. Examination ofthe hematopoietic compartment ofthe db/db mouse in vivo demonstrated a significant reduction in peripheral blood lymphocytes when compared to heterozygote or wild-type controls. Db/db mice fail to regulate blood glucose levels and become diabetic at approximately 6-8 weeks of age; therefore, peripheral blood counts as the animals matured were followed. For procurement of blood samples, prior to the experiment and at time points throughout the study, 40 μL of blood was taken from the orbital sinus and immediately diluted into 10 mL of diluent to prevent clotting. The complete blood count from each blood sample was measured on a Serrono Baker system 9018 blood analyzer within 60 min. of collection. Only half the animals in each dose group were bled on any given day, thus, each animal was bled on alternate time points. Blood glucose levels were measured in orbital sinus blood samples using One Touch glucose meters and test strips (Johnson and Johnson). The results of this experiment are shown in Figs. 13A-C. This analysis demonstrated that peripheral blood lymphocytes are significantly reduced at all time points compared to control animals and that the peripheral lymphocyte population ofthe db/db mouse does not change significantly with age. FACS analysis revealed that the decreased lymphocyte population represented a decrease in both B220 + cells and CD4/CD8 cells. Both erythrocyte and platelets are at wild-type levels throughout all time periods examined. The peripheral blood lymphocyte levels in ob/ob homozygous mutant mice were unchanged from wild-type controls. Hematopoietic analysis ofthe db/db mouse can be complicated by the onset of diabetes. Therefore, the impact of high glucose levels on lymphopoiesis was examined by comparing the peripheral blood profiles and blood glucose levels in two other diabetic models, the glucokinase knockout heterozygote mouse (Grupe et al, Cell 83:69-78 ( 1995)) and the IFN-α transgenic mouse (Stewart et al, Science 260: 1942-6 ( 1993)). Comparison of peripheral lymphocytes and blood glucose in db/db mice, their appropriate controls and the high glucose models illustrated no relationship between blood-glucose and lymphocyte counts (Fig. 14). These results suggest therefore that the lymphoid defects observed in the db/db mouse are directly attributed to the hematopoietic function ofthe OB protein signalling pathway. To test the capacity ofthe db/db hematopoietic compartment to respond to challenge, the db/db mice and controls were subjected to sub-lethal irradiation C57BLKS/J db/db, C57BLKS/Jm + /db, and C57BLKS/J + m/ + m mice were subjected to sub-lethal whole body irradiation (750 cGy, 190 cGy/min) as a single dose from a Cs source. Ten animals were used per experimental group. The kinetics of hematopoietic recovery were then followed by monitoring the peripheral blood during the recovery phase. This experiment illustrated the inability ofthe db/db hematopoietic system to fully recover the lymphopoietic compartment of the peripheral blood 35 days post-irradiation. Platelet levels in these mice followed the same recovery kinetics as controls, however the reduction in erythrocytes lagged behind controls by 7-10 days. This finding may reflect the increased TER 1 19 population found in the marrow ofthe db/db mice (Fig. 12A). Materials and Methods Bone marrow, spleens and peripheral blood was harvested from the diabetic mouse strains: C57BLKS/J db/db (mutant), C57BLKS/J m+/db (lean heterozygote control littermate), C57BLKS/J+m/+m (lean homozygote misty gray coat control littermate) and the obese mouse strains: C57BLI6i-ob/ob (mutant) and the C57BL/6J- ob/+ (lean littermate control). All strains from the Jackson Laboratory, Bar Harbor, ME. A minimum of five animals were used per experimental group. Femurs were flushed with Hank's balanced salt solution (HBSS) plus 2% FCS and a single cell suspension was made ofthe bone marrow cells. Spleens were harvested and the splenic capsule was ruptured and filtered through a nylon mesh. Peripheral blood was collected through the retro-orbital sinus in phosphate buffered saline (PBS) with lOU/ L heparin and Immol EDTA and processed as previously described. The bone marrow, splenocytes and peripheral blood were then stained with the monoclonal antibodies against the following antigens: B220/CD45R (Pan B cell) FITC antimouse, TER-119/erythroid cell R-PE antimouse, CD4 (L3T4), FITC antimouse, CD8 (Ly 3.2), FITC antimouse, and slgM (lgh-6b), FITC antimouse (All monoclonals from Pharmigen, San Diego, CA). The appropriate isotype controls were included in each experiment. For methylcellulose assays, the bone marrow from five animals per group was pooled and 100,000 cell aliquots from each group used for each assay point. EXAMPLE 11 Expression of OB-immunoadhesin Using protein engineering techniques, the human OB protein was expressed as a fusion with the hinge, CH2 and CH3 domains of IgG 1. DNA constructs encoding the chimera of the human OB protein and IgG 1 Fc domains were made with the Fc region clones of human IgG 1. Human OB cDNA was obtained by PCR from human fat cell dscDNA (Clontech Buick-Clone cDNA product). The source ofthe IgGI cDNA was the plasmid pBSSK-CH2CH3. The chimera contained the coding sequence ofthe full length OB protein (amino acids I - 167 in Figure 16) and human IgG I sequences beginning at aspartic acid 216 (taking amino acid 1 14 as the first residue of the heavy chain constant region (Kabat et al. , Sequences of Proteins of Immunological Interest 4th ed. (1987)), which is the first residue ofthe IgG I hinge after the cysteine residue involved in heavy-light chain bonding, and ending with residues 441 to include the CH2 and CH3 Fc domains of IgG 1. There was an insert of codons for three amino acids (GlyValThr) between the OB protein and IgG 1 coding sequences. If necessary, this short linker sequence can easily be deleted, for example by site directed deletion mutagenesis, to create an exact junction between the coding sequences ofthe OB protein and the IgG 1 hinge region. The coding sequence of the OB-IgGl immunoadhesin was subcloned into the pRK5-based vector pRK5tk-neo which contains a neomycine selectable marker, for transient expression in 293 cells using the calcium phosphate technique (Suva et al, Science 237:893-896 (1987)). 293 cells were cultured in HAM's : Low Glucose DMEM medium (50:50), containing 10% FBS and 2 mM L-Gln. For purification of OB-IgG 1 chimeras, cells were changed to serum free production medium PS24 the day after transfection and media collected after three days. The culture media was filtered. The filtered 293 cell supernatant (400 ml) containing recombinant human OB-IgG 1 was made 1 mM in phenylmethylsulfonyl fluoride and 2 μg/ml in aprotinin. This material was loaded at 4°C onto a 1 x 4.5 cm Protein A agarose column (Pierce catalog # 20365) equilibrated in 100 mM HEPES pH 8. The flow rate was 75 ml h. Once the sample was loaded, the column was washed with equilibration buffer until the A20 reached baseline. The OB-IgG 1 protein was eluted with 3.5 M MgC^ + 2% glycerol (unbuffered) at a flow rate of 15 ml h. The eluate was collected with occasional mixing into 10 ml of 100 mM HEPES pH 8 to reduce the MgC concentration by approximately one-half and to raise me pH. The eluted protein was then dialyzed into phosphate buffered saline, concentrated, sterile filtered and stored either at 4° C or frozen at -70 c C. The OB- IgG 1 immunoadhesin prepared by this method is estimated by SDS-PAGE to be greater than 90% pure. EXAMPLE 12 Preparation of PEG-OB The PEG derivatives ofthe human OB protein were prepared by reaction of hOB protein purified by reverse phase chromatography with a succinimidyl derivative of PEG propionic acid (SPA-PEG) having a nominal molecular weight of 10 kD, which had been obtained from Shearwater Polymers, Inc. (Huntsville, AL). After purification ofthe hOB protein by reverse phase chromatography, an approximately 1-2 mg/ml solution of the protein in 0.1% trifluoroacetic acid and approximately 40% acetonitrile, was diluted with 1/3 to 1/2 volume of 0.2 M borate buffer and the pH adjusted to 8.5 with NaOH. SPA-PEG was added to the reaction mixture to make 1 : 1 and 1 :2 molar ratios of protein to SPA-PEG and the mixture was allowed to incubate at room temperature for one hour. After reaction and purification by gel electrophoresis or ion exchange chromatography, the samples were extensively dialyzed against phosphate-buffered saline and sterilized by filtration through a 0.22 micron filter. Samples were stored at 4°C. Under these conditions, the PEG-hOB resulting from the 1 : 1 molar ratio protein to SPA-PEG reaction consisted primarily of molecules with one 10 kD PEG attached with minor amounts ofthe 2 PEG-containing species. The PEG-hOB from the 1 :2 molar reaction consisted of approximately equal amounts of 2 and 3 PEGs attached to hOB, as determined by SDS gel electrophoresis. In both reactions, small amounts of unreacted protein were also detected. This unreacted protein can be efficiently removed by the gel filtration or ion exchange steps as needed. The PEG derivatives of the human OB protein can also be prepared essentially following the aldehyde chemistry described in EP 372,752 published June 13, 1990. EXAMPLE 13 Murine Agonist Antibodies Mice were immunized five times with 20μg of the WSX receptor immunoadhesin (see Example 2 above) resuspended in MPL-TDM (monophosphoryl lipid A/trehalose dicorynomycolate; Rabi, Immunochemical Research Inc.) into each foot pad. Three days after the last immunization, popliteal lymphoid cells were fused with mouse myeloma cells, X63-Ag8.8.653 cells, using 50% polyethylene glycol as described (Laskov et al. Cell Immunol. 55:251 (1980)). The initial screening of hybridoma culture supernatants was done using a capture ELISA. For the capture ELISA, microtiter plates (Maxisorb; Nunc, Kamstrup, Denmark) were coated with 50μl/well of 2μg/ml of goat antibodies specific to the Fc portion of human IgG (Goat anti-hlgG-Fc; Cappel), in PBS, overnight at 4°C and blocked with 2x BSA for 1 hr at room temperature. Then, 50μl/well of 2μg/ml of WSX receptor immunoadhesin was added to each well for 1 hr. The remaining anti-Fc binding sites were blocked with PBS containing 3% human serum and lOμg/ml of CD4-IgG for 1 hr. Plates were incubated with 50μl/well of 2μg/ml of anti-WSX receptor monoclonal antibody (or hybridoma culture supernatant) for 1 hr. Plates were then incubated wi 50μl/well of HRP-goat anti-mouse IgG. The bound enzyme was detected by the addition of the substrate (OPD) and the plates were read at 490nM with an ELISA plate reader. Between each step, plates were washed in wash buffer (PBS containing 0.05% TWEEN 20™). Agonist antibodies were screened for using the KIRA ELISA described in WO95/I4930. A chimeric receptor comprising the extracellular domain of the WSX receptor and the transmembrane and intracellular domain of Rse receptor (Mark et al. , Journal of Biological Chemistry 269( 14): 10720- 10728 ( 1994)) with a carboxyl-terminal heφes simplex virus glycoprotein D (gD) tag was produced and dpl2.CHO cells were transformed therewith as described in Example 4 of WO95/14930. 4 The WSX/Rse.gD transformed dpl2.CHO cells were seeded (3x 10 per well) in the wells ofa flat- bottom-96 well culture plate in 1 OOμl media and cultured overnight at 37° C in 5% CO2. The following morning the well supernatants were removed and various concentrations of purified mAb were then added to separate wells. The cells were stimulated at 37° C for 30 min. and the well supernatants were decanted. To lyse the cells and solubilize the chimeric receptors, 100 μl of lysis buffer was added to each well. The plate was then agitated gently on a plate shaker (Bellco Instruments, Vineland, NJ) for 60 min. at room temperature. While the cells were being solubihzed, an ELISA microtiter plate (Nunc Maxisoφ, Inter Med, Denmark) coated overnight at 4° C with the 5B6 monoclonal anti-gD antibody (5.0 μg/ml in 50 mM carbonate buffer, pH 9.6, 100 μl/well) was decanted and blocked with 150 μl/well of Block Buffer containing 2% BSA for 60 min. at room temperature. After 60 minutes, the anti-gD 5B6 coated plate was washed 6 times with wash buffer (PBS containing 0.05 % TWEEN 20™ and 0.01 % thimerosal). The lysate containing solubihzed WSX/Rse.gD from the cell-culture microtiter well was transferred (85μl/well) to anti-gD 5B6 coated and blocked ELISA well and was incubated for 2 h at room temperature. The unbound WSX/Rse.gD was removed by washing with wash buffer and 100 μl of biotinylated 4G10 (anti- phosphotyrosine) diluted 1 : 18000 in dilution buffer (PBS containing 0.5 % BSA, 0.05 % Tween-20, 5 mM EDTA, and 0.01 % thimerosal), i.e. 56 ng/ml was added to each well. After incubation for 2 h at room temperature the plate was washed and HRPO-conjugated streptavidin (Zymed Laboratories, S. San Francisco, CA) was added to each well. The plate was incubated for 30 minutes at room temperature with gentle agitation. The free avidin-conjugate was washed away and 100 μl freshly prepared substrate solution (tetramethyl benzidine (TMB); 2-component substrate kit; Kirkegaard and Perry, Gaithersburg, MD) was added to each well. The reaction was allowed to proceed for 10 minutes, after which the color development was stopped by the addition of lOOμl/well 1.0 M H3PO4. The absorbance at 450 nm was read with a reference wavelength of 650 nm ( A ^^45Q^5Q), using a vmax plate reader (Molecular Devices, Palo Alto, CA) controlled with a Macintosh Centris 650 (Apple Computers, Cupertino, CA) and DeltaSoft software (BioMetallics, Inc, Princeton, NJ). Four ofthe 25 anti-WSX receptor monoclonal antibodies activated the chimeric WSX/Rse receptor in the KIRA ELISA. The antibodies were designated: 2D7, 1G4, 1E1 1 and 1C1 1. To determine whether the four agonist anti-WSX receptor mAbs recognized the same or different epitopes, a competitive binding ELISA was performed as described in Kim et al. J. Immunol. Method 156:9- 17 ( 1992) using biotinylated Abs (Bio-mAb) Bio-mAb were prepared using N-hydroxyl succinimide as described in Antibodies A Laboratory Manual Cold Spring Harbor Laboratory, Eds Harlow E and D Lane, p 341 ( 1988) Microtiter wells were coated with 50μl of Goat anti-hlgG-Fc and kept overnight at 4° C, blocked with 2% BSA for 1 hr, and incubated with 25 μl/well of human WSX receptor immunoadhesin (1 μg/ml) for 1 hr at room temperature After washmg, a mixture ofa predetermined optimal concentration of Bio-mAb bound and a thousand-fold excess of unlabeled mAb was added into each well Following lhr incubation at room temperature, plates were washed and the amount of Bio-mAb was detected by the addition of HRP-streptavidin After washing the plates, the bound enzyme was detected by the addition ofthe substrate o-phenylenediamine dihydrochloride (OPD), and the plates were read at 490nm with an ELISA plate reader The ability of the mAbs to recognize murine WSX receptor was determined in a capture ELISA Murine WSX receptor (Fig 21) fused to a gD tag (see above) was captured by an anti-gD (5B6) coated ELISA plate After washing, various concentrations of biotinylated mAbs were added into each well Biotinylated mAbs bound to murine WSX receptor-gD were detected using HRP-streptavidin as described above To determine whether the antibodies bound membrane-bound receptor, FACS analysis was performed using 293 cells transfected with WSX receptor 10 WSX receptor-transfected 293 cells were resuspended in lOOμl of PBS plus 1% fetal calf serum (FSC) and incubated with 2D7 or 1G4 hybridoma cell supernatant for 30 min on ice After washing, cells were incubated with lOOμl of FITC-goat anti-mouse IgG for 30 min at 4°C Cells were washed twice and resuspended in 150μl of PBS plus 1% FCS and analyzed by FACscan (Becton Dickinson, Mountain View, CA) The antibodies 2D7 and 1G4 bound to membrane WSX receptor according to the FACS analysis The properties of agonist antibodies 2D7 and 1G4 are summarized in the following table TABLE 2 mAb Isotype epitope 3 hWSXR b mWSXR b \gonιst c 2D7 IgGI A +++ ++ + 1G4 IgGI B +++ + + a These mAbs are shown to recognize different epitopes by competitive binding ELISA b These results are determined by ELISA (hWSXR is human WSX receptor and mWSXR is murine WSX receptor) c The agonistic activities were determined by KIRA ELISA EXAMPLE 14 Human Agonist Antibodies Single-chain Fv (scFv) fragments binding to the human WSX receptor (hWSXR) were isolated from a large human scFv library (Vaughan et al Nature Biotechnology 14 309-314 (1996)) using antigen coated on immunotubes or biotinylated antigen in conjunction with streptavidin-coated magnetic beads (Griffiths et al EMBO J. 13:3245-3260 (1994); and Vaughan et al. (1996)). Briefly, immunotubes coated overnight with lOμg/ml human WSX receptor immunoadhesin (see Example 2 above) in phosphate buffered saline (PBS) were used for three rounds of panning. The humanized antibody, huMAb4D5-8 (Carter et al. Proc. Natl. Acad. Sci. USA 89:4285-4289 (1992)) was used to counter-select for antibodies binding to the Fc ofthe immunoadhesin. This was done by using lmg ml huMAb4D5-8 in solution for the panning steps. In addition, human WSX receptor extracellular domain (cleaved from the WSX receptor immunoadhesin with Genenase (Carter et al. Proteins: Structure, Function and Genetics 6:240-248 ( 1989)) was biotinylated and used for three rounds of panning. Individual phage following two or three rounds of panning were characterized by antigen-binding ELISA (Tables 3 and 4). TABLE 3 Panning with human WSX receptor immunoadhesin-coatcd immunotubes Phage ELISA # clones # BsfNI Round hWSXR Fc characterized fingeφrints 2 74 / 96 0 / 96 74 l l a 3 191 / 192 1 / 192 58 8 a a Total of 1 1 different clones identified. TABLE 4 Panning with biotinylated human WSX receptor Phage ELISA # clones # BstNI Round hWSXR Fc characterized fingeφrints 2 8 / 96 0 / 96 8 4 a 3 49 / 192 1 / 192 49 4 a a Total of 7 different clones identified. Clones binding to human WSX receptor were further characterized by BstNI fingeφrinting ofa PCR fragment encoding the scFv. A total of 18 clones were identified: 1 1 from the panning using immunotubes and 7 from the panning using biotinylated antigen (there was no overlap between these groups). The DNA for all 18 clones was sequenced. Anti-huWSXR clones obtained as described above were analyzed for agonist activity in a KIRA-ELISA assay (see above and Fig. 22) firstly as scFv phage and then as scFv. The scFv phage were PEG-precipitated (Carter et al, Mutagenesis: A Practical Approach, McPherson, M. ed. IRL Press, Oxford, UK, Chapter I , pp 1-25 (1991)) and resuspended in PBS prior to screening. To prepare the scFv, DNA from the clones was transformed into 33D3 cells (a non-suppressor strain for expression of soluble protein). The cells were plated onto 2YT/2%glucose/50μg per ml of carbenicillin and incubated at 37° C overnight. A 5 ml culture (2YTG: 2YT, 2% glucose, 50μg/ml carbenicillin) was innoculated and grown at 30° C overnight. The next morning, the 5ml culture was diluted into 500ml 2YTG media and grown at 30° C until OD550- 0.3. Then, the media was changed from 2YTG into 2YT/50μg/ml carbenicillin/2mM IPTG and grown at 30° C for 4-5 hrs for scFv production. The culture was harvested and the cell pellet was frozen at -20° C. For purification, the cell pellet was resuspended in 10ml shockate buffer (50mM TrisHCI pH8.5, 20% sucrose, ImM EDTA) and agitated at 4° C for lhr. The debris was spun down and supernatant was taken to be purified on Ni NTA Superose (Qiagen) column. MgC^ was added to the supernatant to 5mM and loaded onto 0.5ml Ni NTA Superose packed into a disposable columnn. The column was then washed with 2x5ml wash buffer 1 (50mM sodium phosphate, 300mM NaCl, 25mM imidazole pH 8.0) followed by 2x5ml wash 2 buffer (50mM sodium phosphate, 300mM NaCl, 50mM imidazole pH 8.0). The scFv was then eluted with 2.5ml elution buffer (50mM sodium phosphate, 300mM NaCl, 250mM imidazole, pH8.0). The eluted pool was buffer exchanged into PBS with a NAP5 column (Pharmacia) and stored at 4°C. Clones #3, #4 and #17 were found to have agonist activity as phage and as scFv (see Figs. 23 and 24). The sequences of these agonist clones are shown in Fig. 25. The activity ofthe antibodies as F(ab')2 in the KIRA ELISA was assessed, with clone #4 and clone 17 showing enhanced activity as F(ab')2. The ability of the antibodies to bind murine WSX receptor in a capture ELISA (see Example 13) was assessed. Clone #4 and clone # 17 bound murine WSX receptor in this assay. SEQUENCE LISTING (1) GENERAL INFORMATION: (i) APPLICANT: GENENTECH, INC. (ii) TITLE OF INVENTION: WSX RECEPTOR AND LIGANDS (iii) NUMBER OF SEQUENCES: 51 (iv) CORRESPONDENCE ADDRESS: (A) ADDRESSEE: Geπentech, Inc. (B) STREET: 460 Point San Bruno Blvd (C) CITY: South San Francisco (D) STATE: California (E) COUNTRY: USA (F) ZIP: 94080 (v) COMPUTER READABLE FORM: (A) MEDIUM TYPE: 3.5 inch, 1.44 Mb floppy disk (B) COMPUTER: IBM PC compatible (C) OPERATING S STEM: PC-DOS/MS-DOS (D) SOFTWARE: WinPatin (Genentech) (vi) CURRENT APPLICATION DATA: (A) APPLICATION NUMBER: (B) FILING DATE: (C) CLASSIFICATION: (vii) PRIOR APPLICATION DATA: (A) APPLICATION NUMBER: 08/667197 (B) FILING DATE: 06/20/96 (vii) PRIOR APPLICATION DATA: (A) APPLICATION NUMBER: 08/585005 (B) FILING DATE: 01/08/96 (viii) ATTORNEY/AGENT INFORMATION: (A) NAME: Lee, Wendy M. (B) REGISTRATION NUMBER: 40,378 (C) REFERENCE/DOCKET NUMBER: P0986P2PCT (ix) TELECOMMUNICATION INFORMATION: (A) TELEPHONE: 415/225-1994 (B) TELEFAX: 415/952-9881 (C) TELEX: 910/371-7168 (2) INFORMATION FOR SEQ ID NO:l: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 4102 base pairs (B) TYPE: Nucleic Acid (c) STRANDEDNESS: Double (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1: GAATTCTCGA GTCGACGGCG GGCGTTAAAG CTCTCGTGGC ATTATCCTTC 50 AGTGGGGCTA TTGGACTGAC TTTTCTTATG CTGGGATGTG CCTTAGAGGA 100 TTATGGGTGT ACTTCTCTGA AGTAAGATGA TTTGTCAAAA ATTCTGTGTG 150 GTTTTGTTAC ATTGGGAATT TATTTATGTG ATAACTGCGT TTAACTTGTC 200 ATATCCAATT ACTCCTTGGA GATTTAAGTT GTCTTGCATG CCACCAAATT 250 CAACCTATGA CTACTTCCTT TTGCCTGCTG GACTCTCAAA GAATACTTCA 300 AATTCGAATG GACATTATGA GACAGCTGTT GAACCTAAGT TTAATTCAAG 350 TGGTACTCAC TTTTCTAACT TATCCAAAAC AACTTTCCAC TGTTGCTTTC 400 GGAGTGAGCA AGATAGAAAC TGCTCCTTAT GTGCAGACAA CATTGAAGGA 450 AAGACATTTG TTTCAACAGT AAATTCTTTA GTTTTTCAAC AAATAGATGC 500 AAACTGGAAC ATACAGTGCT GGCTAAAAGG AGACTTAAAA TTATTCATCT 550 GTTATGTGGA GTCATTATTT AAGAATCTAT TCAGGAATTA TAACTATAAG 600 GTCCATCTTT TATATGTTCT GCCTGAAGTG TTAGAAGATT CACCTCTGGT 650 TCCCCAAAAA GGCAGTTTTC AGATGGTTCA CTGCAATTGC AGTGTTCATG 700 AATGTTGTGA ATGTCTTGTG CCTGTGCCAA CAGCCAAACT CAACGACACT 750 CTCCTTATGT GTTTGAAAAT CACATCTGGT GGAGTAATTT TCCAGTCACC 800 TCTAATGTCA GTTCAGCCCA TAAATATGGT GAAGCCTGAT CCACCATTAG 850 GTTTGCATAT GGAAATCACA GATGATGGTA ATTTAAAGAT TTCTTGGTCC 900 AGCCCACCAT TGGTACCATT TCCACTTCAA TATCAAGTGA AATATTCAGA 950 GAATTCTACA ACAGTTATCA GAGAAGCTGA CAAGATTGTC TCAGCTACAT 1000 CCCTGCTAGT AGACAGTATA CTTCCTGGGT CTTCGTATGA GGTTCAGGTG 1050 AGGGGCAAGA GACTGGATGG CCCAGGAATC TGGAGTGACT GGAGTACTCC 1100 TCGTGTCTTT ACCACACAAG ATGTCATATA CTTTCCACCT AAAATTCTGA 1150 CAAGTGTTGG GTCTAATGTT TCTTTTCACT GCATCTATAA GAAGGAAAAC 1200 AAGATTGTTC CCTCAAAAGA GATTGTTTGG TGGATGAATT TAGCTGAGAA 1250 AATTCCTCAA AGCCAGTATG ATGTTGTGAG TGATCATGTT AGCAAAGTTA 1300 CTTTTTTCAA TCTGAATGAA ACCAAACCTC GAGGAAAGTT TACCTATGAT 1350 GCAGTGTACT GCTGCAATGA ACATGAATGC CATCATCGCT ATGCTGAATT 1400 ATATGTGATT GATGTCAATA TCAATATCTC ATGTGAAACT GATGGGTACT 1450 TAACTAAAAT GACTTGCAGA TGGTCAACCA GTACAATCCA GTCACTTGCG 1500 GAAAGCACTT TGCAATTGAG GTATCATAGG AGCAGCCTTT ACTGTTCTGA 1550 TATTCCATCT ATTCATCCCA TATCTGAGCC CAAAGATTGC TATTTGCAGA 1600 GTGATGGTTT TTATGAATGC ATTTTCCAGC CAATCTTCCT ATTATCTGGC 1650 TACACAATGT GGATTAGGAT CAATCACTCT CTAGGTTCAC TTGACTCTCC 1700 ACCAACATGT GTCCTTCCTG ATTCTGTGGT GAAGCCACTG CCTCCATCCA 1750 GTGTGAAAGC AGAAATTACT ATAAACATTG GATTATTGAA AATATCTTGG 1800 GAAAAGCCAG TCTTTCCAGA GAATAACCTT CAATTCCAGA TTCGCTATGG 1850 TTTAAGTGGA AAAGAAGTAC AATGGAAGAT GTATGAGGTT TATGATGCAA 1900 AATCAAAATC TGTCAGTCTC CCAGTTCCAG ACTTGTGTGC AGTCTATGCT 1950 GTTCAGGTGC GCTGTAAGAG GCTAGATGGA CTGGGATATT GGAGTAATTG 2000 GAGCAATCCA GCCTACACAG TTGTCATGGA TATAAAAGTT CCTATGAGAG 2050 GACCTGAATT TTGGAGAATA ATTAATGGAG ATACTATGAA AAAGGAGAAA 2100 AATGTCACTT TACTTTGGAA GCCCCTGATG AAAAATGACT CATTGTGCAG 2150 TGTTCAGAGA TATGTGATAA ACCATCATAC TTCCTGCAAT GGAACATGGT 2200 CAGAAGATGT GGGAAATCAC ACGAAATTCA CTTTCCTGTG GACAGAGCAA 2250 GCACATACTG TTACGGTTCT GGCCATCAAT TCAATTGGTG CTTCTGTTGC 2300 AAATTTTAAT TTAACCTTTT CATGGCCTAT GAGCAAAGTA AATATCGTGC 2350 AGTCACTCAG TGCTTATCCT TTAAACAGCA GTTGTGTGAT TGTTTCCTGG 2400 ATACTATCAC CCAGTGATTA CAAGCTAATG TATTTTATTA TTGAGTGGAA 2 50 AAATCTTAAT GAAGATGGTG AAATAAAATG GCTTAGAATC TCTTCATCTG 2500 TTAAGAAGTA TTATATCCAT GATCATTTTA TCCCCATTGA GAAGTACCAG 2550 TTCAGTCTTT ACCCAATATT TATGGAAGGA GTGGGAAAAC CAAAGATAAT 2600 TAATAGTTTC ACTCAAGATG ATATTGAAAA ACACCAGAGT GATGCAGGTT 2650 TATATGTAAT TGTGCCAGTA ATTATTTCCT CTTCCATCTT ATTGCTTGGA 2700 ACATTATTAA TATCACACCA AAGAATGAAA AAGCTATTTT GGGAAGATGT 2750 TCCGAACCCC AAGAATTGTT CCTGGGCACA AGGACTTAAT TTTCAGAAGC 2800 CAGAAACGTT TGAGCATCTT TTTATCAAGC ATACAGCATC AGTGACATGT 2850 GGTCCTCTTC TTTTGGAGCC TGAAACAATT TCAGAAGATA TCAGTGTTGA 2900 TACATCATGG AAAAATAAAG ATGAGATGAT GCCAACAACT GTGGTCTCTC 2950 TACTTTCAAC AACAGATCTT GAAAAGGGTT CTGTTTGTAT TAGTGACCAG 3000 TTCAACAGTG TTAACTTCTC TGAGGCTGAG GGTACTGAGG TAACCTATGA 3050 GGACGAAAGC CAGAGACAAC CCTTTGTTAA ATACGCCACG CTGATCAGCA 3100 ACTCTAAACC AAGTGAAACT GGTGAAGAAC AAGGGCTTAT AAATAGTTCA 3150 GTCACCAAGT GCTTCTCTAG CAAAAATTCT CCGTTGAAGG ATTCTTTCTC 3200 TAATAGCTCA TGGGAGATAG AGGCCCAGGC ATTTTTTATA TTATCAGATC 3250 AGCATCCCAA CATAATTTCA CCACACCTCA CATTCTCAGA AGGATTGGAT 3300 GAACTTTTGA AATTGGAGGG AAATTTCCCT GAAGAAAATA ATGATAAAAA 3350 GTCTATCTAT TATTTAGGGG TCACCTCAAT CAAAAAGAGA GAGAGTGGTG 3400 TGCTTTTGAC TGACAAGTCA AGGGTATCGT GCCCATTCCC AGCCCCCTGT 3450 TTATTCACGG ACATCAGAGT TCTCCAGGAC AGTTGCTCAC ACTTTGTAGA 3500 AAATAATATC AACTTAGGAA CTTCTAGTAA GAAGACTTTT GCATCTTACA 3550 TGCCTCAATT CCAAACTTGT TCTACTCAGA CTCATAAGAT CATGGAAAAC 3600 AAGATGTGTG ACCTAACTGT GTAATTTCAC TGAAGAAACC TTCAGATTTG 3650 TGTTATAATG GGTAATATAA AGTGTAATAG ATTATAGTTG TGGGTGGGAG 3700 AGAGAAAAGA AACCAGAGTC AAATTTGAAA ATAATTGTTC CAAATGAATG 3750 TTGTCTGTTT GTTCTCTCTT AGTAACATAG ACAAAAAATT TGAGAAAGCC 3800 TTCATAAGCC TACCAATGTA GACACGCTCT TCTATTTTAT TCCCAAGCTC 3850 TAGTGGGAAG GTCCCTTGTT TCCAGCTAGA AATAAGCCCA ACAGACACCA 3900 TCTTTTGTGA GATGTAATTG TTTTTTCAGA GGGCGTGTTG TTTTACCTCA 3950 AGTTTTTGTT TTGTACCAAC ACACACACAC ACACACATTC TTAACACATG 4000 TCCTTGTGTG TTTTGAGAGT ATATTATGTA TTTATATTTT GTGCTATCAG 4050 ACTGTAGGAT TTGAAGTAGG ACTTTCCTAA ATGTTTAAGA TAAACAGAAT 4100 TC 4102 (2) INFORMATION FOR SEQ ID NO:2: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 1165 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2 : Met He Cys Gin Lys Phe Cys Val Val Leu Leu His Trp Glu Phe 1 5 10 15 He Tyr Val He Thr Ala Phe Asn Leu Ser Tyr Pro He Thr Pro 20 25 30 Trp Arg Phe Lys Leu Ser Cys Met Pro Pro Asn Ser Thr Tyr Asp 35 40 45 Tyr Phe Leu Leu Pro Ala Gly Leu Ser Lys Asn Thr Ser Asn Ser 50 55 60 Asn Gly His Tyr Glu Thr Ala Val Glu Pro Lys Phe Asn Ser Ser 65 70 75 Gly Thr His Phe Ser Asn Leu Ser Lys Thr Thr Phe His Cys Cys 80 85 90 Phe Arg Ser Glu Gin Asp Arg Asn Cys Ser Leu Cys Ala Asp Asn 95 100 105 He Glu Gly Lys Thr Phe Val Ser Thr Val Asn Ser Leu Val Phe 110 115 120 Gin Gin He Asp Ala Asn Trp Asn He Gin Cys Trp Leu Lys Gly 125 130 135 Asp Leu Lys Leu Phe He Cys Tyr Val Glu Ser Leu Phe Lys Asn 140 145 150 Leu Phe Arg Asn Tyr Asn Tyr Lys Val His Leu Leu Tyr Val Leu 155 160 165 Pro Glu Val Leu Glu Asp Ser Pro Leu Val Pro Gin Lys Gly Ser 170 175 180 Phe Gin Met Val His Cys Asn Cys Ser Val His Glu Cys Cys Glu 185 190 195 Cys Leu Val Pro Val Pro Thr Ala Lys Leu Asn Asp Thr Leu Leu 200 205 210 Met Cys Leu Lys He Thr Ser Gly Gly Val He Phe Gin Ser Pro 215 220 225 Leu Met Ser Val Gin Pro He Asn Met Val Lys Pro Asp Pro Pro 230 235 240 Leu Gly Leu His Met Glu He Thr Asp Asp Gly Asn Leu Lys He 245 250 255 Ser Trp Ser Ser Pro Pro Leu Val Pro Phe Pro Leu Gin Tyr Gin 260 265 270 Val Lys Tyr Ser Glu Asn Ser Thr Thr Val He Arg Glu Ala Asp 275 280 285 Lys He Val Ser Ala Thr Ser Leu Leu Val Asp Ser He Leu Pro 290 295 300 Gly Ser Ser Tyr Glu Val Gin Val Arg Gly Lys Arg Leu Asp Gly 305 310 315 Pro Gly He Trp Ser Asp Trp Ser Thr Pro Arg Val Phe Thr Thr 320 325 330 Gin Asp Val He Tyr Phe Pro Pro Lys He Leu Thr Ser Val Gly 335 340 345 Ser Asn Val Ser Phe His Cys He Tyr Lys Lys Glu Asn Lys He 350 355 360 Val Pro Ser Lys Glu He Val Trp Trp Met Asn Leu Ala Glu Lys 365 370 375 He Pro Gin Ser Gin Tyr Asp Val Val Ser Asp His Val Ser Lys 380 385 390 Val Thr Phe Phe Asn Leu Asn Glu Thr Lys Pro Arg Gly Lys Phe 395 400 405 Thr Tyr Asp Ala Val Tyr Cys Cys Asn Glu His Glu Cys. His His 410 415 420 Arg Tyr Ala Glu Leu Tyr Val He Asp Val Asn He Asn He Ser 425 430 435 Cys Glu Thr Asp Gly Tyr Leu Thr Lys Met Thr Cys Arg Trp Ser 440 445 450 Thr Ser Thr He Gin Ser Leu Ala Glu Ser Thr Leu Gin Leu Arg 455 460 465 Tyr His Arg Ser Ser Leu Tyr Cys Ser Asp He Pro Ser He His 470 475 480 Pro He Ser Glu Pro Lys Asp Cys Tyr Leu Gin Ser Asp Gly Phe 485 490 495 Tyr Glu Cys He Phe Gin Pro He Phe Leu Leu Ser Gly Tyr Thr 500 505 510 Met Trp He Arg He Asn His Ser Leu Gly Ser Leu Asp Ser Pro 515 520 525 Pro Thr Cys Val Leu Pro Asp Ser Val Val Lys Pro Leu Pro Pro 530 535 540 Ser Ser Val Lys Ala Glu He Thr He Asn He Gly Leu Leu Lys 545 550 555 He Ser Trp Glu Lys Pro Val Phe Pro Glu Asn Asn Leu Gin Phe 560 565 570 Gin He Arg Tyr Gly Leu Ser Gly Lys Glu Val Gin Trp Lys Met 575 580 585 Tyr Glu Val Tyr Asp Ala Lys Ser Lys Ser Val Ser Leu Pro Val 590 595 600 Pro Asp Leu Cys Ala Val Tyr Ala Val Gin Val Arg Cys Lys Arg 605 610 615 Leu Asp Gly Leu Gly Tyr Trp Ser Asn Trp Ser Asn Pro Ala Tyr 620 625 630 Thr Val Val Met Asp He Lys Val Pro Met Arg Gly Pro Glu Phe 635 640 645 Trp Arg He He Asn Gly Asp Thr Met Lys Lys Glu Lys Asn Val 650 655 660 Thr Leu Leu Trp Lys Pro Leu Met Lys Asn Asp Ser Leu Cys Ser 665 670 675 Val Gin Arg Tyr Val He Asn His His Thr Ser Cys Asn Gly Thr 680 685 690 Trp Ser Glu Asp Val Gly Asn His Thr Lys Phe Thr Phe Leu Trp 695 700 705 Thr Glu Gin Ala His Thr Val Thr Val Leu Ala He Asn Ser He 710 715 720 Gly Ala Ser Val Ala Asn Phe Asn Leu Thr Phe Ser Trp Pro Met 725 730 735 Ser Lys Val Asn He Val Gin Ser Leu Ser Ala Tyr Pro Leu Asn 740 745 750 Ser Ser Cys Val He Val Ser Trp He Leu Ser Pro Ser Asp Tyr 755 760 765 Lys Leu Met Tyr Phe He He Glu Trp Lys Asn Leu Asn Glu Asp 770 775 780 Gly Glu He Lys Trp Leu Arg He Ser Ser Ser Val Lys Lys Tyr 785 790 795 Tyr He His Asp His Phe He Pro He Glu Lys Tyr Gin Phe Ser 800 805 810 Leu Tyr Pro He Phe Met Glu Gly Val Gly Lys Pro Lys He He 815 820 825 Asn Ser Phe Thr Gin Asp Asp He Glu Lys His Gin Ser Asp Ala 830 835 840 Gly Leu Tyr Val He Val Pro Val He He Ser Ser Ser He Leu 845 850 855 Leu Leu Gly Thr Leu Leu He Ser His Gin Arg Met Lys Lys Leu 860 865 870 Phe Trp Glu Asp Val Pro Asn Pro Lys Asn Cys Ser Trp Ala Gin 875 880 885 Gly Leu Asn Phe Gin Lys Pro Glu Thr Phe Glu His Leu Phe He 890 895 900 Lys His Thr Ala Ser Val Thr Cys Gly Pro Leu Leu Leu Glu Pro 905 910 915 Glu Thr He Ser Glu Asp He Ser Val Asp Thr Ser Trp Lys Asn 920 925 930 Lys Asp Glu Met Met Pro Thr Thr Val Val Ser Leu Leu Ser Thr 935 940 945 Thr Asp Leu Glu Lys Gly Ser Val Cys He Ser Asp Gin Phe Asn 950 955 960 Ser Val Asn Phe Ser Glu Ala Glu Gly Thr Glu Val Thr Tyr Glu 965 970 975 Asp Glu Ser Gin Arg Gin Pro Phe Val Lys Tyr Ala Thr Leu He 980 985 990 Ser Asn Ser Lys Pro Ser Glu Thr Gly Glu Glu Gin Gly Leu He 995 1000 1005 Asn Ser Ser Val Thr Lys Cys Phe Ser Ser Lys Asn Ser Pro Leu 1010 1015 1020 Lys Asp Ser Phe Ser Asn Ser Ser Trp Glu He Glu Ala Gin Ala 1025 1030 1035 Phe Phe He Leu Ser Asp Gin His Pro Asn He He Ser Pro His 1040 1045 1050 Leu Thr Phe Ser Glu Gly Leu Asp Glu Leu Leu Lys Leu Glu Gly 1055 1060 1065 Asn Phe Pro Glu Glu Asn Asn Asp Lys Lys Ser He Tyr Tyr Leu 1070 1075 1080 Gly Val Thr Ser He Lys Lys Arg Glu Ser Gly Val Leu Leu Thr 1085 1090 1095 Asp Lys Ser Arg Val Ser Cys Pro Phe Pro Ala Pro Cys Leu Phe 1100 1105 1110 Thr Asp He Arg Val Leu Gin Asp Ser Cys Ser His Phe Val Glu 1115 1120 1125 Asn Asn He Asn Leu Gly Thr Ser Ser Lys Lys Thr Phe Ala Ser 1130 1135 1140 Tyr Met Pro Gin Phe Gin Thr Cys Ser Thr Gin Thr His Lys He 1145 1150 1155 Met Glu Asn Lys Met Cys Asp Leu Thr Val 1160 1165 (2) INFORMATION FOR SEQ ID NO:3: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 896 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3 : Met He Cys Gin Lys Phe Cys Val Val Leu Leu His Trp Glu Phe 1 5 10 15 He Tyr Val He Thr Ala Phe Asn Leu Ser Tyr Pro He Thr Pro 20 25 30 Trp Arg Phe Lys Leu Ser Cys Met Pro Pro Asn Ser Thr Tyr Asp 35 40 45 Tyr Phe Leu Leu Pro Ala Gly Leu Ser Lys Asn Thr Ser Asn Ser 50 55 60 Asn Gly His Tyr Glu Thr Ala Val Glu Pro Lys Phe Asn Ser Ser 65 70 75 Gly Thr His Phe Ser Asn Leu Ser Lys Thr Thr Phe His Cys Cys 80 85 90 Phe Arg Ser Glu Gin Asp Arg Asn Cys Ser Leu Cys Ala Asp Asn 95 100 105 He Glu Gly Lys Thr Phe Val Ser Thr Val Asn Ser Leu Val Phe 110 115 120 Gin Gin He Asp Ala Asn Trp Asn He Gin Cys Trp Leu Lys Gly 125 130 135 Asp Leu Lys Leu Phe He Cys Tyr Val Glu Ser Leu Phe Lys Asn 140 145 150 Leu Phe Arg Asn Tyr Asn Tyr Lys Val His Leu Leu Tyr Val Leu 155 160 165 Pro Glu Val Leu Glu Asp Ser Pro Leu Val Pro Gin Lys Gly Ser 170 175 180 Phe Gin Met Val His Cys Asn Cys Ser Val His Glu Cys Cys Glu 185 190 195 Cys Leu Val Pro Val Pro Thr Ala Lys Leu Asn Asp Thr Leu Leu 200 205 210 Met Cys Leu Lys He Thr Ser Gly Gly Val He Phe Gin Ser Pro 215 220 225 Leu Met Ser Val Gin Pro He Asn Met Val Lys Pro Asp Pro Pro 230 235 240 Leu Gly Leu His Met Glu He Thr Asp Asp Gly Asn Leu Lys He 245 250 255 Ser Trp Ser Ser Pro Pro Leu Val Pro Phe Pro Leu Gin Tyr Gin 260 265 270 Val Lys Tyr Ser Glu Asn Ser Thr Thr Val He Arg Glu Ala Asp 275 280 285 Lys He Val Ser Ala Thr Ser Leu Leu Val Asp Ser He Leu Pro 290 295 300 Gly Ser Ser Tyr Glu Val Gin Val Arg Gly Lys Arg Leu Asp Gly 305 310 315 Pro Gly He Trp Ser Asp Trp Ser Thr Pro Arg Val Phe Thr Thr 320 325 330 Gin Asp Val He Tyr Phe Pro Pro Lys He Leu Thr Ser Val Gly 335 340 345 Ser Asn Val Ser Phe His Cys He Tyr Lys Lys Glu Asn Lys He 350 355 360 Val Pro Ser Lys Glu He Val Trp Trp Met Asn Leu Ala Glu Lys 365 370 375 He Pro Gin Ser Gin Tyr Asp Val Val Ser Asp His Val Ser Lys 380 385 390 Val Thr Phe Phe Asn Leu Asn Glu Thr Lys Pro Arg Gly Lys Phe 395 400 405 Thr Tyr Asp Ala Val Tyr Cys Cys Asn Glu His Glu Cys His His 410 415 420 Arg Tyr Ala Glu Leu Tyr Val He Asp Val Asn He Asn He Ser 425 430 435 Cys Glu Thr Asp Gly Tyr Leu Thr Lys Met Thr Cys Arg Trp Ser 440 445 450 Thr Ser Thr He Gin Ser Leu Ala Glu Ser Thr Leu Gin Leu Arg 455 460 465 Tyr His Arg Ser Ser Leu Tyr Cys Ser Asp He Pro Ser He His 470 475 480 Pro He Ser Glu Pro Lys Asp Cys Tyr Leu Gin Ser Asp Gly Phe 485 490 495 Tyr Glu Cys He Phe Gin Pro He Phe Leu Leu Ser Gly Tyr Thr 500 505 510 Met Trp He Arg He Asn His Ser Leu Gly Ser Leu Asp Ser Pro 515 520 525 Pro Thr Cys Val Leu Pro Asp Ser Val Val Lys Pro Leu Pro Pro 530 535 540 Ser Ser Val Lys Ala Glu He Thr He Asn He Gly Leu Leu Lys 545 550 555 He Ser Trp Glu Lys Pro Val Phe Pro Glu Asn Asn Leu Gin Phe 560 565 570 Gin He Arg Tyr Gly Leu Ser Gly Lys Glu Val Gin Trp Lys Met 575 580 585 Tyr Glu Val Tyr Asp Ala Lys Ser Lys Ser Val Ser Leu Pro Val 590 595 600 Pro Asp Leu Cys Ala Val Tyr Ala Val Gin Val Arg Cys Lys Arg 605 610 615 Leu Asp Gly Leu Gly Tyr Trp Ser Asn Trp Ser Asn Pro Ala Tyr 620 625 630 Thr Val Val Met Asp He Lys Val Pro Met Arg Gly Pro Glu Phe 635 640 645 Trp Arg He He Asn Gly Asp Thr Met Lys Lys Glu Lys Asn Val 650 655 660 Thr Leu Leu Trp Lys Pro Leu Met Lys Asn Asp Ser Leu Cys Ser 665 670 675 Val Gin Arg Tyr Val He Asn His His Thr Ser Cys Asn Gly Thr 680 685 690 Trp Ser Glu Asp Val Gly Asn His Thr Lys Phe Thr Phe Leu Trp 695 700 705 Thr Glu Gin Ala His Thr Val Thr Val Leu Ala He Asn Ser He 710 715 720 Gly Ala Ser Val Ala Asn Phe Asn Leu Thr Phe Ser Trp Pro Met 725 730 735 Ser Lys Val Asn He Val Gin Ser Leu Ser Ala Tyr Pro Leu Asn 740 745 750 Ser Ser Cys Val He Val Ser Trp He Leu Ser Pro Ser Asp Tyr 755 760 765 Lys Leu Met Tyr Phe He He Glu Trp Lys Asn Leu Asn Glu Asp 770 775 780 Gly Glu He Lys Trp Leu Arg He Ser Ser Ser Val Lys Lys Tyr 785 790 795 Tyr He His Asp His Phe He Pro He Glu Lys Tyr Gin Phe Ser 800 805 810 Leu Tyr Pro He Phe Met Glu Gly Val Gly Lys Pro Lys He He 815 820 825 Asn Ser Phe Thr Gin Asp Asp He Glu Lys His Gin Ser Asp Ala 830 835 840 Gly Leu Tyr Val He Val Pro Val He He Ser Ser Ser He Leu 845 850 855 Leu Leu Gly Thr Leu Leu He Ser His Gin Arg Met Lys Lys Leu 860 865 870 Phe Trp Glu Asp Val Pro Asn Pro Lys Asn Cys Ser Trp Ala Gin 875 880 885 Gly Leu Asn Phe Gin Lys Arg Thr Asp He Leu 890 895 896 (2) INFORMATION FOR SEQ ID NO:4: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 923 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4 : Met He Cys Gin Lys Phe Cys Val Val Leu Leu His Trp Glu Phe l 5 10 15 He Tyr Val He Thr Ala Phe Asn Leu Ser Tyr Pro He Thr Pro 20 25 30 Trp Arg Phe Lys Leu Ser Cys Met Pro Pro Asn Ser Thr Tyr Asp 35 40 45 Tyr Phe Leu Leu Pro Ala Gly Leu Ser Lys Asn Thr Ser Asn Ser 50 55 60 Asn Gly His Tyr Glu Thr Ala Val Glu Pro Lys Phe Asn Ser Ser 65 70 75 Gly Thr His Phe Ser Asn Leu Ser Lys Thr Thr Phe His Cys Cys 80 85 90 Phe Arg Ser Glu Gin Asp Arg Asn Cys Ser Leu Cys Ala Asp Asn 95 100 105 He Glu Gly Lys Thr Phe Val Ser Thr Val Asn Ser Leu Val Phe 110 115 120 Gin Gin He Asp Ala Asn Trp Asn He Gin Cys Trp Leu Lys Gly 125 130 135 Asp Leu Lys Leu Phe He Cys Tyr Val Glu Ser Leu Phe Lys Asn 140 145 150 Leu Phe Arg Asn Tyr Asn Tyr Lys Val His Leu Leu Tyr Val Leu 155 160 165 Pro Glu Val Leu Glu Asp Ser Pro Leu Val Pro Gin Lys Gly Ser 170 175 180 Phe Gin Met Val His Cys Asn Cys Ser Val His Glu Cys Cys Glu 185 190 195 Cys Leu Val Pro Val Pro Thr Ala Lys Leu Asn Asp Thr Leu Leu 200 205 210 Met Cys Leu Lys He Thr Ser Gly Gly Val He Phe Gin Ser Pro 215 220 225 Leu Met Ser Val Gin Pro He Asn Met Val Lys Pro Asp Pro Pro 230 235 240 Leu Gly Leu His Met Glu He Thr Asp Asp Gly Asn Leu Lys He 245 250 255 Ser Trp Ser Ser Pro Pro Leu Val Pro Phe Pro Leu Gin Tyr Gin 260 265 270 Val Lys Tyr Ser Glu Asn Ser Thr Thr Val He Arg Glu Ala Asp 275 280 285 Lys He Val Ser Ala Thr Ser Leu Leu Val Asp Ser He Leu Pro 290 295 300 Gly Ser Ser Tyr Glu Val Gin Val Arg Gly Lys Arg Leu Asp Gly 305 310 315 Pro Gly He Trp Ser Asp Trp Ser Thr Pro Arg Val Phe Thr Thr 320 325 330 Gin Asp Val He Tyr Phe Pro Pro Lys He Leu Thr Ser Val Gly 335 340 345 Ser Asn Val Ser Phe His Cys He Tyr Lys Lys Glu Asn Lys He 350 355 360 Val Pro Ser Lys Glu He Val Trp Trp Met Asn Leu Ala Glu Lys 365 370 375 He Pro Gin Ser Gin Tyr Asp Val Val Ser Asp His Val Ser Lys 380 385 390 Val Thr Phe Phe Asn Leu Asn Glu Thr Lys Pro Arg Gly Lys Phe 395 400 405 Thr Tyr Asp Ala Val Tyr Cys Cys Asn Glu His Glu Cys His His 410 415 420 Arg Tyr Ala Glu Leu Tyr Val He Asp Val Asn He Asn He Ser 425 430 435 Cys Glu Thr Asp Gly Tyr Leu Thr Lys Met Thr Cys Arg Trp Ser 440 445 450 Thr Ser Thr He Gin Ser Leu Ala Glu Ser Thr Leu Gin Leu Arg 455 460 465 Tyr His Arg Ser Ser Leu Tyr Cys Ser Asp He Pro Ser He His 470 475 480 Pro He Ser Glu Pro Lys Asp Cys Tyr Leu Gin Ser Asp Gly Phe 485 490 495 Tyr Glu Cys He Phe Gin Pro He Phe Leu Leu Ser Gly Tyr Thr 500 505 510 Met Trp He Arg He Asn His Ser Leu Gly Ser Leu Asp Ser Pro 515 520 525 Pro Thr Cys Val Leu Pro Asp Ser Val Val Lys Pro Leu Pro Pro 530 535 540 Ser Ser Val Lys Ala Glu He Thr He Asn He Gly Leu Leu Lys 545 550 555 He Ser Trp Glu Lys Pro Val Phe Pro Glu Asn Asn Leu Gin Phe 560 565 570 Gin He Arg Tyr Gly Leu Ser Gly Lys Glu Val Gin Trp Lys Met 575 580 585 Tyr Glu Val Tyr Asp Ala Lys Ser Lys Ser Val Ser Leu Pro Val 590 595 600 Pro Asp Leu Cys Ala Val Tyr Ala Val Gin Val Arg Cys Lys Arg 605 610 615 Leu Asp Gly Leu Gly Tyr Trp Ser Asn Trp Ser Asn Pro Ala Tyr 620 625 630 Thr Val Val Met Asp He Lys Val Pro Met Arg Gly Pro Glu Phe 635 640 645 Trp Arg He He Asn Gly Asp Thr Met Lys Lys Glu Lys Asn Val 650 655 660 Thr Leu Leu Trp Lys Pro Leu Met Lys Asn Asp Ser Leu Cys Ser 665 670 675 Val Gin Arg Tyr Val He Asn His His Thr Ser Cys Asn Gly Thr 680 685 690 Trp Ser Glu Asp Val Gly Asn His Thr Lys Phe Thr Phe Leu Trp 695 700 705 Thr Glu Gin Ala His Thr Val Thr Val Leu Ala He Asn Ser He 710 715 720 Gly Ala Ser Val Ala Asn Phe Asn Leu Thr Phe Ser Trp Pro Met 725 730 735 Ser Lys Val Asn He Val Gin Ser Leu Ser Ala Tyr Pro Leu Asn 740 745 750 Ser Ser Cys Val He Val Ser Trp He Leu Ser Pro Ser Asp Tyr 755 760 765 Lys Leu Met Tyr Phe He He Glu Trp Lys Asn Leu Asn Glu Asp 770 775 780 Gly Glu He Lys Trp Leu Arg He Ser Ser Ser Val Lys Lys Tyr 785 790 795 Tyr He His Asp His Phe He Pro He Glu Lys Tyr Gin Phe Ser 800 805 810 Leu Tyr Pro He Phe Met Glu Gly Val Gly Lys Pro Lys He He 815 820 825 Asn Ser Phe Thr Gin Asp Asp He Glu Lys His Gin Ser Asp Ala 830 835 840 Gly Leu Tyr Val He Val Pro Val He He Ser Ser Ser He Leu 845 850 855 Leu Leu Gly Thr Leu Leu He Ser His Gin Arg Met Lys Lys Leu 860 865 870 Phe Trp Glu Asp Val Pro Asn Pro Lys Asn Cys Ser Trp Ala Gin 875 880 885 Gly Leu Asn Phe Gin Lys Met Phe Arg Thr Pro Arg He Val Pro 890 895 900 Gly His Lys Asp Leu He Phe Arg Arg Cys Leu Lys Ala Ala Cys 905 910 915 Ser Leu Arg Val He Thr Thr Pro 920 923 (2) INFORMATION FOR SEQ ID NO:5: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 3004 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5: GAATTCCGGG TTAAAGCTCT CGTGGCATTA TCCTTCAGTG GGGCTATTGG 50 ACTGACTTTT CTTATGCTGG GATGTGCCTT AGAGGATTAT GGATTTGCCA 100 GTTCACCCTG ACCATCTTGA AAATAAGTTA TCTCTGATCT CTGTCTGTAT 150 GTTACTTCTC TCCCCTCACC AATGGAGAAC AAATGTGGGC AAAGTGTACT 200 TCTCTGAAGT AAGATGATTT GTCAAAAATT CTGTGTGGTT TTGTTACATT 250 GGGAATTTAT TTATGTGATA ACTGCGTTTA ACTTGTCATA TCCAATTACT 300 CCTTGGAGAT TTAAGTTGTC TTGCATGCCA CCAAATTCAA CCTATGACTA 350 CTTCCTTTTG CCTGCTGGAC TCTCAAAGAA TACTTCAAAT TCGAATGGAC 400 ATTATGAGAC AGCTGTTGAA CCTAAGTTTA ATTCAAGTGG TACTCACTTT 450 TCTAACTTAT CCAAAACAAC TTTCCACTGT TGCTTTCGGA GTGAGCAAGA 500 TAGAAACTGC TCCTTATGTG CAGACAACAT TGAAGGAAAG ACATTTGTTT 550 CNACAGTAAA TTCTTTAGTT TTTCAACAAA TAGATGCAAA CTGGAACATA 600 CAGTGCTGGC TAAAAGGAGA CTTAAAATTA TTCATCTGTT ATGTGGAGTC 650 ATTATTTAAG AATCTATTCA GGAATTATAA CTATAAGGTC CATCTTTTAT 700 ATGTTCTGCC TGAAGTGTTA GAAGATTCAC CTCTGGTTCC CCAAAAAGGC 750 AGTTTTCAGA TGGTTCACTG CAATTGCAGT GTTCATGAAT GTTGTGAATG 800 TCTTGTGCCT GTGCCAACAG CCAAACTCAA CGACACTCTC CTTATGTGTT 850 TGAAAATCAC ATCTGGTGGA GTAATTTTCC AGTCACCTCT AATGTCAGTT 900 CAGCCCATAA ATATGGTGAA GCCTGATCCA CCATTAGGTT TGCATATGGA 950 AATCACAGAT GATGGTAATT TAAAGATTTC TTGGTCCAGC CCACCATTGG 1000 TACCATTTCC ACTTCAATAT CAAGTGAAAT ATTCAGAGAA TTCTACAACA 1050 GTTATCAGAG AAGCTGACAA GATTGTCTCA GCTACATCCC TGCTAGTAGA 1100 CAGTATACTT CCTGGGTCTT CGTATGAGGT TCAGGTGAGG GGCAAGAGAC 1150 TGGATGGCCC AGGAATCTGG AGTGACTGGA GTACTCCTCG TGTCTTTACC 1200 ACACAAGATG TCATATACTT TCCACCTAAA ATTCTGACAA GTGTTGGGTC 1250 TAATGTTTCT TTTCACTGCA TCTATAAGAA GGAAAACAAG ATTGTTCCCT 1300 CAAAAGAGAT TGTTTGGTGG ATGAATTTAG CTGAGAAAAT TCCTCAAAGC 1350 CAGTATGATG TTGTGAGTGA TCATGTTAGC AAAGTTACTT TTTTCAATCT 1400 GAATGAAACC AAACCTCGAG GAAAGTTTAC CTATGATGCA GTGTACTGCT 1450 GCAATGAACA TGAATGCCAT CATCGCTATG CTGAATTATA TGTGATTGAT 1500 GTCAATATCA ATATCTCATG TGAAACTGAT GGGTACTTAA CTAAAATGAC 1550 TTGCAGATGG TCAACCAGTA CAATCCAGTC ACTTGCGGAA AGCACTTTGC 1600 AATTGAGGTA TCATAGGAGC AGCCTTTACT GTTCTGATAT TCCATCTATT 1650 CATCCCATAT CTGAGCCCAA AGATTGCTAT TTGCAGAGTG ATGGTTTTTA 1700 TGAATGCATT TTCCAGCCAA TCTTCCTATT ATCTGGCTAC ACAATGTGGA 1750 TTAGGATCAA TCACTCTCTA GGTTCACTTG ACTCTCCACC AACATGTGTC 1800 CTTCCTGATT CTGTGGTGAA GCCACTGCCT CCATCCAGTG TGAAAGCAGA 1850 AATTACTATA AACATTGGAT TATTGAAAAT ATCTTGGGAA AAGCCAGTCT 1900 TTCCAGAGAA TAACCTTCAA TTCCAGATTC GCTATGGTTT AAGTGGAAAA 1950 GAAGTACAAT GGAAGATGTA TGAGGTTTAT GATGCAAAAT CAAAATCTGT 2000 CAGTCTCCCA GTTCCAGACT TGTGTGCAGT CTATGCTGTT CAGGTGCGCT 2050 GTAAGAGGCT AGATGGACTG GGATATTGGA GTAATTGGAG CAATCCAGCC 2100 TACACAGTTG TCATGGATAT AAAAGTTCCT ATGAGAGGAC CTGAATTTTG 2150 GAGAATAATT AATGGAGATA CTATGAAAAA GGAGAAAAAT GTCACTTTAC 2200 TTTGGAAGCC CCTGATGAAA AATGACTCAT TGTGCAGTGT TCAGAGATAT 2250 GTGATAAACC ATCATACTTC CTGCAATGGA ACATGGTCAG AAGATGTGGG 2300 AAATCACACG AAATTCACTT TCCTGTGGAC AGAGCAAGCA CATACTGTTA 2350 CGGTTCTGGC CATCAATTCA ATTGGTGCTT CTGTTGCAAA TTTTAATTTA 2400 ACCTTTTCAT GGCCTATGAG CAAAGTAAAT ATCGTGCAGT CACTCAGTGC 2450 TTATCCTTTA AACAGCAGTT GTGTGATTGT TTCCTGGATA CTATCACCCA 2500 GTGATTACAA GCTAATGTAT TTTATTATTG AGTGGAAAAA TCTTAATGAA 2550 GATGGTGAAA TAAAATGGCT TAGAATCTCT TCATCTGTTA AGAAGTATTA 2600 TATCCATGAT CATTTTATCC CCATTGAGAA GTACCAGTTC AGTCTTTACC 2650 CAATATTTAT GGAAGGAGTG GGAAAACCAA AGATAATTAA TAGTTTCACT 2700 CAAGATGATA TTGAAAAACA CCAGAGTGAT GCAGGTTTAT ATGTAATTGT 2750 GCCAGTAATT ATTTCCTCTT CCATCTTATT GCTTGGAACA TTATTAATAT 2800 CACACCAAAG AATGAAAAAG CTATTTTGGG AAGATGTTCC GAACCCCAAG 2850 AATTGTTCCT GGGCACAAGG ACTTAATTTT CAGAAGAGAA CGGACATTCT 2900 TTGAAGTCTA ATCATGATCA CTACAGATGA ACCCAATGTG CCAACTTCCC 2950 AACAGTCTAT AGAGTATTAG AAGATTTTTA CATTTTGAAG AAGGGCCGGA 3000 ATTC 3004 (2) INFORMATION FOR SEQ ID NO:6 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 3102 base pairs (B) TYPE: Nucleic Acid <C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6: GAATTCTCGA GTCGACGGCG GGCGTTAAAG CTCTCGTGGC ATTATCCTTC 50 AGTGGGGCTA TTGGACTGAC TTTTCTTATG CTGGGATGTG CCTTAGAGGA 100 TTATGGGTGT ACTTCTCTGA AGTAAGATGA TTTGTCAAAA ATTCTGTGTG 150 GTTTTGTTAC ATTGGGAATT TATTTATGTG ATAACTGCGT TTAACTTGTC 200 ATATCCAATT ACTCCTTGGA GATTTAAGTT GTCTTGCATG CCACCAAATT 250 CAACCTATGA CTACTTCCTT TTGCCTGCTG GACTCTCAAA GAATACTTCA 300 AATTCGAATG GACATTATGA GACAGCTGTT GAACCTAAGT TTAATTCAAG 350 TGGTACTCAC TTTTCTAACT TATCCAAAAC AACTTTCCAC TGTTGCTTTC 400 GGAGTGAGCA AGATAGAAAC TGCTCCTTAT GTGCAGACAA CATTGAAGGA 450 AAGACATTTG TTTCAACAGT AAATTCTTTA GTTTTTCAAC AAATAGATGC 500 AAACTGGAAC ATACAGTGCT GGCTAAAAGG AGACTTAAAA TTATTCATCT 550 GTTATGTGGA GTCATTATTT AAGAATCTAT TCAGGAATTA TAACTATAAG 600 GTCCATCTTT TATATGTTCT GCCTGAAGTG TTAGAAGATT CACCTCTGGT 650 TCCCCAAAAA GGCAGTTTTC AGATGGTTCA CTGCAATTGC AGTGTTCATG 700 AATGTTGTGA ATGTCTTGTG CCTGTGCCAA CAGCCAAACT CAACGACACT 750 CTCCTTATGT GTTTGAAAAT CACATCTGGT GGAGTAATTT TCCAGTCACC 800 TCTAATGTCA GTTCAGCCCA TAAATATGGT GAAGCCTGAT CCACCATTAG 850 GTTTGCATAT GGAAATCACA GATGATGGTA ATTTAAAGAT TTCTTGGTCC 900 AGCCCACCAT TGGTACCATT TCCACTTCAA TATCAAGTGA AATATTCAGA 950 GAATTCTACA ACAGTTATCA GAGAAGCTGA CAAGATTGTC TCAGCTACAT 1000 CCCTGCTAGT AGACAGTATA CTTCCTGGGT CTTCGTATGA GGTTCAGGTG 1050 AGGGGCAAGA GACTGGATGG CCCAGGAATC TGGAGTGACT GGAGTACTCC 1100 TCGTGTCTTT ACCACACAAG ATGTCATATA CTTTCCACCT AAAATTCTGA 1150 CAAGTGTTGG GTCTAATGTT TCTTTTCACT GCATCTATAA GAAGGAAAAC 1200 AAGATTGTTC CCTCAAAAGA GATTGTTTGG TGGATGAATT TAGCTGAGAA 1250 AATTCCTCAA AGCCAGTATG ATGTTGTGAG TGATCATGTT AGCAAAGTTA 1300 CTTTTTTCAA TCTGAATGAA ACCAAACCTC GAGGAAAGTT TACCTATGAT 1350 GCAGTGTACT GCTGCAATGA ACATGAATGC CATCATCGCT ATGCTGAATT 1400 ATATGTGATT GATGTCAATA TCAATATCTC ATGTGAAACT GATGGGTACT 1450 TAACTAAAAT GACTTGCAGA TGGTCAACCA GTACAATCCA GTCACTTGCG 1500 GAAAGCACTT TGCAATTGAG GTATCATAGG AGCAGCCTTT ACTGTTCTGA 1550 TATTCCATCT ATTCATCCCA TATCTGAGCC CAAAGATTGC TATTTGCAGA 1600 GTGATGGTTT TTATGAATGC ATTTTCCAGC CAATCTTCCT ATTATCTGGC 1650 TACACAATGT GGATTAGGAT CAATCACTCT CTAGGTTCAC TTGACTCTCC 1700 ACCAACATGT GTCCTTCCTG ATTCTGTGGT GAAGCCACTG CCTCCATCCA 1750 GTGTGAAAGC AGAAATTACT ATAAACATTG GATTATTGAA AATATCTTGG 1800 GAAAAGCCAG TCTTTCCAGA GAATAACCTT CAATTCCAGA TTCGCTATGG 1850 TTTAAGTGGA AAAGAAGTAC AATGGAAGAT GTATGAGGTT TATGATGCAA 1900 AATCAAAATC TGTCAGTCTC CCAGTTCCAG ACTTGTGTGC AGTCTATGCT 1950 GTTCAGGTGC GCTGTAAGAG GCTAGATGGA CTGGGATATT GGAGTAATTG 2000 GAGCAATCCA GCCTACACAG TTGTCATGGA TATAAAAGTT CCTATGAGAG 2050 GACCTGAATT TTGGAGAATA ATTAATGGAG ATACTATGAA AAAGGAGAAA 2100 AATGTCACTT TACTTTGGAA GCCCCTGATG AAAAATGACT CATTGTGCAG 2150 TGTTCAGAGA TATGTGATAA ACCATCATAC TTCCTGCAAT GGAACATGGT 2200 CAGAAGATGT GGGAAATCAC ACGAAATTCA CTTTCCTGTG GACAGAGCAA 2250 GCACATACTG TTACGGTTCT GGCCATCAAT TCAATTGGTG CTTCTGTTGC 2300 AAATTTTAAT TTAACCTTTT CATGGCCTAT GAGCAAAGTA AATATCGTGC 2350 AGTCACTCAG TGCTTATCCT TTAAACAGCA GTTGTGTGAT TGTTTCCTGG 2400 ATACTATCAC CCAGTGATTA CAAGCTAATG TATTTTATTA TTGAGTGGAA 2450 AAATCTTAAT GAAGATGGTG AAATAAAATG GCTTAGAATC TCTTCATCTG 2500 TTAAGAAGTA TTATATCCAT GATCATTTTA TCCCCATTGA GAAGTACCAG 2550 TTCAGTCTTT ACCCAATATT TATGGAAGGA GTGGGAAAAC CAAAGATAAT 2600 TAATAGTTTC ACTCAAGATG ATATTGAAAA ACACCAGAGT GATGCAGGTT 2650 TATATGTAAT TGTGCCAGTA ATTATTTCCT CTTCCATCTT ATTGCTTGGA 2700 ACATTATTAA TATCACACCA AAGAATGAAA AAGCTATTTT GGGAAGATGT 2750 TCCGAACCCC AAGAATTGTT CCTGGGCACA AGGACTTAAT TTTCAGAAGA 2800 TGTTCCGAAC CCCAAGAATT GTTCCTGGGC ACAAGGACTT AATTTTCAGA 2850 AGATGCTTGA AGGCAGCATG TTCGTTAAGA GTCATCACCA CTCCCTAATC 2900 TCAAGTACCC AGGGACACAA ACACTGCGGA AGGCCACAGG GTCCTCTGCA 2950 TAGGAAAACC AGAGACCTTT GTTCACTTGT TTATCTGCTG ACCCTCCCTC 3000 CACTATTGTC CTATGACCCT GCCAAATCCC CCTCTGTGAG AAACACCCAA 3050 GAATGATCAA TAAAAAAAAA AAAAAAAAAA AAAAAAGTCG ACTCGAGAAT 3100 TC 3102 (2) INFORMATION FOR SEQ ID NO:7 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 783 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: : Met Met Cys Gin Lys Phe Tyr Val Val Leu Leu His Trp Glu Phe 1 5 10 15 Leu Tyr Val He Ala Ala Leu Asn Leu Ala Tyr Pro He Ser Pro 20 25 30 Trp Lys Phe Lys Leu Phe Cys Gly Pro Pro Asn Thr Thr Asp Asp 35 40 45 Ser Phe Leu Ser Pro Ala Gly Ala Pro Asn Asn Ala Ser Ala Leu 50 55 60 Lys Gly Ala Ser Glu Ala He Val Glu Ala Lys Phe Asn Ser Ser 65 70 75 Gly He Tyr Val Pro Glu Leu Ser Lys Thr Val Phe His Cys Cys 80 85 90 Phe Gly Asn Glu Gin Gly Gin Asn Cys Ser Ala Leu Thr Asp Asn 95 100 105 Thr Glu Gly Lys Thr Leu Ala Ser Val Val Lys Ala Ser Val Phe 110 115 120 Arg Gin Leu Gly Val Asn Trp Asp He Glu Cys Trp Met Lys Gly 125 130 135 Asp Leu Thr Leu Phe He Cys His Met Glu Pro Leu Pro Lys Asn 140 145 150 Pro Phe Lys Asn Tyr Asp Ser Lys Val His Leu Leu Tyr Asp Leu 155 160 165 Pro Glu Val He Asp Asp Ser Pro Leu Pro Pro Leu Lys Asp Ser 170 175 180 Phe Gin Thr Val Gin Cys Asn Cys Ser Leu Arg Gly Cys Glu Cys 185 190 195 His Val Pro Val Pro Arg Ala Lys Leu Asn Tyr Ala Leu Leu Met 200 205 210 Tyr Leu Glu He Thr Ser Ala Gly Val Ser Phe Gin Ser Pro Leu 215 220 225 Met Ser Leu Gin Pro Met Leu Val Val Lys Pro Asp Pro Pro Leu 230 235 240 Gly Leu His Met Glu Val Thr Asp Asp Gly Asn Leu Lys He Ser 245 250 255 Trp Asp Ser Gin Thr Met Ala Pro Phe Pro Leu Gin Tyr Gin Val 260 265 270 Lys Tyr Leu Glu Asn Ser Thr He Val Arg Glu Ala Ala Glu He 275 280 285 Val Ser Ala Thr Ser Leu Leu Val Asp Ser Val Leu Pro Gly Ser 290 295 300 Ser Tyr Glu Val Gin Val Arg Ser Lys Arg Leu Asp Gly Ser Gly 305 310 315 Val Trp Ser Asp Trp Ser Ser Pro Gin Val Phe Thr Thr Gin Asp 320 325 330 Val Val Tyr Phe Pro Pro Lys He Leu Thr Ser Val Gly Ser Asn 335 340 345 Ala Ser Phe His Cys He Tyr Lys Asn Glu Asn Gin He Val Ser 350 355 360 Ser Lys Gin He Val Trp Trp Arg Asn Leu Ala Glu Lys He Pro 365 370 375 Glu He Gin Tyr Ser He Val Ser Asp Arg Val Ser Lys Val Thr 380 385 390 Phe Ser Asn Leu Lys Ala Thr Arg Pro Arg Gly Lys Phe Thr Tyr 395 400 405 Asp Ala Val Tyr Cys Cys Asn Glu Gin Ala Cys His His Arg Tyr 410 415 420 Ala Glu Leu Tyr Val He Asp Val Asn He Asn He Ser Cys Glu 425 430 435 Thr Asp Gly Tyr Leu Thr Lys Met Thr Cys Arg Trp Ser Pro Ser 440 445 450 Thr He Gin Ser Leu Val Gly Ser Thr Val Gin Leu Arg Tyr His 455 460 465 Arg Cys Ser Leu Tyr Cys Pro Asp Ser Pro Ser He His Pro Thr 470 475 480 Ser Glu Pro Lys Thr Ala Ser Tyr Arg Glu Thr Ala Phe Met Asn 485 490 495 Val Phe Ser Ser Gin Ser Phe Tyr Tyr Leu Ala He Gin Cys Gly 500 505 510 Phe Arg He Asn His Ser Leu Gly Ser Leu Asp Ser Pro Pro Thr 515 520 525 Cys Val Leu Pro Asp Ser Val Val Lys Pro Leu Pro Pro Ser Asn 530 535 540 Val Lys Ala Glu He Thr Val Asn Thr Gly Leu Leu Lys Val Ser 545 550 555 Trp Glu Lys Pro Val Phe Pro Glu Asn Asn Leu Gin Phe Gin He 560 565 570 Arg Tyr Gly Leu Ser Gly Lys Glu He Gin Trp Lys Thr His Glu 575 580 585 Val Phe Asp Ala Lys Ser Lys Ser Ala Ser Leu Leu Val Ser Asp 590 595 600 Leu Cys Ala Val Tyr Val Val Gin Val Arg Cys Arg Arg Leu Asp 605 610 615 Gly Leu Gly Tyr Trp Ser Asn Trp Ser Ser Pro Ala Tyr Thr Leu 620 625 630 Val Met Asp Val Lys Val Pro Met Arg Gly Pro Glu Phe Trp Arg 635 640 645 Lys Met Asp Gly Asp Val Thr Lys Lys Glu Arg Asn Val Thr Leu 650 655 660 Leu Trp Lys Pro Leu Thr Lys Asn Asp Ser Leu Cys Ser Val Arg 665 670 675 Arg Tyr Val Val Lys His Arg Thr Ala His Asn Gly Thr Trp Ser 680 685 690 Glu Asp Val Gly Asn Arg Thr Asn Leu Thr Phe Leu Trp Thr Glu 695 700 705 Pro Ala His Thr Val Thr Val Leu Ala Val Asn Ser Leu Gly Ala 710 715 720 Ser Leu Val Asn Phe Asn Leu Thr Phe Ser Trp Pro Met Ser Lys 725 730 735 Val Ser Ala Val Glu Ser Leu Ser Ala Tyr Pro Leu Ser Ser Ser 740 745 750 Cys Val He Leu Ser Trp Thr Leu Ser Pro Asp Asp Tyr Ser Leu 755 760 765 Leu Tyr Leu Val He Glu Trp Lys He Leu Asn Glu Asp Asp Gly 770 775 780 Met Lys Trp 783 (2) INFORMATION FOR SEQ ID NO:8: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 2868 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8: GGGCCCCCCC TCGAAGTCGA CGGTATCGAT AAGCTTGATA TCGAATTCCG 50 GCCGGGACAC AGGTGGGACA CTCTTTTAGT CCTCAATCCC TGGCGCGAGG 100 CCACCCAAGG CAACGCAGGA CGCAGGGCGT TTGGGGACCA GGCAGCAGAC 150 TGGGGCGGTA CCTGCGGAGA GCCACGCAAC TTCTCCAGGC CTCTGACTAC 200 TTTGGAAACT GCCCGGGGCT GCGACATCAA CCCCTTAAGT CCCGGAGGCG 250 GAAAGAGGGT GGGTTGGTTT GAAAGACACA AGGAAGAAAA ATGTGCTGTG 300 GGGCGGGTTA AGTTTCCCAC CCTCTTCCCC CTTCCCGAGC AAATTAGAAA 350 CAAAACAAAT AGAAAAGCCA GCCCTCCGGC CAACCAAAGC CCCAAGCGGA 400 GCCCCAAGCG GAGCCCCAGC CGGAGCACTC CTTTAAAAGG ATTTGCAGCG 450 GTGAGGAAAA AACCAGACCC GACCGAGGAA TCGTTCTGCA AATCCAGGTG 500 TACACCTCTG AAGAAAGATG ATGTGTCAGA AATTCTATGT GGTTTTGTTA 550 CACTGGGAAT TTCTTTATGT GATAGCTGCA CTTAACCTGG CATATCCAAT 600 CTCTCCCTGG AAATTTAAGT TGTTTTGTGG ACCACCGAAC ACAACCGATG 650 ACTCCTTTCT CTCACCTGCT GGAGCCCCAA ACAATGCCTC GGCTTTGAAG 700 GGGGCTTCTG AAGCAATTGT TGAAGCTAAA TTTAATTCAA GTGGTATCTA 750 CGTTCCTGAG TTATCCAAAA CAGTCTTCCA CTGTTGCTTT GGGAATGAGC 800 AAGGTCAAAA CTGCTCTGCA CTCACAGACA ACACTGAAGG GAAGACACTG 850 GCTTCAGTAG TGAAGGCTTC AGTTTTTCGC CAGCTAGGTG TAAACTGGGA 900 CATAGAGTGC TGGATGAAAG GGGACTTGAC ATTATTCATC TGTCATATGG 950 AGCCATTACC TAAGAACCCC TTCAAGAATT ATGACTCTAA GGTCCATCTT 1000 TTATATGATC TGCCTGAAGT CATAGATGAT TCGCCTCTGC CCCCACTGAA 1050 AGACAGCTTT CAGACTGTCC AATGCAACTG CAGTCTTCGG GGATGTGAAT 1100 GTCATGTGCC AGTACCCAGA GCCAAACTCA ACTACGCTCT TCTGATGTAT 1150 TTGGAAATCA CATCTGCCGG TGTGAGTTTT CAGTCACCTC TGATGTCACT 1200 GCAGCCCATG CTTGTTGTGA AACCCGATCC ACCCTTAGGT TTGCATATGG 1250 AAGTCACAGA TGATGGTAAT TTAAAGATTT CTTGGGACAG CCAAACAATG 1300 GCACCATTTC CGCTTCAATA TCAGGTGAAA TATTTAGAGA ATTCTACAAT 1350 TGTAAGAGAG GCTGCTGAAA TTGTCTCAGC TACATCTCTG CTGGTAGACA 1400 GTGTGCTTCC TGGATCTTCA TATGAGGTCC AGGTGAGGAG CAAGAGACTG 1450 GATGGTTCAG GAGTCTGGAG TGACTGGAGT TCACCTCAAG TCTTTACCAC 1500 ACAAGATGTT GTGTATTTTC CACCCAAAAT TCTGACTAGT GTTGGATCGA 1550 ATGCTTCCTT TCATTGCATC TACAAAAACG AAAACCAGAT TGTCTCCTCA 1600 AAACAGATAG TTTGGTGGAG GAATCTAGCT GAGAAAATCC CTGAGATACA 1650 GTACAGCATT GTGAGTGACC GAGTTAGCAA AGTTACCTTC TCCAACCTGA 1700 AAGCCACCAG ACCTCGAGGG AAGTTTACCT ATGACGCAGT GTACTGCTGC 1750 AATGAGCAGG CGTGCCATCA CCGCTATGCT GAATTATACG TGATCGATGT 1800 CAATATCAAT ATATCATGTG AAACTGACGG GTACTTAACT AAAATGACTT 1850 GCAGATGGTC ACCCAGCACA ATCCAATCAC TAGTGGGAAG CACTGTGCAG 1900 CTGAGGTATC ACAGGTGCAG CCTGTATTGT CCTGATAGTC CATCTATTCA 1950 TCCTACGTCT GAGCCCAAAA CTGCGTCTTA CAGAGAGACG GCTTTTATGA 2000 ATGTGTTTTC CAGCCAATCT TTCTATTATC TGGCTATACA ATGTGGATTC 2050 AGGATCAACC ATTCTTTAGG TTCACTTGAC TCGCCACCAA CGTGTGTCCT 2100 TCCTGACTCC GTAGTAAAAC CACTACCTCC ATCTAACGTA AAAGCAGAGA 2150 TTACTGTAAA CACTGGATTA TTGAAAGTAT CTTGGGAAAA GCCAGTCTTT 2200 CCGGAGAATA ACCTTCAATT CCAGATTCGA TATGGCTTAA GTGGAAAAGA 2250 AATACAATGG AAGACACATG AGGTATTCGA TGCAAAGTCA AAGTCTGCCA 2300 GCCTGCTGGT GTCAGACCTC TGTGCAGTCT ATGTGGTCCA GGTTCGCTGC 2350 CGGCGGTTGG ATGGACTAGG ATATTGGAGT AATTGGAGCA GTCCAGCCTA 2400 TACGCTTGTC ATGGATGTAA AAGTTCCTAT GAGAGGGCCT GAATTTTGGA 2450 GAAAAATGGA TGGGGACGTT ACTAAAAAGG AGAGAAATGT CACCTTGCTT 2500 TGGAAGCCCC TGACGAAAAA TGACTCACTG TGTAGTGTGA GGAGGTACGT 2550 GGTGAAGCAT CGTACTGCCC ACAATGGGAC GTGGTCAGAA GATGTGGGAA 2600 ATCGGACCAA TCTCACTTTC CTGTGGACAG AACCAGCGCA CACTGTTACA 2650 GTTCTGGCTG TCAATTCCCT CGGCGCTTCC CTTGTGAATT TTAACCTTAC 2700 CTTCTCATGG CCCATGAGTA AAGTGAGTGC TGTGGAGTCA CTCAGTGCTT 2750 ATCCCCTGAG CAGCAGCTGT GTCATCCTTT CCTGGACACT GTCACCTGAT 2800 GATTATAGTC TGTTATATCT GGTTATTGAA TGGAAGATCC TTAATGAAGA 2850 TGATGGAATG AAGTGGCT 2868 (2) INFORMATION FOR SEQ ID NO:9: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 9: GGGTTAAGTT TCCCACCC 18 (2) INFORMATION FOR SEQ ID NO:10: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:10: GGGTGGGAAA CTTAACCC 18 (2) INFORMATION FOR SEQ ID NO:11: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 11: AGGATACAGT GGGATCCC 18 (2) INFORMATION FOR SEQ ID NO:12: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:12: GCCCGAGCAC TCCTTTAA 18 (2) INFORMATION FOR SEQ ID NO:13: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:13: TTAAAGGAGT GCTCCCGC 18 (2) INFORMATION FOR SEQ ID NO: 14: (i) SEQUENCE CHARACTERISTICS : (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:14: GAGCGGCCCT GTTAGATA 18 (2) INFORMATION FOR SEQ ID NO: 15: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:15: GTATACACCT CTGAAGAA 18 (2) INFORMATION FOR SEQ ID NO:16: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:16: TTCTTCAGAG GTGTACAC 18 (2) INFORMATION FOR SEQ ID NO:17: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:17: ATGCGAGGCT ACTTCTAT 18 (2) INFORMATION FOR SEQ ID NO:18: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:18: CTCTCCCTGG AAATTTAA 18 (2) INFORMATION FOR SEQ ID NO:19: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:19: TTAAATTTCC AGGGAGAG 18 (2) INFORMATION FOR SEQ ID NO:20: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:20: ATTTGAAGGA GTTAAGCC 18 (2) INFORMATION FOR SEQ ID NO:21: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:21: AATTTAATTC AAGTGGTA 18 (2) INFORMATION FOR SEQ ID NO:22: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:22: TACCAGTTGA ATTAAATT 18 (2) INFORMATION FOR SEQ ID NO:23: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:23: GTATCACTTC ATAATATA 18 (2) INFORMATION FOR SEQ ID NO:24: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:24: GATGGTCAGG GTGAACTG 18 (2) INFORMATION FOR SEQ ID NO:25: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:25: CAGTTCACCC TGACCATC 18 (2) INFORMATION FOR SEQ ID NO:26: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:26: GAGGCGAATG TGCGGATT IB (2) INFORMATION FOR SEQ ID NO:27: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear ( i) SEQUENCE DESCRIPTION: SEQ ID NO:27: CTTAAATCTC CAAGGAGT 18 (2) INFORMATION FOR SEQ ID NO:28: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:28: ACTCCTTGGA GATTTAAG 18 (2) INFORMATION FOR SEQ ID NO:29: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:29: AAGTCTTAAG CCAGACTT 18 (2) INFORMATION FOR SEQ ID NO:30: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:30: TCTAAGGCAC ATCCCAGC 18 (2) INFORMATION FOR SEQ ID NO:31: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:31: GCTGGGATGT GCCTTAGA 18 (2) INFORMATION FOR SEQ ID NO: 32: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:32: CGCAATGAAT TGACCCCC 18 (2) INFORMATION FOR SEQ ID NO:33: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:33: TACTTCAGAG AAGTACAC 18 (2) INFORMATION FOR SEQ ID NO:34: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear ( i) SEQUENCE DESCRIPTION: SEQ ID NO:34: GTGTACTTCT CTGAAGTA 18 (2) INFORMATION FOR SEQ ID NO:35: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:35: GAATCACGGT AACTATCA 18 (2) INFORMATION FOR SEQ ID NO: 36: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 36: CAGCTGTCTC ATAATGTC 18 (2) INFORMATION FOR SEQ ID NO:37: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:37: GACATTATGA GACAGCTG 18 (2) INFORMATION FOR SEQ ID NO:38: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:38: TTCGTCAAGC CATCTGAT 18 (2) INFORMATION FOR SEQ ID NO:39: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 8 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:39: His Gin Asn Leu Ser Asp Gly Lys 1 5 8 (2) INFORMATION FOR SEQ ID NO:40: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 8 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:40: His Gin Asn He Ser Asp Gly Lys 1 5 8 (2) INFORMATION FOR SEQ ID NO:41: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 7 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:41: His Gin Ser Leu Gly Thr Gin 1 5 7 (2) INFORMATION FOR SEQ ID NO: 2: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 8 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:42: Val He Ser Ser His Leu Gly Gin 1 5 8 (2) INFORMATION FOR SEQ ID NO:43: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 11 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:43: Pro Lys Asn Ser Ser Met He Ser Asn Thr Pro 1 5 10 11 (2) INFORMATION FOR SEQ ID NO:44: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID N0:44: Asp Lys Thr His Thr Cys Pro Pro Cys Pro 1 5 10 (2) INFORMATION FOR SEQ ID NO:45: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 51 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:45: GTCAGTCTCC CAGTTCCAGA CTTGTGTGCA GTCTATGCTG TTCAGGTGCG 50 C 51 (2) INFORMATION FOR SEQ ID NO:46: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 7127 base pairs (B) TYPE: Nucleic Acid (C) STRANDEDNESS: Double (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:46: TTCGAGCTCG CCCGACATTG ATTATTGACT AGTTATTAAT AGTAATCAAT 50 TACGGGGTCA TTAGTTCATA GCCCATATAT GGAGTTCCGC GTTACATAAC 100 TTACGGTAAA TGGCCCGCCT GGCTGACCGC CCAACGACCC CCGCCCATTG 150 ACGTCAATAA TGACGTATGT TCCCATAGTA ACGCCAATAG GGACTTTCCA 200 TTGACGTCAA TGGGTGGAGT ATTTACGGTA AACTGCCCAC TTGGCAGTAC 250 ATCAAGTGTA TCATATGCCA AGTACGCCCC CTATTGACGT CAATGACGGT 300 AAATGGCCCG CCTGGCATTA TGCCCAGTAC ATGACCTTAT GGGACTTTCC 350 TACTTGGCAG TACATCTACG TATTAGTCAT CGCTATTACC ATGGTGATGC 400 GGTTTTGGCA GTACATCAAT GGGCGTGGAT AGCGGTTTGA CTCACGGGGA 450 TTTCCAAGTC TCCACCCCAT TGACGTCAAT GGGAGTTTGT TTTGGCACCA 500 AAATCAACGG GACTTTCCAA AATGTCGTAA CAACTCCGCC CCATTGACGC 550 AAATGGGCGG TAGGCGTGTA CGGTGGGAGG TCTATATAAG CAGAGCTCGT 600 TTAGTGAACC GTCAGATCGC CTGGAGACGC CATCCACGCT GTTTTGACCT 650 CCATAGAAGA CACCGGGACC GATCCAGCCT CCGCGGCCGG GAACGGTGCA 700 TTGGAACGCG GATTCCCCGT GCCAAGAGTG ACGTAAGTAC CGCCTATAGA 750 GTCTATAGGC CCACCCCCTT GGCTTCGTTA GAACGCGGCT ACAATTAATA 800 CATAACCTTA TGTATCATAC ACATACGATT TAGGTGACAC TATAGAATAA 850 CATCCACTTT GCCTTTCTCT CCACAGGTGT CCACTCCCAG GTCCAACTGC 900 ACCTCGGTTC TATCGATATG CATTGGGGAA CCCTGTGCGG ATTCTTGTGG 950 CTTTGGCCCT ATCTTTTCTA TGTCCAAGCT GTGCCCATCC AAAAAGTCCA 1000 AGATGACACC AAAACCCTCA TCAAGACAAT TGTCACCAGG ATCAATGACA 1050 TTTCACACAC GCAGTCAGTC TCCTCCAAAC AGAAAGTCAC CGGTTTGGAC 1100 TTCATTCCTG GGCTCCACCC CATCCTGACC TTATCCAAGA TGGACCAGAC 1150 ACTGGCAGTC TACCAACAGA TCCTCACCAG TATGCCTTCC AGAAACGTGA 1200 TCCAAATATC CAACGACCTG GAGAACCTCC GGGATCTTCT TCACGTGCTG 1250 GCCTTCTCTA AGAGCTGCCA CTTGCCCTGG GCCAGTGGCC TGGAGACCTT 1300 GGACAGCCTG GGGGGTGTCC TGGAAGCTTC AGGCTACTCC ACAGAGGTGG 1350 TGGCCCTGAG CAGGCTGCAG GGGTCTCTGC AGGACATGCT GTGGCAGCTG 1400 GACCTCAGCC CTGGGTGCGG GGTCACCGAC AAAACTCACA CATGCCCACC 1450 GTGCCCAGCA CCTGAACTCC TGGGGGGACC GTCAGTCTTC CTCTTCCCCC 1500 CAAAACCCAA GGACACCCTC ATGATCTCCC GGACCCCTGA GGTCACATGC 1550 GTGGTGGTGG ACGTGAGCCA CGAAGACCCT GAGGTCAAGT TCAACTGGTA 1600 CGTGGACGGC GTGGAGGTGC ATAATGCCAA GACAAAGCCG CGGGAGGAGC 1650 AGTACAACAG CACGTACCGT GTGGTCAGCG TCCTCACCGT CCTGCACCAG 1700 GACTGGCTGA ATGGCAAGGA GTACAAGTGC AAGGTCTCCA ACAAAGCCCT 1750 CCCAGCCCCC ATCGAGAAAA CCATCTCCAA AGCCAAAGGG CAGCCCCGAG 1800 AACCACAGGT GTACACCCTG CCCCCATCCC GGGAAGAGAT GACCAAGAAC 1850 CAGGTCAGCC TGACCTGCCT GGTCAAAGGC TTCTATCCCA GCGACATCGC 1900 CGTGGAGTGG GAGAGCAATG GGCAGCCGGA GAACAACTAC AAGACCACGC 1950 CTCCCGTGCT GGACTCCGAC GGCTCCTTCT TCCTCTACAG CAAGCTCACC 2000 GTGGACAAGA GCAGGTGGCA GCAGGGGAAC GTCTTCTCAT GCTCCGTGAT 2050 GCATGAGGCT CTGCACAACC ACTACACGCA GAAGAGCCTC TCCCTGTCTC 2100 CGGGTAAATG AGTGCGACGG CCCTAGAGTC GACCTGCAGA AGCTTCTAGA 2150 GTCGACCTGC AGAAGCTTGG CCGCCATGGC CCAACTTGTT TATTGCAGCT 2200 TATAATGGTT ACAAATAAAG CAATAGCATC ACAAATTTCA CAAATAAAGC 2250 ATTTTTTTCA CTGCATTCTA GTTGTGGTTT GTCCAAACTC ATCAATGTAT 2300 CTTATCATGT CTGGATCGAT CGGGAATTAA TTCGGCGCAG CACCATGGCC 2350 TGAAATAACC TCTGAAAGAG GAACTTGGTT AGGTACCTTC TGAGGCGGAA 2400 AGAACCAGCT GTGGAATGTG TGTCAGTTAG GGTGTGGAAA GTCCCCAGGC 2450 TCCCCAGCAG GCAGAAGTAT GCAAAGCATG CATCTCAATT AGTCAGCAAC 2500 CAGGTGTGGA AAGTCCCCAG GCTCCCCAGC AGGCAGAAGT ATGCAAAGCA 2550 TGCATCTCAA TTAGTCAGCA ACCATAGTCC CGCCCCTAAC TCCGCCCATC 2600 CCGCCCCTAA CTCCGCCCAG TTCCGCCCAT TCTCCGCCCC ATGGCTGACT 2650 AATTTTTTTT ATTTATGCAG AGGCCGAGGC CGCCTCGGCC TCTGAGCTAT 2700 TCCAGAAGTA GTGAGGAGGC TTTTTTGGAG GCCTAGGCTT TTGCAAAAAG 2750 CTGTTAATTC GAACACGCAG ATGCAGTCGG GGCGGCGCGG TCCCAGGTCC 2800 ACTTCGCATA TTAAGGTGAC GCGTGTGGCC TCGAACACCG AGCGACCCTG 2850 CAGCGACCCG CTTAACAGCG TCAACAGCGT GCCGCAGATC TGATCAAGAG 2900 ACAGGATGAG GATCGTTTCG CATGATTGAA CAAGATGGAT TGCACGCAGG 2950 TTCTCCGGCC GCTTGGGTGG AGAGGCTATT CGGCTATGAC TGGGCACAAC 3000 AGACAATCGG CTGCTCTGAT GCCGCCGTGT TCCGGCTGTC AGCGCAGGGG 3050 CGCCCGGTTC TTTTTGTCAA GACCGACCTG TCCGGTGCCC TGAATGAACT 3100 GCAGGACGAG GCAGCGCGGC TATCGTGGCT GGCCACGACG GGCGTTCCTT 3150 GCGCAGCTGT GCTCGACGTT GTCACTGAAG CGGGAAGGGA CTGGCTGCTA 3200 TTGGGCGAAG TGCCGGGGCA GGATCTCCTG TCATCTCACC TTGCTCCTGC 3250 CGAGAAAGTA TCCATCATGG CTGATGCAAT GCGGCGGCTG CATACGCTTG 3300 ATCCGGCTAC CTGCCCATTC GACCACCAAG CGAAACATCG CATCGAGCGA 3350 GCACGTACTC GGATGGAAGC CGGTCTTGTC GATCAGGATG ATCTGGACGA 3400 AGAGCATCAG GGGCTCGCGC CAGCCGAACT GTTCGCCAGG CTCAAGGCGC 3450 GCATGCCCGA CGGCGAGGAT CTCGTCGTGA CCCATGGCGA TGCCTGCTTG 3500 CCGAATATCA TGGTGGAAAA TGGCCGCTTT TCTGGATTCA TCGACTGTGG 3550 CCGGCTGGGT GTGGCGGACC GCTATCAGGA CATAGCGTTG GCTACCCGTG 3600 ATATTGCTGA AGAGCTTGGC GGCGAATGGG CTGACCGCTT CCTCGTGCTT 3650 TACGGTATCG CCGCTCCCGA TTCGCAGCGC ATCGCCTTCT ATCGCCTTCT 3700 TGACGAGTTC TTCTGAGCGG GACTCTGGGG TTCGAAATGA CCGACCAAGC 3750 GACGCCCAAC CTGCCATCAC GAGATTTCGA TTCCACCGCC GCCTTCTATG 3800 AAAGGTTGGG CTTCGGAATC GTTTTCCGGG ACGCCGGCTG GATGATCCTC 3850 CAGCGCGGGG ATCTCATGCT GGAGTTCTTC GCCCACCCCG GGAGATGGGG 3900 GAGGCTAACT GAAACACGGA AGGAGACAAT ACCGGAAGGA ACCCGCGCTA 3950 TGACGGCAAT AAAAAGACAG AATAAAACGC ACGGGTGTTG GGTCGTTTGT 4000 TCATAAACGC GGGGTTCGGT CCCAGGGCTG GCACTCTGTC GATACCCCAC 4050 CGAGACCCCA TTGGGGCCAA TACGCCCGCG TTTCTTCCTT TTCCCCACCC 4100 CAACCCCCAA GTTCGGGTGA AGGCCCAGGG CTCGCAGCCA ACGTCGGGGC 4150 GGCAAGCCCG CCATAGCCAC GGGCCCCGTG GGTTAGGGAC GGGGTCCCCC 4200 ATGGGGAATG GTTTATGGTT CGTGGGGGTT ATTCTTTTGG GCGTTGCGTG 4250 GGGTCAGGTC CACGACTGGA CTGAGCAGAC AGACCCATGG TTTTTGGATG 4300 GCCTGGGCAT GGACCGCATG TACTGGCGCG ACACGAACAC CGGGCGTCTG 4350 TGGCTGCCAA ACACCCCCGA CCCCCAAAAA CCACCGCGCG GATTTCTGGC 4400 GCCGCCGGAC GAACTAAACC TGACTACGGC ATCTCTGCCC CTTCTTCGCT 4450 GGTACGAGGA GCGCTTTTGT TTTGTATTGG TCACCACGGC CGAGTTTCCG 4500 CGGGACCCCG GCCAGGGCAC CTGTCCTACG AGTTGCATGA TAAAGAAGAC 4550 AGTCATAAGT GCGGCGACGA TAGTCATGCC CCGCGCCCAC CGGAAGGAGC 4600 TGACTGGGTT GAAGGCTCTC AAGGGCATCG GTCGAGCGGC CGCATCAAAG 4650 CAACCATAGT ACGCGCCCTG TAGCGGCGCA TTAAGCGCGG CGGGTGTGGT 4700 GGTTACGCGC AGCGTGACCG CTACACTTGC CAGCGCCCTA GCGCCCGCTC 4750 CTTTCGCTTT CTTCCCTTCC TTTCTCGCCA CGTTCGCCGG CTTTCCCCGT 4800 CAAGCTCTAA ATCGGGGGCT CCCTTTAGGG TTCCGATTTA GTGCTTTACG 4850 GCACCTCGAC CCCAAAAAAC TTGATTTGGG TGATGGTTCA CGTAGTGGGC 4900 CATCGCCCTG ATAGACGGTT TTTCGCCCTT TGACGTTGGA GTCCACGTTC 4950 TTTAATAGTG GACTCTTGTT CCAAACTGGA ACAACACTCA ACCCTATCTC 5000 GGGCTATTCT TTTGATTTAT AAGGGATTTT GCCGATTTCG GCCTATTGGT 5050 TAAAAAATGA GCTGATTTAA CAAAAATTTA ACGCGAATTT TAACAAAATA 5100 TTAACGTTTA CAATTTTATG GTGCAGGCCT CGTGATACGC CTATTTTTAT 5150 AGGTTAATGT CATGATAATA ATGGTTTCTT AGACGTCAGG TGGCACTTTT 5200 CGGGGAAATG TGCGCGGAAC CCCTATTTGT TTATTTTTCT AAATACATTC 5250 AAATATGTAT CCGCTCATGA GACAATAACC CTGATAAATG CTTCAATAAT 5300 ATTGAAAAAG GAAGAGTATG AGTATTCAAC ATTTCCGTGT CGCCCTTATT 5350 CCCTTTTTTG CGGCATTTTG CCTTCCTGTT TTTGCTCACC CAGAAACGCT 5400 GGTGAAAGTA AAAGATGCTG AAGATCAGTT GGGTGCACGA GTGGGTTACA 5450 TCGAACTGGA TCTCAACAGC GGTAAGATCC TTGAGAGTTT TCGCCCCGAA 5500 GAACGTTTTC CAATGATGAG CACTTTTAAA GTTCTGCTAT GTGGCGCGGT 5550 ATTATCCCGT GATGACGCCG GGCAAGAGCA ACTCGGTCGC CGCATACACT 5600 ATTCTCAGAA TGACTTGGTT GAGTACTCAC CAGTCACAGA AAAGCATCTT 5650 ACGGATGGCA TGACAGTAAG AGAATTATGC AGTGCTGCCA TAACCATGAG 5700 TGATAACACT GCGGCCAACT TACTTCTGAC AACGATCGGA GGACCGAAGG 5750 AGCTAACCGC TTTTTTGCAC AACATGGGGG ATCATGTAAC TCGCCTTGAT 5800 CGTTGGGAAC CGGAGCTGAA TGAAGCCATA CCAAACGACG AGCGTGACAC 5850 CACGATGCCA GCAGCAATGG CAACAACGTT GCGCAAACTA TTAACTGGCG 5900 AACTACTTAC TCTAGCTTCC CGGCAACAAT TAATAGACTG GATGGAGGCG 5950 GATAAAGTTG CAGGACCACT TCTGCGCTCG GCCCTTCCGG CTGGCTGGTT 6000 TATTGCTGAT AAATCTGGAG CCGGTGAGCG TGGGTCTCGC GGTATCATTG 6050 CAGCACTGGG GCCAGATGGT AAGCCCTCCC GTATCGTAGT TATCTACACG 6100 ACGGGGAGTC AGGCAACTAT GGATGAACGA AATAGACAGA TCGCTGAGAT 6150 AGGTGCCTCA CTGATTAAGC ATTGGTAACT GTCAGACCAA GTTTACTCAT 6200 ATATACTTTA GATTGATTTA AAACTTCATT TTTAATTTAA AAGGATCTAG 6250 GTGAAGATCC TTTTTGATAA TCTCATGACC AAAATCCCTT AACGTGAGTT 6300 TTCGTTCCAC TGAGCGTCAG ACCCCGTAGA AAAGATCAAA GGATCTTCTT 6350 GAGATCCTTT TTTTCTGCGC GTAATCTGCT GCTTGCAAAC AAAAAAACCA 6400 CCGCTACCAG CGGTGGTTTG TTTGCCGGAT CAAGAGCTAC CAACTCTTTT 6450 TCCGAAGGTA ACTGGCTTCA GCAGAGCGCA GATACCAAAT ACTGTCCTTC 6500 TAGTGTAGCC GTAGTTAGGC CACCACTTCA AGAACTCTGT AGCACCGCCT 6550 ACATACCTCG CTCTGCTAAT CCTGTTACCA GTGGCTGCTG CCAGTGGCGA 6600 TAAGTCGTGT CTTACCGGGT TGGACTCAAG ACGATAGTTA CCGGATAAGG 6650 CGCAGCGGTC GGGCTGAACG GGGGGTTCGT GCACACAGCC CAGCTTGGAG 6700 CGAACGACCT ACACCGAACT GAGATACCTA CAGCGTGAGC ATTGAGAAAG 6750 CGCCACGCTT CCCGAAGGGA GAAAGGCGGA CAGGTATCCG GTAAGCGGCA 6800 GGGTCGGAAC AGGAGAGCGC ACGAGGGAGC TTCCAGGGGG AAACGCCTGG 6850 TATCTTTATA GTCCTGTCGG GTTTCGCCAC CTCTGACTTG AGCGTCGATT 6900 TTTGTGATGC TCGTCAGGGG GGCGGAGCCT ATGGAAAAAC GCCAGCTGGC 6950 ACGACAGGTT TCCCGACTGG AAAGCGGGCA GTGAGCGCAA CGCAATTAAT 7000 GTGAGTTACC TCACTCATTA GGCACCCCAG GCTTTACACT TTATGCTTCC 7050 GGCTCGTATG TTGTGTGGAA TTGTGAGCGG ATAACAATTT CACACAGGAA 7100 ACAGCTATGA CCATGATTAC GAATTAA 7127 (2) INFORMATION FOR SEQ ID NO:47: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 397 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:47: Met His Trp Gly Thr Leu Cys Gly Phe Leu Trp Leu Trp Pro Tyr 1 5 10 15 Leu Phe Tyr Val Gin Ala Val Pro He Gin Lys Val Gin Asp Asp 20 25 30 Thr Lys Thr Leu He Lys Thr He Val Thr Arg He Asn Asp He 35 40 45 Ser His Thr Gin Ser Val Ser Ser Lys Gin Lys Val Thr Gly Leu 50 55 60 Asp Phe He Pro Gly Leu His Pro He Leu Thr Leu Ser Lys Met 65 70 75 Asp Gin Thr Leu Ala Val Tyr Gin Gin He Leu Thr Ser Met Pro 80 85 90 Ser Arg Asn Val He Gin He Ser Asn Asp Leu Glu Asn Leu Arg 95 100 105 Asp Leu Leu His Val Leu Ala Phe Ser Lys Ser Cys His Leu Pro 110 115 120 Trp Ala Ser Gly Leu Glu Thr Leu Asp Ser Leu Gly Gly Val Leu 125 130 135 Glu Ala Ser Gly Tyr Ser Thr Glu Val Val Ala Leu Ser Arg Leu 140 145 150 Gin Gly Ser Leu Gin Asp Met Leu Trp Gin Leu Asp Leu Ser Pro 155 160 165 Gly Cys Gly Val Thr Asp Lys Thr His Thr Cys Pro Pro Cys Pro 170 175 180 Ala Pro Glu Leu Leu Gly Gly Pro Ser Val Phe Leu Phe Pro Pro 185 190 195 Lys Pro Lys Asp Thr Leu Met He Ser Arg Thr Pro Glu Val Thr 200 205 210 Cys Val Val Val Asp Val Ser His Glu Asp Pro Glu Val Lys Phe 215 220 225 Asn Trp Tyr Val Asp Gly Val Glu Val His Asn Ala Lys Thr Lys 230 235 240 Pro Arg Glu Glu Gin Tyr Asn Ser Thr Tyr Arg Val Val Ser Val 245 250 255 Leu Thr Val Leu His Gin Asp Trp Leu Asn Gly Lys Glu Tyr Lys 260 265 270 Cys Lys Val Ser Asn Lys Ala Leu Pro Ala Pro He Glu Lys Thr 275 280 285 He Ser Lys Ala Lys Gly Gin Pro Arg Glu Pro Gin Val Tyr Thr 290 295 300 Leu Pro Pro Ser Arg Glu Glu Met Thr Lys Asn Gin Val Ser Leu 305 310 315 Thr Cys Leu Val Lys Gly Phe Tyr Pro Ser Asp He Ala Val Glu 320 325 330 Trp Glu Ser Asn Gly Gin Pro Glu Asn Asn Tyr Lys Thr Thr Pro 335 340 345 Pro Val Leu Asp Ser Asp Gly Ser Phe Phe Leu Tyr Ser Lys Leu 350 355 360 Thr Val Asp Lys Ser Arg Trp Gin Gin Gly Asn Val Phe Ser Cys 365 370 375 Ser Val Met His Glu Ala Leu His Asn His Tyr Thr Gin Lys Ser 380 385 390 Leu Ser Leu Ser Pro Gly Lys 395 397 (2) INFORMATION FOR SEQ ID NO:48: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 249 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:48: Glu Val Gin Leu Val Gin Ser Gly Ala Glu Val Lys Lys Pro Gly 1 5 10 15 Ala Ser Val Lys Val Ser Cys Lys Ala Ser Gly Tyr Thr Phe Thr 20 25 30 Gly Tyr Tyr Met Tyr Trp Val Arg Gin Ala Pro Gly Gin Gly Leu 35 40 45 Glu Trp Met Gly Trp He Asn Pro Asn Ser Gly Gly Thr Asn Tyr 50 55 60 Ala Gin Lys Phe Gin Gly Arg Val Thr Met Thr Arg Asp Thr Ser 65 70 75 He Gly Thr Ala Tyr Met Glu Leu Ser Arg Leu Ser Ser Asp Asp 80 85 90 Thr Ala Val Tyr Tyr Cys Ala Arg Asp Arg Tyr Tyr Gly Ser Ser 95 100 105 Ala Tyr His Arg Gly Ser Tyr Tyr Met Asp Val Trp Gly Arg Gly 110 115 120 Thr Leu Val Thr Val Ser Ser Gly Gly Gly Gly Thr Gly Gly Gly 125 130 135 Gly Ser Gly Gly Gly Gly Ser Ser Glu Leu Thr Gin Asp Pro Ala 140 145 150 Val Ser Val Ala Leu Gly Gin Thr Val Arg He Thr Cys Gin Gly 155 160 165 Asp Ser Leu Arg Ser Tyr Tyr Ala Ser Trp Tyr Gin Gin Lys Pro 170 175 180 Gly Gin Ala Pro Val Leu Val He Tyr Gly Lys Asn Asn Arg Pro 185 190 195 Ser Gly He Pro Asp Arg Phe Ser Gly Ser Ser Ser Gly Asn Thr 200 205 210 Ala Ser Leu Thr He Thr Gly Ala Gin Ala Glu Asp Glu Ala Asp 215 220 225 Tyr Tyr Cys Asn Ser Arg Asp Ser Ser Gly Asn His Val Val Phe 230 235 240 Gly Gly Gly Thr Lys Leu Thr Val Leu 245 249 (2) INFORMATION FOR SEQ ID NO:49: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 250 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:49: Glu Val Gin Leu Val Gin Ser Gly Ala Glu Val Lys Lys Pro Gly 1 5 10 15 Glu Ser Leu Lys He Ser Cys Gin Gly Ser Gly Phe Thr Phe Ser 20 25 30 Ser Tyr Lys Met Asn Trp Val Arg Gin Ala Pro Gly Lys Gly Leu 35 40 45 Glu Trp Met Gly Gly He He Pro He Phe Gly Thr Ala Asn Tyr 50 55 60 Ala Gin Lys Phe Gin Gly Arg Val Thr He Thr Ala Asp Glu Ser 65 70 75 Thr Ser Thr Ala Tyr Met Glu Leu Ser Ser Leu Arg Ser Glu Asp 80 85 90 Thr Ala Val Tyr Tyr Cys Ala Arg Asp Arg Val Val Val Pro Ala 95 100 105 Thr Ser Leu Arg Gly Gly Met Asp Val Trp Gly Gin Gly Thr Thr 110 115 120 Val Thr Val Ser Ser Gly Gly Gly Gly Ser Gly Gly Gly Gly Ser 125 130 135 Gly Gly Gly Gly Ser Gin Ser Val Leu Thr Gin Pro Ala Ser Val 140 145 150 Ser Gly Ser Pro Gly Gin Ser He Thr He Ser Cys Thr Gly Thr 155 160 165 Ser Ser Asp Val Gly Gly Tyr Asn Tyr Val Ser Trp Tyr Gin Gin 170 175 180 His Pro Gly Lys Ala Pro Lys Leu Met He Tyr Glu Gly Ser Lys 185 190 195 Arg Pro Ser Gly Val Ser Asn Arg Phe Ser Gly Ser Lys Ser Gly 200 205 210 Ser Thr Ala Ser Leu Thr He Ser Gly Leu Gin Ala Glu Asp Glu 215 220 225 Ala Asp Tyr Tyr Cys Ser Ser Tyr Thr Thr Arg Ser Thr Arg Val 230 235 240 Phe Gly Gly Gly Thr Lys Leu Thr Val Leu 245 250 (2) INFORMATION FOR SEQ ID NO:50: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 241 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO:50: Gin Val Arg Leu Gin Gin Ser Gly Gly Gly Leu Val Gin Pro Gly 1 5 10 15 Arg Ser Leu Arg Leu Ser Cys Ala Ala Ser Gly Phe Thr Phe Asp 20 25 30 Asp Tyr Ala Met His Trp Val Arg Gin Ala Pro Gly Lys Gly Leu 35 40 45 Glu Trp Val Ser Gly Met Thr Trp Asn Ser Gly Ser He Gly Tyr 50 55 60 Ala Asp Ser Val Lys Gly Arg Phe Thr He Ser Arg Asp Asn Ala 65 70 75 Lys Asn Ser Leu Tyr Leu Gin Met Asn Ser Leu Arg Ala Glu Asp 80 85 90 Thr Ala Val Tyr Tyr Cys Ala Arg Glu Pro His Asn Thr Asp Ala 95 100 105 Phe Asp He Trp Gly Arg Gly Thr Leu Val Thr Val Ser Ser Gly 110 115 120 Gly Gly Gly Pro Gly Gly Gly Gly Ser Gly Gly Gly Gly Ser Asp 125 130 135 Val Val Met Thr Gin Ser Pro Ser Phe Leu Ser Ala Phe Val Gly 140 145 150 Asp Thr He Thr He Thr Cys Arg Ala Ser Gin Gly He Tyr Asn 155 160 165 Tyr Leu Ala Trp Tyr Gin Gin Lys Pro Gly Lys Ala Pro Lys Leu 170 175 180 Leu He Tyr Ala Ala Ser Thr Leu Gin Ser Gly Val Pro Ser Arg 185 190 195 Phe Ser Gly Ser Gly Ser Gly Thr Glu Phe Thr Leu Thr He Ser 200 205 210 Ser Leu Gin Pro Glu Asp Phe Gly Thr Tyr Tyr Cys Gin Gin Leu 215 220 225 He Ser Tyr Pro Leu Thr Phe Gly Gly Gly Thr Lys Val Glu He 230 235 240 Lys 241 (2) INFORMATION FOR SEQ ID NO:51: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 894 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: Linear (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 51: Met Met Cys Gin Lys Phe Tyr Val Val Leu Leu His Trp Glu Phe 1 5 10 15 Leu Tyr Val He Ala Ala Leu Asn Leu Ala Tyr Pro He Ser Pro 20 25 30 Trp Lys Phe Lys Leu Phe Cys Gly Pro Pro Asn Thr Thr Asp Asp 35 40 45 Ser Phe Leu Ser Pro Ala Gly Ala Pro Asn Asn Ala Ser Ala Leu 50 55 60 Lys Gly Ala Ser Glu Ala He Val Glu Ala Lys Phe Asn Ser Ser 65 70 75 Gly He Tyr Val Pro Glu Leu Ser Lys Thr Val Phe His Cys Cys 80 85 90 Phe Gly Asn Glu Gin Gly Gin Asn Cys Ser Ala Leu Thr Asp Asn 95 100 105 Thr Glu Gly Lys Thr Leu Ala Ser Val Val Lys Ala Ser Val Phe 110 115 120 Arg Gin Leu Gly Val Asn Trp Asp He Glu Cys Trp Met Lys Gly 125 130 135 Asp Leu Thr Leu Phe He Cys His Met Glu Pro Leu Pro Lys Asn 140 145 150 Pro Phe Lys Asn Tyr Asp Ser Lys Val His Leu Leu Tyr Asp Leu 155 160 165 Pro Glu Val He Asp Asp Ser Pro Leu Pro Pro Leu Lys Asp Ser 170 175 180 Phe Gin Thr Val Gin Cys Asn Cys Ser Leu Arg Gly Cys Glu Cys 185 190 195 His Val Pro Val Pro Arg Ala Lys Leu Asn Tyr Ala Leu Leu Met 200 205 210 Tyr Leu Glu He Thr Ser Ala Gly Val Ser Phe Gin Ser Pro Leu 215 220 225 Met Ser Leu Gin Pro Met Leu Val Val Lys Pro Asp Pro Pro Leu 230 235 240 Gly Leu His Met Glu Val Thr Asp Asp Gly Asn Leu Lys He Ser 245 250 255 Trp Asp Ser Gin Thr Met Ala Pro Phe Pro Leu Gin Tyr Gin Val 260 265 270 Lys Tyr Leu Glu Asn Ser Thr He Val Arg Glu Ala Ala Glu He 275 280 285 Val Ser Ala Thr Ser Leu Leu Val Asp Ser Val Leu Pro Gly Ser 290 295 300 Ser Tyr Glu Val Gin Val Arg Ser Lys Arg Leu Asp Gly Ser Gly 305 310 315 Val Trp Ser Asp Trp Ser Ser Pro Gin Val Phe Thr Thr Gin Asp 320 325 330 Val Val Tyr Phe Pro Pro Lys He Leu Thr Ser Val Gly Ser Asn 335 340 345 Ala Ser Phe His Cys He Tyr Lys Asn Glu Asn Gin He He Ser 350 355 360 Ser Lys Gin He Val Trp Trp Arg Asn Leu Ala Glu Lys He Pro 365 370 375 Glu He Gin Tyr Ser He Val Ser Asp Arg Val Ser Lys Val Thr 380 385 390 Phe Ser Asn Leu Lys Ala Thr Arg Pro Arg Gly Lys Phe Thr Tyr 395 400 405 Asp Ala Val Tyr Cys Cys Asn Glu Gin Ala Cys His His Arg Tyr 410 415 420 Ala Glu Leu Tyr Val He Asp Val Asn He Asn He Ser Cys Glu 425 430 435 Thr Asp Gly Tyr Leu Thr Lys Met Thr Cys Arg Trp Ser Pro Ser 440 445 450 Thr He Gin Ser Leu Val Gly Ser Thr Val Gin Leu Arg Tyr His 455 460 465 Arg Arg Ser Leu Tyr Cys Pro Asp Ser Pro Ser He His Pro Thr 470 475 480 Ser Glu Pro Lys Asn Cys Val Leu Gin Arg Asp Gly Phe Tyr Glu 485 490 495 Cys Val Phe Gin Pro He Phe Leu Leu Ser Gly Tyr Thr Met Trp 500 505 510 He Arg He Asn His Ser Leu Gly Ser Leu Asp Ser Pro Pro Thr 515 520 525 Cys Val Leu Pro Asp Ser Val Val Lys Pro Leu Pro Pro Ser Asn 530 535 540 Val Lys Ala Glu He Thr Val Asn Thr Gly Leu Leu Lys Val Ser 545 550 555 Trp Glu Lys Pro Val Phe Pro Glu Asn Asn Leu Gin Phe Gin He 560 565 570 Arg Tyr Gly Leu Ser Gly Lys Glu He Gin Trp Lys Thr His Glu 575 580 585 Val Phe Asp Ala Lys Ser Lys Ser Ala Ser Leu Leu Val Ser Asp 590 595 600 Leu Cys Ala Val Tyr Val Val Gin Val Arg Cys Arg Arg Leu Asp 605 610 615 Gly Leu Gly Tyr Trp Ser Asn Trp Ser Ser Pro Ala Tyr Thr Leu 620 625 630 Val Met Asp Val Lys Val Pro Met Arg Gly Pro Glu Phe Trp Arg 635 640 645 Lys Met Asp Gly Asp Val Thr Lys Lys Glu Arg Asn Val Thr Leu 650 655 660 Leu Trp Lys Pro Leu Thr Lys Asn Asp Ser Leu Cys Ser Val Arg 665 670 675 Arg Tyr Val Val Lys His Arg Thr Ala His Asn Gly Thr Trp Ser 680 685 690 Glu Asp Val Gly Asn Arg Thr Asn Leu Thr Phe Leu Trp Thr Glu 695 700 705 Pro Ala His Thr Val Thr Val Leu Ala Val Asn Ser Leu Gly Ala 710 715 720 Ser Leu Val Asn Phe Asn Leu Thr Phe Ser Trp Pro Met Ser Lys 725 730 735 Val Ser Ala Val Glu Ser Leu Ser Ala Tyr Pro Leu Ser Ser Ser 740 745 750 Cys Val He Leu Ser Trp Thr Leu Ser Pro Asp Asp Tyr Ser Leu 755 760 765 Leu Tyr Leu Val He Glu Trp Lys He Leu Asn Glu Asp Asp Gly 770 775 780 Met Lys Trp Leu Arg He Pro Ser Asn Val Lys Lys Phe Tyr He 785 790 795 His Asp Asn Phe He Pro He Glu Lys Tyr Gin Phe Ser Leu Tyr 800 805 810 Pro Val Phe Met Glu Gly Val Gly Lys Pro Lys He He Asn Gly 815 820 825 Phe Thr Lys Asp Ala He Asp Lys Gin Gin Asn Asp Ala Gly Leu 830 835 840 Tyr Val He Val Pro He He He Ser Ser Cys Val Leu Leu Leu 845 850 855 Gly Thr Leu Leu He Ser His Gin Arg Met Lys Lys Leu Phe Trp 860 865 870 Asp Asp Val Pro Asn Pro Lys Asn Cys Ser Trp Ala Gin Gly Leu 875 880 885 Asn Phe Gin Lys Arg Thr Asp Thr Leu 890 894

Claims: WHAT IS CLAIMED IS: 1. Isolated WSX receptor. 2. The WSX receptor of claim 1 comprising an amino acid sequence selected from the group consisting of: (a) the amino acid sequence of mature human WSX receptor variant 6.4 shown in Figs 2A-B: (b) the amino acid sequence of mature human WSX receptor variant 12.1 shown in Figs. 2A-B; and (c) the amino acid sequence of mature human WSX receptor variant 13.2 shown in Figs 2A-B. 3. The WSX receptor of claim 2 which is mature human WSX receptor variant 13.2. 4. The WSX receptor of claim 1 which is WSX receptor extracellular domain (ECD). 5. The WSX receptor ECD of claim 4 which is conjugated with, or fused to, a molecule which increases the serum half-life thereof. 6. The WSX receptor ECD of claim 5 which is conjugated with polyethylene glycol (PEG) 7. A composition comprising the WSX receptor ECD of claim 4 and a physiologically acceptable carrier. 8. The composition of claim 7 further comprising WSX ligand. 9. The WSX receptor of claim 1 which is chimeric WSX receptor. 10. The chimeric WSX receptor of claim 9 comprising a WSX receptor amino acid sequence fused to an immunoglobulin sequence. 1 1. The chimeric WSX receptor of claim 10 comprising a fusion ofa WSX receptor extracellular domain sequence to an immunoglobulin constant domain sequence. 12. The chimeric WSX receptor of claim 1 1 wherein said constant domain sequence is that of an immunoglobulin heavy chain. 13. A method for identifying a molecule which binds to the WSX receptor comprising exposing the WSX receptor to a molecule suspected of binding thereto and determining binding of the molecule to the WSX receptor. 14. A method for identifying a molecule which activates the WSX receptor comprising exposing the WSX receptor to a molecule suspected of being capable of activating the WSX receptor and measuring activation of the WSX receptor. 15. A me od for purifying a molecule which binds to the WSX receptor comprising adsorbing the molecule to WSX receptor immobilized on a solid phase and recovering the molecule from the immobilized WSX receptor. 16. An antibody that specifically binds to the WSX receptor of claim 1. 17. The antibody of claim 16 which is an agonist antibody. 18. The antibody of claim 17 which has an IC50 in a KIRA ELISA of about 0.5μg/ml or less. 19. The antibody of claim 16 which is a neutralizing antibody. 20. The antibody of claim 16 which is a human or humanized antibody. 21. The antibody of claim 16 which is an antibody fragment. 22. The antibody fragment of claim 21 which is an F(ab')2- 23. A composition comprising the antibody of claim 16 and a physiologically acceptable carrier. 24. The composition of claim 23 further comprising a cytokine. 25. A method for activating the WSX receptor comprising exposing the WSX receptor to an amount ofthe antibody of claim 17 which is effective for activating the WSX receptor. 26. A method for enhancing proliferation or differentiation ofa cell comprising the WSX receptor comprising exposing the cell to an amount of the antibody of claim 17 which is effective for enhancing proliferation or differentiation ofthe cell. 27. The method of claim 26 wherein the cell is a CD34+ cell. 28. A method for determining the presence ofa WSX receptor comprising exposing a test sample suspected of containing the WSX receptor to the antibody of claim 16 and determining binding of said antibody to the test sample. 29. An isolated nucleic acid molecule encoding the WSX receptor of claim 1. 30. An isolated nucleic acid molecule encoding the WSX receptor ECD of claim 4. 31. An isolated nucleic acid molecule encoding the chimeric WSX receptor of claim 9. 32. The isolated nucleic acid molecule of any one of claims 29-31 further comprising a promoter operably linked to the nucleic acid molecule. 33. An expression vector comprising the nucleic acid molecule of any one of claims 29-31 operably linked to control sequences recognized by a host cell transformed with the vector. 34. A host cell comprising the vector of claim 33. 35. A process of using a nucleic acid molecule encoding the WSX receptor to effect production ofthe WSX receptor comprising culturing the host cell of claim 34. 36. A method for enhancing proliferation or differentiation ofa cell comprising the WSX receptor comprising exposing the cell to an amount of WSX ligand which is effective for enhancing proliferation or differentiation ofthe cell. 37. The method of claim 36 wherein the WSX receptor is the WSX receptor variant 13.2. 38. The method of claim 36 wherein the cell is a hematopoietic progenitor cell. 39. The method of claim 36 wherein the WSX ligand is OB protein. 40. The method of claim 36 wherein the WSX ligand is an anti-WSX receptor agonist antibody. 41. The method of claim 36 which enhances proliferation or differentiation of lymphoid blood cell lineages. 42. The method of claim 36 which enhances proliferation or differentiation of myeloid blood cell lineages. 43. The method of claim 36 which enhances proliferation or differentiation of erythroid blood cell lineages. 44. The method of claim 36 further comprising exposing the cell to a further cytokine. 45. The method of claim 44 wherein the further cytokine is a lineage-specific cytokine. 46. The method of claim 36 wherein the cell is present in a mammal. 47. The method of claim 46 wherein the mammal is a human. 48. The method of claim 46 wherein the mammal is suffering from, or is expected to suffer from, decreased blood cell levels. 49. The method of claim 48 wherein the decreased blood cell levels are caused by chemotherapy, radiation therapy, or bone marrow transplantation therapy. 50. A method for repopulating blood cells in a mammal comprising administering to the mammal a therapeutically effective amount ofa WSX ligand. 51. The method of claim 50 wherein the blood cells are erythroid cells. 52. The method of claim 50 wherein the blood cells are myeloid cells. 53. The method of claim 50 wherein the blood cells are lymphoid cells. 54. The method of claim 50 comprising administering a further cytokine to the mammal in an amount which leads to a synergistic repopulation ofthe blood cells in the mammal. 55. A pharmaceutical composition comprising WSX ligand, a further cytokine, and a physiologically acceptable carrier. 56. An article of manufacture, comprising: a container; a label on the container; and a composition comprising an active agent contained within the container; wherein the composition is effective for repopulating blood cells in a mammal, the label on the container indicates that the composition can be used for repopulating blood cells in a mammal and the active agent in the composition is a WSX ligand. 57. The article of manufacture of claim 56 comprising a further container which holds a further cytokine. 58. An article of manufacture, comprising: a container; a label on the container; and a composition comprising an active agent contained within the container; wherein the composition is effective for decreasing body weight or fat-depot weight or decreasing food intake in an obese mammal, the label on the container indicates that die composition can be used for treating obesity in a mammal and the active agent in the composition is an agonist anti-WSX receptor antibody.

Inventors: BENNETT BRIAN, CARTER PAUL J, CHIANG NANCY Y, KIM KYUNG JIN, MATTHEWS WILLIAM, RODRIGUES MARIA L, BENNETT, BRIAN, CARTER, PAUL, J., CHIANG, NANCY, Y., KIM, KYUNG, JIN, MATTHEWS, WILLIAM, RODRIGUES, MARIA, L.
Applicants: GENENTECH INC, GENENTECH, INC.
Application year: 1997
Main classification: C12N15
IPC codes: A61K31, A61K38, A61K39, A61P1, A61P3, A61P7, A61P9, A61P13, A61P17, A61P19, A61P31, A61P35, A61P37, A61P43, C07K14, C07K16, C07K19, C12N5, C12N15, C12P21, G01N33