Inhibition of Antibody Synthesis by L-Phenylalanine

Abstract

Antibody synthesis in response to the injection of diphtheria toxoid into rabbits and rats was used to study the effects of an excess of the amino acid L-phenylalanine on protein synthesis. Injections of phenylalanine produced a marked inhibition of antibody synthesis in both the rat and the rabbit. The dosage of phenylalanine used caused an increase over the normal concentration of phenylalanine in the plasma and spleen of rats, but did not cause a loss of weight or serum protein changes in the treated animals.