基于TCR测序分析EAE发病过程中CD8 T细胞的功能和作用机制

多发性硬化是一类由致病性CD4 T细胞介导的自身免疫疾病。而临床观察发现病灶中存在大量CD8 T细胞浸润，但其作用仍存在较大争议。目前有研究认为CD8 T细胞在MS中发挥致病作用，另一些研究则认为其发挥免疫调节作用。我们认为CD8 T细胞TCR的多样性是导致这种争议的根本原因。前期研究我们对EAE中浸润的CD8 T细胞进行单细胞TCR-seq和RNA-seq分析，发现了一些在EAE病灶中特异性扩增的CD8 TCR克隆。这些克隆主要富集在2群细胞中，其中一群特异性高表达共抑制性分子及相关转录因子，另一群则高表达颗粒酶素相关基因，提示这2群细胞在EAE中可能起着不同作用。本项目拟通过克隆这些富集的CD8 TCR去探究它们在EAE中的作用。结合我们已筛选获得的自身抗原肽库，进一步探究激活这些CD8 T细胞的抗原肽，阐明MS/EAE中CD8 T细胞的功能和作用机制，为MS的临床治疗提供理论依据。

Multiple sclerosis is a kind of autoimmune disease mediated by pathogenic CD4 T cells. While clinical observation revealed that large numbers of CD8 T cells were infiltated in the lessions. Howerver, its role is still controversial. Some research suggested that CD8 T cells played pathogenic roles in MS, while ohters suggested that it played immuregulatory roles. We believe that the TCR diversity of CD8 T cells is the root cause of this controversy. In our previous research, CD8 T cells infiltrated in the CNS of EAE mouse model were isolated for single-cell RNA-seq and TCR-seq. We found some highly expanded CD8 T cell clones. These clones maily enriched in 2 clusters. Some inhibitory molecules and related transcription factors were highly expressed in one of these clusters specificly, while granzymes were highly expessed in the other one specificly. TCR-seq showed that highly clonal expansion CD8 TCRs were enriched in cluster1 and cluster2. It suggested that the two clusters may play different functions in EAE diseas. In this project we aim to explore the functions of CD8 T cells in EAE by cloning the enriched CD8 TCR, then further explore the peptide which activates these CD8 T cells in combination with the auto-antigen peptide repertoire we have screened. And we aim to clarify the function and mechanism of different CD8 T cells in MS/EAE, thus providing theoretical foundation for the clinic treatment of MS.