Comparative in vitro sensitivity of twom methylcholanthrene-induced murine sarcoma lines to humoral and cellular immune cytotoxicity.

MC57M and G are the tissue-culture derivatives of two methylcholanthrene-induced murine C57Bl sarcomas. Their sensitivity to immune cytoxic3, cytostatic or cytolytic spleen cells and sera was compared in parallel in vitro assays. The level of cross-reactivity displayed by the two lines was found to depend on the nature of the immune effector rather than on the assay which was used. It was high with immune spleen lymphocytes, alone or in the presence of decomplemented antisera, and low with antisera in the presence of rabbit complement. MC57G cells were more sensitive than MC57M cells to both effectors. Both cell lines were insensitive to antibody-dependent cell-mediated cytotoxicity. Preliminary evidence is presented, suggesting a probable involvement of embryonic and Moloney leukemia virus-induced cell surface antigens in the vitro sensitization of the two tumor lines to immune sera.