Fertilization of Antiserum-Inhibited Frog Eggs with "Capacitated" Sperm

Fertilization of the frog egg requires the presence of jelly material which is deposited on the egg during its passage through the oviduct. This requirement takes the form of jelly-induced changes in sperm which have been compared to capacitation of mammalian sperm. "Uncapacitated" frog sperm becomes "capacitated" after being in contact with jelly and presumably occurs in normal fertilization during the passage of sperm through the jelly. Fertilization of jelly-coated eggs is inhibited by pretreatment of eggs with antisera prepared against the jelly. This inhibition of fertilization by the antibody is attributed to blocking of specific jelly-receptor sites which are essential for interaction with sperm. Uterine eggs pretreated with anti-jelly serum may be compared to jellyless eggs in that no jelly components are available for interaction with the sperm. Results are presented which demonstrate that "capacitated" sperm are capable of fertilizing eggs which have their jelly-receptor sites neutralized by anti-jelly serum.