Immune memory in convalescent patients with asymptomatic or mild COVID-19
Quanxin Long, Yanjun Jia, Xin Wang, Haijun Deng, Xiaoxia Cao, Jun Yuan, Liang Fang, Xu-Rong Cheng, Chao Luo, An-Ran He, Xiaojun Tang, Jieli Hu, Yuan Hu, Ni Tang, Xue-Fei Cai, Deqiang Wang, Jie Hu, Jingfu Qiu, Beizhong Liu, Juan Chen, Ailong Huang
Abstract
It is important to evaluate the durability of the protective immune response elicited by primary infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we systematically evaluated the SARS-CoV-2-specific memory B cell and T cell responses in healthy controls and individuals recovered from asymptomatic or symptomatic infection approximately 6 months prior. Comparatively low frequencies of memory B cells specific for the receptor-binding domain (RBD) of spike glycoprotein (S) persisted in the peripheral blood of individuals who recovered from infection (median 0.62%, interquartile range 0.48-0.69). The SARS-CoV-2 RBD-specific memory B cell response was detected in 2 of 13 individuals who recovered from asymptomatic infection and 10 of 20 individuals who recovered from symptomatic infection. T cell responses induced by S, membrane (M), and nucleocapsid (N) peptide libraries from SARS-CoV-2 were observed in individuals recovered from coronavirus disease 2019 (COVID-19), and cross-reactive T cell responses to SARS-CoV-2 were also detected in healthy controls.