T CELL RECEPTORS INVOLVED IN TMEV INDUCED DEMYELINATION

脑内接种Theiler小鼠脑脊髓炎病毒（TMEV）导致慢性炎性脱髓鞘，导致易感小鼠出现临床体征。 TMEV系统被认为是一种相关的感染性动物模型，可替代实验性自身免疫性脑脊髓炎（EAE）系统，用于研究人类多发性硬化症（MS）的潜在病毒病因学和慢性脱髓鞘进展的相似性。 以前，我们已经确定了主要的Th表位占超过85%的Th反应TMEV。 此外，我们已经确定了Th表位（VP 1233 -250和VP 274 -86，但不是VP 324 -37）参与脱髓鞘的发病机制和它们的关联，以诱导相对高水平的Th反应。 我们进一步观察到，Jbeta 1区域多态性与脱髓鞘的易感性相关，易感的H-2Ds MHC基因座可以覆盖TCR β链基因型的耐药效应。 此外，我们最近选择了自发产生的非致病性变异病毒，其在主要Th 1表位VP 1233 -250内的位置244处含有单个氨基酸取代，导致向Th 2应答的转换。 此外，由TMEV感染诱导的初始脱髓鞘导致对主要髓鞘组分的自身免疫Th应答的发展。 我们最近对CNS中浸润性T细胞的光谱分析和TCR CDR 3分析的初步研究表明，某些T细胞群体的克隆扩增早在病毒感染后7天就很明显。一些主要人群似乎在整个病程中持续存在。 与具有已知特异性的杂交瘤的CDR 3序列相比，这些T细胞代表病毒和/或自身抗原反应性群体。 基于这些初步的结果，我们建议相关的TCR库在中枢神经系统的发展TMEV诱导的脱髓鞘。在本申请中提出了三个具体目的：（1）CNS中TCR库与TMEV诱导的脱髓鞘的发病机制的相关性;（2）病毒特异性和自身反应性T细胞在脱髓鞘的发病机制中的作用;和（3）另外的V β或抗性MHC I类基因在CNS中TCR库的选择中的影响。我们相信，我们提出的研究将产生重要的信息的作用，浸润的T细胞群体和他们的扩张的发病机制中的病毒诱导的，T细胞介导的脱髓鞘，导致最终发展的自身免疫CNS自身抗原。

Intracerebral inoculation of Theiler's murine encephalomyelitis virus (TMEV) results in chronic inflammatory demyelination leading to clinical signs in susceptible mice. The TMEV system is considered to be a relevant infectious animal model, an alternative to the experimental autoimmune encephalomyelitis (EAE) system, for studying human multiple sclerosis (MS) in light of the potential viral etiology and similarities in the progression of chronic demyelination. Previously, we have identified major Th epitopes accounting for greater than 85 percent of the Th response to TMEV. In addition, we have identified the Th epitopes (VP1233-250 and VP274-86, but not VP324-37) involved in the pathogenesis of demyelination and their association to induce relatively high levels of Th responses. We have further observed that the Jbeta1 region polymorphism is associated with susceptibility to demyelination and that the susceptible H-2Ds MHC locus can override the resistant effect of the TCR beta-chain genotype. Furthermore, we have recently selected spontaneously arising non-pathogenic variant viruses containing a single amino acid substitution at position 244 within the major Th1 epitope, VP1233-250, resulting in a switch to Th2 response. Moreover, the initial demyelination induced by TMEV infection leads to the development of autoimmune Th response to a major myelin component. Our recent preliminary studies for spectratyping and TCR CDR3 analyses of infiltrating T cells in the CNS indicate that clonal expansion of certain T cell populations is apparent as early as 7 d after viral infection. Some of the major population appear to be persistent throughout the disease course. In comparison with CDR3 sequences of hybridomas with known specificity, these T cells represent virus- and/or autoantigen-reactive populations. Based on these preliminary results, we propose to correlate the TCR repertoire in the CNS with the development of TMEV-induced demyelination. Three specific aims are proposed in this application: (1) Correlation of the TCR repertoire in the CNS with the pathogenesis of TMEV-induced demyelination; (2) Role of virus- specific and autoreactive T cells in the pathogenesis of demyelination; and (3) Influence of additional Vbeta or resistant MHC class I genes in the selection of TCR repertoire in the CNS. We believe that our proposed studies will yield important information on the role of infiltrating T cell populations and their expansion in the pathogenesis of virus-induced, T cell-mediated demyelination, leading to the eventual development of autoimmunity to CNS autoantigens.