H-2 antigens of certain t and non-t mice react with the same monoclonal antibody.

Monoclonal antibody 212.i.4.2 mediated complement-dependent lysis of spleen and lymph node cells carrying the tw1 , tw12 , tw71 , t6, tw73 , and tLub1 haplotypes, while cells from mice carrying 11 other t haplotypes were not lysed. The antibody also detected an epitope controlled by genes in the H-2Dd region of non-t mice. A molecule of 46,000 molecular weight was immunoprecipitated by 212.i.4.2 from detergent extracts of 125I-labelled spleen cells of +/ tw12 and B10.D2 mice. The H- 2dm2 mutation did not alter the expression of the epitope recognized by 212.i.4.2. However, the H- 2dm1 mutation decreased the reactivity of lymphoid cells with the antibody in cytotoxicity tests, and 212.i.4.2 immunoprecipitated little or no protein from extracts of B10.D2( R106 ) spleen cells which carry the H- 2dm1 mutation.