Hunninghake G W, Gadek J E, Fales H M, Crystal R G
J Clin Invest. 1980 Sep;66(3):473-83. doi: 10.1172/JCI109878.
The presence of neutrophils within the lung is a characteristic feature of a variety of lung diseases. To evaluate the potential role of alveolar macrophages in modulating the migration of neutrophils to the lung, normal human alveolar macrophages obtained from volunteers by bronchopulmonary lavage, were exposed for various periods of time in vitro to heat-killed microorganisms, and noninfectious particulates, immune complexes, and the macrophage supernates were evaluated for chemotactic activity. The microorganisms, noninfectious particulates, and immune complexes were chosen as stimuli for alveolar macrophages because these stimuli are representative of a spectrum of pathogenic agents that cause neutrophil accumulation in the lower respiratory tract. After incubation with each of these stimuli, alveolar macrophages released low molecular weight (400-600) chemotactic factor(s) (alveolar macrophage-derived chemotactic factor[s] [AMCF]) with relatively more activity for neutrophils than monocytes or eosinophils. Checker-board analysis of the AMCF revealed that the factor was primarily chemotactic and not chemokinetic for neutrophils. The selectivity for neutrophils vs. monocytes could not be explained by a selective deactivation of monocytes, because the AMCF was more potent in deactivating neutrophils than monocytes. Partial characterization of AMCF demonstrated it was heterogeneous with the following features: (a) stable to heating at 56 and 100 degrees C for 30 min; (b) stable over a pH range of 1.0 to 12.0 for 60 min; (c) stable after exposure to trypsin, papain, chymotrypsin, collagenase, and elastase; (d) partially inhibited by serum chemotactic factor inhibitor(s); (e) two major isoelectric points (pI 7.6 and 5.2); and (f) partially extractable into ethyl acetate, ether, and hexane. Although AMCF was, at least, partially lipid in nature, it did not appear to be similar to previously described lipid chemotactic factors (e.g., hydroxy-derivatives of 5,8,10,14-eicosatetraenoic acid); analysis by gas chromatography-mass spectrophotometry of AMCF extracted into ethyl acetate did not reveal the presence of 5,8,10,14-eicosatetraenoic acid. The macrophage supernates containing the AMCF also stimulated normal human neutrophils to release lysozyme and lactoferrin but not lactate dehydrogenase. These studies suggest that a wide variety of potentially pathogenic stimuli induce normal alveolar macrophages to generate a low molecular weight chemotactic factor(s) that preferentially attracts neutrophils. Because alveolar macrophages are normal residents of alveoli, it is likely that by releasing this factor(s) macrophages play a significant role in amplifying the inflammatory processes seen in many acute and chronic lung diseases.
肺内中性粒细胞的存在是多种肺部疾病的一个特征性表现。为了评估肺泡巨噬细胞在调节中性粒细胞向肺内迁移中的潜在作用，通过支气管肺泡灌洗从志愿者获取正常人肺泡巨噬细胞，将其在体外与热灭活微生物、非感染性颗粒、免疫复合物接触不同时间，然后评估巨噬细胞培养上清液的趋化活性。选择微生物、非感染性颗粒和免疫复合物作为肺泡巨噬细胞的刺激物，是因为这些刺激物代表了一系列可导致中性粒细胞在下呼吸道积聚的病原体。与这些刺激物中的每一种孵育后，肺泡巨噬细胞释放出低分子量（400 - 600）的趋化因子（肺泡巨噬细胞衍生趋化因子[AMCF]），该因子对中性粒细胞的活性相对高于单核细胞或嗜酸性粒细胞。对AMCF的棋盘分析显示，该因子对中性粒细胞主要是趋化作用而非化学促动作用。中性粒细胞与单核细胞之间的选择性不能用单核细胞的选择性失活来解释，因为AMCF使中性粒细胞失活的作用比单核细胞更强。AMCF的部分特性表明它具有异质性，具有以下特征：（a）在56℃和100℃加热30分钟稳定；（b）在pH值1.0至12.0的范围内60分钟稳定；（c）经胰蛋白酶、木瓜蛋白酶、胰凝乳蛋白酶、胶原酶和弹性蛋白酶处理后稳定；（d）被血清趋化因子抑制剂部分抑制；（e）有两个主要的等电点（pI 7.6和5.2）；（f）可部分提取到乙酸乙酯、乙醚和己烷中。虽然AMCF至少部分具有脂质性质，但它似乎与先前描述的脂质趋化因子（如5,8,10,14 - 二十碳四烯酸的羟基衍生物）不同；对提取到乙酸乙酯中的AMCF进行气相色谱 - 质谱分析未发现5,8,10,14 - 二十碳四烯酸的存在。含有AMCF的巨噬细胞培养上清液还刺激正常人中性粒细胞释放溶菌酶和乳铁蛋白，但不释放乳酸脱氢酶。这些研究表明，多种潜在致病刺激可诱导正常肺泡巨噬细胞产生一种低分子量趋化因子，该因子优先吸引中性粒细胞。由于肺泡巨噬细胞是肺泡的正常驻留细胞，巨噬细胞很可能通过释放这种因子在许多急慢性肺部疾病中所见的炎症过程放大中发挥重要作用。
