Defining mechanisms of CD8 T cell exhaustion in T1D

项目摘要/摘要 治疗1型糖尿病(T1D)的关键障碍，T1D是一种自身免疫性疾病，胰岛β细胞 被免疫细胞摧毁，就是了解疾病的异质性。免疫的一个来源 最近在新近发病的T1D受试者中发现的异质性是存在部分耗尽的CD8 对抗CD3治疗有效的受试者的T细胞(Long等科学免疫学)。同样， 疾病进展较慢的受试者胰岛特异性CD8 T细胞的频率较高， 精疲力竭的特征。然而，T1D耗竭的潜在机制还不是很清楚。通过 相比之下，在慢性病毒环境中，IL-2/IL-15轴参与分化和 持久性和CD8耗竭：IL-2的增加阻止分化，而对IL-2/IL-2的反应- 15是持久性所必需的。在T1D上，我们与其他人一起发表了开创性的研究，这些研究将 IL-2/IL-15轴与T1D相关。在这里，我们发现T1D受试者耗尽CD8 T细胞的频率较低 在CD8耗竭细胞中有较高水平的CD4 IL-2产生和较低水平的IL-15反应。因此，IL- 与T1D相关的2/IL-15缺陷为阐明IL-2在CD8中的作用提供了一个独特的机会 疲惫不堪。我们假设T1D中IL-2/IL-15轴的变化导致 分化为胰岛特异性耗尽的CD8 T细胞，持续性降低。我们将对此进行测试 两个聚焦目标的假设使用来自已建立的T1D，Pre-Td的精心挑选的人类队列的样本 临床T1D和健康对照(HC)受试者，以及包括质量块在内的多维单细胞方法 细胞学(CyTOF)、RNA-seq和atac-seq与创新的系统免疫学方法相结合。在……里面 目的1，我们建议阐明增加的CD4IL2的产生导致减少力竭的机制 处于疾病的不同阶段。在目标2中，我们将阐明IL-12/IL-15反应降低的机制。 疲惫的CD8 T细胞，导致疲惫的有限持久性。圆满完成这些目标 1)是否会促进我们对CD8 T细胞耗竭的理解，因为CD8 T细胞耗竭是T1D中一种未被研究的耐受形式，2) 提高我们对导致T1D疾病进展的免疫因素的了解，以及3)提供 为开发旨在促进疲惫的疗法而设立的基金会。

PROJECT SUMMARY/ABSTRACT A critical barrier to treating Type 1 Diabetes (T1D), an autoimmune disease in which the islet beta cells are destroyed by immune cells, is understanding the heterogeneity of disease. One source of immune heterogeneity recently identified across recent onset T1D subjects is the presence of partially exhausted CD8 T cells in subjects with beneficial response to anti-CD3 therapy (Long, et.al Science Immunology). Likewise, subjects with slower disease progression have great frequencies of islet-specific CD8 T cells with more features of exhaustion. Yet, the mechanisms underlying exhaustion in T1D are not well understood. By contrast, in chronic viral settings it is well established that the IL-2/IL-15 axis is involved in differentiation and persistence and CD8 exhaustion: increased IL-2 availability prevents differentiation, while response to IL-2/IL- 15 is required for persistence. In T1D, we published seminal studies along with others that link alterations in the IL-2/IL-15 axis with T1D. Here, we find that T1D subjects with lower frequencies of exhausted CD8 T cells have higher levels of CD4 IL-2 production and lower levels of IL-15 response in CD8 exhausted cells. Thus, IL- 2/IL-15 defects associated with T1D present a unique opportunity to elucidate the role of IL-2 on CD8 exhaustion. We hypothesize that alterations in the IL-2/IL-15 axis in T1D lead to decreased differentiation into islet-specific exhausted CD8 T cells and reduced persistence. We will test this hypothesis in two focused aims using samples from well curated human cohorts of established T1D, pre- clinical T1D and healthy control (HC) subjects, and multi-dimensional single cell approaches including mass cytometry (CyTOF), RNA-seq and ATAC-seq combined with innovative systems immunology approaches. In Aim 1, we propose to elucidate mechanisms of increased CD4 IL2 production that lead to reduced exhaustion at different stages of disease. In Aim 2, we will elucidate mechanisms of reduced IL-12/IL-15 response in exhausted CD8 T cells that results in limited persistence of exhaustion. Successful completion of these aims will 1) advance our understanding of CD8 T cell exhaustion as an understudied form of tolerance in T1D, 2) improve our understanding of immune factors contributing to T1D disease progression, and 3) provide the foundation for the development of therapies designed to promote exhaustion.