Figure 6.

Immunolocalization of cathepsin and cystatin B proteins in BPD. Immunohistochemistry was performed on formalin-fixed, paraffin-embedded lung tissue sections of baboons with BPD using specific antibodies for cat B, H, L, and S, and cystatin B. Methyl green was used as the counterstain. Photomicrographs are representative of the results obtained in a minimum of four experiments using samples from four to five study animals. Scale bar, 100 μm. Shown are cat B immunoreactivity in macrophages (A; black arrow), interstitial cells (B; white arrows), and fibroblasts (C; white arrows); cat H staining in type 2 alveolar epithelial cells (D, E, and F; arrowheads), macrophages (D, E, and F; black arrows), and rare interstitial cells (E; white arrows); cat L immunoreactivity in macrophages (G; black arrows), bronchial epithelial cells in supranuclear localization (H; black arrowhead), vascular (I; black arrow) and lymphatic endothelial cells (J; black arrow), and a fibroblast (J; white arrowhead); cat S staining in macrophages (K and L; black arrows); cystatin B immunoreactivity in type 2 alveolar epithelial cells (M; arrowhead), macrophages (M; black arrow), and bronchial epithelial cells (N) and a bronchial gland (N; black arrowhead); negative control stained with mouse primary antibody isotype control showing no staining in macrophages (O; black arrows).