Polymorphism of the DR1 Haplotype: Structural and Functional Analysis.

摘要

HLA-DR haplotypes vary in the number of Dw subtypes defined by the mixed lymphocyte reaction (MLR). DR2 and DR4 have been shown to be quite complex where as DR1 is relatively homogeneous in populations of Northern European extraction. In Caucasians, almost all DR1 individuals express a DR1, DQw5, Dw1 haplotype. The DR1 haplotype in American blacks is always associated with DQw5, but approximately 50% of DR1 positive American blacks express a Dw allele undefined by mixed lymphocyte typing. It is not clear whether the DR1, Dw- haplotype found in American blacks, which is not associated with HLA-B14, is the same variant described by others. The structure and function of the American black DR1, DQw5, Dw- haplotype have been studied and compared to the Caucasian DR1 haplotype using alloproliferative T-cell clones and cDNA sequencing. Six alloproliferative T-cell clones, primed against a Caucasian DR1 haplotype, have been tested with a panel of 204 stimulator cells including 21 DR1 positive cells from both blacks and Caucasians. The variability observed with the MLR can be paralleled by alloproliferative T-cell clone reactivity. In addition, failure to observe a complete correlation with the Dw typing response suggests that the T-cell clones detect additional variability within the DR1 haplotypes. Keywords: Human lymphocyte antigens; Reprints. (KT)