Prevention of monkey sperm penetration of zona-free hamster ova by sperm antibody obtained from vasectomized cynomolgus monkeys.

Incubation of antisperm sera from vasectomized cynomolgus monkeys (Macaca fascicularis) with monkey sperm caused a fourfold reduction of sperm attachment to and penetration of zona-free Golden hamster ova. The attachment of sperm to hamster ova was reduced from 64% to 11%, and the penetration of ova was reduced from 20% to 5%. Sperm antibodies block sperm attachment to the vitelline membrane, thus preventing ovum penetration. This blockage may be one of the reasons for low fertility rates observed following reanastomosis of the vas deferens in those vasectomized males that show high levels of circulating antisperm antibody.