Allograft rejection-defined antigens of the B2m,H-3 region

In this report we delineate the production and histocompatibility characteristics of two new B2m, H-3 region congenic strains, B10.SM-a and B10.FS-a, and further characterize previously described strains. Strains C57BL/10 and B10-we are shown to be histocompatible by the exchange of skin grafts, as are strains B10.UW-we,un at, B10.UW we un a, B10.UW-we + a, B10.UW-+ + a and B10.LP-a. (The latter group will be called B10-H-3b when referred to collectively). C57BL/10, B10-H-3b, B10.C-a, B10.KR-a, B10-pa at, B10.SM-a, and B10.FS-a are shown to be histoincompatible by the rejection of exchanged skin grafts, and histoincompatibility between these strains has been localized to the B2m, H-3 region. The histoincompatibility between C57BL/10 and B10.FS-a is of particular significance because of the identity of these strains at the B2m, H-3 region loci B2m and H-3. Thus the B2m, H-3 region histoincompatibility herein described defines a new locus, which we have called H-42, the a allele being assigned to C57BL/10 and the b allele to B10.FS-a. By using cross-immunization techniques, four allograft rejection-defined reactivity patterns (ADR) have been defined that show concordant strain distribution patterns with the CTL-defined reactivity patterns described elsewhere. On the basis of data presented in this report indicating C57BL/10 and B10.FS-a to differ by a histocompatibility gene in the B2m, H-3 region, and data presented by Kurtz et al. elsewhere indicating C57BL/10 and B10.FS-a to possess the same alleles at the B2m and H-3 loci, the presence of at least three B2m, H-3 region loci-defining cell membrane antigens is established.