School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, PR China.
BMC Infect Dis. 2012 Sep 21;12:224. doi: 10.1186/1471-2334-12-224.
The levels of proinflammatory cytokine or chemokine in blood and cerebrospinal fluid are thought to be one of predictors for clinical severity of enterovirus 71 (EV71) infection, yet the cellular sources or signalling mechanism remain undefined. Here, we focused on the response of human primary monocyte-derived macrophages (MDMs) to EV71 virus and its possible mechanisms.
Human primary MDMs were infected by EV71 virus in vitro. Infectivity and viral replication were assayed, and cytokine responses were determined by Cytometric Bead Array(CBA) analysis. The relative changes of Toll-like receptors, retinoic acid-inducible gene I (RIG-I) and melamoma differentiation associated gene 5 (MDA5) mRNA expression were detected by real-time RT-PCR.
Effective infection and viral replication were detected in EV71-infected MDMs. The titters of progeny virus released from EV71-infected MDMs gradually increased from 6-h to 48-h point of infection (POI.). Proinflammatory cytokines: IL-1, IL-6, TNF-α but not IFN-α and γ were induced in MDMs by EV71. EV71 infection significantly increased the release of IL-8, IP-10 and RANTES at 12-h or 24-h POI. Upregulation of TLR2, TLR7 and TLR8 mRNA expression rather than TLR3, TLR4, TLR6, TLR9, TLR10, RIG-I, MDA5 were found at different time points in EV71-infected MDMs.
Our findings suggested that macrophages are not only the important target cells but also the effectors during EV71 infection, and they may play an important role in the pathogenesis of EV71 infection. And the proinflammatory cytokine and chemokine responses in EV71-infected MDMs may be mediated by the activation of differential pattern of TLRs.
人们认为血液和脑脊液中促炎细胞因子或趋化因子的水平是肠道病毒 71（EV71）感染临床严重程度的预测因素之一，但细胞来源或信号机制仍未确定。在这里，我们专注于人类原代单核细胞衍生的巨噬细胞（MDM）对 EV71 病毒的反应及其可能的机制。
在体外用人原发性单核细胞衍生的巨噬细胞（MDM）感染 EV71 病毒。通过细胞因子珠阵列（CBA）分析测定感染性和病毒复制，测定细胞因子反应。通过实时 RT-PCR 检测 Toll 样受体、视黄酸诱导基因 I（RIG-I）和黑色素瘤分化相关基因 5（MDA5）mRNA 表达的相对变化。
在 EV71 感染的 MDM 中检测到有效感染和病毒复制。从 EV71 感染的 MDM 中释放的后代病毒的滴度从 6 小时到 48 小时感染点（POI）逐渐增加。EV71 在 MDM 中诱导促炎细胞因子：IL-1、IL-6、TNF-α，但不诱导 IFN-α 和 γ。EV71 感染在 12 小时或 24 小时 POI 时显著增加了 IL-8、IP-10 和 RANTES 的释放。在 EV71 感染的 MDM 中，不同时间点 TLR2、TLR7 和 TLR8 mRNA 表达上调，而 TLR3、TLR4、TLR6、TLR9、TLR10、RIG-I 和 MDA5 则下调。
我们的研究结果表明，巨噬细胞不仅是 EV71 感染的重要靶细胞，也是效应细胞，它们可能在 EV71 感染的发病机制中发挥重要作用。EV71 感染的 MDM 中促炎细胞因子和趋化因子的反应可能是通过激活不同模式的 TLR 介导的。
