去除Etag标记的抗CD3/抗Pgp微型双功能抗体原核表达载体的构建及表达

目的:构建和表达不带Etag标记的抗CD3/抗Pgp微型双功能抗体(Diabody[CD3×Pgp]),并测定其生物学活性。方法:利用PCR方法构建不带Etag的Diabody[CD3×Pgp]原核表达载体,进行原核表达,制备抗抗CD3scFv亲和层析柱进行纯化,SDS-PAGE鉴定。通过间接免疫荧光法和竞争性免疫荧光结合流式细胞术(FCM)检测生物学活性。结果:无Etag的Diabody[CD3×Pgp]表达载体经测序证实其序列正确。SDS-PAGE电泳显示2条带,相对分子质量(Mr)分别为25000和26000,与预期Mr相符。去除Etag的Dia-body[CD3×Pgp]与K562/A02和Jurkat细胞结合阳性率分别为89.87%和83.95%。竞争结合实验中,与K562/A02和Jurkat细胞竞争后结合率分别为50.25%和43.78%。结论:成功构建了不带Etag的Diabody[CD3×Pgp]表达载体、进行原核表达及纯化。不带Etag的Diabody[CD3×Pgp]能特异性结合CD3和Pgp靶抗原,Etag标记去除后其生物学活性没有降低。

Construction and expression of diabody[CD3×Pgp ] without Etag

AIM: To construct and express a diabody [CD3 x Pgp] without Etag and analyse its biological activity. METHODS: In this study, the diabody [CD3 x Pgp] was obtained by PCR and restriction cleavage, and expressed in E.coli 16C9. The product was purified by anti-anti-CD3 scFv affinity chromatography and verified through SDS-PAGE electrophoresis. Flow cytometry(FCM) was used to analyse the bingding properties and competitive bingding capacity. RESULTS: The sequence of diabody [CD3 x Pgp] without Etag was correct. It migrated as two bands with the expected molecular weight(25 kD and 26 kD) in SDS-PAGE. The binding rate to CD3 and Pgp antigen was 83.95% and 89.87% respectively. The competitive bingding rate to CD3 and Pgp was 43.78% and 50.25% respectively. CONCLUSION: The diabody [CD3 x Pgp] without Etag has been successfully constructed, expressed and purified. The product can bind to CD3 and Pgp antigen specifically, and its biological activity doesn't decrease.