Delayed-type hypersensitivity to allogeneic cells in mice. III. Sensitivity to cell-surface antigens coded by the major histocompatibility complex and by other genes.

DTH could be induced to cell-surface antigens coded by either H-2 or non-H-2 genes. Sensitivity was more readily induced across I region than across K- or D-region differences. The presence of an I-region difference during sensitization did not significantly increase the DTH response to K- or D-region-coded antigens. Macrophage processing appeared to be the major route of sensitization to background antigens. Thus, high levels of sensitivity were achieved equally well using viable or disrupted cells, the response was independent of the H-2 haplotype of the allogeneic cells, and transfer was restricted to the K end of the host H-2 complex. Although sensitization to H-2 antigens was obtained with disrupted cells, transfer of sensitivity against viable cells was unrestricted. This suggests a minor role for macrophage processing in sensitization to H-2 antigens.