Cytokine enhancement of immune responses important for immunocontraception

To be effective, an immunocontraceptive vaccine should elicit strong, sustained antibody responses. Circulating antibodies may block the function of hormones and target some gamete antigens, but the most effective inhibition of fertilization will probably be achieved by antibodies in the reproductive tract. It may also be beneficial to administer vaccine antigens with strong adjuvants, such as cytokines, in order to achieve high specific antibody titres. In this review recent findings concerning the role of cytokines in the regulation of antibody responses, particularly at mucosae, are described and prospects for immunization for immune responses which may be important for fertility control are discussed. On the basis of these findings, a model system for the delivery of vaccine antigens to the immune system in vaccinia, fowlpox or DNA plasmid vectors along with type-2 cytokines, such as interleukin-4 (IL-4), IL-5 and IL-6, as B cell adjuvants is presented. Studies such as these in the areas of antigen delivery and enhancement of immune responses are aimed at providing new options for fertility control, particularly via oral vaccination.