Table 1.
Clinic, pathology and diagnosis.
Figure 1.
Radiographic imaging of disease progression.
Time course ventrodorsal radiographs of representative macaques infected with either H2N2 or H2H3. Panels (A), (B), (C) and (D) represent time course radiographs from an individual animal at baseline, 3 dpi, 8 dpi, and 14 dpi infected with human H2N2 influenza virus. Focal interstitial radiographic changes (solid arrows) were noted on 3 dpi and 8 dpi but have resolved by 14 dpi. Panels (E), (F), (G) and (H) represent time course radiographs from an individual animal at baseline, 3 dpi, 8 dpi, and 14 dpi infected with swine H2N3 influenza virus. Focal interstitial changes with consolidation and partial effacement of the cardiac silhouette (open arrow) were noted. Radiographic changes are progressive on 8 dpi and 14 dpi with complete effacement of the cardiac silhouette and consolidation within the entire right hemi-thorax. Radiographic scoring was performed as previously published [21].
Figure 2.
Gross pathologic lung lesions in H2N2 and H2N3 infected animals.
Gross pathological lung lesions are expressed as the mean percentage of the upper, middle and lower right lung lobe surface covered by lesions (n = 2 per group). Error bars represent standard error of the mean. *significantly different from H2N2, P<0.01; 2-way analysis of variance (ANOVA).
Figure 3.
Histopathology of lung lesions.
Histopathology was performed on samples derived from human H2N2 and swine H2N3 infected animals on 1, 6 and 14 dpi. The left hand columns (panels A, C, E, G, I, K) are H&E stained sections of lung representative of the three time points. The right hand columns are IHC stained lung sections from the same animal and lung lobe as the H&E stained sections. (A) Inflammatory cells (neutrophils and macrophages) and cell debris in a bronchial lumen (asterisk); similar cell population in adjacent alveoli (white arrow). (B) Antibody positive staining in cells of the bronchial lining epithelium with epithelial cell morphology (arrow). Asterisk indicates bronchial lumen. (C) Alveolar type II pneumocyte hyperplasia (black arrowhead) and fibrin in alveoli adjacent to a bronchus. (D) Rare antibody stained cell in bronchial lining epithelium (arrow). (E) Chronic pneumonia (fibroblasts, lymphocytes, plasma cells) with alveolar septal fibrosis (f) and type II pneumocyte hyperplasia (black arrowhead). (F) Absence of antibody staining. (G) Numerous neutrophils and macrophages within alveoli adjacent to a bronchus (white arrow). Asterisk indicates bronchial lumen. (H) Antibody positive stained cells in bronchial lining epithelium (arrow). (I) Fibrin hyaline membrane (open arrowhead); mixed inflammatory cells and thickened alveolar septae. (J) Rare antibody stained cells with macrophage or possible type II pneumocyte morphology (arrow). (K) Chronic pneumonia (fibroblasts, lymphocytes, plasma cells) and organized fibrin (open arrowhead) within alveoli. (L) Absence of antibody stained cells. Key: A, B = animal 635; C, D = animal 479; E, F = animal 358; G. H = animal 805; I, J = 937; K, L animal 745 (for animal numbers see also Table 1).
Figure 4.
Virus replication in upper and lower respiratory tract.
Virus titers were determined by TCID50 assay from nasal swabs and tissue specimens collected during examinations and necropsies, respectively. (A) This part shows titers of nasal swabs over time from human H2N2 and swine H2N3 infected animals. Error bars represent the standard errors of mean from 6 (1 dpi), 4 (3 dpi and 6 dpi) and 2 (8 dpi and 10 dpi) animals. A statistical significant difference in viral titers was observed between the groups by 2 way ANOVA (p = 0.0297). (B) and (C) These parts show titers (individual animals) from tissue specimens taken on 1 dpi and 6 dpi, respectively.
Figure 5.
Plasma cytokine response in Cynomolgus macaques.
Cytokine plasma levels were analyzed by a bioplex assay. (A) Interferon (IFN)γ, (B) Interleukin 6 (IL-6), (C) IL-8, and (D) Monocyte chemotactic protein 1 (MCP-1). Error bars represent the standard error of mean from 6 (1 dpi), 4 (3 dpi and 6 dpi) and 2 (8 dpi and 10 dpi) animals. *significant difference between H2N3 and H2N2 infected animals by t-test; p<0.05).