Molecular basis of sperm-egg interaction and the prospects for immunocontraception

As the molecular basis of sperm-egg interaction is resolved, so new opportu nities are created for the development of immunological approaches to disru pt the process of conception. Thus, realisation that the zona glycoprotein, ZP3, serves as a specific receptor for spermatozoa, has prompted a detaile d examination of its contraceptive potential. In primate models, recombinan t ZP3 has been shown to suppress fertility very efficiently, however this e fficacy is tempered by the appearance of adverse side-effects involving acc elerated primordial follicle depletion and a lymphocytic infiltration of th e ovarian stroma. Synthetic peptides encoding B-cell epitopes have been fou nd to circumvent the lymphocyte response although the effectiveness of such reagents in preventing the loss of primordial follicles has not yet been d etermined. The induction of active immunity against sperm-specific antigens has also been shown to generate long term infertility in both males and fe males. Molecular and immunological techniques are now being used to produce a rapidly expanding list of unique sperm antigens which are currently bein g evaluated to determine their potential contribution to the development of safe, effective, contraceptive vaccines. (C) 1998 Published by Elsevier Sc ience Ireland Ltd. All rights reserved.