Identification of IL-5 and RANTES as the major eosinophil chemoattractants in the asthmatic lung

Eosinophilic inflammation: An Appealing Target for Pharmacologic Treatments in Severe Asthma

Severe asthma is characterized by different endotypes driven by complex pathologic mechanisms. In most patients with both allergic and non-allergic asthma, predominant eosinophilic airway inflammation is present. Given the central role of eosinophilic inflammation in the pathophysiology of most cases of severe asthma and considering that severe eosinophilic asthmatic patients respond partially or poorly to corticosteroids, in recent years, research has focused on the development of targeted anti-eosinophil biological therapies; this review will focus on the unique and particular biology of the eosinophil, as well as on the current knowledge about the pathobiology of eosinophilic inflammation in asthmatic airways. Finally, current and prospective anti-eosinophil therapeutic strategies will be discussed, examining the reason why eosinophilic inflammation represents an appealing target for the pharmacological treatment of patients with severe asthma.

Mouse pulmonary interstitial macrophages mediate the pro-tumorigenic effects of IL-9

Although IL-9 has potent anti-tumor activity in adoptive cell transfer therapy, some models suggest that it can promote tumor growth. Here, we show that IL-9 signaling is associated with poor outcomes in patients with various forms of lung cancer, and is required for lung tumor growth in multiple mouse models. CD4+ T cell-derived IL-9 promotes the expansion of both CD11c+ and CD11c- interstitial macrophage populations in lung tumor models. Mechanistically, the IL-9/macrophage axis requires arginase 1 (Arg1) to mediate tumor growth. Indeed, adoptive transfer of Arg1+ but not Arg1- lung macrophages to Il9r-/- mice promotes tumor growth. Moreover, targeting IL-9 signaling using macrophage-specific nanoparticles restricts lung tumor growth in mice. Lastly, elevated expression of IL-9R and Arg1 in tumor lesions is associated with poor prognosis in lung cancer patients. Thus, our study suggests the IL-9/macrophage/Arg1 axis is a potential therapeutic target for lung cancer therapy.

An IL-9-pulmonary macrophage axis defines the allergic lung inflammatory environment

Despite IL-9 functioning as a pleiotropic cytokine in mucosal environments, the IL-9-responsive cell repertoire is still not well defined. Here, we found that IL-9 mediates proallergic activities in the lungs by targeting lung macrophages. IL-9 inhibits alveolar macrophage expansion and promotes recruitment of monocytes that develop into CD11c+ and CD11c- interstitial macrophage populations. Interstitial macrophages were required for IL-9-dependent allergic responses. Mechanistically, IL-9 affected the function of lung macrophages by inducing Arg1 activity. Compared with Arg1-deficient lung macrophages, Arg1-expressing macrophages expressed greater amounts of CCL5. Adoptive transfer of Arg1+ lung macrophages but not Arg1- lung macrophages promoted allergic inflammation that Il9r-/- mice were protected against. In parallel, the elevated expression of IL-9, IL-9R, Arg1, and CCL5 was correlated with disease in patients with asthma. Thus, our study uncovers an IL-9/macrophage/Arg1 axis as a potential therapeutic target for allergic airway inflammation.

PI3Kδ inhibition prevents IL33, ILC2s and inflammatory eosinophils in persistent airway inflammation

Background

Phosphoinositide-3-kinase-delta (PI3Kδ) inhibition is a promising therapeutic approach for inflammatory conditions due to its role in leucocyte proliferation, migration and activation. However, the effect of PI3Kδ inhibition on group 2 innate lymphoid cells (ILC2s) and inflammatory eosinophils remains unknown. Using a murine model exhibiting persistent airway inflammation we sought to understand the effect of PI3Kδ inhibition, montelukast and anti-IL5 antibody treatment on IL33 expression, group-2-innate lymphoid cells, inflammatory eosinophils, and goblet cell metaplasia.

Results

Mice were sensitised to house dust mite and after allowing inflammation to resolve, were re-challenged with house dust mite to re-initiate airway inflammation. ILC2s were found to persist in the airways following house dust mite sensitisation and after re-challenge their numbers increased further along with accumulation of inflammatory eosinophils. In contrast to montelukast or anti-IL5 antibody treatment, PI3Kδ inhibition ablated IL33 expression and prevented group-2-innate lymphoid cell accumulation. Only PI3Kδ inhibition and IL5 neutralization reduced the infiltration of inflammatory eosinophils. Moreover, PI3Kδ inhibition reduced goblet cell metaplasia.

Conclusions

Hence, we show that PI3Kδ inhibition dampens allergic inflammatory responses by ablating key cell types and cytokines involved in T-helper-2-driven inflammatory responses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-021-00461-5.

Exosomes: A Key Piece in Asthmatic Inflammation

Asthma is a chronic disease of the airways that has an important inflammatory component. Multiple cells are implicated in asthma pathogenesis (lymphocytes, eosinophils, mast cells, basophils, neutrophils), releasing a wide variety of cytokines. These cells can exert their inflammatory functions throughout extracellular vesicles (EVs), which are small vesicles released by donor cells into the extracellular microenvironment that can be taken up by recipient cells. Depending on their size, EVs can be classified as microvesicles, exosomes, or apoptotic bodies. EVs are heterogeneous spherical structures secreted by almost all cell types. One of their main functions is to act as transporters of a wide range of molecules, such as proteins, lipids, and microRNAs (miRNAs), which are single-stranded RNAs of approximately 22 nucleotides in length. Therefore, exosomes could influence several physiological and pathological processes, including those involved in asthma. They can be detected in multiple cell types and biofluids, providing a wealth of information about the processes that take account in a pathological scenario. This review thus summarizes the most recent insights concerning the role of exosomes from different sources (several cell populations and biofluids) in one of the most prevalent respiratory diseases, asthma.

Role of Cytokines in EGPA and the Possibility of Treatment with an Anti-IL-5 Antibody

Eosinophilic granulomatosis with polyangiitis (EGPA) is a type of systemic vasculitis with eosinophilia in the peripheral blood, which is preceded by bronchial asthma or allergic disease. EGPA is pathologically characterized by microangiopathy granulomatosis vasculitis. Vasculitis can be exacerbated and cause central nervous system and cardiovascular disorders and gastrointestinal perforation. Histological examination reveals eosinophil infiltration and granulomas in lesions in areas such as the lung, nervous system, and skin. Laboratory tests show inflammatory findings such as C-reactive protein (CRP) elevation, increased eosinophils, elevated serum IgE, and elevated myeloperoxidase-anti-neutrophil cytoplasmic antibodies (MPO-ANCA). MPO-ANCA is positive in approximately 40-70% of cases of this disease. EGPA is a necrotizing vasculitis that affects small- and medium-sized blood vessels; however, it differs from other types of ANCA-related vasculitis (such as microscopic polyangiitis and granulomatosis) because it is preceded by bronchial asthma and eosinophilia in the blood and tissues. Treatment with immunosuppressive agents such as steroids or cyclophosphamide depends on the Five Factor Score, which predicts the prognosis and severity of the condition. If the effect of appropriate treatment with steroids is insufficient, the anti-interleukin-5 antibody mepolizumab can be administered. The combination of mepolizumab with standard treatment leads to a significantly longer duration of remission, a higher proportion of patients who achieve sustained remission, and less steroid use than with a placebo.

Association between Type 2 Diabetes, Obesity and Key Immunological Components of IgE-mediated Inflammation

BACKGROUND

Changes in lifestyle and obesity in recent decades have brought about a dramatic increase in type 2 diabetes mellitus (DM2) and allergic diseases. Clinical and epidemiological studies associate obesity with epidemics of allergic diseases. The link between obesity and DM2 with immunological components of IgE-mediated allergic inflammation is not yet conclusively established.

AIM

To examine the key immunological components of IgE-mediated allergic inflammation in patients with DM2 and their relationship with glycemic control and anthropometric indicators.

MATERIALS AND METHODS

Fifty-five patients with DM2 and 32 healthy controls with normal weight and body mass index (BMI) of 18-24.9 kg/m2 were included in the study. Th2-cytokine profile (serum levels of IL-4 and IL-5, pg/ml) and total serum IgE IU/ml were assessed in all participants in the study using ELISA. In patients with DM2, levels of glycated hemoglobin (HbA1c%) in the blood were also measured.

RESULTS

Serum levels of IL-4 and IL-5 are significantly higher in patients with DM2 compared to the control group. Serum levels of IL-4 and IL-5 positively correlated with BMI as well as serum levels of IL-4 with waist circumference. Total serum IgE positively correlated with HbA1c.

CONCLUSION

Obesity and poor glycemic control in patients with DM2 affect key immunological components of IgE-mediated allergic inflammation and possibly alter the immune response to allergens and antigens.

Type 2 immunity is protective in metabolic disease but exacerbates NAFLD collaboratively with TGF-β

Nonalcoholic fatty liver disease (NAFLD) is now the most common progressive liver disease in developed countries and is the second leading indication for liver transplantation due to the extensive fibrosis it causes. NAFLD progression is thought to be tied to chronic low-level type 1 inflammation originating in the adipose tissue during obesity; however, the specific immunological mechanisms regulating the progression of NAFLD-associated fibrosis in the liver are unclear. To investigate the immunopathogenesis of NAFLD more completely, we investigated adipose dysfunction, nonalcoholic steatohepatitis (NASH), and fibrosis in mice that develop polarized type 1 or type 2 immune responses. Unexpectedly, obese interleukin-10 (IL-10)/IL-4-deficient mice (type 1-polarized) were highly resistant to NASH. This protection was associated with an increased hepatic interferon-γ (IFN-γ) signature. Conversely, IFN-γ-deficient mice progressed rapidly to NASH with evidence of fibrosis dependent on transforming growth factor-β (TGF-β) and IL-13 signaling. Unlike increasing type 1 inflammation and the marked loss of eosinophils seen in expanding adipose tissue, progression of NASH was associated with increasing eosinophilic type 2 liver inflammation in mice and human patient biopsies. Finally, simultaneous inhibition of TGF-β and IL-13 signaling attenuated the fibrotic machinery more completely than TGF-β alone in NAFLD-associated fibrosis. Thus, although type 2 immunity maintains healthy metabolic signaling in adipose tissues, it exacerbates the progression of NAFLD collaboratively with TGF-β in the liver.

Serum Cytokine Profile in a Patient Diagnosed with Dysferlinopathy

Limb-girdle muscular dystrophy type 2 (LGMD2B) is a mild form of dysferlinopathy, characterized by limb weakness and wasting. It is an autosomal recessive disease, with currently 140 mutations in the LGMD2B gene identified. Lack of functional dysferlin inhibits muscle fiber regeneration in voluntary muscles, the main pathological finding in LGMD2B patients. However, the immune system has been suggested to contribute to muscle cell death and tissue regeneration. Serum levels of 27 cytokines were evaluated in a dysferlinopathy patient. Levels of 8 cytokines differed in patient serum compared to controls. Five cytokines (IL-10, IL-17, CCL2, CXCL10, and G-CSF) were higher while 3 were lower in the patient than in controls (IL-2, IL-8, and CCL11). Together, these data on serum cytokine profile of this dysferlinopathy patient suggest immune response activation, which could explain leukocyte infiltration in the muscle tissue.

Reduced pro-inflammatory responses to Staphylococcus aureus bloodstream infection and low prevalence of enterotoxin genes in isolates from patients on haemodialysis

Patients with end-stage renal failure undergo regular haemodialysis (HD) and often develop episodes of Staphylococcus aureus bloodstream infection (BSI), which can re-occur. However, clinically, patients on HD, with S. aureus BSI, respond well to treatment, rarely developing overt signs of sepsis. We investigated the contributions of bacterial virulence and cytokine responses to the clinical course of S. aureus BSI in HD and non-HD patients. Seventy patients were recruited, including 27 (38.6 %) patients on HD. Isolates were spa-typed and virulence and antimicrobial resistance gene carriage was investigated using DNA microarray analysis. Four inflammatory cytokines, IL-6, RANTES, GROγ and leptin, were measured in patient plasma on the day of diagnosis and after 7 days. There was no significant difference in the prevalence of genotypes or antimicrobial resistance genes in S. aureus isolates from HD compared to non-HD patients. The enterotoxin gene cluster (containing staphylococcal enterotoxins seg, sei, sem, sen, seo and seu) was significantly less prevalent among BSI isolates from HD patients compared to non-HD patients. Comparing inflammatory cytokine response to S. aureus BSI in HD patients to non-HD patients, IL-6 and GROγ were significantly lower (p = 0.021 and p = 0.001, respectively) in HD patients compared to other patients on the day of diagnosis and RANTES levels were significantly lower (p = 0.025) in HD patients on day 7 following diagnosis. Lowered cytokine responses in HD patients and a reduced potential for super-antigen production by infecting isolates may partly explain the favourable clinical responses to episodes of S. aureus BSI in HD patients that we noted clinically.

PLAG (1-Palmitoyl-2-Linoleoyl-3-Acetyl-rac-Glycerol) Modulates Eosinophil Chemotaxis by Regulating CCL26 Expression from Epithelial Cells

Increased number of eosinophils in the circulation and sputum is associated with the severity of asthma. The respiratory epithelium produces chemokine (C-C motif) ligands (CCL) which recruits and activates eosinophils. A chemically synthesized monoacetyl-diglyceride, PLAG (1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol) is a major constituent in the antlers of Sika deer (Cervus nippon Temminck) which has been used in oriental medicine. This study was aimed to investigate the molecular mechanism of PLAG effect on the alleviation of asthma phenotypes. A549, a human alveolar basal epithelial cell, and HaCaT, a human keratinocyte, were activated by the treatment of interleukin-4 (IL-4), and the expression of chemokines, known to be effective on the induction of eosinophil migration was analyzed by RT-PCR. The expression of IL-4 induced genes was modulated by the co-treatment of PLAG. Especially, CCL26 expression from the stimulated epithelial cells was significantly blocked by PLAG, which was confirmed by ELISA. The transcriptional activity of signal transducer and activator of transcription 6 (STAT6), activated by IL-4 mediated phosphorylation and nuclear translocation, was down-regulated by PLAG in a concentration-dependent manner. In ovalbumin-induced mouse model, the infiltration of immune cells into the respiratory tract was decreased by PLAG administration. Cytological analysis of the isolated bronchoalveolar lavage fluid (BALF) cells proved the infiltration of eosinophils was significantly reduced by PLAG. In addition, PLAG inhibited the migration of murine bone marrow-derived eosinophils, and human eosinophil cell line, EoL-1, which was induced by the addition of A549 culture medium.

Pulmonary CD103 expression regulates airway inflammation in asthma

Although CD103(+) cells recently emerged as key regulatory cells in the gut, the role of CD103 ubiquitous expression in the lung and development of allergic airway disease has never been studied. To answer this important question, we evaluated the response of Cd103(-/-) mice in two separate well-described mouse models of asthma (ovalbumin and house dust mite extract). Pulmonary inflammation was assessed by analysis of bronchoalveolar lavage content, histology, and cytokine response. CD103 expression was analyzed on lung dendritic cells and T cell subsets by flow cytometry. Cd103(-/-) mice exposed to antigens developed exacerbated lung inflammation, characterized by increased eosinophilic infiltration, severe tissue inflammation, and altered cytokine response. In wild-type mice exposed to house dust mite, CD103(+) dendritic cells are increased in the lung and an important subset of CD4(+) T cells, CD8(+) T cells, and T regulatory cells express CD103. Importantly, Cd103(-/-) mice presented a deficiency in the resolution phase of inflammation, which supports an important role for this molecule in the control of inflammation severity. These results suggest an important role for CD103 in the control of airway inflammation in asthma.

Food allergy enhances allergic asthma in mice

Background

Atopic march refers to the typical transition from a food allergy in early childhood to allergic asthma in older children and adults. However the precise interplay of events involving gut, skin and pulmonary inflammation in this process is not completely understood.

Objectives

To develop a mouse model of mixed food and respiratory allergy mimicking the atopic march and better understand the impact of food allergies on asthma.

Methods

Food allergy to ovalbumin (OVA) was induced through intra-peritoneal sensitization and intra-gastric challenge, and/or a respiratory allergy to house dust mite (HDM) was obtained through percutaneous sensitization and intra-nasal challenges with dermatophagoides farinae (Der f) extract. Digestive, respiratory and systemic parameters were analyzed.

Results

OVA-mediated gut allergy was associated with an increase in jejunum permeability, and a worsening of Der f-induced asthma with stronger airway hyperresponsiveness and pulmonary cell infiltration, notably eosinophils. There was overproduction of the pro-eosinophil chemokine RANTES in broncho-alveolar lavages associated with an enhanced Th2 cytokine secretion and increased total and Der f-specific IgE when the two allergies were present. Both AHR and lung inflammation increased after a second pulmonary challenge.

Conclusion

Gut sensitization to OVA amplifies Der f-induced asthma in mice.

Cytokine responses to Staphylococcus aureus bloodstream infection differ between patient cohorts that have different clinical courses of infection

Background

The clinical course of Staphylococcus aureus bloodstream infection is unpredictable and bacterial virulence, host immune response and patient characteristics are among the factors that contribute to the clinical course of infection. To investigate the relationship between cytokine response and clinical outcome, circulating cytokine levels were investigated in response to S. aureus bloodstream infection in patients with different clinical courses of infection.

Methods

A prospective study was carried out in 61 patients with S. aureus bloodstream infection and circulating levels of IL-6, GRO-γ, RANTES and leptin were assessed over the course of the infection. Levels were compared in patients with complicated courses of infection (e.g. infective endocarditis) versus uncomplicated courses of S. aureus bloodstream infection and methicillin-resistant S. aureus Vs methicillin-susceptible S. aureus infection.

Results

Significantly lower leptin levels (p < 0.05) and significantly higher IL-6 levels (p < 0.05) were detected at laboratory diagnosis in patients with complicated compared to uncomplicated S. aureus bloodstream infection. Significantly higher levels of GRO-γ were associated with MRSA infection compared to MSSA infection.

Conclusions

IL-6 may be an early inflammatory marker of complicated S. aureus bloodstream infection. Leptin may be protective against the development of a complicated S. aureus bloodstream infection.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0580-6) contains supplementary material, which is available to authorized users.

Cytokines and chemokines: At the crossroads of cell signalling and inflammatory disease

Inflammation occurs as a result of exposure of tissues and organs to harmful stimuli such as microbial pathogens, irritants, or toxic cellular components. The primary physical manifestations of inflammation are redness, swelling, heat, pain, and loss of function to the affected area. These processes involve the major cells of the immune system, including monocytes, macrophages, neutrophils, basophils, dendritic cells, mast cells, T-cells, and B-cells. However, examination of a range of inflammatory lesions demonstrates the presence of specific leukocytes in any given lesion. That is, the inflammatory process is regulated in such a way as to ensure that the appropriate leukocytes are recruited. These events are in turn controlled by a host of extracellular molecular regulators, including members of the cytokine and chemokine families that mediate both immune cell recruitment and complex intracellular signalling control mechanisms that characterise inflammation. This review will focus on the role of the main cytokines, chemokines, and their receptors in the pathophysiology of auto-inflammatory disorders, pro-inflammatory disorders, and neurological disorders involving inflammation.

Autotaxin and lysophosphatidic acid signalling in lung pathophysiology

Autotaxin (ATX or ENPP2) is a secreted glycoprotein widely present in biological fluids. ATX primarily functions as a plasma lysophospholipase D and is largely responsible for the bulk of lysophosphatidic acid (LPA) production in the plasma and at inflamed and/or malignant sites. LPA is a phospholipid mediator produced in various conditions both in cells and in biological fluids, and it evokes growth-factor-like responses, including cell growth, survival, differentiation and motility, in almost all cell types. The large variety of LPA effector functions is attributed to at least six G-protein coupled LPA receptors (LPARs) with overlapping specificities and widespread distribution. Increased ATX/LPA/LPAR levels have been detected in a large variety of cancers and transformed cell lines, as well as in non-malignant inflamed tissues, suggesting a possible involvement of ATX in chronic inflammatory disorders and cancer. In this review, we focus exclusively on the role of the ATX/LPA axis in pulmonary pathophysiology, analysing the effects of ATX/LPA on pulmonary cells and leukocytes in vitro and in the context of pulmonary pathophysiological situations in vivo and in human diseases.

Changes of histamine receptors and CC chemokines in nasal epithelial cells and fibroblasts after respiratory syncytial virus infection

BACKGROUND

Respiratory syncytial virus (RSV) is reported as the most influential factor that triggers hyperreactivity of the airway and causes asthma in infants and children. However, the mechanisms remain to be elucidated. The study evaluated the changes in the levels of four types of histamine receptor (HR) and CC chemokines, such as eotaxin and regulated on activation, normal T cell expressed and presumably secreted (RANTES), in nasal epithelial cells and fibroblasts after RSV infection.

METHODS

Nasal cavity mucosa attained from 20 patients who had undergone inferior turbinoplasty were cleaned by normal saline mixed with gentamicin. Each sample was divided in half. One-half was used for incubation of epithelial cells, and the other half was used for culturing fibroblasts. The levels of HR 1 (H1R), 2 (H2R), 3 (H3R), 4 (H4R), eotaxin, and RANTES were measured by real-time polymerase chain reaction 0, 12, and 36 hours after infection with RSV.

RESULTS

H1R was significantly increased at 12 and 36 hours compared with 0 hours in both cell types. The level of H2R was significantly increased in epithelial cells from 0 to 36 and 12 to 36 hours and in fibroblasts from 0 to 12 and 0 to 36 hours. There were significant increases of H3R level in fibroblasts from 0 to 12 and 0 to 36 hours, and of H4R in epithelial cells and fibroblasts from 0 to 12 and 0 to 36 hours. Eotaxin and RANTES were also significantly increased in both epithelial cells and fibroblasts from 0 to 12 and 0 to 36 hours.

CONCLUSION

RSV infection increases the levels of all four HRs, especially H1R and H2R, as well as the levels of eotaxin and RANTES in nasal epithelial cells and fibroblasts. These findings suggest that RSV infection might cause respiratory tract hyperreactivity by increasing the content of HRs and CC chemokines.

Influenza enhances caspase-1 in bronchial epithelial cells from asthmatic volunteers and is associated with pathogenesis

BACKGROUND

The leading cause of asthma exacerbation is respiratory viral infection. Innate antiviral defense pathways are altered in the asthmatic epithelium, yet involvement of inflammasome signaling in virus-induced asthma exacerbation is not known.

OBJECTIVE

This study compared influenza-induced activation of inflammasome and innate immune signaling in human bronchial epithelial cells from volunteers with and without asthma and investigated the role of caspase-1 in epithelial cell antiviral defense.

METHODS

Differentiated primary human bronchial epithelial cells from volunteers with and without asthma were infected with influenza A virus. An inflammasome-specific quantitative real-time polymerase chain reaction array was used to compare baseline and influenza-induced gene expression profiles. Cytokine secretion, innate immune gene expression, and viral replication were compared between human bronchial epithelial cells from volunteers with and without asthma. Immunofluorescence microscopy was used to evaluate caspase-1 and PYCARD colocalization. Tracheal epithelial cells from caspase-1-deficient or wild-type mice were infected with influenza and assessed for antiviral gene expression and viral replication.

RESULTS

Human bronchial epithelial cells from asthmatic volunteers had altered influenza-induced expression of inflammasome-related and innate immune signaling components, which correlated with enhanced production of IL-1β, IL-6, and TNF-α. Specifically, influenza-induced caspase-1 expression was enhanced and localization differed in human bronchial epithelial cells from asthmatic volunteers compared to volunteers without asthma. Influenza-infected tracheal epithelial cells from caspase-1-deficient mice had reduced expression of antiviral genes and viral replication.

CONCLUSION

Caspase-1 plays an important role in the airway epithelial cell response to influenza infection, which is enhanced in asthmatic volunteers, and may contribute to the enhanced influenza-related pathogenesis observed in vivo.

Clarithromycin suppresses human respiratory syncytial virus infection-induced Streptococcus pneumoniae adhesion and cytokine production in a pulmonary epithelial cell line

Human respiratory syncytial virus (RSV) sometimes causes acute and severe lower respiratory tract illness in infants and young children. RSV strongly upregulates proinflammatory cytokines and the platelet-activating factor (PAF) receptor, which is a receptor for Streptococcus pneumoniae, in the pulmonary epithelial cell line A549. Clarithromycin (CAM), which is an antimicrobial agent and is also known as an immunomodulator, significantly suppressed RSV-induced production of interleukin-6, interleukin-8, and regulated on activation, normal T-cell expressed and secreted (RANTES). CAM also suppressed RSV-induced PAF receptor expression and adhesion of fluorescein-labeled S. pneumoniae cells to A549 cells. The RSV-induced S. pneumoniae adhesion was thought to be mediated by the host cell's PAF receptor. CAM, which exhibits antimicrobial and immunomodulatory activities, was found in this study to suppress the RSV-induced adhesion of respiratory disease-causing bacteria, S. pneumoniae, to host cells. Thus, CAM might suppress immunological disorders and prevent secondary bacterial infections during RSV infection.

TLR3 but not TLR7/8 ligand induces allergic sensitization to inhaled allergen

Epidemiological studies suggest that viral infections during childhood are a risk factor for the development of asthma. However, the role of virus-specific pattern recognition receptors in this process is not well defined. In the current study, we compare the effects of the inhaled viral TLR ligands polyinosinic-polycytidylic acid (TLR3) and resiquimod (TLR7/8) on sensitization to a model allergen (OVA) in a murine model. Both compounds enhance the migration, activation, and Ag-processing of myeloid dendritic cells from the lung to the draining lymph nodes comparable to the effects of LPS. Application of polyinosinic-polycytidylic acid [poly(I:C)] or LPS induces production of allergen-specific IgE and IgG1, whereas resiquimod (R848) had no effect. In addition, rechallenge of mice with OVA resulted in airway inflammation and mucus production in animals that received either poly(I:C) or LPS but not after application of R848. In summary, these results show that activation of TLR3 in combination with inhaled allergen results in induction of dendritic cell activation and migration similar to the effects of LPS. This leads to the development of allergic airway disease after allergen rechallenge, whereas mice treated with R848 did not develop allergic airway disease. These findings give further insight into the effects of stimulation of different TLRs on the development of asthma.

Epithelial cells and airway diseases

The airway epithelial cell is the initial cell type impacted both by inhaled environmental factors, such as pathogens, allergens, and pollutants, and inhaled medications for airway diseases. As such, epithelial cells are now recognized to play a central role in the regulation of airway inflammatory status, structure, and function in normal and diseased airways. This article reviews our current knowledge regarding the roles of the epithelial cell in airway inflammation and host defense. The interactions of inhaled environmental factors and pathogens with epithelial cells are also discussed, with an emphasis on epithelial innate immune responses and contributions of epithelial cells to immune regulation. Recent evidence suggesting that epithelial cells play an active role in inducing several of the structural changes, collectively referred to airway remodeling, seen in the airways of asthmatic subjects is reviewed. Finally, the concept that the epithelium is a major target for the actions of a number of classes of inhaled medications is discussed, as are the potential mechanisms by which selected drugs may alter epithelial function.

Type-III interferon, not type-I, is the predominant interferon induced by respiratory viruses in nasal epithelial cells

As an innate immune response against diverse viral infections, a host induces two types of interferon (IFN), type-I (IFN-β/α) and type-III (IFN-λ). We investigated IFN inductions by respiratory viruses, including respiratory syncytial virus (RSV), measles virus and mumps virus in human nasal epithelial cells (NECs). IFN-λ, but not IFN-β/α, was induced by respiratory virus infection in primary NECs and immortalized NECs through transfection with the human telomerase reverse transcriptase gene (hTERT-NECs). In contrast, both IFN-λ and IFN-β/α were induced by RSV infection in human bronchiolar carcinoma cell line A549. Suppression of retinoic acid-inducible gene-I (RIG-I) expression using siRNA significantly reduced IFN-λ1 production in RSV-infected hTERT-NECs, while suppression of melanoma differentiation-associated gene 5 (MDA5) expression did not. Exogenous IFN-λ1 treatment suppressed RSV replication and chemokine induction in hTERT-NECs. These data indicate that IFN-λ, but not IFN-β/α, contributes to the main first line defense via RIG-I-dependent pathway against respiratory virus infection in NECs.

SOCS2 regulates T helper type 2 differentiation and the generation of type 2 allergic responses

The incidence of allergy and asthma in developed countries is on the increase and this trend looks likely to continue. CD4(+) T helper 2 (Th2) cells are major drivers of these diseases and their commitment is controlled by cytokines such as interleukin 4, which are in turn regulated by the suppressor of cytokine signaling (SOCS) proteins. We report that SOCS2(-/-) CD4(+) T cells show markedly enhanced Th2 differentiation. SOCS2(-/-) mice, as well as RAG-1(-/-) mice transferred with SOCS2(-/-) CD4(+) T cells, exhibit elevated type 2 responses after helminth antigen challenge. Moreover, in in vivo models of atopic dermatitis and allergen-induced airway inflammation, SOCS2(-/-) mice show significantly elevated IgE, eosinophilia, type 2 responses, and inflammatory pathology relative to wild-type mice. Finally, after T cell activation, markedly enhanced STAT6 and STAT5 phosphorylation is observed in SOCS2(-/-) T cells, whereas STAT3 phosphorylation is blunted. Thus, we provide the first evidence that SOCS2 plays an important role in regulating Th2 cell expansion and development of the type 2 allergic responses.

Key role of water-insoluble allergens of pollen cytoplasmic granules in biased allergic response in a rat model

BACKGROUND

: Grass pollen grain, an important aeroallergen, can disperse in the environment pollen cytoplasmic granules (PCGs) able to release water-soluble allergens when they are washed out by rainfall. The allergenicity of these washed PCGs is, however, preserved.

OBJECTIVE

: The purpose of the study was to assess the allergenic potential of washed and unwashed PCGs, from Phleum pratense pollen grains, in the Brown Norway rat, and to study the IgE reactivity of sera of sensitized rats to water-soluble and water-insoluble extracts of PCGs and pollen grains.

METHODS

: Rats were sensitized and challenged intratracheally with washed or unwashed PCGs or pollen grains. Using water-soluble and -insoluble extracts of pollen grains and/or PCGs, IgE ELISA and immunoblotting were performed with rat sera. Proliferation of bronchial lymph node cells was monitored by [H]-thymidine incorporation in a lymph node assay. Alveolar cells, proteins, and TH1 and TH2 cytokines were quantified in bronchoalveolar lavage fluid.

RESULTS

: Rats sensitized with unwashed PCGs showed a predominant humoral response with high serum IgE and reactivity to water-soluble and -insoluble proteins together with low lymph node cell proliferation. Conversely, in rats sensitized to washed PCGs, cellular responses were higher with significant increases in eosinophils, lymphocytes, and TH2 cytokines observed in bronchoalveolar lavage fluid.

CONCLUSION

: Allergic and inflammatory responses were induced by both grass pollen grains and their isolated washed and unwashed PCGs. However, on the basis of humoral and cellular responses, differential patterns were observed. Water-insoluble allergens seem to play a role in the centrally mediated inflammatory response, whereas water-soluble allergens may be involved in the peripheral humoral response.

Functional genomics of human bronchial epithelial cells directly interacting with conidia of Aspergillus fumigatus

Background

Aspergillus fumigatus (A. fumigatus) is a ubiquitous fungus which reproduces asexually by releasing abundant airborne conidia (spores), which are easily respirable. In allergic and immunocompromised individuals A. fumigatus can cause a wide spectrum of diseases, including allergic bronchopulmonary aspergillosis, aspergilloma and invasive aspergillosis. Previous studies have demonstrated that A. fumigatus conidia are internalized by macrophages and lung epithelial cells; however the exact transcriptional responses of airway epithelial cells to conidia are currently unknown. Thus, the aim of this study was to determine the transcriptomic response of the human bronchial epithelial cell line (16HBE14o-) following interaction with A. fumigatus conidia. We used fluorescence-activated cell sorting (FACS) to separate 16HBE14o- cells having bound and/or internalized A. fumigatus conidia expressing green fluorescent protein from cells without spores. Total RNA was then isolated and the transcriptome of 16HBE14o- cells was evaluated using Agilent Whole Human Genome microarrays.

Results

Immunofluorescent staining and nystatin protection assays demonstrated that 16HBE14o- cells internalized 30-50% of bound conidia within six hrs of co-incubation. After FAC-sorting of the same cell culture to separate cells associated with conidia from those without conidia, genome-wide analysis revealed a set of 889 genes showing differential expression in cells with conidia. Specifically, these 16HBE14o- cells had increased levels of transcripts from genes associated with repair and inflammatory processes (e.g., matrix metalloproteinases, chemokines, and glutathione S-transferase). In addition, the differentially expressed genes were significantly enriched for Gene Ontology terms including: chromatin assembly, G-protein-coupled receptor binding, chemokine activity, and glutathione metabolic process (up-regulated); cell cycle phase, mitosis, and intracellular organelle (down-regulated).

Conclusions

We demonstrate a methodology using FACs for analyzing the transcriptome of infected and uninfected cells from the same cell population that will provide a framework for future characterization of the specific interactions between pathogens such as A. fumigatus with human cells derived from individuals with or without underlying disease susceptibility.

Immunologic messenger molecules: cytokines, interferons, and chemokines

Cytokines and chemokines are secreted proteins involved in numerous aspects of cell growth, differentiation, and activation. A prominent feature of these molecules is their effect on the immune system with regard to cell trafficking and development of immune tissue and organs. The nature of an immune response determines which cytokines are produced and ultimately whether the response is cytotoxic, humoral, cell mediated, or allergic. For this chapter, cytokines are grouped according to those that are predominantly antigen-presenting cell or T lymphocyte derived; that mediate cytotoxic, humoral, cell mediated, and allergic immunity; or that are immunosuppressive. A discussion of chemokine function and their role in cell trafficking and disease follows.

Asthma during pregnancy alters immune cell profile and airway epithelial chemokine release

OBJECTIVE

Pregnancy can influence the course of maternal asthma, but the mechanisms are presently unknown. The aim of the present study was to access maternal immune cell profiles in the presence and absence of asthma and to determine the effect of pregnancy-derived factors on epithelial cell function.

METHODS

Cells from the human bronchial epithelial cell line BEAS-2B were treated with plasma from pregnant or nonpregnant asthmatic and nonasthmatic subjects. Cell culture supernatants were collected after 24 h and assayed for IL-6, IL-8, eotaxin, RANTES and sICAM-1 protein using ELISA. Maternal immune cell count and peripheral blood chemotactic response to plasma from pregnant and non-pregnant asthmatic subjects were also assessed.

RESULTS

The presence of maternal asthma during pregnancy was associated with increased monocyte and neutrophil numbers, increased BEAS-2B cell production of IL-8 and sICAM-1 (P < 0.05) and increased chemotactic capacity relative to pregnant women without asthma.

CONCLUSION

The results of this study suggest that circulating pregnancy-related factors enhance chemotactic mediators in epithelial cells in the presence of asthma. This may be one mechanism that contributes to pregnancy-induced changes in asthma.

Immunological Interactive Effects between Pollen Grains and Their Cytoplasmic Granules on Brown Norway Rats

BACKGROUND

: Grass pollen is one of the most important aeroallergen vectors in Europe. Under some meteorological factors, pollen grains can release pollen cytoplasmic granules (PCGs). PCGs induce allergic responses. Several studies have shown that during a period of thunderstorms the number of patients with asthma increases because of higher airborne concentrations of PCGs.

OBJECTIVE

: The aims of the study were to assess the allergenicity of interactive effects between pollen and PCGs and to compare it with allergenicity of Timothy grass pollen and PCGs in Brown Norway rats.

METHODS

: Rats were sensitized (day 0) and challenged (day 21) with pollen grains and/or PCGs. Four groups were studied: pollen-pollen (PP), PCGs-PCGs (GG), pollen-PCGs (PG), and PCGs-pollen (GP). Blood samples, bronchoalveolar lavage fluid, and bronchial lymph node were collected at day 25. IgE and IgG1 levels in sera were assessed by enzyme-linked immunosorbent assay. Alveolar cells, protein, and cytokine concentrations were quantified in bronchoalveolar lavage fluid. T-cell proliferation, in response to pollen or granules, was performed by lymph node assay.

RESULTS

: Interactive effects between pollen and PCGs increased IgE and IgG1 levels when compared with those of the negative control. These increases were lower than those of the PP group but similar to the levels obtained by the GG group. Whatever was used in the sensitization and/or challenge phase, PCGs increased lymphocyte and Rantes levels compared with those of the pollen group. The interactive effects increased IL-1α and IL-1β compared with those of the PP and GG groups.

CONCLUSIONS

: Immunologic interactive effects have been shown between pollen and PCGs. For humoral and cellular allergic responses, interactive effects between the 2 aeroallergenic sources used in this study seem to be influenced mainly by PCGs.

IL-6 is required for airway mucus production induced by inhaled fungal allergens

Allergic asthma is caused by inhaled allergens and is characterized by airway eosinophilia, as well as mucus hypersecretion, which can lead to airflow obstruction. Despite the association of increased IL-6 levels with human atopic asthma, the contribution of IL-6 to the development of allergic airway inflammation triggered by inhaled allergens remains unclear. In this study, we examined the role of IL-6 in a mouse model of allergic airway inflammation induced by direct airway exposure to extracts of Aspergillus fumigatus, a common allergen in humans. We show that inhaled A. fumigatus extracts rapidly trigger the production of IL-6 in the airways. IL-6 appears to be dispensable for the recruitment of eosinophils to the lung during the development of allergic airway inflammation. However, IL-6 is essential for mucus hypersecretion by airway epithelial cells triggered in response to inhaled A. fumigatus Ags. Impaired mucus production caused by IL-6 deficiency correlates with a severe reduction in the levels of IL-13, a major inducer of mucin glycoproteins. Thus, IL-6 is a key regulator of specific hallmark features of allergic airway inflammation and it could be a potential target for pulmonary diseases that are associated with goblet cell metaplasia and mucus hypersecretion.

Fosfomycin suppresses chemokine induction in airway epithelial cells infected with respiratory syncytial virus

Respiratory syncytial virus (RSV) infects airway epithelial cells, causing bronchiolitis and pneumonia. Inflammation is mediated by various cytokines secreted from RSV-infected airway epithelial cells, and it promotes the pathogenesis of RSV-related diseases. Fosfomycin (FOF) is approved as a treatment for various bacterial infectious diseases, including respiratory infectious diseases, in Japan. FOF is suggested to exhibit immunomodulatory effects on lipopolysaccharide-stimulated monocytes and T lymphocytes, in addition to its antimicrobial activity. We investigated the effect of FOF on the cytokine production of an airway epithelial cell line, A549, infected with RSV. RSV-induced cytokines, such as regulated on activation, normal T-cell expressed and secreted (RANTES), interleukin-8 (IL-8), and IL-6, in infected A549 cells. We found that FOF decreased the levels of RSV-induced RANTES and IL-8 but not the level of RSV-induced IL-6. The RANTES promoter was activated by RSV infection. Site-directed mutagenesis analysis of the RANTES promoter showed that NF-kappaB-binding motifs had a critical role in RSV-induced RANTES promoter activity. A luciferase reporter gene assay and a DNA-binding assay indicated that FOF suppressed the NF-kappaB activity induced by RSV infection. These results demonstrate that FOF treatment suppresses the RSV-induced transcription of the chemokines RANTES and IL-8 in airway epithelial cells.

RANTES gene promoter polymorphisms are associated with bronchial hyperresponsiveness in Korean children with asthma

Regulated upon activation in normal T cells, expressed, and secreted (RANTES) protein is abundantly expressed during atopic asthma, suggesting that it is an important mediator of this disease. The aim of this study was to evaluate the possible role of RANTES promoter polymorphisms in children with asthma. We genotyped 271 children with atopic asthma, 55 children with nonatopic asthma, and 253 control children for allelic determinants at two polymorphic sites in the promoter region at positions -403G>A and -28C>G by restriction fragment length polymorphism methods. There was no significant difference in genotype and allele frequencies of the RANTES -403G>A and -28C>G polymorphisms when the atopic asthma, nonatopic asthma, and control groups were compared. However, atopic asthmatic patients who were homozygous GG for the RANTES -28C>G tended to have lower PC20 methacholine than those carrying the wild genotype. In addition, a significantly lower PC20 was demonstrated for the homozygous haplotype -403A/-28G in asthmatic children. The polymorphisms within the RANTES promoter may have a disease-modifying effect in Korean children with asthma.

Relationship between airway reactivity induced by methacholine or ultrasonically nebulized distilled cold water and BAL fluid cellular constituents in patients with sulfur mustard gas-induced asthma

The objective of this article was to evaluate the relationship between the bronchial reactivity to methacholine and distilled cold water and inflammatory bronchial alveolar lavage (BAL) cells in mustard gas-induced asthma. This was a randomized, crossover clinical study set in a university hospital. The patients were 17 veterans with mustard gas-induced asthma and 17 normal veterans as a control group. Inhalation challenges with ultrasonically nebulized distilled water and methacholine and BAL via bronchoscopy and were performed in all patients and subjects. All patients did sustain a 20% fall in FEV(1) after methacholine, whereas two of them did not with distilled cold water. The patients were sensitive to distilled cold water with a median PD20 of 8.44 +/- 6.55 mL and sensitive to methacholine with the median PC20 of 4.88 +/- 4.22 mg/mL. Significant correlation was found between PC20 of methacholine and PD20 of distilled cold water (r = -0.74, p = 0.005). The proportion of BAL macrophages was significantly lower in patients with asthma than in the control group (p = 0.001). The proportions of lymphocytes and neutrophils were similar in the two groups. The percentage of eosinophils was higher in BAL fluid from the asthmatics compared with that in BAL fluid from the control group (p < 0.001). The percentage of the BAL eosinophils significantly correlated with both PC20 of methacholine (r = - 0.58, p = 0.01) and PD20 of distilled cold water (r = -0.81, p = 0.002). No relationship between PC20 of methacholine or PD20 of distilled cold water was found for other inflammatory BAL cells. This study showed that in patients with mustard gas-induced asthma, the degree of airway responsiveness to both methacholine and distilled water was associated with the percentage of BAL eosinophils.

IL-10 and RANTES are elevated in nasopharyngeal secretions of children with respiratory syncytial virus infection

BACKGROUND

Respiratory syncytial virus (RSV) infection causes asthma-like symptoms in infants and young children. Although an increase in several mediators in the airway during RSV infection has been reported, the mechanisms involved in airway inflammation are not fully understood. The aim of this study was to investigate the immunological deviation associated with airway inflammation by measuring cytokine and chemokine levels in the airway during RSV infection.

METHODS

One hundred and ten children under 3 years of age with respiratory symptoms were enrolled in this study from November 2004 through January 2005. Nasopharyngeal secretions (NPAs) were gently aspirated and analyzed with RSV antigen, thereafter the concentrations of IL-4, IL-10, IFN-gamma, and RANTES were measured using an ELISA kit. We also investigated the prognosis of each child after 1 year by reference to clinical records or by interviews and re-evaluated the cytokine and chemokine levels.

RESULTS

Of the subjects, 70 children were RSV positive and 40 were negative. Only 4 children were given a diagnosis of asthma by the pediatrician when NPAs were collected. The levels of IL-4, IL-10, and RANTES were significantly higher in the RSV-positive patients than RSV-negative patients with P values at 0.0362, 0.0007, and 0.0047, respectively. In contrast, there was no significant difference in the levels of IFN-gamma. Furthermore, there was a significant positive correlation between IL-10 and RANTES.

CONCLUSIONS

The increased production of IL-4, IL-10, and RANTES in the airway may play an important role in the pathophysiological mechanisms of RSV infection.

Cytokine induction by respiratory syncytial virus and adenovirus in bronchial epithelial cells

In order to broaden our knowledge of the primary immune responses to respiratory syncytial virus (RSV) and adenovirus infections, we compared the concentrations of interleukin (IL)-6, IL-8, and regulated on activation, normal T cell expressed and secreted (RANTES) produced in vitro during RSV and adenovirus infections of bronchial epithelial cells. We infected BEAS-2B cells-a human bronchial epithelial cell line-with RSV, adenovirus serotype 3, or serotype 7 and measured the concentrations of IL-6, IL-8, and RANTES in the cell culture supernatants. When the multiplicity of infection (MOI) was 1, RSV induced the production of markedly higher concentrations of IL-6, IL-8, and RANTES than the adenovirus. When the MOI of the adenovirus was increased to 100, the production of IL-6 and IL-8 increased. However, the amounts produced were still lower than those produced by RSV with the MOI of 1. There was no statistically significant increase in the production of RANTES in spite of the MOI of the adenovirus was increased to 100. Adenovirus serotype 7 induced the production of considerably more IL-6 and IL-8 than serotype 3 in the MOI of 100. However, neither adenovirus serotype triggered an increase in the production of RANTES in spite of the MOI of 100. This demonstrates that RSV could have a superior capacity to stimulate the production of IL-6, IL-8, and RANTES in the bronchial epithelial cells. This study may help to explain the differences in the clinical outcomes of RSV and adenovirus infections.

IL-1 beta stimulates divergent upper and lower airway epithelial cell CCL5 secretion

Direct infection of respiratory epithelium induces chemokine secretion and upregulates cytokine networks, which are central in regulating inflammation. IL-1beta may have a pivotal role in such networks. Differential control of chemokine secretion within specific airway regions, which have distinct roles in immunity, is not well characterized. We investigated IL-1beta-induced CXCL8 and CCL5 secretion from primary normal human bronchial and small airway epithelial cells, and the alveolar cell line A549. CXCL8 was secreted by all cells, but only lower airway cells secreted CCL5. IL-1beta induced nuclear translocation of NF-kappaB (p50, p65 and c-Rel subunits), NF-IL-6 and AP-1, each with distinct kinetics. This was associated with high level CCL5 promoter activation, via transcription factor binding to multiple regions, including NF-kappaB, AP-1 and NF-IL-6 sites. The IL-1-related cytokine IL-18 did not drive or modulate IL-1beta-induced CXCL8 or CCL5 secretion. In summary, IL-1beta, but not IL-18, induces transcription-dependent lower airway epithelial cell-specific CCL5 secretion. Differential chemokine secretion may have profound effects on local leukocyte influx within upper or lower airways exposed to airway infection or environmental stimuli, which might then require different anti-inflammatory strategies.

Computer prediction of allergen proteins from sequence-derived protein structural and physicochemical properties

BACKGROUND

Computational methods have been developed for predicting allergen proteins from sequence segments that show identity, homology, or motif match to a known allergen. These methods achieve good prediction accuracies, but are less effective for novel proteins with no similarity to any known allergen.

METHODS

This work tests the feasibility of using a statistical learning method, support vector machines, as such a method. The prediction system is trained and tested by using 1005 allergen proteins from the Allergome database and 22,469 non-allergen proteins from 7871 Pfam families.

RESULTS

Testing results by an independent set of 229 allergen and 6717 non-allergen proteins from 7871 Pfam families show that 93.0% and 99.9% of these are correctly predicted, which are comparable to the best results of other methods. Of the 18 novel allergen proteins non-homologous to any other proteins in the Swissprot database, 88.9% is correctly predicted. A further screening of 168,128 proteins in the Swissprot database finds that 2.9% of the proteins are predicted as allergen proteins, which is consistent with the estimated numbers from motif-based methods.

CONCLUSIONS

Our study suggests that SVM is a potentially useful method for predicting allergen proteins and it has certain capability for predicting novel allergen proteins. Our software can be accessed at .

Role of structural cells of the cornea and conjunctiva in the pathogenesis of vernal keratoconjunctivitis

Vernal keratoconjunctivitis (VKC) is a severe type of allergic conjunctival disease characterized by the presence both of various corneal epithelial and stromal lesions as well as of conjunctival proliferative changes such as giant papillae of the upper tarsal conjunctiva and limbal lesions. These clinical findings as well as various pathophysiological characteristics of VKC are distinct from those of other types of ocular allergy and allergic diseases of other organs. The outer eye possesses specific allergological characteristics, one of which is communication between the cornea and conjunctiva through a thin layer of tear fluid. Fibroblasts of the cornea and the conjunctiva are activated by proinflammatory and T helper 2 (Th2) cell-derived cytokines. Corneal fibroblasts enhance ocular allergic reactions as a result of their activation-induced expression both of chemokines such as eotaxin and TARC as well as of adhesion molecules such as ICAM-1 and VCAM-1, all of which together promote the activation and infiltration of eosinophils and Th2 lymphocytes. In contrast, corneal epithelial cells suppress such reactions by physically separating corneal fibroblasts from bioactive substances in tear fluid. Exaggerated proliferation of and deposition of extracellular matrix by conjunctival fibroblasts likely exacerbate conjunctival inflammation. Restoration of an intact corneal epithelium and inhibition of the activities of corneal and conjunctival fibroblasts may provide a basis for the development of new treatments for severe ocular allergic diseases such as VKC.

The control of allergic conjunctivitis by suppressor of cytokine signaling (SOCS)3 and SOCS5 in a murine model

Allergic conjunctivitis (AC) is a common allergic eye disease characterized by clinical symptoms such as itchiness, conjunctival congestion, elevated Ag-specific IgE, mast cell activation, and local eosinophil infiltration. In this study we established a murine model for Ag-induced AC to understand the pathogenesis of the disease. Cell transfer experiments indicated that AC can be divided into early and late phase responses (EPR and LPR). EPR was associated with IgE responses, leading to itchiness, whereas LPR was characterized by local eosinophil infiltration. Both EPR and LPR were significantly inhibited in STAT6-deficient mice, and adoptive transfer of Th2 cells reconstituted LPR. Furthermore, SOCS3 was highly expressed at the disease site, and T cell-specific expression of SOCS3 deteriorated clinical and pathological features of AC, indicating that Th2-mediated SOCS3 expression controls the development and persistence of AC. Reduction of the expression level in SOCS3 heterozygous mice or inhibition of function in dominant-negative SOCS3 transgenic mice clearly reduced the severity of AC. In contrast, constitutive expression of SOCS5, a specific inhibitor of IL-4 signaling, resulted in reduced eosinophil infiltration. These results suggest that negative regulation of the Th2-mediated response by dominant-negative SOCS3 and SOCS5 could be a target for therapeutic intervention in allergic disease.

The therapeutic potential in targeting CCR5 and CXCR4 receptors in infectious and allergic pulmonary disease

Targeting chemokines and chemokine receptors in various acute and chronic pulmonary diseases remains a vibrant area of basic and clinical research despite major hurdles including cross-species barriers, toxicity, and redundancy. In this review, we draw upon our basic research with a murine model in which innate and acquired immunity are linked in the development and maintenance of chronic asthma due to Aspergillus fumigatus. Using intact and genetically altered mice, studies have also been undertaken to elucidate safe and effective therapeutic strategies that interrupt the initiation and amplification of inflammatory and immune events that follow the intrapulmonary introduction of Aspergillus into A. fumigatus-sensitized mice. These events include resident immune cell activation, immune and inflammatory cell recruitment to the airways, changes in lung physiology, and profound changes in the architecture of the airway due to the activation of lung resident cells. The expression of 2 major chemokine receptors, namely, CC chemokine receptor (CCR) 5 and CXC chemokine receptor (CXCR) 4, has been identified and their roles in innate and acquired immune events during fungal asthma have been explored. CCR5 and CXCR4 are best known for their roles in human immunodeficiency virus-1 (HIV-1) infection, but both are attractive targets in the context of overt inflammatory and remodeling responses in the lung. This avenue of research is markedly enhanced by the existence of numerous small molecule antagonists that are available to selectively target these receptors.

Macrophage inflammatory protein-1

Macrophage inflammatory protein (MIP)-1alpha was identified 15 years ago as the first of now four members of the MIP-1 CC chemokine subfamily. These proteins termed CCL3 (MIP-1alpha), CCL4 (MIP-1beta), CCL9/10 (MIP-1delta), and CCL15 (MIP-1gamma) according to the revised nomenclature for chemokines are produced by many cells, particularly macrophages, dendritic cells, and lymphocytes. MIP-1 proteins, which act via G-protein-coupled cell surface receptors (CCR1, 3, 5), e.g. expressed by lymphocytes and monocytes/macrophages (MPhi), are best known for their chemotactic and proinflammatory effects but can also promote homoeostasis. The encouraging results of preclinical studies in murine models of inflammation, i.e. asthma, arthritis, or multiple sclerosis, have led to the development of potent CCR3 and 5 antagonists, some of which are currently being tested in first clinical trials.

Chemokines in acute respiratory distress syndrome

A characteristic feature of all inflammatory disorders is the excessive recruitment of leukocytes to the site of inflammation. The loss of control in trafficking these cells contributes to inflammatory diseases. Leukocyte recruitment is a well-orchestrated process that includes several protein families including the large cytokine subfamily of chemotactic cytokines, the chemokines. Chemokines and their receptors are involved in the pathogenesis of several diseases. Acute lung injury that clinically manifests as acute respiratory distress syndrome (ARDS) is caused by an uncontrolled systemic inflammatory response resulting from clinical events including major surgery, trauma, multiple transfusions, severe burns, pancreatitis, and sepsis. Systemic inflammatory response syndrome involves activation of alveolar macrophages and sequestered neutrophils in the lung. The clinical hallmarks of ARDS are severe hypoxemia, diffuse bilateral pulmonary infiltrates, and normal intracardiac filling pressures. The magnitude and duration of the inflammatory process may ultimately determine the outcome in patients with ARDS. Recent evidence shows that activated leukocytes and chemokines play a key role in the pathogenesis of ARDS. The expanding number of antagonists of chemokine receptors for inflammatory disorders may hold promise for new medicines to combat ARDS.

Potential role of c-Jun NH2-terminal kinase in allergic airway inflammation and remodelling: effects of SP600125

Asthma is a chronic inflammatory disease of the airways associated with structural changes such as increased airway smooth muscle mass, which may contribute to impairment of lung function. To determine whether c-Jun NH2-terminal kinase (JNK) of the mitogen-activated protein kinase signalling pathway participated in these changes, the effects of an inhibitor, SP600125 (anthra [1, 9-cd] pyrazole-6 (2H)-one), were examined in a murine model of chronic airway inflammation and remodelling. Mice sensitised to ovalbumin were exposed to ovalbumin aerosol and were treated with SP600125 [30 mg kg(-1) intraperitoneal (i.p.)] on days of exposure. SP600125 significantly reduced eosinophil and lymphocyte numbers in bronchoalveolar lavage fluid, suppressed eosinophilic inflammation within the bronchial submucosa, inhibited goblet cell hyperplasia, and increased airway smooth muscle cell number in allergen-exposed mice. SP600125 also inhibited allergen-induced increase in bronchial responsiveness. SP600125 inhibited JNK activity in the challenged lungs. Although SP 600125 may also have other effects, we conclude that c-Jun NH2-terminal kinase may play a role in allergen-induced inflammation and remodelling associated with bronchial hyperresponsiveness.

The role of RANTES in a murine model of food allergy

Food allergy is an important and common health issue, and there is a need to identify and characterize the sensitizing mechanisms. One of the common causes of food allergy is ovalbumin (OVA), a dietary antigen from eggs. We hypothesized that OVA-induced food allergy in the gut involves the activation of the chemokine regulated on activation, normal T cell expressed and secreted (RANTES), which then recruits eosinophils to lesioned tissue. The purpose of this study was to clarify whether RANTES expression correlates with eosinophil infiltration in the gut of OVA-sensitized BALB/c mice in response to oral OVA challenge. BALB/c mice were immunized with OVA 1 microg and sensitized after 2 weeks by intragastric administration of OVA. Sensitization to the oral OVA challenge was analyzed by examining eosinophil infiltration into the gut tissue (immunohistochemistry), mucosal eosinophil cationic protein (ECP) concentration, and RANTES mRNA expression (reverse-transcriptase polymerase chain reaction and Southern blotting) at 3, 6, 12, and 24 h after the challenge. There was marked edema of the intestinal villi, and eosinophil infiltration to the lamina propria peaked at 6 h in OVA-sensitized mice. RANTES mRNA expression peaked at 3 h and 6 h and declined thereafter. The expression of RANTES mRNA in the allergic mice was much higher than in the nonallergic, normal, or unsensitized control mice. Tissue eosinophilia and intestinal ECP levels were significantly correlated with the RANTES mRNA level. We conclude that RANTES may play a central role in the pathogenesis of food-mediated gastrointestinal allergy.

Cytokine-regulated accumulation of eosinophils in inflammatory disease

The role of cytokines in the accumulation of eosinophil granulocytes in inflamed tissue has been studied extensively during recent years, and these molecules have been found to participate throughout the whole process of eosinophil recruitment. Haematopoietic cytokines such as IL-3, IL-5 and GM-CSF stimulate the proliferation and differentiation of eosinophils in the bone marrow, and the release of mature eosinophils from the bone marrow into the blood is probably promoted by IL-5. Priming of eosinophils in the blood following, for example, allergen challenge is performed mainly by IL-3, IL-5 and GM-CSF. An important step in the extravasation of eosinophils is their adhesion to the vascular endothelium. Adhesion molecules are upregulated by, e.g. IL-1, IL-4, TNF-alpha and IFN-gamma and the same cytokines may also increase the affinity of adhesion molecules both on eosinophils and endothelial cells. Finally, a number of cytokines have been shown to act as eosinophil chemotactic factors, attracting the cells to the inflammatory focus in the tissue. Some of the most important eosinophil chemoattractant cytokines are IL-5, IL-8, RANTES, eotaxin, eotaxin-2, eotaxin-3, MCP-3, MCP-4 and TNF-alpha. Th2 cells, mast cells and epithelial cells are important sources of proinflammatory cytokines, but in recent years, the eosinophils have also been recognized as cytokine-producing and thereby immunoregulatory cells. The aim of this paper is to review the role of cytokines in the process of eosinophil recruitment in asthma, allergy and ulcerative colitis.

The role of eosinophilic leukocytes in pathogenesis of bronchial asthma

Pathogenesis of bronchial asthma has not been completely understood. Eosinophilic leukocytes accumulate in high numbers in the lungs, blood and sputum of asthmatic patients. Peripheral blood eosinophilia has been identified as a risk factor for the development of airway obstruction. Prominent eosinophilic inflammatory infiltrate in the bronchial mucosa and correlation between eosinophil numbers and disease severity supports the hypothesis that eosinophils are central inflammatory cells capable of inducing pathophysiological features of asthma. Activated eosinophils secrete a wide range of preformed and newly generated mediators that damage the bronchial epithelium, contract smooth muscle, increase mucous secretion and cause vasodilatation. There is ample evidence that oxidants generation is increased during an asthma exacerbation. Many investigations indicate that airway and blood eosinophils produce more oxidants in asthmatic patients compared with control subjects.

Mechanisms of basal and cytokine-induced uptake of glucose in normal human eosinophils: relation to apoptosis

A link between glucose transport and apoptosis was suggested. We studied the mechanisms of glucose transport in human eosinophils by means of the uptake of the positron emitting analogue, 18Fluoro-2-Deoxyglucose (FDG) and apoptosis by means of flow cytometry. FDG uptake was inhibited by antibodies to GLUT1, 3 and 4 and by cytochalasin B. The anti-apoptotic principles IL-5, GM-CSF, IL-3 enhanced the uptake, whereas the apoptosis-inducing principles anti-CD95 (anti-Fas) and exposure to serum-coated Sephadex particles caused a reduction. Also TNF-alpha enhanced the uptake. Other cytokines such as IL-2, IL-4, IL-8, RANTES and MCP-3 had no effect on the glucose uptake. 2-Deoxyglucose, antibodies to GLUT4 and CD95 induced apoptosis. The basal FDG-uptake was unaffected by PKC inhibitors Ro-31-8220, Gö-6983 and Gö-6976, whereas the latter inhibited the IL-5-enhanced uptake possibly due to the inhibition of PKC(mu). Protein tyrosine kinase and PI-3 kinase inhibitors inhibited IL-5-enhanced FDG-uptake only. In contrast MEK inhibitors inhibited the basal uptake only. Inhibitors of p38 MAPkinase inhibited both basal and IL-5 enhanced uptake. We conclude that glucose uptake in eosinophils is governed by specific intracellular mechanisms involving mobilization of GLUTs, Ca2+ and the activation of the MAP kinase pathway and that the IL-5-enhanced uptake uniquely seems to involve PKC(mu) activity. Our results suggest a close link between apoptosis and glucose transport in human eosinophils.

2. Cytokines and chemokines

Cytokines and chemokines are redundant secreted proteins with growth, differentiation, and activation functions that regulate and determine the nature of immune responses and control immune cell trafficking and the cellular arrangement of immune organs. Which cytokines are produced in response to an immune insult determines initially whether an immune response develops and subsequently whether that response is cytotoxic, humoral, cell-mediated, or allergic. A cascade of responses can be seen in response to cytokines, and often several cytokines are required to synergize to express optimal function. An additional confounding variable in dissecting cytokine function is that each cytokine may have a completely different function, depending on the cellular source, target, and, most important, specific phase of the immune response during which it is presented. Numerous cytokines have both proinflammatory and anti-inflammatory potential; which activity is observed depends on the immune cells present and their state of responsiveness to the cytokine. For this chapter, cytokines are grouped according to those that are mononuclear phagocytic-derived or T-lymphocytic-derived; that mediate cytotoxic (antiviral and anticancer), humoral, cell-mediated, or allergic immunity; and that are immunosuppressive. The biology of chemokines are then reviewed, grouped by family.

Meconium aspiration produces airway hyperresponsiveness and eosinophilic inflammation in a murine model

Meconium aspiration syndrome is a cause of significant morbidity and mortality in the perinatal period and has been implicated in the pathogenesis of airway dysfunction. In this study, we developed a murine model to evaluate the effects of meconium aspiration on airway physiology and lung cellular responses. Under light anesthesia, BALB/c mice received a single intratracheal instillation of meconium or physiological saline. Respiratory mechanics were measured in unrestrained animals and expressed as percent increase in enhanced pause to increasing concentrations of methacholine (MCh). Furthermore, we assessed the changes in cells and cytokines into the bronchoalveolar lavage fluid (BALF). We found meconium aspiration produced increased airway responsiveness to MCh at 7 days. These functional changes were associated with lymphocytic/eosinophilic inflammation, goblet cell metaplasia, and increased concentrations of IL-5 and IL-13 in the BALF. Our findings suggest meconium aspiration leads to alterations of airway function, lung eosinophilia, goblet cell metaplasia, and cytokine imbalance, thus providing the first evidence of meconium-induced airway dysfunction in a mouse model.