Abstract
A resistance locus to leukemogenesis in mice by A-RadLV (a variant of the radiation leukemia virus) is described. This locus, Rrv-1, was mapped to subregions I-A, I-B, and I-J of the H-2 complex. It is suggested that Rrv-1 may be in complementation with a second locus to the right of it, between Rrv-1 and H-2D. This localization and the complementation of the two loci for resistance are characteristics similar to Ir genes, and indicate a possible relationship between the genetic regulation of immune responsiveness and susceptibility to leukemia.