Extraction of sp18 family membrane proteins on posterior head of bull sperm and the effect of anti-sp18 IgG on sperm motility and murine in vitro fertilization.

摘要

Cattle sperm heads were separated via ultrasonic treatment and centrifugation. Anti-bull sperm IgG was produced by immunizing rabbits with acrosome-reacted bull sperm heads. SDS-PAGE patterns revealed that the main membrane proteins on acrosome-reacted bull sperm head were sp18 family, including 18, 16 and 14 kDa proteins, which represented about 64% of the total membrane proteins in bull spermatozoa. Indirect immunofluorescence showed that sp18 antigens were primarily distributed in the postacrosomal and proximal tail regions. Western blot analysis revealed that the anti-bull sperm IgG reacted with sp18 antigens in acrosome-reacted bull sperm heads and bull seminal plasma. Anti-bull sperm IgG also reacted with 14, 16, 18, 42, 57 and 60 kDa proteins in fresh bull, mouse and rabbit spermatozoa. Anti-sp18 IgG caused agglutination of bull and rabbit spermatozoa, but had no effect on mouse spermatozoa. In mouse in vitro fertilization trials, preincubating capacitated spermatozoa with 0.364 mg/ml of anti-sp18 IgG resulted in a decrease in the fertilization rate from 75.6% in the controls to 50.8% in the experimental groups (P<0.001).