T Cell Tolerance by DEC-205-mediated Islet Antigen Delivery to Dendritic Cells

1型糖尿病(T1D)是一种自身免疫性疾病，其特征是T细胞介导的 胰岛细胞。NOD小鼠构成了广泛研究的T1D共享多个 具有人类疾病的特征。我们对T细胞靶向的至少部分抗原的了解 NOD小鼠和T1D患者的细胞现在都可以实际用于开发基于抗原的策略来 干扰致病的自身反应性T细胞群并更好地理解和增强自然 耐受诱导途径。树突状细胞(DC)对启动获得性免疫反应至关重要 对病原体来说。然而，在稳定状态下，DC以耐受性方式向T细胞递送抗原，并 对于建立外周耐受性很重要。虽然已知这是在小鼠身上出现的情况，但 不倾向于自身免疫的发展，我们最近在一个 自发性自身免疫性疾病。我们递送了一种模拟表位多肽，可被糖尿病原性结节识别 CD8+T细胞克隆AI4在NOD小鼠DC中的应用 受体DEC-205。最初观察到转移的抗原特异性T细胞的增殖，但这是 然后删除。因此，树突状细胞的选择性抗原靶向导致转移的自身反应的缺失 在已知耐受性缺陷的NOD小鼠中，CD8+T细胞即使在正在进行的自身免疫的背景下也是如此。而当 很有希望，在应用这种方法之前，必须进行大量的额外调查 技术对T1D患者的影响。我们的目标是以循序渐进的方式将这一战略转变为人性化 小鼠模型与T1D患者的相关性日益增强。提出了四个具体目标： 目标1a。确定细胞抗原的CD8+T细胞表位靶向是否稳定 经DEC-205途径的DC可导致HLA-A*0201-的内源性抗原特异性T细胞缺失 转基因NOD小鼠。 目标1b。树突状细胞抗原靶向预防HLAA中T1D的效果 0201-转基因NOD小鼠。 目标2a。DEC-205靶向DC的胰岛素原前体及监测内源性胰岛素原对DC的影响 人类白细胞抗原A*0201转基因NOD小鼠体内CD8+和CD4+胰岛素特异性T细胞的研究 目标2b。树突状细胞靶向胰岛素原预防HLAA中T1D的效果 0201-转基因NOD小鼠。 目的3.确定人胰岛反应性T细胞能否耐受DEC- 205-介导的细胞抗原递送到DC。 目的4.确定反应中观察到的T细胞耐受机制 涉及DEC-205介导的向树突状细胞递送细胞抗原。

Type 1 diabetes (T1D) is an autoimmune disease characterized by T cell-mediated destruction of the pancreatic islet β cells. NOD mice constitute an extensively studied model for T1D sharing many characteristics with the human disease. Our knowledge of at least some of the β cell antigens targeted by T cells in both NOD mice and T1D patients can now be used practically to develop antigen-based strategies to interfere with pathogenic autoreactive T cell populations and to better understand and augment natural tolerance induction pathways. Dendritic cells (DCs) are critical for the initiation of adaptive immune responses to pathogens. However, in the steady-state, DCs present antigens to T cells in a tolerogenic manner and are important for the establishment of peripheral tolerance. While this was known to be the case in mice that are not prone to the development of autoimmunity, we recently evaluated this concept in the setting of a spontaneous autoimmune disease. We delivered a mimotope peptide, recognized by the diabetogenic NODderived CD8+ T cell clone AI4, to DCs in NOD mice using a peptide-linked antibody to the DC endocytic receptor DEC-205. Proliferation of transferred antigen-specific T cells was initially observed, but this was followed by deletion. Thus, selective antigen targeting of DCs leads to deletion of transferred autoreactive CD8+ T cells even in the context of ongoing autoimmunity in NOD mice with known tolerance defects. While promising, a substantial quantity of additional investigation must be performed before the application of such technology to patients with T1D. Our objectives are to move this strategy in a stepwise fashion to humanized mouse models of increasing relevance to patients with T1D. Four Specific Aims are proposed: Aim 1a. To determine whether targeting of CD8+ T cell epitopes of β cell antigens to steadystate DCs via DEC-205 can result in deletion of endogenous antigen-specific T cells in HLA-A*0201- transgenic NOD mice. Aim 1b. To test the efficacy of antigen targeting to DCs for the prevention of T1D in HLAA* 0201-transgenic NOD mice. Aim 2a. To target preproinsulin to DCs via DEC-205 and monitor the response of endogenous CD8+ and CD4+ insulin-specific T cells in HLA-A*0201-transgenic NOD mice. Aim 2b. To test the efficacy of preproinsulin targeting to DCs for the prevention of T1D in HLAA* 0201-transgenic NOD mice. Aim 3. To determine whether human islet-reactive T cells can be tolerized in response to DEC- 205-mediated delivery of β cell antigens to DCs. Aim 4. To determine the mechanisms responsible for the T cell tolerance observed in response to DEC-205-mediated delivery of β cell antigens to dendritic cells.