Sustained thromboprophylaxis mediated by an RBC-targeted pro-urokinase zymogen activated at the site of clot formation Academic Article uri icon


MeSH Major

  • Drug Delivery Systems
  • Enzyme Precursors
  • Erythrocytes
  • Fibrinolytic Agents
  • Prodrugs
  • Recombinant Fusion Proteins
  • Single-Chain Antibodies
  • Thrombosis
  • Urokinase-Type Plasminogen Activator


  • Plasminogen activators (PAs) are used to treat life-threatening thrombosis, but not for thromboprophylaxis because of rapid clearance, risk of bleeding, and central nervous system (CNS) toxicity. We describe a novel strategy that may help to overcome these limitations by targeting a thrombin-activated PA pro-drug to circulating red blood cells (RBCs). We fused a single chain antibody (scFv Ter-119) that binds to mouse glycophorin A (GPA) with a variant human single-chain low molecular weight urokinase construct that can be activated selectively by thrombin (scFv/uPA-T). scFv/uPA-T bound specifically to mouse RBCs without altering their biocompatibility and retained its zymogenic properties until converted by thrombin into an active 2-chain molecule. As a result, RBC-bound scFv/uPA-T caused thrombin-induced fibrinolysis. One hour and 48 hours after intravenous (IV) injection in mice, approximately 70% and approximately 35% of scFv/uPA-T was retained in the blood, respectively, and approximately 95% of the circulating scFv/uPA-T remained bound to RBCs. A single IV injection of scFv/uPA-T provided effective prophylaxis against arterial and venous thrombosis for up to 24 hours. Thus, prophylactic delivery of RBC-targeted PA pro-drugs activated selectively at the site of clot formation represents a new approach to prevent thrombosis in clinical settings where the risk of clotting is high.

publication date

  • June 24, 2010



  • Academic Article



  • eng

PubMed Central ID

  • PMC2892950

Digital Object Identifier (DOI)

  • 10.1182/blood-2010-01-261610

PubMed ID

  • 20410503

Additional Document Info

start page

  • 5241

end page

  • 8


  • 115


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