Role of T Cell Epitopes in Coronavirus Pathogenesis

描述(申请人提供)：感染鼠肝炎病毒(MHV) 小鼠中枢神经系统为慢性脱髓鞘研究提供了动物模型 多发性硬化症(MS)等疾病。MHV-A59和MHV-4(JHM)毒株 C57BL/6引起急性脑炎继发慢性脱髓鞘病 老鼠。我们的长期目标是了解MHV的致病机制。在……里面 本提案中，我们将重点介绍病毒特异性CD8 T细胞的作用 在中枢神经系统发病机制中的反应。很明显，CD8 T细胞反应在 在急性感染期间，病毒从中枢神经系统中清除的关键作用。 对MHV不同分离株和突变体的研究表明，在一定程度上 脑炎是脱髓鞘后期发展所必需的，它 在没有检测到传染性病毒的情况下发生，但在 病毒核糖核酸。我们的假设是CD8 T细胞反应在 在病毒复制/传播与病毒清除之间取得平衡 宿主免疫反应和这种平衡(它决定了 脑炎)是建立导致病毒RNA的条件所必需的 顽固性和脱髓鞘。我们将调查CD8的变化如何 反应影响急性感染和进展为慢性脱髓鞘。我们 将使用仅在Spike基因上不同的同源病毒，表达 A59背景中的MHV-4尖峰或A59尖峰。虽然这两种病毒 诱导脱髓鞘，它们在诱发脑炎的程度和在 CD8T细胞表位；因此，我们认为每个表位都进化出了病毒的平衡 复制/传播与清除的方式不同，两者都会导致 脱髓鞘。 而MHV-4尖峰包含免疫优势的S510-518(H-2DB)表位，如 和亚显性的S598-605(H-2kb)一样，A59穗只表达 S598-605。我们选择了S510-518和S510-518中有变化的重组病毒 将选择在两个表位上都有失活突变的病毒。我们将使用 这些病毒来测试我们预测的两个表位之一的变化 会改变急慢性疾病的发病机制。最后，使用 补充方法，我们将建立一种CD8缺陷小鼠的模型 将感染表达外源CD8 T细胞的重组MHV 表位。我们将确定将不同数量的 特异性CD8T细胞表位的清除及其致病机制。

DESCRIPTION (provided by applicant): Mouse hepatitis virus (MHV) infection of the mouse CNS provides an animal model for the study of chronic demyelinating disease such as multiple sclerosis (MS). The MHV-A59 and MHV-4 (JHM) strains cause acute encephalitis followed by chronic demyelinating disease in C57Bl/6 mice. Our long-term goal is to understand the mechanism of MHV pathogenesis. In this proposal, we will focus on the role of the virus-specific CD8+ T cell response in CNS pathogenesis. It is clear that the CD8+ T cell response plays a crucial role in viral clearance from the CNS during the acute infection. Studies of various isolates and mutants of MHV suggest that some level of encephalitis is necessary for the later development of demyelination, which occurs in the absence of detectable infectious virus but in the presence of viral RNA. Our hypothesis is that the CD8+T cell response is important in achieving a balance between virus replication/spread versus clearance by the host immune response and that this balance (which determines the level of encephalitis) is necessary to set up the conditions that lead to viral RNA persistence and demyelination. We will investigate how alteration of the CD8+ response effects acute infection and progression into chronic demyelination. We will use isogenic viruses that differ only in the spike gene, expressing either the MHV-4 spike or the A59 spike within the A59 background. While both viruses induce demyelination, they differ in the extent of encephalitis induced and in CD8+ T cell epitopes; thus we suggest that each has evolved a balance of viral replication/spread versus clearance in a different way, both resulting in demyelination. While the MHV-4 spike contains the immunodominant S510-518 (H-2Db) epitope as well as the subdominant S598-605 (H-2Kb), the A59 spike expresses only S598-605. We have selected recombinant viruses with alterations in S510-518 and will select viruses with inactivating mutations in both epitopes. We will use these viruses to test our prediction that alteration of one of both epitopes will alter the pathogenesis of acute and chronic disease. Finally, using a complementary approach, we will develop a model in which CD8 deficient mice will be infected with a recombinant MHV expressing a foreign CD8+T cell epitope. We will determine the effects of transferring various numbers of epitopes specific CD8+ T cells on clearance and pathogenesis.