scholarly journals Germ-free mice exhibit mast cells with impaired functionality and gut homing and do not develop food allergy

2018 ◽  
Author(s):  
Martin Schwarzer ◽  
Petra Hermanova ◽  
Dagmar Srutkova ◽  
Jaroslav Golias ◽  
Tomas Hudcovic ◽  
...  

ABSTRACTBackgroundMucosal mast cells (MC) are key players in IgE-mediated food allergy (FA). The evidence on the interaction between gut microbiota, MC and susceptibility to FA is contradictory.ObjectiveWe tested the hypothesis that commensal bacteria are essential for MC migration to the gut and their maturation impacting the susceptibility to FA.MethodsThe development and severity of FA symptoms was studied in sensitized germ-free (GF), conventional (CV) and mice mono-colonized with L. plantarum WCFS1 or co-housed with CV mice. MC were phenotypically and functionally characterized.ResultsSystemic sensitization and oral challenge of GF mice with ovalbumin led to increased levels of specific IgE in serum compared to CV mice. Remarkably, despite the high levels of sensitization, GF mice did not develop diarrhea or anaphylactic hypothermia, common symptoms of FA. In the gut, GF mice expressed low levels of the MC tissue-homing markers CXCL1 and CXCL2 and harbored fewer MC which exhibited lower levels of MC protease-1 after challenge. Additionally, MC in GF mice were less mature as confirmed by flow-cytometry and reduced edema formation after injection of degranulation-provoking compound 48/80. Co-housing of GF mice with CV mice fully restored their susceptibility to develop FA. However, this did not occur when GF mice were mono-colonized with L. plantarum.ConclusionOur results demonstrate that microbiota-induced maturation and gut-homing of MC is a critical step for the development of symptoms of experimental FA. This new mechanistic insight into microbiota-MC-FA axis can be exploited in the prevention and treatment of FA in humans.

Immunity ◽  
2015 ◽  
Vol 43 (4) ◽  
pp. 788-802 ◽  
Author(s):  
Chun-Yu Chen ◽  
Jee-Boong Lee ◽  
Bo Liu ◽  
Shoichiro Ohta ◽  
Pin-Yi Wang ◽  
...  

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 2660 ◽  
Author(s):  
Yui-Hsi Wang

Immunoglobulin E (IgE)-mediated food allergy is an adverse reaction to foods and is driven by uncontrolled type-2 immune responses. Current knowledge cannot explain why only some individuals among those with food allergy are prone to develop life-threatening anaphylaxis. It is increasingly evident that the immunologic mechanisms involved in developing IgE-mediated food allergy are far more complex than allergic sensitization. Clinical observations suggest that patients who develop severe allergic reactions to food are often sensitized through the skin in early infancy. Environmental insults trigger epidermal thymic stromal lymphopoietin and interleukin-33 (IL-33) production, which endows dendritic cells with the ability to induce CD4+TH2 cell-mediated allergic inflammation. Intestinal IL-25 propagates the allergic immune response by enhancing collaborative interactions between resident type-2 innate lymphoid cells and CD4+TH2 cells expanded by ingested antigens in the gastrointestinal tract. IL-4 signaling provided by CD4+TH2 cells induces emigrated mast cell progenitors to become multi-functional IL-9-producing mucosal mast cells, which then expand greatly after repeated food ingestions. Inflammatory cytokine IL-33 promotes the function and maturation of IL-9-producing mucosal mast cells, which amplify intestinal mastocytosis, resulting in increased clinical reactivity to ingested food allergens. These findings provide the plausible view that the combinatorial signals from atopic status, dietary allergen ingestions, and inflammatory cues may govern the perpetuation of allergic reactions from the skin to the gut and promote susceptibility to life-threatening anaphylaxis. Future in-depth studies of the molecular and cellular factors composing these stepwise pathways may facilitate the discovery of biomarkers and therapeutic targets for diagnosing, preventing, and treating food allergy.


2020 ◽  
Author(s):  
Chinh Tran-To Su ◽  
Wai-Heng Lua ◽  
Jun-Jie Poh ◽  
Wei-Li Ling ◽  
Joshua Yi Yeo ◽  
...  

SUMMARYNickel (Ni) allergy has been reported in contact dermatitis Type IV (Ni-specific T cells mediated) and asthmatic Type I (IgE-mediated) hypersensitivities. Associations between the two hypersensitivities have been found in some patients, but the underlying mechanisms remain enigmatic. Using Her2-specific IgEs as models, we found additional binding to Ni-NTA without observable changes in binding to Her2 and that glutamine, together with the canonical Ni2+-binding histidine, could form Ni2+ binding signatures. This mechanism may underlie Type I hypersensitivity in the selection of anti-Ni2+ IgEs. This mechanism may also underlie Type IV hypersensitivity and the interaction of immunoglobulin proteins with other heavy metal ions. Our findings shed light to how Ni hypersensitivities can occur and how they can be avoided in therapeutics design, or even incorporated for biotechnological purification purposes.


Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1586
Author(s):  
Tomoe Yashiro ◽  
Hanako Ogata ◽  
Syed Faisal Zaidi ◽  
Jaemin Lee ◽  
Shusaku Hayashi ◽  
...  

Recently, the involvement of the nervous system in the pathology of allergic diseases has attracted increasing interest. However, the precise pathophysiological role of enteric neurons in food allergies has not been elucidated. We report the presence of functional high-affinity IgE receptors (FcεRIs) in enteric neurons. FcεRI immunoreactivities were observed in approximately 70% of cholinergic myenteric neurons from choline acetyltransferase-eGFP mice. Furthermore, stimulation by IgE-antigen elevated intracellular Ca2+ concentration in isolated myenteric neurons from normal mice, suggesting that FcεRIs are capable of activating myenteric neurons. Additionally, the morphological investigation revealed that the majority of mucosal mast cells were in close proximity to enteric nerve fibers in the colonic mucosa of food allergy mice. Next, using a newly developed coculture system of isolated myenteric neurons and mucosal-type bone-marrow-derived mast cells (mBMMCs) with a calcium imaging system, we demonstrated that the stimulation of isolated myenteric neurons by veratridine caused the activation of mBMMCs, which was suppressed by the adenosine A3 receptor antagonist MRE 3008F20. Moreover, the expression of the adenosine A3 receptor gene was detected in mBMMCs. Therefore, in conclusion, it is suggested that, through interaction with mucosal mast cells, IgE-antigen-activated myenteric neurons play a pathological role in further exacerbating the pathology of food allergy.


2021 ◽  
Author(s):  
Huaping Xu ◽  
Xiaoyun Shi ◽  
Mengting Xie ◽  
Shiyu Xiao ◽  
Xin Li ◽  
...  

Abstract Background: Denatonium benzoate (DB), one of the bitterest compounds known to man, is currently added to a wide range of products and is also used for alcohol denaturation. Some reports demonstrated that asthmatic symptoms are associated with DB exposure but the possible links between DB and IgE-mediated allergy susceptibility have not been examined to date. We investigated the effects of DB on IgE-mediated mast cell degranulation in vitro and in the ovalbumin (OVA)-induced mouse model of allergy.Methods: DB treatments were given to RBL-2H3 IgE-sensitized rat mast cell/basophil cells and KU812 human basophilic cells together with OVA-induced allergic BALB/c mice. Allergic mediator release, Ca2+ influx and OVA-specific IgE anaphylactic shock symptoms were measured along with the cell-surface expression of the α-subunit of high-affinity IgE receptor FcεRI on mast cells.Results: DB increases β-hexosaminidase (β-hex) release and Ca2+ mobilization in IgE-mediated activated RBL-2H3 and KU812 cells, and enhanced the cell-surface expression of FcεRIα. DB also promoted the severity of OVA-induced anaphylactic and diarrheic symptoms which was accompanied by mucus thickness in jejunum and the levels of β-hex, histamine and OVA-specific IgE in allergy mice, as well as the levels of FcεRIα mRNA and the FcεRIα proteinin isolated mucosal mast cells. Conclusions: DB treatments can promote the IgE-mediated mast cell degranulation in vitro and OVA-induced allergic susceptibility in mice by upregulating mast-cell-surface FcεR1α expression, providing evidence for DB exposure in promoting allergy susceptibility.


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