Department of Immunology, University of Toronto, Toronto, Ontario, Canada.
Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
J Immunol. 2021 Nov 15;207(10):2581-2588. doi: 10.4049/jimmunol.2100606. Epub 2021 Oct 4.
SARS-CoV-2 is a respiratory pathogen that can cause severe disease in at-risk populations but results in asymptomatic infections or a mild course of disease in the majority of cases. We report the identification of SARS-CoV-2-reactive B cells in human tonsillar tissue obtained from children who were negative for coronavirus disease 2019 prior to the pandemic and the generation of mAbs recognizing the SARS-CoV-2 Spike protein from these B cells. These Abs showed reduced binding to Spike proteins of SARS-CoV-2 variants and did not recognize Spike proteins of endemic coronaviruses, but subsets reacted with commensal microbiota and exhibited SARS-CoV-2-neutralizing potential. Our study demonstrates pre-existing SARS-CoV-2-reactive Abs in various B cell populations in the upper respiratory tract lymphoid tissue that may lead to the rapid engagement of the pathogen and contribute to prevent manifestations of symptomatic or severe disease.
SARS-CoV-2 是一种呼吸道病原体，可导致高危人群发生重症疾病，但在大多数情况下可引起无症状感染或轻症疾病。我们报告了在大流行前新型冠状病毒病检测为阴性的儿童的扁桃体组织中鉴定出 SARS-CoV-2 反应性 B 细胞，并从这些 B 细胞中产生了识别 SARS-CoV-2 刺突蛋白的 mAb。这些抗体与 SARS-CoV-2 变体的刺突蛋白结合能力降低，且不识别地方性冠状病毒的刺突蛋白，但亚群与共生微生物群反应，并表现出中和 SARS-CoV-2 的潜力。我们的研究表明，上呼吸道淋巴组织中的各种 B 细胞群体中存在预先存在的 SARS-CoV-2 反应性 Abs，这可能导致病原体的快速结合，并有助于预防有症状或严重疾病的发生。
