FIG. 7.

Rare co-localization of mesenchymal and endothelial markers in fetal mouse lung. E15 fetal mouse lung sections were immunostained using antibodies against α-SMA (A, C–F), NG2 (B), Flk-1 (A, D–F), or PECAM-1 (C). Images were then obtained by confocal microscopy. Arrows indicate individual cells that appear to express both an endothelial marker (Flk-1 or PECAM-1) and a mesenchymal marker (α-SMA, NG2). (scale bars in A–C, 25 μm). (D–F) Higher-magnification confocal images with cells positive for both α-SMA and Flk-1 (br=bronchial epithelium, sm=smooth muscle; scale bars 5 μm in D, E, 3 μm in F).