Bovine trichomoniasis as a model for development of vaccines against sexually-transmitted disease

PROBLEM: Human sexually transmitted diseases (STDs) are widespread but effe ctive vaccines are rare. Experimental and commercially available vaccines f or bovine trichomoniasis have been well studied. Principles for immune prot ection of the female genital tract derived from studies of bovine trichomon iasis may be generally applicable to human trichomoniasis and other STDs. METHOD OF STUDY: A bovine model of trichomoniasis has been developed for st udy of mechanisms of immunoprophylaxis. RESULTS: Both systemic and local immunization with an immunoaffinity purifi ed antigen cleared the genital tract of trichomonads significantly earlier than non-immunized controls. Predominantly IgA responses or predominantly I gG responses in uterine and vaginal secretions were essentially equally pro tective. Uterine and vaginal IgA. responses could be induced by systemic pr iming and local boosting via either the vaginal or nasal mucosa. In either case, lymphoid aggregates were formed in the uterine and vaginal mucosa whi ch were not present in the genital mucosa of naive animals. CONCLUSIONS: Systemic immunization or systemic priming with local boosting protects against bovine trichomoniasis via IgG or IgA antibodies (respectiv ely) to a major surface antigen of trichomonads. Immunization of the genita l mucosa results in formation of inductive sites for a local IgA response.