Thrombin activation and fibrinolytic activity of RBC-bound and soluble scFv/uPA-T in vitro. (A) Lysis of ¹²⁵I-labeled fibrin clots by mouse or human RBCs (mRBCs; hRBCs) preincubated for 1 hour in medium containing scFv/uPA-T, with or without activation by thrombin (n = 3). (B) Kinetics of scFv/uPA-T activation by thrombin. ● shows nonactivated scFv/uPA-T. (C) Fibrinolytic activity of RBC-bound or free scFv/uPA-T at the indicated concentrations using clots prepared from PPP. Clot lysis was monitored for 0 to 4 hours (n = 3).