Fig. 3.

Prevention of SARS-CoV infection in aged mice. The indicated amount of equine anti-SARS-CoV F(ab')₂ fragments was injected i.p. into aged mice on day-1 and the animals were challenged with 1 × 10⁴ TCID₅₀ of SARS-CoV i.n. on day 0. Virus titres and copies in lung homogenates were measured on day 2 p.i., and shown as mean values, calculated from four mice per group. Error bars indicate standard errors. Panel A: CPE assays of virus titres in aged mice lungs. Virus titres are expressed as log₁₀TCID₅₀/g lung tissue. The lower limit of detection of virus in a 10% w/v suspension of lung homogenate is 1.5 log₁₀TCID₅₀ per gram (dotted line). Panel B: qRT-PCR assays of virus copies in experimental animal lungs. Copies of N gene derived from SARS-CoV were expressed as absolute copies of N gene/g of lung tissue. The antibody-negative control mice received the indicated amount of non-immune equine antibody. ^⁎p < 0.01 (1-way ANOVA assay) compared with 4 mg/kg of non-immune equine antibody control.