Girod C E, Shin D H, Hershenson M B, Solway J, Dahl R, Miller Y E
Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Health Sciences Center, Denver 80262, USA.
Am J Respir Cell Mol Biol. 1996 Jun;14(6):538-47. doi: 10.1165/ajrcmb.14.6.8652182.
The epithelium of the alveolus and distal airway meets unique requirements, functioning as a gas exchange membrane and barrier to alveolar flooding by vascular contents as well as to bloodstream contamination by airborne toxins and pathogens. Gene products specifically expressed by this epithelium, notably the surfactant apoproteins, have had important clinical application. No cell surface antigen specific for alveolar type II and Clara cells has been described. We report the biochemical characterization, tissue and developmental expression, and upregulation by injury of a 172 kD protein recognized by a monoclonal antibody, 3F9, synthesized in response to immunization with freshly isolated rat alveolar type II cells. p172 is expressed in a polarized fashion by the apical surface of rat alveolar type II and Clara cells. An immunohistochemical survey of various rat tissues and organs reveals lung specificity. p172 is first detectable in rare epithelial cells at 19 days of gestation, a time when the fully differentiated alveolar type II cell is identified by the first detection of lamellar bodies. There is a dramatic increase in p172 expression just prior to birth. Hyperoxic lung injury results in increased expression of p172. The upregulation of p172 by hyperoxia and its cell-specific expression suggests an important adaptive function.
肺泡和远端气道的上皮细胞有独特的需求，它作为气体交换膜，既能防止血管内容物导致肺泡积水，又能抵御空气传播的毒素和病原体对血流的污染。这种上皮细胞特异性表达的基因产物，尤其是表面活性蛋白，已经有了重要的临床应用。尚未发现针对II型肺泡细胞和克拉拉细胞的细胞表面抗原。我们报告了一种172 kD蛋白的生化特性、组织和发育表达情况，以及在新鲜分离的大鼠II型肺泡细胞免疫后，由单克隆抗体3F9识别的该蛋白受损伤后的上调情况。p172在大鼠II型肺泡细胞和克拉拉细胞的顶端表面呈极化方式表达。对各种大鼠组织和器官的免疫组织化学研究显示其具有肺特异性。p172在妊娠19天时在罕见的上皮细胞中首次可检测到，此时通过首次检测板层小体可识别出完全分化的II型肺泡细胞。在出生前p172的表达会急剧增加。高氧肺损伤会导致p172表达增加。高氧对p172的上调及其细胞特异性表达表明其具有重要的适应性功能。
