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Beside the production of complete immunoglobulins IgG, IgE, IgA, IgM and IgD, consisting of tetrameric heterodimers of immunoglobulin heavy and light chains, B cells also secrete immunoglobulin free light chains (Ig-fLC). Previous studies showed that Ig-fLCs are able to induce immediate hypersensitivity reactions. It is apparent that recognition and binding of antigen are crucial steps in the onset of these inflammatory responses. In this study, the binding characteristics of Ig-fLC to antigen were further investigated using various biochemical approaches. In addition, we investigated whether antigen-mediated crosslinking of Ig-fLC is required to initiate allergic skin inflammation in vivo. Our study shows that binding of Ig-fLCs to antigen can be measured with different experimental setups. Surface plasmon resonance analysis showed real-time antigen binding characteristics. Specific antigen binding by Ig-fLCs was further detected using immunoblotting and ELISA. Using the ELISA-based assay, a binding affinity of 76.9±3.8 nM was determined for TNP-specific Ig-fLC. Antigen-induced ear swelling in mice passively sensitized with trinitrophenol-specific Ig-fLC was inhibited when multivalent antigen was combined with excess of monovalent antigen during challenge. We conclude that Ig-fLCs are able to interact with antigen, a prerequisite for antigen-specific cellular activation. In analogy to antigen-specific Fc receptor-induced mast cell activation, crosslinking of Ig-fLCs is necessary to initiate a local allergic response.

Unlabelled: Tobacco smoke is the main factor in the etiology of lung emphysema. Generally prolonged, substantial exposure is required to develop the disease. Humic acid is a major component of cigarette smoke that accumulates in smokers' lungs over time and induces tissue damage., Objectives: To investigate whether humic acid pre-loading potentiates the development of cigarette smoke-induced lung emphysema in mice and increases IL-8 release by human monocytes., Methods: C57BL/6J mice received humic acid or aqueous vehicle by tracheal installation on day 0 and day 7. From day 21 to day 84, the mice were exposed to cigarette smoke or clean air for 5 days/week. Twenty-four hours after the last exposure we determined leukocytes in lung lavage, heart hypertrophy and alveolar wall destruction. Human monocytes were incubated with cigarette smoke extract (CSE), humic acid or the combination overnight., Results: Humic acid nor cigarette smoke caused alveolar wall destruction within two months. Interestingly, the combination did induce lung emphysema. Humic acid, cigarette smoke or the combination did not change leukocyte types and numbers in lung lavage fluid, but the combination caused peribronchiolar and perivascular lymphocyte infiltration. Humic acid treatment resulted in a high proportion of alveolar macrophages heavily loaded with intracellular granula. Humic acid also induces the release of IL-8 from human monocytes and enhances the CSE-induced IL-8 release., Conclusions: Humic acid deposition in the lungs potentiates the development of cigarette smoke-induced interstitial inflammation and lung emphysema. Moreover, humic acid promotes IL-8 release from human monocytes. Since humic acid accumulates steadily in the lungs of smokers, this may provide an explanation for the natural history on late onset of this disease. The model described here offers a novel way to study emphysema and may direct the search for new therapeutic approaches., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Chronic inflammation in lung diseases contributes to lung tissue destruction leading to the formation of chemotactic collagen fragments such as N-acetylated Proline-Glycine-Proline (N-ac-PGP). In this study, we investigated in more detail the mechanism of action of N-ac-PGP in neutrophilic inflammation. N-ac-PGP was chemotactic for human neutrophils via pertussis toxin sensitive G protein-coupled receptors in vitro and directly activated this cell type, which led to cytosolic calcium mobilization and release of CXCL8. Furthermore, using a selective CXCR2 antagonist confirmed that N-ac-PGP-induced neutrophil chemotaxis is mediated through CXCR2 activation. To determine whether N-ac-PGP was solely responsible for the migration and activation of human neutrophils in vitro and not the released CXCL8 upon stimulation with N-ac-PGP, an antibody directed against CXCL8 was used. Performing chemotaxis and calcium influx assays in the presence of this antibody did not alter the effects of N-ac-PGP whereas effects of CXCL8 were attenuated. These experiments indicate that N-ac-PGP, in addition to the direct induction of chemotaxis, also directly activates neutrophils to release CXCL8. In vivo, this may lead in the long term to a self-maintaining situation enhanced by both N-ac-PGP and CXCL8, leading to a further increase in neutrophil infiltration and chronic inflammation., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Chronic obstructive pulmonary disease (COPD) is characterized by chronic airway inflammation. Cigarette smoke has been considered a major player in the pathogenesis of COPD. The inflamed airways of COPD patients contain several inflammatory cells. Vitamin A metabolites have been implicated in the repair of lung damage. Exposure to cigarette smoke has been shown to depress levels of retinol in lungs of rats. The purpose of this study was to investigate if a low, but not deficient, vitamin A status potentiated susceptibility to the development of cigarette smoke-induced lung emphysema in mice. Mice were bred that were the offspring's of 3 generations of mice that were fed a purified diet containing low levels of vitamin A and exposed to cigarette smoke for 3 months, every weekday. Then, levels of 9-cis, 13-cis, and all-trans retinoic acid, retinol and retinyl palmitate were measured in plasma, liver and right lung lobe. The left lung lobe was used to assess mean linear intercept (Lm), as a measure of smoke-induced lung damage. Average feed intakes were not different between treatment groups. We show that both retinol and retinyl palmitate levels were dramatically decreased in the storage organs of mice on the low vitamin A diet (retinol 2-fold in both lung and liver, and retinyl palmitate 5- fold in lung) which shows that the depletion was successful. However, this treatment did not result in the development of lung emphysema. However, smoke exposure led to a significant increase in Lm in mice with a low vitamin A status compared to the room air-breathing controls. Lung levels of acid retinoids were similar in all mice, irrespective of diet or smoke exposure. Concluding, a low vitamin A status increases the susceptibility to the development of cigarette smoke-induced lung emphysema, possibly because of decreased anti-oxidant capacity in the lungs due to locally reduced retinol and retinyl palmitate levels. These observations indicate that human populations with a low vitamin A status and a high prevalence of smoking may be at increased risk of developing lung emphysema.

There is increasing evidence that the neutrophil chemoattractant proline-glycine-proline (PGP), derived from the breakdown of the extracellular matrix, plays an important role in neutrophil recruitment to the lung. PGP formation is a multistep process involving neutrophils, metalloproteinases (MMPs), and prolyl endopeptidase (PE). This cascade of events is now investigated in the development of lung emphysema. A/J mice were whole body exposed to cigarette smoke for 20 wk. After 20 wk or 8 wk after smoking cessation, animals were killed, and bronchoalveolar lavage fluid and lung tissue were collected to analyze the neutrophilic airway inflammation, the MMP-8 and MMP-9 levels, the PE activity, and the PGP levels. Lung tissue degradation was assessed by measuring the mean linear intercept. Additionally, we investigated the effect of the peptide L-arginine-threonine-arginine (RTR), which binds to PGP sequences, on the smoke-induced neutrophil influx in the lung after 5 days of smoke exposure. Neutrophilic airway inflammation was induced by cigarette smoke exposure. MMP-8 and MMP-9 levels, PE activity, and PGP levels were elevated in the lungs of cigarette smoke-exposed mice. PE was highly expressed in epithelial and inflammatory cells (macrophages and neutrophils) in lung tissue of cigarette smoke-exposed mice. After smoking cessation, the neutrophil influx, the MMP-8 and MMP-9 levels, the PE activity, and the PGP levels were decreased or reduced to normal levels. Moreover, RTR inhibited the smoke-induced neutrophil influx in the lung after 5 days' smoke exposure. In the present murine model of cigarette smoke-induced lung emphysema, it is demonstrated for the first time that all relevant components (neutrophils, MMP-8, MMP-9, PE) involved in PGP formation from collagen are upregulated in the airways. Together with MMPs, PE may play an important role in the formation of PGP and thus in the pathophysiology of lung emphysema.

Chronic obstructive pulmonary disease (COPD) is a major health problem and cigarette smoke is the main risk factor for the development of COPD. The characteristic changes in airway morphology, inflammatory cell infiltration and mediator expression in COPD may result from direct effects of cigarette smoke on airway cells. Toll-like receptors (TLRs) are key elements in pathogen recognition by the host immune system. Although TLRs have been intensely studied in innate immunity and infection, their critical role in noninfectious challenges has only recently emerged. Here we investigate whether cigarette smoke induces TLR9 signalling in human neutrophils. Human neutrophils were isolated from buffy coat and exposed to cigarette smoke extract. The production of CXC chemokine ligand (CXCL)8 was measured as a functional readout and the role of TLR9 signalling was investigated. Cigarette smoke extract induced CXCL8 release via TLR9 activation in neutrophils, which was confirmed in TLR9 stably transfected human embryonic kidney 293 cells. Moreover, cigarette smoke extract upregulated the expression of TLR9 and the upregulated expression was suppressed by N-acetylcysteine. TLR9 mediates cigarette smoke-induced release of CXCL8 and this may contribute to the accumulation of neutrophils and inflammation within the airways of smokers.

Extracellular ATP is a signalling molecule that often serves as a danger signal to alert the immune system of tissue damage. This molecule activates P2 nucleotide receptors, that include the ionotropic P2X receptors and the metabotropic P2Y receptors. Several publications highlight the importance of purinergic signalling in the pathogenesis of chronic airway inflammation. Recently, it has been reported that ATP accumulates in the airways of both animal models and patients with asthma or chronic obstructive pulmonary diseases (COPD); however, the role and function of ATP in the diseases process of COPD are not well understood. In this perspective, a brief overview is given on the role of ATP and P2 receptors in the pathogenesis of lung emphysema and COPD with a focus on neutrophils as messengers in intercellular communication between epithelial cells and macrophages and the activation of inflammasome pathways. Finding the link between purinergic signalling with inflammasome pathways will be a challenge for the future and could lead to the discovery of new therapeutic drugs for suppressing inflammation in the lungs of COPD patients., ((c) 2010 Elsevier B.V. All rights reserved.)

Background: Tobacco smoking irritates and damages the respiratory tract and contributes to a higher risk of developing lung emphysema. At present, smoking cessation is the only effective treatment for reducing the progression of lung emphysema, however, there is hardly anything known about the effects of smoking cessation on cytokine and chemokine levels in the airways. To the best of our knowledge, this is the first reported in vivo study in which cytokine profiles were determined after cessation of cigarette smoke exposure., Methods: The severity of airway remodeling and inflammation was studied by analyzing alveolar enlargement, heart hypertrophy, inflammatory cells in the bronchoalveolar lavage fluid (BALF) and lung tissue and by determining the cytokine and chemokine profiles in the BALF of A/J mice exposed to cigarette smoke for 20 weeks and 8 weeks after smoking cessation., Results: The alveolar enlargement and right ventricle heart hypertrophy found in smoke-exposed mice remained unchanged after smoking cessation. Although the neutrophilic inflammation in the BALF of cigarette smoke-exposed animals was reduced after smoking cessation, a sustained inflammation in the lung tissue was observed. The elevated cytokine (IL-1 alpha and TNF-alpha) and chemokine (CCL2 and CCL3) levels in the BALF of smoke-exposed mice returned to basal levels after smoking cessation, while the increased IL-12 levels did not return to its basal level. The cigarette smoke-enhanced VEGF levels did not significantly change after smoking cessation. Moreover, IL-10 levels were reduced in the BALF of smoke-exposed mice and these levels were still significantly decreased after smoking cessation compared to the control animals., Conclusion: The inflammatory changes in the airways caused by cigarette smoke exposure were only partially reversed after smoking cessation. Although smoking cessation should be the first step in reducing the progression of lung emphysema, additional medication could be provided to tackle the sustained airway inflammation.

Traditionally, mast cells were regarded as key cells orchestrating type I hypersensitivity responses. However, it is now recognized that mast cells are widely involved in nonallergic (non-IgE) chronic diseases. Also, in inflammatory bowel disease (IBD), a disease not associated with increased IgE concentrations, clear signs of activation of mast cells have been found. In this study, we investigated if Ig-free L chain-induced hypersensitivity-like responses through activation of mast cells could contribute to the pathophysiology of IBD. As a mast cell-dependent model for IBD, mice were skin-sensitized with dinitrofluorobenzene followed by intrarectal application of the hapten. In this murine IBD model, F991 prevented mast cell activation and also abrogated the development of diarrhea, cellular infiltration, and colonic lymphoid follicle hyperplasia. Furthermore, passive immunization with Ag-specific Ig-free L chains (IgLCs) and subsequent rectal hapten challenge elicited local mast cell activation and increased vascular permeability in the colon of mice. Clinical support is provided by the observation that serum concentrations of IgLCs of patients suffering from Crohn's disease are greatly increased. Moreover, increased presence of IgLCs was evident in tissue specimens from colon and ileum tissue of patients with IBD. Our data suggest that IgLCs may play a role in the pathogenesis of IBD, which provides novel therapeutic means to prevent or ameliorate the adverse gastrointestinal manifestations of IBD.

Hypoallergenic milk formulae are used for cow's milk allergic infants and may be a good option for infants at risk. Clinical studies have shown that the protein source or the hydrolysis methodology used may influence the effectiveness in infants stressing the importance of adequate pre-clinical testing of hypoallergenic formulae in an in vivo model of orally induced cow's milk allergy. This study was undertaken to introduce a new read-out system to measure the residual allergenicity of whey hydrolysates on both the sensitization and challenge phase of orally induced cow's milk allergy in mice. Mice were sensitized orally to whey or a partial whey hydrolysate (pWH) to measure the residual sensitizing capacity. To predict the residual allergenicity of hydrolysates, whey allergic mice were challenged in the ear with pWH, extensive whey hydrolysate or an amino acid-based formula. An acute allergic skin response (ear swelling at 1 h), whey-specific serum antibodies, and local MCP-1 concentrations were measured. In contrast to whey, oral sensitization with pWH did not result in the induction of whey-specific antibodies, although a minor residual skin response to whey was observed after challenge. Skin exposure to whey hydrolysates showed a hydrolysation dependent reduction of the acute allergic skin response in whey allergic mice. In contrast to whey, skin exposure to pWH did not enhance tissue MCP-1 levels. The acute allergic skin response in mice orally sensitized to cow's milk proteins reveals a new pre-clinical tool which might provide information about the residual sensitizing capacity of hydrolysates supporting the discussion on the use of hypoallergenic formulae in high risk children. This mouse model might be a relevant model for the screening of new hypoallergenic formulae aimed to prevent or treat cow's milk allergy.

Macrophages are key inflammatory cells in chronic obstructive pulmonary disease (COPD). The pathophysiology of cigarette smoke-induced lung emphysema is complex but there is a clear role for reactive oxygen species (ROS, such as peroxynitrite), tumor necrosis factor (TNF-alpha) and interleukin (IL)-8. We investigated whether TNF-alpha or cigarette smoke medium (CSM) alone or in combination induces the production of IL-8 by human macrophages or monocyte lymphoma U937. CSM and TNF-alpha induce a dose- and time-dependent increase in IL-8 production. Interestingly, when sub-threshold concentrations of CSM and TNF-alpha were co-incubated, a 1500% increase in IL-8 production was observed compared to either of the compounds alone. Similar results were obtained with TNF-alpha and the peroxynitrite donor SIN-1. Moreover, the overproduction of IL-8 was associated with an enhanced increase in the translocation of NF-kappaB and an enhanced decrease in glutathione levels. Preincubation of the cells with antioxidants, such as N-acetyl-L-cysteine (NAC), prevented the overproduction of IL-8 and activation of NF-kappaB. In conclusion, CSM exposure of macrophages up-regulates the expression and the production of IL-8 via reactive oxygen species and NF-kappaB activation. Moreover, CSM dramatically enhances the production of IL-8 in combination with TNF-alpha. Based upon the strong synergistic action, a combination therapy directed against ROS and TNF-alpha could be a new approach to stop the progression in lung damage during emphysema., (2009 Elsevier Inc. All rights reserved.)

The prevalence of asthma has increased worldwide. The reasons for this rise remain unclear. Oxidative stress plays an important role in the pathogenesis of asthma. Glutathione (GSH) is the major representative of the class of nonprotein thiols and plays a pivotal role in a variety of enzymatic and nonenzymatic reactions that protect tissues against oxidative stress. In antioxidative reactions, GSH is converted into its oxidized form, glutathione disulfide (GSSG) that in its turn is enzymatically reduced into GSH to maintain a physiological redox balance. We used a guinea pig model of asthma to assess whether the early asthmatic reaction is associated with decreased lung levels of glutathione, and whether decreased glutathione is implicated in the increased airway smooth muscle reactivity that is associated with exposure of the lungs to allergen. Lung glutathione levels were decreased immediately after the onset of the early asthmatic reaction in vivo and associated with the release of 8-iso-PGF(2alpha), an indicator for oxidative stress. Glutathione ethylester, a glutathione precursor, blunted the airway obstruction during an early asthmatic reaction in a perfusion model and glutathione depletion rendered the airways hyperreactive. Glutathione ethyl ester in the buffer prevented this hyperreactivity. These results indicate that glutathione can modulate the early asthmatic reaction as well as the airway hyperresponsiveness.

Background/aim: Evidence demonstrating an important role of the intestinal microbiota in the incidence of allergic disorders has led to the concept of using probiotics as possible antiallergic therapy. This study aimed to select a bacterial strain with the best antiallergic treatment effects from a panel of 6 bacterial strains in a mouse model of ovalbumin(OVA)-allergic asthma., Methods: OVA-sensitized BALB/c mice were orally administered the bacterial strains Bifidobacterium breve M-16V, B. infantis NumRes251, B. animalis NumRes252 and NumRes253, Lactobacillus plantarum NumRes8 and L. rhamnosus NumRes6. After challenge by OVA inhalation in the lungs, the response to methacholine was measured. Pulmonary inflammation was assessed by analyzing bronchoalveolar lavage fluid for the presence of eosinophils, neutrophils, macrophages and lymphocytes and for interleukin 4, interleukin 5, interleukin 10 and interferon-gamma. OVA-specific IgE, IgG1 and IgG2a were measured in serum. Next, the effect on acute allergic skin reaction was measured after treatment with B. breve M-16V and L. plantarum NumRes8., Results: Of the panel of 6 strains, B. breve M-16V and L. plantarum NumRes8 inhibited (1) the response to methacholine, (2) reduced the number of eosinophils in the bronchoalveolar lavage fluid, (3) reduced both OVA-specific IgE and (4) OVA-specific IgG1, whereas the other strains did not affect all these parameters simultaneously. B. breve M-16V but not L. plantarum NumRes8 reduced interleukin 4, interleukin 5 and interleukin 10. Furthermore, B. breve M-16V but not L. plantarum NumRes8 reduced acute allergic skin reactions to OVA., Conclusion: B. breve M-16V was identified as the most potent antiallergic strain., (2009 S. Karger AG, Basel.)

Extracellular ATP is a signaling molecule that often serves as a danger signal to alert the immune system of tissue damage. This molecule activates P2 nucleotide receptors, that include the ionotropic P2X receptors and metabotropic P2Y receptors. Recently, it has been reported that ATP accumulates in the airways of both asthmatic patients and sensitized mice after allergen challenge. The role and function of ATP in the pathogenesis of chronic obstructive pulmonary diseases (COPD) are not well understood. In this study we investigated the effect of cigarette smoke on purinergic receptors and ATP release by neutrophils. Neutrophils and their mediators are key players in the pathogenesis of lung emphysema. Here we demonstrated that in an in vivo model of cigarette smoke-induced lung emphysema, the amount of ATP was increased in the bronchoalveolar lavage fluid. Moreover, activation of neutrophils with cigarette smoke extract induced ATP release. Treatment of neutrophils with apyrase (catalyses the hydrolysis of ATP to yield AMP) and suramin (P2-receptor antagonist) abrogated the release of CXCL8 and elastase induced by cigarette smoke extract and exogenous ATP. These observations indicate that activation of purinergic signaling by cigarette smoke may take part in the pathogenesis of lung emphysema.

Myeloid and plasmacytoid dendritic cells (mDCs, pDC) are crucial to the immune system, detecting microorganisms and linking the innate and adaptive immunity. pDC are present in small quantities in tissues that are in contact with the external environment; mainly the skin, the inner lining of the nose, lungs, stomach and intestines. They produce large amounts of IFN-alpha after stimulation and are pivotal for the induction of antiviral responses. Chronic obstructive pulmonary disease (COPD) patients are known to be more susceptible to viral infections. We have demonstrated that exposure of mDC to cigarette smoke extract (CSE) leads to the release of chemokines, however, not much is known about the role of pDC in COPD. In this study, we addressed several key questions with respect to the mechanism of action of CSE on human pDC in an in vitro model. Human pDCs were isolated from normal healthy volunteers and subjected to fresh CSE and the levels of IL-8, TNF-alpha, IP-10, IL-6, IL-1, IL-12 and IL-10 and IFN-alpha were studied by both ELISA and real time PCR methods. We observed that CSE augmented the production of IL-8 and suppressed the release of TNF-alpha, IL-6 and IFN-alpha. Moreover, CSE suppressed PI3K/Akt signalling in pDC. In conclusion, our data indicate that CSE has both the potential to diminish anti-viral immunity by downregulating the release of IFN-alpha and other pro-inflammatory cytokines while, at the same time, augmenting the pathogenesis of COPD via an IL-8 induced recruitment of neutrophils.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are major drugs used in the treatment of inflammation and pain in a wide variety of disorders. The best-known mechanism of action of NSAIDs is the inhibition of prostaglandin synthesis as a result of their action on cyclooxygenase (COX) enzymes. However, data have been accumulating through the years indicating that NSAIDs also act on other targets in cell signaling. It has been established that NSAIDs induce anti-inflammatory effects independent of COX. Acetylsalicylic acid (ASA) and other inhibitors of COX induce severe bronchospasms and asthmatic attacks in a significant population of asthmatic patients. The etiology of ASA induced asthma is complex and not fully understood, but most evidence points towards an abnormality of arachidonic acid (AA) metabolism. Since doses of ASA necessary to treat chronic inflammatory diseases appeared much higher than those required to inhibit PG synthesis, COX-independent mechanisms of NSAIDs were postulated. Recently, we have shown that NSAIDs induced expression of heat shock proteins specially HSP70. Heat shock proteins (HSPs) are normal intracellular proteins that are produced in greater amounts when cells are subjected to stress or injury. Interestingly, a potential pathogenic role for heat shock proteins in diseases such as autoimmune disease, vascular disease has been reported. Because mast cells have been reported to play a role in the pathogenesis of ASA induced asthma, a link between heat shock proteins and this disease could postulated. In this review, an overview is given on aspirin-induced asthma and the cells and mediators that may play a role therein. Mast cell signaling with regard to interaction with NSAIDs and heat shock proteins (HSPs) and toll-like receptors (TLRs) is further highlighted.

Background: Mast cells are important effector cells in innate or acquired immunity that contribute to host defence. Excessive activation of mast cells can result in the development of allergic diseases, including atopic asthma. Mast cell activation by IgE and specific antigen induces the cells to release spasmogenic, vasoactive and pro-inflammatory mediators, which enhance airway smooth muscle contraction, vascular permeability and inflammatory cell recruitment. Recently, we have demonstrated that exposure of mast cells to cigarette smoke medium (CSM) triggered mast cells to produce chemokines. On the other hand, smoking may decrease the risk of allergic sensitization, which could be explained by a reduced IgE production or a diminished response of mast cells to activation of the IgE receptor., Objective: In this study, we investigated the effect of CSM on the allergic activation of mast cells through IgE and antigen., Methods: Primary cultured murine mast cells were exposed to CSM and activated with IgE and antigen or lipopolysaccharide (LPS). The release of granules, production of leukotrienes, chemokines and cytokines was determined in the supernatants by ELISA. The effect of CSM exposure on intracellular signalling, especially the nuclear factor (NF)-kappaB and extracellular signal-regulated kinase (Erk)1/2 pathways, was analysed by Western blotting., Results: CSM suppressed IgE-mediated degranulation and cytokine release, but no effect was observed on leukotriene release. CSM induced phosphorylation of Erk1/2 in mast cells. In CSM-exposed mast cells, activating transcription factor (ATF)-1 was phosphorylated after stimulation with IgE/Ag. LPS-activated mast cells were not influenced by CSM., Conclusion: Our study suggests that exposure to cigarette smoke may lead to a reduced allergic activation of mast cells without affecting their response to activation via e.g. bacterial-derived LPS.

Background: Toll-like receptors (TLRs) are present on monocytes and alveolar macrophages that form the first line of defense against inhaled particles. The importance of those cells in the pathophysiology of chronic obstructive pulmonary disease (COPD) has well been documented. Cigarette smoke contains high concentration of oxidants which can stimulate immune cells to produce reactive oxygen species, cytokines and chemokines., Methods: In this study, we evaluated the effects of cigarette smoke medium (CSM) on TLR4 expression and interleukin (IL)-8 production by human macrophages investigating the involvement of ROS., Results and Discussion: TLR4 surface expression was downregulated on short term exposure (1 h) of CSM. The downregulation could be explained by internalization of the TLR4 and the upregulation by an increase in TLR4 mRNA. IL-8 mRNA and protein were also increased by CSM. CSM stimulation increased intracellular ROS-production and decreased glutathione (GSH) levels. The modulation of TLR4 mRNA and surface receptors expression, IRAK activation, IkappaB-alpha degradation, IL-8 mRNA and protein, GSH depletion and ROS production were all prevented by antioxidants such as N-acetyl-L-cysteine (NAC)., Conclusion: TLR4 may be involved in the pathogenesis of lung emphysema and oxidative stress and seems to be a crucial contributor in lung inflammation.

Immunoglobulin-free light chains (IgLC) secreted by B lymphocytes, have been shown to mediate hypersensitivity by inducing antigen-specific mast cell activation. Although both mast cells and sensory neurons contribute to the hypersensitivity response, the role of IgLC in relation to sensory neurons is unknown. We therefore aimed to investigate the effects of IgLC on cultures of murine dorsal root ganglion (DRG) neurons. Immunohistochemistry demonstrated that IgLC and IgE could specifically bind to DRG neurons, on which the presence of FcepsilonRI, the specific receptor for IgE, was demonstrated by western blotting. Further, optical recordings with Fluo-4 showed that application of the corresponding antigen to IgLC- or IgE-sensitized DRG neurons induces a sustained increase in intracellular Ca(2+) in about half of these neurons. These results show that IgLC and IgE can mediate antigen-specific responses in murine neurons. Our findings present a novel way of antigen-specific neuronal activation.

Allergic diseases have become a serious global health problem in the developed world. IgE interacting with its high-affinitiy receptor FcepsilonRI is considered a major contributing factor to most types of allergies, but depending on the type of allergy, however, a subgroup of patients displays common symptoms and yet lack elevated levels of total serum IgE and/or antigen-specific IgE. Novel therapeutic strategies such as anti-IgE therapy may therefore not be applicable to these patients. It is clear, however, that these patients do display activation of mast cells. In several patients suffering from immunological disorders, an increase in free immunoglobulin (IG) light chain levels can be detected. Previously, we have described the capability of free light chains to elicit immediate hypersensitivity responses. In this Opinion article, we will discuss the role of IgE- and non-IgE-mediated mechanisms in allergic disorders and point out a possible role of free IG light chains in the pathogenesis of the non-atopic types of these allergies.

Chronic obstructive pulmonary disease (COPD) is characterized by chronic airway inflammation. Cigarette smoke has been considered a major player in the pathogenesis of COPD. The inflamed airways of COPD patients contain several inflammatory cells including neutrophils, macrophages,T lymphocytes, and dendritic cells (DCs). The relative contributions of these various inflammatory cells to airway injury and remodeling are not well documented. In particular, the potential role of DCs as mediators of inflammation in the smoker's airways and COPD patients is poorly understood. In the current study we analyzed the effects of cigarette smoke extract on mouse bone marrow derived DC and the production of chemokines and cytokines were studied. In addition, we assessed CSE-induced changes in cDC function in the mixed lymphocyte reaction (MLR) examining CD4+ and CD8+ T cell proliferation. Cigarette smoke extract induces the release of the chemokines CCL3 and CXCL2 (but not cytokines), via the generation of reactive oxygen species (ROS). In a mixed-leukocyte reaction assay, cigarette smoke-primed DCs potentiate CD8(+)T cell proliferation via CCL3. In contrast, proliferation of CD4(+)T cells is suppressed via an unknown mechanism. The cigarette smoke-induced release of CCL3 and CXCL2 by DCs may contribute to the influx of CD8(+)T cells and neutrophils into the airways, respectively.

In patients with chronic obstructive pulmonary disease (COPD), an inflammatory process is ongoing in the lungs, with concomitant damage of the alveolar structures and loss of airway function. In this inflammatory process, extracellular matrix degradation is observed. During this lung matrix degradation, small peptide fragments consisting of proline and glycine repeats generated from collagen fibers are liberated from the matrix by matrix metalloproteinases. Chemotactic activities of these collagen-derived peptides such as N-acetyl-proline-glycine-proline (PGP) via CXCR1 and CXCR2 have been reported. We show here that PGP induces neutrophil migration in vivo, which is dose dependent. Moreover, PGP is involved in the development of emphysema-like changes in the airways. The complementary peptide, L-arginine-threonine-arginine (RTR), has been shown to bind to PGP sequences and inhibit neutrophil infiltration. We show that RTR impedes both PGP- and interleukin-8-induced chemotaxis in vitro. In vivo, RTR prevents both migration and activation of neutrophils induced by PGP. Furthermore, RTR completely inhibits PGP-induced lung emphysema, assessed by changes in alveolar enlargement and right ventricular hypertrophy. In conclusion, these data indicate that collagen breakdown products, especially PGP, are important in the pathogenesis of COPD and that PGP antagonism via RTR ameliorates lung emphysema.

The combination of inhaled corticosteroids and long-acting beta2-adrenoceptor agonists is increasingly used in chronic obstructive pulmonary disease (COPD). Recently, we have demonstrated that combination of salmeterol and fluticasone propionate (FP) additionally suppress the production of IL-8 by human monocyte. In this study, the molecular mechanism behind the effectiveness of this combination therapy is investigated in human neutrophils. Human neutrophils were preincubated with salmeterol or FP or the combination. The amount of interleukin-8 (IL-8), elastase and matrix metalloproteinases (MMP)-2 and -9 releases, and reactive oxygen species (ROS) generation and expression of MAP kinase phosphatase (MKP-1) and glucocorticoid receptor (GR) were determined. Cigarette smoke medium (CSM) induces an increased expression of CXC receptors and the production of ROS that may explain the strong production of IL-8 by neutrophils. The expression of CXC receptors, the production of ROS, and the release of elastase and MMP-2 and -9 were not influenced by salmeterol, FP, or the combination. Interestingly, the combination therapy had an additive suppressive effect on the CSM-induced production of IL-8. The latter could be explained by an increased mRNA expression of MKP-1, the GR and an increased translocation of the GR to the nucleus. This leads eventually to suppression of both the NF-kappaB and MAPK pathways and, hence, to less IL-8 production by the neutrophil. These data are in support for the use of a combination therapy in COPD patients.

Chronic obstructive pulmonary disease (COPD) is a global health problem. Being a progressive disease characterized by inflammation, it deteriorates pulmonary functioning. Research has focused on airway inflammation, oxidative stress, and remodelling of the airways. Macrophages, neutrophils and T cells are thought to be important key players. A number of new research topics received special attention in the last years. The combined use of inhaled corticosteroids and long-acting beta(2)-adrenoceptor agonists produces better control of symptoms and lung function than that of the use of either compound alone. Furthermore, collagen breakdown products might be involved in the recruitment and activation of inflammatory cells by which the process of airway remodelling becomes self-sustaining. Also, TLR (Toll-like receptor)-based signalling pathways seem to be involved in the pathogenesis of COPD. These new findings may lead to new therapeutic strategies to stop the process of inflammation and self-destruction in the airways of COPD patients.

The gastro-intestinal tract is well known for its largest neural network outside the central nervous system and for the most extensive immune system in the body. Research in neurogastroenterology implicates the involvement of both enteric nervous system and immune system in symptoms of inflammatory bowel disease and irritable bowel syndrome. Since both disorders are associated with increased immune cell numbers, nerve growth and activation of both immune cells and nerves, we focus in this review on the involvement of immune cell-nerve interactions in inflammatory bowel disease and irritable bowel syndrome. Firstly, the possible effects of enteric nerves, especially of the nonadrenergic and noncholinergic nerves, on the intestinal immune system and their possible role in the pathogenesis of chronic intestinal inflammatory diseases are described. Secondly, the possible effects of immunological factors, from the innate (chemokines and Toll-like receptors) as well as the adaptive (cytokines and immunoglobulins) immune system, on gastro-intestinal nerves and its potential role in the development of inflammatory bowel disease and irritable bowel syndrome are reviewed. Investigations of receptor-mediated and intracellular signal pathways in neuro-immune interactions might help to develop more effective therapeutic approaches for chronic inflammatory intestinal diseases.

Allergies are the result of an inappropriate reaction against innocuous environmental proteins. The prevalence and severity of allergic diseases has increased dramatically during the last decade in developed countries. Allergen-specific T helper (Th) cells play a pivotal role in the pathogenesis of allergic hypersensitivity reactions. These Th cells activate a complex immune reaction that triggers the release of potent mediators and enhances the recruitment of inflammatory cells, which in turn elicit an inflammatory response that leads to the clinical symptoms of allergic disease. The current therapies for allergic diseases focus primarily on control of symptoms and suppression of inflammation, without affecting the underlying cause. However, the knowledge about the pathophysiology of allergic diseases has substantially increased, offering new opportunities for therapeutic intervention. In this review, we will focus on current insights into the mechanism of allergic reactions.

Chronic respiratory inflammation is caused by a sustained influx of macrophages and neutrophils, which leads to tissue remodeling and collagen breakdown. Recently, we have identified collagen-breakdown products that can activate and attract inflammatory cells via the CXC (two cysteines with an inverting amino acid)1 and CXC2 receptors (CXCR1 and CXCR2). By using a technique called 'inverted hydropathy', small peptides were synthesized that interact specifically with the responsible collagen-breakdown products and inactivate them. After inactivation, the collagen-breakdown products are no longer able to bind to their receptors. These neutralizing peptides inhibited neutrophil influx, heart hypertrophy and lung emphysema in animal models, and they are likely to be useful in other diseases that are characterized by a chronic inflammation, such as rheumatoid arthritis and inflammatory bowel diseases, where neutrophils are potential target cells. In this opinion article we will present a new hypothesis through which the chronicity and remodeling of tissue of several inflammatory diseases could be explained.

In recent years, novel therapeutic strategies have become available for the treatment of chronic inflammatory disease. Neutralizing proinflammatory mediators such as leukotrienes and TNF-alpha, in addition to anti-IgE therapies (Omaluzimab) that target higher in the inflammatory cascade, have shown success in the treatment of allergic or autoimmune disorders. Free immunoglobulin light chains, which are produced by B lymphocytes and secreted into serum, might play a crucial role in the pathogenesis of inflammatory disease. Concentrations of free light chains are significantly increased under diverse pathological conditions in humans, and have been linked to the progression and severity of immune diseases. Here we discuss the importance of free immunoglobulin light chains as a potential therapeutic target in the treatment of chronic inflammatory disease.

Chronic obstructive pulmonary disease is a major health problem and will become the third largest cause of death in the world by 2020. It is currently believed that an exaggerated inflammatory response to inhaled irritants, in particular, cigarette smoke (CS), causes the progressive airflow limitation, in which macrophages and neutrophils are attracted by chemokines, leading to oxidative stress, emphysema, small airways fibrosis, and mucus hypersecretion. Smoking is also associated with an increase in mast cell numbers in bronchial mucosa. This study was conducted to determine the direct effects of CS on mast cell function, using murine bone marrow-derived mast cells (BMMC) as an in vitro model. BMMC were cultured from BALB/cBy mice for 3 weeks. Cells were treated with CS medium (CSM) for 30 min or 16 h. The effects of CSM on mast cell degranulation and chemokine production were measured. Moreover, we investigated the effect of CSM on IkappaB-alpha degradation and p38, Erk1/2, p65, and CREB expression by Western blotting. We found that CSM stimulated the release of chemokines in a noncytotoxic manner but did not induce mast cell degranulation. CSM induced phosphorylation of Erk1/2, p38, and CREB and increased translocation of p65 without degradation of IkappaB-alpha NF-kappaB in mast cells. The induction of chemokine production by CSM in mast cells could promote and prolong the inflammatory process. Our observations suggest that mast cells may contribute to the pathogenesis of emphysema through a direct effect of CS on the production of proinflammatory chemokines.

Background: The increase in the prevalence of allergic diseases in countries with a so-called western lifestyle may be due to a decrease in exposure to infectious agents in early life., Objective: To establish the effect of Bacille-Calmette-Guerin (BCG) vaccination in 6-week-old high-risk infants in a prospective single-blind, randomized, placebo-controlled trial on the prevalence of allergic disease at the age of 4 and 18 months., Methods: Subjects were 121 predominantly Caucasian high-risk newborns, having either a mother, or both a father and at least one sibling with past or present allergic disease. BCG or placebo was administered at the age of 6 weeks, and repeated once when both a post-vaccination scar and a positive TB skin test were absent at the age of 4 months., Results: At the age of 18 months, the prevalence of allergic disease was not significantly different between the two groups. A trend towards less eczema (P=0.07) and significantly less use of medication for eczema was shown in the BCG group compared with the placebo group (P=0.04)., Conclusion: A single (or once repeated) BCG vaccination in 6-week-old high-risk Caucasian infants was not associated with a 50% reduction in the prevalence of allergic disease. However, there could be a smaller beneficial effect of BCG, especially because a trend towards less eczema and significantly less use of medication for eczema was shown. For definite proof, a larger study should be carried out.

Specific mixtures of prebiotic oligosaccharides showed immune modulatory effects in previous murine vaccination experiments, suggesting a shift towards T-helper 1 (Th1) immunity. These mixtures consisted of short-chain galacto-oligosaccharides (scGOS) and long-chain fructo-oligosaccharides (lcFOS) in a 9:1 ratio (Immunofortis), with or without pectin-derived acidic oligosaccharides (pAOS). To investigate whether these mixtures could suppress Th2-related responses, they were tested in an ovalbumin (OVA)-induced model for experimental allergic asthma in BALB/c mice. Supplementation with two mixtures of scGOS/lcFOS and scGOS/lcFOS/pAOS at approximately 1% (w/w% net oligosaccharides) in the diet, starting two weeks before OVA sensitization and lasting until the end of the experiment, decreased of several parameters of allergic asthma. The OVA-induced airway inflammation and hyperresponsiveness was significantly suppressed by both mixtures. Moreover, OVA-specific IgE titers were decreased by more than 25%, although this effect was not significant. The effects of the oligosaccharide mixture with pAOS appeared to be more pronounced than the effects of the scGOS/lcFOS mixture without pAOS, but a direct comparison between the mixtures was not made. Overall, the results further support the hypothesis that specific mixtures of oligosaccharides modulate the Th1/Th2 balance by enhancing Th1-related and suppressing Th2-related parameters.

Background: It has been reported that Chlamydophila (C.) pneumoniae is involved in the initiation and promotion of asthma and chronic obstructive pulmonary diseases (COPD). Surprisingly, the effect of C. pneumoniae on airway function has never been investigated., Methods: In this study, mice were inoculated intranasally with C. pneumoniae (strain AR39) on day 0 and experiments were performed on day 2, 7, 14 and 21., Results: We found that from day 7, C. pneumoniae infection causes both a sustained airway hyperresponsiveness and an inflammation. Interferon-gamma (IFN-gamma) and macrophage inflammatory chemokine-2 (MIP-2) levels in bronchoalveolar lavage (BAL)-fluid were increased on all experimental days with exception of day 7 where MIP-2 concentrations dropped to control levels. In contrast, tumor necrosis factor-alpha (TNF-alpha) levels were only increased on day 7. From day 7 to 21 epithelial damage and secretory cell hypertrophy was observed. It is suggested that, the inflammatory cells/mediators, the epithelial damage and secretory cell hypertrophy contribute to initiation of airway hyperresponsiveness., Conclusion: Our study demonstrates for the first time that C. pneumoniae infection can modify bronchial responsiveness. This has clinical implications, since additional changes in airway responsiveness and inflammation-status induced by this bacterium may worsen and/or provoke breathlessness in asthma and COPD.