Interleukin 18：High Level Expression in E.coli，Purification and Renaturation of the
Recombinant Protein
PEI Dong-Sheng, HU Shu-Qun, ZHAO Hui-Ren*
( Research Center for Biochemistry and Molecular Biology, Xuzhou Medical
College, Xuzhou 221002, China )
Abstract Using the total
RNA extracted from mitogen-stimulated human peripheral blood mononuclear cells
(PBMC) as template, the cDNA of interleukin 18 was amplified by RT-PCR. The
cDNA was subsequently cloned into the expression vector pJW2 and sequenced. The
recombinant human IL-18 (rhIL-18) was expressed efficiently in inclusion bodies
in E.coli with the yield accounting for 20% total bacteria proteins.
The inclusion bodies were washed with 2 mol/L urea and rhIL-18 was further
purified using Sephadex G-100 column chromatography in 8 mol/L urea. After
purification, the purity of rhIL-18 was greater than 90% as judged by SDS-PAGE.
The purified rhIL-18 showed significant and dose-dependent IFN-γ-inducing
activity in human PBMC, in the presence of 0.5 mg/L Con A.
Key words interleukin 18； expression； purification； renaturation
*Corresponding author： Tel, 86-516-5748423； e-mail, [email protected]