Role of CD8+ T Cells in TMEV Resistance and Susceptibili

说明（申请人提供） 脑内接种Theiler小鼠脑脊髓炎病毒（TMEV）导致慢性 炎性脱髓鞘导致易感小鼠的临床症状。鉴于潜在的病毒病因学和慢性脱髓鞘进展的相似性，该TMEV系统被认为是研究人类多发性硬化症（MS）的最佳动物模型之一。已经报道了对TMEV特异性的II类限制性CD 4 + T细胞应答的广泛研究，其似乎在病毒发病机制中起重要作用。使用X32-微球蛋白和穿孔素缺陷小鼠缺乏细胞毒性T细胞功能，我们已经证明，细胞毒性功能是重要的保护，从这种病毒诱导的脱髓鞘疾病的耐药小鼠与C57 BL/6的背景。然而，人们对针对TMEV的I类限制性CD 8 + T细胞反应知之甚少，特别是在易感毒株中，尽管已知这种类型的反应在保护宿主免受病毒感染方面最有效。在过去的资助期间，我们已经确定了一个主要的和两个次要的H-2Db限制性CTL表位的耐药C57 BL/6小鼠，以及类似的一个主要的和两个亚显性H-2KS限制性CTL表位的敏感SJL/J小鼠，使用 TMEV的整个衣壳蛋白的重叠肽。由于对TMEV诱导的脱髓鞘的抗性与H2 D位点相关，并且易感小鼠缺乏病毒特异性H-2D限制性细胞毒性T细胞，我们推测病毒特异性CD 8+细胞毒性T细胞的效率和/或频率可能取决于抗性小鼠和易感小鼠之间I类限制的差异。我们建议在这里检查的作用和命运的细胞毒性T细胞的特异性的优势和亚优势的病毒表位的阻力和/或易感性泰勒病毒引起的脱髓鞘疾病作为人类多发性硬化症的模型。拟开展的研究的具体目的包括：1）评估脱髓鞘疾病过程中耐药和易感小鼠中病毒表位特异性CD 8 + T细胞的水平和命运; 2）确定病毒特异性CD 8 + T细胞在TMEV诱导的脱髓鞘疾病的预防和/或发病机制中的作用;（3）探讨TMEV特异性CTL H-2D和H-2K限制在TMEV耐药/易感性中的意义以及这种偏斜限制的可能机制。我们相信，我们提出的研究将产生关于抗病毒诱导的潜在控制机制的重要信息， 免疫介导的脱髓鞘，这是研究人类MS的相关动物模型。

Description (provided by applicant) ntracerebral inoculation of Theiler's murine encephalomyelitis virus (TMEV) results in chronic inflammatory demyelination leading to clinical symptoms in susceptible mice. In light of the potential viral etiology and similarities in the progression of chronic demyelination, this TMEV system is considered to be one of the best animal models for studying human multiple sclerosis (MS). Extensive studies on the class II-restricted, CD4+ T cell response specific for TMEV, which appears to play an important role in viral pathogenesis, have been reported. Using X32-microglobulin and perforin deficient mice lacking cytotoxic T cell function, we have demonstrated that cytotoxic function is important for protection from this virus-induced demyelinating disease in resistant mice with the C57BL/6 background. However, very little is known about the class I-restricted, CD8+ T cell response against TMEV particularly in susceptible strains, although this type of response is known to be the most efficient in protecting the host from viral infections. During the past grant period, we have identified one major and two minor H-2Db-restricted CTL epitopes for resistant C57BL/6 mice, and similarly one predominant and two subdominant H-2Ks-restricted CTL epitopes for susceptible SJL/J mice using overlapping peptides of the entire capsid proteins of TMEV. Because resistance to TMEV-induced demyelination is associated with the H2D locus and susceptible mice lack virus-specific, H-2Drestricted cytotoxic T cells, we speculate that the efficiency and/or frequency of virus-specific CD8+ cytotoxic T cells may be dependent on the differences in the class I restriction between resistant and susceptible mice. We propose here to examine the role and fate of these cytotoxic T cells specific for the predominant and subdominant viral epitopes in resistance and/or susceptibility to Theiler's virusinduced demyelinating disease as a model for human multiple sclerosis. The specific aims for the proposed studies include: 1) To assess the level and fate of CD8+ T cells specific for viral epitopes in resistant and susceptible mice during the course of demyelinating disease; 2) To determine the role of virus-specific CD8+ T cells in protection from and/or pathogenesis of TMEV-induced demyelinating disease; 3) To examine the significance of H-2D vs H-2K-restriction for TMEV-specific CTL in resistance/susceptibility and the potential mechanism of this skewed restriction. We believe that our proposed studies will yield important information on the potential control mechanism(s) against virusinduced, immune-mediated demyelination, which is a relevant animal model for studying human MS.