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. 2024 Jul 16;15:1429909. doi: 10.3389/fimmu.2024.1429909

Figure 7.

Figure 7

Vaccine induced protection against lethal EBOV infection. (A) Timeline of the EBOV challenge experiment. C57BL/6NHsd mice (n = 15) were vaccinated with BCG, and subsequently primed and boosted with 0.05 μg of the indicated recombinant protein vaccine (WT GP-FL or the Th GP-FL) in alum as indicated in the schematic. MA-EBOV infection (i.p.) with 100 pfu per mouse was performed on day 98, which corresponds to day 0 (blue) of the challenge experiment. Arrows represent blood sample collections, and harvesting of blood, livers, and spleens at the last collection point after sacrifice. (B) Serum samples collected 2 weeks after administering WT GP-FL (WT) or the Th GP-FL (Th) vaccines for both priming and boosting time-points were analyzed by ELISA for anti-EBOV GP IgG1 (red) and IgG2c (blue) antibodies. (C) Endpoint titers of anti-EBOV GP antibodies following boosting with the WT or Th vaccines were also analyzed by ELISA in sera from mice primed and boosted with either PBS or 0.05 μg of the indicated recombinant protein vaccine. (D) Naïve mice (black) or mice that received the WT (red) or Th (blue) vaccines were challenged with MA-EBOV and the times to death (left panel) and body weight changes (right panel) for individual mice were recorded. The Mantel-Cox test was performed for comparison of the survival curves; (****p < 0.0001). (E) Five days after the challenge, mice (n = 5) were sacrificed to determine viral titers from the corresponding organs. The median with interquartile ranges is shown and analyzed using Kruskal-Wallis one way ANOVA nonparametric test with and Dunn’s multiple comparison test; (**p < 0.01, *p < 0.05). (F) The anti-EBOV GP IgG1 and IgG2c antibody titers were also measured from serum of these mice sacrificed at day 5 after challenge (****p < 0.0001, ***p < 0.001, **p < 0.01, *p < 0.05 two-way ANOVA test and Sidak’s multiple comparison test). (G) Twenty-eight days after the challenge, the surviving mice were sacrificed, and blood was collected to measure anti-EBOV GP IgG1 and IgG2c antibody titers.