Background: Mucosal 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. Objective: We tested the hypothesis that commensal bacteria are essential for MC migration to the gut and their maturation impacting the susceptibility to FA. Methods: The 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. Results: Systemic 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 their functionality was impaired as shown by 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 mice were mono-colonized with L. plantarum. Conclusion: Our 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.
- MeSH
- biologické markery MeSH
- buněčná diferenciace genetika imunologie MeSH
- cytokiny metabolismus MeSH
- degranulace buněk genetika imunologie MeSH
- gnotobiologické modely MeSH
- mastocyty imunologie metabolismus MeSH
- metagenom MeSH
- metagenomika metody MeSH
- mikrobiota * imunologie MeSH
- modely nemocí na zvířatech MeSH
- myši MeSH
- náchylnost k nemoci MeSH
- potravinová alergie etiologie metabolismus patologie MeSH
- RNA ribozomální 16S MeSH
- střevní mikroflóra MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Our previous studies on intranasal tolerance induction demonstrated reduction of allergic responses with different allergen constructs. The underlying mechanisms varied depending on their conformation or size. OBJECTIVE: The aim of the present study was to compare the uptake of two structurally different allergen molecules within the respiratory tract following intranasal application. METHODS: The three-dimensional Bet v 1 (Bv1-Protein) and the T cell epitope peptide of Bet v 1 (Bv1-Peptide) were labelled with 5,6-Carboxyfluorescein (FAM) and their uptake was investigated in lung cells and cells of the nasal associated lymphoid tissue from naive and sensitised BALB/c mice. Phenotypic characterisation of FAM+ lung cells after antigen incubation in vitro and after intranasal application was performed by flow cytometry. Impact of Bv1-Protein and Bv1-Peptide on cytokine profiles and gene expression in vivo or in an alveolar epithelial type II (ATII) cell line were assessed in mono- and co-cultures with monocytes using ELISA and quantitative real-time PCR. RESULTS: Both antigens were taken up preferably by ATII-like cells (ATII-LCs) in naive mice, and by macrophages in sensitised mice. After intranasal application, Bv1-Peptide was taken up faster and more efficiently than Bv1-Protein. In vivo and in vitro experiments revealed that Bv1-Protein induced the transcription of thymic stromal lymphopoietin mRNA while Bv1-Peptide induced the transcription of IL-10 and MCP1 mRNA in ATII-LCs. CONCLUSION AND CLINICAL RELEVANCE: Both tested antigens were taken up by ATII-LCs under steady state conditions and induced different polarisation of the immune responses. These data may have an important impact for the generation of novel and more effective prophylactic or therapeutic tools targeting the respiratory mucosa.
- MeSH
- alergeny metabolismus MeSH
- alergie MeSH
- antigeny rostlinné chemie MeSH
- antigeny metabolismus MeSH
- cytokiny metabolismus MeSH
- dýchací soustava imunologie MeSH
- epitelové buňky cytologie MeSH
- epitopy T-lymfocytární chemie MeSH
- epitopy chemie MeSH
- fenotyp MeSH
- fluoresceiny chemie MeSH
- imunitní systém MeSH
- kvantitativní polymerázová řetězová reakce MeSH
- myši inbrední BALB C MeSH
- myši MeSH
- plicní alveoly cytologie MeSH
- průtoková cytometrie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The main goal in reversing the allergy epidemic is the development of effective prophylactic strategies. We investigated the prophylactic effect of neonatal mother-to-offspring mono-colonization with Bifidobacterium longum ssp. longum CCM 7952 on subsequent allergic sensitization. Adult male and female germ-free (GF) mice were mono-colonized with B. longum, mated and their offspring, as well as age-matched GF controls, were sensitized with the major birch pollen allergen Bet v 1. Furthermore, signaling pathways involved in the recognition of B. longum were investigated in vitro. Neonatal mono-colonization of GF mice with B. longum suppressed Bet v 1-specific IgE-dependent β-hexosaminidase release as well as levels of total IgE and allergen-specific IgG2a in serum compared to sensitized GF controls. Accordingly, Bet v 1-induced production of both Th1- and Th2-associated cytokines in spleen cell cultures was significantly reduced in these mice. The general suppression of Bet v 1-specific immune responses in B. longum-colonized mice was associated with increased levels of regulatory cytokines IL-10 and TGF-β in serum. In vitro, B. longum induced low maturation status of bone marrow-derived dendritic cells and production of IL-10 in TLR2-, MyD88-, and MAPK-dependent manner. Our data demonstrate that neonatal mono-colonization with B. longum reduces allergic sensitization, likely by activation of regulatory responses via TLR2, MyD88, and MAPK signaling pathways. Thus, B. longum might be a promising candidate for perinatal intervention strategies against the onset of allergic diseases in humans.
- MeSH
- alergie prevence a kontrola MeSH
- antigeny rostlinné imunologie MeSH
- Bifidobacterium růst a vývoj MeSH
- cytokiny sekrece MeSH
- gastrointestinální trakt mikrobiologie MeSH
- gnotobiologické modely MeSH
- hexosaminidasy metabolismus MeSH
- imunizace MeSH
- imunoglobulin E krev MeSH
- imunologická tolerance MeSH
- modely nemocí na zvířatech MeSH
- myši inbrední BALB C MeSH
- myši MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
