肠道病毒71型体外感染人树突状细胞后启动免疫应答反应的研究

In vitro experimental studies on immune responses to human dendritic cells infected with enterovirus71

目的研究肠道病毒71型（EV71）体外感染人树突状细胞（DCs）后启动免疫应答反应的机制，为探讨EV71感染及宿主免疫应答提供理论依据。方法健康成人外周血单核细胞诱导衍生获得DCs，流式细胞术检测病毒感染前后DCs表面分子，PCR芯片分析DCs感染EV712h和8h后CD分子及细胞因子类基因差异表达，Luminex液相芯片技术检测感染组细胞上清液中细胞因子含量，混合淋巴细胞反应（MLR）检测病毒感染后的DCs对初始T细胞的刺激活性。结果EV71感染刺激后DCs的CD80和CD83表达率分别提高了8．2％和35．4％。PCR芯片显示EV71感染2h和8h后CD80、CD83、IL-1α、IL-6和ICAM-1基因表达显著上调2．08～5．49倍，而IL-18则下调5．12倍。与对照组相比，EV71感染Des组细胞上清液中IL-6和IL-12的含量明显升高（P〈0．05）。而MLR未观察到EV71感染的DCs刺激初始T细胞增殖现象。结论EV71感染能增加DCs活力，延长其存活时间，促使其活化、成熟并分泌细胞因子，启动宿主细胞相应的免疫应答。

Objective To study the mechanism of immune responses in enterovirus 71 （EV71）- infected human dendritic cells （DCs） in vitro and provide theoretical basis for EV71 infection and host immune response. Methods Peripheral blood mononuclear cells were purified from the healthy adult peripheral blood and immature DCs were generated from monocytes by culturing in medium containing cytokines. DCs surface markers wereanalyzed by flow cytometry before and after EV71 infection. PCR array was employed to detect the gene expressions of CD molecules and cytokines from EV71-infected DCs at 2 and 8 h postinfection, respectively. The cytokines of EV71-infected DCs in culture supernatants were measured by Luminex liquiehip. In addition, the activity of navie T-cell by EV71-infected DCs was examined by mixed-lymphocyte reaction. Results EV71 infection increased the expressing percentages of CD80 and CD83 on DCs by 8.2% and 35.4% , respectively. PCR array revealed that the expressions of CD80, CD83, IL-lct,IL-6, and ICAM-1 genes were significantly upregulated 2.08 to 5.49-fold at 2 h and 8 h postinfection, while IL-18 gene was downregulated 5. 12-fold. Compared with control, the levels of IL-6 and IL-12 were distinctly elevated in EV71-infected DCs （P 〈 0. 05）. However, the proliferation of navie T-cell stimulated by EV71-infected DCs weren＇t observed by MLR. Conclusion It indicates that EV71 infection not only can increase the viability, the survival time and activation of DCs, but also can significantly increase releases of IL-6 and IL-12 in DCs, which initiate immune response in host cells.