一种新型重组抗体导向溶栓剂的体外溶栓研究

Study on thrombolysis of a new recombinant antibody targeted plasminogen activator in vitro

目的 :探讨一种新型重组融合基因抗体导向溶栓剂SZ5 1Hu scuPA的体外溶栓效力。方法 :通过转瓶扩大生产获得的大量基因重组融合蛋白SZ5 1Hu scuPA ,通过抗体竞争结合实验确定融合蛋白的抗体亲和力 ;进而与尿激酶进行不同浓度血小板血浆凝块体外溶栓比较。结果 :该融合蛋白体外纤溶活性为 390 0 0U mg ;其抗体亲和力是鼠源性单抗的 6 7% ;体外溶栓效力较uPA提高 4.1～ 8.4倍。结论 :体外溶栓结果证明 ,融合蛋白SZ5 1Hu scuPA既兼有与人活化血小板结合特性又有纤溶酶原激活剂特性的双功能分子 。

Objective:To compare the thrombolytic properties in vitro between urokinase(uPA) and the recombinant chimeric plasminogen activator SZ51Hu scuPA,which was composed of a humanized monoclonal antibody SZ51(SZ51Hu) specifically against activated human platelet and a single chain urokinase(scuPA).Methods:The fusion protein SZ51Hu scuPA was produced from the supernatant of a stable myeloma cell line growing in spinner flask,and then purified by chromatography on a GAH IgG Sepharose 4B affinity column.The binding capacity to activted human platelet of purified fusion protein SZ51Hu scuPA was obtained by antibody competitive binding assay.The thrombolytic activity was determined by lysis of 125 I fibrin labelled human plasma clots.Results:SZ51Hu scuPA affinity was 67% of the SZ 51M and the fibrinolytic activity was 39 000 U/mg. The lysis of the clots by SZ51Hu scuPA was 4.1～8.4 fold more potent than uPA.Conclusion:The fusion protein SZ51Hu scuPA was more competent to dissolve platelet clots than uPA and it was a new recombinant antibody targeted plasminogen activator in vitro.