Molecular study of mouse viral resistance mechanisms

描述（由申请人提供）：该提议基于最近的实验结果，该实验结果使用了成对的同源和转基因小鼠品系，其具有对鼠CMV感染的细胞的不同的缺失自身MHC-I Dk识别，以检查NK细胞在病毒感染的动物中的作用。该研究项目的广泛长期目标旨在了解NK细胞中的抑制性受体信号传导以及对NK细胞快速响应和杀死病毒感染细胞的能力的影响。该研究提案提出的一个有趣的问题是，NK抑制性受体对病毒感染的识别是否只是允许NK细胞中的激活受体信号，或者直接激活NK细胞中有效的效应子应答和病毒抗性所需的信号级联。这种区别是重要的，因为NK细胞对其他免疫细胞具有深远的影响，包括引发病毒特异性T细胞效应器。研究提案中的一个指导性假设是，病毒感染的NK抑制性受体识别传递了一个有效的信号，该信号允许或“激活”快速NK反应，以立即提供针对进一步感染的保护，并开始培养引发适应性免疫反应所需的其他免疫细胞。提出了三个具体目标：目标1。将确定抑制性受体信号传导和病毒感染的缺失自身MHC I类识别在NK细胞介导的抗性和适应性病毒免疫增强中的作用。我们将检验抑制性受体是Ly 49 G缺失小鼠中MCMV感染细胞的缺失自身MHC-IDk识别所需的假设。拟议的实验将检查Ly 49 G2缺陷对先天性病毒抗性、病毒特异性T细胞效应子的引发、病毒持久性和死亡率的影响。目标2.将评估抑制性受体信号传导和病毒感染靶细胞的自我识别缺失对NK细胞近膜信号传导事件的影响，并确定关键的NK细胞表达差异，这可能与先天性病毒耐药性有因果关系。我们将研究病毒感染背景下的Ly 49 G2抑制性受体信号传导，以及MHC-I Dk感染细胞的自我识别缺失允许或激活以NK细胞中明显的生化变化为标志的有效信号以促进NK细胞反应性的假设。目标3。将对增强NK细胞上抑制性受体表达和NK细胞介导的病毒抗性的非MHC基因座进行精细的遗传作图、鉴定和表征。我们将检验Ly 49 G2受体表达和MCMV抗性的修饰剂决定NK细胞对感染的反应、它们识别感染细胞的能力以及因此它们对适应性免疫的影响的假设。NK细胞对人类健康至关重要。它们可以防止恶性肿瘤和病毒感染。NK细胞识别并响应许多不同类型的病毒。然而，一些病毒能够逃避NK细胞检测（例如疱疹病毒），而其他病毒（例如HIV）能够比NK细胞更持久，更机智或击败NK细胞。因此，了解NK细胞如何识别体内病毒感染的细胞至关重要。该领域的最新进展具有显著的前景，因为我们现在知道NK细胞可以使用直接识别病毒感染细胞的活化受体，因此充分靶向NK细胞杀伤。然而，具有活化受体的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响应病毒感染。不幸的是，一个建立的模型来研究病毒感染中NK抑制受体的作用是不可用的。我们的实验室已经成功地产生了这样一个创新的模型，这项研究计划将使用它来研究NK细胞抑制性受体的影响及其对抗病毒NK细胞效应功能的贡献。

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.