Electron microscopic demonstration of a saccharide moieties in the hypophase of the alveolar surfactant system

For electron microscopic demonstration of complex carbohydrates and simple sugars in the mouse lung, anionic dye and lectins were used. After immersion fixation of small lung tissue blocks, the alveolar surfactant system was destroyed and only membrane bound carbohydrates (cell coat) could be demonstrated by means of colloidal iron and ruthenium red. Fixation of the whole lung via the visceral pleura preserved the alveolar surfactant system. Only this technique afforded a distinction between cell coat components and hypophase components. After performance of the Concanavalin A-peroxidase technique and after incubation in ferritin-labed Concanavalin A, Lens culinaris lectin or Ricinus communis lectin, various saccharide moieties were demonstrable by immune electron microscopy in the hypophase of the alveolar surfactant system.