Failure to detect cell-mediated cytotoxicity against Chlamydia trachomatis-infected cells.

Mice were infected with Chlamydia trachomatis (L2/434) and at various intervals after infection their lymphoid cells were tested directly for cytotoxic activity against Chlamydia-infected L929 cells. In a modified cell-mediated lympholysis assay, splenic, lymph node, and peritoneal exudate cells did not significantly cause the destruction of the infected targets, although infection did result in the formation of antichlamydial antibodies. Whereas chlamydial antigens are capable of activating cell-mediated immunity in other experimental models, our results show that either this chlamydial infection does not induce the generation of cytotoxic effector cells or chlamydial antigens are absent from the surface of infected cells.