A) Label retention by CCSP positive cells in airways. Double staining of BrdU and CCSP in the TB (left panel) and BL (middle panel). Barograph demonstrated the quantitative BrdU/CCSP double positive cells in TB and BL (IF, mouse number = 5, total TBs = 49, BLs = 26). B) Bronchioalveolar stem cells (BASCs) in the airway epithelium. CCSP and pro-SPC double immunofluorescence staining. Double positive cells were represented in TB (Left and middle panel, white arrow). Barograph showed the quantitative CCSP/Pro-SPC double positive cells in TB and BL. (IF, mouse number = 7, total TBs = 21, BLs = 20) C) A solitary double CD44/CCSP positive cell in a TB (immunofluorescence staining, bar = 20 µm). D) Sox2 nuclear (immunoperoxidase staining, bar = 100 µm), E) ALDH1 (immunperoxidase staining, bar = 100 µm) F-G) Bar graphs of qRT-PCR analyses for the relative expression of CD133, CD44, Sca-1 and Sox2 mRNAs in mouse lungs (mean±SD).