Syphilis Vaccine and Immune Mechanisms.

Although complete immunity can be accomplished in rabbits by immunizing intravenously with 60 injections of freshly isolated, gamma-irradiated T. pallidum over a 37 week period, no significant protection was achieved when the gamma-irradiated treponemes were preserved in liquid nitrogen and used as immunizing agents, with or without an alginate-gluconate adjuvant, in a practical injection and time schedule vaccinated animals produced both VDRL and FTA-ABS antibodies, but not TPI antibody.