Department of Immunology, Weizmann Institute of Science, Rehovot, 76100, Israel.
The Mantoux Bioinformatics Institute of the Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot, 76100, Israel.
Cell Rep. 2017 Sep 12;20(11):2547-2555. doi: 10.1016/j.celrep.2017.08.071.
Cytotoxic T lymphocytes (CTLs) used in immunotherapy are typically cultured under atmospheric O pressure but encounter hypoxic conditions inside tumors. Activating CTLs under hypoxic conditions has been shown to improve their cytotoxicity in vitro, but the mechanism employed and the implications for immunotherapy remain unknown. We activated and cultured OT-I CD8 T cells at either 1% or 20% O. Hypoxic CTLs survived, as well as normoxic ones, in vitro but killed OVA-expressing B16 melanoma cells more efficiently. Hypoxic CTLs contained similar numbers of cytolytic granules and released them as efficiently but packaged more granzyme-B in each granule without producing more perforin. We imaged CTL distribution and motility inside B16-OVA tumors using confocal and intravital 2-photon microscopy and observed no obvious differences. However, mice treated with hypoxic CTLs exhibited better tumor regression and survived longer. Thus, hypoxic CTLs may perform better in tumor immunotherapy because of higher intrinsic cytotoxicity rather than improved migration inside tumors.
细胞毒性 T 淋巴细胞（CTL）在免疫疗法中通常在大气氧压力下培养，但在肿瘤内部会遇到缺氧条件。已经证明在缺氧条件下激活 CTL 可以提高其在体外的细胞毒性，但用于激活 CTL 的机制以及对免疫疗法的影响仍不清楚。我们在 1%或 20%氧的条件下激活和培养 OT-I CD8 T 细胞。在体外，缺氧 CTL 和常氧 CTL 都能存活，但能更有效地杀死表达 OVA 的 B16 黑色素瘤细胞。缺氧 CTL 含有相似数量的细胞毒性颗粒，并能同样有效地释放它们，但每个颗粒中包装的颗粒酶-B 更多，而不会产生更多的穿孔素。我们使用共聚焦和活体双光子显微镜对 B16-OVA 肿瘤内 CTL 的分布和运动进行了成像，没有观察到明显的差异。然而，用缺氧 CTL 治疗的小鼠表现出更好的肿瘤消退和更长的存活时间。因此，缺氧 CTL 在肿瘤免疫疗法中可能表现更好，因为其内在的细胞毒性更高，而不是在肿瘤内迁移能力的提高。
