Expression and localization of lung surfactant protein A in human tissues
Expression and localization of lung surfactant protein A in human tissues
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DOI：
10.1165/rcmb.2002-0274oc
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发表时间：
2003-11-01
影响因子：
6.4
通讯作者：
Holmskov, U
中科院分区：
文献类型：
--
作者：
Madsen, J;Tornoe, I;Holmskov, U
肺表面活性蛋白A （SP-A）是肺泡11型细胞和Clara细胞产生的一种蛋白集合。它与微生物上的碳水化合物结构结合，启动先天免疫的效应机制并调节肺部的炎症反应。逆转录-聚合酶链反应对一组来自人体组织的rna进行SP-A mRNA表达。肺是主要的合成部位，但也可以从气管、前列腺、胰腺和胸腺中扩增出转录本。结肠和唾液腺均有弱表达。来自肺和胸腺mRNA的SP-A序列显示SP-A1和SP-A2均存在，而SP-A2仅在气管和前列腺中表达。制备了针对SP-A的单克隆抗体并进行了鉴定。其中一种（hyb238 -4）在Western blotting中与还原的和未还原的SP-A、n -去糖基化和胶原酶处理的SP-A以及重组SP-A1和SP-A2反应。该抗体用于证明SP-A在人体组织免疫组织化学中的作用。在肺泡ii型细胞、Clara细胞以及肺泡巨噬细胞表面和内可见较强的SP-A免疫反应，但肺外未见SP-A免疫反应。与通常在粘膜表面表达的肺表面活性蛋白D （SP-D）相反，SP-A似乎仅限于呼吸系统。
Lung surfactant protein A (SP-A) is a collectin produced by alveolar type 11 cells and Clara cells. It binds to carbohydrate structures on microorganisms, initiating effector mechanisms of innate immunity and modulating the inflammatory response in the lung. Reverse transcriptase-polymerase chain reaction was performed on a panel of RNAs from human tissues for SP-A mRNA expression. The lung was the main site of synthesis, but transcripts were readily amplified from the trachea, prostate, pancreas, and thymus. Weak expression was observed in the colon and salivary gland. SP-A sequences derived from lung and thymus mRNA revealed the presence of both SP-A1 and SP-A2, whereas only SP-A2 expression was found in the trachea and prostate. Monoclonal antibodies were raised against SP-A and characterized. One of these (HYB 238-4) reacted in Western blotting with both reduced and unreduced SP-A, with N-deglycosylated and collagenase-treated SP-A, and with both recombinant SP-A1 and SP-A2. This antibody was used to demonstrate SP-A in immunohistochemistry of human tissues. Strong SP-A immunoreactivity was seen in alveolar type-II cells, Clara cells, and on and within alveolar macrophages, but no extrapulmonary SP-A immunoreactivity was observed. In contrast to lung surfactant protein D (SP-D), which is generally expressed on mucosal surfaces, SP-A seems to be restricted to the respiratory system.