摘要：Highly purified Clara cells (93 +/- 3%) isolated from the lungs of rabbits were used to produce an antiserum against Clara cell secretory proteins. This antiserum was used to identify and study the biosynthesis and secretion of [35S]methionine-labeled proteins from isolated Clara cells. The antiserum recognized one major secretory protein with apparent molecular weight of 6 kDa and reacted weakly with a higher molecular weight protein of about 180 kDa. Biosynthesis and secretion of these proteins was not detected in preparations of isolated alveolar type II cells or alveolar macrophages. Immunocytochemical localization of the antigen with colloidal gold indicated a dual localization in bronchiolar Clara cells. Gold labeling was found over the osmiophilic secretory granules of Clara cells and smooth endoplasmic reticulum. In tracheal Clara cells, labeling was found mostly in association with secretory granules and relatively little in association with the smooth endoplasmic reticulum. Labeling was also found over the lamellar bodies of type II cells, although the reaction was weak. Labeling of ciliated cells, alveolar type I cells, capillary endothelial cells, and alveolar macrophages was not distinguishable from background. These data indicate that Clara cells of both the bronchioles and trachea of rabbits synthesize and secrete the low molecular weight protein previously called Clara cell secretory protein (CCSP). This antigen does not belong to that group of surfactant proteins whose molecular weights range from 26 to 40 kDa. Full text Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (3.1M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References . 225 226 227 228 229 230 231 232
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