Expression, purification, and characterization of a functional mutant recombinant human interleukin-2.

In the current study, a mutant recombinant human interleukin-2 (MhIL-2) was generated using site-directed mutagenesis. The bacteria transformed with plasmid pET15b-MhIL-2 were cultured in LB medium containing 0.6mM IPTG for 8 hours at 27°C. Approximately 90% of His-MhIL-2 was efficiently expressed in soluble form. Purification efficiency was optimized using a number of strategies, including nickel ion chelating chromatography, desalting chromatography, thrombin cleavage and Superdex 75 gel filtration chromatography. The final product had >95% purity. PBMCs, CD4+ and CD8+ T cell proliferation assays revealed that one such mutant has identical functional property to the wild-type hIL-2. In summary, we generated a mutant hIL-2 that is functionally identical to wild-type hIL-2.