The expression of single chain Fv fragment of monoclonal antibody against activated platelets in E.coli

Objective To reduce immunogenicity and molecular weight of a monoclonal antibody specific for activated human platelet and to express single chain Fv fragment (ScFv) in E.coli . Methods Two expression vectors of SZ-51 ScFv, pHEN1-51 ScFv and pET20b-51 ScFv, were constructed and transformed into E.coli strain HB2151 and BL21(DE3) plys, respectively. The expressed recombinant proteins were analysed. Results Induced by IPTG, HB2151 secreted soluble SZ-51 ScFv to the cultured supernatant. The BL21 (DE3) plys expressed the SZ-51 ScFv the soluble recombinant protein and insoluble recombinant protein in inclusion bodies and constituted 20% of the total cell protein. Western blot analysis showed that the SZ-51 ScFv obtained from two strains of E.coli maintained the binding activity to activated human platelet as their parent ones. Conclusion The results showed that the pET20b expression system is stable and efficient for expressing SZ-51 ScFv. However, the denaturation and protein refolding of the SZ-51 ScFv expressed in inclusion bodies need to be studied further.