Virulence and viral growth of SARS-CoV-nsp1* mutants <i>in vivo</i>.

<p>BALB/c mice were intranasally infected with 100,000 pfu of wt, and SARS-CoV-nsp1-ΔA, -ΔB, -ΔC and -ΔD viruses (5 mice per group). (A) Animals were monitored daily for weight loss and survival. (B) Viral titers in lungs were determined at 2 and 4 days post infection (3 mice per group and time point). Error bars represent the standard deviations from three independent mice in each case. (C) Lung tissue sections from mice infected with the different recombinant viruses were prepared and stained with hematoxylin and eosin at 2 and 4 dpi. Three independent mice per group were analyzed. Original magnification was 20x and representative images are shown.