EXTRACTION OF SP18 FAMILY MEMBRANE-PROTEINS ON POSTERIOR HEAD OF BULLSPERM AND THE EFFECT OF ANTI-SP18 IGG ON SPERM MOTILITY AND MURINE IN-VITRO FERTILIZATION

Bovine sperm heads were separated via ultrasonic treatment and centrif ugation. Anti-bull sperm IgG was produced by immunizing rabbits with a crosome-reacted bull sperm heads. SDS PAGE patterns revealed that the main membrane proteins on acrosome-reacted bull sperm head were sp18 f amily, including 18, 16, and 14 kD, which represented about 64% of the total membrane proteins in bull sperm. Indirect immunofluorescence sh own sp18 antigens primarily distributed in postacrosomal and proximal tail regions. Western blot analysis revealed that the anti-bull sperm IgG reacted with sp18 antigens in acrosome-reacted bull sperm head and bull seminal plasma. Anti-bull sperm IgG also reacted with 14, 16, 18 , 42, 57 and 60 kD proteins in fresh bull, mouse and rabbit sperm. Ant i-sp18 IgG caused agglutination of bull and rabbit sperm, but had no e ffect on murine sperm. In murine in vitro fertilization trials, preinc ubating capacitated sperm with 0.364 mg/ml of anti-sp18 IgG resulted i n a decrease in the fertilization rate from 75.6% in the controls to 5 0.8% in the experimental groups (p<0.001).