Cheng G, Ueda T, Eda F, Arima M, Yoshida N, Fukuda T
Department of Pulmonary Medicine and Clinical Immunology, Dokkyo University School of Medicine, Tochigi, Japan.
Am J Respir Cell Mol Biol. 2001 Aug;25(2):212-8. doi: 10.1165/ajrcmb.25.2.4270.
Alveolar epithelial cells produce many types of chemokines such as regulated on activation, normal T cells expressed and secreted (RANTES), eotaxin induced by interleukin (IL)-1 beta, or tumor necrosis factor (TNF)-alpha and may contribute to allergic disease by recruiting eosinophils. However, identification of the eosinophil chemotacic activity (ECA) release from A549 cells, an alveolar type II cell line, has not yet been completed. Recently, IL-16 was also reported to be a potent chemotactic stimulus for CD4(+) T lymphocytes and eosinophils in asthma and other pulmonary diseases. To test the possibility that alveolar epithelial cells produce IL-16, we analyzed RNA and culture supernatant from A549 cells by reverse transcription/ polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). The release of ECA from A549 cells was assessed using a blind-well chemotactic chamber. IL-16 release was increased in a concentration-dependent manner by stimulation with IL-1 beta or TNF-alpha. A549 cells also expressed IL-16 messenger RNA. The combination of IL-4 and IL-1 beta or TNF-alpha had an additive effect on IL-16 production. The release of ECA was induced by IL-1 beta or TNF-alpha in a dose-dependent manner. The combination of these cytokines had a greater effect than one alone. The blockade of eotaxin and IL-16 caused 70% inhibition of ECA, but anti-RANTES antibodies only caused 30% inhibition and anti-IL-8 antibodies failed to affect inhibition. These findings suggest a role for chemokines released by alveolar epithelial cells in the recruitment of eosinophils into the lung in pulmonary disorders such as asthma and interstitial lung diseases, and suggested that eotaxin and IL-16 are potent and effective eosinophil chemoattractants.
肺泡上皮细胞可产生多种趋化因子，如正常T细胞激活后表达和分泌的调节激活正常T细胞表达和分泌因子（RANTES）、白细胞介素（IL）-1β或肿瘤坏死因子（TNF）-α诱导的嗜酸性粒细胞趋化因子，并且可能通过募集嗜酸性粒细胞而导致过敏性疾病。然而，肺泡Ⅱ型细胞系A549细胞释放嗜酸性粒细胞趋化活性（ECA）的鉴定工作尚未完成。最近，有报道称IL-16在哮喘和其他肺部疾病中也是CD4(+)T淋巴细胞和嗜酸性粒细胞的有效趋化刺激物。为了验证肺泡上皮细胞产生IL-16的可能性，我们通过逆转录/聚合酶链反应（RT-PCR）和酶联免疫吸附测定（ELISA）分析了A549细胞的RNA和培养上清液。使用盲孔趋化小室评估A549细胞ECA的释放。用IL-1β或TNF-α刺激后，IL-16的释放呈浓度依赖性增加。A549细胞也表达IL-16信使RNA。IL-4与IL-1β或TNF-α联合对IL-16的产生有相加作用。IL-1β或TNF-α以剂量依赖性方式诱导ECA的释放。这些细胞因子联合使用比单独使用的效果更佳。嗜酸性粒细胞趋化因子和IL-16的阻断导致ECA抑制70%，但抗RANTES抗体仅导致30%的抑制，而抗IL-8抗体未能影响抑制作用。这些发现表明，肺泡上皮细胞释放的趋化因子在哮喘和间质性肺疾病等肺部疾病中嗜酸性粒细胞向肺内的募集中发挥作用，并提示嗜酸性粒细胞趋化因子和IL-16是有效的嗜酸性粒细胞趋化剂。
