Molecular and Cellular Immunology Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.
Cell Communication Lab, Department of Oncology, University College London Cancer Institute, London, United Kingdom.
Blood Adv. 2023 May 9;7(9):1725-1738. doi: 10.1182/bloodadvances.2022008490.
We recently described a low-affinity second-generation CD19 chimeric antigen receptor (CAR) CAT that showed enhanced expansion, cytotoxicity, and antitumor efficacy compared with the high-affinity (FMC63-based) CAR used in tisagenlecleucel, in preclinical models. Furthermore, CAT demonstrated an excellent toxicity profile, enhanced in vivo expansion, and long-term persistence in a phase 1 clinical study. To understand the molecular mechanisms behind these properties of CAT CAR T cells, we performed a systematic in vitro characterization of the transcriptomic (RNA sequencing) and protein (cytometry by time of flight) changes occurring in T cells expressing low-affinity vs high-affinity CD19 CARs following stimulation with CD19-expressing cells. Our results show that CAT CAR T cells exhibit enhanced activation to CD19 stimulation and a distinct transcriptomic and protein profile, with increased activation and cytokine polyfunctionality compared with FMC63 CAR T cells. We demonstrate that the enhanced functionality of low-affinity CAT CAR T cells is a consequence of an antigen-dependent priming induced by residual CD19-expressing B cells present in the manufacture.
我们最近描述了一种低亲和力第二代 CD19 嵌合抗原受体 (CAR) CAT，与 tisagenlecleucel 中使用的高亲和力 (基于 FMC63 的) CAR 相比，它在临床前模型中显示出增强的扩增、细胞毒性和抗肿瘤功效。此外，CAT 在一项 1 期临床研究中表现出良好的毒性特征、增强的体内扩增和长期持久性。为了了解 CAT CAR T 细胞这些特性背后的分子机制，我们对表达低亲和力和高亲和力 CD19 CAR 的 T 细胞在受到表达 CD19 的细胞刺激后发生的转录组学（RNA 测序）和蛋白质（飞行时间流式细胞术）变化进行了系统的体外表征。我们的结果表明，与 FMC63 CAR T 细胞相比，CAT CAR T 细胞对 CD19 刺激表现出增强的激活，并且具有独特的转录组和蛋白质特征，表现为激活和细胞因子多功能性增加。我们证明，低亲和力 CAT CAR T 细胞的增强功能是制造过程中存在的残留表达 CD19 的 B 细胞诱导的抗原依赖性启动的结果。
