Department of Microbiology, Dokkyo Medical University School of Medicine, Tochigi 321-0293, Japan.
Int J Mol Sci. 2024 Aug 8;25(16):8662. doi: 10.3390/ijms25168662.
Improving chimeric antigen receptor (CAR)-T cell therapeutic outcomes and expanding its applicability to solid tumors requires further refinement of CAR-T cells. We previously reported that CAR-T cells bearing a herpes virus entry mediator (HVEM)-derived co-stimulatory signal domain (CSSD) (HVEM-CAR-T cells) exhibit superior functions and characteristics. Here, we conducted comparative analyses to evaluate the impact of different CSSDs on CAR-T cell exhaustion. The results indicated that HVEM-CAR-T cells had significantly lower frequencies of exhausted cells and exhibited the highest proliferation rates upon antigenic stimulation. Furthermore, proliferation inhibition by programmed cell death ligand 1 was stronger in CAR-T cells bearing CD28-derived CSSD (CD28-CAR-T cells) whereas it was weaker in HVEM-CAR-T. Additionally, HVEM-CAR-T cells maintained a low exhaustion level even after antigen-dependent proliferation and exhibited potent killing activities, suggesting that HVEM-CAR-T cells might be less prone to early exhaustion. Analysis of CAR localization on the cell surface revealed that CAR formed clusters in CD28-CAR-T cells whereas uniformly distributed in HVEM-CAR-T cells. Analysis of CD3ζ phosphorylation indicated that CAR-dependent tonic signals were strongly sustained in CD28-CAR-T cells whereas they were significantly weaker in HVEM-CAR-T cells. Collectively, these results suggest that the HVEM-derived CSSD is useful for generating CAR-T cells with exhaustion-resistant properties, which could be effective against solid tumors.
为了提高嵌合抗原受体（CAR）-T 细胞治疗效果，并将其应用扩展到实体瘤，需要对 CAR-T 细胞进行进一步的改进。我们之前报道过，携带疱疹病毒进入介质（HVEM）衍生的共刺激信号结构域（CSSD）的 CAR-T 细胞（HVEM-CAR-T 细胞）具有更优越的功能和特性。在这里，我们进行了比较分析，以评估不同 CSSD 对 CAR-T 细胞耗竭的影响。结果表明，HVEM-CAR-T 细胞中耗尽细胞的频率明显较低，在抗原刺激下表现出最高的增殖率。此外，在携带 CD28 衍生 CSSD 的 CAR-T 细胞（CD28-CAR-T 细胞）中，程序性细胞死亡配体 1 的增殖抑制作用更强，而在 HVEM-CAR-T 细胞中则较弱。此外，HVEM-CAR-T 细胞即使在抗原依赖性增殖后仍保持低耗竭水平，并表现出强大的杀伤活性，表明 HVEM-CAR-T 细胞可能不易早期耗竭。CAR 在细胞表面的定位分析表明，CAR 在 CD28-CAR-T 细胞中形成簇，而在 HVEM-CAR-T 细胞中均匀分布。CD3ζ 磷酸化分析表明，CD28-CAR-T 细胞中强烈持续地维持着 CAR 依赖性的紧张信号，而在 HVEM-CAR-T 细胞中则显著较弱。总之，这些结果表明，HVEM 衍生的 CSSD 可用于产生具有抗耗竭特性的 CAR-T 细胞，这可能对实体瘤有效。
