At Least Two Loci of the Major Histocompatibility Complex Can Determine Mixed Lymphocyte Stimulation in the Rat

Abstract

Analysis of a recombinant haplotype of the major histocompatibility complex showed that two genetically separable loci (or groups of loci), LD--1 and LD--2, determine mixed lymphocyte stimulation in the rat. LD--1 maps into the H--1B region which contains the Ir genes and is associated with strong, mixed lymphocyte stimulation. LD--2 maps into the H--1A region and determines weak stimulation. LD--1 and LD--2 determinants can be detected by primed lymphocyte typing.

Close association between particular I region‐determined cell surface antigens and Ir gene‐controlled immune responsiveness to synthetic polypeptides in wild rats

“…The weak MLR stimulation which was sometimes observed between (T, G)-A--L responder and H -l a lymphocytes or (H,G)-A--L HR and H-1' lymphocytes can most easily be explained by residual incompatibility for minor, H-1 A regiondetermined MLR antigens [9]. It is, however, not excluded that slight variants of H -l a or H-1' major MLR antigens occurred in wild rats.…”

“…The major MLR locus of the rat maps into the H-1B gene region where Ia and Ir genes are localized, whereas the H-1 A region, which is mainly defined by determining the classical transplantation antigens, codes for minor MLR antigens [9]. In order to decide whether high anti-(T, G)-A--L responsiveness was indeed associated with the H-1 B region-determined MHC antigens, primed lymphocyte typing was carried out with responder cells that were selectively primed against H-1 B"determined antigens (LEW.l AR 1 (H-larl) anti-LEW.1A (H-1") lymphocytes).…”

“…Recom-binant H-1 haplotypes [7, 81 allow the distinction of two H-1 gene regions. The H-1 A region determines the classical transplantation antigens [7,81 and minor MLR antigens [9]. The H-1B region contains Ir genes [8], Ia genes [7, 81 and major MLR genes and is homologous to the H-21 region of the mouse.…”

Mixed lymphocyte reactivity in cattle

“…The results did suggest that MLR is controlled by one genetic system and this idea is consistent with results in other species. Generally, strong responses are raised by mismatching at one locus whereas weaker responses are raised against antigens of another locus, which is also MHC linked (Bijnen et al 1977, Goldman et al 1975, Gunther & Stark 1978, Widmer & Balner 1978. The exception to this is the cow where the existence of two strong MLR-controlling loci has been postulated (Usinger et al 1977).…”