RESUMO
Conservative sperm acrosomal antigens that react with a monoclonal sperm antibody against human spermatozoa HS63 were purified by immunoaffinity chromatography from rabbit testes. The purity and the molecular weight of the purified antigens were determined by SDS acrylamide gel electrophoresis. There is only a band on the acrylamide gel. The molecular weight is more than 60000. It is found that the antigen is a glycoprotein with the carbohydrate moiety of 17%. Following successive immunization antisera of high titers were raised and shown to react specifically with antigens on sperm acrosome, but not with any somatic cells as judged. By using mouse in vitro fertilization experiments and sperm penetration assay with zona-free hamster ova, the isoimmune sera from rabbit exhibited high degrees of fertilization inhibition as compared to the control sera. The results suggest that sperm-specific antigen reactive to HS63 may be a good candidates for the development of immunocontraceptive vaccines in humans.