CML typing of serologically identicalH-2 mutants

Abstract

Cell-mediated lympholysis (CML) reactions were studied among four strains of C57BL/6 (B6) mice carrying mutant alleles (H-2ba,H-2bd,H-2bg, andH-2bh) at thez1 locus in theK end ofH-2b and the original B6 (H-2b) strain. Cross killing of target cells from lines that had not participated in the mixed lymphocyte reaction (MLR) was extensive, but usually less intense than that of target cells of stimulator cell genotype. The extent of CML crossreactivity could be limited by using cells from F1 hybrid mice as responders in MLR. In a comprehensive analysis of the cytotoxicity exerted by 20 MLR combinations with homozygous, and 10 MLR combinations with F1 hybrid responder cells, 19 different CML cytotoxicity patterns were identified, corresponding to at least 19 different CML target specificites. When the number of CML mismatches of each mutant with the originalH-2b was calculated,H-2ba was found to be most distinct fromH-2b,H-2bs andH-2bd were closest toH-2b, andH-2bh occupied an intermediate position. The validity of this sequence of relatedness is supported by published reports on skin graft survival times and on the interaction of T lymphocytes with virus-infected target cells using cells fromz1 locus mutants.