调节性 T 细胞 (Treg) 对免疫稳态做出了重要贡献。由于 Treg 功能障碍可导致同种免疫和自身免疫，因此人们有兴趣通过 Treg 过继转移来纠正这些疾病。临床部署 Treg 细胞疗法的两个主要挑战是确保表型稳定性和最大化效力。在这里，我们描述了一种通过在合成叉头框 P3 (FOXP3) 启动子控制下创建 OX40 配体 (OX40L) 特异性嵌合抗原受体 (CAR)-Treg 来解决这两个问题的方法。这些 CAR-Tr​​eg 的创建通过 OX40L 的参与实现了选择性 Treg 刺激，OX40L 是同种免疫中的关键激活抗原，包括移植物抗宿主病和实体器官移植排斥，以及自身免疫，包括类风湿性关节炎、系统性硬化症和系统性狼疮红斑狼疮。我们证明，OX40L-CAR-Tr​​eg 在表达 OX40L 的细胞存在时被强烈激活，导致 Treg 抑制蛋白上调，而不诱导促炎细胞因子的产生。与对照Tregs相比，OX40L-CAR-Tr​​egs在体外更有效地抑制同种异体反应性T细胞增殖，并且直接抑制活化的单核细胞衍生的树突状细胞（DC）。我们发现 trogocytosis 是这些 CAR-Tr​​eg 有效减少 OX40L 细胞外展示的核心机制之一，从而导致 DC 刺激能力下降。与对照Tregs相比，OX40L-CAR-Tr​​egs表现出增强的控制异种移植物抗宿主病的能力，且不消除移植物抗白血病效应。这些结果表明 OX40L-CAR-Tr​​egs 作为控制同种免疫性疾病和自身免疫性疾病的有效细胞疗法可能具有广泛的适用性。

Regulatory T cells (Tregs) make major contributions to immune homeostasis. Because Treg dysfunction can lead to both allo- and autoimmunity, there is interest in correcting these disorders through Treg adoptive transfer. Two of the central challenges in clinically deploying Treg cellular therapies are ensuring phenotypic stability and maximizing potency. Here, we describe an approach to address both issues through the creation of OX40 ligand (OX40L)-specific chimeric antigen receptor (CAR)-Tregs under the control of a synthetic forkhead box P3 (FOXP3) promoter. The creation of these CAR-Tregs enabled selective Treg stimulation by engagement of OX40L, a key activation antigen in alloimmunity, including both graft-versus-host disease and solid organ transplant rejection, and autoimmunity, including rheumatoid arthritis, systemic sclerosis, and systemic lupus erythematosus. We demonstrated that OX40L-CAR-Tregs were robustly activated in the presence of OX40L-expressing cells, leading to up-regulation of Treg suppressive proteins without induction of proinflammatory cytokine production. Compared with control Tregs, OX40L-CAR-Tregs more potently suppressed alloreactive T cell proliferation in vitro and were directly inhibitory toward activated monocyte-derived dendritic cells (DCs). We identified trogocytosis as one of the central mechanisms by which these CAR-Tregs effectively decrease extracellular display of OX40L, resulting in decreased DC stimulatory capacity. OX40L-CAR-Tregs demonstrated an enhanced ability to control xenogeneic graft-versus-host disease compared with control Tregs without abolishing the graft-versus-leukemia effect. These results suggest that OX40L-CAR-Tregs may have wide applicability as a potent cellular therapy to control both allo- and autoimmune diseases.