Immunocontraceptive approaches in females

In the female reproductive system, there are multiple points, where immunointerception is feasible. Among these, the most promising are those that interfere immunologically at the level of sperm-egg interaction or neutralize human chorionic gonadotropin (hCG), which is required for the establishment and maintenance of pregnancy. Immunization studies in various animal models including non-human primates with zona pellucida (ZP) glycoproteins have demonstrated curtailment of fertility. To circumvent the ovarian pathology often observed following immunization with ZP glycoproteins, synthetic peptides devoid of 'oophoritogenic' T cell epitopes as immunogens have been proposed. Though of utility for controlling wildlife populations, its application in humans will have to wait till the safety of ZP glycoprotein vaccine is established beyond doubt. Clinical trials in women have established that immunocontraceptive vaccine based on Beta-subunit of hCG inhibits fertility. To make it a practical proposition, novel strategies have to be adopted to increase its immunogenicity so that 'contraceptive' antibody titers are achieved in near to 100% recipients.