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

Abstract SARS-CoV-2 is a respiratory pathogen that can cause severe disease in at-risk populations but results asymptomatic infections or mild course of the majority cases. We report identification SARS-CoV-2–reactive B cells human tonsillar tissue obtained from children who were negative for coronavirus 2019 prior to pandemic and generation mAbs recognizing Spike protein these cells. These Abs showed reduced binding proteins variants did not recognize endemic coronaviruses, subsets reacted with commensal microbiota exhibited SARS-CoV-2–neutralizing potential. Our study demonstrates pre-existing various cell upper tract lymphoid may lead rapid engagement contribute prevent manifestations symptomatic disease.