H-2 effects on cell-cell interactions in the response to single non-H-2 alloantigens. V. Effects of H-2K^b mutations on presentation of H-4 and H-3 alloantigens

The effects of a panel of H-2K^b mutants on the presentation of the non-H-2 histocompatibility (H) antigens H-4.2 and H-3.1 to antigen-specific T cells were examined. K^b-restricted cytotoxic effector T cells were presented with H-4.2 ad H-3.1 in the context of mutant K^b alleles. H-4.2 was differentially presented by K^b mutants to K^b-restricted cytotoxic effectors. Cold target inhibition analysis demonstrated that K^b-restricted, H-4.2-specific cytotoxic effectors recognized H-4.2 in the context of at least three restriction sites on the K^b molecule. One site is specific for K^b alone, whereas two additional sites are differentially expressed by K^b mutant molecules. The effect of K^b mutations on the presentation of H-4.2 and H-3.1 was H antigen-specific. Identical, respective patterns of presentation of H-4.2 and H-3.1 by K^b mutants were observed with K^b-restricted T cells proliferating in secondary mixed lymphocyte culture. Further, individual mice varied in their preference for H-3.1 presented in the context of different K^b mutant molecules. These observations demonstrate that the presentation of H antigens by mutant K^b molecules is antigen-specific; analysis of presentation of H antigen by mutants to wild-type K^b-restricted effectors allows the identification of multiple restriction sites on the K^b molecules.