National Health Commission Key Laboratory of Systems Biology of Pathogens and Christophe Mérieux Laboratory, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China; Key Laboratory of Respiratory Disease Pathogenomics, Chinese Academy of Medical Sciences, Beijing, China.
National Health Commission Key Laboratory of Systems Biology of Pathogens and Christophe Mérieux Laboratory, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China; Key Laboratory of Respiratory Disease Pathogenomics, Chinese Academy of Medical Sciences, Beijing, China; Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, China.
Lancet Microbe. 2022 May;3(5):e348-e356. doi: 10.1016/S2666-5247(22)00036-2. Epub 2022 Mar 23.
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 SARS-CoV-2 viral proteins tested. There was no difference in the magnitude of T-cell responses or cytokine profiles in individuals with different symptom severity. Moreover, we evaluated both antibody and T-cell responses to the D614G, beta, and delta viral strains. The degree of reduced in-vitro neutralising antibody responses to the D614G and delta variants, but not to the beta variant, was associated with the neutralising antibody titres after SARS-CoV-2 infection. We also found poor neutralising antibody responses to the beta variant; 83 (72·2%) of 115 patients showed no response at all. Moreover, the neutralising antibody titre reduction of the recovered patient plasma against the delta variant was similar to that of the D614G variant and lower than that of the beta variant. By contrast, T-cell responses were cross-reactive to the beta variant in most individuals. Importantly, T-cell responses could be detected in all individuals who had lost the neutralising antibody response to SARS-CoV-2 12 months after the initial infection.
SARS-CoV-2-specific neutralising antibody and T-cell responses were retained 12 months after initial infection. Neutralising antibodies to the D614G, beta, and delta viral strains were reduced compared with those for the original strain, and were diminished in general. Memory T-cell responses to the original strain were not disrupted by new variants. This study suggests that cross-reactive SARS-CoV-2-specific T-cell responses could be particularly important in the protection against severe disease caused by variants of concern whereas neutralising antibody responses seem to reduce over time.
Chinese Academy of Medical Sciences, National Natural Science Foundation, and UK Medical Research Council.
记忆免疫反应对于预防再次感染或降低疾病严重程度至关重要。然而，在初次感染后 12 个月，SARS-CoV-2 的体液和 T 细胞反应的稳健性和功能性仍不清楚。本研究旨在调查恢复期患者在初次感染后 12 个月对原始 SARS-CoV-2 株及其变体的体液和 T 细胞反应的持久性和功能性。
在这项纵向队列研究中，我们招募了 2020 年 1 月 7 日至 5 月 29 日期间从中国医学科学院武汉传染病诊断与治疗研究中心出院的 COVID-19 康复患者。患者于 2020 年 12 月 16 日至 2021 年 1 月 27 日期间进行了随访。我们使用 ELISA 检测了初次感染后 12 个月时 SARS-CoV-2 核衣壳蛋白、Spike 蛋白和受体结合域的 IgM、IgA 和 IgG 抗体的存在情况。在一组血浆样本中，我们使用微量中和测定法分析了对原始 SARS-CoV-2 株以及 D614G、β（B.1.351）和δ（B.1.617.2）变体的中和抗体。我们使用干扰素 γ（IFNγ）酶联免疫吸附斑点（ELISpot）测定法和细胞内细胞因子染色（ICS）测定法分析了 SARS-CoV-2 特异性记忆 T 细胞反应的幅度和广度。抗体反应和 T 细胞反应（即 IFN-γ、白细胞介素 2 [IL-2]和肿瘤坏死因子 α [TNFα]）按年龄和疾病严重程度进行了分析。抗体滴度也根据后遗症症状进行了分析。
我们共纳入了 1096 名患者，包括 289 名（26.4%）初始疾病中度患者、734 名（67.0%）严重初始疾病患者和 73 名（6.7%）危重初始疾病患者。在随访期间，从 141 名患者中采集了配对的血浆样本，用于微量中和测定。在 12 个月的随访中，从 92 名 141 名个体中采集了 PBMCs，其中 80 名通过 ELISpot 进行了分析，92 名通过 ICS 测定法进行了分析，以检测 SARS-CoV-2 特异性记忆 T 细胞反应。在大多数个体中，初次感染后 12 个月可检测到 N-IgG（899 [82.0%]）、S-IgG（1043 [95.2%]）、RBD-IgG（1032 [94.2%]）和中和抗体（115 [81.6%] of 141）。在大多数年龄小于 60 岁的个体中，初次感染后 6 个月和 12 个月时，中和抗体仍保持稳定。对所有测试的 SARS-CoV-2 病毒蛋白均检测到多功能 T 细胞反应。在不同症状严重程度的个体中，T 细胞反应的幅度或细胞因子谱没有差异。此外，我们还评估了 D614G、β和δ病毒株的抗体和 T 细胞反应。与 SARS-CoV-2 感染后中和抗体滴度相关的是，D614G 和 delta 变异株的体外中和抗体反应程度降低，而 beta 变异株则没有。我们还发现对 beta 变异株的中和抗体反应不佳，115 名患者中有 83 名（72.2%）完全没有反应。此外，恢复期患者血浆对 delta 变异株的中和抗体滴度降低与 D614G 变异株相似，低于 beta 变异株。相比之下，在大多数个体中，T 细胞反应对 beta 变异株呈交叉反应。重要的是，在初次感染后 12 个月，所有中和抗体反应丧失的个体中均可检测到 T 细胞反应。
初次感染后 12 个月，SARS-CoV-2 特异性中和抗体和 T 细胞反应仍然存在。与原始株相比，D614G、β和δ病毒株的中和抗体滴度降低，总体上减弱。对原始株的记忆 T 细胞反应未被新变异株破坏。本研究表明，对关注变异株的 SARS-CoV-2 具有交叉反应性的特异性 T 细胞反应可能对预防由变异株引起的严重疾病特别重要，而中和抗体反应似乎会随时间而减少。
中国医学科学院、国家自然科学基金和英国医学研究理事会。
