Transfer of Resistance with Syphilitic Immune Cells: Lack of Correlation with Mitogenic Activity

Hamsters infected intradermally with Treponema pallidum Bosnia A develop extensive chronic skin lesions, usually accompanied by metastatic lesions involving the paws, lips, and anal region and by lymph nodes teeming with treponemes. Throughout the course of syphilitic infection, cells from the inguinal lymph nodes responded poorly to stimulation with suboptimal, optimal, or supraoptimal concentrations of concanavalin A, phytohemagglutinin P, or lipopolysaccharide. The response of syphilitic spleen cells was variable. Depression of lymphocyte reactivity to mitogens preceded clinical signs of infection and correlated well with the chronicity of syphilitic infection. When syphilitic hamsters were treated with a curative dose of penicillin, their mitogenic responses returned to normal or were slightly elevated. No correlation existed between mitogenic activity and the ability of lymphoid cells to induce an effective immune response when transferred to normal recipients. No significant differences in protection were detected among recipients of immune cells with or without activity to mitogens. These results demonstrate that lymphocyte transformation by mitogens in vitro is not a measure of effective treponemicidal activity and so may not be a valid indicator of the protective immune status of syphilitic animals.