抗Pgp/抗CD3双特异双链抗体的生物学活性研究

目的　研究抗Pgp 抗CD3双特异双链抗体介导的特异性靶向杀伤活性。方法　采用亲和层析法分离纯化本室构建的抗Pgp 抗CD3双特异双链抗体可溶性表达产物 ,并用SDS PAGE、Westernblot及抗活细胞间接免疫荧光法鉴定纯化产物 ;采用51 Cr释放试验测定其介导的体外靶向杀伤活性。结果　纯化的抗Pgp 抗CD3双特异双链抗体具有与Jurkat细胞 (CD3 )和K5 6 2 A0 2 (Pgp )细胞结合的活性 ;抗Pgp 抗CD3双特异双链抗体具有介导激活的T淋巴细胞杀伤Pgp表达阳性的耐药肿瘤细胞的作用 ,杀伤作用的强弱显示出效靶比和剂量依赖关系 ,且可被CD3ScFv或PgpScFv特异性的阻断。结论　抗Pgp 抗CD3微型双功能抗体有望成为治疗耐药肿瘤 ,特别是肿瘤残留灶和微小转移灶的治疗的一种新策略。

Biological activity of anti-CD3/anti-Pgp diabody

Objective To study the biological activity of anti-CD3/anti-Pgp diabody. Methods The anti-CD3/anti-Pgp diabody was purified by affinity chromatography and analyzed by Western blot and size exclusion chromatography;its antigen-binding activity was examined by FACS. Its biological activity was examined by 51 Cr release test. Results The anti-CD3/anti-Pgp diabody can bind to Jurkat cells (CD3 ) and K562/A02 cells(Pgp ). In the presence of activated human peripheral blood lymphocytes (PBL), the diabody mediates effectively the lysis of the Pgp-overexpressing human leukemia K562/A02, but is much less potent in mediating the lysis of the parent K562. Conclusion The biological activity experiments demonstrated that the diabody the anti-Pgp/anti-CD3 diabody may have great potential in the treatment of MDR cancers.