Exploitation of sperm-Escherichia coli interaction at the receptor-ligand level for the development of anti-receptor antibodies as the vaginal contraceptive.

Abstract

In an earlier work performed in our laboratory, we have been able to isolate a sperm receptor (SR) from human spermatozoa playing critical role in fertilization using sperm--E. coli interactions at the receptor-ligand level. It has been hypothesized that for the development of an immunocontraceptive, antibodies generated against the SR should have the ability to impair sperm parameters. In this league, an attempt was made to generate anti-SR antibodies and their effect on sperm parameters such as motility, viability, Mg(2+) -dependent ATPase activity, acrosome status, and apoptotic index was examined. Loss of sperm motility was observed with 100% agglutination. Interaction of anti-SR antibodies with spermatozoa resulted in reduced Mg(2+) -dependent ATPase activity (1020 ± 0.53%), premature acrosomal loss (61.5 ± 0.67%) as well as induced apoptosis (58.76 ± 2.5%). The induction of sperm damage was specifically because of anti-SR polyclonal antibodies as it could be mitigated by the addition of purified SR. Further, when in vivo efficacy of anti-SR antibodies was checked, results showed that a single intravaginal administration with anti-SR antibodies in female BALB/c mice led to the failure of conception. However, simultaneous administration of SR with anti-SR polyclonal antibodies resulted in sustenance of fertility. Infertility induced by anti-SR antibodies did not show any other tissue pathology; hence the present work highlights the potential of anti-SR polyclonal antibodies to be used as a vaginal contraceptive.