SURFACTANT PROTEIN-D - SUBCELLULAR-LOCALIZATION IN NONCILIATED BRONCHIOLAR EPITHELIAL-CELLS
SURFACTANT PROTEIN-D - SUBCELLULAR-LOCALIZATION IN NONCILIATED BRONCHIOLAR EPITHELIAL-CELLS
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DOI：
10.1152/ajplung.1992.263.1.l60
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发表时间：
1992-07-01
影响因子：
--
通讯作者：
PERSSON, A
中科院分区：
文献类型：
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作者：
CROUCH, E;PARGHI, D;PERSSON, A
表面活性剂蛋白D（SP-D，CP 4）是一种胶原表面活性剂相关的碳水化合物结合蛋白，最初被鉴定为II型肺细胞的生物合成产物。甲醛溶液固定和石蜡包埋的大鼠肺的免疫过氧化物酶的研究表明染色SP-D的细支气管上皮细胞以及II型细胞的亚群的细胞质中。因此，免疫胶体金标记技术被用来进一步检查SP-D在小气道中的细胞分布和亚细胞定位。肺组织用0.5%戊二醛-3%多聚甲醛固定，并包埋在LR白色树脂中。将切片与亲和纯化的SP-D多克隆抗体反应，并使用生物素化的二抗-链霉亲和素-金检测系统证明抗体结合位点。抗SP-D选择性装饰分泌室的无纤毛细支气管细胞（克拉拉细胞）与强大的和特定的标记顶端电子致密分泌颗粒。几乎所有的颗粒无纤毛柱状细胞标记，然而，标记通常是不均匀的，优先装饰的颗粒的周边。在远端膜性细支气管中观察到最大数量的免疫反应性上皮细胞，在更近端的细支气管中细胞数量逐渐减少。在大的软骨气道或气管中没有可检测到的细胞标记。这些研究为SP-D是无纤毛细支气管细胞的分泌产物提供了证据。我们认为，克拉拉细胞衍生的SP-D是细支气管衬里材料的一个组成部分，与我们的假设，即SP-D有助于表面活性剂代谢和/或宿主防御小气道。
Surfactant protein D (SP-D, CP4) is a collagenous surfactant-associated carbohydrate binding protein that was initially characterized as a biosynthetic product of type II pneumocytes. Immunoperoxidase studies of formaldehyde solution-fixed and paraffin-embedded rat lung demonstrated staining for SP-D in the cytoplasm of a subpopulation of bronchiolar epithelial cells as well as type II cells. Accordingly, immunogold-labeling techniques were used to further examine the cellular distribution and subcellular localization of SP-D in the small airways. Lung tissues were fixed with 0.5% glutaraldehyde-3% paraformaldehyde and embedded in LR White resin. Sections were reacted with affinity purified polyclonal antibodies to SP-D, and sites of antibody binding were demonstrated using a biotinylated secondary antibody-streptavidin-gold detection system. Anti-SP-D selectively decorated secretory compartments of nonciliated bronchiolar cells (Clara cells) with strong and specific labeling of apical electron-dense secretory granules. Almost all of the granules in nonciliated columnar cells were labeled; however, labeling was typically nonuniform, with preferential decoration of the periphery of the granule. The largest numbers of immunoreactive epithelial cells were observed in the distal membranous bronchioles, with progressively smaller numbers of cells in more proximal bronchioles. There was no detectable labeling of cells lining the large cartilagenous airways or trachea. These studies provide evidence that SP-D is a secretory product of nonciliated bronchiolar cells. We suggest that Clara cell-derived SP-D is a component of bronchiolar lining material, consistent with our hypothesis that SP-D contributes to surfactant metabolism and/or host defense within small airways.