Fig. 6: Induction of anti-VACV neutralizing and protective antibodies in rhesus macaques.

a Rhesus macaque (n = 3 per group) received a total of 30 µg of a mixture of the three monovalent VLPs or 0.5 ml of Jynneos vaccine subcutaneously at 3-week intervals. BALB/c mice were injected IP with pooled serum obtained after the third immunization either (1) one day before or (2) one day after IN challenge with WRvFire. b Anti-VACV neutralizing titers were determined in duplicate for serum of individual macaques obtained prior to immunizations (Preimmune) or 3 weeks after each immunization. Bars indicate geometric means. Significance between preimmune and immune sera was determined by Kruskal–Wallis/Dunn’s multiple comparison test. c BALB/c mice (n = 5 per group) were injected IP with 0.5 ml of pooled preimmune serum or serum pooled from animals following boost 3 with Jynneos or VLPs. Weight loss and survival were determined following the IN challenge of BALB/c mice with 10⁵ PFU of WRvFire as in scheme (1) of (a). Bars represent SD. d BLI of BALB/c mice that were passively immunized one day before challenge, as in (c). †, death. e Total photon flux from same mice imaged in (d). Regions of interest were drawn to distinguish luminescence emanating from the head or from the body (chest and abdomen). Total photon flux is plotted as photon/s/cm²/sr. Significance between the preimmune and immune values was determined on day 7 by Kruskal–Wallis/Dunn’s multiple comparison test. f Like (c) except that serum was injected one day after mice were challenged with WRvFire as depicted in scheme (2) of (a). g Like (d) except that mice from (f) that received serum one day after infection were imaged. h Like (e) except that photon flux was determined in mice from (g). Source data is provided as a Source Data file. Created in BioRender (2025) https://BioRender.com/sv7gwy2.