High-efficient refolding and purification of recombinant human interleukin-2 from inclusion bodies

Human interleukin-2 (hIL-2) serves as a crucial cytokine in the treatment of cancer and autoimmune disorders. Nevertheless, the advancement of research and clinical applications involving this cytokine has been hindered by the constraints associated with the production of recombinant human interleukin-2 (rhIL-2). This study presents a scalable and robust purification protocol for rhIL-2 derived from inclusion bodies (IBs) in Escherichia coli. Our results indicate that microfiltration-based method could improve the purity of the denatured IBs effectively, and various refolding conditions were assessed to improve the recovery of refolded rhIL-2, resulting in an increase in the refolding yield from 15 % to 45 %. Subsequently, purification through three-column chromatography could refine the refolded rhIL-2 efficiently. Ultimately, the robustness of the purification process is substantiated by three consecutive scale-up experiments, achieving a productivity of 4 mg rhIL-2/g cell pellets, alongside high product purity and significant product activity.