Food Allergy In Mice Research Articles

Eppikajutsuto Protects against Food Allergy Induced by Ovalbumin in a Murine Model

Background: Currently, there are no efficient medications available for the prevention and treatment of food allergy (FA). Herbal medicines, including traditional Japanese Kampo medicines (TJKMs), are promising therapeutic drugs. Methods: We screened 18 TJKMs for treatment of FA symptoms in a mouse FA model induced by ovalbumin (OVA). BALB/c mice were sensitized intraperitoneally by an OVA/aluminum hydroxide gel mixture followed by 4 booster doses of oral OVA and FA symptom induction by 50 mg of OVA. TJKMs were orally administered for 28 days from the day of sensitization to the day before FA symptom induction. Evaluated FA symptoms included a decrease in body temperature and allergic diarrhea. Allergic sensitization was determined by plasma OVA-specific IgE levels. Cytokine mRNA levels in mesenteric lymph nodes, plasma mouse mast cell protease-1, and the number of mast cells in the small and large intestines were analyzed. Additionally, the therapeutic effect of the TJKM eppikajutsuto (EJT) on mast cell degranulation was determined in active anaphylaxis and passive cutaneous anaphylaxis models. Results: EJT effectively prevented FA symptoms. Although OVA-specific IgE levels and the intestinal mast cell numbers were not different between the EJT-treated and untreated FA mice, plasma mMcpt1 and IL-4 levels were lower in EJT-treated FA mice than untreated FA mice. EJT could alleviate symptoms in both active and passive anaphylaxis models. Conclusion: EJT prevented OVA-induced FA symptoms in a mouse model, suggesting that EJT might exert its therapeutic activity via IL-4 suppression and the inhibition of mucosal mast cell degranulation.

Oral administration of Clostridium butyricum CGMCC0313-1 inhibits \u03b2-lactoglobulin-induced intestinal anaphylaxis in a mouse model of food allergy

BackgroundProbiotic bacteria can induce immune regulation or immune tolerance in patients with allergic diseases, but the underlying mechanisms are still unclear. There has been a growing interest in the use of beneficial bacteria for allergic diseases recently. This study aimed at exploring whether Clostridium butyricum CGMCC0313-1 (C. butyricum) can reduce β-lactoglobulin(BLG)-induced intestinal anaphylaxis in a murine model of food allergy.MethodsThe preventive and therapeutic effects of oral C. butyricum on anaphylactic symptoms induced via BLG in food allergy mice were investigated. Intestinal anaphylaxis, T helper (Th)-specific cytokines and transcription factors, secretory IgA (sIgA), CD4+ CD25+ Foxp3Treg cell and histopathological alterations were examined.ResultsClostridium butyricum significantly ameliorated intestinal anaphylaxis symptoms in the food allergy mice. sIgA and CD4+ CD25+ Foxp3Treg cell were increased by oral C. butyricum. It also reversed the imbalance of Th1/Th2 andTh17/Treg.ConclusionsClostridium butyricum reduces BLG-induced intestinal anaphylaxis in mice and might be an additional or supplementary therapy for food allergy.

Lactobacillus reuteri induces intestinal immune tolerance against food allergy in mice

The effect of Lactobacillus reuteri against food allergy was investigated in ovalbumin (OVA)-sensitized BALB/c mice. Oral administration with L. reuteri restored the deteriorated profile of enteric flora, and attenuated allergic diarrhoea, mast cell activation, and serum IgE production in allergic mice. The production of signature T helper (Th)1 and 2 cytokines, namely IFN-γ and IL-4, by splenocytes was suppressed by L. reuteri. Concordantly, the intestinal expression of IFN-γ, IL-4, T-bet and GATA3 was down-regulated. However, L. reuteri augmented the expression of IL-10, TGF-β and Foxp3, and the number of IL-10-secreting CD11c+CD103+ mesenteric lymph node (MLN) cells. Furthermore, direct exposure to heat-killed L. reuteri attenuated OVA-induced cell proliferation and IL-2 secretion by MLN cells. These results demonstrate that L. reuteri possesses anti-allergic activities via modulating enteric flora and promoting tolerogenic immune responses, and suggest L. reuteri as a functional probiotic against food allergy.

Protective effect of Bifidobacterium infantis CGMCC313-2 on ovalbumin-induced airway asthma and β-lactoglobulin-induced intestinal food allergy mouse models.

AIMTo determine whether oral administration of Bifidobacterium infantis CGMCC313-2 (B. infantis CGMCC313-2) inhibits allergen-induced airway inflammation and food allergies in a mouse model.METHODSOvalbumin (OVA)-induced allergic asthma and β-lactoglobulin-induced food allergy mouse models were used in this study. Following oral administration of B. infantis CGMCC313-2 during or after allergen sensitization, histopathologic changes in the lung and intestine were evaluated by hematoxylin and eosin (HE) staining. In the allergic asthma mouse model, we evaluated the proportion of lung-infiltrating inflammatory cells. OVA-specific IgE and IgG1 levels in serum and cytokine levels in bronchoalveolar lavage fluid (BALF) were also assessed. In the food allergy mouse model, the levels of total IgE and cytokines in serum were measured.RESULTSOral administration of B. infantis CGMCC313-2 during or after allergen sensitization suppressed allergic inflammation in lung and intestinal tissues, while the proportion of infiltrating inflammatory cells was significantly decreased in the BALF of allergic asthma mice. Moreover, B. infantis CGMCC313-2 decreased the serum levels of total IgE in food allergy mice, and reductions in IgE and IgG1 were also observed in OVA-induced allergic asthma mice. The expression of interleukin-4 (IL-4) and IL-13 in both serum and BALF was suppressed following the administration of B. infantis CGMCC313-2, while an effect on serum IL-10 levels was not observed.CONCLUSIONB. infantis CGMCC313-2 inhibits the secretion of allergen-induced IgE, IL-4 and IL-13, and attenuates allergic inflammation.

Inhibition effect of blunting Notch signaling on food allergy through improving TH1/TH2 balance in mice

BackgroundNotch signaling regulates proliferation, differentiation, and function of dendritic cells, T cells, and mast cells, as well as many other immune cells, which act as important parts in food allergy, Notch signaling may play an important role in food allergy. ObjectiveTo investigate the role of Notch signaling in IgE-mediated food allergy. MethodsAn ovalbumin-induced food allergy mouse model was built (cholera toxin as adjuvant) and Notch signaling was blunted by FLI-06 and MW167, which inhibited Notch receptor–expressing phase and the γ-secretase–affecting phase, respectively. Then food allergy indicators, including levels of serum antibodies, cytokines, and degranulation, were examined. Meanwhile, clinical features, such as vascular permeability changes, intestinal permeability changes, body temperature changes, and symptoms, were also observed. ResultsAfter blunting Notch signaling, the levels of serum ovalbumin specific IgE and IgG1 were decreased significantly, suggesting that blunting Notch signaling inhibited antibody responses. The levels of TH1 cytokines (interferon-γ) were increased significantly, whereas the levels of TH2 cytokines (interleukin-4, -5, and -13) were decreased significantly, suggesting TH2 polarization was suppressed after blunting Notch signaling. The expression of T-bet was significantly increased, whereas the expression of Gata-3 was significantly reduced in both messenger RNA and protein levels, indicating TH2 polarization was inhibited and TH1 polarization was enhanced after blunting Notch signaling. Moreover, allergic clinical features of mice were alleviated after blunting Notch signaling. ConclusionFood allergy was inhibited by blunting Notch signaling through suppressing TH2 polarization, enhancing TH1 cell differentiation and promoting TH1/TH2 balance in mice. Notch signaling plays a key role in IgE-mediated food allergy.

The anti-inflammatory SSEDIKE peptide from Amaranth seeds modulates IgE-mediated food allergy

The in vivo immunomodulatory effect of a bioactive peptide from Amaranthus hypochondriacus grains in an IgE-mediated food allergy mouse model was examined. The synthetic SSEDIKE peptide was orally administered to prevent food allergy. Upon oral challenge with milk allergens we observed an alleviation of hypersensitivity symptoms with negativization of skin test, a significant inhibition of specific IgE and IgG1 secretion, a substantial reduction in the secretion of IL-5 and IL-13 by antigen-stimulated spleen cells and mucosal reduction of transcripts coding for ccl20, gata-3 and nf-kb. In addition tgf-β and foxp3 mRNA levels were up-regulated in jejunum. The charged SSEDIKE peptide from Amaranth inhibited the allergy reaction in a mouse model of food allergy, with suppression of IgE secretion and control of the intestinal inflammation preventing the activation of NF-κB, which might be attributed to the induction of local tolerance.

Induction of Regulatory T Cells as a Novel Mechanism Underlying the Therapeutic Action of Kakkonto, a Traditional Japanese Herbal Medicine, in a Murine Food Allergy Model

Background: The number of patients with food allergy (FA) has dramatically increased. Although satisfactory drug therapies for FA are not available, we have found that kakkonto, a traditional Japanese herbal medicine, suppressed the occurrence of allergic symptoms in an FA mouse model. Thus, we investigated whether kakkonto could regulate the activation and differentiation of T cells in the colon. Methods: BALB/c mice were systemically sensitized and then orally challenged with ovalbumin. FA mice were orally treated with kakkonto. Lamina propria (LP) cells from their colons were isolated and analyzed. Results: Kakkonto significantly reduced the proportion of CD69⁺ cells and the elevated helper T cell type 2-specific transcription factor GATA-3 mRNA expression in the LP CD4⁺ T cells, showing that kakkonto has a suppressive effect on the activation and Th2 differentiation of LP effector CD4⁺ T cells of the FA mouse colon. Furthermore, kakkonto significantly increased the proportion of Foxp3⁺CD4⁺ regulatory T cells in the LP CD4⁺ T cells of the FA mouse colon. Similarly, the number of Foxp3-positive cells was dramatically increased in the colonic mucosa of kakkonto-administered FA mice. However, the pharmacological effect and Foxp3⁺CD4⁺ regulatory T cell-inducing ability of kakkonto were not attenuated by the administration of an anti-CD25 monoclonal antibody in the FA model. Conclusions: The induction of Foxp3⁺CD4⁺CD25^- regulatory T cells in the colon as a novel mechanism underlying the therapeutic action of kakkonto could be utilized for the development of a novel anti-FA drug.

Histone acetyltransferease p300 modulates TIM4 expression in dendritic cells.

TIM4 (T cell immunoglobulin mucin domain molecule-4) plays a critical role in the initiation of skewed T helper (Th) 2 polarization. The factors regulating TIM4 expression are unclear. This study tests a hypothesis that p300 and STAT6 (signal transducer and activator transcription-6) regulates TIM4 expression in dendritic cells (DC). In this study, a food allergy mouse model was developed with ovalbumin (a specific antigen) and cholera toxin (CT; an adjuvant). The chromatin immunoprecipitation assay was performed to evaluate the chromatin changes at TIM4 and STAT6 promoters. The TIM4 expression was evaluated by real time RT-PCR and Western blotting. The results showed that high levels of p300 and TIM4 were detected in the intestinal DCs of mice with intestinal allergy. p300 is involved in the CT-induced TIM4 expression in DCs. p300 interacts with the chromatin at the TIM4 promoter locus in DCs isolated from allergic mice. CT increases p300 expression to regulate STAT6 levels in DCs. STAT6 mediates the CT-induced TIM4 expression in DCs. In conclusion, p300 and STAT6 mediate the microbial product CT-induced TIM4 expression in DCs.

Food allergy in mice is modulated through the thymic stromal lymphopoietin pathway.

BackgroundThymic stromal lymphopoietin (TSLP) is involved in the pathogenesis of allergic reactions in the skin and the lung. Nevertheless, data on the role of TSLP in food allergy are scarce. We explored the role of TSLP in a mouse model with oral sensitization and oral challenge eliciting food allergy.MethodsTSLP receptor (TSLPR)−/− mice and wild type mice were orally sensitized to β-lactoglobulin in presence of cholera toxin (CT) or CT alone. The elicited immune response was characterized in vitro and the mice were subsequently challenged with the antigen. Lymphocytes from various locations in the gut were activated either by the antigen or by CT and assayed for cytokine secretion.ResultsHere we report that TSLPR−/− are less prone to generate food-induced reactions in conjunction with a decreased antigen-specific IgG1, but not IgE response. In addition, mesenteric lymphnode lymphocytes of TSLPR−/− mice were secreting lower quantities of IL-4, IL-5 and IL-10 after in vivo Ag activation, whereas higher numbers of IL-17 secreting cells were observed. Similarly, activation by the Th2-type adjuvant cholera toxin resulted in an increased frequency of IL-12 and IL-17 secreting lamina propria and mesenteric lymphocytes, together with increased production of IL-12 by activated dendritic cells in TSLPR−/− mice.ConclusionsTSLP can be considered as an essential, but not exclusive, mediator for elicitation of food allergy in mice, as well as a potential target for future therapeutic interventions.

Extracellular vesicle–derived protein from Bifidobacterium longum alleviates food allergy through mast cell suppression

The incidence of food allergies has increased dramatically during the last decade. Recently, probiotics have been studied for the prevention and treatment of allergic disease. We examined whether Bifidobacterium longum KACC 91563 and Enterococcus faecalis KACC 91532 have the capacity to suppress food allergies. B longum KACC 91563 and E faecalis KACC 91532 were administered to BALB/c wild-type mice, in which food allergy was induced by using ovalbumin and alum. Food allergy symptoms and various immune responses were assessed. B longum KACC 91563, but not E faecalis KACC 91532, alleviated food allergy symptoms. Extracellular vesicles of B longum KACC 91563 bound specifically to mast cells and induced apoptosis without affecting T-cell immune responses. Furthermore, injection of family 5 extracellular solute-binding protein, a main component of extracellular vesicles, into mice markedly reduced the occurrence of diarrhea in a mouse food allergy model. B longum KACC 91563 induces apoptosis of mast cells specifically and alleviates food allergy symptoms. Accordingly, B longum KACC 91563 and family 5 extracellular solute-binding protein exhibit potential as therapeutic approaches for food allergies.

Antigen exposure in the late light period induces severe symptoms of food allergy in an OVA-allergic mouse model.

The mammalian circadian clock controls many physiological processes that include immune responses and allergic reactions. Several studies have investigated the circadian regulation of intestinal permeability and tight junctions known to be affected by cytokines. However, the contribution of circadian clock to food allergy symptoms remains unclear. Therefore, we investigated the role of the circadian clock in determining the severity of food allergies. We prepared an ovalbumin food allergy mouse model, and orally administered ovalbumin either late in the light or late in the dark period under light-dark cycle. The light period group showed higher allergic diarrhea and weight loss than the dark period group. The production of type 2 cytokines, IL-13 and IL-5, from the mesenteric lymph nodes and ovalbumin absorption was higher in the light period group than in the dark period group. Compared to the dark period group, the mRNA expression levels of the tight junction proteins were lower in the light period group. We have demonstrated that increased production of type 2 cytokines and intestinal permeability in the light period induced severe food allergy symptoms. Our results suggest that the time of food antigen intake might affect the determination of the severity of food allergy symptoms.

Hydrolyzed whey protein prevents the development of food allergy to β-lactoglobulin in sensitized mice

Food allergy is an adverse immune response to dietary proteins. Hydrolysates are frequently used for children with milk allergy. However, hydrolysates effects afterwards are poorly studied. The aim of this study was to investigate the immunological consequences of hydrolyzed whey protein in allergic mice. For that, we developed a novel model of food allergy in BALB/c mice sensitized with alum-adsorbed β-lactoglobulin. These mice were orally challenged with either whey protein or whey hydrolysate. Whey-challenged mice had elevated levels of specific IgE and lost weight. They also presented gut inflammation, enhanced levels of SIgA and IL-5 as well as decreased production of IL-4 and IL-10 in the intestinal mucosa. Conversely, mice challenged with hydrolyzate maintained normal levels of IgE, IL-4 and IL-5 and showed no sign of gut inflammation probably due to increased IL-12 production in the gut. Thus, consumption of hydrolysate prevented the development of clinical signs of food allergy in mice.

Thrombospondin-1 (TSP1)-producing B Cells Restore Antigen (Ag)-specific Immune Tolerance in an Allergic Environment

Restoration of the antigen (Ag)-specific immune tolerance in an allergic environment is refractory. B cells are involved in immune regulation. Whether B cells facilitate the generation of Ag-specific immune tolerance in an allergic environment requires further investigation. This paper aims to elucidate the mechanism by which B cells restore the Ag-specific immune tolerance in an allergic environment. In this study, a B cell-deficient mouse model was created by injecting an anti-CD20 antibody. The frequency of tolerogenic dendritic cell (TolDC) was assessed by flow cytometry. The levels of cytokines were determined by enzyme-linked immunosorbent assay. The expression of thrombospondin-1 (TSP1) was assessed by quantitative real-time RT-PCR, Western blotting, and methylation-specific PCR. The results showed that B cells were required in the generation of the TGF-β-producing TolDCs in mice. B cell-derived TSP1 converted the latent TGF-β to the active TGF-β in DCs, which generated TGF-β-producing TolDCs. Exposure to IL-13 inhibited the expression of TSP1 in B cells by enhancing the TSP1 gene DNA methylation. Treating food allergy mice with Ag-specific immunotherapy and IL-13 antagonists restored the generation of TolDCs and enhanced the effect of specific immunotherapy. In conclusion, B cells play a critical role in the restoration of specific immune tolerance in an allergic environment. Blocking IL-13 in an allergic environment facilitated the generation of TolDCs and enhanced the therapeutic effect of immunotherapy.

Clostridia spp. combat food allergy in mice

Clostridia spp. combat food allergy in mice

Activation of the AhR pathway prevents food allergy in mice

Ovalbumin treatment resulted in a huge influx of leukocytes in the BAL fluid. Treatment with scGOS/lcFOS/pAOS showed a decreasing trend in the total number of leukocytes in the BAL fluid, represented by decreases in the number of macrophages, neutrophils, eosinophils and lymphocyte subsets. Airway hyperresponsiveness was increased in ovalbumin treated animals. However, treatment with scGOS/lcFOS/pAOS did neither suppress the airway hyperresponsiveness nor airway remodeling. Thesefindings suggest that scGOS/lcFOS/pAOSmighthaveapreventive effect on the allergic influxof immunecells found in chronic asthma,however, themodelweusedmightbe toosevere toobserve differences in lung remodeling parameters. These data encouraged us to further investigate theeffects of scGOS/lcFOS/pAOS inamilder chronic asthma model.

Mechanism of food allergy (FA) induction by medium chain triglycerides (MCT). (HYP7P.314)

Abstract Food ingestion generally induces antigen (Ag)-specific tolerance rather than immunity. Consistent with this, induction of IgE-mediated intestinal FA in mice has required either Ag priming through a parenteral route or ingestion of Ag with a potent toxin. In contrast, we recently reported (JACI, 131:442-50, 2013) that Ag-specific, IgE-mediated FA is induced when a protein Ag is ingested with the widely used nutrient, MCT. We also showed that MCT ingestion induces increased epithelial cell expression of the pro-Th2 cytokines TSLP, IL-25 and IL-33. We now report that MCT ingestion, by itself, can induce shock by damaging intestinal epithelium, with a consequent increase in intestinal permeability. In contrast, ingestion of the anionic detergent, sodium dodecyl sulfate, damages intestinal epithelium but does not promote a Th2 response. Both direct MCT induction of intestinal epithelial damage and MCT promotion of a Th2 response and FA to co-ingested egg white are suppressed in mice treated with the lipase inhibitor orlistat, which blocks intestinal triglyceride absorption. Consistent with MCT induction of TSLP, IL-25 and IL-33, treatment with a cocktail of mAbs to these cytokines or their receptors blocks FA induction by ingested MCT plus egg white. Taken together, these observations suggest that MCT must be absorbed to damage epithelial cells and induce the pro-Th2 cytokines that promote FA development; they also provide a potential paradigm for natural FA development.

Insulin-like growth factor 2 enhances regulatory T-cell functions and suppresses food allergy in an experimental model

The functions of regulatory T (Treg) cells are important in immunity, and the regulatory mechanisms of Treg cell activities are not fully understood yet. We sought to investigate the role of insulin-like growth factor (IGF) 2 in the upregulation of Treg cell function. The expression of insulin-like growth factor 2 receptor (IGF2R) on T cells was assessed by using flow cytometry. Treg cell functions were evaluated by assessing the suppressor effect on proliferation of other effector T (Teff) cells. The effect of IGF2 on regulating Treg cell functions were evaluated with a cell-culture model and a food allergy mouse model. Expression of IGF2R was observed in more than 90% of murine and human Treg cells but in less than 10% of effector CD4(+) T cells. Activation of IGF2R and T-cell receptor induced marked Treg cell proliferation and release of TGF-β from Treg cells, which enhanced Treg cell immune suppressor effects on other Teff cell activities and allergic inflammation in the intestine. Activation of IGF2R enhances Treg cell functions in suppressing other Teff cell activities and inhibiting allergic inflammation in the intestine.

Anti-Allergic Role of Cholinergic Neuronal Pathway via α7 Nicotinic ACh Receptors on Mucosal Mast Cells in a Murine Food Allergy Model

The prevalence of food allergy (FA) has increased in developed countries over the past few decades. However, no effective drug therapies are currently available. Therefore, we investigated cholinergic anti-inflammatory pathway as a regulatory system to ameliorate disrupted mucosal immune homeostasis in the gut based on the pathophysiological elucidation of mucosal mast cells (MMCs) in a murine FA model. BALB/c mice sensitized with ovalbumin received repeated oral ovalbumin for the development of FA. FA mice developed severe allergic diarrhea and exhibited enhanced type 2 helper T (Th2) cell immune responses in both systemic immunity and mucosal immunity, along with MMCs hyperplasia in the colon. MMCs were localized primarily in the strategic position of the mucosal epithelium. Furthermore, the allergic symptoms did not develop in p85α disrupted phosphoinositide-3 kinase-deficient mice that lacked mast cells in the gut. Vagal stimulation by 2-deoxy-D-glucose and drug treatment with nicotinic ACh receptor (nAChR) agonists (nicotine and α7 nAChR agonist GTS-21) alleviated the allergic symptoms in the FA mice. Nicotine treatment suppressed MMCs hyperplasia, enhanced MPO and upregulated mRNA expression of Th1 and Th2 cytokines in the FA mice colon. MMCs, which are negatively regulated by α7 nAChRs, were often located in close proximity to cholinergic CGRP-immunoreactive nerve fibers in the FA mice colon. The present results reveal that the cholinergic neuroimmune interaction via α7 nAChRs on MMCs is largely involved in maintaining intestinal immune homeostasis and can be a target for a new therapy against mucosal immune diseases with homeostatic disturbances such as FA.

Targeting a Cross-Reactive Gly m 5 Soy Peptide as Responsible for Hypersensitivity Reactions in a Milk Allergy Mouse Model

BackgroundCross-reactivity between soybean allergens and bovine caseins has been previously reported. In this study we aimed to map epitopes of the major soybean allergen Gly m 5 that are co-recognized by casein specific antibodies, and to identify a peptide responsible for the cross-reactivity.MethodsCow's milk protein (CMP)-specific antibodies were used in different immunoassays (immunoblotting, ELISA, ELISA inhibition test) to evaluate the in vitro recognition of soybean proteins (SP). Recombinant Gly m 5 (α), a truncated fragment containing the C-terminal domain (α-T) and peptides of α-T were obtained and epitope mapping was performed with an overlapping peptide assay. Bioinformatics tools were used for epitope prediction by sequence alignment, and for modelling the cross-recognized soy proteins and peptides. The binding of SP to a monoclonal antibody was studied by surface Plasmon resonance (SPR). Finally, the in vivo cross-recognition of SP was assessed in a mouse model of milk allergy.ResultsBoth α and α-T reacted with the different CMP-specific antibodies. α-T contains IgG and IgE epitopes in several peptides, particularly in the peptide named PA. Besides, we found similar values of association and dissociation constants between the α-casein specific mAb and the different milk and soy components. The food allergy mouse model showed that SP and PA contain the cross-reactive B and T epitopes, which triggered hypersensitivity reactions and a Th2-mediated response on CMP-sensitized mice.ConclusionsGly m 5 is a cross-reactive soy allergen and the α-T portion of the molecule contains IgG and IgE immunodominant epitopes, confined to PA, a region with enough conformation to be bound by antibodies. These findings contribute to explain the intolerance to SP observed in IgE-mediated CMA patients, primarily not sensitised to SP, as well as it sets the basis to propose a mucosal immunotherapy for milk allergy using this soy peptide.

CGRP, a neurotransmitter of enteric sensory neurons, contributes to the development of food allergy due to the augmentation of microtubule reorganization in mucosal mast cells.

Neuro-immune interaction in the gut is substantially involved in the maintenance of intestinal immune homeostasis and the pathology of intestinal immune diseases. We have previously demonstrated that mucosal mast cells and nerve fibers containing CGRP, a neurotransmitter of intrinsic enteric sensory neurons, are markedly increased and exist in close proximity to each other in the colon of food allergy (FA) mice. In the present study, a CGRP-receptor antagonist BIBN4096BS significantly alleviated allergic symptoms in the murine FA model. In addition, the elevated numbers of mucosal mast cells in the proximal colon of FA mice were significantly decreased in that of BIBN4096BS-treated FA mice. Thus, we investigated the effects of CGRP on calcium-independent process in degranulation of mucosal mast cells since CGRP increases intracellular cAMP levels, but not Ca(2+) concentration. CGRP did not alter a calcium ionophore A23187-increased cytosolic Ca(2+) concentration in mucosal-type bone marrow-derived mast cells (mBMMCs), but did augment microtubule reorganization in resting and A23187-activated mBMMCs. Furthermore, CGRP alone failed to cause the degranulation of mBMMCs, but CGRP significantly enhanced the degranulation of mBMMCs induced by A23187. Together, these data indicate that CGRP- enhanced microtubule reorganization augments IgE-independent/non-antigenic stimuli-induced mucosal mast cell degranulation, thereby contributing to the development of FA.