Lack of IL-1 Receptor Signaling Reduces Spontaneous Airway Eosinophilia in Juvenile Mice with Muco-Obstructive Lung Disease.

Previous studies demonstrated spontaneous type 2 airway inflammation with eosinophilia in juvenile Scnn1b (sodium channel, non-voltage-gated 1, ß-subunit)-transgenic (Scnn1b-Tg) mice with muco-obstructive lung disease. IL-1 receptor (IL-1R) signaling has been implicated in allergen-driven airway disease; however, its role in eosinophilic inflammation in muco-obstructive lung disease remains unknown. In this study, we examined the role of IL-1R signaling in the development of airway eosinophilia and type 2 inflammation in juvenile Scnn1b-Tg mice. We determined effects of genetic deletion of Il1r1 (IL-1 receptor type I) on eosinophil counts, transcript levels of key type 2 cytokines, markers of eosinophil activation and apoptosis, and tissue morphology in lungs of Scnn1b-Tg mice at different time points during neonatal development. Furthermore, we measured endothelial surface expression of intercellular adhesion molecule 1 (ICAM-1), an integrin involved in eosinophil transendothelial migration, and determined effects of eosinophil depletion using an anti-IL-5 antibody on lung morphology. Lack of IL-1R reduced airway eosinophilia and structural lung damage, but it did not reduce concentrations of type 2 cytokines and associated eosinophil activation in Scnn1b-Tg mice. Structural lung damage in Scnn1b-Tg mice was also reduced by eosinophil depletion. Lack of IL-1R was associated with reduced expression of ICAM-1 on lung endothelial cells and reduced eosinophil counts in lungs from Scnn1b-Tg mice. We conclude that IL-1R signaling is implicated in airway eosinophilia independent of type 2 cytokines in juvenile Scnn1b-Tg mice. Our data suggest that IL-1R signaling may be relevant in the pathogenesis of eosinophilic airway inflammation in muco-obstructive lung diseases, which may be mediated in part by ICAM-1-dependent transmigration of eosinophils into the lungs.

Lung eosinophilia induced by house dust mites or ovalbumin is modulated by nicotinic receptor α7 and inhibited by cigarette smoke.

Eosinophilia (EOS) is an important component of airway inflammation and hyperresponsiveness in allergic reactions including those leading to asthma. Although cigarette smoking (CS) is a significant contributor to long-term adverse outcomes in these lung disorders, there are also the curious reports of its ability to produce acute suppression of inflammatory responses including EOS through poorly understood mechanisms. One possibility is that proinflammatory processes are suppressed by nicotine in CS acting through nicotinic receptor α7 (α7). Here we addressed the role of α7 in modulating EOS with two mouse models of an allergic response: house dust mites (HDM; Dermatophagoides sp.) and ovalbumin (OVA). The influence of α7 on EOS was experimentally resolved in wild-type mice or in mice in which a point mutation of the α7 receptor (α7E260A:G) selectively restricts normal signaling of cellular responses. RNA analysis of alveolar macrophages and the distal lung epithelium indicates that normal α7 function robustly impacts gene expression in the epithelium to HDM and OVA but to different degrees. Notable was allergen-specific α7 modulation of Ccl11 and Ccl24 (eotaxins) expression, which was enhanced in HDM but suppressed in OVA EOS. CS suppressed EOS induced by both OVA and HDM, as well as the inflammatory genes involved, regardless of α7 genotype. These results suggest that EOS in response to HDM or OVA is through signaling pathways that are modulated in a cell-specific manner by α7 and are distinct from CS suppression.

Blomia tropicalis allergen 5 (Blo t 5) T-cell epitopes and their ability to suppress the allergic immune response.

Blomia tropicalis is the major asthma allergen in the tropics comparable to Dermatophagoides pteronyssinus. However, little is known about the B. tropicalis epitopes recognized by T cells. Our aim was to identify the T-cell epitopes in the major B. tropicalis allergen, Blo t 5, and investigate the potential of the corresponding peptides to inhibit the allergic inflammatory lung response. C57BL/6 mice were immunized with plasmid DNA encoding Blo t 5 and T-cell epitopes identified using the interferon-γ ELISPOT assay with 15-mer overlapping peptides. C57BL/6 mice were sensitized with bone-marrow-derived dendritic cells (BMDC) pulsed with Blo t 5 allergen followed by intranasal Blo t 5 challenge. Two H-2b restricted epitopes (Bt576-90 and Bt5106-115 ) were recognized by CD4 T cells specific for Blo t 5, but no CD8 epitopes were identified. In mice sensitized with Blo t 5-pulsed BMDC and challenged with intranasal Blo t 5 Bt576-90 and Bt5106-115 , peptide-specific CD4 T cells were found to secrete the T helper type 2 cytokines interleukin-5 and interleukin-13. Intradermal administration of synthetic peptides encoding the identified T-cell epitopes suppressed allergic airway inflammation to further allergen challenges. Hence, we have identified novel CD4 T-cell epitopes specific for Blo t 5 and demonstrated that these peptides could be employed therapeutically to suppress the T-cell response in a murine model of allergic airway inflammation.

Urtica dioica attenuates ovalbumin-induced inflammation and lipid peroxidation of lung tissues in rat asthma model.

CONTEXT: To find bioactive medicinal herbs exerting anti-asthmatic activity, we investigated the effect of an aqueous extract of Urtica dioica L. (Urticaceae) leaves (UD), the closest extract to the Algerian traditional use. OBJECTIVE: In this study, we investigated the in vivo anti-asthmatic and antioxidant activities of nettle extract. MATERIALS AND METHODS: Adult male Wistar rats were divided into four groups: Group I: negative control; group II: Ovalbumin sensitized/challenged rats (positive control); group III: received UD extract (1.5 g/kg/day) orally along the experimental protocol; group IV: received UD extract (1.5 g/kg/day) orally along the experimental protocol and sensitized/challenged with ovalbumin. After 25 days, blood and tissue samples were collected for haematological and histopathological analysis, respectively. The oxidative stress parameters were evaluated in the lungs, liver and erythrocytes. Then, correlations between markers of airway inflammation and markers of oxidative stress were explored. RESULTS: UD extract significantly (p < 0.01) inhibited eosinophilia increases in BALF (-60%) and the levels of leucocytes (-32.75%) and lymphocytes (-29.22%) in serum, and effectively suppressed inflammatory cells recruitment in the asthmatic rat model. Besides, the lipid peroxidation generated by allergen administration was significantly (p < 0.05) diminished by UD treatment in lung tissue (-48.58%). The nettle extract was also investigated for the total phenolic content (30.79 ± 0.96 mg gallic acid/g dry extract) and shows DPPH radical scavenging activity with 152.34 ± 0.37 µg/mL IC50 value. CONCLUSIONS: The results confirmed that UD administration might be responsible for the protective effects of this extract against airway inflammation.

Bach2 regulates homeostasis of Foxp3+ regulatory T cells and protects against fatal lung disease in mice.

Variants of the Bach2 gene are linked to vitiligo, celiac disease, and type 1 diabetes, but the underlying immunological mechanisms are unknown. In this study, we demonstrate that Bach2 plays crucial roles in maintaining T cell quiescence and governing the differentiation, activation, and survival of Foxp3(+) regulatory T (Treg) cells. Bach2-deficient T cells display spontaneous activation and produce elevated levels of Th1/Th2-type cytokines. Without Bach2, Treg cells exhibit diminished Foxp3 expression, depleted numbers, hyperactivation, enhanced proliferation, and profound loss of competitive fitness in vivo. Mechanistically, reduced survival of Bach2-deficient Treg cells was associated with reduced Bcl-2 and Mcl-1 levels and elevated Bim/Bcl-2 ratio. Additionally, Bach2 deficiency induced selective loss of Helios(-)Foxp3(+) Treg cells and a Treg cell transcriptome skewed toward the Th1/Th2 effector program at the expense of the Treg program. In vitro experiments confirmed that Bach2: 1) is indispensable for TCR/TGF-ß-induced Foxp3 expression; and 2) mitigates aberrant differentiation of Treg cells by repression of the competing Gata3-driven Th2 effector program. Importantly, perturbations in the differentiation of induced Treg cells was linked to a fatal Th2-type chronic inflammatory lung disease in Bach2-deficient mice. Thus, Bach2 enforces T cell quiescence, promotes the development and survival of Treg lineage, restrains aberrant differentiation of Treg cells, and protects against immune-mediated diseases.

Serotonin 5-HT2 receptor activation prevents allergic asthma in a mouse model.

Asthma is an inflammatory disease of the lung characterized by airways hyper-responsiveness (AHR), inflammation, and mucus hyperproduction. Current mainstream therapies include bronchodilators that relieve bronchoconstriction and inhaled glucocorticoids to reduce inflammation. The small molecule hormone and neurotransmitter serotonin has long been known to be involved in inflammatory processes; however, its precise role in asthma is unknown. We have previously established that activation of serotonin 5-hydroxytryptamine (5-HT)(2A) receptors has potent anti-inflammatory activity in primary cultures of vascular tissues and in the whole animal in vasculature and gut tissues. The 5-HT(2A) receptor agonist, (R)-2,5-dimethoxy-4-iodoamphetamine [(R)-DOI] is especially potent. In this work, we have examined the effect of (R)-DOI in an established mouse model of allergic asthma. In the ovalbumin mouse model of allergic inflammation, we demonstrate that inhalation of (R)-DOI prevents the development of many key features of allergic asthma, including AHR, mucus hyperproduction, airways inflammation, and pulmonary eosinophil recruitment. Our results highlight a likely role of the 5-HT2 receptors in allergic airways disease and suggest that 5-HT2 receptor agonists may represent an effective and novel small molecule-based therapy for asthma.

Protective effect of a Protein Epitope Mimetic CCR10 antagonist, POL7085, in a model of allergic eosinophilic airway inflammation.

BACKGROUND: Potential involvement of the CCR10/CCL28 axis was recently reported in murine models of allergic asthma. If confirmed, blockade of the CCR10 receptor would represent an alternative to current asthma therapies. We evaluated the effect of a novel Protein Epitope Mimetic CCR10 antagonist, POL7085, in a murine model of allergic eosinophilic airway inflammation. METHODS: Mice were sensitized and challenged to ovalbumin. POL7085, a CCR10 antagonist (7.5 and 15 mg/kg), dexamethasone (1 mg/kg) or vehicle were administered intranasally once daily 1h before each allergen challenge. On day 21, airway hyperresponsiveness, bronchoalveolar lavage inflammatory cells and Th2 cytokines, and lung tissue mucus and collagen were measured. RESULTS: Allergen challenge induced airway hyperresponsiveness in vehicle-treated animals as measured by whole body barometric plethysmography, and eosinophilia in bronchoalveolar lavage. POL7085 dose-dependently and significantly decreased airway hyperresponsiveness (34 ± 16 %) and eosinophil numbers in bronchoalveolar lavage (66 ± 6 %). In addition, the highest dose of POL7085 used significantly inhibited lung IL-4 (85 ± 4 %), IL-5 (87 ± 2 %) and IL-13 (190 ± 19 %) levels, and lung collagen (43 ± 11 %). CONCLUSIONS: The Protein Epitope Mimetic CCR10 antagonist, POL7085, significantly and dose-dependently decreased allergen-induced airway hyperresponsiveness and airway inflammation after once daily local treatment. Our data give strong support for further investigations with CCR10 antagonists in asthmatic disease.

Dietary galacto-oligosaccharides prevent airway eosinophilia and hyperresponsiveness in a murine house dust mite-induced asthma model.

BACKGROUND: Allergic asthma is strongly associated with the exposure to house dust mite (HDM) and is characterized by eosinophilic pulmonary inflammation and airway hyperresponsiveness (AHR). Recently, there is an increased interest in using dietary oligosaccharides, also known as prebiotics, as a novel strategy to prevent the development of, or reduce, symptoms of allergy. AIM: We investigated the preventive capacity of dietary galacto-oligosaccharides (GOS) compared to an intra-airway therapeutic treatment with budesonide on the development of HDM-induced allergic asthma in mice. METHODS: BALB/c mice were intranasally sensitized with 1 µg HDM on day 0 followed by daily intranasal challenge with PBS or 10 µg HDM on days 7 to 11. Two weeks prior to the first sensitization and throughout the experiment mice were fed a control diet or a diet containing 1% GOS. Reference mice were oropharyngeally instilled with budesonide (500 µg/kg) on days 7, 9, 11, and 13, while being fed the control diet. On day 14, AHR was measured by nebulizing increasing doses of methacholine into the airways. At the end of the experiment, bronchoalveolar lavage fluid (BALF) and lungs were collected. RESULTS: Sensitization and challenge with HDM resulted in AHR. In contrast to budesonide, dietary intervention with 1% GOS prevented the development of AHR. HDM sensitization and challenge resulted in a significant increase in BALF leukocytes numbers, which was suppressed by budesonide treatment and dietary intervention with 1% GOS. Moreover, HDM sensitization and challenge resulted in significantly enhanced concentrations of IL-6, CCL17, IL-33, CCL5 and IL-13 in lung tissue. Both dietary intervention with 1% GOS or budesonide treatment significantly decreased the HDM-induced increased concentrations of CCL5 and IL-13 in lung tissue, while budesonide also reduced the HDM-enhanced concentrations of IL-6 and CCL17 in lung tissue. CONCLUSION: Not only did dietary intervention with 1% GOS during sensitization and challenge prevent the induction of airway eosinophilia and Th2-related cytokine and chemokine concentrations in the lung equally effective as budesonide treatment, it also prevented AHR development in HDM-allergic mice. GOS might be useful for the prevention and/or treatment of symptoms in asthmatic disease.

Pulmonary edema measured by MRI correlates with late-phase response to allergen challenge.

PURPOSE: Asthma is associated with reversible airway obstruction, leucocyte infiltration, airways hyperresponsiveness (AHR), and airways remodeling. Fluid accumulation causes pulmonary edema contributing to airways obstruction. We examined the temporal relationship between the late asthmatic response (LAR) following allergen challenge of sensitized guinea-pigs and pulmonary edema measured by magnetic resonance imaging (MRI). MATERIALS AND METHODS: Ovalbumin (OVA) sensitized guinea-pigs received either a single OVA inhalation (acute) or nine OVA inhalations at 48 h intervals (chronic). Airways obstruction was measured as specific airways conductance (sG(aw)) by whole body plethysmography. AHR to inhaled histamine and bronchoalveolar lavage for leucocyte counts were measured 24 h after a single or the final chronic ovalbumin challenges. MRI was performed at intervals after OVA challenge and high-intensity edemic signals were quantified. RESULTS: Ovalbumin caused early bronchoconstriction, followed at 7 h by an LAR and at 24 h AHR and leucocyte influx. The bright-intensity MRI edema signal, peaking at 7 h, was significantly (P < .05) greater after chronic (9.0 ± 0.7 × 10(3) mm(3)) than acute OVA (7.6 ± 0.2 × 10(3) mm(3)). Dexamethasone treatment before acute OVA abolished the AHR and LAR and significantly reduced eosinophils and the bright-intensity MRI edema from 9.1 ± 1.0 to 6.4 ± 0.3 × 10(3) mm(3). CONCLUSION: We show a temporal relationship between edema and the LAR and their parallel reduction, along with eosinophils and AHR, by dexamethasone. This suggests a close causative association between pulmonary edema and impaired airways function.

Dietary long-chain omega-3 fatty acids do not diminish eosinophilic pulmonary inflammation in mice.

Although the effects of fish oil supplements on airway inflammation in asthma have been studied with varying results, the independent effects of the fish oil components, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), administered separately, are untested. Here, we investigated airway inflammation and hyperresponsiveness using a mouse ovalbumin exposure model of asthma assessing the effects of consuming EPA (1.5% wt/wt), DHA (1.5% wt/wt), EPA plus DHA (0.75% each), or a control diet with no added omega-3 polyunsaturated fatty acids. Consuming these diets for 6 weeks resulted in erythrocyte membrane EPA contents (molar %) of 9.0 (± 0.6), 3.2 (± 0.2), 6.8 (± 0.5), and 0.01 (± 0.0)%; DHA contents were 6.8 (± 0.1), 15.6 (± 0.5), 12.3 (± 0.3), and 3.8 (± 0.2)%, respectively. The DHA group had the highest bronchoalveolar lavage (BAL) fluid eosinophil and IL-6 levels (P < 0.05). Similar trends were seen for macrophages, IL-4, and IL-13, whereas TNF-α was lower in omega-3 polyunsaturated fatty acid groups than the control (P < 0.05). The DHA group also had the highest airway resistance, which differed significantly from the EPA plus DHA group (P < 0.05), which had the lowest. Oxylipins were measured in plasma and BAL fluid, with DHA and EPA suppressing arachidonic acid-derived oxylipin production. DHA-derived oxylipins from the cytochrome P450 and 15-lipoxygenase pathways correlated significantly with BAL eosinophil levels. The proinflammatory effects of DHA suggest that the adverse effects of individual fatty acid formulations should be thoroughly considered before any use as therapeutic agents in asthma.

Perillyl alcohol suppresses antigen-induced immune responses in the lung.

Perillyl alcohol (POH) is an isoprenoid which inhibits farnesyl transferase and geranylgeranyl transferase, key enzymes that induce conformational and functional changes in small G proteins to conduct signal production for cell proliferation. Thus, it has been tried for the treatment of cancers. However, although it affects the proliferation of immunocytes, its influence on immune responses has been examined in only a few studies. Notably, its effect on antigen-induced immune responses has not been studied. In this study, we examined whether POH suppresses Ag-induced immune responses with a mouse model of allergic airway inflammation. POH treatment of sensitized mice suppressed proliferation and cytokine production in Ag-stimulated spleen cells or CD4(+) T cells. Further, sensitized mice received aerosolized OVA to induce allergic airway inflammation, and some mice received POH treatment. POH significantly suppressed indicators of allergic airway inflammation such as airway eosinophilia. Cytokine production in thoracic lymph nodes was also significantly suppressed. These results demonstrate that POH suppresses antigen-induced immune responses in the lung. Considering that it exists naturally, POH could be a novel preventive or therapeutic option for immunologic lung disorders such as asthma with minimal side effects.

Small interfering RNA against CD86 during allergen challenge blocks experimental allergic asthma.

BACKGROUND: CD86-CD28 interaction has been suggested as the principal costimulatory pathway for the activation and differentiation of naïve T cells in allergic inflammation. However, it remains uncertain whether this pathway also has an essential role in the effector phase. We sought to determine the contribution of CD86 on dendritic cells in the reactivation of allergen-specific Th2 cells. METHODS: We investigated the effects of the downregulation of CD86 by short interfering RNAs (siRNAs) on Th2 cytokine production in the effector phase in vitro and on asthma phenotypes in ovalbumin (OVA)-sensitized and -challenged mice. RESULTS: Treatment of bone marrow-derived dendritic cells (BMDCs) with CD86 siRNA attenuated LPS-induced upregulation of CD86. CD86 siRNA treatment impaired BMDCs' ability to activate OVA-specific Th2 cells. Intratracheal administration of CD86 siRNA during OVA challenge downregulated CD86 expression in the airway mucosa. CD86 siRNA treatment ameliorated OVA-induced airway eosinophilia, airway hyperresponsiveness, and the elevations of OVA-specific IgE in the sera and IL-5, IL-13, and CCL17 in the bronchoalveolar lavage fluid, but not the goblet cell hyperplasia. CONCLUSION: These results suggest that local administration of CD86 siRNA during the effector phase ameliorates lines of asthma phenotypes. Targeting airway dendritic cells with siRNA suppresses airway inflammation and hyperresponsiveness in an experimental model of allergic asthma.

Obese mice are resistant to eosinophilic airway inflammation induced by diesel exhaust particles.

Particulate matter can exacerbate respiratory diseases such as asthma. Diesel exhaust particles are the substantial portion of ambient particulate matter with a <2.5 µm diameter in urban areas. Epidemiological data indicate increased respiratory health effects of particulate matter in obese individuals; however, the association between obesity and diesel exhaust particle-induced airway inflammation remains unclear. We aimed to investigate the differences in susceptibility to airway inflammation induced by exposure to diesel exhaust particles between obese mice (db/db) and lean mice (db/+m). Female db/db and db/+m mice were intratracheally administered diesel exhaust particles or vehicle every 2 weeks for a total of seven times. The cellular profile of bronchoalveolar lavage fluid and histological changes in the lungs were assessed and the lungs and serum were analyzed for the generation of cytokines, chemokines and soluble intercellular adhesion molecule 1. Diesel exhaust particle exposure-induced eosinophilic infiltration in db/+m mice accompanied by T-helper 2 cytokine, chemokine and soluble intercellular adhesion molecule 1 expression in the lungs. In contrast, it induced mild neutrophilic airway inflammation accompanied by elevated cytokines and chemokines in db/db mice. The lungs of db/db mice exhibited decreased expression of eosinophil activators/chemoattractants such as interleukin-5, interleukin-13 and eotaxin compared with those of db/+m mice. In addition, serum eotaxin and monocyte chemotactic protein-1 levels were significantly higher in db/db mice than in db/+m mice. In conclusion, obesity can affect susceptibility to diesel exhaust particle-induced airway inflammation, which is possibly due to differences in local and systemic inflammatory responses between lean and obese individuals.

Mepolizumab for severe eosinophilic asthma (DREAM): a multicentre, double-blind, placebo-controlled trial.

BACKGROUND: Some patients with severe asthma have recurrent asthma exacerbations associated with eosinophilic airway inflammation. Early studies suggest that inhibition of eosinophilic airway inflammation with mepolizumab-a monoclonal antibody against interleukin 5-is associated with a reduced risk of exacerbations. We aimed to establish efficacy, safety, and patient characteristics associated with the response to mepolizumab. METHODS: We undertook a multicentre, double-blind, placebo-controlled trial at 81 centres in 13 countries between Nov 9, 2009, and Dec 5, 2011. Eligible patients were aged 12-74 years, had a history of recurrent severe asthma exacerbations, and had signs of eosinophilic inflammation. They were randomly assigned (in a 1:1:1:1 ratio) to receive one of three doses of intravenous mepolizumab (75 mg, 250 mg, or 750 mg) or matched placebo (100 mL 0·9% NaCl) with a central telephone-based system and computer-generated randomly permuted block schedule stratified by whether treatment with oral corticosteroids was required. Patients received 13 infusions at 4-week intervals. The primary outcome was the rate of clinically significant asthma exacerbations, which were defined as validated episodes of acute asthma requiring treatment with oral corticosteroids, admission, or a visit to an emergency department. Patients, clinicians, and data analysts were masked to treatment assignment. Analyses were by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT01000506. FINDINGS: 621 patients were randomised: 159 were assigned to placebo, 154 to 75 mg mepolizumab, 152 to 250 mg mepolizumab, and 156 to 750 mg mepolizumab. 776 exacerbations were deemed to be clinically significant. The rate of clinically significant exacerbations was 2·40 per patient per year in the placebo group, 1·24 in the 75 mg mepolizumab group (48% reduction, 95% CI 31-61%; p<0·0001), 1·46 in the 250 mg mepolizumab group (39% reduction, 19-54%; p=0·0005), and 1·15 in the 750 mg mepolizumab group (52% reduction, 36-64%; p<0·0001). Three patients died during the study, but the deaths were not deemed to be related to treatment. INTERPRETATION: Mepolizumab is an effective and well tolerated treatment that reduces the risk of asthma exacerbations in patients with severe eosinophilic asthma. FUNDING: GlaxoSmithKline.

Physicochemical and biological characterization of synthetic phosphatidylinositol dimannosides and analogues.

Native phosphatidylinositol mannosides (PIMs), isolated from the cell wall of Mycobacterium bovis, and synthetic PIM analogues have been reported to offer a variety of immunomodulating properties, including both suppressive and stimulatory activity. While numerous studies have examined the biological activity of these molecules, the aim of this research was to assess the physicochemical properties at a molecular level and correlate these characteristics with biological activity in a mouse model of airway eosinophilia. To accomplish this, we varied the flexibility and lipophilicity of synthetic PIMs by changing the polar headgroup (inositol- vs glycerol-based core) and the length of the acyl chains of the fatty acid residues (C0, C10, C16, and C18). A series of six phosphatidylinositol dimannosides (PIM2s) and phosphatidylglycerol dimannosides (PGM2s) were synthesized and characterized in this study. Langmuir monolayer studies showed that surface pressure-area (π-A) isotherms were greatly influenced by the length of the lipid acyl chains as well as the steric hindrance and volume of the headgroups. In aqueous solution, lipidated PIM2 and PGM2 compounds were observed to self-assemble into circular aggregates, as confirmed by dynamic light scattering and transmission electron microscopic investigations. Removal of the inositol ring but retention of the three-carbon glycerol unit maintained biological activity. We found that the deacylated PGM2, which did not show self-organization, had no effect on the eosinophil numbers but did have an impact on the expansion of OVA-specific CD4(+) Vα2Vß5 T cells.

[Can eosinophilic bronchitis be considered as an occupational disease? Medical certification aspects]. / Czy eozynofilowe zapalenie oskrzeli mozna zakwalifikowac do grupy chorób zawodowych? aspekty orzecznictwa lekarskiego.

Eosinophilic bronchitis (EB) is a condition which can be associated with occupational exposure to low, as well as to high molecular weight allergens. The prevalence of occupational eosinophilic bronchitis is unknown and the data concerning its work-related etiology are available only from the case reports. However, there is a need to establish the principles, especially in the context of medical certification among workers occupationally exposed to allergens. This paper reviews current knowledge on the etiology, clinical features, and diagnostic procedures in the eosinophilic bronchitis. The importance of EB, especially in view of the problems emerging in the prophylactic care taken by occupational health services and the principles of medical certification when occupational etiology is suspected are also presented.

Pharmacologic profile of OC000459, a potent, selective, and orally active D prostanoid receptor 2 antagonist that inhibits mast cell-dependent activation of T helper 2 lymphocytes and eosinophils.

D prostanoid receptor 2 (DP2) [also known as chemoattractant receptor-homologous molecule expressed on T helper 2 (Th2) cells (CRTH2)] is selectively expressed by Th2 lymphocytes, eosinophils, and basophils and mediates recruitment and activation of these cell types in response to prostaglandin D2 (PGD2). (5-Fluoro-2-methyl-3-quinolin-2-ylmethylindo-1-yl)-acetic acid (OC000459) is an indole-acetic acid derivative that potently displaces [³H]PGD2 from human recombinant DP2 (K(i) = 0.013 µM), rat recombinant DP2 (K(i) = 0.003 µM), and human native DP2 (Th2 cell membranes; K(i) = 0.004 µM) but does not interfere with the ligand binding properties or functional activities of other prostanoid receptors (prostaglandin E1₋4 receptors, D prostanoid receptor 1, thromboxane receptor, prostacyclin receptor, and prostaglandin F receptor). OC000459 inhibited chemotaxis (IC50 = 0.028 µM) of human Th2 lymphocytes and cytokine production (IC50 = 0.019 µM) by human Th2 lymphocytes. OC000459 competitively antagonized eosinophil shape change responses induced by PGD2 in both isolated human leukocytes (pK(B) = 7.9) and human whole blood (pK(B) = 7.5) but did not inhibit responses to eotaxin, 5-oxo-eicosatetraenoic acid, or complement component C5a. OC000459 also inhibited the activation of Th2 cells and eosinophils in response to supernatants from IgE/anti-IgE-activated human mast cells. OC000459 had no significant inhibitory activity on a battery of 69 receptors and 19 enzymes including cyclooxygenase 1 (COX1) and COX2. OC000459 was found to be orally bioavailable in rats and effective in inhibiting blood eosinophilia induced by 13,14-dihydro-15-keto-PGD2 (DK-PGD2) in this species (ED50 = 0.04 mg/kg p.o.) and airway eosinophilia in response to an aerosol of DK-PGD2 in guinea pigs (ED50 = 0.01 mg/kg p.o.). These data indicate that OC000459 is a potent, selective, and orally active DP2 antagonist that retains activity in human whole blood and inhibits mast cell-dependent activation of both human Th2 lymphocytes and eosinophils.

Prophylactic Vaccine Targeting TLR3 on Dendritic Cells Ameliorates Eosinophilic Pneumonia in a Mouse SARS-CoV Infection Model.

Putative subcomponent vaccines of severe acute respiratory syndrome coronavirus spike protein and ARNAX (TLR3-specific adjuvant for priming dendritic cells) were examined and compared with spike protein + Alum in a mouse BALB/c model. Survival, body weight, virus-neutralizing Ab titer in the blood, and viral titer in the lung were evaluated for prognosis markers. The infiltration degrees of eosinophils in the lung were histopathologically monitored at 10 d postinfection. The results were: (1) adjuvant was essential in vaccines to achieve a complete recovery from infection, (2) ARNAX displayed optimal body weight recovery compared with Alum, (3) ARNAX was optimal for the amelioration of eosinophilic pneumonia, and (4) the eosinophil infiltration score was not associated with the neutralizing Ab titer in the blood or viral titer in the lung. Although the pathological link between the TLR3 vaccine and lung eosinophil infiltration remains unclear, severe acute respiratory syndrome-mediated eosinophilic pneumonia can be blocked by the prior induction of dendritic cell priming by ARNAX.

Genetic and pharmacological evaluation of cathepsin s in a mouse model of asthma.

Cathepsin S (Cat S) is predominantly expressed in antigen-presenting cells and is up-regulated in several preclinical models of antigen-induced inflammation, suggesting a role in the allergic response. Prophylactic dosing of an irreversible Cat S inhibitor has been shown to attenuate pulmonary eosinophilia in mice, supporting the hypothesis that Cat S inhibition before the initiation of airway inflammation is beneficial in airway disease. In addition, Cat S has been shown to play a role in more distal events in the allergic response. To determine where Cat S inhibition may affect the allergic response, we used complementary genetic and pharmacological approaches to investigate the role of Cat S in the early and downstream allergic events in a murine model of antigen-induced lung inflammation. Cat S knockout mice did not develop ovalbumin-induced pulmonary inflammation, consistent with a role for Cat S in the development of the allergic response. Alternatively, wild-type mice were treated with a reversible, highly selective Cat S inhibitor in prophylactic and therapeutic dosing paradigms and assessed for changes in airway inflammation. Although both treatment paradigms resulted in potent Cat S inhibition, only prophylactic Cat S inhibitor dosing blocked lung inflammation, consistent with our findings in Cat S knockout mice. The findings indicate that although Cat S is up-regulated in allergic models, it does not appear to play a significant role in the downstream effector inflammatory phase in this model; however, our results demonstrate that Cat S inhibition in a prophylactic paradigm would ameliorate airway inflammation.

Cigarette smoke differentially affects eosinophilia and remodeling in a model of house dust mite asthma.

Although a similar prevalence of smoking is evident among patients with asthma and the general population, little is known about the impact of cigarette smoke on the immune inflammatory processes elicited by common environmental allergens. We investigated the impact of exposure to cigarette smoke on house dust mite (HDM)-induced allergic airway inflammation and its consequences for tissue remodeling and lung physiology in mice. BALB/c mice received intranasal HDMs daily, 5 days per week, for 3 weeks to establish chronic airway inflammation. Subsequently, mice were concurrently exposed to HDMs plus cigarette smoke, 5 days per week, for 2 weeks (HDMs + smoke). We observed significantly attenuated eosinophilia in the bronchoalveolar lavage of mice exposed to HDMs + smoke, compared with animals exposed only to HDMs. A similar activation of CD4 T cells and expression of IL-5, IL-13, and transforming growth factor-ß was observed between HDM-treated and HDM + smoke-treated animals. Consistent with an effect on eosinophil trafficking, HDMs + smoke exposure attenuated the HDM-induced expression of eotaxin-1 and vascular cell adhesion molecule-1, whereas the survival of eosinophils and the numbers of blood eosinophils were not affected. Exposure to cigarette smoke also reduced the activation of B cells and the concentrations of serum IgE. Although the production of mucus decreased, collagen deposition significantly increased in animals exposed to HDMs + smoke, compared with animals exposed only to HDMs. Although airway resistance was unaffected, tissue resistance was significantly decreased in mice exposed to HDMs + smoke. Our findings demonstrate that cigarette smoke affects eosinophil migration without affecting airway resistance or modifying Th2 cell adaptive immunity in a murine model of HDM-induced asthma.