使用患者自身T细胞的过继细胞疗法有望成为理想的癌症治疗策略,具有优异的抗肿瘤效果和低副作用。然而,这种靶向实体瘤的疗法不太可能有效,因为肿瘤组织具有抑制T细胞功能的环境.特别是,程序性死亡-1(PD-1)及其配体(PD-L1)之间的相互作用抑制T细胞活化,从而使T细胞消除肿瘤细胞。这里,我们试图开发即使在肿瘤组织中也能发挥有效抗肿瘤活性的T细胞,方法是对它们进行基因修饰,使其表达能够抑制PD-L1/PD-1相互作用的抗PD-L1膜锚定型单链可变片段(M-scFv).抗PD-L1M-scFv可以在T细胞上表达,同时保持PD-L1结合能力。尽管由CD3刺激诱导的T细胞增殖根据PD-L1刺激强度而降低,通过避免PD-L1/PD-1介导的抑制,表达M-scFv的T细胞即使在PD-L1存在下也显示出高增殖活性。此外,表达M-scFv的T细胞对PD-L1高肿瘤细胞的细胞毒活性高于模拟T细胞。当治疗靶点为低抗原性肿瘤细胞,主要组织相容性复合物表达较低时,PD-L1/PD-1阻断的效果更为明显。只呈递共有的抗原.这些结果表明,抗PD-L1M-scFv表达在通过PD-L1/PD-1相互作用避免T细胞功能障碍方面具有功能。因此,与T细胞和抗体的联合治疗相比,我们的抗PD-L1M-scFv表达T细胞的概念有望提高T细胞治疗的功效,并有助于简化治疗系统并降低治疗成本。
Adoptive cell therapy using patients\' own T-cells is expected to be an ideal cancer treatment strategy with excellent antitumor effects and low side effects. However, this therapy targeting solid tumors is unlikely to be effective because tumor tissues have an environment that suppresses T-cell function. In particular, interaction between programmed death-1 (PD-1) and its ligand (PD-L1) inhibits T-cell activation by which T-cells eliminate tumor cells. Here, we attempted to develop T-cells that can exert potent antitumor activity even in tumor tissues by genetically modifying them to express the anti-PD-L1 membrane-anchoring type single chain variable fragment (M-scFv) that can inhibit PD-L1/PD-1 interaction. Anti-PD-L1 M-scFv could be expressed on T-cells while maintaining PD-L1-binding ability. Although T-cell proliferation induced by CD3 stimulation was decreased depending on the PD-L1 stimulation intensity, M-scFv-expressing T-cells showed high proliferative activity even in the presence of PD-L1 by avoiding the PD-L1/PD-1-mediated suppression. Furthermore, M-scFv-expressing T-cells showed higher cytotoxic activity against PD-L1high tumor cells than that of mock T-cells. The effect of PD-L1/PD-1 blockade was more pronounced when the therapeutic target was low-antigenic tumor cells with low major histocompatibility complex expression, presenting only the shared antigen. These results indicated that anti-PD-L1 M-scFv expression was functional in avoiding T-cell dysfunction by PD-L1/PD-1 interaction. Our concept of anti-PD-L1 M-scFv-expressing T-cells is thus expected to improve the efficacy of T-cell therapy and contribute to simplify the treatment system and reduce treatment costs compared with the combination therapy of T-cells and antibodies.