| Abstract: | Cynomolgus monkeys (Macaca fascicularis) were immunized with porcine zonae pellucidae to assess the possible antifertility effects of the zona antibodies. Serum antibody titers were evaluated utilizing a rapid solid-phase radioimmunoassay. Six of twelve monkeys conceived 6 to 10 wk after vaccination. All monkeys reached maximal antiserum titers by the time of conception, although the six animals that did not conceive had considerably lower antibody titers. Further pregnancies did not occur until antibody level had declined markedly, 8 mo after last immunization. The menses of all but one of the remaining six monkeys were interrupted intermittently. Also, the usual midcycle elevated estradiol levels were absent for several cycles. Both menses and midcycle estradiol peaks were reestablished in all but one monkey 3 to 5 mo after the last booster was given. Two monkeys conceived when serum antibody levels dropped to one fourth of maximal, but both had a still birth. Histological observations showed accumulation of luteal tissue and massive atresia of small follicles at the end of the study (18 mo). We conclude that through heteroimmunization with porcine zona pellucida monkeys can become infertile and that this condition is reversible. Because the zona preparation used in this study appeared to contain traces of nonzona material, it was not possible to determine whether the menstrual irregularities and oocyte atresia that we observed were owing to immunological effects on the zona itself or to the production of antibodies against other ovarian components. |
