Urokinase-type plasminogen activator enhances invasion of human T cells (Jurkat) into a fibrin matrix.
The receptor for urokinase-type plasminogen activator (uPA-R) localizes uPA to the cell surface. The receptor-bound uPA converts plasminogen to the trypsin-like endopeptidase plasmin. Thus uPA is involved in the initiation of pericellular proteolysis. Pericellular proteolysis is assumed to facilitate the cellular infiltration into surrounding tissue. The uPA-R has recently been identified as a surface antigen of activated human T lymphocytes. We have characterized the uPA-R of the human CD4 T cell line Jurkat by immunological (flow cytometry), biochemical (ligand blotting), and physico-chemical (Scatchard blotting) methods. The collective data suggest that the human CD4+ T cell line Jurkat expresses a cell surface receptor for uPA similar to that of myelo/monocytes and normal T cells with regard to size, affinity, ligand specificity, and antigenicity. Binding studies using exogenous uPA and subsequent functional assays revealed that receptor-bound uPA retains its enzymatic activity. Saturation of the Jurkat cell uPA-R with exogenous uPA facilitated cellular invasion into fibrin matrices in vitro. uPA-dependent invasion was inhibited in the presence of an anti-catalytic monoclonal anti-uPA antibody. We propose that uPA-R-bound uPA may facilitate the invasiveness of uPA-R-positive T lymphocytes.
Kramer
M D
MD
Institute for Immunology and Serology, University of Heidelberg Im Neuenheimer Feld 305, Germany.
Spring
H
H
Todd
R F
RF
Vettel
U
U
D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000201:enzymology / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D005109:Extracellular Matrix / Q000502:physiology*; D005337:Fibrin / Q000502:physiology*; D006801:Humans; D011956:Receptors, Cell Surface / Q000378:metabolism; D055293:Receptors, Urokinase Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism* / Q000502:physiology
C524898:PLAUR protein, human; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D005337:Fibrin; D014568:Urokinase-Type Plasminogen Activator