Human neutralizing antibodies elicited by SARS-CoV-2 infection

Abstract

The emerging coronavirus SARS-CoV-2 pandemic presents a global health emergency in urgent need of interventions^1–3. SARS-CoV-2 entry into the target cells depends on binding between the receptor-binding domain (RBD) of the viral Spike protein and the ACE2 cell receptor^2,4–6. Here, we report the isolation and characterization of 206 RBD-specific monoclonal antibodies derived from single B cells of eight SARS-CoV-2 infected individuals. We identified antibodies with potent anti-SARS-CoV-2 neutralization activity that correlates with their competitive capacity with ACE2 for RBD binding. Surprisingly, neither the anti-SARS-CoV-2 antibodies nor the infected plasma cross-reacted with SARS-CoV or MERS-CoV RBDs, although substantial plasma cross-reactivity to their trimeric Spike proteins was found. Crystal structure analysis of RBD-bound antibody revealed steric hindrance that inhibits viral engagement with ACE2 and thereby blocks viral entry. These findings suggest that anti-RBD antibodies are viral species-specific inhibitors. The antibodies identified here may be candidates for the development of SARS-CoV-2 clinical interventions.