Fig. 10: JAK1 degradation mediated by AIV PB2 significantly increases the virulence of AIV in mice.

a, b The mice (n = 10 per group) were intranasally inoculated (10⁶ EID₅₀ per mouse) with rJY, rJYM, rCZ, or rCZM virus and monitored for 14 d for body weight loss (a) and survival (b). c Gloss lesions of lungs from the infected mice on 2 and 5 dpi. Severe pneumonia with diffuse consolidation was outlined in yellow. The images are from representative one of five mice. d Viral titers in the lungs (n = 5 per group) were determined on 2 and 5 dpi by plaque assay. e–h Hematoxylin/eosin (HE) staining (e) and scoring (f), immunohistochemistry (IHC) staining (g), and scoring of lung sections (h). Scale bar, 200 μm. The images are from representative one of five mice. The scores were calculated from five mice. i Immunoblots of lung tissue from the infected mice. j Quantification of JAK1 expression on the immunoblots (i) and normalized with actin (n  =  3). k, l qPCR analysis of ISG15 (k) and IFIT1 (l) mRNA in lung from the infected mice on 2 dpi (n = 3). dpi, days post-infection. Data are presented as the mean ± SD. Statistical significance was determined by unpaired two-tailed Student’s t test in a, d, f, h, j–l or log-rank test in b.