Host defense mechanism by pulmonary surfactant proteins A and D thiir clinical application

本研究旨在探讨肺表面活性物质蛋白SP-A和SP-D在机体防御中的分子机制及其临床应用价值。(1)将大鼠Thr 174-Gly 194的SP-A区替换为Thr 164-Asp 184的MBP-A区，构建的SP-A/MBP-A嵌合体丧失了SP-A结合DPPC、Ca 2+依赖性GalCer结合和与肺泡II型细胞相互作用的功能，但获得了结合PI的MBP活性。对应于该SP-A区域的合成肽用于与LPS和肽聚糖相互作用。(2)SP-A和SP-D分别与CD 14的肽部分和寡糖部分相互作用。SP-A和SP-D改变了CD 14与LPS的相互作用。(3)ARDS患者支气管肺泡灌洗液中SP-A水平显著降低，而SP-D水平无显著变化。没有表现出低SP-A水平的有ARDS风险的患者没有发展成ARDS。(4)血清SP-A和SP-D的检测反映了小细胞肺癌的发病机制。 关于我们 胶原血管病患者的间质性病变，胸部CT可以检测到，而胸部X线平片不能检测到。(5)利用CHO-K1细胞和pEE 14载体，利用谷氨酰胺合成酶系统，建立了重组SP-A和SP-D的大规模生产体系。(6)糖尿病大鼠支气管肺泡灌洗液中SP-A和SP-D含量增加，提示SP-A和SP-D起急性期反应物的作用。(7)通过对SP-A/SP-D嵌合体的分析，已经确定羧基端25个氨基酸是SP-A和SP-D与其配体相互作用所必需的。(8)检测肺腺癌患者骨髓中SP-A的表达。SP-A的表达（免疫组化染色及mRNA表达）与角蛋白表达之间存在显著相关性。骨髓SP-A阳性者肿瘤纤维化评分、血管浸润评分高，Noguchi分型为C-F型，提示SP-A表达对肺腺癌微转移的检测有一定意义。少

The purpose of this study were to investigate the molecular mechanism of host defense by pulmonary surfactant proteins SP-A and SP-D and to establish the application for their clinical uses.(1) The SP-A/MBP-A chimera in which the rat SP-A region of Thr174-Gly194 was replaced with the MBP-A region of Thr164-Asp184 lost the SP-A functions of DPPC binding, Ca2+-dependent GalCer binding and interacting with alveolar type II cells but acquired the MBP activity of binding PI. The synthetic peptide corresponding to this SP-A region was used to interact with LPS and peptideglycans.(2) SP-A and SP-D interact with the peptide portion and the oligosaccharide moieties of CD14, respectively. SP-A and SP-D altered the interaction of CD14 with LPS.(3) The SP-A levels but not the SP-D levels significantly decreased in BAL fluids of patients with ARDS. The patients with ARDS at risk that did not exhibit low SP-A levels did not develop ARDS.(4) The detection of serum SP-A and SP-D reflected the small in … More terstitial pathological changes of patients with collagen vascular diseases that might be detected by chest CT but not by plain chest Xp.(5) The large scale production system of recombinant SP-A and SP-D was established by CHO-K1 cells and pEE14 vectors using glutamine synthetase system.(6) The contents of SP-A and SP-D increased in BAL fluids of rats with diabetes mellitus, suggesting that SP-A and SP-D function as acute phase reactants.(7) The carboxy terminal 25 amino acids have been identified to be essential for the interactions of SP-A and SP-D with their ligands by analysis with SP-A/SP-D chimeras.(8) The SP-A expression was examined in bone marrow of patients with primary lung adenocarcinomas. There were significant correlations between expressions of SP-A (immunostaining and mRNA) and cytokeratin. The patients with SP-A positive in bone marrow tend to show high scores of tumor fibrosis and of vessel invasion, and C-F types of Noguchi classification, suggesting the usefulness of SP-A expression to detect micrometastasis of lung adenocarcinomas. Less