Soybean and ascorbate feeding in experimental carcinogenesis: immunological studies.

Soybean and/or sodium ascorbate have been demonstrated to have protective effects against carcinogenicity of the nitrosamine precursors dibutylamine and sodium nitrite in rats. Some immunological aspects of the cellular and humoral compartments of the immune system were investigated in this experimental model. The parameters chosen for the study were the lymphocyte transformation test, migration inhibition test, the demonstration of Fc and Fc plus complement receptors on the lymphocyte surface (EA and EAC rosette-forming test), and the determination of total serum proteins and their fractions. The results indicated that dibutylnitrosamine can be formed in vivo from its precursors dibutylamine and sodium nitrite, and that it affects the immune system of rats which showed an immunosuppressed state present as depressed cellular and humoral immunity. The protective role of soybean and/or ascorbate against carcinogenicity of dibutylamine and sodium nitrite was demonstrated by the absence of tumor formation. These agents were found to be capable of increasing the defense mechanism of rats by enhancing both cellular and humoral immunity in the presence of the carcinogenic nitrosamine precursors dibutylamine and sodium nitrite.