[Construction and expression of diabody [CD3 x Pgp] without Etag].

AIM: To construct and express a diabody [CD3×Pgp] without Etag and analyse its biological activity. METHODS: In this study, the diabody [CD3×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×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×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.