Department of Immunology, Roswell Park Comprehensive Cancer Center, Buffalo, New York.
Department of Internal Medicine, Roswell Park Comprehensive Cancer Center, Buffalo, New York.
Cancer Immunol Res. 2021 Jul;9(7):790-810. doi: 10.1158/2326-6066.CIR-20-0922. Epub 2021 May 14.
T-cell activation and expansion in the tumor microenvironment (TME) are critical for antitumor immunity. Neutrophils in the TME acquire a complement-dependent T-cell suppressor phenotype that is characterized by inhibition of T-cell proliferation and activation through mechanisms distinct from those of myeloid-derived suppressor cells. In this study, we used ascites fluid supernatants (ASC) from patients with ovarian cancer as an authentic component of the TME to evaluate the effects of ASC on neutrophil function and mechanisms for neutrophil-driven immune suppression. ASC prolonged neutrophil life span, decreased neutrophil density, and induced nuclear hypersegmentation. Mass cytometry analysis showed that ASC induced 15 distinct neutrophil clusters. ASC stimulated complement deposition and signaling in neutrophils, resulting in surface mobilization of granule constituents, including NADPH oxidase. NADPH oxidase activation and phosphatidylserine signaling were required for neutrophil suppressor function, although we did not observe a direct role of extracellular reactive oxygen species in inhibiting T-cell proliferation. Postoperative surgical drainage fluid also induced a complement-dependent neutrophil suppressor phenotype, pointing to this effect as a general response to injury. Like circulating lymphocytes, ASC-activated neutrophils caused complement-dependent suppression of tumor-associated lymphocytes. ASC-activated neutrophils adhered to T cells and caused trogocytosis of T-cell membranes. These injury and signaling cues resulted in T-cell immunoparalysis characterized by impaired NFAT translocation, IL2 production, glucose uptake, mitochondrial function, and mTOR activation. Our results demonstrate that complement-dependent priming of neutrophil effector functions in the TME induces a T-cell nonresponsiveness distinct from established checkpoint pathways and identify targets for immunotherapy.
T 细胞在肿瘤微环境（TME）中的激活和扩增对于抗肿瘤免疫至关重要。TME 中的中性粒细胞获得一种补体依赖性 T 细胞抑制表型，其特征是通过与髓系来源的抑制细胞不同的机制抑制 T 细胞增殖和激活。在这项研究中，我们使用卵巢癌患者的腹水上清液（ASC）作为 TME 的真实成分，来评估 ASC 对中性粒细胞功能的影响及其驱动免疫抑制的机制。ASC 延长了中性粒细胞的寿命，降低了中性粒细胞的密度，并诱导核过度分裂。质谱细胞术分析显示，ASC 诱导了 15 个不同的中性粒细胞簇。ASC 刺激中性粒细胞中补体的沉积和信号转导，导致颗粒成分（包括 NADPH 氧化酶）的表面动员。NADPH 氧化酶的激活和磷脂酰丝氨酸信号转导是中性粒细胞抑制功能所必需的，尽管我们没有观察到细胞外活性氧在抑制 T 细胞增殖中的直接作用。术后手术引流液也诱导了一种补体依赖性中性粒细胞抑制表型，这表明这种效应是对损伤的一般反应。与循环淋巴细胞一样，ASC 激活的中性粒细胞导致肿瘤相关淋巴细胞的补体依赖性抑制。ASC 激活的中性粒细胞黏附于 T 细胞并导致 T 细胞膜的 trogocytosis。这些损伤和信号提示导致 T 细胞免疫麻痹，其特征为 NFAT 易位、IL2 产生、葡萄糖摄取、线粒体功能和 mTOR 激活受损。我们的结果表明，TME 中补体依赖性中性粒细胞效应功能的启动诱导了一种与已建立的检查点途径不同的 T 细胞无反应性，并确定了免疫治疗的靶点。
