ANTIGENIC COMPETITION BETWEEN POLYPEPTIDYL DETERMINANTS IN NORMAL AND TOLERANT RABBITS

Abstract

Competition between two polypeptidyl determinants was studied in normal rabbits and rabbits made tolerant to the competing antigen. The capacity of poly-DL-phenylalanyl protein conjugate to inhibit the formation of antibodies specific to the poly-DL-alanyl determinant was dependent on the nature of the protein carrier of the singly substituted antigens. Competition occurred only when the peptidyl determinants were attached to identical or similar (RSA and HSA) carriers. Thus, the immune response toward the poly-DL-alanyl determinant was impaired by injecting the pairs p-DL-PheRSA and p-DL-AlaHSA, or p-DL-PheRNase and p-DL-AlaRNase. Suppression of the formation of antibodies with poly-DL-alanyl specificity was not observed, however, upon administration of p-DL-PheRSA together with p-DL-AlaRNase or of p-DL-PheRNase with p-DL-AlaHSA.