Fig 2.

Adjuvanted pre-fusion stabilized (S-2P) spike protein elicits neutralizing antibody responses after a single dose. Mice were immunized with a single dose of spike trimer protein alone or formulated in CAF01, aluminium hydroxide (AH) or squalene emulsion (SE). Kinetics of IgG antibody responses against spike protein (a) and the receptor binding domain (RBD) (b) were measured by ELISA. c) Neutralization of SARS-CoV-2 by pseudovirus neutralization assay measured at day 7 (upper panels) and 45 (lower panels). d) Correlation between IgG titers against RBD and neutralization titers (Spearman R and p-value indicated) (right panel). Bars show geometric mean ± 95% CI. Statistically significant differences are indicated by * and ** (Kruskal Wallis test, using the unadjuvanted spike trimer group as reference and significance levels of p < 0.05 and p < 0.01, respectively). Figures represent three to six mice per group from one experiment.