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. 2022 Oct 27;31(2):374–386. doi: 10.1016/j.ymthe.2022.10.011

Figure 4.

Figure 4

Protection against lethal EBOV infection induced by two immunizations with GP and NP or GP + NP

C57BL/6J IFNAR−/− mice (six per group) were injected with LNP-saRNA vaccine candidates on days 0 and 35. The vaccine contained 5 μg GP saRNA plus 2.5 μg saRNA encoding the replicase only (GP + filler), 2.5 μg NP saRNA plus 5 μg saRNA encoding the replicase only (NP + filler), or both (GP + NP). LNP filler contained only the replicase encoding saRNA without insertion of a gene of interest. Serum samples were collected before immunization (day 0), and after prime (days 21 and 35) and boost immunization (day 50). Mice were infected i.p. with 1,000 PFU of EBOV on day 56, and survival was recorded for 14 days (six mice per group, except NP group where only five mice were infected). (A) Schematical overview of the experimental setting. (B) Seroconversion per group over time. ELISA for EBOV GP and EBOV NP was performed of serum samples (1:100 dilution) from the indicated days, as described in Figure 2 (four or five mice per group). (C) Concentration of GP- and NP-specific IgG on day 50, determined by ELISA as described in Figure 2 (four or five mice per group). (D) Neutralizing antibody titers against authentic EBOV on day 50. The dotted line indicates the lower limit of detection (LLOD) (six mice per group). (E) Body weight curves for the different groups after EBOV infection. (F) Clinical scores of the different groups. Mice that developed severe clinical signs of infection and/or exceeded 15% of body weight loss were euthanized. (G) Survival over time. (H) Infectious EBOV particles were quantified by plaque titration in serum samples from days 5 and 14 after infection or at the day of the sacrifice. (I) EBOV genome copies in liver and spleen samples of the mice obtained at day 14 post infection or at the day of the sacrifice, by EBOV GP-specific qRT-PCR. Symbols indicate individual mouse values, with group mean values indicated by horizontal lines for all graphs, except for (E–G), where symbols represent group average values (six or five [NP] mice per group). Asterisks indicate statistical significance as detailed by bars between relevant groups: ∗p ≤ 0.05; ∗∗p ≤ 0.01; ∗∗∗∗p < 0.0001.