A murine monoclonal antibody (928) recognizing a new epitope formed with a combination of HLA-DPA1*0201 and DPB1*0301 gene products

Hum Immunol. Aug-Sep 1997;56(1-2):114-24. doi: 10.1016/s0198-8859(97)00143-2.


A murine monoclonal antibody (mAb), 928, that recognizes a cell surface antigen (928 Ag) on a human Epstein-Barr virus-transformed fetal liver-derived lymphoid progenitor cell line (FL4.4) was generated. The 928 mAb reacted with only FL4.4; it did not react with any other 57 cell lines tested. Two color flowcytometry analysis of peripheral blood mononuclear cells (PBMC) revealed that the 928 mAb reacted with B cell and monocyte fractions from only two individuals out of 63 unrelated donors. Biochemical analyses showed that the 928 Ag composes of two molecules (33 and 34 Kd) and forms a SDS-resistant, noncovalently linked dimer conformation, the feature being similar to that of peptide-bound MHC class II molecules. Treatment of FL4.4 cells with the 928 mAb significantly facilitated homotypic cell aggregation. In addition, treatment of PBMC of the 928 Ag+ donor with recombinant IL-4 augmented the expression of the 928 Ag on CD64+ monocytes. Typing of HLA-DRB1, DPA1 and DPB1 alleles of the 928 Ag expressing and nonexpressing cells revealed that the 928 Ag is expressed only on PBMC of HLA-DPA1*0201 and DPB1*0301 positive donors. Finally, anti-DP antibody precleared 928 Ag from the cell lysate. These results demonstrate that the 928 mAb recognizes a polymorphic determinant of HLA-DPA1*0201-DPB1*0301 gene products. The possibility that amino acids in the groove of the peptide-binding site of HLA-DP molecules are critical for the 928 epitope is discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal / immunology*
  • Antibody Specificity
  • Antigens, Surface / immunology
  • Cell Aggregation
  • Epitopes / analysis*
  • Epitopes / chemistry
  • Gene Expression
  • Genes, MHC Class II
  • HLA-DP Antigens / chemistry
  • HLA-DP Antigens / immunology*
  • Humans
  • Hybridomas / immunology
  • Interleukin-4 / immunology
  • Leukocytes, Mononuclear / immunology
  • Mice
  • Mice, Inbred BALB C


  • Antibodies, Monoclonal
  • Antigens, Surface
  • Epitopes
  • HLA-DP Antigens
  • Interleukin-4