Heparan sulfates in the terminal sac-period of the lung (mouse, fetus)

Stain: fluorescence microscopy with anti-heparan sulphate antibody (a phage-display antibody, LKiv69). Heparan sulfates are linear polysaccharides that belongs to the group of the glycosaminoglycans (GAGs). The sulphated saccharide domains provide numerous docking sites for protein ligands. These GAGs are found associated with basement membranes as shown here. Strong fluorescence visualizes the course of all basement membranes, especially around the bronchioles (B) and around the bundles of smooth muscles (↓). Both subendothelially within the muscular pulmonary artery (PA) and in the adventia fluorescence shows the characteristic double elastic layer of a larger pulmonary artery. In between the positive structures, unstained lymph vessels (Lv) without basement membranes are visible. Note at (A) the reactive lining of the air spaces (future alveoli). GAG-expression pattern changes during tumor development.