Effects of Carrageenan and High Serum Dilution on Synergistic Cytotoxicity to Tumor Cells

Summary Neither the C1 inhibitor carrageenan nor extensive dilution of the test sera (to 1:2560) abolished the specific killing of tumor cells in the presence of nonsensitized lymphoid cells and sera from tumor-bearing mice (i.e., synergistic cytotoxicity). The two lines of evidence indicate that conventional complement-dependent cytotoxicity does not play a role in synergistic cytotoxicity to tumor cells.