[Attempts at developing a syphilis vaccine (author's transl)].

Numerous investigators tried over the years to induce artifically immunity against syphilis by use of a variety of treponema preparations. None of these immunization experiments performed by different means and routes provided clear evidence of acquired immunity in animals and humans given various vaccine preparations against challenge with even minimal doses of virulent T. pallidum. In recent years, however, promising results have been obtained in the immunization study. Two types of syphilis vaccine have been developed which were found very effective in conferring a protection against syphilitic infection on rabbits: (1) the first vaccine contains T. pallidum attenuated by gamma irradiation, and the other one (2) contains T. pallidum killed by penicillin. In addition, it has been demonstrated that the immunogenic activity of T. pallidum is related to their very labile protein component. Pretty much is also known on the factors influencing the immune response of artificially immunized rabbits, and on the immunological mechanisms underlying the development of syphilis immunity.