Serological distinction of mutants B6.CH(zl) and B6.M505 from strain C57BL-6

A quantitative serological difference was found between strains Hz1 and M505 carrying mutant H-2 haplotypes ba and bd, respectively, and the original strain B6(H-2(b)). The finding suggests that the mutations occurred in the H-2K(b) gene, and together with data on MLR and CML challenges the current concept of H-2 regions' involvement in immune reactions.