Asymptomatic and symptomatic SARS-CoV-2 infections elicit polyfunctional antibodies.

Dufloo, J.; Grzelak, L.; Staropoli, I.; Madec, Y.; Tondeur, L.; Anna, F.; Pelleau, S.; Wiedemann, A.; Planchais, C.; Buchrieser, J.; Robinot, R.; Ungeheuer, M.-N.; Mouquet, H.; Charneau, P.; White, M.; Levy, Y.; Hoen, B.; Fontanet, A.; Schwartz, O.; Bruel, T.

A large proportion of SARS-CoV-2 infected individuals remains asymptomatic. Little is known about the extent and quality of their antiviral humoral response. Here, we analyzed antibody functions in 52 asymptomatic infected individuals, 119 mild and 21 hospitalized COVID-19 patients. We measured anti- Spike antibody levels with the S-Flow assay and mapped SARS-CoV-2 Spike- and N-targeted regions by Luminex. Neutralization, complement deposition and Antibody-Dependent Cellular Cytotoxicity (ADCC) were evaluated using replication-competent SARS-CoV-2 or reporter cell systems. We show that COVID-19 sera mediate complement deposition and kill infected cells by ADCC. Sera from asymptomatic individuals neutralize the virus, activate ADCC and trigger complement deposition. Antibody levels and activities are slightly lower in asymptomatic individuals. The different functions of the antibodies are correlated, independently of disease severity. Longitudinal samplings show that antibody functions follow similar kinetics of induction and contraction, with minor variations. Overall, asymptomatic SARS-CoV-2 infection elicits polyfunctional antibodies neutralizing the virus and targeting infected cells. - Sera from convalescent COVID-19 patients activate the complement and kill infected cells by ADCC. - Asymptomatic and symptomatic SARS-CoV-2-infected individuals harbor polyfunctional antibodies. - Antibody levels and functions are slightly lower in asymptomatic individuals - The different antiviral activities of anti-Spike antibodies are correlated regardless of disease severity. - Functions of anti-Spike antibodies have similar kinetics of induction and contraction.