The response of young chronically protein-deficient mice to multiple antigenic challenge.

Responses to two or more antigens given together or separated by an interval of up to four days were determined in young mice maintained from weaning on a 4% albumin diet, and compared with those of normally-fed controls. Simultaneous challenge with several antigens did not affect antibody production in mice of either dietary group ("Simultaneous Competition") and the responses of normal and protein-deficient mice to sheep or rat erythrocytes were similarly produced by the prior injection of horse or sheep cells ("Sequential Competition"). However, the low protein diet broadened the conditions under which primary and secondary injections of diphtheria toxoid impaired primary responses to tetanus toxoid. These findings are discussed in relation to mechanisms previously proposed to explain antigenic competition, with a view to explaining the effects of protein-deficiency on antibody production.