Fig. 2: Higher level humoral and cellular responses with mRNA vaccination.

a Neutralizing antibody titers are shown across the whole study timeline. Arrows indicate immunizations. Statistical significance was calculated for peak antibody responses (week 6) and at study end (week 50) using Kruskal–Wallis test as per Supplementary Fig. 4a. Connecting lines indicate group means. The dashed line across refers to the RVNA titer of 0.5 IU/mL which is suggested by the WHO as the VNT threshold. n = 18 biologically independent animals. b Total IgG titers expressed as the half-maximal effective concentration (EC₅₀) calculated with a sample dilution series measured by ELISA are shown across the whole study timeline. Arrows indicate immunizations. Connecting lines indicate group means. n = 18 biologically independent animals. Statistical significance was calculated for peak antibody responses (week 6) and at study end (week 50) using Kruskal–Wallis test as per Supplementary Fig. 4b. c Antigen-specific plasmablasts are measured by B cell ELISpot prior to boost (baseline) and four days after the boost. n = 18 biologically independent animals. Statistical differences were assessed at day 4 using Mann–Whitney U test. Error bars indicate mean ± SD. d Longitudinal data of antigen-specific antibody-secreting plasma cells in the bone marrow enumerated by B cell ELISpot at the different study timepoints. n = 18 biologically independent animals. Statistical significance was calculated for peak antibody responses (week 6) and at study end (week 50) using Kruskal–Wallis test. Representative flow cytometry plots (e) and longitudinal data (f) showing the generation and expansion of antigen-specific memory B cells. Data are shown for week-1 (prior to prime immunization), 2 weeks after prime immunization (week 2), 2 weeks after boost (week 6 from study start) and from a later time point (week 18) from which single cells have also been sorted. n = 18 biologically independent animals. Statistical significance was calculated at weeks 2, 6, and 18 using Kruskal–Wallis test. Error bars indicate mean ± SD. Representative flow cytometry plots (g) and longitudinal data (h) showing the generation of antigen-specific Th1 cells identified by their ability to produce intracellular IL-2 and IFN-γ upon stimulation with a pool of overlapping peptides covering the whole RABV-G protein. Data are shown for unstimulated and stimulated cells collected prior to immunization (week 0), 2 weeks after prime (week 2) and 2 weeks after boost (week 6 from study start) immunizations. n = 18 biologically independent animals. Statistical significance was calculated at week 6 using Kruskal–Wallis test. All statistical tests comparing the study groups were two-tailed tests. Error bars indicate mean ± SEM.