Heterogeneous pathological outcomes after experimental pH1N1 influenza infection in ferrets correlate with viral replication and host immune responses in the lung

Vidaña, Beatriz; Martínez, Jorge; Martínez-Orellana, Pamela; García Migura, Lourdes; Montoya, María; Martorell, Jaime; Majó, Natàlia

The animals that developed severe lung lesions exhibited viral antigen expression in bronchi/bronchiole epithelial cells and scattered expression in the alveolar parenchyma. Positive labelling was observed in the nuclei of type II pneumocytes and, to a lesser extent, in the type I pneumocyte nuclei and the nuclei and cytoplasm of macrophages and interstitial lymphocytic cells ( Figure 1 ). In contrast, IAV antigen expression in the animals that developed mild lung lesions was restricted to the bronchi and bronchiolar areas (Figure 1 ), in which IAV antigens were mainly detected in the nuclei of the bronchi or bronchiolar epithelial and glandular cells.