Lack of cell-mediated cytotoxicity towards Chlamydia trachomatis infected target cells in humans

Induction of cell-mediated cytotoxicity towards Chlamydia trachomatis infected target cells was studied in humans. PHA-derived lymphoblasts, infected with inactivated or virulent LGV-2 chlamydial particles, were used as target cells. Chlamydial primed T cell blasts or specific, cloned T cells were used as effector cells. A highly sensitive 18 hours lytic assay employing 111In-labelled target cells was used. Specific cytotoxicity towards C. trachomatis infected target cells in humans could not be detected. This was the case regardless of the origin of the effector cells or the various protocols tested. However, this assay was capable of yielding significant positive results with effector cells primed to alloantigens. We conclude that cell-mediated cytotoxicity towards bacterial infected target cells probably does not play a major role.