Cell-mediated immune reactions as probes of sensitization to tumour-associated antigens of methylcholanthrene-induced mouse sarcomas.

The evaluation of the Field-Caspary macrophage electrophoretic mobility (MEM) assay as a probe of sensitization to tumour-associated antigens was performed in the genetically defined experimental system of methylcholanthrene-induced sarcomas in C57BL10/ScSnPh mice. Six sarcomas carrying noncross-reacting tumour-associated transplantation antigens were examined. For comparison, antigenic specificity of the six sarcomas was simultaneously assessed by the microcytotoxicity assay with 3H-thymidine. Immunization of mice with syngeneic tumour cells as well as sensitization of lymph node cells (LNC) in vitro lead to the generation of cytotoxic lymphocytes. Tumour bearers' LNC were not cytotoxic; when added to preimmunized LNC, the tumour bearers' LNC suppressed cytotoxicity. In contrast to the results obtained with the microcytotoxicity assay, the MEM test gave positive results with LNC from both tumour-bearing and tumour-immunized mice. Whereas some cross-reactions were observed among the fibrosarcomas in the microcytotoxicity assay (6 out of 28 combinations examined), the results of the Field-Caspary MEM test showed the same individually specific pattern of antigenicity as observed in transplantation tests and revealed no cross-reactivity in the 25 combinations tested.