Efficient Expression and Purification Technique of a Mutant of Human Interleukin 2
一种白细胞介素2基因变构体的高效表达与纯化工艺

Mutants of recombinant hIL-2 (rhIL-2), generated by using site-directed mutagenesis strategy, can increase anti-tumor activity and decrease toxicity. We have used site-directed mutagenesis of hIL-2 to generate a mutant of hIL-2(MhIL-2) in which Asn88 was substituted by Arg88. To reduce the undesirable formation of inclusion body and maximize the yield of soluble MhIL-2 fusion protein, we adapted a protocol for the expression of soluble MhIL-2 fusion protein. Our results have indicated that soluble form of the MhIL-2 fusion protein is expressed from E. coli.. Moreover, it also has facilitated purification of the MhIL-2. SDS-PAGE analysis revealed that the MhIL-2 protein was efficiently purified to 95% purity by the combination of nickel ion Chelating column chromatography, Desalting column chromatography, thrombin cleavage and Superdex 75 gel filtration column chromatography. Proliferation assay of T lymphocyte of purified MhIL-2 showed that the biological activity of MhIL-2 was higher than that of standard hIL-2 in vitro. This work not only describes an efficient preparation strategy of MhIL-2, but also introduces a highly active MhIL-2 that may have important clinical applicability.