Fig 1: Preventive treatment with OM–85 expands dendritic cells and alveolar macrophages and contributes do antiviral response improvement. Mice were treated intranasally with OM–85 (1mg) 5 days prior to RSV infection (four OM–85 delivery). Afterwards, mice were infected with RSV (1x107 PFU/ml) and received another OM–85 boost 6h later. BAL and lungs were harvested at day 5 post–infection. (A, B) Percentage of CD11c+F4/80–CD207+CD103+ conventional dendritic cells in the lung and its representative FACS profile. (C–F) Percentage of +CD11c+F4/80+Siglec–F+ alveolar macrophages in lung and BAL, and its representative FACS profile. (G) Ifnb1 gene expression in the lungs detected by real–time PCR (fold change compared to untreated/uninfected control). (H) Production of IFNß in the lungs measured by ELISA. (I, J) Isg15 and Ddx58 (RIG–I gene) gene expression in the lungs detected by real–time PCR (fold change compared to untreated/uninfected control). All data are expressed as mean ± SEM. Multiple groups were compared using Kruskal–Wallis. *p < 0.05. **p < 0.01, ***p < 0.001.