Detection of SARS-CoV-2-specific humoral and cellular immunity in COVID-19 convalescent individuals

Ni, Ling; Ye, Fang; Cheng, Meng-Li; Feng, Yu; Deng, Yong-Qiang; Zhao, Hui; Wei, Peng; Ge, Jiwan; Gou, Mengting; Li, Xiaoli; Sun, Lin; Cao, Tianshu; Wang, Pengzhi; Zhou, Chao; Zhang, Rongrong; Liang, Peng; Guo, Han; Wang, Xinquan; Qin, Cheng-Feng; Chen, Fang; Dong, Chen

Summary 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.