Fig. 7. Virological characteristics of recombinant viruses bearing the single mutations in S and ORF8 in vivo.
Syrian hamsters were intranasally inoculated with the recombinant viruses rXBB.1, rXBB.1/S:S486P, rXBB.1/ORF8:G8stop, and rXBB.1.5. Six hamsters of the same age were intranasally inoculated with saline (uninfected). Six hamsters per group were used to routinely measure the body weight (A). Four hamsters per group were euthanized at 2 and 5 d.p.i. and used for virological and pathological analysis (B–E). A Body weight of infected hamsters (n = 6 per infection group). B Viral RNA loads in the oral swab (n = 4 per infection group). C Percentage of the viral N-positive cells in the lungs at 2 and 5 d.p.i. of infected hamsters. Representative figures (N-positive cells are shown in brown) are shown in (D). Uninfected lung alveolar space and bronchioles are also shown. E H&E staining of the lungs of infected hamsters. Representative images showing the same area with the viral N staining as in (D). F Histopathological scoring of lung lesions (n = 4 per infection group). Representative pathological features are reported in our previous studies1–4,21–24. (A–C, and F) Data are presented as the average ± SEM.