Mouse mast cells as anti-tumor effector cells

Mast cells were obtained in a high state of purity from mouse peritoneal washings by means of centrifugation over metrizamide density gradients. In microcytotoxicity assays in vitro they were cytotoxic to cells of a mouse methylcholanthrene-induced fibrosarcoma (C-4). Mast cells from uninjected mice, mice injected intraperitoneally with proteose peptone, and C-4-bearing mice were equally effective. They were also cytotoxic to two rat fibrosarcomas and, to a much lesser extent, to mouse fibroblasts. Cytotoxicity was inhibited by cAMP, DBcAMP, and reserpine but not by chloroquin, hydrocortisone, chlorpheniramine, promethazine, cimetidine, sodium cromoglycate, protamine sulfate, cytochalasin B, or colchicine.