Regulatory cells involved in the suppression of active EAE

为了研究外周中髓鞘抗原特异性自身反应性T细胞的抑制机制，我们产生了表达从MS患者分离的髓鞘碱性蛋白（MBP）特异性人T细胞受体（TCR）的转基因（Tg）小鼠。由于常规的髓鞘抗原特异性TCR Tg小鼠是由致脑炎性T细胞克隆产生的，因此由致脑炎性TCR产生的Tg小鼠发生自发性或主动性EAE。然而，不可能从人类中鉴定致脑炎性T细胞克隆。我们选择了在表达HLA-DRB 1 *0401的人中识别MBP的免疫显性表位MBP 111 -129的T细胞克隆。有趣的是，CD 4 + CD 25- Tg T细胞可以在体外分化为Th 1细胞，并且Th 1细胞在过继转移后诱导EAE，而用MBP 111 -129/CFA免疫不能在MS 2 - 3C 8 TCR Tg小鼠中诱导EAE。该初步实验表明，在MS 2 - 3C 8 TCR Tg小鼠中产生了能够抑制致脑炎性T细胞分化的TCR 4。我们发现，MHC II类限制性MBP特异性CD 8 + Tg T细胞与CD 4 + Tg T细胞一起在MS 2 - 3C 8 Tg小鼠中发育。CD 8 + Tg T细胞具有细胞毒性，并产生大量的IFN-？对MBP 111 -129/HLA-DRB 1 *0401复合物应答，并表现出Tc 1表型。我们还发现，8-12%的CD 4 + Tg na？在MS 2 - 3C 8 Tg小鼠中，ve T细胞表达CD 4 + CD 25 + Foxp 3+表型，并且这些Tg T细胞抑制CD 4 + CD 25-Tg T细胞的增殖。这些CD 8 + Tg T细胞和CD 4 + CD 25 + Tg T细胞是抑制活性EAE诱导的候选T细胞。在这项研究中，我们将确定调节性T细胞亚群，可以抑制活动性EAE，并探讨其对其他髓鞘抗原，PLP和MOG诱导的EAE的抑制潜力。这项研究可能会导致更好地了解TcR及其抑制机制，并为NIH RO 1的应用奠定坚实的基础。1名主要研究者/项目负责人（最后，第一，中间）：Ito，Kouichi

To study the suppressive mechanism of myelin antigen-specific autoreactive T cells in the periphery, we have generated transgenic (Tg) mice expressing Myelin Basic Protein (MBP)-specific human T cell receptor (TCR) isolated from an MS patient. Since conventional myelin antigen-specific TCR Tg mice were generated from encephalitogenic T cell clones, the Tg mice generated from the encephalitogenic TCR developed spontaneous or active EAE. However, it is impossible to identify encephalitogenic T cell clones from humans. We chose the T cell clone which recognize the immunodominant epitope of MBP, MBP111-129, in humans expressing the HLA-DRB1*0401. Interestingly, CD4+CD25- Tg Tcells can differentiate into Th1 cells in vitro and the Th1 cells induce EAE upon adoptive transfer, while EAE cannot be induced in the MS2-3C8 TCR Tg mice by immunization with MBP111-129/CFA. This preliminary experiment suggests that Tregs capable of suppressing the differentiation of encephalitogenic T cells develop in the MS2-3C8 TCR Tg mice. We found that MHC class II-restricted MBP-specific CD8+ Tg T cells develop together with CD4+ Tg T cells in the MS2-3C8 Tg mice. The CD8+ Tg T cells are cytotoxic and produce a high amount of IFN-? in response to MBP111-129/HLA-DRB1*0401 complexes and exhibit Tc1 phenotype. We also found that 8-12% of CD4+ Tg na?ve T cells express CD4+CD25+ Foxp3+ phenotype in the MS2-3C8 Tg mice and these Tg Tregs suppress the proliferation of CD4+ CD25-Tg T cells. These CD8+ Tg T cells and CD4+CD25+ Tg T cells are candidate Tregs which suppress the induction of active EAE. In this study, we will identify the regulatory T cell subsets which can suppress active EAE and investigate their suppressive potential against EAE induced by other myelin antigens, PLP and MOG. This study could lead to a better understanding of Tregs and their suppressive mechanism and a solid ground for a NIH RO1 application. 1 Principal Investigator/Program Director (Last, First, Middle): Ito, Kouichi