Peripheral Tolerance Induction by Lymph Node Stromal Cells and Dendritic Cells

外周耐受性，或潜在的自身反应性T细胞的消除或功能性沉默，取决于 将自身抗原呈递给T细胞。为了了解自身抗原呈递如何导致耐受性或 自身免疫是我们工作的长期目标。这一建议是基于这样一个假设，即淋巴结 基质细胞(LNSCs)是高度特化的抗原提呈细胞，可将自身耐受性强加于 循环中的T细胞。有几个发现导致了这一假设。首先，类似于髓质胸腺上皮细胞 (MTECs)，LNSCs结构性地表达外周组织抗原(PTA)，以及自身免疫调节因子 (AIRE)基因，部分控制PTA表达和中枢耐受诱导的转录调节因子 由mTEC提供。其次，LNSCs定位于淋巴结的皮质，这是一个理想的位置 与循环中的T细胞相互作用。第三，LNSCs可以将内源性表达的抗原加工成多肽- MHC复合体，并诱导幼稚的、抗原特异的T细胞增殖。第四，介绍 LNSCs内源性表达PTA足以促进抗原特异性缺失耐受 T细胞。这项建议的目的是剖析LNSCs的分子和细胞机制。 CDS和CD4T细胞递呈自身抗原及其在对Key的耐受性中的作用 自身抗原。 具体目的是：1)研究小鼠和人LNSCs的一般功能特性。这里 我们将表征LNSCs的转录图谱以及Aire在这些新的APC中的作用。我们会 然后评估小鼠LNSCs的PTA表达是否与实验中的疾病易感性有关 自身免疫性脑脊髓炎(EAE)和1型糖尿病(T1D)；2)确定LNSCs在促进 MHC I类和11类限制性自身反应性T细胞之间的耐受性。我们将确定LNSCs是否 促进对胰岛特异性葡萄糖-6-磷酸酶的耐受性，胰岛特异性葡萄糖-6-磷酸酶是一种胰腺抗原，在T1D中使用 8.3 TCR转基因小鼠模型，其中致病CD8+T细胞破坏产生胰岛素的β细胞。 这些研究的结论将使用5b6 TCR转基因小鼠模型进行一般性检验 在EAE中，CD4+T细胞识别髓鞘蛋白、蛋白脂蛋白；3)确定 炎症对LNSCs的功能有影响。我们将检查炎症对功能的影响 和LNSCs的基因表达谱。这些研究的结果将阐明LNSC是否 耐受性或自身抗原提呈能力是否在 炎症状态。

Peripheral tolerance, or the elimination or functional silencing of potentially auto-reactive T cells, relies on the presentation of self-antigen to T cells. To understand how self-antigen presentation leads to tolerance or autoimmunity is the long-term goal of our work. This proposal is based on the hypothesis that lymph node stromal cells (LNSCs) are highly specialized antigen presenting cells that impose self-tolerance on circulating T cells. Several findings lead to this hypothesis. First, like medullary thymic epithelial cells (mTECs), LNSCs constitutively express peripheral tissue antigens (PTAs), and the autoimmune regulator (Aire) gene, a transcriptional regulator that partially controls PTA expression and central tolerance induction by mTECs. Second, LNSCs are localized in the cortex of the lymph node, which is an ideal location for interacting with circulating T cells. Third, LNSCs can process endogenously expressed antigen into peptide- MHC complexes and induce proliferation in naive, antigen-specific T cells. Fourth, the presentation of endogenously expressed PTA by LNSCs is sufficient to promote deletional tolerance among antigen-specific T cells. The objective of this proposal is to dissect the molecular and cellular mechanisms by which LNSCs present self-antigens to CDS and CD4 T cells and to evaluate their role in imposing tolerance to key autoantigens. The specific aims are to: 1) Investigate the general functional properties of mouse and human LNSCs. Here we will characterize the transcriptional profile of LNSCs and the role of Aire in these novel APCs. We will then assess whether PTA expression by mouse LNSCs is linked to disease susceptibility in experimental autoimmune encephalomyelitis (EAE) and type-1 diabetes (T1D); 2) Define the role of LNSCs in promoting tolerance among MHC class I- and class ll-restricted self-reactive T cells. We will determine whether LNSCs promote tolerance to islet-specific glucose-6-phosphatase, a pancreatic antigen that is targeted in T1D using the 8.3 TCR transgenic mouse model in which pathogenic CD8+ T cells destroy insulin-producing beta cells. Conclusions from these studies will be tested for generality using the 5B6 TCR transgenic mouse model of EAE in which CD4+ T cells recognize the myelin protein, proteolipid protein; 3) Ascertain whether the function of LNSCs is influenced by inflammation. We will examine the impact of inflammation on the function and gene expression profile of LNSCs. Results from these studies will elucidate whether LNSCs are constitutively tolerogenic or whether their capacity for self-antigen presentation is modified under inflammatory conditions.