BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.
School of Biomedical Engineering and.
JCI Insight. 2023 Oct 9;8(19):e167215. doi: 10.1172/jci.insight.167215.
Tregs expressing chimeric antigen receptors (CAR-Tregs) are a promising tool to promote transplant tolerance. The relationship between CAR structure and Treg function was studied in xenogeneic, immunodeficient mice, revealing advantages of CD28-encoding CARs. However, these models could underrepresent interactions between CAR-Tregs, antigen-presenting cells (APCs), and donor-specific Abs. We generated Tregs expressing HLA-A2-specific CARs with different costimulatory domains and compared their function in vitro and in vivo using an immunocompetent model of transplantation. In vitro, the CD28-encoding CAR had superior antigen-specific suppression, proliferation, and cytokine production. In contrast, in vivo, Tregs expressing CARs encoding CD28, ICOS, programmed cell death 1, and GITR, but not 4-1BB or OX40, all extended skin allograft survival. To reconcile in vitro and in vivo data, we analyzed effects of a CAR encoding CD3ζ but no costimulatory domain. These data revealed that exogenous costimulation from APCs can compensate for the lack of a CAR-encoded CD28 domain. Thus, Tregs expressing a CAR with or without CD28 are functionally equivalent in vivo, mediating similar extension of skin allograft survival and controlling the generation of anti-HLA-A2 alloantibodies. This study reveals a dimension of CAR-Treg biology and has important implications for the design of CARs for clinical use in Tregs.
表达嵌合抗原受体 (CAR) 的调节性 T 细胞 (Treg) 是促进移植耐受的有前途的工具。研究了异种免疫缺陷小鼠中 CAR 结构与 Treg 功能之间的关系，揭示了编码 CD28 的 CAR 的优势。然而，这些模型可能无法充分代表 CAR-Treg、抗原呈递细胞 (APC) 和供体特异性 Abs 之间的相互作用。我们生成了表达具有不同共刺激结构域的 HLA-A2 特异性 CAR 的 Treg，并使用同种异体移植的免疫活性模型比较了它们在体外和体内的功能。在体外，编码 CD28 的 CAR 具有优越的抗原特异性抑制、增殖和细胞因子产生。相比之下，在体内，表达编码 CD28、ICOS、程序性细胞死亡 1 和 GITR 的 CAR，但不表达 4-1BB 或 OX40 的 Treg，均可延长皮肤同种异体移植物的存活时间。为了协调体外和体内数据，我们分析了编码 CD3ζ 但没有共刺激结构域的 CAR 的作用。这些数据表明，来自 APC 的外源性共刺激可以弥补 CAR 编码的 CD28 结构域的缺乏。因此，表达具有或不具有 CD28 的 CAR 的 Treg 在体内具有相同的功能，介导类似的皮肤同种异体移植物存活时间延长，并控制抗 HLA-A2 同种抗体的产生。这项研究揭示了 CAR-Treg 生物学的一个维度，对 CAR 在 Treg 中的临床应用设计具有重要意义。
