抗CD3/抗CD20双特异双链抗体的生物学活性研究

目的研究抗CD3/抗CD20双特异双链抗体的生物学活性.方法采用亲和层析法纯化本室构建的抗CD3/抗CD20双特异双链抗体可溶性表达产物,并用SDS-PAGE,Westernblot和分子排阻层析鉴定纯化产物;采用FACS法和玫瑰花环试验测定纯化产物与靶细胞的结合活性;采用3H-TdR掺入实验和51Cr释放试验测定该双特异双链抗体的生物学性质.结果纯化的抗CD3/抗CD20双特异双链抗体具有与Jurkat(CD3+)和Daudi细胞(CD20+)的结合活性,且能同时与Jurkat和Daudi细胞结合形成玫瑰花环,并能竞争性封闭亲代鼠源性抗体HIT3a和HI47与Jurkat和Daudi细胞的结合位点;该双特异双链抗体具有促有丝分裂原作用和介导激活的T细胞杀伤Daudi细胞的活性.结论抗CD3/抗CD20双特异双链抗体具有与亲代鼠源性抗体HIT3a和HI47相同的性质,且能介导激活的T细胞杀伤表达CD20抗原的肿瘤细胞,是一个有望用于B细胞恶性肿瘤临床治疗的双特异性抗体.

Study on the biological activity of anti-CD3/anti-CD20 diabody

Objective To study the biological activity of anti CD3/anti CD20 diabody. Methods The anti CD3/anti CD20 diabody was purified by affinity chromatography and analyzed by both Western blot and size exclusion chromatography. Its antigen binding activity was examined by FACS and rosetting assay; its biological activity was examined by 3H TdR incorporation and 51 Cr release test. Results The anti CD3/anti CD20 diabody bound to Jurkat cells (CD3 ) and Daudi cells(CD20 ) and block the sites where parent antibody bind to. Furthermore, it was found to have effective mitogenic activity and the effect on retargeting peripheral blood lymphocytes to lyse Daudi cells. Conclusion The biological activity of anti CD3/anti CD20 diabody is the same as its parent antibodies. The diabody proved to be a potent agent for retargeting peripheral blood lymphocytes to tumor cells expressing the CD20 antigen and then lyse them.