ANTISERA THAT BLOCK CELL DIVISION IN DEVELOPING EGGS OF SEA URCHINS

Abstract
Cell division in developing sea-urchin eggs can be blocked by rabbit antisera against homologous fertilizin (the surface coat of the unfertilized egg) and, somewhat less effectively, by antisera against other extracts of the eggs and embryos at various stages of development. Anti-sera against sperm are ineffective in this regard as are also antisera against blood and epidermal tissue of the adult. Cross-reaction occurs with related species of sea urchins. Inactivation of complement does not reduce the blocking action of the antisera. Upon dilution of the fertilizin-antisera, development is blocked at progressively later stages of development.