On the immunogenicity of the beta subunit of ovine luteinizing hormone (oLH beta) and equine chorionic gonadotropin (eCG) in the chimpanzee (Pan troglodytes): effect of antiserum on monkey cycle and early pregnancy.

Antibody to ovine LH beta (oLH beta) subunit and equine chorionic gonadotropin (eCG) were produced in adult male chimpanzees and evaluated for cross reactivity with oLH, human chorionic gonadotropin (hCG) and eCG by in vitro and in vivo methods. Chimpanzee antiserum to eCG failed to cross-react with hCG, but antibody raised against oLH beta subunit effectively neutralized not only exogenously administered hCG but also endogenous pituitary LH and monkey (Macaca radiata) chorionic gonadotropin. Chimpanzee antiserum to oLH beta when administered early in pregnancy reduced progesterone levels and terminated gestation in bonnet monkeys. Our data suggest that active immunization of chimpanzee, an ape that is very close to human, with oLH beta subunit leads to production of antibodies that are likely to affect both normal cycle as well as pregnancy.