Immunity to chemically induced rat sarcomas: study of the specificity of cytotoxic cells.

Spleen cells from WAG rats bearing methylcholanthrene-induced sarcomas were cytotoxic for homologous tumour cells and for some cell lines derived from other syngeneic tumours. Each tumour induced its own pattern of cross-reactive cytotoxicity. This cross-reactivity was not apparent by in vivo rejection tests. In tumour-bearing rats, specific cytotoxic cells could not be separated from cross-reactive cytotoxic cells. The effector cells did not adhere to plastic surface, they were retained neither on nylon wool nor on anti-Ig columns and were devoid of Fc receptors. After tumour excision the cells displaying specific cytotoxicity had the same properties and thus were probably T cells. In contrast, the cells exhibiting cross-reactive cytotoxicity were lost after passage through a nylon wool column or after the removal of Fc-receptor-bearing lymphocytes. These findings suggest that cross-reactivity could result from antibody-dependent cell-mediate cytotoxicity directed against shared antigens.