Abstract: | Female rabbits were wholly depleted of complement by treatment with anti-complementary cobra venom factor (CVF) 36 h before mating. Complement depletion did not compromise occurrence of the acrosome reaction, as judged by sperm penetration of eggs collected 12-13 h post coitum. However, in CVF-treated females, significantly more spermatozoa had penetrated the egg vestments, more spermatozoa were present in flushings from the oviducts, and sometimes the uterus, than in control females mated to the same males. The results indicate that, although the acrosome reaction is unlikely to depend on complement activation, complement-dependent factors may exert a restrictive effect on spermatozoa after vaginal insemination of the normal female rabbit. |