Immunity to lymphoid tumors in syngeneic mice by immunization with mitomycin C-treated cells.

Immunization of mice with syngeneic mitomycin C-treated lymphoid tumor cells (EL-4 and S49A) conferred a high degree of immunity to transplantation with viable tumor cells in syngeneic animals. The development of this immunity was paralleled by the development of specific cell-mediated cytotoxicity; no anti-tumor antibodies could be detected in the immunized animals. In contrast to the high immunoprophylactic capacity of mitomycin C-treated cells, attempts to utilize these cells for immunotherapy were unsuccessful. Preliminary experiments did not reveal antigenic differences between mitomycin C-treated and untreated tumor cells.