SARS-CoV-2-Reactive Mucosal B Cells in the Upper Respiratory Tract of Uninfected Individuals

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoids / immunology*
  • Antibodies, Viral / metabolism
  • B-Lymphocyte Subsets / immunology*
  • B-Lymphocytes / immunology*
  • COVID-19 / immunology*
  • Child
  • HEK293 Cells
  • Humans
  • Immunologic Memory
  • Lymphocyte Activation
  • Mucous Membrane / immunology*
  • Receptors, Antigen, B-Cell / genetics*
  • Respiratory System / immunology*
  • SARS-CoV-2 / physiology*
  • Single-Cell Analysis
  • Spike Glycoprotein, Coronavirus / immunology
  • Transcriptome


  • Antibodies, Viral
  • Receptors, Antigen, B-Cell
  • Spike Glycoprotein, Coronavirus
  • spike protein, SARS-CoV-2