Neutralizing breadth. (a) Heatmaps show IC₅₀ values of antibodies shown in Fig. 5 a against indicated mutant SARS-CoV-2 pseudoviruses listed across the top. Heatmap ranging from 0.1 to 1,000 ng/ml in white to red. Antibody classes listed to the right were determined by competition BLI (see Fig. 4). (b) Ring plots showing fraction of mAbs shown in Fig. 5 a determined to be potently neutralizing (IC₅₀ 1–100 ng/ml, white), poorly neutralizing (IC₅₀ 100–1,000 ng/ml, gray), or nonneutralizing (IC₅₀ > 1,000 ng/ml, black). Mutant or variant SARS-CoV-2 pseudovirus tested is indicated across the top and time point to the left. The number inside the circle indicated the number of antibodies tested. (c) Heatmap of antibodies shown in Fig. 5 b, showing IC₅₀ values of antibodies detected 1.5 mo (left, n = 35) or 6 mo (right, n = 36) after vaccination against indicated variant SARS-CoV-2 pseudovirus listed across the top. Heatmap ranging from 0.1 to 1,000 ng/ml in white to red. The E484K, K417N/E484K/N501Y, and L452R/T478K substitutions, as well as the deletions/substitutions corresponding to viral variants, were incorporated into a spike protein that also includes the R683G substitution, which disrupts the furin cleavage site and increases particle infectivity. Neutralizing activities against mutant pseudoviruses were compared with a WT SARS-CoV-2 spike sequence (NC_045512), carrying R683G where appropriate. All experiments were performed at least in duplicate and repeated twice.