Fig. 2: OPN deficiency reduces virus replication and decreases IAV-induced lung inflammation.

A, B WT mice were infected with PR8 (1.5 × 10³ PFU/animal). Analysis was performed on data collected 24 h post infection. A OPN protein levels in BALF supernatants. B OPN mRNA levels in the lung homogenates. C–H WT mice or OPN^−/− mice were infected with PR8 (1.5 × 10³ PFU/animal). Analysis was performed on data collected 24 h post infection. C Serial lung sections of representative lungs stained with hematoxylin and eosin, scale bar = 100 μm. D The level of tissue injury was quantified from the LDH levels in serum. E BALF was obtained and inflammatory factor (IL-6, MCP-1, and TNF-α) levels in the BALF supernatant were measured using ELISA. F Levels of inflammatory factors (IL-6, MCP-1, and IFN-γ) in lung homogenates were measured using qPCR. G Total viral titers in the lung homogenates were quantified using qPCR. H Lung homogenates were collected and subjected to western blot analysis. Each lane corresponds to an individual mouse. Lane-loading differences were normalized by levels of ACTIN. Data was analyzed by Student’s t test (two-tailed) (A, B, G) or one-way ANOVA (D, E, F, H) and expressed as mean ± SEM. n = 3-7/group. *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001.