Bronchoalveolar Lavage Eosinophils Research Articles

Lavender essential oil inhalation suppresses allergic airway inflammation and mucous cell hyperplasia in a murine model of asthma

AimsLavender essential oil (Lvn) has been reported to have anti-inflammatory effects. Bronchial asthma is characterized by bronchial allergic inflammation with airway remodeling. Therefore, we evaluated the anti-inflammatory effect of Lvn on experimentally induced bronchial asthma in a murine model. Main methodsBALB/c mice were sensitized by an intraperitoneal injection of ovalbumin (OVA) at days 0 and 14, and subsequently challenged with nebulized OVA on days 28–30 (Control-Asthma group). Mice in the treatment group inhaled Lvn on days 14–31 (Lvn-Asthma group). The allergic inflammatory response was determined on days 32 and 33. Key findingsAn increase in airway resistance was inhibited in the Lvn-Asthma group than in the Control-Asthma group. The Lvn-Asthma group showed lower total cell numbers and eosinophils in bronchoalveolar lavage (BAL) fluids and peribronchial and perivascular tissues when compared with the Control-Asthma group. The Lvn-Asthma group also had less mucin hyperplasia than the Control-Asthma group. Furthermore, the Lvn-Asthma group showed lower interleukin (IL)-5 and IL-13 cytokine levels in BAL fluids, as well as reduced IL-4 and IL-5 mRNA expression in lung tissue, compared with the Control-Asthma group and determined by FlowCytomix and reverse transcriptase-polymerase chain reaction (RT-PCR), respectively. In addition, Lvn inhalation reduced Muc5b mRNA expression in the lungs without significantly changing the expression of Muc5ac mRNA. SignificanceLvn inhibits allergic inflammation and mucous cell hyperplasia with suppression of T-helper-2 cell cytokines and Muc5b expression in a murine model of asthma. Consequently, Lvn may be useful as an alternative medicine for bronchial asthma.

Leukotriene enhanced allergic lung inflammation through induction of chemokine production (HYP4P.414)

Abstract Leukotrienes, which are mainly expressed by mast cells, macrophages and eosinophils, have been shown to act as important mediators in allergic asthma. In addition to leukotrienes, IL-13, a Th2 specific cytokine, has also been considered as the most important effector cytokine to induce allergic asthma, by increasing airway hyper-responsiveness, airway inflammation, eosinophilia and mucus hyper-production. But, the exact mechanisms how leukotrienes elicit allergic lung responses at initial stage and the effect of leukotrienes on allergic asthma through IL-13 remain unclear. To reveal this, we adopted two distinct models of allergic inflammation: intranasal Aspergillus protease allergen and recombinant IL-13 induced Th2 mediated inflammation. Here we measured AHR, bronchoalveolar lavage cytology, glycoprotein secretion, as well as IL-13 related chemokines such as CCL7, CCL11 and CCL17, which directly regulate homing of Th2 cells to lung with 5-lipoxygenase deficient and wild type mice. 5-lipoxygenase that convert arachidonic acid into leukotriene A4 null mice showed attenuated airway inflammation, AHR and bronchoalveolar lavage eosinophilia, as well as diminished chemokines including CCL7 and CCL17. Finally, addition of LTB4 and LTC4 to the airways of 5-lipoxygenase deficient mice restored rIL-13 induced asthma. Thus, our results indicate that LTs augment the effect of IL-13 in allergic asthma, are required for Th2 specific chemokine production.

Effect of NADPH oxidase 2 (Nox2) deficiency on the function of Th2 cells (HYP4P.415)

Abstract Nox2/gp91phox, one of phagocyte NADPH oxidase subunits, is mainly expressed on phagocytes. They transport electrons across the plasma membranes and kill pathogens by producing ROS. Many evidences have shown that Nox2 deficiency causes susceptibility to infections and immunosuppression. Recent studies have identified functional phagocyte-type Nox2 is also expressed in helper T cells through TCR stimulation. So, many papers attempted to define the role of Nox2 on Th1 and Th17 cell differentiation, but the exact function of Nox2 in Th2 differentiation remains unclear. To elucidate this, we adopted experimental allergic asthma that Th2 cells have been considered as a pivotal mediator for asthma pathogenesis. Here, we revealed that Nox2 deficient mice showed enhanced allergic asthma phenotypes including increased airway hyper responsiveness, eosinophilia, glycoprotein secretion and IL-4 production in bronchoalveolar lavage through augmented Th2 differentiation, regardless of challenge routes and allergen types. Based on our results, we conclude that Nox2 could be a molecular target for controlling Th2 cell differentiation and allergic asthma.

Kinetics of inflammation and leukocyte recruitment in a murine model of asthma: eosinophils versus neutrophils (HYP7P.284)

Abstract Murine model of ovalbumin-induced allergic inflammation remains to be a popular choice for approximating human acute asthma condition. Despite its widespread usage, exact timing and sequence of inflammatory events in this model remain obscure. We used a BALB/cJ mouse model with two intraperitoneal sensitizations and six intranasal challenges, and monitored inflammatory parameters at 6 and 24 hours after each ovalbumin challenge. Multicolor flow cytometry was used to assess recruitment dynamics of leukocytes in the digested lung tissue and bronchoalveolar lavage (BAL). Although neutrophil recruitment dominated the initial response to allergen, eosinophils started to appear almost simultaneously, gradually increasing their presence with each challenge. Interestingly, while still present in the lung tissue, neutrophils ceased mucosal surveillance (measured as BAL infiltrate) after three challenges, at which time point eosinophilia increased dramatically. This increase in BAL eosinophilia correlated with upregulation of integrin CD11c by CD11b+Siglec-F+Ly6Glow eosinophils in the tissue. Mediators such as IL-4, IL-6, IL-9 and IL-33 exhibited peak expression during the first three challenges. Other mediators, such as CCL11, IL-5, IL-13 and Slit2-roundabout signals were more prevalent later in the model. Collectively, our results demonstrate progression of events that govern presence of eosinophils versus neutrophils in the lung tissue and airways during allergic inflammation.

(276) - Elevated Hyaluronan Is Associated with Bronchiolitis Obliterans Syndrome

s S107 and bronchiolitis obliterans syndrome (BOS), of which the exact pathophysiology remain elusive. A previous study demonstrated that increased bronchoalveolar lavage eosinophilia predisposed to CLAD. We further investigated the presence of eosinophils in explants lung tissue of CLAD. Methods: Sections of BOS (n= 16) and RAS (n= 16) lungs were stained and quantified compared to (non-transplant) control lungs (n= 20). Eosinophils, identified by the marker EG2, were counted in three different compartments; around the airway, in the parenchyma and around the blood vessel. Results were represented as the mean number (±SEM) of cells per high power field. Results: Representative staining of BOS (A), RAS (B) and control (C) are provided in figure 1. Around the airways, eosinophils were significantly increased in BOS (16.7±4.8; p< 0.05) and in RAS (13.4±4.0; p< 0.05) compared to control (2.8±0.8). In the parenchyma, there were more eosinophils present in BOS (8.8±1.4; p< 0.05), but not in RAS (8.2±2.2), compared to control (3.9±0.9). Around the blood vessels, both BOS (11.4±2.1; p< 0.01) and RAS (9.8±1.9; p< 0.05) demonstrated an increased number of eosinophils compared to control (4.0±0.6). The number of eosinophils around the airways correlated with eosinophil numbers in the parenchyma (R= 0.55, p< 0.0001) and around the blood vessels (R= 0.79, p< 0.0001). Conclusion: Eosinophils, regulated by a Th2 immune response, are increased in BOS and RAS which may implicate a new pathway. These findings may lead to additional therapeutic options to improve outcome after LTx in the future.

(277) - An Immunohistological Study To Evaluate the Role of Eosinophils in Chronic Lung Allograft Dysfunction

Long term survival after lung transplantation (LTx) is restricted by the development of chronic lung allograft dysfunction (CLAD). CLAD represents at least 2 sub-phenotypes: restrictive allograft syndrome (RAS) and bronchiolitis obliterans syndrome (BOS), of which the exact pathophysiology remain elusive. A previous study demonstrated that increased broncho-alveolar lavage eosinophilia predisposed to CLAD. We further investigated the presence of eosinophils in explants lung tissue of CLAD.

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.

A limited CpG-containing oligodeoxynucleotide therapy regimen induces sustained suppression of allergic airway inflammation in mice

BackgroundCpG-containing oligodeoxynucleotides (CpG-ODNs) are potent inhibitors of T helper 2 mediated allergic airway disease in sensitised mice challenged with allergen. A single treatment has transient effects but a limited series...

Investigation of the Antiasthmatic Properties of Ethanol Extract of &lt;i&gt;Callophyllis japonica&lt;/i&gt; in Mice

Purpose: To determine whether an ethanol extract from Callophyllis japonica (C. japonica) could attenuate indices of airway inflammation in a murine model of ovalbumin (OVA)-induced asthma.Methods: The free radical scavenging activity of the C. japonica ethanol extracts (CJE) were investigated using an electron spin resonance (ESR) system. To make develop animal model of asthma, mice were sensitized and challenged with OVA.Results: CJE exhibited considerable scavenging activity of 71.08 ± 0.73, 79.11 ± 6.04%, 75.95 ± 7.01%, and 48.56 ± 5.96% of DPPH, alkyl, superoxide, and hydroxyl radicals, respectively. The successive intraperitoneal administration of CJE reduced the number of eosinophils in bronchoalveolar lavage (BAL) fluid, development of airway hyperresponsiveness (AHR), an increase in pulmonary Th2 cytokines, and allergen-specific immunoglobulin E (IgE).Conclusion: Administration of CJE markedly alleviates all indices of airway inflammation. This study provides evidence that CJE plays a critical role in the amelioration of the pathogenetic process of allergic asthma in mice.Keywords: Asthma, Phenolic contents, Free radical scavenging, Airway hyper-responsiveness, Cytokines, Immunoglobulin E

Elevated Bronchoalveolar Lavage Eosinophilia Correlates With Poor Outcome After Lung Transplantation

Eosinophils are involved in the pathophysiology of many respiratory diseases, but the exact role of eosinophilia in lung transplantation has not been thoroughly investigated. We performed a retrospective analysis of our transplanted patients between 2001 and 2011, with a minimum follow-up of 1 year. Using a cutoff of ≥2% eosinophilia in bronchoalveolar lavage (BAL) fluid, chronic lung allograft dysfunction (CLAD)-free survival and overall survival was compared between 66 patients demonstrating at least one BAL with eosinophils ≥2% and 253 control patients (never BAL ≥2%). Patients with increased BAL eosinophilia demonstrated worse CLAD-free and overall survival (both P<0.0001) compared with controls. Eosinophilic BAL predisposed to development of bronchiolitis obliterans syndrome but particularly to restrictive allograft syndrome (P<0.0001). After correction for covariates, the association between eosinophilic BAL and CLAD but equally death remained significant (P=0.0047 and 0.0011). Blood eosinophil and C-reactive protein levels were also elevated at the time of eosinophilic BAL. BAL eosinophilia ≥2% is associated with poor outcome in our lung transplant patients as demonstrated by worse CLAD-free and overall survival. Interestingly, increased BAL eosinophilia may be specifically associated with the development of restrictive allograft syndrome, which needs further prospective investigation.

Overexpression of dimethylarginine dimethylaminohydrolase 1 attenuates airway inflammation in a mouse model of asthma.

Levels of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, are increased in lung, sputum, exhaled breath condensate and plasma samples from asthma patients. ADMA is metabolized primarily by dimethylarginine dimethylaminohydrolase 1 (DDAH1) and DDAH2. We determined the effect of DDAH1 overexpression on development of allergic inflammation in a mouse model of asthma. The expression of DDAH1 and DDAH2 in mouse lungs was determined by RT-quantitative PCR (qPCR). ADMA levels in bronchoalveolar lavage fluid (BALF) and serum samples were determined by mass spectrometry. Wild type and DDAH1-transgenic mice were intratracheally challenged with PBS or house dust mite (HDM). Airway inflammation was assessed by bronchoalveolar lavage (BAL) total and differential cell counts. The levels of IgE and IgG1 in BALF and serum samples were determined by ELISA. Gene expression in lungs was determined by RNA-Seq and RT-qPCR. Our data showed that the expression of DDAH1 and DDAH2 was decreased in the lungs of mice following HDM exposure, which correlated with increased ADMA levels in BALF and serum. Transgenic overexpression of DDAH1 resulted in decreased BAL total cell and eosinophil numbers following HDM exposure. Total IgE levels in BALF and serum were decreased in HDM-exposed DDAH1-transgenic mice compared to HDM-exposed wild type mice. RNA-Seq results showed downregulation of genes in the inducible nitric oxide synthase (iNOS) signaling pathway in PBS-treated DDAH1-transgenic mice versus PBS-treated wild type mice and downregulation of genes in IL-13/FOXA2 signaling pathway in HDM-treated DDAH1-transgenic mice versus HDM-treated wild type mice. Our findings suggest that decreased expression of DDAH1 and DDAH2 in the lungs may contribute to allergic asthma and overexpression of DDAH1 attenuates allergen-induced airway inflammation through modulation of Th2 responses.

The effect of single dose of thymoquinone, the main constituents of Nigella sativa, in guinea pig model of asthma.

Introduction: In previous studies, the relaxant and antihistaminic effects of thymoquinone, the main constituents of Nigella sativa, have been demonstrated on guinea pig tracheal chains. In the present study, the prophylactic effect of (IP) single dose of thymoquinone on tracheal responsiveness and lung inflammation of guinea pig model of asthma was examined. Methods: Thirty guinea pigs were randomly divided to 3 groups; control (C), sensitized (S) and pretreated group with (TQ); 3 mg/kg, IP (S+TQ). Tracheal responsiveness to methacholine and ovalbumin (OA), total and differential cell count in bronchoalveolar lavage, lung pathological changes and blood Interleukin 4(IL-4) and Interferon gamma (IFNγ) level in three groups were measured. Results: Increased tracheal responsiveness to methacholine and OA, lung lavage fluid white blood cell (WBC) and eosinophil count, IL-4 and IFN-γ levels and pathological changes were seen in sensitized group in comparison to control group (p<0.001 to p<0.05). Decreased tracheal responsiveness to methacholine and OA, pathological changes and bronchoalveolar lavage eosinophil were observed in S+TQ group compared to S group (p<0.001 to p<0.05). However, tracheal responsiveness to methacholine and OA, contractility, bronchoalveolar lavage WBC and eosinophil and most of pathological changes in S+TQ group were significantly higher than those in controls (p<0.01 to p<0.05). Conclusion: These results showed the preventive effect of single dose of thymoquinone on guinea pig model of asthma.

Eosinophilic Bronchial Disorders Presenting Chronic Cough; Atopic Cough, Cough Variant Asthma and Non-Asthmatic Eosinophilic Bronchitis

Chronic persistent non-productive cough is troublesome, whereas productive cough is physiologic and acts to remove abnormal secretions and foreign bodies from the lower respiratory tract. Atopic cough is a new clinical entity for bronchodilator-resistant non-productive cough associated with generalized atopy. Pathological characteristics of atopic cough included trachea bronchitis without Broncho Alveolar Lavage (BAL) eosinophilia, and the physiological characteristics included hypersensitivity of the cough reflex without bronchial hyper reactivity. Patients with atopic cough have eosinophilia of the nebulized hypertonic saline-induced sputum but normal spirometry findings and no variability of Peak Expiratory Flow (PEF). These features of atopic cough are distinct from those of cough variant asthma, since these patients have mild bronchial hyper reactivity and eosinophilic inflammation of the central and peripheral airways and their cough is responsive to bronchodilator treatment. Moreover cough-variant asthma is a precursor of typical asthma, while atopic cough is not, because nearly 30% of patients with cough-variant asthma eventually develop typical asthma but patients with atopic cough do not. Although nearly 60% of patients with atopic cough can be successfully treated with histamine H1-receptor antagonists, but other still require additional corticosteroid therapy because bronchoscopic study indicate that bronchial eosinophilic inflammation is more severe in the H1-receptor antagonist-resistant group. Further investigations are required for the clinical entity of eosinophilic bronchitis without asthma, since it seems to resemble to atopic cough and there seems to be considerable overlap of these two clinical entities.

Additive anti-allergic effects of anti-interleukin-33 and anti-Siglec-F treatments in a murine model of allergic asthma.

BackgroundAnti-interleukin-33 (anti-IL-33) and anti-Siglec-F antibodies have potent anti-allergic effects on murine allergic asthma and rhinitis and induce eosinophil apoptosis.ObjectiveWe aimed to determine whether post-sensitization with anti-IL-33/anti-Siglec-F treatments exhibited more potent effects compared to individual treatments in a murine allergic asthma model.Material and methodsTwenty-five BALB/c mice were separated into five groups (n = 5): Group A (control), Group B (ovalbumin [OVA] challenge), Group C (OVA + anti-IL-33), Group D (OVA + anti-Siglec-F), and Group E (OVA + anti-IL-33 + anti-Siglec-F). Serum total/ OVA-specific IgE, bronchoalveolar lavage (BAL) inflammatory cells and cytokines (IL-4 and IL-5), histopathological lung properties, and airway hyperreactivity were compared.ResultsOvalbumin challenge induced strong immune and inflammatory responses with > 6-fold IgE level increases; 10- to 25-fold BAL eosinophil, neutrophil, and lymphocyte count increases; and > 1.5-fold IL-4 and IL-5 level increases (p < 0.05). Whereas anti-IL-33 reduced neutrophil counts, anti-Siglec-F and anti-IL-33/anti-Siglec-F reduced both eosinophil and neutrophil counts (p < 0.05). Individual treatments reduced OVA-mediated bronchiolar infiltration by 50% (p <0.05). Ovalbumin challenge increased airway hyperreactivity by 4-fold (Group B; 2000.0 ±671.8% increase in Penh) compared to controls (Group A; 445.7 ±33.5% increase in Penh) (p = 0.016). The anti-IL-33 (Group C: 1579.4 ±973.6% increase in Penh) and anti-Siglec-F (Group D: 930.4 ±236.5%) groups demonstrated significantly reduced hyperreactivity (p = 0.029). Anti-IL-33/anti-Siglec-F therapy showed synergism towards neutrophil counts, IL-5 concentrations, bronchial infiltration, and hyperreactivity (p < 0.05).ConclusionsCombination treatment with anti-IL-33/anti-Siglec-F had more potent anti-allergic effects, reducing eosinophilic infiltration through their additive effects in a murine allergic asthma model.

Semaphorin 7A is expressed on airway eosinophils and upregulated by IL-5 family cytokines

Semaphorin 7A (sema7a) plays a major role in TGF-β1-induced lung fibrosis. Based on the accumulating evidence that eosinophils contribute to fibrosis/remodeling in the airway, we hypothesized that airway eosinophils may be a significant source of sema7a. In vivo, sema7a was expressed on the surface of circulating eosinophils and upregulated on bronchoalveolar lavage eosinophils obtained after segmental bronchoprovocation with allergen. Based on mRNA levels in unfractionated and isolated bronchoalveolar cells, eosinophils are the predominant source of sema7a. In vitro, among the members of the IL-5-family cytokines, sema7a protein on the surface of blood eosinophils was increased more by IL-3 than by GM-CSF or IL-5. Cytokine-induced expression of cell surface sema7a required translation of newly synthesized protein. Finally, a recombinant sema7a induced alpha-smooth muscle actin production in human bronchial fibroblasts. semaphorin 7A is a potentially important modulator of eosinophil profibrotic functions in the airway remodeling of patients with chronic asthma.

Abr, a Negative Regulator of Rac, Attenuates Cockroach Allergen–Induced Asthma in a Mouse Model

Abr deactivates Ras-related C3 botulinum toxin substrate (Rac), a master molecular switch that positively regulates many immune cell functions, by converting it to its GDP-bound conformation. In this article, we report that, in the absence of Abr function, cockroach allergen (CRA)-immunized mice experienced a fatal asthma attack when challenged with CRA. The asthma in abr(-/-) mice was characterized by increased pulmonary mucus production, elevated serum IgE, and leukocyte airway infiltration. Decreased pulmonary compliance was further documented by increased airway resistance upon methacholine challenge. Peribronchial and bronchoalveolar lavage eosinophils, key cells associated with allergic asthma, were increased in abr(-/-) mice, but adoptive transfer of this cell type from immunized mice to naive controls, followed by CRA challenge, showed that eosinophils are not primarily responsible for differences in airway resistance between controls and abr-null mutants. CD4(+) T cell numbers in the airways of CRA-challenged abr(-/-) mice also were significantly increased compared with controls, as were the Th2 T cell-secreted cytokines IL-4 and IL-5 in total lung. Interestingly, when control and abr(-/-) CD4(+) T cells from CRA-immunized mice were transferred to wild-type animals, airway resistance upon challenge with CRA was significantly higher in mice transplanted with T cells lacking Abr function. CD4(+) T cells from CRA-immunized and challenged abr(-/-) mice contained elevated levels of activated GTP-bound Rac compared with wild-type controls. Functionally, abr(-/-) CD4(+) T cells from CRA-exposed mice showed significantly enhanced chemotaxis toward CCL21. These results identify Abr-regulated CD4(+) T cell migration as an important component of severe CRA-evoked allergic asthma in mice.

No exacerbation but impaired anti-viral mechanisms in a rhinovirus-chronic allergic asthma mouse model

Severe asthma and viral-induced asthma exacerbations represent a high unmet medical need as no therapy is currently available for these patients. HRV (human rhinovirus) is prominently associated with asthma exacerbations in humans. The aim of the present study was to establish a mouse model of severe asthma with additional rhinovirus infection to investigate the interplay between chronic allergic airway inflammation and acute respiratory viral infection. Balb/c mice were sensitized with HDM (house dust mite) extract (25μg in 50μl of saline) by i.n. (intranasal) delivery to the lung over 7weeks. HRV1B (HRV serotype 1B) inoculation was performed i.n. on the last 3days. Therapeutic treatment with FP (fluticasone propionate) was performed to assess steroid efficacy. Lung resistance was measured invasively to assess AHR (airway hyper-responsiveness). BAL (bronchoalveolar lavage) differential cell count, cytokines, lung histology and the proliferative and cytokine response of MLN (mediastinal lymph node) cells upon invitro restimulation were analysed. Chronic HDM application induced a strong Th2-skewed eosinophilic airway inflammation and AHR, which was not exacerbated by superimposed HRV1B infection. Therapeutic steroid intervention in the chronic HDM model reduced BAL eosinophil cell counts, cytokine levels and AHR, while neutrophil numbers were unaffected. Steroid efficacy against inflammatory readouts was maintained during additional HRV1B infection. Animals with chronic allergic airway inflammation exhibited a diminished immune response towards superimposed HRV1B infection compared with HRV1B alone, as induction of the anti-viral and pro-inflammatory cytokines IFN (interferon)-α, IFN-γ and IL (interleukin)-12 were suppressed. Although superimposed HRV1B infection did not provoke asthma exacerbation in this severe model, a deficient anti-viral immune response to HRV1B was present under chronic allergic airway inflammatory conditions. Thus, this model is able to reflect some aspects of the complex interplay of respiratory virus infection in chronic allergic asthma.

Teaching Neuro Images : Awakening ptosis (unilateral hypnopompic eyelid palsy)

The increasing prevalence of allergic airway diseases in industrialized countries has been associated with high hygienic standards and reduced microbial exposure. Probiotic lactic acid bacteria, such as certain <i>Lactobacillus</i> strains, were shown to have potentially beneficial immunomodulatory properties. Therefore, we determined the effect of intranasal administration of <i>L. rhamnosus</i> GG (LGG) and GR-1 (LGR-1) in a mouse model of birch pollen-induced allergic asthma. The symptoms of allergic asthma were induced with 7 intranasal applications with 1- or 2-day interval with birch pollen extract. The asthma induction protocol was preceded by 8 intranasal administrations of LGG or LGR-1 at a concentration of 5 x 10⁸ CFU/dose over the course of two weeks on four consecutive days each week. We assessed serum antibody levels, bronchoalveolar lavage (BAL) cell counts, lung histology, lung cytokine levels, airway hyperreactivity. LGG administration resulted in a significant decrease in allergic airway inflammation (BAL eosinophils, lung IL-13 and IL-5 levels) and a significantly reduced number of respiratory exacerbations. Contrary to LGG, no decisive results were obtained for LGR-1. Longitudinal <i>in vivo</i> lung micro-computed tomography (micro-CT) is currently ongoing to determine inflammatory exacerbation. Complementary to micro-CT, fluorescence imaging (FLI) of a fluorescent LGG strain will be performed to understand the probiotic-host interactions at the whole-body and whole-organ level. In conclusion, bacterial strain-specific beneficial effects of intranasally administered LGG were observed in a mouse model of birch pollen-induced allergic asthma.

IL-33 Signaling Regulates Innate and Adaptive Immunity to Cryptococcus neoformans

Susceptibility to progressive infection with the fungus Cryptococcus neoformans is associated with an allergic pattern of lung inflammation, yet the factors that govern this host response are not clearly understood. Using a clinically relevant mouse model of inhalational infection with virulent C. neoformans H99, we demonstrate a role for IL-33-dependent signaling in host immune defense. Infection of BALB/c mice with 10(4) CFU of C. neoformans H99 caused a time-dependent induction of IL-33 with accumulation of type 2 pulmonary innate lymphoid cells and alternatively activated macrophages in the lungs as well as Th2-polarized CD4(+) T cells in draining lymph nodes. IL-33R subunit T1/ST2-deficient (T1/ST2(-/-)) mice infected with C. neoformans H99 had improved survival with a decreased fungal burden in the lungs, spleen, and brain, compared with wild-type mice. Signaling through T1/ST2 was required for the accumulation and early production of IL-5 and IL-13 by lung type 2 pulmonary innate lymphoid cells. Further analysis of T1/ST2(-/-) mice revealed increased fungicidal exudate macrophages in the lungs and decreased C. neoformans-specific Th2 cells in the mediastinal lymph nodes. T1/ST2 deficiency also diminished goblet cell hyperplasia, mucus hypersecretion, bronchoalveolar lavage eosinophilia, alternative activation of macrophages, and serum IgE. These observations demonstrate that IL-33-dependent signaling contributes to the expansion of innate type 2 immunity and subsequent Th2-biased lung immunopathology that facilitates C. neoformans growth and dissemination.

STAT6 Controls the Number of Regulatory T Cells In Vivo, Thereby Regulating Allergic Lung Inflammation

STAT6 plays a central role in IL-4-mediated allergic responses. Several studies indicate that regulatory T cells (Tregs) can be modulated by IL-4 in vitro. We previously showed that STAT6(-/-) mice are highly resistant to allergic lung inflammation even when wild-type Th2 effectors were provided and that they have increased numbers of Tregs. However, the role of STAT6 in modulating Tregs in vivo during allergic lung inflammation has not been thoroughly investigated. To examine Treg and STAT6 interaction during allergic inflammation, STAT6(-/-), STAT6xRAG2(-/-), and RAG2(-/-) mice were subjected to OVA sensitization and challenge following adoptive transfer of OVA-specific, wild-type Th2 effectors with or without prior Treg depletion/inactivation, using anti-CD25 (PC61). As expected, STAT6(-/-) mice were highly resistant to airway inflammation and remodeling. In contrast, allergic lung inflammation was partially restored in STAT6(-/-) mice treated with PC61 to levels observed in STAT6xRAG2(-/-) mice. In some cases, STAT6xRAG2(-/-) mice were also given natural Tregs along with Th2 effectors. Adoptive transfer of natural Tregs caused a substantial reduction in bronchoalveolar lavage eosinophil composition and suppressed airway remodeling and T cell migration into the lung in STAT6xRAG2(-/-) mice to levels comparable to those in STAT6(-/-) mice. These results demonstrate the STAT6-dependent suppression of Tregs in vivo to promote allergic airway inflammation.