title: Structural analysis of an HLA-B7 antigen variant detected by cytotoxic T lymphocytes.
abstract: It has been demonstrated previously that lymphocytes of donor CF (HLA-A29,w33; B7,14) are not recognized by the HLA-B7-specific CTL clone HG-31. This report presents a structural comparison of the HLA-B7 antigen of donor CF with a "normal" HLA-B7 antigen, derived from the cell line JY. Isoelectric focusing showed that CF HLA-B7 heavy chains were more acidic than JY HLA-B7 heavy chains by the equivalent of a single charge. High pressure liquid chromatography and ion exchange chromatography comparisons of double-labeled tryptic peptides revealed a single detectable difference, which corresponded to the tryptic peptide spanning residues 112 to 121 on the HLA-B7 heavy chain. Although the complete amino acid sequence of this peptide was not obtained, the partial sequence indicates a substitution of an unidentified amino acid for tyrosine at position 116 of the heavy chain. This residue is found to vary among HLA specificities and to be altered in many H-2Kb mutants.
mesh_terms: D000595:Amino Acid Sequence; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D014644:Genetic Variation; D006680:HLA Antigens / Q000235:genetics; D015793:HLA-B7 Antigen; D006801:Humans; D007143:Immunoglobulin Heavy Chains; D007525:Isoelectric Focusing; D010446:Peptide Fragments / Q000032:analysis; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D006680:HLA Antigens; D015793:HLA-B7 Antigen; D007143:Immunoglobulin Heavy Chains; D010446:Peptide Fragments