Construction and Expression of the Anti-TNF-α ScFv Gene

To construct an anti TNFαsingle chain Fv gene and to express and purify it in E.coli . The VH and VL genes of anti TNFαmAb were connected into ScFv gene by a flexible linker and the ScFv gene fragments were inserted into expression vector pQE30. The recombinant plasmid were transfected into E.coli M15 and the expression of target protein was induced with IPTG. The expressed protein was purified using Ni NTA resin. The results showed that the length of ScFv gene fragments was 723 bp and the sequence was correct. SDS PAGE indicated that the recombinant plasmid pQE30 expressed a new protein band with a M r about 52 000 with the purity of the product 90%. Thus, the ScFv gene was sucessfully constructed and highly expressed in E.coli , and purified recombinant protein was obtained.