Phenotypical and Functional Characterization of Unswitched Memory B cells verses Switched during SARS-CoV-2 Infection

Abstract Memory B cells are comprised of unswitched (CD27+IgD+) and switched (CD27+IgD-) subsets. The origin function human memory remains controversial, whereas primed to respond recurrent infection. Unswitched were described be reduced in frequency with severe SARS-CoV2 infection here we report on their activation status, BCR functionality, contribution virally-induced cytokine production. Analyses whole blood from healthy individuals, people immunized against SARS-CoV2, those mild or infection, confirm a loss during demonstrate this is associated increased levels systemic TNFα. We further an ‘IgD+’ only that correlate increase IgG autoantibody (anti-chromatin, anti-cardiolipin, anti-smith) displayed evidence heightened concomitant reduction expression the inhibitory receptor CD72. Functionally, both populations SARS-COV2 harbored signaling competent enhanced activity population. Finally, secrete pro-inflammatory cytokines IL-6 Importantly, major producer TNFα response viral TLR ligands. Together these data suggest contribute inflammatory milieu Supported by grants NIH R01 AI124474 (RP) AI136534 (RMT).