The role of CAR-expressing Tregs on antigen-specific immune suppression

项目摘要 调节性T细胞（Tcells）是T细胞的一个关键亚群，其对于调节免疫调节是重要的。 适应性免疫反应在Scurfy中观察到的Foxp 3基因的功能缺失突变 免疫失调、多内分泌病和X连锁 （IPEX）综合征，导致全身性和致命性T细胞依赖性淋巴增生性疾病， 从而强调了TGFAP在维持免疫稳态中的重要性。鉴于 免疫球蛋白在限制过度的免疫反应，理解免疫球蛋白的生物学特性， 驱动Treg功能和扩增的信号是关键，特别是在自身免疫和移植中， 在这些环境中，TdR的调节可能有利于这些疾病状态的解决。 我们实验室以前发表的工作表明，TCR信号传导是至关重要的， 用于维持最佳的Treg抑制功能和增殖。除了TCR介导的 信号，我们的实验室已经表明，共刺激在调节Treg扩增中也很重要， 和坚持。 虽然对驱动Treg生物学的分子线索的深入了解已经慢慢出现， 利用这些线索，利用TdR作为一种潜在的治疗慢性 炎性疾病仍然构成重大挑战。扩增多克隆TcR， 在小鼠模型中显示改善自身免疫，抑制不是抗原- 特定.此外，选择性地提供共刺激信号在技术上具有挑战性 只对Tcons说不对Tcons说 该提案的主要目标是利用嵌合抗原受体（CAR）赋予 Treg具有抗原特异性，并通过添加 共刺激结构域。我们将鉴定是否转导了CD 19-的T细胞 CAR与Foxp 3（CART 19-Foxp 3）结合将抑制抗原特异性常规T细胞 细胞（Tconv）以B细胞依赖性方式增殖，而不通过CD 19特异性杀伤B细胞， CART 19-Foxp 3细胞。此外，我们还将确定共刺激因子的存在如何影响细胞的功能。 CAR构建体中的结构域影响CART 19-Foxp 3功能、持久性和扩增。 此外，我们将确定CART 19-Foxp 3细胞是否可以反过来抑制B细胞 通过调节常规T细胞活化，在体内产生免疫应答，如抗体产生。 在这一目标的研究的进一步应用将扩大到确定潜在的 CART-Foxp 3细胞在治疗狼疮样模型中观察到的慢性炎症中的治疗用途 慢性移植物抗宿主病（GVHD）依赖于B细胞产生自身抗体。 通过拟议的研究计划，我们将提供CAR- 表达Tcl 3以抗原特异性方式抑制免疫应答，这可能是 用作治疗炎性病症的新治疗策略。

Project Summary Regulatory T cells (Tregs) are a key subset of T cells important for the regulation of adaptive immune responses. Loss of function mutations in the Foxp3 gene, as seen in Scurfy murine strains and humans with immune dysregulation, polyendocrinopathy, and X-linked (IPEX) syndrome, lead to a systemic and fatal T cell-dependent lymphoproliferative disease, thus emphasizing the importance of Tregs in maintaining immune homeostasis. Given that Tregs are important in limiting overexcessive immune responses, understanding the biological signals that drive Treg function and expansion is key, especially in autoimmune and transplant settings in which modulation of Tregs could be beneficial for resolution of those disease states. Previously published work from our laboratory has shown that TCR signaling is critical for maintaining optimal Treg suppressive function and proliferation. In addition to TCR-mediated signals, our lab has shown that co-stimulation is also important in modulation of Treg expansion and persistence. While insight into the molecular cues that drive Treg biology has been slowly emerging, harnessing these cues to utilize Tregs as a potential therapy for the treatment of chronic inflammatory diseases still poses significant challenges. The expansion of polyclonal Tregs has been shown to ameliorate autoimmunity in mouse model, the suppression is not antigen- specific. Furthermore, it is technically challenging to selectively provide co-stimulatory signals only to Tregs and not to Tconvs. The main goal of this proposal is to utilize chimeric antigen receptors (CAR) to endow Treg with antigen specificity and enhance Treg function and expansion through the addition of co-stimulatory domains in the constructs. We will identify whether T cells transduced with CD19- CAR in conjunction with Foxp3 (CART19-Foxp3) will suppress antigen-specific conventional T cell (Tconv) proliferation in a B cell-dependent manner without CD19-specific killing of B cells by CART19-Foxp3 cells. Additionally, we will determine how the presence of co-stimulatory domains in the CAR construct influences CART19-Foxp3 function, persistence, and expansion. Furthermore, we will determine whether CART19-Foxp3 cells can, in turn, suppress B cell responses, such as antibody production, in vivo by modulation of conventional T cell activation. Further application of the studies in this aim will be extended to identifying the potential therapeutic use of CART-Foxp3 cells in treating chronic inflammation seen in a lupus-like model of chronic graft versus host (GVHD) that is dependent on autoantibody production by B cells. Through the proposed research plan, we will provide proof-of-principle that CAR- expressing Tregs suppress immune responses in an antigen-specific manner, which could be used as a novel therapeutic strategy for treatment of inflammatory conditions.