McCray P B, Bentley L
Department of Pediatrics, University of Iowa College of Medicine, Iowa City 52242, USA.
Am J Respir Cell Mol Biol. 1997 Mar;16(3):343-9. doi: 10.1165/ajrcmb.16.3.9070620.
Recent evidence suggests that the surface fluid secreted by human airway epithelial cells contains antimicrobial activity. The identification of the factor(s) responsible for the antibacterial activity in airway surface fluid may bring new insights into lung defense mechanisms and the pathogenesis of disease. Defensins are small cationic peptides with broad-spectrum antimicrobial activity, and are therefore candidates for the bacterial killing factor in airway surface fluid. They are produced in mucosal epithelia and neutrophils of several species. To date no defensins have been isolated from human airway epithelia; however, such peptides are produced by bovine airway epithelia. A cDNA fragment for a human beta-defensin-1 (hBD-1) was recently cloned from the kidney. We cloned the full-length coding sequence for hBD-1 from human airway epithelia. The amino acid sequence for hBD-1 shared homology with the signal/propiece and mature peptides of other beta-defensins, including bovine tracheal antimicrobial peptide and lingual antimicrobial peptide. By Northern analysis, a single approximately 400-nt hBD-1 transcript was expressed in airway epithelia. Ribonuclease protection analysis demonstrated that hBD-1 transcripts were more abundant in the conducting airways than the gas exchange regions of human lung and that the expression was developmentally regulated. Human beta-defensin-1 may contribute to the antimicrobial activity of airway surface fluid and play a role in the mucosal defenses of the lung.
最近的证据表明，人气道上皮细胞分泌的表面液体具有抗菌活性。鉴定气道表面液体中负责抗菌活性的因子可能会为肺部防御机制和疾病发病机制带来新的见解。防御素是具有广谱抗菌活性的小阳离子肽，因此是气道表面液体中细菌杀伤因子的候选者。它们在几种物种的粘膜上皮细胞和中性粒细胞中产生。迄今为止，尚未从人气道上皮细胞中分离出防御素；然而，这种肽是由牛气道上皮细胞产生的。最近从肾脏中克隆了人β-防御素-1（hBD-1）的cDNA片段。我们从人气道上皮细胞中克隆了hBD-1的全长编码序列。hBD-1的氨基酸序列与其他β-防御素的信号/前体和成熟肽具有同源性，包括牛气管抗菌肽和舌抗菌肽。通过Northern分析，在气道上皮细胞中表达了一个约400 nt的单一hBD-1转录本。核糖核酸酶保护分析表明，hBD-1转录本在人类肺的传导气道中比气体交换区域更丰富，并且其表达受发育调控。人β-防御素-1可能有助于气道表面液体中的抗菌活性，并在肺部的粘膜防御中发挥作用。
