Bi-functional fusion proteins to regulate autoimmunity

目前针对自身免疫性疾病的治疗方法是不充分的，因为它们治疗的是症状，而不是潜在的 原因，并经常与严重的副作用，特别是在长期使用。调节性T细胞 (Treg)是主动抑制自身反应性T细胞的主要机制，在ALL中存在 个人。Tregs的崩溃导致自身反应性T细胞的激活，这有助于T细胞的发育 自身免疫力的问题。相应地，一种有吸引力的治疗方法是重新调节免疫系统以 增加Tregs的数量和/或功能，以限制自身反应性T细胞。我实验室的大量工作已经完成 证实IL-2对Treg的发育和外周动态平衡是必不可少的。此外，我们还展示了 低IL-2R信号很容易支持Treg的关键IL-2R依赖活性，但不支持T效应 (被盖)细胞。这些发现为使用低剂量重组IL-2(rIL-2)的概念提供了机制支持。 作为自身免疫的Treg选择性疗法。最近对几种自身免疫性疾病的临床试验表明 小剂量的rIL-2选择性地提高了Tregs，这通常伴随着临床上的改善。不过， RIL-2的药代动力学和药效学较差，需要频繁给药。 此外，自身免疫相关症状并未完全缓解，并且在停止低剂量治疗后 RIL-2，自身免疫攻击通常恢复。基于IL-2的新型分子工程生物制品已经问世 与重组IL-2(rIL-2)相比，其性能有所改善。在这方面，我们 开发了一种基于IL-2的蛋白质，其中IL-2与CD25相连。IL-2/CD25融合蛋白选择性地显示 对于Tregs，在扩大Tregs和限制NOD小鼠糖尿病方面比rIL-2有效得多。 然而，即使有了这种基于IL-2的生物递送IL-2活性的改进，糖尿病的发生 有时只是耽搁了。基于这些发现，我们假设组合策略将是 有必要增强小剂量IL-2的疗效。我们希望调查的一种方法是增加 Tregs通过IL-2同时应用免疫调节增强免疫抑制 活动。为了实现这一目标，我们开发了一种双功能融合蛋白来传递这两种活性。 因此，本提案的主要目的是优化和评价该融合蛋白在体内的活性。 通过以下具体目标。1)评估这种双功能融合蛋白是否比 MIL-2/CD25限制临床前结肠炎和糖尿病小鼠模型的自身免疫。2)确定 该双功能融合蛋白的细胞作用机制。这些研究测试了这种新型融合的程度 蛋白质直接限制TEF细胞，并影响自身免疫攻击组织部位的其他免疫细胞(S)。3)至 评价双功能融合蛋白对自身反应性T细胞的作用。

Current therapies are for autoimmune diseases are inadequate as they treat symptoms, not the underlying cause, and are often associated with severe sides effects, especially upon prolonged use. Regulatory T cells (Tregs) represent a major mechanism to actively suppress self-reactive T cells, which are present in all individuals. A breakdown in Tregs leads to activation of self-reactive T cells that contribute to the development of autoimmunity. Correspondingly, an attractive therapeutic approach is to re-regulate the immune system to boost the numbers and/or function of Tregs to limit autoreactive T cells. Extensive work from my lab has established that IL-2 is essential for Treg development and peripheral homeostasis. Furthermore, we showed that key IL-2R-dependent activities were readily supported by low IL-2R signaling in Treg but not T effector (Teff) cells. These findings provide mechanistic support for the notion to use low-dose recombinant IL-2 (rIL-2) as a Treg-selective therapy for autoimmunity. Recent clinical trials across several autoimmune diseases show that low-dose rIL-2 selectively boost Tregs that is often accompanied by clinical improvement. Nevertheless, rIL-2 has poor pharmacokinetics and pharmacodynamics that necessitate frequent administration. Furthermore, autoimmune-related symptoms were not completely resolved, and upon cessation of low-dose rIL-2, the autoimmune-attack usually resumed. New molecularly engineered IL-2-based biologics have been developed that have improved properties when compared to recombinant IL-2 (rIL-2). In this regard, we developed an IL-2-based protein, where IL-2 is linked to CD25. The IL-2/CD25 fusion protein shows selectively toward Tregs and is much more effective than rIL-2 in expanding Tregs and limiting diabetes in NOD mice. However, even with this improved IL-2-based biologic to deliver IL-2 activity, diabetes development was sometimes only delayed. Based on these findings, we have hypothesized that combination strategies will be necessary to enhance the efficacy of low-dose IL-2. One approach that we wish to investigate is to increase Tregs through IL-2 while enhancing immunosuppress by simultaneously applying an immune regulating activity. To accomplish this goal, we have developed a bifunctional fusion protein to deliver these two activities. Thus, the main objective of this proposal is to optimize and evaluate the activities of this fusion protein in vivo through the following specific aims. 1) To assess whether this bifunctional fusion protein is more effective than mIL-2/CD25 to limit autoimmunity in pre-clinical mouse models of colitis and diabetes. 2) To determine the cellular mechanism of action of this bifunctional fusion protein. These studies test the extent this novel fusion protein directly limits Teff cells and affects other immune cells in the tissue site(s) of autoimmune attack. 3) To evaluate the contribution of the bifunctional fusion protein on autoreactive T cells.