Antibody-dependent cytolysis of Trypanosoma cruzi by human polymorphonuclear leukocytes.

Human polymorphonuclear leukocytes were cytotoxic to Trypanosoma cruzi epimastigotes in the presence of specific antibodies from Chagas' disease patients and sera from rabbits immunized with homogenates of T. cruzi epimastigotes. Cytotoxicity was evaluated by the in vitro release of [³H]uridine-labeled RNA from culture forms. Under the same conditions, mononuclear cells were not cytotoxic. Pretreatment of target cells with antibodies was as effective as the continued presence of antisera during the reaction, while sera-treated effector cells did not mediate cytotoxicity. The cytotoxic effect depended on the concentration of effector cells and antibody and was progressive until 4 hr of incubation at 28 °C.