Characterizations of anti-oLH beta antibodies acting as contraceptives in rhesus monkeys. II. In vivo neutralizing ability for gonadotropic hormones.
63 female rhesus monkeys were actively immunized against the beta-subunit of ovine luteinizing hormone (oLH beta). 75% of these monkeys developed antibodies which were sufficiently high to induce infertility. We report here the in vivo neutralizing potencies of anti-oLH beta antisera from 14 monkeys and the correlation between in vitro and in vivo properties of the antibodies. Anti-oLH beta sera neutralized the biological activity (stimulation of testosterone production in male mice) of both hCG and rhCG. The correlation between antibody titers and neutralizing potency of hCG action of the antisera was significant. rhCG-induced testosterone production was inhibited more effectively than that induced by hCG. There was no correlation between binding affinity to hCG in vitro and neutralizing activity. Neutralizing activities correlated well with binding capacities, suggesting that the number of binding sites of the antibody population may play an important role in the mechanism of neutralization. In rhesus monkeys that were effectively immunized against pregnancy circulating oLH beta antisera did induce shortened luteal phases and impaired luteal function. Successful application of oLH beta as an antigen for contraception in humans may depend on relative cross-reactions of hLH and hCG with anti-oLH beta sera and on a neutralizing capability very similar to the one found in rhesus monkeys.
D000818:Animals; D000906:Antibodies / Q000032:analysis; D006063:Chorionic Gonadotropin / Q000037:antagonists & inhibitors; D003267:Contraception / Q000379:methods*; D003269:Contraception, Immunologic / Q000379:methods*; D005260:Female; D006062:Gonadotropins / Q000037:antagonists & inhibitors*; D007106:Immune Sera / Q000494:pharmacology; D007114:Immunization; D007986:Luteinizing Hormone / Q000276:immunology*; D008253:Macaca mulatta; D010446:Peptide Fragments / Q000276:immunology*
D000906:Antibodies; D006063:Chorionic Gonadotropin; D006062:Gonadotropins; D007106:Immune Sera; D010446:Peptide Fragments; D007986:Luteinizing Hormone