Characterization of Antibodies Generated Against a Conserved Portion of Oviductal Glycoprotein (OGP) and Endogenous Hamster OGP and Their Ability to Decrease Sperm Binding to the Zona Pellucida In Vitro

PROBLEM: The effect of antibodies generated against hamster oviductal glycoprotein (OGP) on sperm binding to the zona pellucida (ZP) was evaluated. METHOD OF STUDY: Antibodies against a 17‐amino‐acid sequence of the OGP core protein (amino acids 52–68) and the denatured hamster OGP protein were generated, characterized, and tested in an in vitro sperm binding assay. RESULTS: Sperm binding was significantly decreased (P < 0.05) when oviductal oocytes were incubated for 2 hr with 4 or 8 mg/ml of immune IgG of both antibodies when compared with normal rabbit IgG. A fluorescence assay showed binding of both antibodies to the endogenous OGP associated with the ZP of ovulated hamster oocytes. CONCLUSIONS: These results suggest that OGP may be a potential immunocontraceptive target because both antibodies significantly decreased sperm binding to the ZP of oviductal oocytes. Immunocontraception may be accomplished by attempting to generate active immunity to a recombinant OGP, to the region selected in this study (amino acids 52–68) or to some other region of the core protein.