CHARACTERIZATION OF IMMUNOSUPPRESSIVE ACTIVITY OF ADRIAMYCIN AND DAUNOMYCIN ON HUMORAL ANTIBODY-PRODUCTION AND TUMOR ALLOGRAFT-REJECTION

Abstract

The effects of adriamycin (AM) and its analog daunomycin (DM) on immunological responsiveness in L1210 leukemia were investigated in an effort to elucidate whether a differential interaction of the 2 drugs with the immune system could paly role in the higher antineoplastic activity of AM. AM induced a greater reduction in the number of antibody-producing cells after primary stimulation with sheep erythrocytes but DM was more suppressive on the secondary response to the same antigen. Primary reactivity to the T (tumor)-independent antigen S-lll was reduced by AM and DM was ineffective in the same conditions even at high doses. In addition, when a tumor allograft model was investigated, DM was significantly more immunosuppressive than was AM administered at equitoxic doses in mice. In contrast, these agents displayed similar activity in reducing bone marrow stem cells and in inhibiting DNA synthesis in this organ. The possibility that the different immunosuppressive capacity of AM and DM contributes to the greater antitumoral activity of the former is advanced.