P-glycoprotein epitope mapping. I. Identification of a linear human-specific epitope in the fourth loop of the P-glycoprotein extracellular domain by MM4.17 murine monoclonal antibody to human multi-drug-resistant cells

Int J Cancer. 1994 Jan 2;56(1):153-60. doi: 10.1002/ijc.2910560127.


A new murine monoclonal antibody (MAb), MM4.17, to human multi-drug-resistant (MDR) cells was found to be reactive in an ELISA with a synthetic 16-amino acid peptide selected from the fourth loop of the P-glycoprotein extracellular domain. Immunohistochemistry indicated that this MAb reacted in human tissues in the same pattern as that previously found with other human-specific MAbs to P-glycoprotein. For a precise definition of the MM4.17 epitope, a peptide library consisting of overlapping 4- to 10-mer residues covering the entire P-glycoprotein-fragment was synthesized on polyethylene pins and tested for MAb binding. The results of this ELISA demonstrated that the MM4.17 epitope is constituted by the continuous-linear TRIDDPET amino-acid sequence (residues 750-757 of the human MDRI-P-glycoprotein). The MAb MM4.17 recognizes only the human MDRI-P-glycoprotein isoform, and excess TRIDDPET peptide blocks the binding of the MAb to MDR variants of CEM cells. These results demonstrate that the amino-acid sequence TRIDDPET from the human MDRI gene represents the first continuous-linear epitope identified in the P-glycoprotein extracellular domain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal / immunology*
  • Antibody Specificity
  • Carrier Proteins / genetics
  • Carrier Proteins / immunology*
  • Cell Line
  • Drug Resistance / genetics
  • Drug Resistance / immunology
  • Enzyme-Linked Immunosorbent Assay / methods
  • Epitopes / analysis*
  • Humans
  • Hybridomas / immunology
  • Immunohistochemistry
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / immunology*
  • Mice
  • Mice, Inbred BALB C
  • Molecular Sequence Data
  • Peptide Fragments / genetics
  • Peptide Fragments / immunology*
  • Structure-Activity Relationship


  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • Antibodies, Monoclonal
  • Carrier Proteins
  • Epitopes
  • Membrane Glycoproteins
  • Peptide Fragments