Enhanced production and single step purification of biologically active recombinant anti-IL6 scFv from Escherichia coli inclusion bodies

Interleukin 6 (IL-6) is a proinflammatory cytokine that plays a critical role in immune responses and inflammation. Overexpression of IL-6 serves as a biomarker for various diseases. Therefore, it is vital to develop IL-6-specific antibodies for the diagnosis and treatment of inflammatory diseases. Alternatively, high-yield production of single-chain variable fragments (scFv) in prokaryotes reduces the time and cost required while attaining a similar specificity. However, overexpression of eukaryotic proteins in bacterial expression systems often leads to the formation of inclusion bodies. Here, a codon-optimized anti-IL6 scFv was expressed in the E. coli SHuffle strain, and the effects of inclusion body solubilisation methods on the product yield were investigated. A high concentration (23 mg/L) of biologically active and pure (>95 %) scFv was obtained without any need for a refolding step following solubilisation with a non-denaturing solubilisation agent, N-lauroyl sarcosine. Activity assays showed that anti-IL6 scFv could specifically bind to its antigen. Overall, we present reproducible and efficient production of anti-IL6 scFv in E. coli by using a one-step purification method. While the biologically active and pure antibody fragment can be used for diagnostic studies of the IL-6 cytokine, the developed method can be applied to other recombinant proteins expressed in E. coli.