Ling Ni, Fang Ye, Meng-Li Cheng, Yu Feng, Yong-Qiang Deng, Hui Zhao, Peng Wei, Jiwan Ge, Mengting Gou, Xiaoli Li, Lin Sun, Tianshu Cao, Pengzhi Wang, Chao Zhou, Rongrong Zhang, Peng Liang, Han Guo, Xinquan Wang, Cheng-Feng Qin, Fang Chen, Chen Dong
The World Health Organization has declared SARS-CoV-2 virus outbreak a world-wide 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 8 newly discharged patients. Follow-up analysis on another cohort of 6 patients 2 weeks post discharge also revealed high titers of 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 has also implications in developing an effective vaccine to SARS-CoV-2 infection.