Effect of serum lymphocytotoxic activity on T and B cells in rabbits infected with Treponema pallidum.

The correlation between the level of cold autolymphocytotoxic activity in the sera of rabbits infected with T. pallidum, and the percentage of B and T cells in the peripheral blood of the same animals was determined. The percentage of cells was estimated by the E and EAC rosette techniques and by the immunofluorescence test on immunoglobulin-bearing (B) cells. It was found that the increase of the autolymphocytotoxic activity was connected with the proportional decrease of B lymphocytes and increase of T lymphocytes. Since the decrease of B cells was significant (p less than 0.05) it is suggested that the autolymphocytotoxic activity may be involved in killing of B lymphocytes also in vivo. The possible role of the complement-dependent autolymphocytotoxic serum activity in regulation of humoral response in syphilis is discussed.