Glycoconjugates on the Surface of the Pulmonary Epithelial Cells in Surfactant Free Rat Lungs

Glycoconjugates on the cell surface of type I and type II pulmonary epithelial cells were examined after airway irrigation by means of colloidal iron (CI), high iron diamine (HID) and ferritin-conjugated lectin stainings, in combination with digestion with carbohydrate-degrading enzymes, methylation or extraction with acid ethanol. The acid saccharide on the surface of type I cells was sialic acid, but the surface of type II cells contained a mixture of a large amount of sialic acid and a small amount of sulfated saccharide. As to the sensitivity on acid ethanol extraction, the sialo-oligosaccharide on type I cells differed from that on type II cells, although the terminal trisaccharides of sialo-oligosaccharides on the both type I and II cells were sialic acid → galactose → N-acetylgalactosamine. Sulfated saccharide, being mainly composed of glucuronic acid and N-acetylgalactosamine, distributed on the surface of the microvilli of type II cells. As to the constituents of glycoconjugates, large amounts of N-acetylglucosamine, galactose, mannose and glucose were found on type I cells, but type II cells had only small amounts of N-acetylglucosamine, mannose and glucose, and a minute amount of galactose.

Iwatsuki H.