H-2 hierarchy in the IR-gene controlled responses to hapten-modified mouse serum albumin.

Five hapten-modified autogenous mouse serum albumins (MSA), TNP11MSA, FITC8MSA, DNP64MSA, DNP5MSA, and PC2MSA, were tested for their ability to induce hapten-specific antibody responses in H-2 congenic mice of the H2d, H-2b, H-2a, and H-2f haplotypes. Four of the five modified MSAs, TNP11MSA, FITC8MSA, DNP64MSA, and PC2MSA, stimulated responses found to be under H-2-linked Ir gene control, whereas DNP5MSA failed to induce responses in any strain tested. H-2d, H-2D, and H-2a mice responded to FITC8MSA; H-2d and H-2b responded to TNP11MSA; and only H-2d mice were high responders to DNP64MSA and PC2MSA. H-2f mice failed to respond to any of the stimulating antigens. Thus, a hierarchy of H-2 haplotypes was observed in the responsiveness to modified MSA with H-2d greater than H-2b greater than H-2a greater than H-2f. Primed lymph node cells from PC2MSA immunized H-2d mice were challenged with antigen in vitro to assess the nature of the determinant recognized by T cells in the response to modified MSA. Lymph node cells proliferated only when challenged with PC2MSA. Unmodified MSA or TNP11MSA did not stimulate a proliferative response, suggesting that the immune T cells recognize a neodeterminant present on the modified PC2MSA.