National Institute of Virology Kerala Unit, Medical College Hospital Complex, Vandanam, Alappuzha, Kerala 688005, India.
BMC Infect Dis. 2012 May 29;12:125. doi: 10.1186/1471-2334-12-125.
The susceptibility of mice and humans to Chandipura virus infection is age-dependent. Upon experimental infection, mice secrete significant amounts of proinflammatory cytokines. Similarly, children who recover from natural infection with the virus show significant amounts of TNF-α production, suggesting that innate immunity plays a major role in the response to Chandipura virus. Toll-like receptors (TLR) are key host molecules involved in innate immune responses in infections. Therefore, the aim of this study was to examine the role of TLR in the response to Chandipura virus infection.
The mouse monocyte-macrophage cell line, RAW 264.7, and C3H/HeJ mice were used as models. Micro array techniques were used to identify the type of TLR involved in the response to infection. The results were validated by examining TLR expression using flow cytometry and by measuring the levels of proinflammatory cytokines and nitric oxide (NO) in the culture supernatants using bead assays and the Griess method, respectively. The pathogenic role of Toll-like receptor 4 (TLR4) was studied in a TLR4 mutant strain of mice -C3H/HeJ and the results compared with those from wild-type mice- C3H/CaJ. The pathogenic effects of NO were studied by treating experimentally infected mice with the NO inhibitor, aminoguanidine (AG).
The micro array results showed that TLR4 was regulated after Chandipura virus infection. At high multiplicities of infection (10 MOI), RAW cells up- regulated cell surface expression of TLR4 and secreted significant amounts of TNF-α, MCP-1, IL-10 and IL-12 and NO. The survival rate of C3H/HeJ mice was higher than those of wild-type C3H/CaJ mice. The survived C3H/HeJ mice secreted significant quantity of MCP-1 and IFN-γ cytokines and cleared virus from brain. Similarly, the survival rate of AG-treated mice was higher than those of the untreated controls.
Chandipura virus regulates TLR4, which leads to the secretion of proinflammatory cytokines and NO by infected RAW cells. Difference in survival rate in TLR4 mutant mice and nitric oxide inhibitor treated mice, confirmed the role of these molecules in disease pathogenesis. The result is significant in clinical management and designing antiviral intervention for Chandipura virus infection.
小鼠和人类对 Chandipura 病毒感染的易感性与年龄有关。在实验感染后，小鼠会分泌大量促炎细胞因子。同样，从自然感染该病毒中恢复的儿童也会产生大量 TNF-α，这表明先天免疫在 Chandipura 病毒的反应中起着重要作用。 Toll 样受体 (TLR) 是感染中固有免疫反应的关键宿主分子。因此，本研究旨在研究 TLR 在 Chandipura 病毒感染反应中的作用。
使用小鼠单核巨噬细胞系 RAW 264.7 和 C3H/HeJ 小鼠作为模型。使用微阵列技术鉴定参与感染反应的 TLR 类型。通过流式细胞术检查 TLR 表达，通过珠试验和 Griess 法分别测量培养上清液中促炎细胞因子和一氧化氮 (NO) 的水平来验证结果。在 TLR4 突变株小鼠 -C3H/HeJ 中研究 Toll 样受体 4 (TLR4) 的致病作用，并将结果与野生型小鼠 -C3H/CaJ 进行比较。通过用 NO 抑制剂氨基胍 (AG) 处理实验感染的小鼠来研究 NO 的致病作用。
微阵列结果表明，Chandipura 病毒感染后 TLR4 受到调节。在高感染复数（10 MOI）下，RAW 细胞上调 TLR4 的细胞表面表达并分泌大量 TNF-α、MCP-1、IL-10 和 IL-12 以及 NO。C3H/HeJ 小鼠的存活率高于野生型 C3H/CaJ 小鼠。存活的 C3H/HeJ 小鼠分泌大量 MCP-1 和 IFN-γ 细胞因子，并从大脑中清除病毒。同样，AG 处理组小鼠的存活率高于未处理对照组。
Chandipura 病毒调节 TLR4，导致受感染的 RAW 细胞分泌促炎细胞因子和 NO。TLR4 突变小鼠和一氧化氮抑制剂治疗小鼠存活率的差异，证实了这些分子在疾病发病机制中的作用。这一结果在 Chandipura 病毒感染的临床管理和抗病毒干预设计中具有重要意义。
