Figure 5.

Serum neutralization against several newly emerged Omicron variants. (A) Pseudovirus-dependent in vitro neutralization assays against wildtype SARS-CoV-2, Delta, Omicron (B.1.1.529), BA.2.75, BA.4, BF.7, BQ.1.1, XBB pseudoviruses in the presence of different serum dilutions of the selected top 11 neutralizers. The highest serum concentration (x-axis) was 2.5% with a 1:2 serial dilution for eight dilutions in total. The neutralization data were analyzed based on the relative luciferase activity (y-axis) using Prism software by nonlinear regression (curve fit) method. (B) A heat map for serum NT₅₀ values of the selected top 11 neutralizers. Each row represents a serum sample, while each column represents neutralization assays against an indicated SARS-CoV-2 variant. Based on the performed pseudovirus-dependent in vitro neutralization assays in (A), the serum neutralization titer NT₅₀ value for each serum sample against a certain SARS-CoV-2 variant was calculated using Prism software. Higher NT₅₀ value means more potent serum neutralizing activity. The serum exhibiting no neutralization activity has NT₅₀ lower than 100. (C) Comparison of the calculated NT₅₀ values between wildtype SARS-CoV-2 and the other different variants. The p-values were calculated using the Friedman test and Dunn’s multiple comparisons test, and no significant difference (n.s.) among the NT₅₀ values for wildtype SARS-CoV-2, and Delta and Omicron variants was observed.