Loss of Fertilizing Power of Sea-Urchin and Urechis Sperm Treated with “Univalent” Antibodies vs. Antifertilizin. ∗

Summary

Antisera were produced in rabbits by immunization with purified anti-fertilizin of Lytechinus and of Urechis and were photo-oxidized so as to convert the antibodies into the “univalent” (non-agglutinating) form. Sperm treated with such antisera were found to possess less than 1/64 of the fertilizing capacity of the controls although their activity was not noticeably affected. The bearing of the results on the significance of antifertilizin in the fertilization reaction is briefly discussed and the possible general use of “univalent” antibodies is mentioned.