CORTICAL RESPONSE ANTIGENS RELEASED AT FERTILIZATION FROM SEA URCHIN EGGS AND THEIR RELATION TO ANTIGENS OF THE JELLY COAT

¹ Institute of Molecular Evolution, University of Miami, Coral Gables, Florida 33134, and the Marine Biological Laboratory, Woods Hole, Massachusetts 02543

1. The supernatant sea water of inseminated dejellied or trypsin treated Arbacia punctulata eggs was shown to contain a sperm agglutinin which was released from the eggs after insemination. This sperm agglutinin has previously been called "cytofertilizin" in other species.

2. A sperm agglutinin was also released from dejellied eggs in which the formation of a fertilization membrane had been artificially induced.

3. Agglutination inhibition experiments suggested that the agglutinin released from dejellied fertilized eggs (cytofertilizin) and the agglutinin from egg jelly (fertilizin) bind to the same sperm receptor sites.

4. Egg jelly preparations were found to contain at least 4 antigenically distinct macromolecules. At least 1 of the egg jelly antigens was the sperm agglutinin, fertilizin.

5. On the basis of double diffusion studies using antiserum against egg jelly, the 4 antigens in egg jelly preparations were indistinguishable from 4 antigens released from dejellied eggs during the cortical response to fertilization (cortical response antigens).

6. At least 3 antigens were released from dejellied or trypsin treated unfertilized eggs. These antigens were also present in egg jelly preparations and cortical response antigen preparations, but did not induce sperm agglutination.

7. Double diffusion studies using antiserum against cortical response antigens indicated that at least 7 antigens were released from dejellied eggs when they were inseminated or when the formation of the fertilization membrane was artificially induced. The same antigens were released from trypsin treated eggs after insemination.

8. The significance of these findings is discussed in relation to cytofertilizin and the fertilization product. The results indicate that cytofertilizin and fertilizin are functionally and antigenically identical.