Figure 1.

Plasma ELISAs and neutralizing activity. (a) Graph shows area under the curve (AUC) for plasma IgG antibody binding to SARS-CoV-2 Wuhan-Hu-1 RBD 1.5 mo (m) and 6 mo after vaccination for n = 18 samples. Lines connect longitudinal samples. (b) Graph shows AUC for plasma IgG binding to RBD in convalescent infected individuals 1.3 mo after infection (blue; Robbiani et al., 2020) and mRNA vaccinees (gray) after prime (3 wk after first vaccination) or 1.3 mo after second vaccination (Vax2; Cho et al., 2021) compared with Ad26.COV2.S vaccinees 1.5 mo after vaccination (left) or convalescent infected individuals 6.2 mo after infection (Gaebler et al., 2021) and mRNA vaccinees 5 mo after Vax2 (Cho et al., 2021) compared with Ad26.COV2.S vaccinees at 6 mo after vaccination (right). (c) Graph shows anti–SARS-CoV-2 NT₅₀ values of plasma measured by a SARS-CoV-2 pseudotype virus neutralization assay in 293TAce2 cells (Robbiani et al., 2020; Schmidt et al., 2020) using WT (Wuhan Hu-1; Wu et al., 2020) SARS-CoV-2 pseudovirus (Robbiani et al., 2020; Schmidt et al., 2020) in plasma samples shown in panel a. (d) NT₅₀ values of plasma measured by pseudotype virus neutralization assay comparing Ad26.COV2.S vaccinees to convalescent infected individuals (Gaebler et al., 2021; Robbiani et al., 2020) and mRNA vaccinees (Cho et al., 2021) either 1.5 mo (left) or 6 mo (right) after exposure, similar to plasma samples show in panel b. (e) Plasma neutralizing activity against indicated SARS-CoV-2 variants of interest/concern for n = 15 randomly selected samples assayed in HT1080Ace2 cl.14 cells. Wuhan-Hu-1 and Omicron BA.1 NT₅₀ values are derived from Schmidt et al. (2022). See Materials and methods for a list of all substitutions/deletions/insertions in the spike variants. 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. A corresponding WT control containing the R683G substitution was used in panel e. All experiments were performed at least in duplicate and repeated twice. Red bars and values represent geometric mean values. Statistical significance was determined by Wilcoxon matched-pairs signed rank test (a and c), two-tailed Kruskal–Wallis test with subsequent Dunn’s multiple comparisons (b and d), or Friedman test with subsequent Dunn’s multiple comparisons (e).