Lymphocytotoxicity of chickens bearing Rous sarcomas.

A 51Cr uptake microcytotoxicity assay was used to determine the cytotoxicity of lymphocytes from chickens bearing Rous sarcomas. Differences in lymphocyte cytotoxicity among individual chickens were statistically significant. Lymphocytes from chickens regressing (or having regressed) their tumors were significantly more cytotoxic than lymphocytes from hosts with progressing tumors. Lymphocytes from chickens with progressing tumors tended to enhance tumor cell growth in vitro.