Fig. 2: Systemic immune response and protection efficacy of rNA-N1-MPP vaccine adjuvanted with BDX100 or BDX301 adjuvants in BALB/c mice.

a B- and follicular T-helper (Tfh) cell subpopulation percentages (activated B-cells: CD3^‒CD19⁺CD38⁺GL7^‒ CD273^‒CD80⁺, memory B-cells: CD3^‒CD19⁺CD38⁺GL7^‒CD273⁺CD80⁺, Tfh: CD3⁺CD4⁺ CD185⁺PD1⁺) in the spleens of vaccinated mice 10 days post boost (n = 5). b Total IgG response against the recombinant neuraminidase protein from the homologous influenza virus strain A/Michigan/45/2015 H1N1 measured with ELISA. Dots represent individual areas under the curves (AUC) values (n = 8). c IgG1/IgG2a ratio at 0.3 OD490. Dots represent individual values (n = 8). d–f Neuraminidase inhibition activity of sera from the vaccinated mice against various influenza virus strains (A/Michigan/45/2015 H1N1 (d), A/Singapore/GP1908/2015 H1N1 (e), A/Netherlands/602/2009 (H1N1)pdm09 (f). Dots represent individual ID₅₀ values for each sample (n = 5). Bars represent average values. g Total IgG response against the recombinant neuraminidase proteins from various heterologous influenza virus strains (A/Puerto Rico/8/1934 H1N1, A/New Caledonia/20/1999 H1N1, A/Wisconsin/67/2022 H1N1, A/Vietnam/1203/2004 H5N1, A/bald eagle/FL/W22-134-OP/2022 H5N1, A/dairy cattle/Texas/24-008749-001-original/2024 H5N1. Dots represent individual AUC values; bars represent average values (n = 8). h, i Survival and body weight dynamics after the challenge with 5 × LD₅₀ (9 × 10² PFU/mouse) of A/Singapore/GP1908/2015 H1N1 (n = 10). j Viral titers in lungs on day 5 after the challenge with 0.5 × LD₅₀ (90 PFU/mouse) of A/Singapore/GP1908/2015 H1N1 (n = 5) a–g, j Groups were compared using ANOVA followed by the Tukey posthoc test. P-values for the groups with statistically significant differences are shown on the plots.