SARS-CoV-2-specific antibody and T-cell responses 1 year after infection in people recovered from COVID-19: a longitudinal cohort study

• Published in: The Lancet. Microbe 2022-05, Vol.3 (5), p.e348-e356
• Main Authors: Guo, Li, Wang, Geng, Wang, Yeming, Zhang, Qiao, Ren, Lili, Gu, Xiaoying, Huang, Tingxuan, Zhong, Jingchuan, Wang, Ying, Wang, Xinming, Huang, Lixue, Xu, Liuhui, Wang, Conghui, Chen, Lan, Xiao, Xia, Peng, Yanchun, Knight, Julian C, Dong, Tao, Cao, Bin, Wang, Jianwei
• Format: Article
• Language: English
• Subjects: Antibodies, Neutralizing; Antibodies, Viral; Cohort Studies; COVID-19 - epidemiology; Cytokines; Humans; Immunoglobulin G; Longitudinal Studies; SARS-CoV-2; T-Lymphocytes
• ISSN: 2666-5247; 2666-5247
• DOI: 10.1016/S2666-5247(22)00036-2

The memory immune response is crucial for preventing reinfection or reducing disease severity. However, the robustness and functionality of the humoral and T-cell response to SARS-CoV-2 remains unknown 12 months after initial infection. The aim of this study is to investigate the durability and functionality of the humoral and T-cell response to the original SARS-CoV-2 strain and variants in recovered patients 12 months after infection. In this longitudinal cohort study, we recruited participants who had recovered from COVID-19 and who were discharged from the Wuhan Research Center for Communicable Disease Diagnosis and Treatment at the Chinese Academy of Medical Sciences, Wuhan, China, between Jan 7 and May 29, 2020. Patients received a follow-up visit between Dec 16, 2020, and Jan 27, 2021. We evaluated the presence of IgM, IgA, and IgG antibodies against the SARS-CoV-2 nucleoprotein, Spike protein, and the receptor-binding domain 12 months after initial infection, using ELISA. Neutralising antibodies against the original SARS-CoV-2 strain, and the D614G, beta (B.1.351), and delta (B.1.617.2) variants were analysed using a microneutralisation assay in a subset of plasma samples. We analysed the magnitude and breadth of the SARS-CoV-2-specific memory T-cell responses using the interferon γ (IFNγ) enzyme-linked immune absorbent spot (ELISpot) assay and intracellular cytokine staining (ICS) assay. The antibody response and T-cell response (ie, IFN-γ, interleukin-2 [IL-2], and tumour necrosis factor α [TNFα]) were analysed by age and disease severity. Antibody titres were also analysed according to sequelae symptoms. We enrolled 1096 patients, including 289 (26·4%) patients with moderate initial disease, 734 (67·0%) with severe initial disease, and 73 (6·7%) with critical initial disease. Paired plasma samples were collected from 141 patients during the follow-up visits for the microneutralisation assay. PBMCs were collected from 92 of 141 individuals at the 12-month follow-up visit, of which 80 were analysed by ELISpot and 92 by ICS assay to detect the SARS-CoV-2-specific memory T-cell responses. N-IgG (899 [82·0%]), S-IgG (1043 [95·2%]), RBD-IgG (1032 [94·2%]), and neutralising (115 [81·6%] of 141) antibodies were detectable 12 months after initial infection in most individuals. Neutralising antibodies remained stable 6 and 12 months after initial infection in most individuals younger than 60 years. Multifunctional T-cell responses were detected for all SA