CeGaT GmbH, 72076 Tübingen, Germany; and
CeGaT GmbH, 72076 Tübingen, Germany; and.
J Immunol. 2021 Feb 1;206(3):580-587. doi: 10.4049/jimmunol.2000811. Epub 2020 Dec 9.
Gaining detailed insights into the role of host immune responses in viral clearance is critical for understanding COVID-19 pathogenesis and future treatment strategies. Although studies analyzing humoral immune responses against SARS-CoV-2 were available rather early during the pandemic, cellular immunity came into focus of investigations just recently. For the present work, we have adapted a protocol designed for the detection of rare neoantigen-specific memory T cells in cancer patients for studying cellular immune responses against SARS-CoV-2. Both CD4 and CD8 T cells were detected after 6 d of in vitro expansion using overlapping peptide libraries representing the whole viral protein. The assay readout was an intracellular cytokine staining and flow cytometric analysis detecting four functional markers simultaneously (CD154, TNF, IL-2, and IFN-γ). We were able to detect SARS-CoV-2-specific T cells in 10 of 10 COVID-19 patients with mild symptoms. All patients had reactive T cells against at least 1 of 12 analyzed viral Ags, and all patients had Spike-specific T cells. Although some Ags were detected by CD4 and CD8 T cells, VME1 was mainly recognized by CD4 T cells. Strikingly, we were not able to detect SARS-CoV-2-specific T cells in 18 unexposed healthy individuals. When we stimulated the same samples overnight, we measured significant numbers of cytokine-producing cells even in unexposed individuals. Our comparison showed that the stimulation conditions can profoundly impact the activation readout in unexposed individuals. We are presenting a highly specific diagnostic tool for the detection of SARS-CoV-2-reactive T cells.
深入了解宿主免疫反应在清除病毒中的作用对于理解 COVID-19 的发病机制和未来的治疗策略至关重要。尽管在疫情早期就有分析针对 SARS-CoV-2 的体液免疫反应的研究，但细胞免疫最近才成为研究的焦点。在本研究中，我们对用于检测癌症患者中针对 SARS-CoV-2 的罕见新抗原特异性记忆 T 细胞的方案进行了改编，用于研究针对 SARS-CoV-2 的细胞免疫反应。使用代表整个病毒蛋白的重叠肽文库，在体外扩增 6 天后检测 CD4 和 CD8 T 细胞。该检测方法的读取结果是细胞内细胞因子染色和流式细胞术分析，同时检测四个功能标志物（CD154、TNF、IL-2 和 IFN-γ）。我们能够在 10 名有轻症 COVID-19 症状的患者中检测到 SARS-CoV-2 特异性 T 细胞。所有患者均对 12 种分析的病毒抗原中的至少 1 种产生反应性 T 细胞，且所有患者均有 Spike 特异性 T 细胞。尽管一些抗原可被 CD4 和 CD8 T 细胞识别，但 VME1 主要被 CD4 T 细胞识别。引人注目的是，我们未能在 18 名未接触过 SARS-CoV-2 的健康个体中检测到 SARS-CoV-2 特异性 T 细胞。当我们将相同的样本刺激过夜时，即使在未接触过 SARS-CoV-2 的个体中，我们也能测量到大量产生细胞因子的细胞。我们的比较表明，刺激条件会对未接触过 SARS-CoV-2 的个体的激活读数产生深远影响。我们提出了一种用于检测 SARS-CoV-2 反应性 T 细胞的高度特异性诊断工具。
