STUDIES ON TREPONEMA PALLIDUM AND SYPHILIS : II. SPIROCHAETICIDAL ANTIBODIES AGAINST TREPONEMA PALLIDUM.

We believe that our experiments have shown that the serum of rabbits and sheep immunized with cultures of Treponema pallidum acquires spirochaeticidal properties for these culture spirochaetes. The normal serum of these animals also possesses spirochaeticidal action if used in sufficient quantities, and the action of the immune serum represents probably an increase of the antibodies normally present. Both normal and immune spirochaeticidal properties are destroyed by heating to 56 degrees C. The spirochaeticidal action of the immune serum can be reactivated by the addition of fresh normal serum of the same species, insufficient in amount to exert a spirochaeticidal effect by itself. The structure of these spirochaeticidal bodies, therefore, is entirely analogous to that of the well known bactericidal antibodies known to exist in antibacterial sera. We do not wish to have these results interpreted as applying to virulent spirochaetes as well as to culture spirochaetes. A subsequent publication will demonstrate why we specify this at present.