Neutralization of SARS-CoV-2 by mAbs.

(A) IC50, IC80, and R squared values for neutralization of pseudo-typed GFP-reporter viral particles. Color code is given below. (B) Inhibition of authentic SARS-CoV-2 infection by the 22 mAbs. Virus infected Vero E6 cells were identified by using anti-nucleocapsid antibody (GeneTex GTX135357) conjugated to AF594 after cell fixation and permeabilization. Infected cells were quantified using Image J. (C) Representative images of cells infected with authentic SARS-CoV-2 in the presence of mAbs. mGO53 is shown as a human isotype mAb control [42]. (D) Cell death induction by SARS-CoV-2 infection. Confluent Vero E6 cells were infected with SARS-CoV-2 at MOI:1 in the presence of mAbs in three concentrations as indicated. Viability of cells in five fields of view was monitored with propidium iodide every 6 h for 60 h using an Incucyte S3. (E) Syncytia formation inhibition as measured by the percentage of fusion area between HEK-293 target cells stably expressing hACE2 and HEK-293T cells transiently expressing SARS-CoV-2-Spike (MN908947.3) in the presence of 10 μg/mL of the appropriate antibody. The cells were incubated for 2 h, prior to imaging by the IncuCyte ZOOM system (Essen BioScience) at hourly intervals over 12 h. The percentage area of syncytia was calculated by subtracting the single cell area from the total field area using the following equation: . (F) AUC quantification of (E). (G) Confocal microscopy image of HEK-293T cells transiently expressing SARS-CoV-2-Spike (MN908947.3) and stained with TAU-2212, followed by incubation with FITC-conjugated anti-human secondary antibody. mGO53 serves as an isotype control [42].