Nutrition and tumor immunity: divergent effects of antitumor antibody.

Nutritional deficiency reduces antibody synthetic capacity. Antibody directed against tumor antigens, however, may serve either to heighten tumor immunity, as in antibody-dependent cellular cytotoxicity, or to diminish host resistance to cancer growth by "blocking" cell-mediated tumor immunity. Diets made deficient in specific amino acids are inimical to tumor growth, apparently through reduction of synthesis of blocking antibody. Thus, where tumor immune function is involved, complex and possibly paradoxical effects of nutritional status on tumor growth can be predicted.