IMPAIRED FERTILITY IN FEMALE RATS IMMUNIZED WITH SYNTHETIC PEPTIDE SEGMENTS OF 2 SPERM PROTEINS

Female rats were immunized with two synthetic peptide segments conjuga ted to tetanus toroid (TT), and designated as YAL-198-TT and rSMP-230- TT. The peptide segments correspond to the N terminal region of the sp erm proteins designated as YWK-II and rSMP. After completion of the im munization, the females were mated with proven fertile male rats. Amon g the immunized females, 38 and 45%, respectively, were infertile. Ser um progesterone levels of the immunized infertile animals on day 6 of the expected pregnancy were similar to that of controls, and were sign ificantly lower on day 14 of the expected pregnancy. The present findi ngs suggest that antisperm antibodies induce infertility by blocking b lastocysts implantation and/or by having cytotoxic effect on developin g embryos.