title: Polymorphic DQ alpha and DQ beta interactions dictate HLA class II determinants of allo-recognition.
abstract: 18 transfected cell lines were generated that expressed distinct DQ molecules related to the serologically defined HLA-DQw3 specificity. These transfectants were constructed using site-directed mutagenesis to introduce nucleotide substitutions into DQ3.2 beta cDNA, followed by retrovirus-mediated gene expression of the mutagenized genes in human B cell lines with different endogenous DQ alpha chains. The capacity of particular class II dimers to stimulate alloreactive T cell clones was investigated. T cell activation was found to be dependent on both DQ alpha and DQ beta chains. In some cases, single amino acid substitutions at codons 13, 26, 45, or 57 of the DQ beta chain were sufficient to dramatically alter T cell reactivity; T cell recognition of these substitutions, however, was strongly influenced by the alpha chain polymorphisms present in the stimulatory class II dimer. Both gain and loss of major serologic and cellular specificities associated with specific DQw3+ alleles were observed with a limited array of site-directed substitutions.
authors.affiliation: Virginia Mason Research Center, Seattle, WA 98101.
authors.forename: W W
authors.initials: WW
authors.lastname: Kwok
authors.forename: E
authors.initials: E
authors.lastname: Mickelson
authors.forename: S
authors.initials: S
authors.lastname: Masewicz
authors.forename: E C
authors.initials: EC
authors.lastname: Milner
authors.forename: J
authors.initials: J
authors.lastname: Hansen
authors.forename: G T
authors.initials: GT
authors.lastname: Nepom
mesh_terms: D000595:Amino Acid Sequence; D001402:B-Lymphocytes / Q000276:immunology; D001483:Base Sequence; D002460:Cell Line; D015870:Gene Expression; D005802:Genes, MHC Class II; D005822:Genetic Vectors; D006683:HLA-DQ Antigens / Q000235:genetics*; D006801:Humans; D007519:Isoantigens / Q000235:genetics*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009154:Mutation; D015345:Oligonucleotide Probes; D011110:Polymorphism, Genetic; D012689:Sequence Homology, Nucleic Acid; D013601:T-Lymphocytes / Q000276:immunology; D014162:Transfection
chemical_list: D006683:HLA-DQ Antigens; D007519:Isoantigens; D046911:Macromolecular Substances; D015345:Oligonucleotide Probes