Optimized Purification and Characterization of Recombinant Human Interleukin-2 (Rhil-2) Using a His-Mbp Fusion System

Recombinant human interleukin-2 (rhIL-2) is a key cytokine for cancer immunotherapy, but it has the propensity to express as insoluble inclusion bodies in Escherichia coli as it is hydrophobic. In this study, the soluble expression and purification of rhIL-2 was maximized in a His-MBP fusion system in the E. coli Origami B (DE3) host strain that supports disulfide bond formation. The fusion protein was overexpressed in a soluble state, processed using immobilized metal ion affinity chromatography (IMAC-Ni) and His-tagged TEV protease cleavage. Ni-NTA flow-through chromatography yielded rhIL-2 to >95% homogeneity. High-performance size exclusion chromatography (HP-SEC) confirmed the presence of monomeric and aggregated states, while bioactivity assays demonstrated the biologically active nature of the purified rhIL-2 with an EC50 value (3.13 ng/mL) comparable to the reference standard (2.54 ng/mL). The current approach offers an economical and viable method for the production of biologically active rhIL-2, which can be employed in research and clinical immunotherapy.