Fig. 4

MSC-EVs inhibit influenza virus replication in lung epithelial cells. Swine/MN/08; H1N1 (SwIV; MOI = 1) was incubated with Dulbecco’s modified Eagle’s medium (DMEM) or 10 μg/ml MSC extracellular vesicles (EVs) for 20 min at room temperature. After the incubation, LECs were inoculated with virus-EV mixture or virus alone and incubated for 1 h at 37 °C. Influenza virus NP was detected at 8 h after infection (a) and SwIV-induced cytopathology was observed at 48 h after infection (b). SwIV-infected cells expressing NP were counted at 8 h after infection. Each bar represents mean ± SD of virus-infected cells in five microscopic fields (20×) (c). Virus titers in supernatants of SwIV-infected and MSC-EV-treated cells at 48 h after infection were determined by titration in MDCK cells. Data are expressed as mean ± SD from three independent experiments using EVs derived from BM-MSCs from three different pigs (d). *P < 0.05