Inhibition of the Interferon Response by West Nile Virus

描述(申请人提供)：我们对西尼罗河病毒(WNV)先天免疫反应的研究发现，西尼罗河病毒的复制抑制了干扰素用来诱导细胞抗病毒程序的信号转导途径。结果表明，一个或多个病毒非结构(NS)蛋白抑制JAK1和TYK2的磷酸化和激活，这是建立对干扰素的抗病毒状态所必需的。建议的研究计划的目的是通过三个特定的目的来研究这种对干扰素反应的抑制的机制。 在第一个目标中，我们将使用遗传方法来鉴定病毒蛋白(S)，这些蛋白负责在西尼罗河病毒感染的细胞中观察到IFNA反应的抑制。我们的目标是鉴定已经失去抑制干扰素反应能力的具有复制能力的西尼罗河病毒突变体。通过第二个目标中描述的生化方法，我们将研究宿主与病毒之间的相互作用，这些相互作用在抑制西尼罗河病毒感染细胞中的干扰素信号转导途径中发挥作用。具体地说，我们将确定病毒蛋白是通过与IFNA受体复合体结合直接抑制干扰素反应，还是通过激活细胞拮抗剂间接起作用，如蛋白质酪氨酸磷酸酶或其他已知的干扰素反应负调控因子。实验旨在确定为病毒拮抗剂提供靶点的细胞因素。第三个目标，我们将调查宿主先天免疫反应和病毒成分之间的关系如何影响西尼罗河病毒感染的结局。在允许干扰素诱导基因有条件表达的系统的帮助下，我们将研究细胞抗病毒机制如何抑制西尼罗河病毒的复制，并确定构成针对西尼罗河病毒的固有抗病毒程序的细胞基因的性质。 西尼罗河病毒已成为一种具有全球意义的病原体，可导致瘫痪、脑膜脑炎和死亡。原发西尼罗河病毒感染尚不能通过接种疫苗来预防，到目前为止，还没有预防感染的严重后果的治疗方法，特别是影响老年人的感染。这里提出的研究将提供更好的了解控制西尼罗河病毒复制和致病的宿主-病毒相互作用。这一新信息可以作为开发有效的抗病毒疗法的基础。

DESCRIPTION (provided by applicant): Our investigations of the innate immune response against West Nile virus (WNV), led to the discovery that WNV replication inhibits the signal transduction pathways used by interferons to induce cellular antiviral programs. The results indicated that one or more viral non-structural (NS) proteins inhibit the phosphorylation and activation of the Janus kinases JAK1 and Tyk2, which is required to establish an antiviral state in response to IFN. The purpose of the proposed research program is to investigate the mechanism responsible for this inhibition of the IFN response through three specific aims. In the first aim, we will use a genetic approach to identify the viral protein(s) that are responsible for the observed inhibition of the IFNa response in WNV infected cells. Our goal is to identify replication competent WNV mutants that have lost the ability to inhibit the IFN response. With a biochemical approach described in the second aim, we will investigate the host-virus interactions that play a role in the inhibition of the IFN signal transduction pathway in WNV infected cells. Specifically, we will determine if viral proteins inhibit the IFN response directly through binding to the IFNa receptor complex or if they operate indirectly by activating a cellular antagonist, such as a protein tyrosine phosphatase or other known negative regulators of the IFN response. Experiments were designed to identify the cellular factors that provide targets for the viral antagonists. With the third aim, we will investigate how the relationship between the host innate immune response and viral components influences the outcome of WNV infections. With the help of a system permitting the conditional expression of IFN-induced genes, we will investigate how cellular antiviral mechanisms inhibit WNV replication and determine the nature of the cellular genes that constitute the innate antiviral program against WNV. WNV has emerged as a pathogen of global significance that can cause paralysis, meningo-encephalitis, and death. Primary WNV infections cannot yet be prevented by vaccination and, so far, treatments to prevent the serious consequences of infections that affect particularly the elderly are not yet available. The studies proposed here will provide a better understanding of host-virus interactions that control WNV replication and pathogenesis. This new information can be used as the basis for the development of effective antiviral therapies.