USE OF GROWTH DIFFERENCIATION FACTOR-9 (GDF-9) AS A CONTRACEPTIVE

Abstract: Growth differentiation factor-9 (GDF-9) is disclosed along with its polynucleotide sequence and amino acid sequence. Also disclosed is a method for inhibiting oocyte maturation using GDF-9 inhibitors or by inducing an immune response to GDF-9 polypeptide or fragments thereof.

Description: USE OF GROWTH DIFFERENTIATION FACTOR-9 (GDF-9) AS A CONTRACEPTIVE BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates generally to growth factors and specifically to a new member ofthe transforming growth factor beta (TGF-β) superfamily, which is denoted, growth differentiation factor-9 (GDF-9) and methods of use as a contraceptive. 2. Description of Related Art The transforming growth factor β (TGF-β) superfamily encompasses a group of structurally-related proteins which affect a wide range of differentiation processes during embryonic development. The family includes, Mullerian inhibiting substance (MIS), which is required for normal male sex development (Behringer, et al., Nature, 345:167. 1990), Drosophila decapentaplegic (DPP) gene product, which is required for dorsal- ventral axis formation and morphogenesis ofthe imaginal disks (Padgett, et al, Nature, 325:81-84. 1987), the Xenopus Vg-1 gene product, which localizes to the vegetal pole of eggs ((Weeks, et al, Cell, 5_l:861-867, 1987), the activins (Mason, et al, Biochem, Biophys. Res. Commun., 135:957-964. 1986), which can induce the formation of mesoderm and anterior structures in Xenopus embryos (Thomsen, et al, Cell, 63:485. 1990), and the bone moφhogenetic proteins (BMPs, osteogenin, OP- 1 ) which can induce de novo cartilage and bone formation (Sampath, et al, J. Biol Chem., 265:13198. 1990). The TGF-βs can influence a variety of differentiation processes, including adipogenesis, myogenesis, chondrogenesis, hematopoiesis, and epithelial cell differentiation (for review, see Massague, Cell 49:437, 1987). The proteins ofthe TGF-β family are initially synthesized as a large precursor protein which subsequently undergoes proteolytic cleavage at a cluster of basic residues approximately 110-140 amino acids from the C-terminus. The C-terminal regions ofthe proteins are all structurally related and the different family members can be classified into distinct subgroups based on the extent of their homology. Although the homologies within particular subgroups range from 70% to 90% amino acid sequence identity, the homologies between subgroups are significantly lower, generally ranging from only 20%) to 50%). In each case, the active species appears to be a disulfide-linked dimer of C- terminal fragments. For most of the family members that have been studied, the homodimeric species has been found to be biologically active, but for other family members, like the inhibins (Ling, et al, Nature, 321 :779, 1986) and the TGF-βs (Cheifetz, et al, Cell, 48:409, 1987), heterodimers have also been detected, and these appear to have different biological properties than the respective homodimers. The inhibins and activins were originally purified from follicular fluid and shown to have counteracting effects on the release of follicle-stimulating hormone by the pituitary gland. Although the mRNAs for all three inhibin/activin subunits ( a, βA and βB) have been detected in the ovary, none of these appear to be ovary-specific (Meunier, et al, Proc.Natl.Acad.Sci. USA, 85:247, 1988). MIS has also been shown to be expressed by granulosa cells and the effects of MIS on ovarian development have been documented both in vivo in transgenic mice expressing MIS ectopically (Behringer, supra) and in vitro in organ culture (Vigier, et al, Development, 100:43. 1987). Identification of new factors that are tissue-specific in their expression pattern will provide a greater understanding of that tissue's development and function. SUMMARY OF THE INVENTION The present invention provides a cell growth and differentiation factor, GDF-9, a polynucleotide sequence which encodes the factor and antibodies which are immunoreactive with the factor. This factor appears to relate to various cell proliferative disorders, especially those involving ovarian tumors, such as granulosa cell tumors. GDF-9 is exclusively expressed in oocytes and plays a role in maturation of oocytes. Thus, in one embodiment, the invention provides a method for detecting a cell proliferative disorder of ovarian origin and which is associated with GDF-9. In another embodiment, the invention provides a method of treating a cell proliferative disorder associated with abnormal levels of expression of GDF-9, by suppressing or enhancing GDF-9 activity. In another embodiment, the invention provides a method for inhibiting oocyte maturation. The method includes contacting oocytes with an inhibiting effective amount of an inhibitor of GDF-9, thereby inhibiting oocyte maturation as compared to untreated oocytes. Inhibition of oocyte maturation provides contraception for fertile female subjects. The invention also provides a method for inducing an immune response in a subject to GDF-9 whereby oocyte maturation is inhibited, comprising administering to a subject GDF-9 polypeptide or immunogenic fragment thereof and inducing an anti-GDF-9 immune response in the subject. BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 shows expression of GDF-9 mRNA in adult tissues. FIGURES 2a-2c shows nucleotide and predicted amino acid sequence of GDF-9. Consensus N-glycosylation signals are denoted by plain boxes. The putative tetrabasic processing sites are denoted by stippled boxes. The in-frame termination codons upstream ofthe putative initiating ATG and the consensus polyadenylation signals are underlined. The poly A tails are not shown. Numbers indicate nucleotide position relative to the 5' end. FIGURES 3a-3b show the alignment ofthe C-terminal sequences of GDF-9 with other members of the TGF-β family. The conserved cysteine residues are shaded. Dashes denote gaps introduced in order to maximize alignment. FIGURES 4a-4b show amino acid homologies among the different members ofthe TGF- β superfamily. Numbers represent percent amino acid identities between each pair calculated from the first conserved cysteine to the C-terminus. Boxes represent homolo- gies among highly-related members within particular subgroups. FIGURES 5a-5c show the immunohistochemical localization of GDF-9 protein. Ajdacent sections of an adult ovary were either stained with hematoxylin and eosin (FIGURE 5 a) or incubated with immune (FIGURE 5 b) or pre-immune (FIGURe 5 c) serum at a dilution of 1 :500. Anti-GDF-9 antiserum was prepared by expressing the C- terminal portion of murine GDF-9 (residues 308-441) in bacteria, excising GDF-9 protein from preparative SDS gels, and immunizing rabbits. Sites of antibody binding were visualized using the Vectastain ABC kit (Vector Labs). FIGURE 6 shows a comparison ofthe predicted amino acid sequences of murine (top lines) and human (bottom lines) GDF-9. Numbers represent amino acid positions relative to the N-termini. Vertical lines represent sequence identities. Dots represent gaps introduced in order to maximize the alignment. The clear box shows the predicted proteolytic processing sites. The shaded boxes show the cysteine residues in the mature region of the proteins. The bars at the bottom show a schematic of the pre-(clear) and mature (shaded) regions of GDF-9 with the percent sequence identities between the murine and human sequences shown below. FIGURES 7a-7d show in situ hybridization to adult ovary sections using a GDF-9 RNA probe. [ 35 S]-labeled anti-sense (FIGURE 7a and 7c] or sense (FIGURE 7b and 7d) GDF- 9 RNA probes were hybridized to adjacent paraffin-embedded sections of ovaries fixed in 4% paragormaldehyde. Sections were dipped in photographic emulsion, exposed, developed, and then stained with hematoxylin and eosin. Two representative fields are shown. FIGURES 8a-8b show in situ hybridization to a postnatal day 4 ovary section using an antisense GDF-9 RNA probe. Sections were prepared as described for FIGURE 7. Following autoradiography and staining, the section was photographed under bright-field (FIGURE 8a) or dark-field (FIGURE 8b) illumination. FIGURES 9a-9b show in situ hybridization to postnatal day 8 ovary sections using an antisense (FIGURE 9a) or sense (FIGURE 9b) GDF-9 RNA probe. Sections were prepared as described for FIGURE 7. FIGURES 10a- 10b show in situ hybridization to adult oviduct sections using an antisense (FIGURE 10a) or sense (FIGURE 10b) GDF-9 RNA probe. Sections were prepared as described for FIGURE 7. FIGURES 1 la-1 lb show in situ hybridization to an adult oviduct (0.5 days following fertilization) section using an antisense GDF-9 RNA probe. Sections were prepared as described for FIGURE 7. Following autoradiography and staining, the section was photographed under bright-field (FIGURE I la) or dark-field (FIGURE l ib) illumination. DETAILED DESCRIPTION OF THE INVENTION The present invention provides a growth and differentiation factor, GDF-9 and a polynucleotide sequence encoding GDF-9. Unlike other members of the TGF-β superfamily, GDF-9 expression is highly tissue specific, being expressed in cells primarily in ovarian tissue. In one embodiment, the invention provides a method for detection of a cell proliferative disorder ofthe ovary, which is associated with GDF-9 expression. In another embodiment, the invention provides a method for treating a cell proliferative disorder associated with abnormal expression of GDF-9 by using an agent which suppresses or enhances GDF-9 activity. In another embodiment, the invention provides a method for inhibiting oocyte maturation. Due to the expression of GDF-9 in the reproductive tract, there are a variety of applications using the polypeptide, polynucleotide and antibodies of the invention, related to contraception, fertility and pregnancy. GDF-9 could play a role in regulation ofthe menstrual cycle and, therefore, could be useful in various contraceptive regimens. The TGF-β superfamily consists of multifunctionaly polypeptides that control proliferation, differentiation, and other functions in many cell types. Many of the peptides have regulatory, both positive and negative, effects on other peptide growth factors. The structural homology between the GDF-9 protein of this invention and the members of the TGF-β family, indicates that GDF-9 is a new member ofthe family of growth and differentiation factors. Based on the known activities of many ofthe other members, it can be expected that GDF-9 will also possess biological activities that will make it useful as a diagnostic and therapeutic reagent. For example, another regulatory protein that has been found to have structural homology with TGF-β is inhibin, a specific and potent polypeptide inhibitor of the pituitary secretion of FSH. Inhibin has been isolated from ovarian follicular fluid. Because of its suppression of FSH, inhibin has potential to be used as a contraceptive in both males and females. GDF-9 may possess similar biological activity since it is also an ovarian specific peptide. Inhibin has also been shown to be useful as a marker for certain ovarian tumors (Lappohn, et al, N Engl J. Med., 321:790. 1989). GDF-9 may also be useful as a marker for identifying primary and metastatic neoplasms of ovarian origin. Similarly, GDF-9 may be useful as an indicator of developmental anomalies in prenatal screening procedures. Another peptide ofthe TGF-β family is MIS, produced by the testis and responsible for the regression ofthe Mullerian ducts in the male embryo. MIS has been show to inhibit the growth of human ovarian cancer in nude mice (Donahoe, et al, Ann. Surg., 194:472. 1981). GDF-9 may function similarly and may, therefore, be useful as an anti-cancer agent, such as for the treatment of ovarian cancer. GDF-9 may also function as a growth stimulatory factor and, therefore, be useful for the survival of various cell populations in vitro. In particular, if GDF-9 plays a role in oocyte maturation, it may be useful in in vitro fertilization procedures, e.g., in enhancing the success rate. Many ofthe members ofthe TGF-β family are also important mediators of tissue repair. TGF-β has been shown to have marked effects on the formation of collagen and causes a striking angiogenic response in the newborn mouse (Roberts, et al, Proc. Natl. Acad. Sci. USA, 83:4167, 1986). GDF-9 may also have similar activities and may be useful in repair of tissue injury caused by trauma or burns for example. The term "substantially pure" as used herein refers to GDF-9 which is substantially free of other proteins, lipids, carbohydrates or other materials with which it is naturally associated. One skilled in the art can purify GDF-9 using standard techniques for protein purification. The substantially pure polypeptide will yield a single major band on a non- reducing polyacrylamide gel. The purity of the GDF-9 polypeptide can also be determined by amino-terminal amino acid sequence analysis. GDF-9 polypeptide includes functional fragments of the polypeptide, as long as the activity of GDF-9 remains. Smaller peptides containing the biological activity of GDF-9 are included in the invention. The invention provides polynucleotides encoding the GDF-9 protein. These polynucleotides include DNA, cDNA and RNA sequences which encode GDF-9. It is understood that all polynucleotides encoding all or a portion of GDF-9 are also included herein, as long as they encode a polypeptide with GDF-9 activity. Such polynucleotides include naturally occurring, synthetic, and intentionally manipulated polynucleotides. For example, GDF-9 polynucleotide may be subjected to site-directed mutagenesis. The polynucleotide sequence for GDF-9 also includes antisense sequences. The polynucleotides ofthe invention include sequences that are degenerate as a result ofthe genetic code. There are 20 natural amino acids, most of which are specified by more than one codon. Therefore, all degenerate nucleotide sequences are included in the invention as long as the amino acid sequence of GDF-9 polypeptide encoded by the nucleotide sequence is functionally unchanged. Specifically disclosed herein is a cDNA sequence for GDF-9 which is 1712 base pairs in length and contains an open reading frame beginning with a methionine codon at nucleotide 29. The encoded polypeptide is 441 amino acids in length with a molecular weight of about 49.6 kD, as determined by nucleotide sequence analysis. The GDF-9 sequence contains a core of hydrophobic amino acids near the N-terminus, suggestive of a signal sequence for secretion. GDF-9 contains four potential N-glycosylation sites at asparagine residues 163, 229, 258, and 325 and a putative tetrabasic proteolytic processing site (RRRR) at amino acids 303-306. The mature C-terminal fragment of GDF-9 is predicted to be 135 amino acids in length and have an unglycosylated molecular weight of about 15.6 kD, as determined by nucleotide sequence analysis. One skilled in the art can modify, or partially or completely remove the glycosyl groups from the GDF-9 protein using standard techniques. Therefore, the functional protein or fragments thereof of the invention includes glycosylated, partially glycosylated and unglycosylated species of GDF-9. The degree of sequence identity of GDF-9 with known TGF-β family members ranges from a minimum of 21% with Mullerian inhibiting substance (MIS) to a maximum of 34%o with bone moφhogenetic protein-4 (BMP-4). GDF-9 specifically disclosed herein differs from the known family members in its pattern of cysteine residues in the C- teπninal region. GDF-9 lacks the fourth cysteine ofthe seven cysteines present in other family members; in place of cysteine at this position, the GDF-9 sequence contains a serine residue. This GDF-9 does not contain a seventh cysteine residue elsewhere in the C-terminal region. Minor modifications ofthe recombinant GDF-9 primary amino acid sequence may result in proteins which have substantially equivalent activity as compared to the GDF-9 polypeptide described herein. Such modifications may be deliberate, as by site-directed mutagenesis, or may be spontaneous. All of the polypeptides produced by these modifications are included herein as long as the biological activity of GDF-9 still exists. Further, deletion of one or more amino acids can also result in a modification of the structure ofthe resultant molecule without significantly altering its biological activity. This can lead to the development of a smaller active molecule which would have broader utility. For example, one can remove amino or carboxy terminal amino acids which are not required for GDF-9 biological activity. The nucleotide sequence encoding the GDF-9 polypeptide ofthe invention includes the disclosed sequence and conservative variations thereof. The term "conservative variation" as used herein denotes the replacement of an amino acid residue by another, biologically similar residue. Examples of conservative variations include the substitution of one hydrophobic residue such as isoleucine, valine, leucine or methionine for another, or the substitution of one polar residue for another, such as the substitution of arginine for lysine, glutamic for aspartic acids, or glutamine for asparagine, and the like. The term "conservative variation" also includes the use of a substituted amino acid in place of an unsubstituted parent amino acid provided that antibodies raised to the substituted polypeptide also immunoreact with the unsubstituted polypeptide. DNA sequences ofthe invention can be obtained by several methods. For example, the DNA can be isolated using hybridization techniques which are well known in the art. These include, but are not limited to: 1) hybridization of genomic or cDNA libraries with probes to detect homologous nucleotide sequences and 2) antibody screening of expression libraries to detect cloned DNA fragments with shared structural features. Preferably the GDF-9 polynucleotide of the invention is derived from a mammalian organism, and most preferably from a mouse, rat, or human. Screening procedures which rely on nucleic acid hybridization make it possible to isolate any gene sequence from any organism, provided the appropriate probe is available. Oligonucleotide probes, which correspond to a part ofthe sequence encoding the protein in question, can be synthesized chemically. This requires that short, oligopeptide stretches of amino acid sequence must be known. The DNA sequence encoding the protein can be deduced from the genetic code, however, the degeneracy ofthe code must be taken into account. It is possible to perform a mixed addition reaction when the sequence is degenerate. This includes a heterogeneous mixture of denatured double-stranded DNA. For such screening, hybridization is preferably performed on either single-stranded DNA or denatured double-stranded DNA. Hybridization is particularly useful in the detection of cDNA clones derived from sources where an extremely low amount of mRNA sequences relating to the polypeptide of interest are present. In other words, by using stringent hybridization conditions directed to avoid non-specific binding, it is possible, for example, to allow the autoradiographic visualization of a specific cDNA clone by the hybridization ofthe target DNA to that single probe in the mixture which is its complete complement (Wallace, et al, Nucl. Acid Res., 9:879, 1981). The development of specific DNA sequences encoding GDF-9 can also be obtained by: 1) isolation of double-stranded DNA sequences from the genomic DNA; 2) chemical manufacture of a DNA sequence to provide the necessary codons for the polypeptide of interest; and 3) in vitro synthesis of a double-stranded DNA sequence by reverse transcription of mRNA isolated from a eukaryotic donor cell. In the latter case, a double- stranded DNA complement of mRNA is eventually formed which is generally referred to as cDNA. Of the three above-noted methods for developing specific DNA sequences for use in recombinant procedures, the isolation of genomic DNA isolates is the least common. This is especially true when it is desirable to obtain the microbial expression of mammalian polypeptides due to the presence of introns. The synthesis of DNA sequences is frequently the method of choice when the entire sequence of amino acid residues ofthe desired polypeptide product is known. When the entire sequence of a ino acid residues ofthe desired polypeptide is not known, the direct synthesis of DNA sequences is not possible and the method of choice is the synthesis of cDNA sequences. Among the standard procedures for isolating cDNA sequences of interest is the formation of plasmid- or phage-carrying cDNA libraries which are derived from reverse transcription of mRNA which is abundant in donor cells that have a high level of genetic expression. When used in combination with polymerase chain reaction technology, even rare expression products can be cloned. In those cases where significant portions of the amino acid sequence of the polypeptide are known, the production of labeled single or double-stranded DNA or RNA probe sequences duplicating a sequence putatively present in the target cDNA may be employed in DN A/DNA hybridization procedures which are carried out on cloned copies of the cDNA which have been denatured into a single-stranded form (Jay, et al, Nucl Acid Res., il:2325, 1983). A cDNA expression library, such as lambda gtl 1 , can be screened indirectly for GDF-9 peptides having at least one epitope, using antibodies specific for GDF-9. Such antibodies can be either polyclonally or monoclonally derived and used to detect expression product indicative ofthe presence of GDF-9 cDNA. DNA sequences encoding GDF-9 can be expressed in vitro by DNA transfer into a suitable host cell. "Host cells" are cells in which a vector can be propagated and its DNA expressed. The term also includes any progeny ofthe subject host cell. It is understood that all progeny may not be identical to the parental cell since there may be mutations that occur during replication. However, such progeny are included when the term "host cell" is used. Methods of stable transfer, meaning that the foreign DNA is continuously maintained in the host, are known in the art. In the present invention, the GDF-9 polynucleotide sequences may be inserted into a recombinant expression vector. The term "recombinant expression vector" refers to a plasmid, virus or other vehicle known in the art that has been manipulated by insertion or incoφoration of the GDF-9 genetic sequences. Such expression vectors contain a promoter sequence which facilitates the efficient transcription of the inserted genetic sequence ofthe host. The expression vector typically contains an origin of replication, a promoter, as well as specific genes which allow phenotypic selection of the transformed cells. Vectors suitable for use in the present invention include, but are not limited to the T7 -based expression vector for expression in bacteria (Rosenberg, et al, Gene ,56:125, 1987), the pMSXND expression vector for expression in mammalian cells (Lee and Nathans, J. Biol Chem., 263:3521, 1988) and baculovirus-derived vectors for expression in insect cells. The DNA segment can be present in the vector operably linked to regulatory elements, for example, a promoter (e.g., T7, metallothionein I, or polyhedrin promoters). Polynucleotide sequences encoding GDF-9 can be expressed in either prokaryotes or eukaryotes. Hosts can include microbial, yeast, insect and mammalian organisms. Methods of expressing DNA sequences having eukaryotic or viral sequences in prokaryotes are well known in the art. Biologically functional viral and plasmid DNA vectors capable of expression and replication in a host are known in the art. Such vectors are used to incoφorate DNA sequences ofthe invention. Transformation of a host cell with recombinant DNA may be carried out by conventional techniques as are well known to those skilled in the art. Where the host is prokaryotic, such as E. coli, competent cells which are capable of DNA uptake can be prepared from cells harvested after exponential growth phase and subsequently treated by the CaCl 2 method using procedures well known in the art. Alternatively, MgCl 2 or RbCl can be used. Transformation can also be performed after forming a protoplast ofthe host cell if desired. When the host is a eukaryote, such methods of transfection of DNA as calcium phosphate co-precipitates, conventional mechanical procedures such as micro injection, electroporation, insertion of a plasmid encased in liposomes, or virus vectors may be used. Eukaryotic cells can also be cotransformed with DNA sequences encoding the GDF-9 of the invention, and a second foreign DNA molecule encoding a selectable phenotype, such as the heφes simplex thymidine kinase gene. Another method is to use a eukaryotic viral vector, such as simian virus 40 (SV40) or bovine papilloma virus, to transiently infect or transform eukaryotic cells and express the protein, (see for example, Eukaryotic Viral Vectors, Cold Spring Harbor Laboratory, Gluzman ed., 1982). Isolation and purification of microbial expressed polypeptide, or fragments thereof, provided by the invention, may be carried out by conventional means including preparative chromatography and immunological separations involving monoclonal or polyclonal antibodies. 5 The invention includes antibodies immunoreactive with GDF-9 polypeptide or functional fragments thereof. Antibody which consists essentially of pooled monoclonal antibodies with different epitopic specificities, as well as distinct monoclonal antibody preparations are provided. Monoclonal antibodies are made from antigen containing fragments ofthe protein by methods well known to those skilled in the art (Kohler, et al, Nature, 10 256:495. 1975). The term antibody as used in this invention is meant to include intact molecules as well as fragments thereof, such as Fab and F(ab') 2 , which are capable of binding an epitopic determinant on GDF-9. The preparation of polyclonal antibodies is well-known to those skilled in the art. See, for example, Green et al. , Production of Polyclonal Antisera, in IMMUNOCHEMICAL 15 PROTOCOLS (Manson, ed.), pages 1-5 (Humana Press 1992); Coligan et al. , Production of Polyclonal Antisera in Rabbits, Rats, Mice and Hamsters, in CURRENT PROTOCOLS IN EVMUNOLOGY, section 2.4.1 (1992), which are hereby incoφorated by reference. The preparation of monoclonal antibodies likewise is conventional. See, for example, 20 Kohler & Milstein, Nature 256:495 (1975); Coligan et al, sections 2.5.1-2.6.7; and Harlow et al, ANTIBODIES: A LABORATORY MANUAL, page 726 (Cold Spring Harbor Pub. 1988), which are hereby incoφorated by reference. Briefly, monoclonal antibodies can be obtained by injecting mice with a composition comprising an antigen, verifying the presence of antibody production by removing a serum sample, removing 25 the spleen to obtain B lymphocytes, fusing the B lymphocytes with myeloma cells to produce hybridomas, cloning the hybridomas, selecting positive clones that produce antibodies to the antigen, and isolating the antibodies from the hybridoma cultures. Monoclonal antibodies can be isolated and purified from hybridoma cultures by a variety of well-established techniques. Such isolation techniques include affinity chromatography with Protein-A Sepharose, size-exclusion chromatography, and ion- exchange chromatography. See, e.g., Coligan et al, sections 2.7.1-2.7.12 and sections 2.9.1 -2.9.3 ; Barnes et al , Purification of Immunoglobulin G (IgG), in METHODS IN MOLECULAR BIOLOGY, VOL. 10, pages 79-104 (Humana Press 1992). Methods of in vitro and in vivo multiplication of monoclonal antibodies is well-known to those skilled in the art. Multiplication in vitro may be carried out in suitable culture media such as Dulbecco's Modified Eagle Medium or RPMI 1640 medium, optionally replenished by a mammalian serum such as fetal calf serum or trace elements and growth-sustaining supplements such as normal mouse peritoneal exudate cells, spleen cells, bone marrow macrophages. Production in vitro provides relatively pure antibody preparations and allows scale-up to yield large amounts ofthe desired antibodies. Large scale hybridoma cultivation can be carried out by homogenous suspension culture in an airlift reactor, in a continuous stirrer reactor, or in immobilized or entrapped cell culture. Multiplication in vivo may be carried out by injecting cell clones into mammals histocompatible with the parent cells, e.g., osyngeneic mice, to cause growth of antibody- producing tumors. Optionally, the animals are primed with a hydrocarbon, especially oils such as pristane (tetramethylpentadecane) prior to injection. After one to three weeks, the desired monoclonal antibody is recovered from the body fluid ofthe animal. Therapeutic applications for antibodies disclosed herein are also part of the present invention. For example, antibodies ofthe present invention may also be derived from subhuman primate antibody. General techniques for raising therapeutically useful antibodies in baboons can be found, for example, in Goldenberg et al. , International Patent Publication WO 91/11465 (1991) and Losman et al. , Int. J. Cancer 46:310 (1990), which are hereby incoφorated by reference. A therapeutically useful anti-GDF-9 antibody may be derived from a "humanized" monoclonal antibody. Humanized monoclonal antibodies are produced by transferring mouse complementarity determining regions from heavy and light variable chains ofthe mouse immunoglobulin into a human variable domain, and then substituting human residues in the framework regions of the murine counteφarts. The use of antibody components derived from humanized monoclonal antibodies obviates potential problems associated with the immunogenicity of murine constant regions. General techniques for cloning murine immunoglobulin variable domains are described, for example, by Orlandi et al, Proc. Nat'l Acad. Sci. USA 86:3833 (1989), which is hereby incoφorated in its entirety by reference. Techniques for producing humanized monoclonal antibodies are described, for example, by Jones et al, Nature 321 : 522 (1986); Riechmann et al, Nature 332: 323 (1988); Verhoeyen et al, Science 239: 1534 (1988); Carter et al, Proc. Nat'l Acad. Sci. USA 89: 4285 (1992); Sandhu, Crit. Rev. Biotech. 12: 437 (1992); and Singer et al, J. Immunol 150: 2844 (1993), which are hereby incoφorated by reference. Antibodies ofthe invention also may be derived from human antibody fragments isolated from a combinatorial immunoglobulin library. See, for example, Barbas et al, METHODS: A COMPANION TO METHODS IN ENZYMOLOGY, VOL. 2, page 119 (1991); Winter etal,Ann. Rev. Immunol. 12: 433 (1994), which are hereby incoφorated by reference. Cloning and expression vectors that are useful for producing a human immunoglobulin phage library can be obtained, for example, from STRATAGENE Cloning Systems (La Jolla, CA). In addition, antibodies ofthe present invention may be derived from a human monoclonal antibody. Such antibodies are obtained from transgenic mice that have been "engineered" to produce specific human antibodies in response to antigenic challenge. In this technique, elements ofthe human heavy and light chain loci are introduced into strains of mice derived from embryonic stem cell lines that contain targeted disruptions ofthe endogenous heavy and light chain loci. The transgenic mice can synthesize human antibodies specific for human antigens, and the mice can be used to produce human antibody-secreting hybridomas. Methods for obtaining human antibodies from transgenic mice are described by Green et al. , Nature Genet. 7:13 (1994); Lonberg et al. , Nature 368:856 (1994); and Taylor et al, Int. Immunol. 6:579 (1994), which are hereby incoφorated by reference. Antibody fragments of the present invention can be prepared by proteolytic hydrolysis of the antibody or by expression in E. coli of DNA encoding the fragment. Antibody fragments can be obtained by pepsin or papain digestion of whole antibodies by conventional methods. For example, antibody fragments can be produced by enzymatic cleavage of antibodies with pepsin to provide a 5S fragment denoted F(ab') 2 . This fragment can be further cleaved using a thiol reducing agent, and optionally a blocking group for the sulfhydryl groups resulting from cleavage of disulfide linkages, to produce 3.5S Fab' monovalent fragments. Alternatively, an enzymatic cleavage using pepsin produces two monovalent Fab' fragments and an Fc fragment directly. These methods are described, for example, by Goldenberg, U.S. patents No. 4,036,945 and No. 4,331 ,647, and references contained therein. These patents are hereby incoφorated in their entireties by reference. See also Nisonhoff et al, Arch. Biochem. Biophys. 89:230 (1960); Porter, Biochem. J. 73:119 (1959); Εdelman et al, METHODS IN ENZYMOLOGY, VOL. 1, page 422 (Academic Press 1967); and Coligan et al at sections 2.8.1-2.8.10 and 2.10.1-2.10.4. Other methods of cleaving antibodies, such as separation of heavy chains to form monovalent light-heavy chain fragments, further cleavage of fragments, or other enzymatic, chemical, or genetic techniques may also be used, so long as the fragments bind to the antigen that is recognized by the intact antibody. For example, Fv fragments comprise an association of V H and Y chains. This association may be noncovalent, as described in Inbar et al. , Proc. Nat'l Acad. Sci. USA 69:2659 (1972). Alternatively, the variable chains can be linked by an intermolecular disulfide bond or cross-linked by chemicals such as glutaraldehyde. See, e.g., Sandhu, supra. Preferably, the Fv fragments comprise V H and V L chains connected by a peptide linker. These single-chain antigen binding proteins (sFv) are prepared by constructing a structural gene comprising DNA sequences encoding the V H and V L domains connected by an oligonucleotide. The structural gene is inserted into an expression vector, which is subsequently introduced into a host cell such as E. coli. The recombinant host cells synthesize a single polypeptide chain with a linker peptide bridging the two V domains. Methods for producing sFvs are described, for example, by Whitlow et al, METHODS: A COMPANION TO METHODS IN ENZYMOLOGY, VOL. 2, page 97 (1991); Bird et al, Science 242:423-426 (1988); Ladner et al, U.S. patent No. 4,946,778; Pack et al, Bio/Technology 11: 1271-77 (1993); and Sandhu, supra. Another form of an antibody fragment is a peptide coding for a single complementarity- determiriing region (CDR). CDR peptides ("minimal recognition units") can be obtained by constructing genes encoding the CDR of an antibody of interest. Such genes are prepared, for example, by using the polymerase chain reaction to synthesize the variable region from RNA of antibody-producing cells. See, for example, Larrick et al, METHODS: A COMPANION TO METHODS IN ENZYMOLOGY, VOL. 2, page 106 (1991). The term "cell-proliferative disorder" denotes malignant as well as non-malignant cell populations which often appear to differ from the surrounding tissue both moφhologically and genotypically. The GDF-9 polynucleotide that is an antisense molecule is useful in treating malignancies ofthe various organ systems, particularly, for example, the ovaries. Essentially, any disorder which is etiologically linked to altered expression of GDF-9 could be considered susceptible to treatment with a GDF-9 suppressing reagent. The invention provides a method for detecting a cell proliferative disorder ofthe ovary which comprises contacting an anti-GDF-9 antibody with a cell suspected of having a GDf -9 associated disorder and detecting binding to the antibody. The antibody reactive with GDF-9 is labeled with a compound which allows detection of binding to GDF-9. For puφoses ofthe invention, an antibody specific for GDF-9 polypeptide may be used to detect the level of GDF-9 in biological fluids and tissues. Any specimen containing a detectable amount of antigen can be used. A preferred sample of this invention is tissue of ovarian origin, specifically tissue containing granulosa cells or ovarian follicular fluid. The level of GDF-9 in the suspect cell can be compared with the level in a normal cell to determine whether the subject has a GDF-9-associated cell proliferative disorder. Preferably the subject is human. In another embodiment, the invention provides a contraceptive method which includes inhibiting oocyte maturation. The method comprises contacting oocytes with an inhibiting effective amount of an inhibitor of GDF-9, thereby inhibiting oocyte maturation as compared to untreated oocytes. The term Zinhibiting effective amount" as used herein means that amount of an inhibitor of GDF-9 that reduces maturation of an oocyte by about 50%>, more preferably by about 75%, and most preferably by about 95%>. One of skill in the art could use any of several methods for determining whether the amount of inhibitor of GDF-9 is effective. For example, maturation of an oocyte results in ovulation, therefore, prevention of ovulation is indicative of an effective amount. For a period just prior to ovulation, a female's body temperature increases, indicating a fertile period. An absence of a change in body temperature is indicative of prevention of oocyte maturation. Alternatively, one could measure the level of serum progesterone (see Example 6) in the subject prior to and following treatment with the inhibitor of GDF-9, where a low level of progesterone maintained throughout the period is indicative of inhibition of maturation. Levels of lutinizing hormone (LH) generally increase at the time of ovulation as well, and continuous low levels of LH can serve as an indicator of inhibition of maturation of oocytes as well. Other events associated with ovulation can be monitored in a similar manner and will be known to those of skill in the art. An "inhibitor of GDF-9" as used herein, refers to GDF-antibodies or fragments thereof as described above, antisense molecules, or peptide or peptidomimetics of GDF-9 polypeptide, for example. Other small molecules or chemical compounds may also be GDF-9 inhibitors. Also included are compounds identified using combinatorial chemistry methods for identifying chemical compounds that bind to GDF-9 or GDF-9 receptor. Preferably, when the inhibitor is a GDF-9 antibody or fragment thereof, the antibody is administered in a dose range of 0.1 ug to 100 mg. Preferably, the inhibitor is administered in vivo and preferably, the subject is a mammal, such as a human. The term "contacting" refers to administering the GDF-9 inhibitor in such a way that the inhibitor inhibits GDF-9. Methods of administration are described in detail below. The method ofthe invention is also useful for inducing an immune response in a subject to GDF-9 whereby oocyte maturation is inhibited, comprising administering to a subject GDF-9 polypeptide or immunogenic fragment thereof and inducing an anti-GDF-9 immune response in the subject. Methods of producing immunogenic fragments of a polypeptide are well known in the art. Polypeptides or peptides, including GDF-9 variants useful for the present invention comprise analogs, homologs, muteins and mimetics of GDF-9 that retain the ability to induce a specific immune response to GDF-9 or to inhibit oocyte maturation. Peptides of GDF-9 refer to portions of the amino acid sequence of GDF-9 that also retain this ability. The variants can be generated directly from GDF-9 itself by chemical modification, by proteolytic enzyme digestion, or by combinations thereof. Additionally, genetic engineering techniques, as well as methods of synthesizing polypeptides directly from amino acid residues, can be employed. Peptides ofthe invention can be synthesized by such commonly used methods as t-BOC or FMOC protection of alpha-amino groups. Both methods involve stepwise syntheses whereby a single amino acid is added at each step starting from the C terminus of the peptide (See, Coligan, et al, Current Protocols in Immunology, Wiley Interscience, 1991, Unit 9). Peptides ofthe invention can also be synthesized by the well known solid phase peptide synthesis methods described Merrifield, J. Am. Chem. Soc, 85:2149, 1962), and Stewart and Young, Solid Phase Peptides Synthesis, (Freeman, San Francisco, 1969, pp.27-62), using a copoly(styrene-divinylbenzene) containing 0.1-1.0 mMol amines/g polymer. On completion of chemical synthesis, the peptides can be deprotected and cleaved from the polymer by treatment with liquid HF-10% anisole for about 1/4-1 hours at 0°C. After evaporation of the reagents, the peptides are extracted from the polymer with 1%> acetic acid solution which is then lyophilized to yield the crude material. This can normally be purified by such techniques as gel filtration on Sephadex G-15 using 5% acetic acid as a solvent. Lyophilization of appropriate fractions ofthe column will yield the homogeneous peptide or peptide derivatives, which can then be characterized by such standard techniques as amino acid analysis, thin layer chromatography, high performance liquid chromatography, ultraviolet absoφtion spectroscopy, molar rotation, solubility, and quantitated by the solid phase Edman degradation. Alternatively, peptides can be produced by recombinant methods. The term "substantially purified" as used herein refers to a molecule, such as a peptide that is substantially free of other proteins, lipids, carbohydrates, nucleic acids, and other biological materials with which it is naturally associated. For example, a substantially pure molecule, such as a polypeptide, can be at least 60%, by dry weight, the molecule of interest. One skilled in the art can purify GDF-9 peptides using standard protein purification methods and the purity ofthe polypeptides can be determined using standard methods including, e.g., polyacrylamide gel electrophoresis (e.g., SDS-PAGE), column chromatography (e.g., high performance liquid chromatography (HPLC)), and amino-terminal amino acid sequence analysis. Non-peptide compounds that mimic the binding and function of GDF-9 ("mimetics") can be produced by the approach outlined in Saragovi et al, Science 253: 792-95 (1991). Mimetics are molecules which mimic elements of protein secondary structure. See, for example, Johnson et al, "Peptide Turn Mimetics," in BIOTECHNOLOGY AND PHARMACY, Pezzuto et al, Eds., (Chapman and Hall, New York 1993). The underlying rationale behind the use of peptide mimetics is that the peptide backbone of proteins exists chiefly to orient amino acid side chains in such a way as to facilitate molecular interactions. For the puφoses ofthe present invention, appropriate mimetics can be considered to be the equivalent of GDF-9 itself. Longer peptides can be produced by the "native chemical" ligation technique which links together peptides (Dawson, et al, Science, 266:776, 1994). Variants can be created by recombinant techniques employing genomic or cDNA cloning methods. Site-specific and region-directed mutagenesis techniques can be employed. See CURRENT PROTOCOLS IN MOLECULAR BIOLOGY vol. 1, ch. 8 (Ausubel et al. eds., J. Wiley & Sons 1989 & Supp. 1990-93); PROTEIN ENGINEERING (Oxender & Fox eds., A. Liss, Inc. 1987). In addition, linker-scanning and PCR-mediated techniques can be employed for mutagenesis. See PCR TECHNOLOGY (Erlich ed., Stockton Press 1989); CURRENT PROTOCOLS IN MOLECULAR BIOLOGY, vols. 1 & 2, supra. Protein sequencing, structure and modeling approaches for use with any ofthe above techniques are disclosed in PROTEIN ENGINEERING, loc. cit., and CURRENT PROTOCOLS IN MOLECULAR BIOLOGY, vols. 1 & 2, supra. The invention also includes various pharmaceutical compositions that prevent maturation of an oocyte. The pharmaceutical compositions according to the invention are prepared by bringing an antibody against GDF-9, a peptide or peptide derivative of GDF-9, a GDF-9 mimetic, or a GDF-9-binding agent according to the present invention into a form suitable for administration to a subject using carriers, excipients and additives or auxiliaries. Frequently used carriers or auxiliaries include magnesium carbonate, titanium dioxide, lactose, mannitol and other sugars, talc, milk protein, gelatin, starch, vitamins, cellulose and its derivatives, animal and vegetable oils, polyethylene glycols and solvents, such as sterile water, alcohols, glycerol and polyhydric alcohols. Intravenous vehicles include fluid and nutrient replenishers. Preservatives include antimicrobial, anti-oxidants, chelating agents and inert gases. Other pharmaceutically acceptable carriers include aqueous solutions, non-toxic excipients, including salts, preservatives, buffers and the like, as described, for instance, in Remington's Pharmaceutical Sciences, 15th ed. Easton: Mack Publishing Co., 1405-1412, 1461- 1487 (1975) and The National Formulary XIV., 14th ed. Washington: American Pharmaceutical Association (1975), the contents of which are hereby incoφorated by reference. The pH and exact concentration of the various components of the pharmaceutical composition are adjusted according to routine skills in the art. See Goodman and Gilman's The Pharmacological Basis for Therapeutics (7th ed.). The methods involves administering to a subject a therapeutically or inhibiting effective dose of a pharmaceutical composition containing the compounds ofthe present invention and a pharmaceutically acceptable carrier. "Administering" the pharmaceutical composition of the present invention may be accomplished by any means known to the skilled artisan. By "subject" is meant any mammal, preferably a human. The pharmaceutical compositions are preferably prepared and administered in dose units. Solid dose units are tablets, capsules and suppositories. For treatment of a patient, depending on activity of the compound, manner of administration, nature and severity of the disorder, age and body weight ofthe patient, different daily doses are necessary. Under certain circumstances, however, higher or lower daily doses may be appropriate. The administration ofthe daily dose can be carried out both by single administration in the form of an individual dose unit or else several smaller dose units and also by multiple administration of subdivided doses at specific intervals. The pharmaceutical compositions according to the invention are in general administered topically, intravenously, orally or parenterally or as implants, but even rectal use is possible in principle. Suitable solid or liquid pharmaceutical preparation forms are, for example, granules, powders, tablets, coated tablets, (micro)capsules, suppositories, syrups, emulsions, suspensions, creams, aerosols, drops or injectable solution in ampule * form and also preparations with protracted release of active compounds, in whose preparation excipients and additives and/or auxiliaries such as disintegrants, binders, coating agents, swelling agents, lubricants, flavorings, sweeteners or solubilizers are customarily used as described above. The pharmaceutical compositions are suitable for use in a variety of drug delivery systems. For a brief review of present methods for drug delivery, see Langer, Science, 249: 1527-1533 (1990), which is incoφorated herein by reference. The pharmaceutical compositions according to the invention may be administered locally or systemically. By "therapeutically effective dose" is meant the quantity of a compound according to the invention necessary to prevent, to cure or at least partially arrest the symptoms of the disease and its complications. An "inhibiting effective amount" of GDF-9 inhibitor has been defined above for use as in contraception regimes. Amounts effective for this use will, of course, depend on the severity of the disease and the weight and general state of the patient. Typically, dosages used in vitro may provide useful guidance in the amounts useful for in situ administration of the pharmaceutical composition, and animal models may be used to determine effective dosages for treatment of particular disorders. Various considerations are described, e.g., in Gilman et al. (eds.) (1990) GOODMAN AND GILMAN'S: THE PHARMACOLOGICAL BASES OF THERAPEUTICS, 8th ed., Pergamon Press; and REMINGTON'S PHARMACEUTICAL SCIENCES, 17th ed. (1990), Mack Publishing Co., Easton, Pa., each of which is herein incoφorated by reference. The pharmaceutical compositions of the invention may also be delivered by a slow release vehicle. Compounds of the invention can be further diluted by addition of suspending medium or other biologically acceptable carrier to obtain injectable or implantable slow release formulations of any therapeutically effective total dosage. One approach which has been used to provide controlled release compositions for drug delivery is liposome encapsulation. Among the main types of liposomes, multivesicular liposomes (Kim, et al, Biochim. Biophys. Acta; 728:339-348, 1983), are uniquely different from unilamellar liposomes (Huang, Biochemistry; 8:334-352, 1969; Kim, et al, Biochim. Biophys. Acta; 646:1-10. 1981), multilamellar liposomes (Bangham, et al, J. Mol. Bio., 13:238-252, 1965), and stable plurilamellar liposomes (U.S. Patent No. 4,522,803). U.S. Patent No. 5,077,056 discloses studies that show the rate of release of the encapsulated biological agent from liposomes into an aqueous environment can be modulated by introducing protonophores or ionophores into liposomes to create a membrane potential. In addition, a method is known (U.S. Patent No. 5,186,941) for controlling the release rate of drugs from vesicle compositions wherein the liposomes containing a therapeutic agent encapsulated are suspended in a solution containing sufficient solute to provide an osmolarity substantially isotonic with respect to that ofthe solution within the vesicles, and hypertonic with respect to physiological saline. In multivesicular liposomes, it is also known (WO 96/08253) to control the rate of release of active agents by introducing an osmotic spacer into the aqueous solution in which the active agent is dissolved prior to formation ofthe multivesicular liposomes. The antibodies of the invention can be used in any subject in which it is desirable to administer in vitro or in vivo immunodiagnosis or immunotherapy. The antibodies ofthe invention are suited for use, for example, in immunoassays in which they can be utilized in liquid phase or bound to a solid phase carrier. In addition, the antibodies in these immunoassays can be detectably labeled in various ways. Examples of types of immunoassays which can utilize antibodies of the invention are competitive and non- competitive immunoassays in either a direct or indirect format. Examples of such immunoassays are the radioirnmunoassay (RIA) and the sandwich (immunometric) assay. Detection of the antigens using the antibodies of the invention can be done utilizing immunoassays which are run in either the forward, reverse, or simultaneous modes, including immunohistochemical assays on physiological samples. Those of skill in the art will know, or can readily discern, other immunoassay formats without undue experimentation. The antibodies of the invention can be bound to many different carriers and used to detect the presence of an antigen comprising the polypeptide ofthe invention. Examples of well-known carriers include glass, polystyrene, polypropylene, polyethylene, dextran, nylon, amylases, natural and modified celluloses, polyacrylamides, agaroses and magnetite. The nature ofthe carrier can be either soluble or insoluble for puφoses ofthe invention. Those skilled in the art will know of other suitable carriers for binding antibodies, or will be able to ascertain such, using routine experimentation. There are many different labels and methods of labeling known to those of ordinary skill in the art. Examples ofthe types of labels which can be used in the present invention include enzymes, radioisotopes, fluorescent compounds, colloidal metals, chemiluminescent compounds, phosphorescent compounds, and bioluminescent compounds. Those of ordinary skill in the art will know of other suitable labels for binding to the antibody, or will be able to ascertain such, using routine experimentation. Another technique which may also result in greater sensitivity consists of coupling the antibodies to low molecular weight haptens. These haptens can then be specifically detected by means of a second reaction. For example, it is common to use such haptens as biotin, which reacts with avidin, or dinitrophenyl, puridoxal, and fluorescein, which can react with specific antihapten antibodies. In using the monoclonal antibodies ofthe invention for the in vivo detection of antigen, the detectably labeled antibody is given a dose which is diagnostically effective. The term "diagnostically effective" means that the amount of detectably labeled monoclonal antibody is administered in sufficient quantity to enable detection ofthe site having the antigen comprising a polypeptide ofthe invention for which the monoclonal antibodies are specific. The concentration of detectably labeled monoclonal antibody which is adminstered should be sufficient such that the binding to those cells having the polypeptide is detectable compared to the background. Further, it is desirable that the detectably labeled monoclonal antibody be rapidly cleared from the circulatory system in order to give the best target-to-background signal ratio. As a rule, the dosage of detectably labeled monoclonal antibody for in vivo diagnosis will vary depending on such factors as age, sex, and extent of disease ofthe individual. Such dosages may vary, for example, depending on whether multiple injections are given, antigenic burden, and other factors known to those of skill in the art. For in vivo diagnostic imaging, the type of detection instrument available is a major factor in selecting a given radioisotope. The radioisotope chosen must have a type of decay which is detectable for a given type of instrument. Still another important factor in selecting a radioisotope for in vivo diagnosis is that deleterious radiation with respect to the host is minimized. Ideally, a radioisotope used for in vivo imaging will lack a particle emission, but produce a large number of photons in the 140-250 keV range, which may readily be detected by conventional gamma cameras. For in vivo diagnosis radioisotopes may be bound to immunoglobulin either directly or indirectly by using an intermediate functional group. Intermediate functional groups which often are used to bind radioisotopes which exist as metallic ions to immunoglobulins are the bifiinctional chelating agents such as diethylenetriaminepentacetic acid (DTP A) and ethylenediaminetetraacetic acid (EDTA) and similar molecules. Typical examples of metallic ions which can be bound to the monoclonal antibodies ofthe invention are ι π In, 97 Ru, 67 Ga, 68 Ga, 72 As, 89 Zr, and 201 T1. The monoclonal antibodies of the invention can also be labeled with a paramagnetic isotope for puφoses of in vivo diagnosis, as in magnetic resonance imaging (MRJ) or electron spin resonance (ESR). In general, any conventional method for visualizing diagnostic imaging can be utilized. Usually gamma and positron emitting radioisotopes are used for camera imaging and paramagnetic isotopes for MRI. Elements which are particularly useful in such techniques include 157 Gd, 55 Mn, 162 Dy, 52 Cr, and 56 Fe. The monoclonal antibodies ofthe invention can be used in vitro and in vivo to monitor the course of amelioration of a GDF-9-associated disease in a subject. Thus, for example, by measuring the increase or decrease in the number of cells expressing antigen comprising a polypeptide ofthe invention or changes in the concentration of such antigen present in various body fluids, it would be possible to determine whether a particular therapeutic regimen aimed at ameliorating the GDF-9-associated disease is effective. The term "ameliorate" denotes a lessening of the detrimental effect of the GDF-9- associated disease in the subject receiving therapy. Similarly, such techniques can be used to follow a contraceptive regime in a subject. The present invention identifies a nucleotide sequence that can be expressed in an altered manner as compared to expression in a normal cell, therefore, it is possible to design appropriate therapeutic or diagnostic techniques directed to this sequence. Thus, where a cell-proliferative disorder is associated with the expression of GDF-9, nucleic acid sequences that interfere with GDF-9 expression at the translational level can be used. This approach utilizes, for example, antisense nucleic acid and ribozymes to block translation of a specific GDF-9 mRNA, either by masking that mRNA with an antisense nucleic acid or by cleaving it with a ribozyme. In addition, antisense molecules or ribozymes are useful in the contraceptive methods ofthe invention where it is desirable to inhibit GDF-9 expression. As a further mechanism of action, in "transcription arrest" it appears that some polynucleotides can form "triplex," or triple-helical structures with double stranded genomic DNA containing the gene of interest, thus interfering with transcription by RNA polymerase. Giovannangeli et al, Proc. Natl. Acad. Sci. 90:10013 (1993); Ebbinghaus et al. J. Clin. Invest. 92:2433 (1993). Antisense nucleic acids are DNA or RNA molecules that are complementary to at least a portion of a specific mRNA molecule (Weintraub, Scientific American, 262:40, 1990). In the cell, the antisense nucleic acids hybridize to the corresponding mRNA, forming a double-stranded molecule. The antisense nucleic acids interfere with the translation of the mRNA, since the cell will not translate a mRNA that is double-stranded. Antisense oligomers of about 15 nucleotides are preferred, since they are easily synthesized and are less likely to cause problems than larger molecules when introduced into the target GDF-9-producing cell. The use of antisense methods to inhibit the in vitro translation of genes is well known in the art (Marcus-Sakura, Anal. Biochem. , 172:289, 1988). Ribozymes are RNA molecules possessing the ability to specifically cleave other single- stranded RNA in a manner analogous to DNA restriction endonucleases. Through the modification of nucleotide sequences which encode these RNAs, it is possible to engineer molecules that recognize specific nucleotide sequences in an RNA molecule and cleave it (Cech, J.Amer.Med. Assn., 260:3030, 1988). A major advantage of this approach is that, because they are sequence-specific, only mRNAs with particular sequences are inactivated. There are two basic types of ribozymes namely, tetrahymena-type (Hasselhoff, Nature, 334:585, 1988) and "hammerhead"-type. Tetrahymena-type ribozymes recognize sequences which are four bases in length, while "hammerhead"-type ribozymes recognize base sequences 11-18 bases in length. The longer the recognition sequence, the greater the likelihood that the sequence will occur exclusively in the target mRNA species. Consequently, hammerhead-type ribozymes are preferable to tetrahymena- ype ribozymes for inactivating a specific mRNA species and 18-based recognition sequences are preferable to shorter recognition sequences. The present invention also provides gene therapy for the treatment of cell proliferative disorders which are mediated by GDF-9 protein or where it is desirable to inhibit GDF-9 expression for puφoses of contraception. Such therapy would achieve its therapeutic effect by introduction of the GDF-9 antisense polynucleotide into cells having the proliferative disorder or introduction of antisense into oocytes. Delivery of antisense or sense GDF-9 polynucleotide, GDF-9 polypeptide or peptides can be achieved using a recombinant expression vector such as a chimeric virus or a colloidal dispersion system. Especially preferred for therapeutic delivery of antisense sequences is the use of targeted liposomes. Various viral vectors which can be utilized for gene therapy as taught herein include adenovirus, heφes virus, vaccinia, or, preferably, an RNA virus such as a retrovirus. Preferably, the retroviral vector is a derivative of a murine or avian retrovirus. Examples of retroviral vectors in which a single foreign gene can be inserted include, but are not limited to: Moloney murine leukemia virus (MoMuLV), Harvey murine sarcoma virus (HaMuSV), murine mammary tumor virus (MuMTV), and Rous Sarcoma Virus (RSV). A number of additional retroviral vectors can incoφorate multiple genes. All of these vectors can transfer or incoφorate a gene for a selectable marker so that transduced cells can be identified and generated. By inserting a GDF-9 sequence of interest into the viral vector, along with another gene which encodes the ligand for a receptor on a specific target cell, for example, the vector is now target specific. Retroviral vectors can be made target specific by inserting, for example, a polynucleotide encoding a sugar, a glycolipid, or a protein. Preferred targeting is accomplished by using an antibody to target the retroviral vector. Those of skill in the art will know of, or can readily ascertain without undue experimentation, specific polynucleotide sequences which can be inserted into the retroviral genome to allow target specific delivery ofthe retroviral vector containing the GDF-9 antisense polynucleotide. Since recombinant retroviruses are defective, they require assistance in order to produce infectious vector particles. This assistance can be provided, for example, by using helper cell lines that contain plasmids encoding all ofthe structural genes ofthe retrovirus under the control of regulatory sequences within the LTR. These plasmids are missing a nucleotide sequence which enables the packaging mechanism to recognize an RNA transcript for encapsidation. Helper cell lines which have deletions of the packaging signal include, but are not limited to Ψ2, PA317 and PA12, for example. These cell lines produce empty virions, since no genome is packaged. If a retroviral vector is introduced into such cells in which the packaging signal is intact, but the structural genes are replaced by other genes of interest, the vector can be packaged and vector virion produced. Alternatively, NIH 3T3 or other tissue culture cells can be directly transfected with plasmids encoding the retroviral structural genes gag, pol and env, by conventional calcium phosphate transfection. These cells are then transfected with the vector plasmid containing the genes of interest. The resulting cells release the retroviral vector into the culture medium. Another targeted delivery system for GDF-9 polynucleotides or polypeptides is a colloidal dispersion system. Colloidal dispersion systems include macromolecule complexes, nanocapsules, microspheres, beads, and lipid-based systems including oil-in- water emulsions, micelles, mixed micelles, and liposomes. The preferred colloidal system of this invention is a liposome. Liposomes are artificial membrane vesicles which are useful as delivery vehicles in vitro and in vivo. It has been shown that large unilamellar vesicles (LUV), which range in size from 0.2-4.0 μm can encapsulate a substantial percentage of an aqueous buffer containing large macromolecules. RNA, DNA and intact virions can be encapsulated within the aqueous interior and be delivered to cells in a biologically active form (Fraley, et al, Trends Biochem. Sci., 6:77, 1981). In addition to mammalian cells, liposomes have been used for delivery of polynucleotides in plant, yeast and bacterial cells. In order for a liposome to be an efficient gene transfer vehicle, the following characteristics should be present: (1) encapsulation of the genes of interest at high efficiency while not compromising their biological activity; (2) preferential and substantial binding to a target cell in comparison to non-target cells; (3) delivery ofthe aqueous contents of the vesicle to the target cell cytoplasm at high efficiency; and (4) accurate and effective expression of genetic information (Mannino, et al, Biotechniques, 6:682, 1988). The composition ofthe liposome is usually a combination of phospholipids, particularly high-phase-transition-temperarure phospholipids, usually in combination with steroids, especially cholesterol. Other phospholipids or other lipids may also be used. The physical characteristics of liposomes depend on pH, ionic strength, and the presence of divalent cations. Examples of lipids useful in liposome production include phosphatidyl compounds, such as phosphatidylglycerol, phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, sphingolipids, cerebrosides, and gangliosides. Particularly useful are diacylphosphatidylglycerols, where the lipid moiety contains from 14-18 carbon atoms, particularly from 16-18 carbon atoms, and is saturated. Illustrative phospholipids include egg phosphatidylcholine, dipalmitoylphosphatidylcholine and distearoylphosphatidylcholine. The targeting of liposomes can be classified based on anatomical and mechanistic factors. Anatomical classification is based on the level of selectivity, for example, organ- specific, cell-specific, and organelle-specific. Mechanistic targeting can be distinguished based upon whether it is passive or active. Passive targeting utilizes the natural tendency of liposomes to distribute to cells of the reticulo-endothelial system (RES) in organs which contain sinusoidal capillaries. Active targeting, on the other hand, involves alteration of the liposome by coupling the liposome to a specific ligand such as a monoclonal antibody, sugar, glycolipid, or protein, or by changing the composition or size ofthe liposome in order to achieve targeting to organs and cell types other than the naturally occurring sites of localization. The surface ofthe targeted delivery system may be modified in a variety of ways. In the case of a liposomal targeted delivery system, lipid groups can be incoφorated into the lipid bilayer ofthe liposome in order to maintain the targeting ligand in stable association with the liposomal bilayer. Various linking groups can be used for joining the lipid chains to the targeting ligand. The following examples are intended to illustrate but not limit the invention. While they are typical of those that might be used, other procedures known to those skilled in the art may alternatively be used. EXAMPLE 1 IDENTIFICATION AND ISOLATION OF A NOVEL TGF-β FAMILY MEMBER To identify a new member ofthe TGF-β superfamily, degenerate oligonucleotides were designed which corresponded to two conserved regions among the known family members: one region spanning the two tryptophan residues conserved in all family members except MIS and the other region spanning the invariant cysteine residues near the C-terminus. These primers were used for polymerase chain reactions on mouse genomic DNA followed by subcloning the PCR products using restriction sites placed at the 5' ends ofthe primers, picking individual E. coli colonies carrying these subcloned inserts, and using a combination of random sequencing and hybridization analysis to eliminate known members ofthe superfamily. GDF-9 was identified from a mixture of PCR products obtained with the primers SJL160 (5'-CCGGAATTCGGITGG(G/C/A)A(G/A/T/C)(G/C/A)A(G/A/T/C) TGG(A/G)TI(A/- G)TI(T/G)CICC-3') and SJL153 (5'-CCGGAATTC(A/G)CAI(G/C)C- (A/G)CAIC(T/C)(G/A/T/C)(C/G/T)TIG(T/C)I(G/A)(T/C)CAT-3'). PCR using these primers was carried out with 2 μg mouse genomic DNA at 94 °C for 1 min, 50 °C for 2 min, and 72 °C for 2 min for 40 cycles. PCR products of approximately 280 bp were gel-purified, digested with Eco RI, gel- purified again, and subcloned in the Bluescript vector (Stratagene, San Diego, CA). Bacterial colonies carrying individual subclones were picked into 96 well microtiter plates, and multiple replicas were prepared by plating the cells onto nitrocellulose. The replicate filters were hybridized to probes representing known members ofthe family, and DNA was prepared from non-hybridizing colonies for sequence analysis. The primer combination of SJL160 and SJL153, yielded three known sequences (inhibin βB, BMP-2, and BMP-4) and one novel sequence (designated GDF-9) among 145 subclones analyzed. RNA isolation and Northern analysis were carried out as described previously (Lee,S.J., Mol Endocrinol. 4:1034, 1990). An oligo dT-primed cDNA library was prepared from 2.5-3 μg of ovary poly A-selected RNA in the lambda ZAP II vector according to the instructions provided by Stratagene. The ovary library was not amplified prior to screening. Filters were hybridized as described previously (Lee, S.-J., Proc. Natl. Acad. Sci. USA., 88:4250-4254, 1991). DNA sequencing of both strands was carried out using the dideoxy chain termination method (Sanger, et al, Proc. Natl. Acad. Sci., USA, 74:5463-5467, 1977) and a combination of the SI nuclease/exonuclease III strategy (Henikoff, S., Gene, 28:351-359, 1984) and synthetic oligonucleotide primers. EXAMPLE 2 EXPRESSION PATTERNAND SEQUENCE OF GDF-9 To determine the expression pattern of GDF-9, RNA samples prepared from a variety of adult tissues were screened by Northern analysis. Five micrograms of twice polyA- selected RNA prepared from each tissue were electrophoresed on formaldehyde gels, blotted and probed with GDF-9. As shown in Figure 1 , the GDF-9 probe detected a 1.7 kb mRNA expressed exclusively in the ovary. A mouse ovary cDNA library of 1.5 x 10 6 recombinant phage was constructed in lambda ZAP π and screened with a probe derived from the GDF-9 PCR product. The nucleotide sequence ofthe longest of nineteen hybridizing clones is shown in Figure 2. Consensus N-glycosylation signals are denoted by plain boxes. The putative tetrabasic processing sites are denoted by stippled boxes. The in-frame termination codons upstream ofthe putative initiating ATG and the consensus polyadenylation signals are underlined. The poly A tails are not shown. Numbers indicate nucleotide position relative to the 5' end. The 1712 bp sequence contains a long open reading frame beginning with a methionine codon at nucleotide 29 and potentially encoding a protein 441 amino acids in length with a molecular weight of 49.6 kD. Like other TGF-β family members, the GDF-9 sequence contains a core of hydrophobic amino acids near the N-terminus suggestive of a signal sequence for secretion. GDF-9 contains four potential N-glycosylation sites at asparagine residues 163, 229, 258, and 325 and a putative tetrabasic proteolytic process- ing site (RRRR) at amino acids 303-306. The mature C-terminal fragment of GDF-9 is predicted to be 135 amino acids in length and have an unglycosylated molecular weight of 15.6 kD. Although the C-terminal portion of GDF-9 clearly shows homology with the other family members, the sequence of GDF-9 is significantly diverged from those ofthe other family members (Figures 3 and 4). Figure 3 shows the alignment ofthe C-terminal sequences of GDF-9 with the corresponding regions of human GDF-1 (Lee, Proc. Natl. Acad. Sci. USA, 88:4250-4254, 1991), Xenopus Vg-1 (Weeks, et al, Cell, 51 861-867, 1987), human Vgr-1 (Celeste, et al, Proc. Natl. Acad. Sci. USA, 87:9843-9847, 1990), human OP-1 (Ozkaynak, et al, EMBOJ., 9:2085-2093, 1990), human BMP-5 (Celeste, et al, Proc. Natl. Acad. Sci. USA, 87:9843-9847, 1990), Drosophila 60A (Wharton, et al, Proc. Natl Acad. Sci. USA, 88:9214-9218, 1991), human BMP-2 and 4 (Wozney, et al, Science.242:1528-1534, 1988), Drosophila DPP (Padgett, et al, Nature, 325:81-84. 1987), human BMP-3 (Wozney, et al, Science, 242:1528-1534, 1988), human MIS (Cate, et al, Cell, 45:685-698, 1986), human inhibin , βA, and βB (Mason, et al, Biochem, Biophys. Res. Commun., 135:957-964. 1986), human TGF-β 1 (Derynck, et al, Nature, 316:701-705, 1985), humanTGF-β2 (deMartin, et al, EMBO J., 6:3673-3677, 1987), human TGF-β3 (ten Dijke, et al, Proc. Natl. Acad. Sci. USA, 85:4715-4719, 1988), chicken TGF-β4 (Jakowlew, et al, Mol Endocrinol, 2:1186-1195, 1988), and Xenopus TGF-β5 (Kondaiah, et al, J. Biol Chem., 265:1089-1093, 1990). The conserved cysteine residues are shaded. Dashes denote gaps introduced in order to maximize the alignment. Figure 4 shows the amino acid homologies among the different members ofthe TGF-β superfamily. Numbers represent percent amino acid identities between each pair calculated from the first conserved cysteine to the C-terminus. Boxes represent homologies among highly-related members within particular subgroups. The degree of sequence identify with known family members ranges from a minimum of 21% with MIS to a maximum of 34% with BMP-4. Hence, GDF-9 is comparable to MIS in its degree of sequence divergence from the other members of this superfamily. Moreover, GDF-9 shows no significant sequence homology to other family members in the pro-region ofthe molecule. GDF-9 also differs from the known family members in its pattern of cysteine residues in the C-terminal region. GDF-9 lacks the fourth cysteine ofthe seven cysteines that are present in all other family members; in place of cysteine at this position, the GDF-9 sequence contains a serine residue. In addition, GDF-9 does not contain a seventh cysteine residue elsewhere in the C-terminal region. EXAMPLE 3 IMMUNOCHEMICAL LOCALIZATION OF GDF-9 IN THE ZONA PELLUCIDA To determine whether GDF-9 mRNA was translated, sections of adult ovaries were incubated with antibodies directed against recombinant GDF-9 protein. In order to raise antibodies against GDF-9, portions of GDF-9 cDNA spanning amino acids 30 to 295 (pro-region) or 308 to 441 (mature region) were cloned into the T7-based pET3 expression vector (provided by F.W. Studier, Brookhaven National Laboratory), and te resulting plasmids were transformed into the BL21 (DE3) bacterial strain. Total cell extracts from isopropyl B -D-thiogalactoside-induced cells were electrophoresed on SDS/polyacrylamide gels, and the GDF-9 protein fragments were excised, mixed with Freund's adjuvant, and used to immunize rabbits by standard methods known to those of skill in the art. All immunizations were carried out by Spring Valley Lab (Sykesville, MD). The presence of GDF-9 reactive antibodies in the sera of these rabbits were assessed by Western analysis of bacterially-expressed protein by Western analysis. For immunohistochemical studies, ovaries were removed from adult mice, fixed in 4%> paraformaldehyde, embedded in paraffin, and sectioned. Sites of antibody binding were detected by using the Vectastain ABC kit, according to the instructions provided by Vector Laboratories. FIGURE 5 shows the immunohistochemical localization of GDF-9 protein. Adjacent sections of an adult ovary were either stained with hematoxylin and eosin (FIGURE 5 a) or incubated with immune (FIGURE 5b) or pre-immune (FIGURE 5c) serum at a dilution of 1:500. As show in FIGURE 5b, the antiserum detected protein solely in oocytes. No staining was detected using pre-immune serum (FIGURE 5c). Hence, GDF-9 protein appears to translated in vivo by oocytes. EXAMPLE 4 ISOLATION OF HUMAN GDF-9 In order to isolate a cDNA clone encoding human GDF-9, a cDNA library was constructed in lambda ZAP JT usign poly A-selected RNA prepared from an adult human ovary. From this library, a cDNA clone containing the entire human GDF-9 coding sequence was identified using standard screening techniques as in Example 1 and using the murine GDF-9 clone as a probe. A comparison of the predicted amino acid sequences of murine (top lines) and human (bottom lines) GDF-9 is shown in FIGURE 6. Numbers represent amino acid positions relative to the N-termini. Vertical lines represent sequence identities. Dots represent gaps introduced in order to maximize the alignment. The clear box shows the predicted proteolytic processing sites. The shaded boxes show the cysteine residues in the mature region ofthe proteins. The bars at the bottom show a schematic ofthe pre-(clear) and mature (shaded) regions of GDF-9 with the percent sequence identities between the murine and human sequences shown below. Like murine GDF-9, human GDF-9 contains a hydrophobic leader sequence, a putative RXXR proteolytic cleavage site, and a C-terminal region containing the hallmarks of other TGF-β family members. Murine and human GDF-9 are 64%> identical in the pro- region and 90%) identical in the predicted mature region ofthe molecule. The high degree of homology between the two sequences suggest that human GDF-9 plays an important role during embryonic development and/or in the adult ovary. EXAMPLE 5 NUCLEIC ACID DETECTION OF EXPRESSION OF GDF-9 IN OOCYTES In order to localize the expression of GDF-9 in the ovary, in situ hybridization to mouse ovary sections was carried out using an antisense GDF-9 RNA probe. FIGURE 7 shows in situ hybridization to adult ovary sections using a GDF-9 RNA probe. [ 35 S]-labeled anti-sense (FIGURE 7a and 7c) or sense (FIGURE 7b and 7d) GDF-9 RNA probes were hybridized to adjacent paraffin-embedded sections of ovarians fixed in 4% paraformaldehyde. Sections were dipped in photographic emulsion, exposed, developed, and then stained with hematoxylin and eosin. Two representative fields are shown. As shown in FIGURES 7a and 7c, GDF-9 mRNA was detected primarily in oocytes in adult ovaries. Every oocyte (regardless ofthe stage of follicular development) examined showed GDF-9 expression, and no expression was detected in any other cell types. No hybridization was seen using a control GDF-9 sense RNA probe (FIGURE 7b and 7d). Hence, GDF-9 expression appears to be oocyte-specific in adult ovaries. To determine the pattern of expression of GDF-9 mRNA during ovarian development, sections of neonatal ovaries were probed with a GDF-9 RNA probe. FIGURE 8 shows in situ hybridization to a postnatal day 4 ovary section using an antisense GDF-9 RNA probe. Sections were prepared as described for FIGURE 7. Following autoradiography and staining, the section was photographed under bright-field (FIGURE 8 a) or dark-field (FIGURE 8b) illumination. FIGURE 9 shows in situ hybridization to postnatal day 8 ovary sections using an antisense (FIGURE 9a) or sense (FIGURE 9b) GDF-9 RNA probe. Sections were prepared as described for FIGURE 7. GDF-9 mRNA expression was first detected at the onset of follicular development. This was most clearly evident at postnatal day 4, where only oocytes that were present in follicles showed GDF-9 expression (FIGURE 8): no expression was seen in oocytes that were not surrounded by granulosa cells. By postnatal day 8, every oocyte appeared to have undergone follicular development, and every oocyte showed GDF-9 expression (FIGURE 9). To determine whether GDF-9 was also expressed following ovulation, sections of mouse oviducts were examined by in situ hybridization. FIGURE 10 shows in situ hybridization to adult oviduct sections using an antisense (FIGURE 10a) or sense (FIGURE 10b) GDF-9 RNA probe. Sections were prepared as described for FIGURE 7. FIGURE 11 shows in situ hybridization to adult oviduct (0.5 days following fertilization) secction using an antisense GDF-9 RNA probe. Sections were prepared as described for FIGURE 7. Following autoradiography and staining, the section was photographed under bright-field (FIGURE 11 a) or dark-field (FIGURE 11 b) illumination. As shown in FIGURE 10, GDF-9 was expressed by oocytes that had been released into the oviduct. However, the expression of GDF-9 mRNA turned off rapidly following fertilization ofthe oocytes; by day 0.5 following fertilization, only some embryos (such as the one shown in FIGURE 11) expressed GDF-9 mRNA, and by day 1.5, all embryos were negative for GDF-9 expression. EXAMPLE 6 CONTRACEPTIVE TARGET GDF-9 is a novel protein growth factor which regulates the early development and the maturation of the egg (oocyte). Experimental results demonstrate that this factor is essential to the development ofthe egg. Several lines of evidence support this including: 1) GDF-9 mRNA is expressed exclusively by developing and maturing oocytes; 2) GDF- 9 protein is secreted by maturing oocytes and is essential for the normal development of the follicle; and 3) GDF-9 deficient (knockout) female mice do not develop mature eggs or follicles and are completely sterile (Dong et al, Nature, 383.531. 1996). GDF-9 is a highly specific and novel target for the development of a female contraceptive or as a nonsurgical method of sterilization. There are several different approaches one may use to develop a contraceptive using GDF-9 as a target: 1) the use of the GDF-9 protein or a peptide fragment as a "vaccine"; 2) use of an anti-GDF-9 antibody which binds to and effectively inhibit or neutralize the biological actions ofthe GDF-9 molecule; and 3) the use of a GDF-9 receptor antagonist. The term "vaccine" as used herein refers to a composition or compound that induces a protective immune response. For example, a GDF-9 "vaccine" protects agains conception or pregnancy and acts as a contraceptive. The following are examples includes different ways that oocyte development and maturation may be regulated in order to prevent ovulation or to cause permanent, nonsurgical sterilization in humans and in other species. These examples are intended to illustrate but not limit the invention. While they are typical of those that might be used, other procedures known to those skilled in the art may alternatively be used. 1. Active Immunization: GDF-9 "vaccines" The intact GDF-9 protein, or a fragment thereof, is an effective source ofthe composition used to induce an immune response directed toward oocytes (e.g., vaccine). The intact GDF-9 protein or a monomeric subunit can be economically produced in mammalian cell culture, yeast or microbial culture (such as Bacillus or E. coli). Alternatively, a peptide fragment of GDF-9 is also a suitable source for producing a vaccine. Typically, such fragments are 10 to 30 amino acids long, are exposed on the exterior portions of the GDF-9 molecule, and may be located within or near the receptor binding portion ofthe GDF-9 molecule. Several methods can be used to enhance the antigenicity of the GDF-9, or a fragment thereof. Such methods are well known and include forming a chemical complex between a hapten (GDF-9 or a fragment thereof) and a larger carrier molecule (hapten-carrier); mixing the antigen with an adjuvant; or denaturing the protein with heat, detergent, or chaotrophic agent (urea or guanidine-HCl). The following experiment can be performed to demonstrate that a GDF-9 composition is an effective contraceptive. Using New Zealand white rabbits as a model, the rabbits are immunized with either the intact GDF-9, a GDF-9 monomer, or one ofthe GDF-9 fragments listed in the table below. The route of administration is subcutaneous when an adjuvant is used. In the case when an adjuvant is not used, the routes of administration may include subcutaneous, intramuscular, intravenous or intraperitoneal. The preferred route is subcutaneous. Typically, single or multiple immunization may be required to produce an immune response to GDF-9. The humoral immune response may be monitored by routine serologic methods. Briefly, one to two weeks following the first immunization, a serum sample is obtained and the antibody titer to the GDF-9 protein is determined by either ELISA or RIA methods. A second or third immunization may be required every 10-14 days in order to produce an effective immune response. Table 1 GDF-9 vaccines, proteins, concentrations and formulations Vaccine Protein concentration Formulation (mg) Intact GDF-9 homodimer 0.1, 1.0, 10 neutral buffered saline solution with or without adjuvant 1 Heat denatured or chemically 0.1, 1.0, 10 neutral buffered saline denatured GDF-9 solution with or without adjuvant GDF-9 monomer 0.1, 1.0, 10 neutral buffered saline solution with or without adjuvant GDF-9 monomer conjugated 0.1, 1.0, 10 neutral buffered saline 0 to carrier protein 2 solution with or without adjuvant GDF-9 fragments 1 , 2 or 3 0.1, 1.0, 10 neutral buffered saline (predicted exposed site solution with adjuvant within putative receptor binding domain) 5 GDF-9 fragments 1 , 2 or 3 0.1 , 1.0, 10 neutral buffered saline conjugated to a carrier solution with or without protein adjuvant 'Adjuvants suitable for use in animals include Freunds complete or incomplete adjuvant. Adjuvants suitable for use in humans will be known to those of skill in the art. 2 Monomer is covalently coupled to a suitable carrier protein such as heat denatured immunoglobulin, denatured albumin or KLH. Rabbits are a good model to demonstrate the effectiveness of a GDF-9 vaccine. Rabbits are immunized with GDF-9 or a GDF-9 fragment in an adjuvant. Antibody titers to GDF-9 are determined in order to assure that a humoral response has been achieved. Gonadotrophin is administered in order to induce ovulation in the rabbit. Following gonadotrophin administration serum progesterone levels are measured. Low serum progesterone levels are an indication that ovulation is inhibited by hyperimmunizing the rabbits with GDF-9 vaccines. Histologic evaluation ofthe ovaries from GDF-9 vaccinated rabbits will show that the ovaries are intact. A mild mixed focal inflammatory infiltrate within the medulla of each ovary is observed. The ovaries will be devoid of mature oocytes and follicles. The cortex will appear normal. Histologic examination ofthe fallopian tubes and uterus will reveal no abnormalities or inflammation. 2. Passive Immunization Passive immunization is a second approach to developing a GDF-9 specific contraceptive. Using this approach, antibodies are produced which have high affinity of GDF-9. The antibodies are purified by conventional affinity chromatography methods (e.g., protein- A). In this instance, either a immunoglobulin enriched serum fraction (gamma globulin) or a monoclonal antibody generated against GDF-9 is suitable. In these instances, the anti-GDF-9 gamma globulin or the monoclonal antibody will have the property of specifically binding to GDF-9. The antibody may either block the binding ofthe GDF-9 to its natural receptor or function to increase the rate of clearance of the GDF-9 from the ovary. In either case, the objective is to allow the antibody to contact the GDF-9 produced by the oocytes and prevent it from contacting its natural receptor. For use in humans, the preferred antibody is a humanized monoclonal antibody. Production of murine monoclonal antibodies is well established and familiar to those skilled in the art. Briefly, mice are immunized with GDF-9 homodimer, monomer or a fragment (Table 1). Once a humoral response is produced, the spleen or lymph node cells are removed and fused with a mouse myeloma cell, typically SP2/0 or P-2 cells. The fused cells (hybridoma) are cultured in a selection media, cloned and subcloned to generate an immortal cell line producing an antibody to GDF-9. Due to its immunogenicity, the murine monoclonal antibody is not most desirable to use as a therapeutic for human use. The antigenicity of a murine antibody can be reduced by replacing the murine immunoglobulin heavy and light chain constant domains with the equivalent human antibody domains (chimeric antibody). The chimeric antibody can be further "humanized" by replacing intervening structural murine sequences within the antibodies hypervariable regions. This is referred to as a "fully humanized" antibody. The fully humanized antibody is preferred since this antibody can be used repeatedly in a human subject without causing an immune response to the antibody. 3. GDF-9 Receptor Antagonist A third approach to suppressing GDF-9 function is to develop a receptor antagonist. The approach is to first identify cell surface receptor(s) which are responsible for signal transduction in the ovary. These receptors are likely to be expressed on the egg or associated accessory cells (e.g., granulosa or thecal). Once a target cell population is identified, a receptor binding assay is used to identify peptides or small organic compounds which will bind to the GDF-9 receptor and prevent the GDF-9 from binding to its receptor. The use ofthe receptor antagonist has the advantage of being a specific inhibitor of GDF-9 induction of oocyte maturation and the potential to be a long-term, reversible therapeutic. Although the invention has been described with reference to the presently preferred embodiment, it should be understood that various modifications can be made without departing from the spirit ofthe invention. Accordingly, the invention is limited only by the following claims. SUMMARY OF SEQUENCES Sequence ID No. 1 is the nucleotide sequence for the primer, SJL160, for GDF-9 (page 24, lines 15 and 16); Sequence ID No. 2 is the nucleotide sequence for the primer, SJL153, for GDF-9 (page 24, lines 17 and 18); Sequence ID No. 3 is the nucleotide and deduced amino acid sequence for GDF-9 (Figure 2); Sequence ID No. 4 is the deduced amino acid sequence for GDF-9 (Figure 2); Sequence ID No. 5 is the amino acid sequence ofthe C-terminus of GDF-3 (Figure 3); Sequence ID No. 6 is the amino acid sequence ofthe C-terminus of GDF-9 (Figure 3); Sequence ID No. 7 is the amino acid sequence ofthe C-terminus of GDF-1 (Figure 3); Sequence ID No. 8 is the amino acid sequence ofthe C-terminus of Vg-1 (Figure 3); Sequence ID No. 9 is the amino acid sequence ofthe C-terminus of Vgr-1 (Figure 3); Sequence ID No. 10 is the amino acid sequence ofthe C-terminus of OP-1 (Figure 3); Sequence ID No. 11 is the amino acid sequence ofthe C-terminus of BMP-5 (Figure 3); Sequence ID No. 12 is the amino acid sequence ofthe C-terminus of 60A (Figure 3); Sequence ID No. 13 is the amino acid sequence ofthe C-terminus of BMP-2 (Figure 3); Sequence ID No. 14 is the amino acid sequence ofthe C-terminus of BMP-4 (Figure 3); Sequence ID No. 15 is the amino acid sequence ofthe C-terminus of DPP (Figure 3); Sequence ID No. 16 is the amino acid sequence ofthe C-terminus of BMP-3 (Figure 3); Sequence ID No. 17 is the amino acid sequence ofthe C-terminus of MIS (Figure 3); Sequence ID No. 18 is the amino acid sequence ofthe C-terminus of inhibin (Figure 3); Sequence ID No. 19 is the amino acid sequence ofthe C-terminus of βA (Figure 3); Sequence ID No. 20 is the amino acid sequence ofthe C-terminus of βB (Figure 3); Sequence ID No. 21 is the amino acid sequence ofthe C-terminus of TGF-β 1 (Figure 3); Sequence ID No.22 is the amino acid sequence ofthe C-terminus of TGF-β2 (Figure 3); Sequence ID No.23 is the amino acid sequence of the C-terminus of TGF-β3 (Figure 3); Sequence ID No. 24 is the amino acid sequence ofthe C-terminus of TGF-β4 (Figure 3); Sequence ID No.25 is the amino acid sequence ofthe C-terminus of TGF-β5 (Figure 3); and Sequence ID No. 26 is the amino acid sequence ofthe C-terminus of GDF-9 (Figure 6).

Claims: CLAIMS 1. A method for inhibiting oocyte maturation comprising contacting oocytes with an inhibiting effective amount of an inhibitor of GDF-9, thereby inhibiting oocyte maturation as compared to untreated oocytes. 2. The method of claim 1, wherein the inhibitor is a GDF-9 antibody or fragment thereof. 3. The method of claim 2, wherein the antibody is a monoclonal antibody. 4. The method of claim 3, wherein the antibody is a humanized antibody. 5. The method of claim 2, wherein the antibody is administered to a subject in vivo. 6. The method of claim 2, wherein the antibody is administered in a dose range of about 0.1 ug to 100 mg. 7. The method of claim 1 , wherein the inhibitor is a GDF-9 antisense molecule. 8. A method for inducing an immune response in a subject to GDF-9 whereby oocyte maturation is inhibited, comprising administering to a subject GDF-9 polypeptide or immunogenic fragment thereof and inducing an anti-GDF-9 immune response in the subject. 9. The method of claim 8, wherein the GDF-9 polypeptide or fragment thereof is administered with an adjuvant. 10. The method of claim 8, wherein the GDF-9 polypeptide or fragment thereof is administered by injection or by implantation in a slow release delivery vehicle. 11. The method of claim 8, wherein the GDF-9 polypeptide or fragment thereof is administered in a dose range of about 0.1 ug to 100 mg.

Inventors: LEE SE-JIN, LEE, SE-JIN
Applicants: UNIV JOHNS HOPKINS MED, THE JOHNS HOPKINS UNIVERSITY SCHOOL OF MEDICINE
Application year: 1998
Main classification: A61K38
IPC codes: A61K9, A61K31, A61K38, A61K39, A61K45, A61P15, A61P43, C07K14