title: Microheterogeneity of HLA-DR4 haplotypes: DNA sequence analysis of LD"KT2" and LD"TAS" haplotypes.
abstract: We have isolated and sequenced cDNA clones corresponding to the polymorphic alpha and beta chains encoded by the DR and DQ subregions of two HLA-DR4 haplotypes, LD"KT2" and LD"TAS". These two haplotypes are distinguished on the basis of mixed lymphocyte culture typing. The data indicate that the designation of LD"TAS" as a distinct subtype from Dw13 is very likely due to amino acid differences in the DQ beta chain. In contrast, LD"KT2" differs from TAS and Dw13 by a single amino acid substitution at position 37 of the DR beta 1 chain. The functional and evolutionary significance of these polymorphisms is discussed.
mesh_terms: D000595:Amino Acid Sequence; D001402:B-Lymphocytes / Q000032:analysis; D001483:Base Sequence; D002460:Cell Line; D004247:DNA / Q000032:analysis; D006681:HLA-D Antigens / Q000235:genetics*; D006683:HLA-DQ Antigens / Q000235:genetics; D006684:HLA-DR Antigens / Q000235:genetics*; D015804:HLA-DR4 Antigen; D006801:Humans; D007959:Lymphocyte Culture Test, Mixed; D011110:Polymorphism, Genetic
chemical_list: D006681:HLA-D Antigens; D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens; D015804:HLA-DR4 Antigen; D004247:DNA