Fig. 2.
The effect of Nsp3-S676T on viral replication and pathogenesis in mice. BALB/c mice were infected with 5,000 PFU of rMA30 or rMA30Nsp3-S676T. (A) At 2 and 4 dpi, lungs were harvested to evaluate viral titers, levels of subgenomic RNA (sgRNA, N gene) and genomic RNA [gRNA, ORF1 (nsp12)]. LOD: limit of detection. rMA30 (n = 6); rMA30Nsp3-S676T (n = 7). For statistical analysis, in samples with undetectable amounts of virus, we assigned a value of 10 PFU/mL. (B) Gross lung pathology and (C) histopathological analysis of the lungs, harvested at 4 dpi. (n = 3 mice/group). (Scale bars, 430 [Upper] and 86 [Lower] µm, respectively.) (D) Lung edema was quantified as described in Materials and Methods (n = 3 each group). Asterisks indicate pulmonary edema. P values were calculated by a two-tailed, unpaired t test with Welch’s correction. (A) Data are combined from two independent experiments.