Immunohistochemical localization of type I, II, III, and IV collagens in the lung.

Type specific rabbit antibodies to bovine type I, II, III, and IV (basement membrane) collagens showing no cross-reaction with other types of collagen were prepared by cross-adsorption and diethylaminoethyl-cellulose chromatography. The antibodies to bovine type I and III collagens showed a high cross-reaction with the corresponding human collagens, but those to type II and IV collagens did moderate and no cross-reactions with human type II and IV collagens, respectively. By using these antibodies, tissue distribution of various types of collagen in normal bovine lung was examined by indirect immunofluorescence microscopy. both type I and III collagens were found to distribute widely in the interstitium of bronchial tree, bronchial lamina propria and of interlobules as well as alveolar nipples and adventitia of pulmonary arteries. Type II collagen was located only in bronchial cartilage. The tissues mainly stained for type III collagen were the alveolar interstitium (also stained faintly for type I collagen) and the intima and media of the arteries. Type IV collagen was located in a membranous fashion in alveolar septa and bronchial smooth muscles and subepithelial layers as well as capillaries and the intima and media of arteries.