Innate and Adaptive Immune Responses in the Virus-Infected Heart

描述（由申请人提供）：柯萨奇病毒是急性心肌炎最常见的感染原因，急性心肌炎是一种导致大量人类发病率和死亡率的疾病。即使在病毒（明显地）被清除后，低度炎症仍可能继续，最终导致扩张性心肌病的严重后果。人们普遍认为，先天和适应性宿主免疫反应既有助于病毒控制，也有助于（免疫病理性）心脏病。然而，我们对柯萨奇病毒诱导的免疫反应的了解是初步的。在本提案中，使用现有的和新的柯萨奇病毒B3 （CVB3）感染小鼠模型，我们将评估I型干扰素（T1IFN）对急性和持续性CVB3感染的心内作用，我们将使用一套独特的试剂，在我的实验室开发，以评估感染小鼠心脏中的cb3特异性T细胞反应。有3个具体目标：T1IFN在心脏中的作用是有争议的。一些已发表的研究表明，这些先天细胞因子可能会清除心脏中的病毒，但其他研究表明，它们在受感染的心脏中没有任何作用。我们将交叉两种现有的小鼠品系来开发一种新的小鼠模型，在这种模型中，心肌细胞上的T1IFN受体的表达可以随意消融。这些小鼠将使我们能够解决上述争议，并确定T1IFN是否负责限制病毒在急性感染心脏中的传播。此外，通过在持续感染期间去除该受体，我们将能够确定维持持续状态是否需要T1IFN。2. 尽管经过多年的研究，我们对cvb特异性T细胞反应的了解仍然很少。为了解决这一缺陷，我的实验室已经生成了多种独特的试剂，包括表达具有良好特征的CD4+和CD8+ T细胞表位的重组CVB，以及针对这些表位特异性的遗传标记T细胞。我们将利用我们的试剂来研究急性心肌炎过程中CVB特异性CD4+和CD8+ T细胞在心脏中的浸润动力学，并将确定这种T细胞浸润受T1IFN调节的程度。3. 我们还将使用上述试剂来绘制急性和持续性感染期间心脏内CVB3抗原的表达。抗原在哪些心脏细胞中表达？抗原特异性CD4+和CD8+ T细胞在感染后的不同时间返回受感染心脏的速度有多快？病毒清除后，心脏中的表位在多长时间内仍可检测到？病毒特异性CD4+和CD8+ T细胞如何促进病毒清除和免疫病理性心脏病的发展？

DESCRIPTION (provided by applicant): Coxsackieviruses are the commonest infectious cause of acute myocarditis, a disease that causes substantial human morbidity and mortality. Even after the virus has (apparently) been cleared, low- grade inflammation may continue, eventually leading to the serious outcome of dilated cardiomyopathy. There is general agreement that the innate and adaptive host immune responses contribute both to virus control, and to (immunopathological) heart disease. However, our knowledge of coxsackievirus-induced immune responses is rudimentary. In this proposal, using existing and new mouse models of coxsackievirus B3 (CVB3) infection, we shall evaluate the intracardiac effects of type I interferons (T1IFN) on acute and persistent CVB3 infection, and we shall use a unique set of reagents, developed in my laboratory, to assess CVB-specific T cell responses in the hearts of infected mice. There are 3 Specific Aims : 1. The effects of T1IFN in the heart are controversial. Some published work suggests that these innate cytokines may clear virus from the heart, but other work has suggested that they play no role whatsoever within the infected heart. We shall cross two existing mouse strains to develop a new mouse model in which the expression of T1IFN receptor on cardiomyocytes can be ablated at will. These mice will allow us to resolve the above controversy, and to determine if T1IFN is responsible for constraining viral spread in the acutely-infected heart. In addition, by removing this receptor during persistent infection, we shall be able to determine if T1IFN is required for the maintenance of the persistent state. 2. Despite many years of study, our understanding of CVB-specific T cell responses remains minimal. To address this deficiency, my lab has generated a variety of unique reagents including recombinant CVB that expressed well-characterized CD4+ and CD8+ T cell epitopes, and genetically-marked T cells specific for those epitopes. We shall exploit our reagents to investigate the kinetics of CVB- specific CD4+ & CD8+ T cell infiltration in the heart over the course of acute myocarditis, and will determine the extent to which this T cell infiltration is regulated by T1IFN. 3. We also shall use the above reagents to map CVB3 antigen expression within the heart during acute and persistent infection. In which heart cells are antigens expressed? How quickly do antigen- specific CD4+ and CD8+ T cells home to the infected heart at various times after infection? For how long after viral clearance do epitopes remain detectable in the heart? How do virus-specific CD4+ and CD8+ T cells contribute to virus clearance, and to the development of immunopathological heart disease?