Fig. 6. C/EBP influences maturation of the capillary-epithelial interface. Lung sections from Cebpa^/ mice and control littermates were obtained at E18.5 and immunostained for vWF and -SMA. In controls (A), an extensive vascular network was observed in which vessels are located in close apposition to squamous type I cells. In Cebpa^/ mice (B), a relatively undeveloped capillary bed, with vessels embedded within the thickened mesenchyme of the immature lung saccules, was observed. Expression of -SMA was detected in smooth muscle cells surrounding the bronchioles in both control (C) and Cebpa^/ (D) mice. Scale bar: 50 µm.