Fig. 2: Neutralizing antibody titers and hACE2 receptor inhibition activity of COVID-19 patients’ plasma during hospitalization.

SARS-CoV-2 neutralizing antibody titers (PsVNA50) in plasma at various time-points as determined by pseudovirion neutralization titer 50 (PsVNA50) in Vero E6 cells are shown in colored curves, and the percentage of ACE2 inhibition values at different days post-onset of symptoms are shown in black curves. a “Expired” patients (n = 8); b “ICU-survived” patients (n = 11); and c “non-ICU survived” (n = 6) patients. Expired patients (patient number’s starting with e); ICU-survived patients (patient number’s starting with IS); and non-ICU survived patients (patient number’s starting with NS). Virus neutralization PsVNA50s titers were calculated with GraphPad prism version 8. Percent inhibition of hACE2 binding to RBD in presence of 1:100 dilution of COVID-19 plasma was measured by ELISA. The neutralization and ACE2-inhibition experiments were performed twice independently with similar results. d Area under the curve (AUC) was determined for the PsVNA50 or the percent ACE2 inhibition from day 1 through day 20 of the three COVID-19 patient groups to control for the window of samples collected. Bar chart shows datapoints for each individual and presented as mean values ± SEM. The statistical significances between the groups were determined by non-parametric (Kruskal–Wallis) statistical test using Dunn’s multiple comparisons analysis in GraphPad prism for the area under curve (AUC values) between “expired” patients (red; n = 8 biologically independent individuals), “ICU-survived” patients (blue; n = 11 biologically independent individuals), and “non-ICU survived” patients (green; n = 6 biologically independent individuals) did not identify any statistical significance (p > 0.05).