Immunocytochemical localization of surfactant protein D (SP-D) in type II cells, Clara cells, and alveolar macrophages of rat lung.

摘要: We investigated the cellular and subcellular distribution of surfactant protein D (SP-D) by immunogold labeling in lungs adult rats that had been given bovine serum albumin coupled to 5-nm gold (BSAG) for 2 hr visualize endocytotic pathway. Specific SP-D was found alveolar Type II cells, Clara macrophages. In cells abundant observed endoplasmic reticulum, whereas Golgi complex multivesicular bodies were labeled a limited extent only. Lamellar did not seem contain SP-D. Gold macrophages restricted structures containing endocytosed BSAG. complex, most prominent granules present apical domain cell. Double experiments with anti-surfactant A (SP-A) showed both SP-A same granules. However, distributed throughout granule contents, confined periphery granule. The cell are considered secretory lysosomes, because they lysosomal markers cathepsin LGP120,