Zhang Junjie, Zhu Lining, Feng Pinghui
Department of Microbiology and Immunology, Keck School of Medicine, University of Southern California.
Department of Microbiology and Immunology, Keck School of Medicine, University of Southern California;
J Vis Exp. 2014 Mar 2(85):51078. doi: 10.3791/51078.
In response to a viral infection, the host innate immune response is activated to up-regulate gene expression and production of antiviral cytokines. Conversely, viruses have evolved intricate strategies to evade and exploit host immune signaling for survival and propagation. Viral immune evasion, entailing host defense and viral evasion, provides one of the most fascinating and dynamic interfaces to discern the host-virus interaction. These studies advance our understanding in innate immune regulation and pave our way to develop novel antiviral therapies. Murine γHV68 is a natural pathogen of murine rodents. γHV68 infection of mice provides a tractable small animal model to examine the antiviral response to human KSHV and EBV of which perturbation of in vivo virus-host interactions is not applicable. Here we describe a protocol to determine the antiviral cytokine production. This protocol can be adapted to other viruses and signaling pathways. Recently, we have discovered that γHV68 hijacks MAVS and IKKβ, key innate immune signaling components downstream of the cytosolic RIG-I and MDA5, to abrogate NFΚB activation and antiviral cytokine production. Specifically, γHV68 infection activates IKKβ and that activated IKKβ phosphorylates RelA to accelerate RelA degradation. As such, γHV68 efficiently uncouples NFΚB activation from its upstream activated IKKβ, negating antiviral cytokine gene expression. This study elucidates an intricate strategy whereby the upstream innate immune activation is intercepted by a viral pathogen to nullify the immediate downstream transcriptional activation and evade antiviral cytokine production.
针对病毒感染，宿主的固有免疫反应被激活，以上调基因表达并产生抗病毒细胞因子。相反，病毒已经进化出复杂的策略来逃避和利用宿主免疫信号以实现生存和繁殖。病毒免疫逃逸涉及宿主防御和病毒逃避，为识别宿主 - 病毒相互作用提供了最引人入胜且动态变化的界面之一。这些研究增进了我们对固有免疫调节的理解，并为开发新型抗病毒疗法铺平了道路。鼠γ疱疹病毒68（Murine γHV68）是鼠类啮齿动物的天然病原体。小鼠感染γHV68提供了一个易于处理的小动物模型，用于研究对人类卡波西肉瘤相关疱疹病毒（KSHV）和爱泼斯坦 - 巴尔病毒（EBV）的抗病毒反应，而体内病毒 - 宿主相互作用的干扰在此并不适用。在此，我们描述一种确定抗病毒细胞因子产生的方案。该方案可适用于其他病毒和信号通路。最近，我们发现γHV68劫持线粒体抗病毒信号蛋白（MAVS）和IκB激酶β（IKKβ），它们是胞质视黄酸诱导基因I（RIG - I）和黑色素瘤分化相关蛋白5（MDA5）下游关键的固有免疫信号成分，以消除核因子κB（NFΚB）的激活和抗病毒细胞因子的产生。具体而言，γHV68感染激活IKKβ，激活的IKKβ使RelA磷酸化以加速RelA降解。因此，γHV68有效地将NFΚB激活与其上游激活的IKKβ解偶联，使抗病毒细胞因子基因表达无效。这项研究阐明了一种复杂的策略，即病毒病原体拦截上游固有免疫激活，使直接下游的转录激活无效，并逃避抗病毒细胞因子的产生。
