PMC

Ventrodorsal thoracic X-rays from IFN-α2b– and ribavirin–treated (RM1–RM3) and untreated (RM4–RM6) rhesus macaques imaged before MERS-CoV infection (day 0) and on day 3 after infection. Areas of interstitial infiltration, indicative of pneumonia, are circled. R indicates the right side of the animal.

(a) Singular value decomposition–coupled multidimensional scaling (SVD-MDS) representation showing the distribution of individual samples following dimensionality reduction. This represents the similarity of the gene expression patterns of the following groups: uninfected, untreated control lung (black), MERS-CoV–infected, untreated lung (red, RM4–RM6) and MERS-CoV–infected, treated lung (blue, RM1–RM3). All lung samples were from the lower right lobe. Group means are shown as open circles, and distances from uninfected, untreated controls for MERS-CoV–infected, treated and MERS-CoV–infected, untreated macaques are shown as arrows between group means. The distance between points and groups is indicative of the differences in gene expression between the different groups. (b) Heatmap showing log₁₀ expression ratios to untreated, MERS-CoV–infected group mean of 205 DEGs associated with IFN-α2b and ribavirin treatment, as determined by Welch's t-test (P < 0.01, fold change ≥ 1.5) and grouped by hierarchical clustering. (c) Molecular interaction network built using DEGs shown in b. Solid lines show direct molecular interactions; dashed lines show indirect molecular interactions. Red molecules are those upregulated in treated animals relative to untreated, whereas turquoise molecules are downregulated.

(a) Schematic showing the experiment schedule. IFN-α2b was delivered subcutaneously at 5 MIU/kg. Ribavirin was delivered as an initial loading dose intravenously at 30 mg/kg (full circle) with subsequent doses delivered intramuscularly at 10 mg/kg (half-full circle). Rhesus macaques were given either IFN-α2b and ribavirin (treated, RM1–RM3, n = 3) or sham treatment (untreated, RM4–RM6, n = 3) on the same schedule. (b) Clinical score (see also ) determined from an established scoring sheet. (c) Changes in oxygen saturation from preinoculation values (% δSPO₂). (d,e) The total number of white blood cells (WBCs) (d) and neutrophils (e) in blood samples obtained from animals 0, 24, 48 and 72 h after infection. All values are mean ± s.d. (two-way analysis of variance (ANOVA), Bonferroni's post hoc test, ^**P < 0.01). A single sample per time point per animal was used for the analysis. K, cell count × 10³.

(a) Gross pathology of lungs from IFN-α2b– and ribavirin–treated (left) and untreated (middle) MERS-CoV–infected rhesus macaques 72 h after inoculation. The percentage area showing gross pathology is indicated on the right. Six lung lobes per animal (dorsal and ventral) from three animals per group were scored. (b) The mean viral load determined by qRT-PCR from individual tissues collected at necropsy. The mean viral load of all lung lobes combined is indicated in the inset. Log TCID₅₀ eq/g, log TCID₅₀ equivalents per gram tissue; one sample per tissue per animal from three animals per group were analyzed. (c,d) Lung tissue collected at necropsy stained with H&E. Pulmonary arterioles appear normal in treated animals (RM2) (c, left). Treated RM2 shows mild acute bronchointerstitial pneumonia demonstrated by multifocal accumulations of inflammatory cells centered on terminal bronchioles (c, middle). Higher magnification of the boxed region showing thickening of the alveolar septae by small numbers of neutrophils, macrophages, fibrin and edema (asterisk) (c, right). Pulmonary arterioles are bounded by moderate numbers of lymphocytes indicative of perivasculitis in untreated animals (d, left). Larger numbers of inflammatory cells and fibrin also extend into alveolar spaces. Untreated RM4 shows marked coalescing bronchointerstitial pneumonia with abundant alveolar fibrin and edema (d, middle). Higher magnification of untreated RM4 showing airways filled with organizing fibrin (arrow) and moderate numbers of viable and degenerate neutrophils and macrophages (d, right). (e) Percentage of neutrophils in lung sections stained with myeloperoxidase. Two sections per lobe and six lobes per animal from three animals per group were analyzed. All values are mean ± s.d. (t-test, ^*P < 0.05, ^**P < 0.01).