Immunomodulation Requirements for Treg Immunotherapy for autoimmune diabetes

描述(申请人提供)：我们的工作重点是T调节(Treg)细胞，它抑制自身和同种异体免疫反应，使这些细胞具有吸引力的新的基于细胞的治疗方法，以促进耐受性和控制自身免疫性疾病，包括1型糖尿病。然而，由于无法产生足够数量的细胞来抑制所需的免疫反应(S)并实现捐赠者Treg细胞接种的稳定植入，这些细胞用于治疗受到阻碍。此外，胸腺不断产生Treg细胞会产生一种持续的竞争性障碍，我们的实验室已经证明，为了成功地将Treg细胞用于治疗，必须克服这一障碍。我们实验室以前的研究表明，将Treg细胞单一过继转移到新生的IL-2R？/-小鼠中，这会损害IL-2信号和Treg细胞功能，完全可以防止严重的自身免疫，否则这些小鼠在几周内就会死亡。野生型Treg细胞的治疗使这些小鼠保持无自身免疫状态，并拥有正常的寿命，并伴随着终身捐赠者Treg细胞的植入。重要的是，我们发现异体Treg细胞也能移植给皮肤移植物并恢复自身耐受性。这些发现表明，在正确的生物学基础上 条件采用转移，即使是少量的，未经处理的Treg细胞在获得耐受性和结果长期植入方面是非常有效的。这个IL-2R-/-模型为成功治疗可能需要的机制提供了一些线索。这项建议的总体目标是：1)阐明调节成功的Treg疗法的机制；2)开发治疗T1D的临床可翻译方案，使用临床前模型来研究是否可以实现临床适用的Treg疗法来预防或逆转T1D。 自身免疫性糖尿病或抑制移植物排斥反应的胰岛细胞移植治疗糖尿病。目前的研究方案旨在验证这样一种假设，即稳定的供体Treg植入需要免疫调节，以及体内存在通过抗原进行生物选择的治疗性Treg，从而导致成功的免疫治疗。基于这一假设，该方案的具体目的是：1)通过临床可翻译的组合方案的免疫调节，确定促进稳定供体Treg在NOD小鼠体内植入的机制。2)确定CD3和Treg输注后是否发生抗原(Ag)特异性供体Tregs的选择和扩增。这项研究将产生基于Treg细胞的成功疗法设计所需的新数据。此外，与已经或正在用于新发糖尿病的临床试验的药物的治疗协同作用的展示，将为未来临床试验的设计提供动力和所需的临床前数据，这些临床试验将过继Treg转移与免疫调节相结合，可能还包括抗原特异性治疗。

DESCRIPTION (provided by applicant): Our work focuses on T regulatory (Treg) cells, which inhibit both self and allogeneic immune responses making these cells attractive for novel cell-based therapy approaches to promote tolerance and control autoimmune diseases, including type 1 diabetes. However, the use of these cells for therapy is hindered by the inability to generate the sufficient number of cells required to inhibit the desired immune response(s) and achieve stable engraftment of the donor Treg cell inoculums. Furthermore, the constant production of Treg cells from the thymus creates a continuous, competitive barrier that our laboratory has demonstrated must be overcome in order to successfully use Treg cells for therapy. Previous studies from our laboratory demonstrate that the single adoptive transfer of Treg cells into neonatal IL-2R¿-/- mice, which have impaired IL-2 signaling and Treg cell function, fully prevents severe autoimmunity that would otherwise be lethal for these mice in a matter of a few weeks. Therapy with wild-type Treg cells allows these mice to remain autoimmune-free and to have a normal life span, and is accompanied by life-long donor Treg cell engraftment. Importantly, we show that allo-Treg cells also engraft which confers tolerance to skin allografts and restores self-tolerance. These findings show that under the right biological conditions adoptive transfer of even a small, unmanipulated number of Treg cells is very effective at achieving tolerance and results in long-term engraftment. This IL-2R¿-/- model offers some clues to the mechanisms that may be required for successful therapy. The overall goals of this proposal are: 1) to elucidate the mechanisms that regulate successful Treg therapy and 2) to develop clinically translatable protocols for the treatment of T1D, using preclinical models to investigate if clinically applicable Treg therapy can be achieved for the prevention or reversal of autoimmune diabetes or to suppress graft rejection of islet cell transplantation for the treatment of diabetes. The present research proposal is designed to test the hypothesis that stable donor Treg engraftment requires immunomodulation and that there is in vivo biological selection by antigen for therapeutic Tregs leading to successful immunotherapy. Based on this hypothesis, the specific aims of this proposal are: 1) to identify mechanisms that promote stable donor Treg engraftment in NOD mice through immunomodulation with clinically translatable combinatorial regimens. and 2) to determine whether selection and expansion of antigen (Ag)-specific donor Tregs occurs following aCD3 and Treg infusion. This research will generate novel data that are required for the design of successful therapies based on Treg cells. Further, the demonstration of therapeutic synergy with agents that have been or are being used in clinical trials for new onset diabetes will provide impetus and needed pre-clinical data for the design of future clinical trials that combine adoptive Treg transfer with immunomodulation, and perhaps antigen-specific therapies.