Penetration of zona-free hamster eggs by boar sperm treated with the ionophore A23187 and inhibition of penetration by antiplasma membrane antibodies.

Uncapacitated boar sperm treated with the divalent cation ionophore A23187 in the presence of calcium bind to and penetrate zone-free hamster eggs. Penetration by ionophore-treated sperm is, however, blocked when sperm are pretreated with antisperm plasma membrane Fab. The antibody apparently interferes with the interaction of sperm surface antigens with the egg plasma membrane since the antibodies have no significant effect on the motility of sperm nor on the induction of the acrosome reaction by the ionophore. The assay described herein is useful for studying the role of sperm surface antigens in the penetration and fertilization of eggs.