title: A human monoclonal antibody reacting against HLA-DQ1-, DQ4-, and a subset of DQ7-bearing cells.
abstract: Human mAb 2A2 recognizes an epitope present in the HLA-DQ1 + 4 specifications and also on several DQ7-positive cells. We have investigated the extra reactions of this monoclonal reagent on a wider panel of DQ1-, DQ4-negative/DQ7-positive B-cell lines. The results obtained support the existence of two subtypes of the HLA-DQ7 specificity on the basis of their reactivity with human mAb 2A2; the DQ7/2A2-positive variant has been found in 12 of 29 BCLs positive for the DR11 antigen, and in four of eight BCLs bearing DR4-DQ7 haplotypes. It has also been detected in the DR12-positive cells assayed and in several unusual DR/DQ7 combinations not commonly found in Caucasoid populations, including the DR13-DwHAG and DR14-Dw16 haplotypes. Results from competition binding assays between 2A2 and well-characterized murine anti-DQ polymorphic mAbs suggest that the epitope recognized by human mAb 2A2 on DQ1- or DQ4-bearing haplotypes is located on the DQ beta chains of such specificities, being amino acid residues 54-55, the potential binding site of antibody 2A2, whereas the binding site on DQ7 antigens cannot be explained on the basis of known amino acid sequences.
authors.affiliation: Immunology Center, Virgin of Rocío University Hospital, Andaluz de Salud Center, Seville, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Sánchez
authors.forename: O
authors.initials: O
authors.lastname: de la Calle
authors.forename: J
authors.initials: J
authors.lastname: Yélamos
authors.forename: I
authors.initials: I
authors.lastname: Aguilera
authors.forename: F
authors.initials: F
authors.lastname: Sánchez
authors.forename: V
authors.initials: V
authors.lastname: Dessi
authors.forename: S
authors.initials: S
authors.lastname: Siervo
authors.forename: J R
authors.initials: JR
authors.lastname: García-Lozano
authors.forename: J
authors.initials: J
authors.lastname: Melero
authors.forename: R
authors.initials: R
authors.lastname: Magariño
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000937:Antigen-Antibody Reactions; D001402:B-Lymphocytes / Q000276:immunology*; D001667:Binding, Competitive / Q000276:immunology; D002460:Cell Line; D002472:Cell Transformation, Viral; D000939:Epitopes / Q000276:immunology; D005455:Fluorescent Antibody Technique; D006683:HLA-DQ Antigens / Q000276:immunology*; D006684:HLA-DR Antigens / Q000276:immunology; D004854:Herpesvirus 4, Human; D006801:Humans; D008969:Molecular Sequence Data; D012150:Polymorphism, Restriction Fragment Length; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D006683:HLA-DQ Antigens; C051568:HLA-DQ1 antigen; C060029:HLA-DQ4 antigen; C069546:HLA-DQ7 antigen; D006684:HLA-DR Antigens