Interleukin 4 is localized to and released by human mast cells

Th2 cells and cytokine networks in allergic inflammation of the lung

The cytokines released from Th2 and Th2-like cells are likely to be central to the pathophysiolgy of asthma and allergy, contributing to aberrant IgE production, eosinophilia and, perhaps, mucosal susceptibility to viral infection. IL-4 has emerged as a central target, not only for B cell IgE production, but also in the commitment of both CD4+ and CD8+ T cells to cells with Th2 effector function capable of secreting IL-5 resultlng in eosinophilic inflammation. In view of the central role of this cytokine and the evidence that glucocorticoids are unable to modify many IL-4 dependent effects, Th2 inhibitors may prove to be novel therapies for the treatment of bronchial asthma.

Interleukin-4 (IL-4) enhances and soluble interleukin-4 receptor (sIL-4R) inhibits histamine release from peripheral blood basophils and mast cells in vitro and in vivo

The aim of the study was to analyse the effect of interleukin-4 (IL-4) on allergen and anti-IgE mediated histamine release from basophils and human skin mast cells and to assess whether soluble recombinant interleukin-4 receptor (sIL4R) can inhibit these effects. Anti-IgE stimulated histamine release from peripheral blood basophils and mast cells of atopic donors was enhanced after preincubation with IL-4, whereas after preincubation with sIL-4R it was inhibited. These effects were even more pronounced when samples were stimulated with a clinically relevant allergen. In IL-4 preincubated skin mast cells, there was a similar enhancement of anti-IgE stimulated histamine release, which could again be inhibited by sIL-4R. The effects of IL-4 and sIL4R were dose- and time-dependent. Mice sensitized to ovalbumin and treated with soluble recombinant murine sIL-4R showed significantly reduced immediate-type cutaneous hypersensitivity responses compared with untreated mice. These in vivo effects were IgE independent, since there were no significant differences in total and allergen specific IgE/IgG1 antibody titres between treated and untreated mice. This indicates that IL4 exerts priming effects on histamine release by effector cells of the allergic response and that these effects are potently antagonized by soluble IL-4R both in vitro and in vivo.

Cytokine pathways in allergic disease

Cytokines are critical in allergic intercellular communication networks, and they contribute to disease pathology through the recruitment and activation of pro-inflammatory leukocytes and in chronic disease to pro-fibrotic/remodeling events. Th2 cytokines predominate primarily in mild to moderate allergic asthma, although clinical trials with inhibitors of IL-4 and IL-5 have not provided the robust efficacy observed in animal models of allergy. These results not only highlight the complexity of allergic disease, but they also point to the importance of other cytokine networks in driving pathology. The heterogeneous nature of the disease is emphasized by the fact that the Th2/Th1/Th17 cytokine balance can be influenced by the initiating allergic trigger. For example, the house dust mite allergen Der p 2 mimics the activity of MD-2 by presenting lipopolysaccharide to Toll-like receptor-4 for the activation of inflammatory genes including innate-type cytokines. Here we discuss the functions of the novel cytokine players, thymic stromal lymphopoetin (TSLP), IL-33, IL-25, and IL-9 and delineate nonredundant roles for IL-4 and IL-13 in allergic disease. Persistent efforts in the characterization of these and other cytokine networks will be essential for understanding the complex pathogenic mechanisms that underpin allergic disease and for guiding targeted therapeutic interventions.

Kit (W-sh) mice develop earlier and more severe experimental autoimmune encephalomyelitis due to absence of immune suppression

Mast cells (MCs) have been thought to play a pathogenic role in the development of autoimmune diseases, including experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. However, an immunoregulatory function of these cells has recently been suggested. We investigated the role of MCs in EAE using the W(-sh) mouse strain, which is MC deficient. W(-sh) mice developed earlier and more severe clinical and pathological disease with extensive demyelination and inflammation in the CNS. The inflammatory cells were mainly composed of CD4(+) T cells, monocyte/macrophages, neutrophils, and dendritic cells. Compared with wild-type mice, MC-deficient mice exhibited an increased level of MCP-1/CCR2 and CD44 expression on CD4(+) T cells in addition to decreased production of regulatory T cells, IL-4, IL-5, IL-27, and IL-10. We also found that levels of IL-17, IFN-γ, and GM-CSF were significantly increased in peripheral lymphocytes from immunized W(-sh) mice compared with those in peripheral lymphocytes from wild-type mice. Reconstitution of W(-sh) mice downregulated susceptibility to EAE, which correlated with MC recruitment and regulatory T cell activation in the CNS. These findings indicate that responsiveness is not required in the pathogenesis of inflammatory demyelination in the CNS and that, in the absence of MCs, increased MCP-1, CCR2, IL-17, IFN-γ, CD44, and other inflammatory molecules may be responsible for increased severity of EAE.

Non-FcεR bearing mast cells secrete sufficient interleukin-4 to control Francisella tularensis replication within macrophages

Mast cells have classically been implicated in the triggering of allergic and anaphylactic reactions. However, recent findings have elucidated the ability of these cells to selectively release a variety of cytokines leading to bacterial clearance through neutrophil and dendritic cell mobilization, and suggest an important role in innate host defenses. Our laboratory has established a primary bone marrow derived mast cell-macrophage co-culture system and found that mast cells mediated a significant inhibition of Francisella tularensis live vaccine strain (LVS) uptake and replication within macrophages through contact and the secreted product interleukin-4 (IL-4). In this study, we utilized P815 mast cells and J774 macrophages to further investigate whether mast cell activation by non-FcεR driven signals could produce IL-4 and control intramacrophage LVS replication. P815 supernatants collected upon activation by the mast cell activating peptide MP7, as well as P815 cells co-cultured with J774 macrophages, exhibited marked inhibition of bacterial uptake and replication, which correlated with the production of IL-4. The inhibition noted in vitro was titratable and preserved at ratios relevant to cellular infiltration events following pulmonary challenge. Collectively, our data suggest that both primary mast cell and P815 mast cell (lacking FcεR) secreted IL-4 can control intramacrophage Francisella replication.

Interstitial cells of Cajal, macrophages and mast cells in the gut musculature: morphology, distribution, spatial and possible functional interactions

Interstitial cells of Cajal (ICC) are recognized as pacemaker cells for gastrointestinal movement and are suggested to be mediators of neuromuscular transmission. Intestinal motility disturbances are often associated with a reduced number of ICC and/or ultrastructural damage, sometimes associated with immune cells. Macrophages and mast cells in the intestinal muscularis externa of rodents can be found in close spatial contact with ICC. Macrophages are a constant and regularly distributed cell population in the serosa and at the level of Auerbach's plexus (AP). In human colon, ICC are in close contact with macrophages at the level of AP, suggesting functional interaction. It has therefore been proposed that ICC and macrophages interact. Macrophages and mast cells are considered to play important roles in the innate immune defence by producing pro-inflammatory mediators during classical activation, which may in itself result in damage to the tissue. They also take part in alternative activation which is associated with anti-inflammatory mediators, tissue remodelling and homeostasis, cancer, helminth infections and immunophenotype switch. ICC become damaged under various circumstances - surgical resection, possibly post-operative ileus in rodents - where innate activation takes place, and in helminth infections - where alternative activation takes place. During alternative activation the muscularis macrophage can switch phenotype resulting in up-regulation of F4/80 and the mannose receptor. In more chronic conditions such as Crohn's disease and achalasia, ICC and mast cells develop close spatial contacts and piecemeal degranulation is possibly triggered.

Modulation of cytokines and transcription factors (T-Bet and GATA3) in CD4 enriched cervical cells of Chlamydia trachomatis infected fertile and infertile women upon stimulation with chlamydial inclusion membrane proteins B and C

BACKGROUND

Chlamydial Inclusion membrane proteins (Incs), are involved in biochemical interactions with host cells and infecting Chlamydiae. We have previously reported the role of two Chlamydia trachomatis (CT) Incs, namely IncB and IncC in generating host immunity in CT infected women. Emerging data shows involvement of Inc stimulated CD4 positive T cells in aiding host immunity in infected fertile and infertile women through the secretion of interferon gamma. However the lack of data on the intra-cytokine interplay to these Incs in infected cell milieu prompted us to investigate further.

METHODS

A total of 14 CT-positive fertile, 18 CT-positive infertile women and 25 uninfected controls were enrolled in this study. CD8 depleted, CD4 enriched cervical cells were isolated and upon stimulation with IncB and IncC, modulation of cytokines (Interleukin (IL)-1 Beta, IL-4, IL-5, IL-6, IL-10, Interferon-gamma, IL-12, IL-23, Tumor Necrosis Factor-alpha and Granulocyte macrophage colony-stimulating factor (GM-CSF) and T cell lineage regulating transcription factors T-Bet and GATA3 was determined by real-time reverse-transcriptase (RT)-PCR and ELISA.

RESULTS

Significant higher expression (P < 0.05) of Interferon-gamma, IL-12, IL-23 and GM-CSF were found in Inc-stimulated CD4 enriched cervical cells of CT-positive fertile women and contrastingly high IL-1 Beta, IL-4, IL-5, IL-6 and IL-10 levels were found in CT-positive infertile women. Positive correlation (P < 0.05) was found between Interferon-gamma and T-Bet levels in CT-positive fertile women and IL-4 mRNA and GATA3 levels in CT-positive infertile patients upon IncB and IncC stimulation.

CONCLUSION

Overall our data shows that CT IncB and IncC are able to upregulate expression of cytokines, namely interferon-gamma, IL-12, IL-23 and GM-CSF in CT-positive fertile women while expression of IL-1 Beta, IL-4, IL-5, IL-6 and IL-10 were upregulated in CT-positive infertile women. Our study also suggests that Incs are able to modulate expression of T cell lineage determinants indicating their involvement in regulation of immune cells.

Induction of IL-4 release and upregulated expression of protease activated receptors by GM-CSF in P815 cells

GM-CSF has been showed to be able to induce up-regulated receptor and cytokine expression in mast cells in inflammatory conditions. However, little is known of its effects on protease activated receptor (PAR) expression and Th2 cytokine secretion from mast cells. In the present study, we examined potential influence of GM-CSF on mast cell PAR expression and IL-4 and IL-10 release by using flow cytometry analysis, quantitative real time PCR, ELISA and cellular activation of signaling ELISA (CASE) techniques. The results showed that GM-CSF induced up to 3.0-fold increase in IL-4 release from P815 cells, and FSLLRY-NH(2) and trans-cinnamoyl (tc)-YPGKF-NH(2) did not affect GM-CSF induced IL-4 release. GM-CSF reduced tryptase and trypsin induced IL-4 release by up to approximately 55.8% and 70.3%, respectively. GM-CSF elicited the upregulated expression of PAR-1, PAR-2, PAR-3 and PAR-4 mRNAs, but enhanced only PAR-4 protein expression in P815 cells. U0126, PD98059 and LY204002 almost completely abolished GM-CSF induced IL-4 release when they were preincubated with P815 cells for 30 min, indicating ERK and Akt cell signaling pathways may be involved in the event. In conclusion, GM-CSF can stimulate IL-4 release from mast cells through an ERK and Akt cell signaling pathway dependent, but PAR independent mechanism. GM-CSF may serve as a regulator for IL-4 production in mast cells and through which participates in the mast cell related inflammation.

Interaction between prostaglandin D and chemoattractant receptor-homologous molecule expressed on Th2 cells mediates cytokine production by Th2 lymphocytes in response to activated mast cells

The mechanisms by which immunologically activated mast cells stimulate the production of proinflammatory cytokines by T helper type 2 (Th2) lymphocytes were investigated in a human cell culture system. Supernatants collected from cord blood-derived mast cells after treatment with immunoglobulin E (IgE)/anti-IgE contained an activity that stimulated the production of interleukin (IL)-4, IL-5 and IL-13 (both mRNA and protein) by Th2 lymphocytes. This activity was not detected in supernatants from unactivated mast cells and its production was inhibited by treatment of activated mast cells with the cyclo-oxygenase inhibitor diclofenac. The concentration of diclofenac used inhibited completely the production of prostaglandin D(2) (PGD(2)) but did not inhibit the release of histamine or leukotriene C(4). The effect of supernatants from activated mast cells was mimicked by exogenous PGD(2) at concentrations similar to those detected in the cultures of activated mast cells, and addition of exogenous PGD(2) to supernatants from diclofenac-treated mast cells restored their ability to stimulate Th2 cytokine production. The ability of the mast cell supernatants to stimulate production of Th2 cytokines was not affected by addition of diclofenac to the Th2 cells directly, indicating that the production, but not the action, of the factor was sensitive to diclofenac treatment. Inhibition of chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2) abolished the effect of the mast cell supernatants on Th2 cytokine production. These data indicate that mast cells have the ability to stimulate Th2 cells to elaborate cytokines independently of T cell receptor activation or co-stimulation and this response is mediated by PGD(2) acting upon CRTH2 expressed by Th2 cells.

The predictive value of IgE as biomarker in asthma

BACKGROUND

The evidence for a causal relationship between allergens and asthma depends on epidemiologic findings showing a strong association between specific immunoglobulin E (IgE) antibodies or total IgE and asthma.

OBJECTIVE

To clarify the relationship between total serum IgE levels and asthma.

STUDY DESIGN

A cross-sectional study.

PATIENTS AND METHODS

A total of 562 asthmatic patients were included in the study, and their age range was from 17 to 52 years. The subjects included in the study were outpatients from the Asthma and Allergy Centre or Samara General Hospital outpatients Clinic. The diagnosis of asthma was performed by a specialist physician and was established according to the National Heart Blood and Lung Institute/World Health Organization (NHLBI/WHO) workshop on the Global Strategy for Asthma.

RESULTS

This study indicated that mean serum IgE level was 554 +/- 447 IU/mL in asthmatic patients, while that of the control population was 69 +/- 33 IU/mL. There was no overlap in the values of 95% confidence interval (CI) of higher control limit and lower asthmatic limit values. Addition of two standard deviations to the mean IgE value of the control group (134 IU/mL) does not overlap with the lower 95% CI of the asthmatic group. However, serum IgE was within normal values in 5.9% of asthmatic patients in our study population. There was an inverse correlation between serum IgE levels and forced expiratory volume in 1 second (FEV(1)) predicted percent for patients with asthma (r = -0.73, p < 0.0001). The predictive value of serum IgE in asthma was determined using Receiver Operating Characteristics (ROC) curve method. From the ROC curve, it can be seen that it is possible to get both high sensitivity and high specificity if the right cut-off value was chosen. In fact, a cut-off of 200 IU/mL would indicate sensitivity of 93% and specificity of 91% in this group of patients and control subjects. Following immunotherapy there was 36% reduction in total serum IgE level. The value of IgE was significantly reduced (p < 0.001) from 956 +/- 378 IU/mL at baseline to 613 +/- 194 IU/mL after treatment.

CONCLUSION

Serum IgE level was predictive in asthma, and it may be used to differentiate between asthmatic and non-asthmatic individuals in conjunction with other biomarkers. Specific immunotherapy reduced serum total IgE level in 36% of patients with asthma.

SWAP-70 regulates mast cell FcepsilonRI-mediated signaling and anaphylaxis

Mast cells, perhaps best known by their ability to trigger allergic reactions after stimulation through the FcepsilonRI, express the unusual phosphatidylinositol 3-kinase (PI3K)-dependent, Rac-binding protein SWAP-70. Here, we show that the IgE-mediated passive cutaneous and the systemic anaphylactic responses are strongly reduced in SWAP-70(-/-) mice. Cultured SWAP-70(-/-) immature bone marrow mast cells (BMMC) are also impaired in FcepsilonRI-mediated degranulation, which can be restored by expression of exogenous wild-type SWAP-70, but less so if a phosphatidylinositol trisphosphate (PIP(3)) binding mutant is expressed. SWAP-70 itself supports inositol-3-phosphate and PIP(3) production, the latter indicating a potential feedback from SWAP-70 towards PI3K. FcepsilonRI-stimulated transcription and release of cytokines is controlled by SWAP-70. Key FcepsilonRI signal transduction events like activation of LAT by phosphorylation, activation of Akt/PKB and of p38 MAP kinase are reduced in SWAP-70(-/-) BMMC, but ERK is strongly hyperactivated. Some requirements for SWAP-70 were apparent only under limited-strength signaling conditions. We suggest that SWAP-70 defines a new element of efficient mast cell activation upon FcepsilonRI signaling, important for the control of mast cell-dependent anaphylaxis.

Modulation of mast cell proteinase-activated receptor expression and IL-4 release by IL-12

It has been recognized that protease-activated receptors (PARs), interleukin (IL)-4 and IL-6 are involved in the pathogenesis of allergic diseases, and that IL-12 plays a role in adaptive immune response. However, little is known of the effect of IL-12 on protease-induced cytokine release from mast cells. In the present study, we examined potential influence of IL-12 on mast cell PAR expression and IL-4 and IL-6 release. The results showed that IL-12 downregulated the expression of PAR-2 and upregulated expression of PAR-4 on P815 cells. It also downregulated expression of PAR-2 mRNA, and upregulated expression of PAR-1, PAR-3 and PAR-4 mRNAs. However, IL-12 enhanced trypsin- and tryptase-induced PAR-2 and PAR-2 mRNA expression. It was observed that IL-12 induced release of IL-4, but reduced trypsin- and tryptase-stimulated IL-4 secretion from P815 cells. PD98059, U0126 and LY294002 not only abolished IL-12-induced IL-4 release but also inhibited IL-12-induced phosphorylation of extracellular signal-regulated kinase and Akt. In conclusion, IL-12 may serve as a regulator in keeping the balance of Th1 and Th2 cytokine production in allergic inflammation.

Ocular anti-allergic compounds selectively inhibit human mast cell cytokines in vitro and conjunctival cell infiltration in vivo

BACKGROUND

Conjunctival mast cells (MCs) are important effector cells in seasonal allergic conjunctivitis, via histamine and cytokine secretion. Several new anti-allergic eye drops stabilize MCs and block histamine receptors, but their anti-inflammatory effects are unclear.

OBJECTIVE

Anti-allergic drugs were compared for their anti-inflammatory effects in an in vitro model of human MC activation and in an experimental murine model of allergic conjunctivitis.

METHODS

Human cord blood stem cell-derived (CBMC) and conjunctival biopsy-derived MCs were stimulated via FcepsilonRI, degranulation and histamine release were assayed at 1 h and cytokine secretion at 24 h using multiplex arrays. Mice sensitized to short ragweed pollen were given anti-allergics topically before allergen challenge, and conjunctival immuno-staining was performed at 24 h.

RESULTS

After a 1 h stimulation, 80% of the CBMC had degranulated and secreted histamine (27.9+/-4.7 ng/10(6) cells; P<0.05). Pre-treatment by all drugs significantly reduced histamine and TNF-alpha, whereas IL-5, IL-8, IL-10 and TNF-beta profiles were differentially decreased. For conjunctival biopsy-derived cultures (n=11), FcepsilonR1 stimulation increased histamine, TNF-alpha, TNF-beta, IL-5 and IL-8 levels and the production of IL-5, IL-6 (P<0.05), histamine and IL-8 (P<0.01) was inhibited by epinastine. In vivo, epinastine and olopatadine pre-treatment significantly reduced the clinical scores and eosinophil numbers (n=6; P<0.05) while epinastine also reduced neutrophils (P<0.02).

CONCLUSION

Differential effects on MC cytokine inhibition were observed, with epinastine inhibiting MC secretion of IL-5, IL-8, IL-10 and conjunctival neutrophil infiltration. The anti-allergic drugs have anti-histamine and mast-cell stabilizing properties but might differ in clinical improvement depending on the individual and the cytokines involved.

Mast cell mediators in allergic inflammation and mastocytosis

Mast cells possess an array of potent inflammatory mediators capable of inducing acute symptoms after cell activation, including urticaria, angioedema, bronchoconstriction, diarrhea, vomiting, hypotension, cardiovascular collapse, and death in few minutes. In contrast, mast cells can provide an array of beneficial mediators in the setting of acute infections, cardiovascular diseases, and cancer. The balance between the detrimental and beneficial roles of mast cells is not completely understood. Although the symptoms of acute mast cell mediator release can be reversed with epinephrine, adrenergic agonists, and mediator blockers, the continued release of histamine, proteases, prostaglandins, leukotrienes, cytokines, and chemokines leads to chronic and debilitating disease, such as mastocytosis. Identification of the molecular factors and mechanisms that control the synthesis and release of mast cell mediators should benefit all patients with mast cell activation syndromes and mastocytosis.

Enhancement of the release of inflammatory mediators by substance P in rat basophilic leukemia RBL-2H3 cells

Substance P (SP), a neurotransmitter, may play an important role in neurogenic inflammation. Ginseng has been used extensively in traditional medicine; however, few studies were focused on their anti-allergic effect. Therefore, the effect and mechanism of ginsenoside Rb1 on the SP enhancement of allergic mediators were explored. In this study, SP and dinitrophenyl-bovine serum albumin (DNP-BSA) were used to activate rat basophilic leukemia (RBL)-2H3 cells. The cultured supernatants were assayed for histamine, leukotriene C(4)(LTC(4)) and interleulin-4 (IL-4) production. The mitogen-activated protein kinases (MAPKs) signaling pathway was determined by Western blotting analysis. We found that IgE/DNP-BSA, SP, ginsenoside Rb1, or MAPK specific inhibitors had no effect on cell viability and cytotoxicity. SP (30 microM) alone, did not induce histamine and LTC(4) release, but it enhanced allergen-induced histamine and LTC(4) release. In addition, SP significantly induced and enhanced allergen-activated IL-4. Ginsenoside Rb1 dose-dependently inhibited these effects. SP enhanced the allergen-activated ERK pathway in RBL-2H3 cells, and Rb1 effectively inhibited the ERK pathway activation. Although MAPK specific inhibitors suppressed LTC(4) and IL-4, only U0126 inhibited the SP enhanced histamine release. These results demonstrate that Rb1 dose-dependently inhibited SP enhanced allergen-induced mediator release and its mechanism was through the inhibition of the ERK pathway.

Roles of IL-18 in basophils and mast cells

Basophils and mast cells are effecter cells in allergen/IgE-mediated immune responses. They induce type 1 immediate immune response in airway or other organ, resulting in bronchial asthma and other allergic diseases. However, they also play a critical role in host defense against infection with helminthes. Upon linkage of FcepsilonRI with a complex of allergen and IgE, basophils and mast cells release a large amount of Th2 cytokines and chemical mediators. Therefore these responses are "acquired allergic responses" and induce allergic diseases, such as bronchial asthma. However, basophils and mast cells derived from cultured bone marrow cells with IL-3 for 10 days express IL-18Ralpha chain and produce Th2 cytokines in response to the stimulation with IL-3 and IL-18 without FcepsilonRI cross-linkage. Furthermore, they produce Th2 cytokines upon stimulation with several TLR ligands, such as LPS. This finding may suggest the presence of allergen/IgE-independent allergic responses, which we would like to designate as "innate allergic response". However, in vivo treatment with IL-18 and IL-2 protects against gastrointestinal nematode infection by activating intestinal mucosal mast cells in STAT6-independent manner, suggesting the importance of innate allergic response against helminth infection. Here we discuss the functional role of IL-18-induced "innate allergic response" in disease and host defense.

Nuclear factor-kappa B-independent anti-inflammatory action of salicylate in human endothelial cells: induction of heme oxygenase-1 by the c-jun N-terminal kinase/activator protein-1 pathway

In contrast to aspirin, salicylate, its active metabolite, possesses profound anti-inflammatory properties without blocking cyclooxygenase. Inhibition of the transcription factor nuclear factor-kappaB (NF-kappaB) has been discussed to play a role in the anti-inflammatory profile of salicylate. However, NF-kappaB-independent effects of salicylate have been assumed but have up to now been poorly investigated. Therefore, the aim of the present study was to investigate NF-kappaB-independent anti-inflammatory mechanisms of salicylate in human umbilical vein endothelial cells using interleukin-4 (IL-4) as NF-kappaB-independent proinflammatory stimulus and P-selectin as inflammatory read-out parameter. Using quantitative real-time reverse transcription-polymerase chain reaction, we found that salicylate decreases IL-4-induced P-selectin expression. As judged by Western blot analysis, salicylate increased endothelial heme oxygenase-1 (HO-1) protein levels. Using both the HO-1 inhibitor tin(II) protoporphyrin IX and HO-1 antisense oligonucleotides, we causally linked the induction of HO-1 to the decrease of P-selectin. Moreover, we were interested in the signaling mechanisms leading to the up-regulation of HO-1 by salicylate. c-Jun NH2-terminal kinase (JNK) was found to be activated by salicylate, and we could causally link this activation to the induction of HO-1 by using the JNK inhibitor 1,9-pyrazoloanthrone. By applying activator protein-1 (AP-1) decoys, it was shown that the transcription factor AP-1 is crucially involved in the up-regulation of HO-1 downstream of JNK. In summary, our study introduces HO-1 as novel NF-kappaB-independent anti-inflammatory target of salicylate in human endothelial cells. Moreover, we elucidated the JNK/AP-1 pathway as crucial for the induction of HO-1 by salicylate.

Identification of an interleukin (IL)-25-dependent cell population that provides IL-4, IL-5, and IL-13 at the onset of helminth expulsion

Type 2 immunity, which involves coordinated regulation of innate and adaptive immune responses, can protect against helminth parasite infection, but may lead to allergy and asthma after inappropriate activation. We demonstrate that il25^−/− mice display inefficient Nippostrongylus brasiliensis expulsion and delayed cytokine production by T helper 2 cells. We further establish a key role for interleukin (IL)-25 in regulating a novel population of IL-4–, IL-5–, IL-13–producing non–B/non–T (NBNT), c-kit⁺, FcɛR1⁻ cells during helminth infection. A deficit in this population in il25^−/− mice correlates with inefficient N. brasiliensis expulsion. In contrast, administration of recombinant IL-25 in vivo induces the appearance of NBNT, c-kit⁺, FcɛR1⁻ cells and leads to rapid worm expulsion that is T and B cell independent, but type 2 cytokine dependent. We demonstrate that these IL-25–regulated cells appear rapidly in the draining lymph nodes, implicating them as a source of type 2 cytokines during initiation of worm expulsion.

The receptor for erythropoietin is present on cutaneous mast cells

Skin samples from patients with extra-mammary Paget disease, Bowen's disease, atopic dermatitis, psoriasis and non-lesional skin of nevus pigmentosus were immunohistochemically examined with an anti-soluble erythropoietin receptor antibody (anti-sEPOR antibody), and only the dermal mast cells positively stained in all skin samples were examined. These positively stained dermal cells were proved to be mast cells by double staining with anti-sEPOR antibody and either with anti-bikunin antibody or anti-tryptase antibody. Immunoelectron microscopically these EPOR were found in the secretory granules of the dermal mast cells. Further, EPOR in the mast cells may be consisting of only the extracellular domain of erythropoietin receptor molecule as the mast cells were immunohistochemically not reacted with an antibody to the C-terminal peptide of EPOR. Human mast cell line, HMC-1 cells has immunohistochemically the erythropoietin receptor, which was consisting of a 43 kDa major protein and a 20 kDa minor protein in the immunoelectrophoresis. These data may indicate that EPOR in the mast cells may not be the whole molecule, but probably the soluble one of EPOR.

Regulatory effect of atopic allergic reaction by Carpopeltis affinis

Carpopeltis affinis Okamura (CA, Halymeniaceae) has long been used as therapeutics for various allergic diseases in Korea. The precise effects of CA in experimental models, however, have remained unknown. We studied the effects of a methanol extract of CA on atopic allergic reaction. Histamine content was measured by the o-phthalaldehyde spectrofluorometric procedure. Cytokines were measured by a modified enzyme-linked immunosorbent assay. Cytotoxicity was determined by the 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. CA significantly inhibited the histamine release and beta-hexosaminidase release from rat peritoneal mast cells. CA also inhibited interleukin-8 and tumor necrosis factor-alpha secretion from the phorbol 12-myristate 13-acetate and A23187-induced HMC-1 cells (human mast cell line). 48 h exposure to CA (1.0, 10, and 100 microg/ml) had little effect on HMC-1 cell viability. Our results suggest that CA has an inhibitory effect on mast cell-dependent allergic reaction and thus may be useful in the treatment of atopic dermatitis.

Allergens in the pathogenesis of asthma: potential role of anti-immunoglobulin E therapy

Evidence suggests that allergy is a significant triggering factor in asthma in children and adults alike. In immunoglobulin (Ig) E-mediated allergic reactions, sensitization occurs when allergen-specific B cells are stimulated and switched to IgE antibody production by interleukin (IL)-4 and IL-13 provided by helper T cells type 2 (Th2). The IgE antibodies act by arming cells bearing either the high-affinity (FcepsilonRI) or low-affinity (FcepsilonRII or CD23) receptor. The subsequent interaction of allergen with IgE-FcepsilonRI complexes on mast cells and basophils causes cross-linking of receptors that triggers the release of a variety of inflammatory mediators, cytokines and chemokines. Therefore, the ability to lower circulating free IgE levels is desirable because most individuals are exposed to multiple allergens to which they are sensitive at any given time. Omalizumab (formerly known as rhuMAb-E25) is a recently developed humanized monoclonal anti-IgE antibody directed at the FcepsilonRI binding domain of human IgE. It inhibits binding of IgE to mast cells without provoking mast cell activation. Preliminary clinical data from randomized controlled trials have shown that the addition of omalizumab to standard asthma therapy reduces asthma exacerbations and decreases inhaled corticosteroid and rescue medication use. The compound is also well tolerated. Omalizumab represents a novel therapeutic approach in the management of asthma.

Molecular mechanisms of glucocorticoids in the control of inflammation and lymphocyte apoptosis

The immune system must be tightly controlled not only to guarantee efficient protection from invading pathogens and oncogenic cells but also to avoid exaggerated immune responses and autoimmunity. This is achieved through interactions amongst leukocytes themselves, by signals from stromal cells and also by various hormones, including glucocorticoids. The glucocorticoids are a class of steroid hormones that exert a wide range of anti-inflammatory and immunosuppressive activities after binding to the glucocorticoid receptor. The power of these hormones was acknowledged many decades ago, and today synthetic derivatives are widely used in the treatment of inflammatory disorders, autoimmunity and cancer. In this review, we summarize our present knowledge of the molecular mechanisms of glucocorticoid action, their influence on specific leukocytes and the induction of thymocyte apoptosis, with an emphasis on how molecular genetics has contributed to our growing, although still incomplete, understanding of these processes.

Bcl6 regulates Th2 type cytokine productions by mast cells activated by FcepsilonRI/IgE cross-linking

Bcl6-deficient (Bcl6-/-) mice displayed Th2 type inflammation, which caused by abnormality of non-lymphoid cells. However, initiators for the Th2 type inflammation were not clear. In order to elucidate the initiators, we investigated property and function of mast cells derived from Bcl6-/- mice. Mast cells were developed from bone marrow cells cultured with IL-3 (BMMCs). Although the development of BMMCs from Bcl6-/- mice was similar to that from wild-type mice, proliferation of Bcl6-/- BMMCs stimulated with IL-3 was slightly lower than that of wild-type BMMCs. When these BMMCs were stimulated by FcepsilonRI/IgE cross-linking, Bcl6-/- BMMCs produced Th2 cytokines more than wild-type BMMCs did. Thus, Bcl6-/- mast cells are one of the initiators for Th2 type inflammation in Bcl6-/- mice, and Bcl6 may be a molecular target for Th2 type allergic diseases.

c-Jun N-terminal kinase is involved in mercuric ions-mediated interleukin-4 secretion in mast cells

BACKGROUND

Interleukin (IL)-4 plays a prominent role in immune response. Mercuric compounds upregulate IL-4 expression in animal tissues, and this upregulation plays a role in mercuric-mediated immunomodulation. Mercuric ions-mediated IL-4 expression was observed in vitro in T lymphocytes and mast cells. In the present study, we investigated molecular mechanisms responsible for this effect of mercuric ions in mast cells.

METHODS

C1.MC/C57.1 mouse mast cells were exposed in vitro to increasing concentrations of Hg(2+) in the absence or presence of the specific c-Jun N-terminal kinase (JNK) inhibitor SP600125. The level of phosphorylated c-Jun in mast cells was determined by Western blotting, JNK activity assessed with in vitro kinase assay and the amount of secreted IL-4 determined by ELISA.

RESULTS

We observed that Hg(2+) upregulated c-Jun phosphorylation on Ser 73 at concentrations which overlapped concentrations mediating IL-4 secretion. Phosphorylation of c-Jun in mast cells was associated with an increase in JNK activity. The specific JNK inhibitor SP600125 abolished both mercuric-induced c-Jun phosphorylation and IL-4 secretion in mast cells.

CONCLUSIONS

These observations are consistent with the hypothesis that JNK is one of the signaling proteins mediating the effect of Hg(2+) on IL-4 expression in mast cells and is engaged in environmentally mediated immunomodulation.

Sargassum hemiphyllum inhibits atopic allergic reaction via the regulation of inflammatory mediators

Sargassum hemiphyllum (SH) has long been used in Korean folk medicine for the therapeutic treatment of various allergic diseases. The effects of SH in previous experimental models, however, have been inconclusive. We studied the effects of methanol extract of SH on mast cells. Our experiments showed that SH significantly inhibited compound 48/80-induced histamine and beta-hexosaminidase release from rat peritoneal mast cells. SH inhibited interleukin (IL)-8 and tumor necrosis factor (TNF)-alpha release induced by phorbol 12-myristate 13-acetate and A23187 from HMC-1, and it also showed an inhibitory effect on the anti-dinitrophenyl IgE antibody-induced passive cutaneous anaphylaxis reaction. In addition, SH inhibited the increase of TNF-alpha-induced NF-kappaB protein levels, transcription factor of TNF-alpha from 293T cells. A period of 48 h exposure to SH had little effect on HMC-1 cell viability. Our results suggest that SH has an inhibitory effect on the atopic allergic reaction and thus this may be useful in the treatment of allergic inflammatory diseases, such as atopic dermatitis.

Differential expression of CCR3 and CXCR3 by human lung and bone marrow-derived mast cells: implications for tissue mast cell migration

The selective microlocalization of mast cells within specific airway structures, such as the airway smooth muscle and submucosal glands, in asthma is important in the pathophysiology of inflammatory lung disease. Chemokines are likely candidates mediating mast cell migration into these tissue compartments. In this study, we have defined the chemokine receptor profile of human lung mast cells (HLMC) compared with mast cells derived from human bone marrow (BM) and the human mast cell line HMC-1. CXC chemokine receptor 3 (CXCR3) was the most highly expressed chemokine receptor on ex vivo HLMC analyzed by flow cytometry, and CXCR3 expression by mast cells in the bronchial mucosa was confirmed by immuno-histochemistry. CXCR3 was functional, inducing a rise in cytosolic-free Ca2+, actin reorganization, and chemotaxis in response to the CXC ligands CXCL9, -10, and -11. CXCR3 activation did not induce degranulation or cytokine synthesis. In addition, more than 10% of ex vivo HLMC expressed CC chemokine receptor 3, CXCR1, and CXCR4. It is interesting that CXCR3 was not expressed by human BM-derived mast cells, suggesting its expression is induced during tissue maturation. As CXCR3 ligands are elevated in many pulmonary diseases, CXCR3 may be important for determining the anatomical microlocalization of mast cells within the human lung.

Th2 induction by Nippostrongylus secreted antigens in mice deficient in B cells, eosinophils or MHC Class I-related receptors

The populations of immune system cells necessary for induction of the Th2 response have yet to be fully defined. Among the most consistent natural stimuli for Th2 responses are helminth parasites, such as the gastrointestinal nematode Nippostrongylus brasiliensis. Strong Th2 bias in immune responsiveness to live parasite infection can be reproduced by injection of a soluble Nippostrongylus excretory/secretory product (NES) collected from adult worm parasites in vitro. Injection of soluble NES induces a residual type-2 response (IL-13) even in IL-4-deficient mice, and drives a fully polar Th2 response in IL-5-deficient animals. A potent IL-10 response is observed irrespective of IL-4 or IL-5 gene status. While MHC Class II knockout animals fail to mount any IL-4 or IL-10 response, the Th2 bias is intact in Class I knockouts, indicating that CD8+ or NK-like T cells restricted to classical or non-classical Class I molecules do not play an essential role in Th2 induction. B cell-deficient microMT animals also show responses, which are strongly skewed to IL-4 production. Thus, Th2 induction by Nippostrongylus antigens is independent of B cells, or MHC class I presentation, and does not require a sufficiency of eosinophils in vivo.

Basophils initiate IL-4 production during a memory T-dependent response

Experiments were performed to characterize and identify the cellular sources of the secondary interleukin (IL)-4 response to a T cell–dependent antigen. Mice were primed by immunization with goat anti–mouse immunoglobulin (Ig)D antibody (GaMD), which stimulates naive CD4⁺ T cells to secrete IL-4 in 3–4 d. When challenged with goat serum 14 d after immunization, GaMD-primed mice generated an IL-4 response that exceeded the primary response by ∼100-fold, started in <2 h, and lasted for 4 d. Studies with 4get mice, in which cells with an accessible Il4 gene express a green fluorescent protein (GFP), revealed CD4⁺ memory T cells, natural killer T cells, basophils, mast cells, and eosinophils as possible rapid producers of IL-4. GFP⁺CD4⁺ T cells and basophils expanded more in the spleen than the other cell types during the primary response to GaMD. Quantitation of in vivo IL-4 production by the in vivo cytokine capture assay after individual cell types were selectively stimulated or deleted demonstrated that basophils and memory CD4⁺ T cells account for most of the secondary IL-4 response, with basophils initiating that response through IgE/FcɛRI-mediated signaling but secreting IL-4 for <4 h and memory T cells secreting IL-4 within 4 h and continuing to secrete this cytokine for 4 d.

Regulatory Effects of Cytokine Production in Atopic Allergic Reaction by Gammi-Danguieumja

Gammi-danguieumja (GD) is clinically used in South Korea for treating atopic dermatitis. However, its effects in experimental models remain unknown. We investigated a possible effect of GD on cytokines production using human T cell line (MOLT-4) or human mast cell line. As a result, GD (0.01 mg/mL)-containing medium in stimulated culture supernatants increased IL-2 and IFN-gamma, and decreased IL-4 secretion in MOLT-4. GD (0.01-1 mg/mL)-containing medium in stimulated culture supernatants dose-dependently and significantly decreased IL-8, IL-13, and tumor necrosis factor-alpha secretion on the phorbol 12-myristate 13-acetate and A23187-stimulated HMC-1. In addition, GD inhibited histamine release from activated mast cells. These results suggest that GD contributes to the regulation of atopic allergic reactions.

Histological aspects and role of mast cells in Helicobacter pylori-infected gastritis

BACKGROUND

Mast cells are one of the main pro-inflammatory cells, while their knowledge in Helicobacter pylori infection has not been summarized.

METHODS

We reviewed studies on mast cells in H. pylori infection, and summarized the histological aspects and roles.

RESULTS

The density of mast cells is greater in H. pylori-infected than in non-infected subjects. Increased mast cell density in infected gastritis significantly decreases after eradication. On electron microscopy, mast cells in infected gastric mucosa show degranulation. Some experimental studies demonstrate that mast cells are degranulated with H. pylori-derived products.

CONCLUSIONS

Mast cells are actively involved in the pathogenesis of H. pylori-infected gastritis. The possible roles are to initiate and promote the formation of oedema through degranulated and secreted mediators, and to release multiple chemotactic factors, which induce inflammatory cells to infiltrate to the site of oedema, showing acute inflammatory changes. Mast cells also stimulate the degradation of pericellular matrices and the growth of cells in their vicinity, and thereby promote tissue turnover. In chronic H. pylori infection, these reactions continue until the bacteria are eradicated. Mast cells may act both to maintain gastritis and to repair tissue damage in H. pylori-infected chronic gastritis.

Type 2 immunity reflects orchestrated recruitment of cells committed to IL-4 production

Using IL-4 reporter mice we identified eosinophils, basophils, and Th2 cells as the three IL-4-producing cell types that appear in the lungs of mice infected with the migrating intestinal helminth, Nippostrongylus brasiliensis. Eosinophils were most prevalent, peaking by approximately 1000-fold on day 9 after infection, with Th2 cells and basophils at 3- and 10-fold lower numbers, respectively. Eosinophil and basophil expansion in blood in response to parasites and their capacity for IL-4 expression required neither Stat6 nor T cells. Th2 induction and expansion in draining lymph nodes was also Stat6 independent. In contrast, eosinophil (and Th2 cell) recruitment to the lung was dependent on Stat6 expression by a bone marrow-derived tissue resident cell, whereas basophil recruitment was Stat6 and IL-4/IL-13 independent but T cell dependent. Primary type 2 immune responses in the lung represent the focal recruitment and activation of discrete cell populations from the blood that have previously committed to express IL-4.

Cytokine expression in allergic inflammation: systematic review of in vivo challenge studies

BACKGROUND

Allergic inflammatory responses are driven by cells of the immune system that rely on cytokines to regulate the activity of other immune and structural cells.

OBJECTIVE

To review published studies to (1) identify cytokines consistently increased after allergen challenge in atopic patients and (2) investigate temporal variation in cytokine expression.

METHODS

A PUBMED systematic search was used to extract data from studies involving analysis of cytokine expression in fluids or biopsies following in vivo allergen challenge in atopic patients.

RESULTS

Data were extracted from 82 studies. There were no consistent reports of cytokine protein increase in fluids of patients at 0-1 h after challenge. At 4-12 h, the chemokines eotaxin, macrophage inflammatory protein-1alpha, RANTES (regulated on activation normal T cell expressed and secreted) and interleukin (IL)-8 have all been consistently reported to be up-regulated. At 18-24 h after challenge, the lymphokines IL-4, IL-5 and IL-13, as well as the pro-inflammatory cytokines granulocyte-macrophage colony-stimulating factor, tumour necrosis factor-alpha and IL-6 are consistently increased when compared with the respective control value. There were no reports of up-regulation in interferon-gamma protein and mRNA and in IL-2 mRNA.

CONCLUSION

The expression of granulocyte-macrophage colony-stimulating factor is consistently increased in tissues at 4-12 h after challenge. The influence of this cytokine on antigen capture and presentation by dendritic cells should be further investigated. Additionally, allergen challenge studies are needed that investigate the expression of macrophage-derived chemokine and thymus-regulated and activation-regulated chemokine in tissues of atopic patients. Blocking the effects of these lymphocyte-specific chemokines might provide new therapeutic approaches for the control of allergic inflammation.

Neutralizing endogenous IL-6 renders mast cells of the MCT type from lung, but not the MCTC type from skin and lung, susceptible to human recombinant IL-4-induced apoptosis

Human cord blood-derived mast cells undergo apoptosis upon exposure to recombinant human (rh)IL-4 and become resistant to rhIL-4-induced apoptosis when cultured in the presence of rhIL-6. The current study extends these effects of rhIL-4 to different populations of human mast cells, namely fetal liver-derived mast cells, lung-derived mast cells, and skin-derived mast cells. Endogenous production of IL-6 appears to protect fetal liver-derived mast cells and those of the MC(T) phenotype from rhIL-4-mediated apoptosis, because neutralization of IL-6 renders these mast cells sensitive. In contrast, mast cells of the MC(TC) phenotype from skin and lung were resistant to IL-4-mediated apoptosis, even after neutralization of endogenous IL-6. MC(TC) cells were CD124(low), whereas those of the MC(T) cells were CD124(high). These observations extend the phenotypic differences between MC(T) and MC(TC) types of human mast cells to include different functional responses to IL-4.

Desferrioxamine modulates chemically induced T helper 2-mediated autoimmunity in the rat

A rise in interleukin (IL) 4-dependent immunoglobulin E (IgE) is a hallmark of the mercuric chloride (HgCl2)-induced Th2-mediated autoimmune syndrome in the Brown Norway (BN) rat, and one of the mediators in allergic asthma in human. Oxidative stress, a potential factor related to the pathogenesis of allergy and asthma, has been shown to up-regulate IL-4 in mast cells and predispose to degranulation in vitro. However, it remains unknown whether oxidative/antioxidative imbalance plays a role in this Th2-driven model of autoimmunity in the rat. Here we show that administration of the non-sulphydryl-containing antioxidant desferrioxamine i.p. and s.c. to BN rats reduces HgCl2-enhanced IL-4 gene expression and inhibits HgCl2-induced Th2-mediated autoimmunity. Desferrioxamine treatment suppresses significantly IgE production and lymphoproliferation, and reduces tissue injury in the form of caecal vasculitis in the HgCl2-induced autoimmune syndrome. These results support a role for oxidative stress in the pathogenesis of the HgCl2-induced Th2-dominated autoimmune syndrome. This finding might have implications for understanding the mechanisms involved in Th2 cell responses as seen in allergy and asthma and thereby aid the development of new therapeutic strategies for these diseases.

A review of experimental studies on diesel exhaust particles and nasal epithelium alterations

The aim of the present review is to summarize biological events in nasal epithelium after short-term exposure to diesel exhaust particles (DEP). Therefore human, animal, and in vitro studies carried out since 1987 are reviewed. Short-term exposure results included qualitative alterations characterized by immediate nasal hyperresponsiveness, antioxidant responses, marked epithelial inflammation, and a specific humoral response. In addition, studies on combined DEP/allergen challenge reported that, besides their intrinsic deleterious properties, DEP produced adjuvant-like effects on the immediate and late-phase response to allergen challenge, since they are able to mimic effects occurring after allergen challenge. DEP act deeply in nasal epithelium by (1) directing cytokine gene expression toward a Th2 profile, (2) enhancing local antigen-specific immunoglobulin E (IgE) production, and (3) driving in vivo isotype switch to IgE. Furthermore, DEP can induce in allergic subjects sensitization to a neoallergen, sensitization that did not occur with exposure to the neoantigen alone. Particulate pollutants such as DEP, encountered in urban areas, are therefore thought to be contributing causal factors to the exaggerated sensitization to allergens in subjects with appropriate genetic predisposition, sensitization that they might not otherwise have experienced. These findings add weight to the hypothesis that DEP are involved in the increased prevalence of airway allergic diseases.

Biology and therapeutic potential of the interleukin-4/interleukin-13 signaling pathway in asthma

The future management of patients with allergic asthma is poised to change in the coming one to two decades. This prediction is based on fundamental new insights into the pathogenesis of disease, gained through the study of both humans and experimental models of asthma. These studies have revealed that allergic asthma is an immune-mediated disease which, despite the redundancy characteristic of all immune responses, may be induced through a single dominant signaling cascade called the interleukin (IL)-4/IL-13 signaling pathway. In addition to the cytokine IL-4, this pathway includes IL-13, the cytokine receptor subunit IL-4 receptor alpha (IL-4Ralpha), Janus-associated tyrosine kinases and the transcription factor, signal transducer and activator of transcription 6. The IL-4 signaling pathway controls the most important cellular developmental (afferent) events that underlie asthma. These include T helper (Th) type 2 cell activation, B cell activation and immunoglobulin (Ig) E secretion, mast cell development, and effector (efferent) events related exclusively to immune effects on the lung such as goblet cell metaplasia and airway hyperresponsiveness. Any of the IL-4 signaling molecules are potentially amenable to pharmacological intervention, but a detailed understanding of the entire pathway is required to appreciate their actual potential for drug development. For example, neutralization strategies that target only IL-4 are unlikely to succeed because they leave IL-13 free to continue the signaling cascade. In contrast, neutralization of IL-4Ralpha may represent a more feasible strategy, as it should prevent signaling by both IL-4 and IL-13. The therapeutic potential of targeting intracytoplasmic tyrosine kinases has already been achieved with the use of small molecules, suggesting that this approach may be realistically adopted for the treatment of asthma. However, well designed asthma clinical trials are warranted to determine with certainty, the efficacy of therapies based on IL-4/IL-13 blockade.

Protein Fv Produced during Viral Hepatitis Is an Endogenous Immunoglobulin Superantigen Activating Human Heart Mast Cells

Protein Fv, an endogenous protein produced in the liver, is released in biological fluids during viral hepatitis. Acute and chronic viral hepatitis can be associated with cardiovascular derangements. Protein Fv induced the release of histamine, tryptase and the de novo synthesis of prostaglandin D(2) and cysteinyl leukotriene C(4) from mast cells isolated from human heart tissue (HHMC). Protein Fv absorbed with protein A-Sepharose coated with polyclonal IgG did not induce histamine secretion. The maximal percent histamine secretion induced by protein Fv correlated (r(s) = 0.60; p < 0.05) with that induced by anti-IgE, whereas there was no correlation between the release caused by proteins Fv and C5a. Preincubation of HHMC with protein Fv or anti-IgE caused complete cross-desensitization to subsequent challenge with heterologous stimulus. HHMC from which IgE had been dissociated no longer released histamine in response to anti-IgE and protein Fv. A human monoclonal IgE blocked both anti-IgE- and protein Fv-induced release. Three human monoclonal IgM V(H)3(+) inhibited protein-Fv-induced secretion of histamine from HHMC, whereas monoclonal IgM V(H)6(+) did not inhibit the release induced by protein Fv. Protein Fv acts as an endogenous immunoglobulin superantigen by interacting with the V(H)3 domain of IgE to induce the release of mediators from HHMC.