OPN-/- mice are protected from RSV infections.

<p>WT C57BL/6 and OPN-/- mice were intranasally infection with a high dose of mucogenic rA2-L19F (1×10⁶ pfu/mouse, n = 4) or a mock-inoculum, and at 5 and 8 dpi tissues were harvested. Total experiment was performed in triplicate, with data represented as means ±SEM. (A) Total lung RNA was analyzed with qRT-PCR for gene expression of RSV N and displayed as arbitrary relative units. (B) Plaques were obtained from the lung homogenates of infected mice at 5 and 8 dpi. (C) Lung sections (5 µm) were stained for the presence of RSV antigens using a polyclonal antibody and Alexa Fluor 555-secondary antibody and appears as red, while DAPI-stained nuclei appear blue. Images shown are representative of a minimum of 10 images collected at 200X magnification, all collected with identical exposure settings. (D) The number of RSV-positive cells was then calculated by ITCN ImageJ analysis, assuming differential diameters for quantifying the nuclei and individual cells. The percentage of RSV-positive cells is displayed as means ±SEM.