Passive immunization for immunocontraception: lessons learned from infectious diseases

Development of vaccine for contraception is an exciting proposition that could provide a valuable alternative to the presently available methods for birth control. Various targets such as gonadotropin releasing hormone (GnRH), follicle stimulating hormone (FSH), leutinizing hormone (LH), zona pellucida (ZP) antigens, sperm antigens, and human chorionic gonadotropin (hCG) are being explored for immunocontraception. Besides specific concerns associated with each contraceptive vaccine, the progress has been restricted by the variability of the immune response after active immunization, attain and maintain high antibody titers, time lag to achieve reasonably good antibody titers, and uncertainty regarding how long the bioeffective antibodies will remain in circulation. It is envisaged that these concerns may be taken care of by using the preformed antibodies in the passive immunization approach. The antibody therapies have been tried and found to be successful against various infectious diseases both in animals as well as humans. Some have become treatment modalities in the clinics. This manuscript will review the data available for the passive immunization of preformed polyclonal and murine/humanized/human monoclonal antibodies, their efficacy, mode of delivery, duration of the effects, and limitations, if any. The overall objective is to examine the feasibility and practicability of the passive immunization approach for immunocontraception.