title: Sequence polymorphism of HLA DR beta 1 alleles relating to T-cell-recognized determinants.
abstract: HLA class II molecules are a highly polymorphic family of dimeric cell-surface proteins primarily involved in regulating T-cell responses to extrinsic antigens. To define regions of class II molecules involved in T-cell recognition, we have now compared sequences of three HLA DR beta cDNA clones obtained from cells that all express the same serologically defined determinants but differ in terms of T-cell-recognized specificities. The comparisons indicate that very few (one to four) nucleotides differ between what are almost certainly alleles of the DR beta 1 locus. All differences were in the first domain of the molecule and all localized to a region from amino acids 71-86. Because all differences were found only in this region of the molecule, and because DR alpha-chains seem to be relatively non-polymorphic, these positions in the DR beta-chain must have a major role in influencing T-cell recognition of the DR molecule.
mesh_terms: D000483:Alleles; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II / Q000235:genetics*; D006801:Humans; D011110:Polymorphism, Genetic; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D004247:DNA