Refolding and high-level expression study onhuman interferon-γ in E.coli

Monocytes were obtained from healthy volunteers and total RNA was prepared from these cells after stimulation with LPS. Human interferonγ (γIFN) cDNA was amplified with RTPCR and cloned into plasmid vector. DNA sequencing showed that the amplified γIFN gene has two polimorphic sites. Highlevel expression of γIFN was achieved using temperaturecontroled E.coli expression system. The expressed protein is about 55% of total cellular protein after induction. Pure recombinant γIFN protein was prepared with simultaneous refolding and purification using high performance hydrophobic chromatography after fermentation of E.coli. The purified γIFN protein has comparable activity as natural product. 