Inhibition of cell surface mediated plasminogen activation by a monoclonal antibody against alpha-Enolase

Am J Hematol. 2003 Apr;72(4):234-42. doi: 10.1002/ajh.10299.


Localization of plasmin activity on leukocyte surfaces plays a critical role in fibrinolysis as well as in pathological and physiological processes in which cells must degrade the extracellular matrix in order to migrate. The binding of plasminogen to leukocytic cell lines induces a 30- to 80-fold increase in the rate of plasminogen activation by tissue-type (tPA) and urokinase-type (uPA) plasminogen activators. In the present study we have examined the role of alpha-enolase in plasminogen activation on the cell surface. We produced and characterized a monoclonal antibody (MAb) 11G1 against purified alpha-enolase, which abrogated about 90% of cell-dependent plasminogen activation by either uPA or tPA on leukocytoid cell lines of different lineages: B-lymphocytic, T-lymphocytic, granulocytic, and monocytic cells. In addition, MAb 11G1 also blocked enhancement of plasmin formation by peripheral blood neutrophils and monocytes. In contrast, MAb 11G1 did not affect plasmin generation in the presence of fibrin, indicating that this antibody did not interact with fibrinolytic components in the absence of cells. These data suggest that, although leukocytic cells display several molecules that bind plasminogen, alpha-enolase is responsible for the majority of the promotion of plasminogen activation on the surfaces of leukocytic cells.

Publication types

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

MeSH terms

  • Adenocarcinoma / enzymology
  • Adenocarcinoma / pathology
  • Antibodies, Monoclonal / drug effects
  • Antibodies, Monoclonal / pharmacology*
  • B-Lymphocytes / pathology
  • Blood Cells / drug effects
  • Blood Cells / metabolism
  • Breast Neoplasms / enzymology
  • Breast Neoplasms / pathology
  • Carboxypeptidase B
  • Carboxypeptidases / pharmacology
  • Depression, Chemical
  • Female
  • Fibrin / metabolism
  • Fibrinogen / metabolism
  • Fibrinolysin / biosynthesis*
  • Fibrinolysis / drug effects
  • Humans
  • Leukocytes / enzymology
  • Neoplasm Invasiveness
  • Neoplasm Proteins / antagonists & inhibitors*
  • Neoplasm Proteins / immunology
  • Peptide Fragments / metabolism
  • Phosphopyruvate Hydratase / antagonists & inhibitors*
  • Phosphopyruvate Hydratase / immunology
  • Plasminogen / metabolism*
  • Protein Binding
  • Subcellular Fractions / drug effects
  • Thrombin / metabolism
  • Tissue Plasminogen Activator / metabolism
  • Tumor Cells, Cultured / drug effects
  • Tumor Cells, Cultured / enzymology
  • Urokinase-Type Plasminogen Activator / metabolism


  • Antibodies, Monoclonal
  • Neoplasm Proteins
  • Peptide Fragments
  • lysyl-plasminogen
  • Fibrin
  • Fibrinogen
  • Plasminogen
  • Carboxypeptidases
  • Carboxypeptidase B
  • Thrombin
  • Tissue Plasminogen Activator
  • Fibrinolysin
  • Urokinase-Type Plasminogen Activator
  • Phosphopyruvate Hydratase