Augmentation of the development of immune responses of mice against allogeneic tumor cells after adriamycin treatment.

In C57BL/6J mice, depending on the dose of P815 cells used for immunization, Adriamycin exerted different effects on the cell-mediated lytic response and complement-dependent cytotoxicity. At the dose of 3 X 10(7) P815 cells, Adriamycin treatment had no apparent effect on cell-mediated lytic response regardless of timing of drug treatment. At lower doses of antigen (10(7) or 5 X 10(6) cells), the response was augmented in Adriamycin-pretreated mice. Similarly, under conditions which led to a suboptimal complement-dependent humoral response of untreated control, Adriamycin pretreatment resulted in an augmented response; under conditions of maximal response, Adriamycin was suppressive. Suppression was maximal if the drug was injected at either the same time or shortly before or after antigen. The cell-mediated lytic response was proportional to the dose of antigen used, while the complement-dependent humoral lytic response was inversely proportional to dose of antigen in the range used in these experiments. Secondary cell-mediated lytic response in culture was also augmented if mice had been pretreated with Adriamycin 5 days before the primary immunization. The cell-mediated lytic response of spleen and peritoneal exudate cells from mice immunized with relatively low doses of P815 cells 5 days after treatment with Adriamycin was increased 12 to 15 days after immunization. The cytotoxic effects were present in both plastic adherent and nonadherent fractions of either spleen or peritoneal cell populations. All these effector cells were found to be anti-Thy 1.2 sensitive. The phagocytic activity of spleen cells was increased after immunization, but no drug effect was observed; following 24 hr of culture, however, cells from drug-treated immunized donors had increased phagocytic activity as compared to that of controls. Increased phagocytosis also developed in cells nonadherent to plastic.