目的  构建重组人白细胞介素24（recombinant human interleukin 24， rhIL-24）的表达载体并在大肠杆菌中表达，体外评估rhIL-24的生物学活性。方法  用基因工程方法构建rhIL-24表达载体并在大肠杆菌中表达rhIL-24。表达的重组蛋白经层析法纯化后，分别用MTT法和蛋白印迹法检测rhIL-24对肿瘤细胞生长的影响和对内源性IL-24的诱导，用实时PCR检测不同肿瘤细胞与rhIL-24共孵育后细胞内的胱天蛋白酶3（caspase 3）mRNA变化。结果  rhIL-24能在大肠杆菌中高效表达，并能明显抑制多种肿瘤细胞生长。rhIL-24能诱导正常MRC-5细胞和多种肿瘤细胞产生内源性IL-24，并能改变肿瘤细胞的胱天蛋白酶3水平。  结论　rhIL-24能在大肠杆菌中高效表达，且具有生物学活性。

Objective  To construct an expression vector of recombinant human interleukin-24(rhIL-24) and express it in E.coli, and evaluate the biological activity in vitro. Methods  An expression vector of rhIL-24 was constructed by genetic engineering and rhIL-24 was expressed in E.coli. After purification of rhIL-24 by chromatography, MTT assay was used to determine the effect of rhIL-24 on the growth of tumor cells and the Western blotting was used to determine the induction of endogenous IL-24 by rhIL-24. rhIL-24 was coincubated with different tumor cells, and real-time PCR was used to determine the change of caspase 3 mRNA. Results  rhIL-24 was highly expressed in E.coli, and the growth of tumor cells was inhibited significantly by rhIL-24. rhIL-24 could induce normal MRC-5 cell and tumor cells to produce endogenous IL-24, and change caspase 3 level of tumor cells. Conclusion  rhIL-24 is highly expressed in E.coli and has biological activity.