Fig. 2: Immunogenicity of VLA2001 in cynomolgus macaques.

a Study design. b Geometric mean titer (AU/mL; error bars represent the 95% confidence interval) of IgG binding to SARS-CoV-2 S, RBD and N proteins measured in sera samples (n = 8 biologically independent animals per group). BL: baseline approximatively 3 weeks before first immunization. Dotted vertical lines represent vaccinations. c Individual neutralizing titers to SARS-CoV-2 (NT₅₀: 50% neutralizing titer; Box and whiskers, min to max) (non-parametric Kruskal-Wallis and Dunn’s multiple comparisons tests; n = 8 biologically independent animals per group) in sera sampled 5 weeks following first immunization. Lower limit of quantification was 5. Dotted horizontal line indicates the titer of the WHO International Standard for anti-SARS-CoV-2 immunoglobulin in human determined in the same assay. Graph starts at 4.6; Individual values (% of inhibition) of antibodies blocking the binding of SARS-CoV-2 S protein to ACE2 using WA1, B.1.1.7, B.1.351, B.617.2 + AY.4 alt seq 2, B.1.1.529 + BA1, BA.2, BA.2.12.1, BA.2.75 and BA.5 antigens in sera sampled at week 7 post first immunization. Horizontal bars represent the geometric means (non-parametric Kruskal-Wallis and Dunn’s multiple comparisons tests; n = 8 biologically independent animals per group). d Individual number of IFN-γ-secreting cells analyzed by ELISpot after ex vivo overnight stimulation with SARS-CoV-2 S1, S2, RBD or N overlapping peptide pools and plotted as spot-forming cells (SFC) per 1 × 10⁶ PBMCs, at week 5 post first immunization. Horizontal bars represent the geometric means (non-parametric Kruskal-Wallis and Dunn’s multiple comparisons tests; n = 8 biologically independent animals per group). e Frequency of antigen-specific Th1 CD4⁺ T cells (CD154⁺ and IFN-γ⁺ +/- IL-2⁺ +/- TNF-α⁺) in the total CD4⁺ T cell population at week 5 post first immunization. PBMCs were stimulated overnight with the SARS-CoV-2 S1, S2, RBD or N overlapping peptide pools. Horizontal bars represent the geometric means (non-parametric Kruskal-Wallis and Dunn’s multiple comparisons tests; n = 8 biologically independent animals per group). f Polyfunctionality of antigen-specific CD4⁺ T cells (CD154⁺ or TNF-α⁺ or IL-2⁺ or IFN-γ⁺ and IL-2⁺/TNF-α⁺ or IFN-γ⁺/TNF-α⁺ or IFN-γ⁺/IL-2⁺ and IFN-γ⁺/IL-2⁺/TNF-α⁺) in the total CD4⁺ T cell population at week 5 post first immunization. PBMCs were stimulated overnight with SARS-CoV-2 S1, S2, RBD or N overlapping peptide pools. Each intersection on the radar charts is separated by 0.025. In (b), Control group is represented by black circle, High dose group is represented by blue square and Medium dose group is represented by orange triangle. In panels c to e, each animal is identified by distinct symbols (Supplementary Table 1 for matching symbols). In (c–f), Control group is in black, High dose group is in blue and Medium dose group is in orange.