Specificity and genetic restrictions of the guinea-pig immune response to dinitrophenyl-lysyl-alanyl octapeptides.

A series of 2,4-dinitrophenyl (DNP) octapeptides containing L-lysine and L-alanine were prepared to examine the specificity and genetic restrictions of both cellular and humoral immune responses in inbred guinea-pigs. Strains 2 and 13 guinea-pigs were therefore immunized with Lys4-Ala3-Lys(DNP), Lys3Ala4-Lys(DNP), Lys2-Ala5-Lys(DNP) and Lys-Ala6-Lys(DNP). Only Lys4-Ala3-Lys(DNP) was under Ir gene control and could induce both antibody and T-cell responses in strain 2 guinea-pigs. In contrast, Lys4-Ala3-Lys(DNP) injected in strain 13 guinea-pigs and the other DNP-octapeptides injected in strain 2 or 13 guinea-pigs elicited only antibody formation and no specific T-cell mediated response. Antibody formed in the absence of specific T-cell responsiveness in either strain 2 or 13 was hapten specific and lacked the capacity to discriminate the immunizing antigen from closely related DNP-peptides. Antibody produced by animals with specific T-cell responses, on the other hand, was exquisitely specific for the immunizing peptide and could discriminate it from closely related peptides.