Abstract
Normal human sera have been shown to kill murine target cells, including both normal lymphoid and tumoral cells. In this study, the evidence of activation of complement system for this heterocytotoxicity is presented. Chemical carcinogen-induced EL4 lymphoma cells were used as target cells. The EL4 cells were obtained either from the ascitic fluid of tumorous mice or from tissue culture. The cytotoxicity of human serum was determined by microscopic examination of viability of target cells after incubation with serum samples. Viable cells were determined by exclusion of trypan blue dye. The hemolytic activity of serum complement was quantitated by microtiter plate assay with EA cells.
The evidence for the activation of complement system responsible for the heterocytotoxicity of human serum to EL4 cell was obtained from decomplementary experiments. 1) Both the cytotoxic effect and hemolytic activity of human serum was totally abolished after heating at 56°C for 30 min.
