关键词: 噬菌体展示：单链抗体, DNA改组, 导向溶栓剂, 尿激酶

Abstract: Fibrin-specific antibodies were isolated from a phage-displayed single-chainantibody(ScAb) library using affinity selection or panning. DNA shuffling was introduced to realign the specific antibody genes in order to mimic the antibody maturation in vivo. After cloning of shuffling products, a secondary library was constructed, from which the specific antibody against fibrin with higher activity was selected through panning and screening. The fibrin-specific antibody gene and uPA functional domain gene fragment were joined together, then inserted into expression plasmid pET-21a. The ScAb/uPA fusion protein was expressed with the induction of IPTG. In substrate S₂₄₄₄ assay, the uPA activity of the chimera was about 3.1*10³ IU/mg periplasmic protein of host E.coli. It also kept up the affinity to fibrin.

Key words: phage display, single-chain antibody, DNA shuffling, targeted thrombolytics, urokinase