Dermal histocompatibility and in vitro lymphocyte reactions of three newH-2 mutants

Histocompatibility of skin grafts and in vitro lymphocyte reactions of three new H-2 mutants (B6-H-2 ^bg1, B6-H-2 ^bg2, and B6-H-2 ^bh ) are described. Complementation tests indicated thatH-2 ^bg1,H-2 ^bg2, andH-2 ^bh were mutations at the same locus (z-1) and allelic withH-2 ^ba . Two of the lines, B6-H-2 ^bg1 and B6-H-2 ^bg2, appeared identical, although they were of spontaneous and independent origin. The third line, B6-H-2 ^bh , was unique. Such graft rejection was paralleled by reactivity in the MLR and by the generation of cytotoxic lymphocytes in vitro. The pattern of crossreactivity among antigens specified by these mutant genes supports the notion that thez-1 locus controls multiple specificities. The results indicate that a single point mutation can simultaneously affect histocompatibility, MLR, and CML reactions.The genetic nomenclature for theH-2 complex is that of Kleinet al. (1974a).