Genetic definition of a further gene region and identification of at least three different histocompatibility genes in the rat major histocompatibility system

Abstract

Two new recombinant haplotypes of the rat major histocompatibility system, RT1, have been detected in [LEW.1A (RT1a) x LEW.1W (RT1U)] x LEW.1N(RT1n) segregating hybrids. Recombinant r3 carries the RT1.A region (determining classical transplantation antigens) and the RT1.B region (determining strong mixed lymphocyte reactivity and genetic control of antipolypeptide immune responsiveness) of the RT1a parent, bur rejects RT1a skin grafts. Recombinant r4 carries the A and B regions of the RT1u parent, but rejects RT1u skin grafts. The two histocompatibility genes detected are allelic to each other. The relevant locus, designated as H-C, maps to the B-region side of the RT1 system and appears to mark a third RT1 gene region, RT1.C. Availability of haplotypes r3 and r4 allowed the definition of a histocompatibility locus in the B region, H-B. The products of H-C, H-B and of the previously described H-A gene vary in antigenic strength.

Genetic control of rat heart allograft rejection: effect of different MHC and non-MHC incompatibilities

“…Among the RT1 regions, differences at the RT1.B/D region were the strongest stimuli for heart allograft rejection. This result is in accordance with data obtained with kidney (Paris and GiJnther 1980), pancreas (Klempnauer et al 1983a), and skin (Kohoutov~i et al 1980) transplants in the same set of strains. Rapid rejection across a class II barrier was also observed in RT1 congenic strains on the PVG genetic background after heart (Guttmann et al 1985, Rozing et al 1983) and liver (Tsuchimoto et al 1985) transplantation.…”

“…It could be argued that the genetic background of the various congenic strains used is not completely histocompatible. In the course of complementation studies, however, no evidence for histoincompatibility due to the genetic background genes among the congenic strains has been obtained (Kohoutov~i et al 1980 and our own unpublished data). Furthermore, it might be brought forward that the definition of the recombinants as to the exact position of the recombination event is still too imprecise.…”

“…1R3 and LEW.1R4, carry the class III genes of RTI" origin. From complementation tests (Kohoutov~i et al 1980) it can be concluded, however, that the class III region does not contain histocompatibility genes, which induce skin graft rejection. It has recently turned out that DP-like class II genes map to the RT1.A side of the RT1.B/D region (Wurst et al 1988, W. Wurst and E. Gtinther, unpublished data).…”

Comparison of Antigens in the Rat MHC That Act as CML Determinants

“…and RTI.A is quite low. In the CT system, no recombinants have been identified in 170 animals tested [18], and the re combination frequency between RTI.E and RTI.A is 1/250 [7], By contrast, the frequency of recombina tion between RTI.A and RT1.Cis much higher, since 2 recombinants have been identified in 68 animals tested [6]. Second, the tissue distribution of the RT1.C and RT1.EU antigens are different: RT1.C antigens are not found on red blood cells or on liver cells [20], whereas RTI.E1 1 is found on both erythrocytes [9] and liver cells [ 10].…”

Comparative genomic aspects of rat, mouse and human MHC class I gene regions

“…1), was first described on the basis of RT1 recombinants (Kohoutova et al, 1980), and then characterized by histogenetic, serological and molecular genetic analysis. The PAC contigs reveal the complex organization of this region (Fig.…”