A human monoclonal antibody reacting against HLA-DQ1-, DQ4-, and a subset of DQ7-bearing cells

Hum Immunol. 1993 Feb;36(2):81-90. doi: 10.1016/0198-8859(93)90110-m.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antibodies, Monoclonal / immunology*
  • Antigen-Antibody Reactions
  • B-Lymphocytes / immunology*
  • Binding, Competitive / immunology
  • Cell Line
  • Cell Transformation, Viral
  • Epitopes / immunology
  • Fluorescent Antibody Technique
  • HLA-DQ Antigens / immunology*
  • HLA-DR Antigens / immunology
  • Herpesvirus 4, Human
  • Humans
  • Molecular Sequence Data
  • Polymorphism, Restriction Fragment Length
  • Tumor Cells, Cultured


  • Antibodies, Monoclonal
  • Epitopes
  • HLA-DQ Antigens
  • HLA-DQ1 antigen
  • HLA-DQ4 antigen
  • HLA-DQ7 antigen
  • HLA-DR Antigens