Current Status of Mammalian Zona Pellucida Glycoprotein as Immunocontraceptive Vaccine

Antibodies directed against the zona pellucida can interrupt sperm-egg recognition in vitro. However, the mechanisms by which anti-zona antibodies exert this contraceptive effect in vivo remain uncertain. There is an accumulating body of evidence to suggest that active immunity against zona antigens not only induces infertility via an antibody-mediated interruption of sperm—egg interaction but also disrupts normal ovarian function. Thus, ZP glycoprotein based immunocontraceptive vaccines offer an attractive proposition for controlling wild life population. To make it a practical proposition for human use, additional investigations are required to optimise and devise novel strategies for effective immunocontraceptive vaccine. Observed ovarian dysfunction in animals, often associated with immunisation by ZP glycoproteins is one of the major stumbling blocks for their use in humans. Appropriate B cell epitopes of ZP glycoproteins that are devoid of oophoritogenic T-cell epitopes which may inhibit fertility without concomitant oophoritis, may be critical to determine their feasibility for human use.