Studies on autolymphocytotoxic activity occurring in Treponema pallidum infection.

It was found that in sera of majority of syphilitic rabbits cold lymphocytotoxic activity occurs. This activity appears usually 3 to 10 weeks after infection and it is present for 9 to 10 weeks. Lymphocytotoxic activity was found in undiluted sera or diluted from 1/2 to 1/8. This activity was directed against B lymphocytes only. Lymphocytotoxicity was found only in sera with high level of VDRL antibodies. The role of this activity in syphilis is not known. The killing effect exerted on B lymphocytes producing syphilitic reagins directed not only against T. pallidum, suggests that lymphocytotoxic activity may take part in the regulation of humoral response at the beginning of syphilitic infection.