Figure 5.

Challenge assay in IFNα/β/γR^−/− mice. (A) Percentage survival. A total of 12 female 8-12-week-old IFNα/β/γR^−/− mice in 3 groups of single, booster, and negative control were immunized with conventional mRNA construct. After 4 weeks p.i., each mouse received 100LD₅₀ of the Ank-2 strain of CCHFV at a final volume of 300 µL and was monitored daily for the onset of clinical symptoms. The protection rate was 100% for mice in the booster dose group in the challenge assay whereas the protection rate was 50% in the single dose group. (B) Percentage of initial body weight. Percentage change in body weight was used as an indicator of the challenged mice’s health condition. The mice in the booster dose group had a clearly faster recovery rate than the mice in the single dose group. The mice in the booster dose group also gained more weight than the single group by the end of the experiment on day 25 post-challenge. Regarding the positive control, the mice in the virus group died on days 3, 5, 7, and 9 post-challenge. All the data are presented as mean±sd. Error bars indicate standard deviation (SD).