An anti-PR1/HLA-A2 T-cell receptor-like antibody mediates complement-dependent cytotoxicity against acute myeloid leukemia progenitor cells

Blood. 2011 Apr 21;117(16):4262-72. doi: 10.1182/blood-2010-07-299248. Epub 2011 Feb 4.


PR1 (VLQELNVTV) is a human leukocyte antigen-A2 (HLA-A2)-restricted leukemia-associated peptide from proteinase 3 (P3) and neutrophil elastase (NE) that is recognized by PR1-specific cytotoxic T lymphocytes that contribute to cytogenetic remission of acute myeloid leukemia (AML). We report a novel T-cell receptor (TCR)-like immunoglobulin G2a (IgG2a) antibody (8F4) with high specific binding affinity (dissociation constant [K(D)] = 9.9nM) for a combined epitope of the PR1/HLA-A2 complex. Flow cytometry and confocal microscopy of 8F4-labeled cells showed significantly higher PR1/HLA-A2 expression on AML blasts compared with normal leukocytes (P = .046). 8F4 mediated complement-dependent cytolysis of AML blasts and Lin(-)CD34(+)CD38(-) leukemia stem cells (LSCs) but not normal leukocytes (P < .005). Although PR1 expression was similar on LSCs and hematopoietic stem cells, 8F4 inhibited AML progenitor cell growth, but not normal colony-forming units from healthy donors (P < .05). This study shows that 8F4, a novel TCR-like antibody, binds to a conformational epitope of the PR1/HLA-A2 complex on the cell surface and mediates specific lysis of AML, including LSCs. Therefore, this antibody warrants further study as a novel approach to targeting leukemia-initiating cells in patients with AML.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Complement System Proteins / immunology*
  • Cytotoxicity, Immunologic / immunology*
  • Epitopes / immunology*
  • HLA-A2 Antigen / immunology*
  • Humans
  • Leukemia, Myeloid, Acute / immunology*
  • Leukemia, Myeloid, Acute / pathology
  • Leukocytes / immunology
  • Leukocytes / pathology
  • Mice
  • Mice, Inbred BALB C
  • Receptors, Antigen, T-Cell / immunology*
  • Receptors, IgG / immunology
  • Stem Cells / immunology


  • Epitopes
  • HLA-A2 Antigen
  • Receptors, Antigen, T-Cell
  • Receptors, IgG
  • Complement System Proteins