ABSTRACT
A DNA fragment encoding recombinant human interleukin 11 (hrIL-11) was obtained by PCR from previously constructed pET24a-hrIL-11 plasmid. Then pET21a-hrIL-11 expression vector was constructed routinely and transformed into BL-21(DE3). By the induction of Isopropyl-1-thio-beta-D-galactoside (IPTG), hrIL-11 protein was highly expressed at about 20% of the total bacterial proteins and was identified by Western blot. After purification with Ni-NTA affinity chromatography and refolding with renaturation buffer, the purity of the target hrIL-11 protein reached 95% and its biology activity was 1 x 10(6) IU/mg, determined by stimulating the proliferation of T1165, which facilitates further researches into effects of IL-11 on platelet proliferation and other function.