Effect of splenectomy on treatment of Lewis lung carcinoma by an immunomodulatory polysaccharide and a cytotoxic agent.

The effect of the spleen on the efficiency of chemotherapy (cyclophosphamide) and immunotherapy (the polysaccharide levan) of C57BL mice bearing the Lewis lung carcinoma was studied. The development of Lewis lung carcinoma caused a gradual splenomegaly in the C57BL mice. Splenectomy did not, however, affect tumor growth in the nontreated host. Levan induced a pronounced splenomegaly. Splenectomy reduced markedly the antitumoral effect of the polysaccharide. These results indicate that spleen elements participate in the inhibitory activity of levan. By contrast, splenectomy had no effect on the efficiency of treatment of cyclophosphamide.