RS Virus-Induced Inflammation and the Intracellular Glutathione Redox State in Cultured Human Airway Epithelial Cells

There is ample evidence that asthma is mediated by oxidative stress and that viral infection, which is associated with asthma onset and exacerbation in infants, acts as one type of oxidative stress. The goal of this study was to determine whether respiratory syncytial virus (RSV) induces oxidative stress in cultured A549 human airway epithelial cells and normal human bronchial epithelial cells (NHBE), and whether such RSV-induced oxidative stress can induce airway inflammation. To evaluate the direct effect of RSV infection as an oxidative stressor, the intracellular levels of reduced glutathione (GSH) or oxidized glutathione (GSSG) were measured. Their ratio (GSH/GSSG) was calculated to indicate intracellular oxidation–reduction (redox) status in A549 and NHBE. To evaluate the extent to which glutathione redox regulation affected cytokine/chemokine production, the effect of pretreatment with a reductive agent, glutathione monoethyl ester (GSH-OEt) and RSV-specific monoclonal antibody was thus studied. RSV acted as a potent oxidative stressor on the intracellular glutathione redox state in human airway epithelial cells, activating signals to increase the production of cytokine/chemokine. Pretreatment with GSH-OEt significantly suppressed RSV-induced time-dependent changes in the intracellular redox state, and also suppressed RSV-induced up-regulation of epithelial cell-derived IL-8, IL-6 and eotaxin production, as well as RSV-specific monoclonal antibody. RSV-induced oxidative stress is likely to contribute to the perpetuation and amplification of the inflammatory response. Therapeutic intervention against oxidative stress might therefore be beneficial as adjunctive therapies for respiratory disorders that are caused by an RSV infection.     

Induction of intercellular adhesion molecule-1 in human nasal epithelial cells during respiratory syncytial virus infection.

The effects of infection with respiratory syncytial virus (RSV) on expression of intercellular adhesion molecule (ICAM)-1 was determined in vitro in nasal epithelial cell cultures. Functional consequences of changes in ICAM-1 expression were assessed by measuring adhesion of a human leukaemic T-cell line to RSV-infected epithelial cells. Also, adhesion of phytohaemagglutinin-activated tonsillar lymphocytes (TL) to RSV-infected epithelial cells caused a significant increase in interleukin (IL)-4 or IL-5 production. Release of these cytokines was adhesion dependent as non-adherent TL produced significantly less IL-4 or IL-5. However, no significant difference was observed for IL-2 or interferon-gamma (IFN-gamma) production. These observations suggest that RSV-infected epithelial cells may induce T-helper type-2 (Th2)-like cytokines by mucosal lymphocytes during mucosal infection in vivo.     

Autocrine regulation of interleukin-8 by interleukin-1alpha in respiratory syncytial virus-infected pulmonary epithelial cells in vitro.

Respiratory epithelial cells infected with respiratory syncytial virus (RSV) produce interleukin-8 (IL-8); however, the mechanisms of RSV-induced regulation of IL-8 are poorly understood. In the present study, the regulation of IL-8 by RSV was evaluated using pulmonary type II-like epithelials (A549). Live purified RSV (pRSV) induced a significant increase in IL-8 after 8 hr of exposure, while conditioned supernatants from pRSV-infected A549 cells (cRSV) induced IL-8 production in fresh A549 cultures within 4 hr of infection. Furthermore, cRSV that had been rendered non-infectious by ultraviolet-irradiation (UV-cRSV) or ribavirin treatment also induced an increased production of IL-8 in fresh A549 cells, suggesting that RSV induced the synthesis of a soluble mediator(s) which in turn enhanced the synthesis of IL-8. We have previously shown that RSV-infected A549 cells produce IL-1alpha, IL-1-beta and tumour necrosis factor-alpha (TNF-alpha), which by themselves are known to induce the synthesis of IL-8. Preincubation of UV-cRSV or simultaneous incubation of pRSV with recombinant IL-1 receptor antagonist almost completely blocked (95-98%) the production of IL-8 by A549 cells. Furthermore, incubation with neutralizing antibodies against IL-1alpha, IL-1beta and TNF-alpha showed that IL-1alpha was the predominant soluble mediator that enhanced the mRNA expression and synthesis of IL-8. IL-1beta and TNF-alpha induced the synthesis of IL-8 at 24 hr, but partially inhibited the synthesis at 48 hr. In summary, these experiments provide direct evidence for an autocrine mechanism of enhanced IL-8 production in RSV-infected epithelial cells that is primarily mediated by IL-1alpha. In clinical settings, inhibitors of IL-1alpha may be useful in suppressing inflammation due to IL-1alpha as well as IL-8.     

Mast cell degranulation is induced by A549 airway epithelial cell infected with respiratory syncytial virus

Respiratory syncytial virus (RSV), a major causative agent of respiratory tract infections, influences allergic diseases. Mast cells, important effector cells in allergic disease, also express chemokine (C-X₃-C motif) receptor 1 (CX₃CR1). The RSV attachment glycoprotein (G protein) is structurally similar to CX₃C ligand 1 (CX₃CL1), the CX₃CR1 ligand, suggesting that RSV directly interacts with and affects mast cell function, including degranulation. In this paper, the effect of RSV infection on mast cell function was studied using the human mast cell line (HMC-1). The results showed that RSV infection and replication was inefficient in HMC-1 cells than in human epithelial A549 cells. Additionally, HMC-1 degranulation occurred only in coculture with RSV-infected A549 cells, with up-regulation of TNFα secretion. However, direct RSV inoculation and incubation with RSV-infected A549 cell culture medium failed to induce HMC-1 degranulation, suggesting that virus-infected cells are critical for degranulation during RSV infection; however, degranulation does not occur by direct RSV infection into mast cells.     

5,7-Dihydroxy-3,4,6-trimethoxyflavone inhibits intercellular adhesion molecule 1 and vascular cell adhesion molecule 1 via the Akt and nuclear factor-κB-dependent pathway, leading to suppression of adhesion of monocytes and eosinophils to bronchial epithelial cells

5,7-Dihydroxy-3',4',6'-trimethoxyflavone (eupatilin), the active pharmacological ingredient from Artemisia asiatica Nakai (Asteraceae), is reported to have a variety of anti-inflammatory properties in intestinal epithelial cells. However, little information is known about the molecular mechanism of eupatilin-induced attenuation of bronchial epithelial inflammation. This study investigates the role of eupatilin in the adhesion of inflammatory cells such as monocytes and eosinophils to bronchial epithelial cells. Stimulation of a human bronchial epithelial cell line (BEAS-2B) with tumour necrosis factor-α (TNF-α) increased the expression of surface adhesion molecules, including intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), in which eupatilin significantly inhibited the expression of those adhesion molecules in a dose-dependent manner. Eupatilin suppressed the TNF-α-induced activation of IκBα and nuclear factor-κB (NF-κB) signals in BEAS-2B cells. The IκB kinase (IKK) activation was also significantly reduced in eupatilin-pre-treated BEAS-2B and primary normal human bronchial epithelial (NHBE) cells. However, eupatilin did not influence AP-1 activity in TNF-α-stimulated cells. Suppression of NF-κB signalling induced by eupatilin resulted in the inhibition of the expression of adhesion molecules and the adhesion of monocytes and eosinophils to BEAS-2B cells. Furthermore, eupatilin suppressed the phosphorylation of Akt in TNF-α-stimulated BEAS-2B and NHBE cells, leading to down-regulation of NF-κB activation and adhesion molecule expression and finally to suppression of the inflammatory cell adhesion to epithelial cells. These results suggest that eupatilin can inhibit the adhesion of inflammatory cells to bronchial epithelial cells via a signalling pathway, including activation of Akt and NF-κB, as well as expression of adhesion molecules.     

Cetirizine counter-regulates interleukin-8 release from human epithelial cells (A549)

BACKGROUND: Cetirizine, a H1-receptor antagonist, exerts besides its well-known anti-allergic potential an array of anti-inflammatory activities. In particular epithelial cells activated in the presence of cetirizine showed a reduced ICAM-1 cell surface expression and a diminished release of sICAM-1. OBJECTIVE: We wondered whether cetirizine might influence the release of interleukin-8 (IL-8) from human epithelial cells activated with agonists distinct from histamine. METHODS: We used the human lung epithelial cell line A549 for our in vitro studies. IL-8 release was determined by IL-8 enzyme immunoassay, the intracellular staining for IL-8 and NF-kB was analysed by FACS analysis and IL-8 mRNA steady state level was studied by Northern blot analysis. Confluent epithelial cell monolayer were pre-incubated with cetirizine (0.01 -1.0 micromol/L) for 30 min and afterwards activated with pro-inflammatory cytokines (TNF-alpha IL-1beta, IL-6, IFN-gamma) or different agonists (PMA, NaF, respiratory syncytial virus [RSV]) for 24 h. RESULTS: Epithelial cells stimulated with TNF-alpha IL-1beta, PMA and RSV, respectively, showed a significantly increased release of IL-8. Pre-incubation with cetirizine diminished the IL-8 release from cells activated with TNF-alpha or PMA in a significant manner. The reduced IL-8 release coincided with a diminished percentage of cells expressing IL-8. Northern blot analysis revealed a reduced steady state level of IL-8 mRNA in cells pretreated with cetirizine and stimulated with TNF-alpha. Furthermore, a decreased amount of accessible DNA-binding sites of the nuclear factor kappa B (NF-kB) was determined by FACS analysis. CONCLUSIONS: These results suggest that cetirizine reduced the release of IL-8 from A549 cells stimulated with PMA and TNF-alpha, respectively, by lowering IL-8 gene expression. Therefore, cetirizine might exert anti-inflammatory effects beyond its H1-receptor antagonistic activity in the course of inflammatory respiratory tract disorders such as bronchial asthma and allergic rhinitis.     

Mechanism of bronchoprotective effects of a novel natriuretic hormone peptide

BACKGROUND: The natriuretic hormone peptide (NHP)(99-126), a C-terminal peptide of pro-atrial natriuretic factor (proANF), induces bronchodilatory effects in people with asthma. Recently, another plasmid-encoded C-terminal peptide, pNHP(73-102), was shown to induce a long-lasting bronchoprotective effect in a mouse model of allergic asthma. OBJECTIVE: This study was carried out to determine the role of lung epithelial cells in the bronchoprotective and anti-inflammatory activity of these peptides. METHODS: Human type II alveolar epithelial cells (A549) and normal human bronchial epithelial (NHBE) cells were transfected with pNHP(73-102) to test the effect of this peptide on activation of these cells. After transfection, cells were analyzed for changes in Ca(++) and nitric oxide (NO) levels. Also, activation of NFkappaB and the extracellularly regulated kinase (ERK) 1, 2 signaling pathway was examined by luciferase reporter assay and phosphorylation studies respectively. RESULTS: Analysis of intracellular Ca(++) levels in pNHP(73-102) -transfected A549 or NHBE showed that the peptide increases release. This Ca(++) release was accompanied by an increase in the production of NO. Also, overexpression of pNHP(73-102), but not pVAX control, in phorbol myristate acetate-activated A549 cells resulted in a significant decrease in expression of a cotransfected nuclear factorkappaB (NFkappaB)-luciferase reporter. Similarly, pNHP(73-102) decreased TNF-alpha-induced NFkappaB activation in NHBE cells. Furthermore, NHP(73-102) but not atrial natriuretic peptide decreased phosphorylation of Erk-1, 2 in A549 cells. CONCLUSIONS: Overexpression of pNHP(73-102) in epithelial cells causes increased production of intracellular Ca(++) and NO, with a concomitant decrease in activation of NFkappaB and ERK1, 2. These results suggest a bronchodilatory and anti-inflammatory activity of this peptide.     

呼吸道合胞病毒感染人肺上皮细胞活化Toll样受体3介导的抗病毒作用研究

目的 探讨呼吸道合胞病毒( RSV)感染人肺上皮A549细胞后,Toll样受体3(TLR3)的水平变化及其产生的Ⅰ型干扰素的抗病毒作用.方法 RSV感染体外培养的人肺上皮A549细胞,并给予TLR3特异性抗体处理,分别感染4、8、12、16、24h后收集各组细胞.未感染病毒的细胞作为对照组.RT-PCR法检测TLR3、IFN-α、IFN-β,RSV F蛋白的mRNA表达水平变化.结果 RSV感染A549细胞后,TLR3、IFN-α、IFN-β,RSV F蛋白的mRNA表达量均升高且有时间依赖性,TLR3 mRNA在24h表达量是基础表达量的5倍,IFN-α、IFN-β mRNA在24 h表达量是基础表达量的4倍多,RSVF蛋白的mRNA表达量近1.7倍.TLR3抗体预先处理以抑制TLR3受体,再行RSV感染,IFN-α和IFN-β mRNA表达量虽然升高,但较感染组均有所下降,mRNA表达在12 h后显著降低,且IFN-ββ的mRNA表达量下调更明显.但RSV F基因的mRNA表达在12 h、24 h升高有显著性差异.结论 RSV感染A549细胞后可上调TLR3表达,其活化细胞介导产生的Ⅰ型干扰素起抗病毒作用,在一定程度上可抑制病毒的增殖水平.     

Effect of desloratadine and loratadine on rhinovirus-induced intercellular adhesion molecule 1 upregulation and promoter activation in respiratory epithelial cells

BACKGROUND: Rhinoviruses have been recently associated with the majority of asthma exacerbations for which current therapy is inadequate. Intercellular adhesion molecule 1 (ICAM-1) has a central role in airway inflammation in asthma, and it is the receptor for 90% of rhinoviruses. Rhinovirus infection of airway epithelium induces ICAM-1. Desloratadine and loratadine are compounds belonging to the new class of H(1)-receptor blockers. Anti-inflammatory properties of antihistamines have been recently documented, although the underlying molecular mechanisms are not completely defined. OBJECTIVE: We have investigated the effects of desloratadine and loratadine on rhinovirus-induced ICAM-1 expression, mRNA upregulation, and promoter activation. METHODS: Cultured primary bronchial or transformed (A549) respiratory epithelial cells were pretreated with desloratadine and loratadine for 16 hours and infected with rhinovirus type 16 for 8 hours. ICAM-1 surface expression was evaluated with flow cytometry, and ICAM-1 mRNA was evaluated with specific RT-PCR. In A549 cells promoter activation was evaluated with a chloramphenicol acetyltransferase assay, and binding activity of nuclear factor kappa B in nuclear extracts was evaluated with an electrophoretic mobility shift assay. RESULTS: Desloratadine and loratadine (0.1-10 micromol/L) inhibited rhinovirus-induced ICAM-1 upregulation in both primary bronchial or transformed (A549) respiratory epithelial cells. In A549 cells the 2 compounds showed a dose-dependent inhibition with similar efficacy (inhibitory concentration of 50%, 1 micromol/L). Desloratadine and loratadine also inhibited ICAM-1 mRNA induction caused by rhinovirus infection in a dose-dependent manner, and they completely inhibited rhinovirus-induced ICAM-1 promoter activation. Desloratadine also inhibited rhinovirus-induced nuclear factor kappa B activation. Desloratadine and loratadine had no direct effect on rhinovirus infectivity and replication in cultured epithelial cells. CONCLUSION: These effects are unlikely to be mediated by H(1)-receptor antagonism and suggest a novel mechanism of action that may be important for the therapeutic control of virus-induced asthma exacerbations.     

Modulation of endothelin-1 expression in pulmonary epithelial cell line (A549) after exposure to RSV

Respiratory syncytial virus (RSV) is one of the most important respiratory tract pathogens in infants and young children. The airway epithelial cells are the primary target cells for RSV infection. The airway epithelial layer is not only a physical barrier, but also plays a role in a synthesis of a variety of major inflammatory cytokines (IL-6, IL-8, GM-CSF etc.) as previously reported. Endothelin-1 (ET-1) is a potent bronchoconstrictor and vasoconstrictor factor, and involved in pathogenesis of various diseases of the respiratory tract. We hypothesized that RSV may induce the release of ET-1 from the bronchial epithelial cell line. No previous data is available regarding association between RSV infection and ET-1 release. We evaluated the effect of RSV with different concentrations of RSV (MOI 0.1, 1 and 3 pfu/cell) on bronchial epithelial cell line (A549) and measured the production of ET-1 at both protein and mRNA level. A549 cells were treated with different conditions by using LPS, heat-inactivated RSV, RSV or medium alone as control. We observed time-dependent ET-1 release by RSV-infected A549 cells at 4 h, 24 h and maximum at 72 h. ET-1 was expressed in unstimulated A549 cells and was further increased by RSV. RSV with concentration MOI 0.1 (pfu/cell) and LPS appeared to have strongest stimulation on production of ET-1. In addition, ET-1 mRNA was increased significantly by 16 h and decreased to relatively low-level at 24 h. These experiments suggested that airway epithelial cells might play a role in the local airway smooth muscle tone through the production of endothelin-1 during RSV infection.     

Interleukin-8, interleukin-6, and soluble tumour necrosis factor receptor type I release from a human pulmonary epithelial cell line (A549) exposed to respiratory syncytial virus.

The release of interleukin-8 (IL-8), interleukin-6 (IL-6) and the soluble forms of the tumour necrosis factor receptor (sTNF-R) from human pulmonary type II-like epithelial cells (A549) after respiratory syncytial virus (RSV) infection was analysed. RSV infection alone induced a time- and RSV dose-dependent IL-8 and IL-6 release from A549 cells. Furthermore, the soluble form of the TNF-RI was also secreted in a time- and RSV dose-dependent fashion. The soluble TNF-RII was not detected in the cell supernatant of infected epithelial cells. The effect of various cytokines [IL-1 alpha/beta, TNF-alpha/beta, IL-3, IL-6, interferon-gamma (IFN-gamma), transforming growth factor-beta 2 (TGF-beta 2)] and colony-stimulating factors [granulocyte (G)-CSF; granulocyte-macrophage (GM)-CSF] on the IL-8 release from A549 cells was also studied. Our data show that the proinflammatory cytokines IL-1 alpha/beta and TNF-alpha/beta induced an IL-8 release in non-infected A549 cells, and increased the IL-8 release of RSV-infected A549 cells synergistically. In addition, IL-3, G-CSF, IFN-gamma and TGF-beta 2, albeit at high concentrations, induced a low IL-8 release from non-infected A549 cells. The enhanced IL-8 secretion rates were accompanied with elevated cytoplasmic IL-8 mRNA steady state levels, as was shown by Northern blot analysis. Cellular co-culture experiments performed with A549 cells and polymorphonuclear granulocytes or peripheral blood mononuclear cells revealed that increased IL-8 amounts were secreted in the co-culture of non-infected as well as RSV-infected cells. The present study suggests a central role for the airway epithelium during RSV infection with regard to cytokine and cytokine receptor release, resulting in a recruitment and activation of inflammatory and immune effector cells. Our data also suggest that paracrine cytokine networks and cell-cell contact are involved in the regulation of IL-8 secretion within the microenvironment of the bronchial epithelium.     

Molecular mechanisms of lipopolysaccharide induced ICAM-1 expression in A549 cells

OBJECTIVE AND DESIGN: Lung intercellular adhesion molecule-1 (ICAM-1) expression is increased by LPS or hyperoxia on type II cells in vivo. The goals of the present study were to determine the mechanisms of ICAM-1 expression in a lung alveolar epithelial cell line (A549) exposed to lipopolysaccharide (LPS). MATERIALS: A549 cells, a transformed human cell line with characteristics of alveolar epithelial cells, were used. TREATMENT: Cells were exposed to LPS, TNF-alpha, IL-1beta, or media alone for up to 12 h. METHODS: Northern blot analyses were done to determine mRNA expression of ICAM-1 after exposures. Protein binding to NF-kappaB sequences were determined by gel mobility shift assays and super-shift analysis. RESULTS: ICAM-1 mRNA expression was induced in A549 cells with exposure to LPS for 1 to 4 h, and was diminished to baseline at 8 h, and the inductions were independent of TNF-alpha and IL-1beta expression. Nuclear protein extracts from LPS-exposed cells bound to a NF-kappaB sequence and the timing of increased binding correlated closely with ICAM-1 mRNA induction. Super-shift studies indicated that p65 was involved in the binding to the NF-kappaB sequence and p50 was not. CONCLUSION: LPS inducibility of ICAM-1 mRNA in A549 cells is independent of TNF- and IL-1 in A549 cells, and the similar time course of mRNA induction and NF-kappaB activation suggest the induction of ICAM-1 is mediated, in part, by NF-kappaB.     

Respiratory syncytial virus stimulation of vascular endothelial cell growth Factor/Vascular permeability factor

We hypothesized that respiratory syncytial virus (RSV)-induced pathologies could be mediated, in part, by vascular active cytokines elaborated during virus infection. To address this hypothesis, we determined whether RSV stimulated vascular endothelial cell growth factor (VEGF)/vascular permeability factor (VPF) elaboration in vitro. Supernatants from unstimulated A549 cells and normal human bronchial epithelial cells contained modest levels of VEGF. In contrast, supernatants from RSV-infected cells contained elevated levels of VEGF/VPF. This stimulation was seen after as little as 2 h, was still prominent after 48 h, and, by immunoblot, was specific for the 165- and 121-amino acid isoforms of VEGF/VPF. It was not associated with significant cell cytotoxicity or alterations in VEGF messenger RNA. It did, however, require new protein biosynthesis. In accordance with these findings, the 165- and 121-amino acid isoforms of VEGF/VPF were also found in the nasal washings from patients with RSV infections. These studies demonstrate that RSV is a potent stimulator of VEGF/VPF elaboration and that, in vitro, this stimulation is mediated via a noncytotoxic translational and/or post-translational biosynthetic mechanism. VEGF/VPF may play an important role in the pathogenesis of RSV-induced disorders.     

呼吸道合胞病毒对人支气管上皮细胞通透性的影响

目的探讨呼吸道合胞病毒对支气管上皮细胞通透性的影响。方法通过ELISA、荧光定量PCR检测呼吸道合胞病毒感染人支气管上皮细胞后对其血管内皮生长因子（VEGF）表达的影响,同时,通过检测细胞的跨膜电阻了解呼吸道合胞病毒对人支气管上皮细胞通透性的影响。结果呼吸道合胞病毒增加了人支气管上皮细胞VEGF的表达,增加了支气管上皮细胞的通透性,VEGF的单克隆抗体可以明显阻断这一效应。结论呼吸道合胞病毒通过上调VEGF的表达增加对支气管上皮细胞的通透性。     

Role of the lipoxygenase pathway in RSV-induced alternatively activated macrophages leading to resolution of lung pathology

Resolution of severe Respiratory Syncytial Virus (RSV)-induced bronchiolitis is mediated by alternatively activated macrophages (AA-Mφ) that counteract cyclooxygenase (COX)-2-induced lung pathology. Herein, we report that RSV infection of 5-lipoxygenase (LO)^−/− and 15-LO^−/− macrophages or mice failed to elicit AA-Mφ differentiation and concomitantly exhibited increased COX-2 expression. Further, RSV infection of 5-LO^−/− mice resulted in enhanced lung pathology. Pharmacologic inhibition of 5-LO or 15-LO also blocked differentiation of RSV-induced AA-Mφ in vitro and, conversely, treatment of 5-LO^−/− macrophages with downstream products, lipoxin A₄ and resolvin E1, but not leukotriene B₄ or leukotriene D₄, partially restored expression of AA-Mφ markers. Indomethacin blockade of COX activity in RSV-infected macrophages increased 5-LO and 15-LO, as well as arginase-1 mRNA expression. Treatment of RSV-infected mice with indomethacin also resulted not only in enhanced lung arginase-1 mRNA expression and decreased COX-2, but also decreased lung pathology in RSV-infected 5-LO^−/− mice. Treatment of RSV-infected cotton rats with a COX-2-specific inhibitor resulted in enhanced lung 5-LO mRNA and AA-Mφ marker expression. Together, these data suggest a novel therapeutic approach for RSV that promotes AA-Mφ differentiation by activating the 5-LO pathway.     

The non-proteolytic house dust mite allergen Der p 2 induce NF-κB and MAPK dependent activation of bronchial epithelial cells

Background House dust mites (HDM) are well‐known as a source of indoor aeroallergens and for causing allergic airway diseases. Some proteolytic HDM allergens are known to activate respiratory epithelial cells to produce pro‐inflammatory mediators, while there is limited knowledge regarding such activity among non‐proteolytic HDM allergens. Objective To investigate whether Der p 2, a major non‐proteolytic allergen of Dermatophagoides pteronyssinus, activates respiratory epithelial cells to produce mediators involved in asthma pathogenesis and to elucidate the mechanism of such activation. Methods The human bronchial epithelial cell line BEAS‐2B, normal human bronchial epithelial (NHBE) cells and the alveolar epithelial cell line A549 were exposed to recombinant Der p 2. Following exposure, we analysed a panel of soluble mediators and cell adhesion receptors involved in asthma pathogenesis by promoting recruitment, survival and binding of inflammatory cells. The involvement of nuclear factor (NF)‐κB and mitogen‐activated protein kinases (MAPKs) was studied using specific inhibitors. Results Der p 2 activated bronchial BEAS‐2B and NHBE cells, but not alveolar A549 cells. In BEAS‐2B cells Der p 2 induced dose‐dependent up‐regulation in both mRNA level and protein secretion of granulocyte‐macrophage colony‐stimulating factor, IL‐6, IL‐8, monocyte‐chemotactic protein‐1 and macrophage inflammatory protein‐3α. Secretion as well as surface expression of intercellular adhesion molecule (ICAM)‐1 was also up‐regulated, which was associated with increased adhesion of monocytes to the epithelial cells. The release of cytokines and chemokines was regulated by NF‐κB and MAPK activation in different ways, while expression of ICAM‐1 was solely dependent on NF‐κB activation. Conclusion These results show that Der p 2 activates respiratory epithelial cells, indicating that this non‐proteolytic allergen, in addition to its immunogenic properties, can aggravate respiratory airway disease by adjuvant‐like activation of the lung epithelium.