Studies on antigenic competition.

Antigenic competition was studied in a haptenic system. It was found that: (a) The extent of competition is greater when larger doses of antigen are employed. (b) Antigenic competition appears to be independent of the carrier molecule. (c) The affinity of the antibody produced in antigenic competition is approximately equal to the affinity of antibody formed by animals immunized with only one antigen. (d) Antigenic competition only occurs when both antigens are injected so as to drain into the same regional lymph nodes. The results suggest that antigenic competition occurs locally at the site of antigen stimulation and is not mediated by a circulating factor, by tolerance induction, or by suppression due to synthesis of cross-reacting antibodies.