Fig. 2: Attenuation of Nsp1-K164A/H165A in the respiratory tract of K18-hACE2 mice.

a Overall design of the study. b–d Weight loss (b), survival (c), and clinical scores (d) were recorded in infected mice for up to 8 days following infection. Data in b–d reflect n = 10 mice/group from one experiment. e, f infectious viral titers of nasal turbinates at 2 dpi (e) or 4 dpi (f) were determined by plaque-forming assays. Each solid circle represents one animal. **p = 0.0229, one-way ANOVA. ns, non-significant. g–i infectious viral titers of lung homogenates at 2 dpi (g), 4 dpi (h), and 6 dpi (i). Median log₁₀-transformed infectious titers at 2 dpi are 6.3 (IQR, 5.2 to 6.7), 5.4 (IQR, 2.2 to 5.8), 4.3 (IQR, 3.3 to 4.8), and 4.7 (IQR, 2.4 to 5.8) for WA1/2020, ΔPRRA, Nsp1-K164A/H165A, and Nsp1-N128S/K129E, respectively. Median log₁₀-transformed infectious titers at 6 dpi are 5.4 (IQR, 5.0 to 5.5), 5.4 (IQR, 4.7 to 5.5), 3.9 (IQR, 3.3 to 4.2), and 4.5 (IQR, 2.5 to 5.2) for WA1/2020, ΔPRRA, Nsp1-K164A/H165A, and Nsp1-N128S/K129E, respectively. *p < 0.05, ***p < 0.001. j Log₁₀-transformed sgRNA titers (E gene) were quantified by RT-qPCR. *p < 0.05. k–m Infectious viral titers of brain homogenates at 2 dpi (k), 4 dpi (i), and 6 dpi (m). *p < 0.05, **p < 0.01. Data in e–m reflect n = 5 WA1/2020, n = 6 ΔPRRA, n = 6 Nsp1-K164A/H165A, n = 6 Nsp1-N128S/K129E, or n = 2 uninfected mice/group from one experiment. Statistical analyses were done by one-way ANOVA in this figure. Error bars indicate standard deviation. n–w H&E stained lungs from uninfected (n, o), WA1/2020 (p, q), ΔPRRA (r, s), Nsp1-K164A/H165A (t, u), Nsp1-N128S/K129E (v, w). Red dotted lines denote areas of impact (consolidated). (o), (q), (s), (u), and (w) are closeup images of (n), (p), (r), (t), and (v), respectively. Experiments were conducted once, with multiple biological replicates. Source data are provided as a Source data file. Scale bar in (n), (p), (r), (t), and (v), 500 μm; in (o), (q), (s), (u), and (w), 90 μm.