Effect of route of infection with Treponema pallidum. In vitro cellular response to treponemal antigens.

We investigated how route of infection with Treponema pallidum affects cellular responses of various lymphoid tissues. Lymphoid cells from spleens and lymph nodes of rabbits infected intradermally with T pallidum showed enhanced in vitro responses to treponemal antigens when cultured in autologous rabbit serum. Intravenous infection with T pallidum increased the responsiveness of splenic lymphocytes to T pallidum antigen only during the time of lesion development; lymph node lymphocytes responded throughout the first 30 days of infection, whereas peripheral blood lymphocytes did not respond to treponemal antigens in vitro. Lymphocytes from spleens and peripheral blood of intratesticularly infected rabbits poorly to T pallidum when cultured in autologous serum, but not when cultured in normal serum; however, lymph node lymphocytes from the same rabbits responded normally to T pallidum antigen in either type of serum.