Status of contraceptive vaccines

Abstract

Problem: This is a review of anti-sperm contraceptive vaccines (CV), and synthesis of human scFv antibodies that can be used as immunocontraceptives.

Method of study: Various methods of proteomics and genomics, peptide synthesis, phage display technology, and antibody engineering were used to obtain multi-epitope vaccines and human scFv antibodies from immunoinfertile and vasectomized men. The present review primarily focuses on the effect of multi-epitope vaccines and Izumo on fertility, and synthesis and characterization of sperm specific human scFv antibodies.

Results: The immunization with Izumo peptides causes a contraceptive effect in female mice. The efficacy is enhanced by combination vaccination, including peptides based on other sperm antigens. Using phage display technology, we were able to synthesize at least four novel scFv antibodies with unique complementarity determining regions (CDRs) that reacted with specific fertility-related sperm antigens. These antibodies inhibited human sperm function in vitro, and their immunocontraceptive effect in vivo by these antibodies is currently being investigated.

Conclusion: The multi-epitope vaccines may provide an efficacious and viable approach to contraception. The human scFv antibodies, if they block fertility in vivo, may provide unique and novel immunocontraceptives, the first of its kind for human use. The multi-epitope CV and preformed engineered antibodies of defined specificity may obliterate the concern related to inter-individual variability of the immune response.