The World Health Organization has declared SARS-CoV-2 virus outbreak a worldwide pandemic. However, there is very limited understanding on the immune responses, especially adaptive immune responses to SARS-CoV-2 infection. Here, we collected blood from COVID-19 patients who have recently become virus-free, and therefore were discharged, and detected SARS-CoV-2-specific humoral and cellular immunity in eight newly discharged patients. Follow-up analysis on another cohort of six patients 2 weeks post discharge also revealed high titers of immunoglobulin G (IgG) antibodies. In all 14 patients tested, 13 displayed serum-neutralizing activities in a pseudotype entry assay. Notably, there was a strong correlation between neutralization antibody titers and the numbers of virus-specific T cells. Our work provides a basis for further analysis of protective immunity to SARS-CoV-2, and understanding the pathogenesis of COVID-19, especially in the severe cases. It also has implications in developing an effective vaccine to SARS-CoV-2 infection.

世界卫生组织已宣布SARS-CoV-2病毒爆发为全球大流行。然而，对免疫应答，特别是对SARS-CoV-2感染的适应性免疫应答的了解非常有限。在这里，我们从最近无病毒并因此出院的COVID-19患者中收集了血液，并在八名新出院的患者中检测到SARS-CoV-2特异性的体液和细胞免疫。出院后2周对另一名6名患者的队列研究也显示出高滴度的免疫球蛋白G（IgG）抗体。在所有接受测试的14位患者中，有13位在假型进入分析中显示出血清中和活性。值得注意的是，中和抗体滴度与病毒特异性T细胞数量之间存在很强的相关性。我们的工作为进一步分析针对SARS-CoV-2的保护性免疫，并了解COVID-19的发病机理（尤其是在严重病例中）提供了基础。它还对开发针对SARS-CoV-2感染的有效疫苗具有影响。