VACCINES FOR BACTERIAL SEXUALLY-TRANSMITTED INFECTIONS - A REALISTIC GOAL

Bacterial infections of the genital tract (gonorrhea, chlamydia, chanc roid, syphilis) are common and cause significant morbidity. Their impo rtance is heightened by recent appreciation of their roles in facilita tion of transmission of the human immunodeficiency virus (HIV). Each i s capable of causing repeated infections, suggesting lack of permanent broadly effective immunity. An effective vaccine has yet to be develo ped for any of these diseases. Rapid progress in understanding the mol ecular basis for pathogenesis of infection, including mechanisms for e scape from otherwise effective immune surveillance and mechanisms for causing injury to host cells, has stimulated renewed efforts to make v accines for some of these infections. Progress has been greatest for N eisseria gonorrhoeae and Chlamydia trachomatis. Present emphasis is on the major or principal outer membrane proteins of N. gonorrhoeae and C. trachomatis. based on evidence for neutralizing antibodies directed against surface-exposed variable domains of each of these proteins. O ther surface-exposed proteins, including the iron-repressible transfer rin receptor in gonococci and certain heat-shock proteins in chlamydia , also may be targets for vaccines. Although much remains to be learne d, cautious optimism is warranted.