Molecular study of mouse viral resistance mechanisms

描述(申请人提供)：这项建议是基于最近的实验结果，配对的同源和转基因小鼠具有不同的MHC-I DK识别小鼠CMV感染细胞的作用，以检查NK细胞在病毒感染动物中的作用。该研究项目的长期目标是了解NK细胞中的抑制性受体信号及其对NK细胞快速反应和杀死病毒感染细胞能力的影响。该研究提案提出的一个有趣的问题是，病毒感染的NK抑制受体识别是简单地允许激活NK细胞中的受体信号，还是直接激活NK细胞中有效的效应器反应和病毒耐药性所需的信号级联。这一区别很重要，因为NK细胞对其他免疫细胞有深远的影响，包括启动病毒特异性T细胞效应器。研究建议中的一个指导性假设是，对病毒感染的NK抑制受体识别传递了一个强有力的信号，允许或‘激活’快速的NK反应，立即提供保护，防止进一步感染，并开始培养启动适应性免疫反应所需的其他免疫细胞。目的1.确定抑制性受体信号转导和缺失自身MHC-I类分子识别病毒感染在NK细胞介导的抵抗和增强适应性病毒免疫中的作用。我们将测试这一假设，即在Ly49G基因缺失的小鼠中，MCMV感染细胞的缺失自身MHC-I DK识别需要抑制受体。拟议的实验将检查Ly49G2缺陷对先天病毒抵抗力、病毒特异性T细胞效应器的启动、病毒持久性和死亡率的影响。目的2.评估病毒感染靶细胞的受体抑制信号和缺失自我识别对NK细胞膜近端信号事件的影响，以确定NK细胞表达的关键差异，这些差异可能与病毒先天抵抗有关。我们将在病毒感染的背景下研究Ly49G2抑制受体信号转导，并假设MHC-I DK感染细胞的缺失自我识别允许或激活以NK细胞明显的生化变化为标志的有效信号，以促进NK细胞的反应性。目的3.对增强NK细胞抑制性受体表达和NK细胞介导的病毒抵抗力的非MHC基因座进行精细的遗传定位、鉴定和鉴定。我们将检验这一假设，即Ly49G2受体表达和MCMV抗性的修饰物决定了NK细胞如何响应感染，它们识别感染细胞的能力，以及它们对获得性免疫的影响。相关性NK细胞对人类健康至关重要。它们可以预防恶性肿瘤和病毒感染。NK细胞识别并对许多不同类型的病毒做出反应。然而，一些病毒能够躲避NK细胞的检测(例如疱疹病毒)，而其他病毒(例如HIV)能够比NK细胞存活、智胜或击败NK细胞。因此，了解NK细胞如何识别体内感染病毒的细胞是至关重要的。这一领域的最新进展具有显著的前景，因为我们现在知道NK细胞可以使用激活受体直接识别病毒感染的细胞，从而充分靶向NK细胞的杀伤。然而，带有激活受体的NK细胞不能抑制所有病毒感染。尽管如此，NK细胞也使用抑制性受体来识别和应对病毒感染。不幸的是，之前还没有一个已建立的模型来研究NK抑制受体在病毒感染中的作用。我们的实验室已经成功地建立了这样一个创新的模型，本研究计划将利用它来研究NK细胞抑制受体的影响及其在抗病毒NK细胞效应功能中的作用。

DESCRIPTION (provided by applicant): This proposal is based on recent experimental results with paired congenic and transgenic strains of mice with divergent missing-self MHC-I Dk recognition of murine CMV infected cells to examine the role of NK cells in virus infected animals. The broad long-term objective for the research project seeks to understand inhibitory receptor signaling in NK cells and the impact on the NK cell's ability to rapidly respond to and kill virus infected cells. An interesting question raised by the research proposal is whether NK inhibitory receptor recognition of virus infection simply permits activation receptor signals in NK cells or directly activates a signal cascade in NK cells needed in efficient effector responses and viral resistance. This distinction is important since NK cells have a profound effect on other immune cells, including the priming of virus-specific T cell effectors. A guiding hypothesis in the research proposal is that NK inhibitory receptor recognition of virus infection delivers a potent signal which permits or 'activates' rapid NK responses to immediately provide protection against further infection and begin to cultivate other immune cells needed to prime adaptive immune responses. Three specific aims are proposed: Aim 1. will determine the effect of inhibitory receptor signaling and missing-self MHC class I recognition of virus infection in NK cell-mediated resistance and enhancement of adaptive viral immunity. We will test the hypothesis that an inhibitory receptor is required in missing-self MHC-I Dk recognition of MCMV infected cells in Ly49G-null mice. Proposed experiments will examine the effect of Ly49G2 deficiency on innate virus resistance, priming of virus-specific T cell effectors, viral persistence and mortality. Aim 2. will assess the effect of inhibitory receptor signaling and missing-self recognition of virus infected target cells on membrane proximal signaling events in NK cells and identify key NK cell expression differences, which may be causally linked with innate virus resistance. We will investigate Ly49G2 inhibitory receptor signaling in the context of virus infection and the hypothesis that missing-self recognition of MHC-I Dk infected cells permits or activates a potent signal, marked by distinct biochemical changes in NK cells, to promote NK cell responsiveness. Aim 3. will perform refined genetic mapping, identification and characterization of non-MHC loci that enhance inhibitory receptor expression on NK cells and NK cell-mediated virus resistance. We will test the hypothesis that modifiers of Ly49G2 receptor expression and MCMV resistance determine how NK cells respond to infection, their capacity to recognize infected cells and consequently their impact on adaptive immunity. Relevance NK cells are vital to human health. They protect against malignancy and virus infection. NK cells recognize and respond to many different types of viruses. However, some viruses are able to evade NK cell detection (e.g. herpesviruses) and others (e.g. HIV) are able to outlast, outwit or defeat NK cells. Thus, it is critical to understand how NK cells recognize virus infected cells in the body. Recent advances in this field have remarkable promise since we know now that NK cells can use activation receptors that directly recognize virus infected cells and therefore target NK cell killing adequately. However, NK cells with activation receptors cannot restrain all virus infections. Despite this, NK cells use inhibitory receptors also to recognize and respond to viral infection. Unfortunately, an established model to investigate the effect of NK inhibitory receptors in viral infections was not available before. Our laboratory has succeeded in generating such an innovative model and this research proposal will use it to investigate the impact of NK cell inhibitory receptors and their contribution to antiviral NK cell effector functions.