Antifertility effects of human sperm antigen in female rats

The sperm antigens responsible for inducing infertility were identified by Western blot technique using sera from an infertile woman with circulating antisperm antibodies. The 80 Kda was prepared from human sperm by extraction with 0.05% sodium deoxycholate in 0.01 M Tris-HCl buffer, pH 8.4 and fractionation with ammonium sulphate. The supernatant after 40% saturation ammonium sulphate extraction was separated by gelpermeation chromatography, using HPLC (Protein PAK 125 column) and FPLC (superose 12 column) systems. The homogeneity of the protein was established by SDS-PAGE and its molecular size was estimated to be 80 Kda and its isoelectric point was 4.5. The purified protein upon active immunization in female rats caused infertility in 100 percent animals. The data suggest that 80 Kda human sperm antigen has the potential for use as a contraceptive vaccine.