Immune tolerance in humanized translational models to cure diabetes

描述(申请人提供)：这项申请的重点是研究人类T细胞在1型糖尿病(T1D)的诱因和免疫耐受性的崩溃。我们寻求开发和利用一种新的人源化小鼠模型系统来直接评估诱导T细胞耐受和治疗糖尿病的临床相关治疗方法。我们已经开发了一种与人类相关的小鼠模型，我们可以在体内实时想象，以解决糖尿病期间免疫细胞和靶胰腺β细胞之间相互作用的基本机制。该模型系统将有助于促进治疗药物的测试，以选择性地针对糖尿病人T细胞治疗T1D，作为临床前模型和试验台和床边之间的桥梁。这项应用的总体目标是利用人源化的小鼠模型来识别导致糖尿病的主要免疫靶点，并选择性地使这些破坏性T细胞沉默。我们的中心假设是胰岛抗原，包括胰岛素、胰岛素原、GAD、IA2和IGRP是免疫系统的主要靶标，并导致β细胞死亡和糖尿病。我们的假设是建立在强有力的研究基础上的，该研究表明，化学固定在耐受细胞上的胰岛素蛋白能够逆转新发糖尿病NOD小鼠的糖尿病。尽管在小鼠模型中，这些蛋白作为糖尿病发病机制的靶点，但我们并不完全了解人类T1D患者的特异性T细胞反应。我们已经启动了一项强有力的合作，使用人源化的小鼠模型来询问糖尿病发展过程中的人类免疫细胞，以研究这些免疫靶点。利用一只表达糖尿病相关基因HLAA2.1和HLADQ8的转基因小鼠，在NOD.cerd.IL-2-RGamma c-/-小鼠MHC I-/-MHC II-/-背景上，我们将测试耐受疗法，选择性地将这些糖尿病相关蛋白作为翻译T1D的靶点。本应用的目标是1)建立和验证能够从人类白细胞抗原相合的糖尿病患者中进行多系免疫重建和糖尿病发生的人人类白细胞抗原人源化小鼠模型，2)利用活体双光子成像技术确定在人源化小鼠耐受和诱导糖尿病过程中人T细胞与胰岛移植组织的动态运动和细胞相互作用，以及3)表征和确定在人源化模型中诱导抗原特异性耐受后对移植胰岛的功能和生物免疫应答，以实现胰岛移植物的长期存活。 公共卫生相关性：这项研究将开发和验证一种新的人源化小鼠模型系统，以直接评估诱导T细胞耐受和治疗自身免疫性糖尿病的临床相关治疗方法。在这项应用中，我们将在人源化的小鼠中研究来自糖尿病和健康患者的人类免疫细胞，以确定作为耐受治疗的胰岛β细胞上的免疫靶点。这个模型具有显著的翻译相关性，因为这种治疗方法可以直接应用于糖尿病患者，因为耐受的基本机制将使用人类糖尿病患者的免疫细胞和人类胰岛进行检查。

DESCRIPTION (provided by applicant): This application is focused on studying human T cells during the induction of type 1diabetes (T1D) and the breakdown of immunological tolerance. We seek to develop and utilize a novel humanized mouse model system to directly assess clinically relevant therapies to induce T cell tolerance and cure diabetes. We have developed a human relevant mouse model that we can imagine in vivo, in real time to address the basic mechanisms underlying the interplay between the immune cells and the target pancreatic beta cells during diabetes. This model system will help facilitate the testing of therapeutics to selectively target diabetogenic human T cells for treatment of T1D, as a pre-clinical model and a bridge between bench and bedside. The overall objective of this application is to utilize humanized mouse models to identify the major immune targets responsible for diabetes and selectively silence only these destructive T cells. Our central hypothesis is that islet antigens, including insulin, preproinsulin, GAD, IA2, and IGRP are major targets of the immune system and lead to beta cell death and diabetes. Our hypothesis has been formulated on the basis of strong research demonstrating that insulin protein chemically fixed to tolerogenic cells was able to reverse diabetes in newly diabetic NOD mice. Despite the role of these proteins as targets for diabetes pathogenesis in mouse models, we do not fully understand the specific T cell responses in human patients suffering from T1D. We have initiated a strong collaboration to investigate these immune targets using humanized mouse models to interrogate human immune cells during diabetes development. Using a transgenic mouse expressing the diabetes linked HLA I and HLA II alleles for HLA-A2.1 and HLA-DQ8 on the NOD.scid.IL-2-Rgamma c-/- mouse MHC I-/- MHC II-/- background we will test tolerogenic therapies to selectively target these diabetes relevant proteins as a translational T1D cure. The goals of this application are to 1) Establish and validate a human HLA humanized mouse model capable of multi-lineage immune reconstitution and diabetes development from HLA matched diabetic patients, 2) Determine the dynamic motility and cellular interactions of human T cells with islet graft tissue during the breakdown of tolerance and induction of diabetes in the humanized mouse using intravital two-photon imaging, and 3) Characterize and determine the functional and biological immune response against transplanted islets following antigen specific tolerance induction in the humanized model for long term islet graft survival. PUBLIC HEALTH RELEVANCE: This research proposed will develop and validate a novel humanized mouse model system to directly assess clinically relevant therapies to induce T cell tolerance and cure autoimmune diabetes. In this application we will investigate human immune cells from diabetic and healthy patients in a humanized mouse to determine the immune targets on islet beta cells as tolerogenic therapies. This model has significant translational relevance because this therapeutic approach can be directly applied to diabetic patients since the basic mechanism for tolerance will be examined using human diabetic patient immune cells and human islets.