A lymphocyte cell surface heat shock protein homologous to the endoplasmic reticulum chaperone, immunoglobulin heavy chain binding protein BIP

Int J Cancer. 1997 Jun 11;71(6):1077-85. doi: 10.1002/(sici)1097-0215(19970611)71:6<1077::aid-ijc26>3.0.co;2-9.

Abstract

BE2 is a cell surface monomeric 78-kDa protein (BE2-78) expressed on the malignant lymphocytes of cutaneous T-cell lymphoma and adult T-cell leukemia, on some lymphocytes from patients with acquired immunodeficiency syndrome and on Epstein-Barr virus-transformed B cells. BE2-78 positivity of cutaneous T-cell lymphoma tumor cells is a useful diagnostic and prognostic determinant in evaluating patients with that disorder. The BE2-78 protein was isolated from Epstein Barr virus-transformed B cells, purified by 1- and 2-dimensional electrophoresis and then sequenced. The sequence of 4 isolated peptide fragments was highly homologous with the 78-kDa heat shock protein, BiP, an endoplasmic reticulum chaperone. The similarity between BiP and BE2-78 was supported by the demonstration that BE2-78, like BiP, avidly binds to ATP. However, polyclonal and monoclonal reagents that recognize cytoplasmic 70- and 78-kDa heat shock proteins do not detect the BE2-78 antigen on the cell surface of cutaneous T-cell lymphoma or Epstein Barr virus-transformed lymphocytes, and peptide mapping demonstrates sequence divergence, suggesting that either they are distinct or conformationally different molecules. Our results indicate that BE2-78 is a cell surface heat shock protein. The possibility that malignant or transformed lymphocytes may express cell surface molecules with the capacity to bind a spectrum of exogenous or endogenous peptides has potential implications for tumor immunology.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Amino Acid Sequence
  • Antigens, Surface / chemistry*
  • Antigens, Surface / metabolism
  • Blotting, Western
  • Carrier Proteins / chemistry*
  • Carrier Proteins / metabolism
  • Cell Line
  • Cell Membrane / chemistry
  • Heat-Shock Proteins / chemistry*
  • Heat-Shock Proteins / metabolism
  • Isoelectric Focusing
  • Molecular Chaperones / chemistry*
  • Molecular Chaperones / metabolism
  • Molecular Sequence Data
  • Protein Binding
  • Sequence Homology, Amino Acid

Substances

  • Antigens, Surface
  • Carrier Proteins
  • Heat-Shock Proteins
  • Molecular Chaperones
  • Adenosine Triphosphate
  • molecular chaperone GRP78