Role of T Cell Epitopes in Coronavirus Pathogenesis

描述（由申请方提供）：小鼠肝炎病毒（MHV）感染 小鼠中枢神经系统为慢性脱髓鞘的研究提供了动物模型 多发性硬化症（MS）。MHV-A59和MHV-4（JHM）毒株 在C57 Bl/6中引起急性脑炎，随后是慢性脱髓鞘疾病 小鼠我们的长期目标是了解MHV的发病机制。在 在这个建议中，我们将重点关注病毒特异性CD 8 + T细胞的作用 CNS发病机制的反应。很明显，CD 8 + T细胞应答在免疫应答中起着重要作用。 在急性感染期间，在病毒从CNS清除中起关键作用。 对MHV的各种分离株和突变株的研究表明， 脑炎是后期脱髓鞘发展所必需的， 在没有可检测到的感染性病毒的情况下发生，但存在 病毒RNA我们的假设是，CD 8 +T细胞应答在 在病毒复制/传播与清除之间实现平衡， 宿主免疫反应，这种平衡（决定免疫水平） 脑炎）是必要的，以建立条件，导致病毒RNA 持久性和脱髓鞘。我们将研究如何改变CD 8 + 反应影响急性感染并进展为慢性脱髓鞘。我们 将使用仅在刺突基因上不同的同基因病毒， MHV-4尖峰或A59背景内的A59尖峰。虽然这两种病毒 诱导脱髓鞘，它们在诱导脑炎的程度和 CD 8 + T细胞表位;因此，我们认为，每一个已经进化出一个平衡的病毒， 复制/传播与以不同方式清除，两者都会导致 脱髓鞘 而MHV-4刺突含有免疫显性S510-518（H-2Db）表位， 与亚显性S598-605（H-2Kb）相比，A59刺突仅表达 S598-605。我们选择了S510-518发生改变的重组病毒， 将选择两个表位都有失活突变的病毒。我们将使用 这些病毒来测试我们的预测， 将改变急性和慢性疾病的发病机制。最后，使用 互补的方法，我们将开发一种模型，其中CD 8缺陷小鼠 将被表达外源CD 8 +T细胞的重组MHV感染 表位我们将确定转移不同数量的 表位特异性CD 8 + T细胞的清除和发病机制。

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.