Engineering and targeting novel antigen-specific tolerogenic interfaces

 描述(申请人提供)：自身免疫性疾病是免疫耐受性受损的结果，动物研究表明，永久恢复抗原特异性耐受性可以构成治愈。然而，在人类身上实现这一点是非常具有挑战性的，因为他们在遗传和环境构成上具有高度异质性，而且疾病是多因素的。与此同时，这些疾病的发病率正在上升。这种异质性可以通过靶向诱导耐受的多种生物途径来克服，特别是在疾病驱动的自我反应性T细胞中，也可能在战略组织部位。药物、生物制品和/或耐受性抗原的各种组合已经在治疗中进行了测试，但在这种情况下，每个成分都独立起作用。缺少的是一个单一的“耐受性界面”，它使抗原性信号和多个耐受性信号一起并同时作用于靶T细胞，导致最佳的信号整合，并最终实现这些自我反应性T细胞的最佳重新编程。临床上最有益的结果是重新编程为抗原特异性调节性T细胞(Tregs)，这些T细胞寿命长，并能够通过抑制对其他疾病相关抗原(感染耐受)的自身免疫反应来维持耐受性。树突状细胞(DC)已经被测试用于治疗多种人类疾病，是可用于这一目的的最多功能的抗原提呈细胞之一。然而，由相关抗原和耐受信号的最佳组合组成的定制和复杂界面的创建尚未实现。有了这笔探索性/开发性拨款，我们建议设计新的基于DC的耐受界面，其成分通过电穿孔以mRNA混合物的形式输送。在特定目标1下，我们将测试几种抗原和耐受产物在该系统中的表达，并确定最有效地将糖尿病致T细胞重新编程为Treg的组合。主要目标是找到在诱导高功能和稳定的Tregs方面协同作用的信号通路，并在体内产生能够介导对疾病的长期保护的Tregs。在特定目标2下，我们将使用相同的基于mRNA的操作方法在DC中过度表达特定的归巢受体。其目的是促进耐受性DC向胰腺淋巴结或胰岛的迁移，在那里，糖尿病T细胞被启动，在那里它们发挥其致病功能。基于DC的细胞疗法在治疗人类疾病(主要是癌症)的临床试验中得到了越来越多的测试，最近还用于自身免疫。这些研究表明，DC没有迄今为止测试过的许多药物和生物制品的不良影响。产生耐受性的树突状细胞(1)靶向于特定的T细胞，(2)通过多种生物途径将其有效地重新编程为树突状细胞(Tregs)，(3)在相关组织中更好地和优先地积累，将极大地提高基于细胞的治疗自身免疫性疾病的有效性和安全性。

 DESCRIPTION (provided by applicant): Autoimmune diseases are the result of impaired immune tolerance and animal studies indicate that restoring antigen-specific tolerance permanently can constitute a cure. However, this is very challenging to achieve in humans, because they are highly heterogeneous in their genetic and environmental makeup, and the diseases multifactorial. Meanwhile, the incidence of these diseases is on the rise. This heterogeneity may be overcome by targeting multiple biological pathways of tolerance induction, specifically in disease-driving self-reactive T cells, and possibly within strategic tissue sites. Various combinations of drugs, biologics and/or tolerizing antigens have been tested in therapy, but each component acts independently in this case. What is missing is a single "tolerogenic interface" that enables the antigenic and multiple tolerogenic signals to act together and concomitantly on target T cells, resulting in optimal signal integration, and ultimately, optimal reprograming of these self-reactive T cells. The most clinically beneficial outcome is the reprograming into antigen-specific regulatory T cells (Tregs), which are long-lived and have the ability to perpetuate tolerance by suppressing autoimmune responses to other disease-relevant antigens (infectious tolerance). Dendritic cells (DCs), already tested in the treatment of a variet of human diseases, are among the most versatile antigen-presenting cells that can be manipulated for this purpose. However, the creation of customized and complex interfaces consisting of relevant antigens and optimal combinations of tolerogenic signals has not yet been achieved. With this Exploratory/Developmental grant, we propose to engineer new DC-based tolerogenic interfaces whose components are delivered as mixtures of mRNA by electroporation. Under Specific Aim 1, we will test the expression of several antigens and tolerogenic products in this system, and identify combinations that can most efficiently reprogram diabetogenic T cells into Tregs. The major goals are to find signaling pathways that synergize in inducing highly functional and stable Tregs, and to generate Tregs in vivo that are capable of mediating long-lasting protection from disease. Under Specific Aim 2, we will use the same mRNA-based manipulation approach to overexpress specific homing receptors in DCs. The goal is to enhance the migration of tolerogenic DCs to the pancreatic lymph nodes, where diabetogenic T cells are primed, or to the pancreatic islets, where they exert their pathogenic function. DC-based cell therapies have been increasingly tested in clinical trials to treat human disease, mostly cancer, and more recently for autoimmunity. These studies suggest that DCs are devoid of the adverse effects of many drugs and biologics tested to date. The development of tolerogenic DCs that (1) target specific T cells, (2) engage them through multiple biological pathways for efficient reprograming into Tregs and (3) accumulate better and preferentially in relevant tissues will greatly improve both efficacy and safety of cell-based therapies for autoimmune diseases.