ABSTRACT
Background: Emerging evidence points out to potential benefits from Fc-mediated effector functions in SARS-CoV-2 infection. Some Fc-mediated effector functions such as antibody-dependent cellular cytotoxicity (ADCC) or antibody-dependent cellular phagocytosis (ADCP) require recognition of the antigen at the surface of infected cells. Methods: To evaluate the expression levels of SARS-CoV-2 Spike at the surface of infected airway epithelial cells, we developed an intracellular staining against SARS-CoV-2 nucleocapsid (N). This assay allows the distinction between infected versus uninfected cells. Human primary airway epithelial cells (pAECs) were infected with authentic SARS-CoV-2 D614G or Alpha variants. Infected cells were identified with an anti-N antibody and cell surface expression of Spike measured with the conformational-independent anti-S2 CV3-25 antibody. Results: We found robust SARS-CoV-2 Spike expression at the cell surface of pAECs. Infected cells were readily recognized with plasma from convalescent and vaccinated individuals. Importantly, recognition of SARS-CoV-2 infected cells strongly correlated with Fc-mediated effector functions measured in a cohort of vaccinated naïve and previously-infected individuals. Conclusion: Altogether, our findings further support the importance of measuring Fc-mediated effector function in infection and vaccination settings for SARS-CoV-2.