The refolding efficiency of the different antibodies is also different, especially Fragment scFv
E.coli expression system for the expression of the different active rAbs exist different expression site, including secreted into the extracellular periplasmic space, the outer membrane or the internal and cytoplasm. Use of a promoter such as lac, trp and tac induce antibody expression, these promoters can be lac obstructions regulation and isopropyl-β-galactosidase (IPTG) induction. Cytoplasmic reduced case, the expression can be obtained the high concentrations of antibody, but is easy to accumulate the formation of inclusion bodies, denaturing reagent therefore need to be processed, and then refolding. The refolding efficiency of the different antibodies is also different, especially Fragment scFv. Gou, etc. The method of using nickel chelate chromatography column refolding from inclusion bodies, the successful refolding concentration is greater than 40 mg / L having the activity of IP10-scFv fusion protein. Addition of scFv expression in the pelB leader sequence regulation and under oxidizing conditions, secreted into the periplasm or E. coliα-hemolysin (hyla) system secreted into the medium supernatant. HylA is E. coli outer membrane is formed between the type I protein secretion channel hemolytic toxin secreted by the protein channel. This system has been proved to have secretion, including scFv, including exogenous protein capacity.