CONTINUED MANNING OF CHROMOSOME-2 GENES

This report describes our continued efforts to elucidate the genetic f ine structure of the central portion of the mouse chromosome (Chr) 2. Mice from our panel of 28 Chr 2 congenic strains were tested: 1) for t he presence of the antigens which stimulate Chr 2-reactive lymphocyte clones in mixed lymphocyte reaction (MLR); 2) for the antigens of hist ocompatibility (H) genes H-42(a) and H-45(a) as determined by allograf t rejection; and 3) for their ability to respond to the H-Y antigen in a cell-mediated lysis assay. The results obtained in this study have allowed additional mapping of immunologically involved Chr 2 genes. Th e gene encoding the antigen which stimulates lymphocyte clone 1C11 can be considered wholly different from other Chr 2 H genes on the basis of chromosomal recombination. We have assigned the symbol H-48 to this gene. The following gene order has been established: [H-3, B2m, pa], we, [H-42, H-48,] H-45, IR-H-Y, Hd-1, un, H-13, A(w). The order of the bracketed genes is not known. H-44 maps centromeric to IR-H-Y. The ge nes encoding the antigens that stimulate lymphocyte clones 2G7, 2C10, 1F6, 1B10, and 1H10 map centromeric to H45.