Bloemen P G, Van den Tweel M C, Henricks P A, Engels F, Van de Velde M J, Blomjous F J, Nijkamp F P
Department of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, The Netherlands.
Am J Physiol. 1996 Jan;270(1 Pt 1):L80-7. doi: 10.1152/ajplung.1996.270.1.L80.
It has become clear that the bronchial epithelium is not just a passive barrier but plays an active role in inflammation. It can produce several inflammatory mediators and does express cell adhesion molecules of which intercellular adhesion molecule (ICAM)-1 can be upregulated by cytokines like interferon (IFN)-gamma. In the present study, we analyzed in detail the interaction of neutrophils with human bronchial epithelial cells, both primary cultured cells and the bronchial epithelial cell line BEAS-2B. Confluent monolayers of epithelial cells were incubated with freshly isolated 51Cr-labeled neutrophils for 30 min at 37 degrees C; then the nonadherent cells were removed by washing gently. Stimulation of the epithelial cells with IFN-gamma or the combination of IFN-gamma and tumor necrosis factor-alpha (TNF-alpha) (which doubles the ICAM-1 expression) increased neutrophil adhesion. Activation of the neutrophils themselves with N-formylmethionyl-leucyl-phenylalanine (fMLP), platelet-activating factor, or TNF-alpha also caused a profound enhancement of the adhesion. A significant additional increase was found when the epithelial cells had been exposed to IFN-gamma and the neutrophils were stimulated with fMLP simultaneously. This effect was even more pronounced with epithelium preincubated with IFN-gamma and TNF-alpha. With the use of monoclonal antibodies against CD18 and ICAM-1, it was demonstrated that the increased adhesion was mainly mediated by the ICAM-1/beta 2-integrin interaction. This study highlights that both the activation state of the bronchial epithelial cells and the activation state of the neutrophils are critical for their interactive adhesion.
现已明确，支气管上皮不仅是一个被动屏障，而且在炎症中发挥着积极作用。它能产生多种炎症介质，并且确实表达细胞黏附分子，其中细胞间黏附分子（ICAM）-1可被干扰素（IFN）-γ等细胞因子上调。在本研究中，我们详细分析了中性粒细胞与人支气管上皮细胞（原代培养细胞和支气管上皮细胞系BEAS-2B）之间的相互作用。将汇合的上皮细胞单层与新鲜分离的51Cr标记的中性粒细胞在37℃下孵育30分钟；然后通过轻轻洗涤去除未黏附的细胞。用IFN-γ或IFN-γ与肿瘤坏死因子-α（TNF-α）联合刺激（可使ICAM-1表达增加一倍）可增加中性粒细胞黏附。用N-甲酰甲硫氨酰-亮氨酰-苯丙氨酸（fMLP）、血小板活化因子或TNF-α激活中性粒细胞本身也会显著增强黏附。当上皮细胞暴露于IFN-γ且中性粒细胞同时受到fMLP刺激时，发现黏附显著进一步增加。对于预先用IFN-γ和TNF-α孵育的上皮细胞，这种效应更为明显。使用针对CD18和ICAM-1的单克隆抗体表明，增加的黏附主要由ICAM-1/β2整合素相互作用介导。本研究强调，支气管上皮细胞的激活状态和中性粒细胞的激活状态对它们的相互黏附都至关重要。
