SARS-CoV-2-specific T cells exhibit phenotypic features reflecting helper function, lack of terminal differentiation, and high proliferation potential

Convalescing COVID-19 patients mount robust T cell responses against SARS-CoV-2, suggesting an important role for T cells in viral clearance. To date, the phenotypes of SARS-CoV-2-specific T cells remain poorly defined. Using 38-parameter CyTOF, we phenotyped longitudinal specimens of SARS-CoV-2-specific CD4+ and CD8+ T cells from nine individuals who recovered from mild COVID-19. SARS-CoV-2-specific CD4+ T cells were exclusively Th1 cells, and predominantly Tcm with phenotypic features of robust helper function. SARS-CoV-2-specific CD8+ T cells were predominantly Temra cells in a state of less terminal differentiation than most Temra cells. Subsets of SARS-CoV-2-specific T cells express CD127, can homeostatically proliferate, and can persist for over two months. Our results suggest that long-lived and robust T cell immunity is generated following natural SARS-CoV-2 infection, and support an important role for SARS-CoV-2-specific T cells in host control of COVID-19.新型冠状病毒肺炎（COVID-19）康复患者可针对新型冠状病毒（SARS-CoV-2）产生强效T细胞应答，提示T细胞在病毒清除过程中发挥关键作用。截至目前，新型冠状病毒特异性T细胞的表型特征仍未得到充分阐明。本研究采用38参数飞行时间质谱流式细胞术（CyTOF），对9名轻症新型冠状病毒肺炎康复者的纵向样本中的新型冠状病毒特异性CD4+ T细胞与CD8+ T细胞进行了表型分析。新型冠状病毒特异性CD4+ T细胞均为Th1细胞，且主要为具备强效辅助功能表型特征的中央记忆性T细胞（Tcm）。新型冠状病毒特异性CD8+ T细胞则以终末分化效应记忆T细胞（Temra）为主，其终末分化程度低于多数同类T细胞亚群。部分新型冠状病毒特异性T细胞亚群可表达CD127，具备稳态增殖能力，并可在体内存活超过两个月。本研究结果表明，自然感染新型冠状病毒后可诱导产生长效且强效的T细胞免疫，并支持新型冠状病毒特异性T细胞在宿主控制新型冠状病毒肺炎感染过程中发挥关键作用。