小鼠白细胞介素17A的原核表达及对RAW264.7细胞分泌炎症因子的影响

Prokaryotic expression of mouse interleukin 17A and its ability of stimulating RAW264.7 cell inflammatory factors expression

目的 在大肠杆菌中高效表达与纯化小鼠白细胞介素17A（mIL-17A）,并研究其对巨噬细胞分泌炎症因子的影响.方法 以活化的脾细胞为模板,通过RT-PCR法扩增小鼠IL-17a基因的编码序列,构建重组表达质粒pET28a/mIL-17a,并在大肠杆菌（E.coli）中诱导表达,经亲和层析获得纯化的mIL-17A蛋白.以mIL-17A蛋白刺激体外培养的鼠巨噬细胞RAW264.7,72 h后应用realtime PCR法分析IL-6、巨噬细胞炎症蛋白1（Ccl3）、巨噬细胞炎症蛋白2（Cxcl3）、β防御素2（defensinβ2）的mRNA表达量,并用ELISA法检测培养上清中Ccl3、Cxcl3、IFN-γ、IL-4及IL-6的蛋白质表达水平.结果 在E.coli中成功高效表达了有生物活性的IL-17A蛋白,可促进体外培养的RAW264.7细胞IL-6、Cxcl3、defensin β2 mRNA的表达,并能促进Ccl3、Cxcl3、IFN-γ、IL-4以及IL-6蛋白的表达.结论 成功表达并制备了具备生物学活性的mIL-17A,该蛋白具有刺激巨噬细胞表达趋化因子、防御素及细胞因子的能力.

Objective To express and purify mouse interleukin 17A（mIL-17A） in E. coli and to analyze its ability of stimulating macrophage inflammatory factors expression. Methods The coding gene of mouse mIL-17A mature protein was amplified from mouse spleen cells by RT-PCR. PCR product was cloned into the prokaryotic expressing vector pET28a, and the resulting recombinant plasmid pET28a/mIL-17a was then transformed into the host E. coli strain BL21（DE3） for expression. The mIL-17A protein was identified by SDS-PAGE and Western blot. The recombinant protein was purified by the Ni-NTA affinity chromatography, and was further tested on the stimulation of cytokine and chemokine of RAW264.7 cells by ELISA and real-time quantity PCR in vitro. Results The mIL-17A with bioactivity was over-expressed and purified successfully, and the results of real-time PCR and ELISA showed that recombinant mIL-17A stimulated macrophage mRNA upregulation of IL-6, defensin β2 and Cxcl3 and secretion of defensin β2, Ccl3, Cxcl3,IFN-γ, IL-6 and IL-4. Interestingly, these effects could be blocked by the addition of anti-IL-17A neutralizing antibody partly. After treatment with mIL-17, 74. 87-fold of defensin β2 mRNA expression was increased comparing with that of untreated cells（ P 〈0.01 ）, while blocking with anti-IL-17A antibody the increase was only 5.4-fold（P 〈 0.01 ）. Conclusion The recombinant mIL-17A has a strong stimulation on secretion of cytokine and chemokine of macrophage, that maybe result to the enhancement of anti-infection ability of macrophage.