In conclusion, we have isolated Oct4 + Ccsp + SSEA-1 + expressing progenitor epithelial cells in the bone marrow of swine which are capable of differentiating into type I and II pneumocytes. Additionally, we have demonstrated that these cells serve as targets for influenza virus infection. Further characterization of these progenitor cells may help in understanding the pathogenesis of infectious and non-infectious epithelial diseases and the mechanisms of lung injury repair.