Balis J U, Paterson J F, Paciga J E, Haller E M, Shelley S A
Lab Invest. 1985 Jun;52(6):657-69.
Human surfactant contains lung-specific, high molecular weight glycoproteins which are composed of disulfide-linked 34-kilodalton peptide subunits. We prepared antibodies to both isolated HMW glycoproteins and 34-kilodalton peptides and tested the antisera for specificity with immunochemical procedures. In the present study we have investigated the cellular distribution and subcellular localization of these glycoproteins in surgically excised human lung tissue with or without type II cell hyperplasia. An immunoperoxidase technique was used, and cytoplasmic staining reflecting labeling with antibodies to either high molecular weight glycoproteins or the 34-kilodalton peptide subunits was consistently observed in normal type II cells, Clara cells, and some alveolar macrophages and was more intense and diffuse in hyperplastic type II cells. The ultrastructural localization of surfactant-associated glycoproteins was investigated using the periodate-lysine-paraformaldehyde fixative and a peroxidase-labeled antibody technique. In both normal and proliferating type II cells the staining was localized in the rough endoplasmic reticulum, perinuclear cisternas, vesicles of the Golgi complex, vesicles and lamellar membranes of the multivesicular bodies, and some multivesicular body-lamellar body forms. In addition, staining was frequently found in peripheral portions of partially preserved lamellar bodies including those at the stage of secretion, as well as in association with of alveolar tubular myelin. Labeling was also observed in the rough endoplasmic reticulum of Clara cells. We conclude that antibodies against human surfactant-associated glycoproteins are markers for normal and regenerating type II cells, as well as for Clara cells which apparently retain limited ability to produce surfactant-associated glycoproteins independently of surfactant phospholipids. The results indicate that, in type II cells, synthesis and secretion of these glycoproteins involve the same cytoplasmic organelles that are responsible for synthesis, packaging, storage, and exocytosis of surfactant phospholipids. However, maturation of the lamellar bodies, known to be characterized by progressive accumulation of phospholipids, may not require parallel storage of surfactant-associated glycoproteins within the entire lamellar body compartment.
人表面活性物质含有肺特异性的高分子量糖蛋白，这些糖蛋白由二硫键连接的34千道尔顿肽亚基组成。我们制备了针对分离的高分子量糖蛋白和34千道尔顿肽的抗体，并用免疫化学方法检测抗血清的特异性。在本研究中，我们调查了这些糖蛋白在手术切除的有或无II型细胞增生的人肺组织中的细胞分布和亚细胞定位。采用免疫过氧化物酶技术，在正常II型细胞、克拉拉细胞、一些肺泡巨噬细胞中始终观察到反映用高分子量糖蛋白或34千道尔顿肽亚基抗体标记的细胞质染色，在增生的II型细胞中染色更强且更弥散。使用高碘酸盐-赖氨酸-多聚甲醛固定剂和过氧化物酶标记抗体技术研究了表面活性物质相关糖蛋白的超微结构定位。在正常和增殖的II型细胞中，染色定位于粗面内质网、核周池、高尔基复合体的小泡、多泡体的小泡和板层膜以及一些多泡体-板层体形式。此外，在部分保存的板层体的周边部分，包括分泌阶段的板层体，以及与肺泡管状髓鞘相关的部位，经常发现染色。在克拉拉细胞的粗面内质网中也观察到标记。我们得出结论，针对人表面活性物质相关糖蛋白的抗体是正常和再生II型细胞以及克拉拉细胞的标志物，克拉拉细胞显然保留了独立于表面活性物质磷脂产生表面活性物质相关糖蛋白的有限能力。结果表明，在II型细胞中，这些糖蛋白的合成和分泌涉及与表面活性物质磷脂的合成、包装、储存和胞吐作用相同的细胞质细胞器。然而，已知以磷脂逐渐积累为特征的板层体成熟可能不需要在整个板层体区室内平行储存表面活性物质相关糖蛋白。
