BACKGROUND AND AIMS: The egg protein ovalbumin (OVA) belongs to six most frequent food allergens. We investigated how thermal processing influences its ability to induce allergic symptoms and immune responses in mouse model of food allergy. METHODOLOGY/PRINCIPAL FINDINGS: Effect of increased temperature (70°C and 95°C) on OVA secondary structure was characterized by circular dichroism and by the kinetics of pepsin digestion with subsequent HPLC. BALB/c mice were sensitized intraperitoneally and challenged with repeated gavages of OVA or OVA heated to 70°C (h-OVA). Levels of allergen-specific serum antibodies were determined by ELISA (IgA and IgGs) or by β-hexosaminidase release test (IgE). Specific activities of digestive enzymes were determined in brush border membrane vesicles of jejunal enterocytes. Cytokine production and changes in regulatory T cells in mesenteric lymph nodes and spleen were assessed by ELISA and FACS. Heating of OVA to 70°C caused mild irreversible changes in secondary structure compared to boiling to 95°C (b-OVA), but both OVA treatments led to markedly different digestion kinetics and Tregs induction ability in vitro, compared to native OVA. Heating of OVA significantly decreased clinical symptoms (allergic diarrhea) and immune allergic response on the level of IgE, IL-4, IL-5, IL-13. Furthermore, h-OVA induced lower activities of serum mast cell protease-1 and enterocyte brush border membrane alkaline phosphatase as compared to native OVA. On the other hand h-OVA stimulated higher IgG2a in sera and IFN-γ secretion by splenocytes. CONCLUSIONS: Minor irreversible changes in OVA secondary structure caused by thermal processing changes both its digestion and antigenic epitopes formation, which leads to activation of different T cell subpopulations, induces shift towards Th1 response and ultimately reduces its allergenicity.

• MeSH
• cytokiny krev   imunologie   MeSH
• imunoglobulin E krev   imunologie   MeSH
• modely nemocí na zvířatech MeSH
• myši MeSH
• ovalbumin chemie   imunologie   MeSH
• potravinová alergie krev   imunologie   MeSH
• prezentace antigenu imunologie   MeSH
• regulační T-lymfocyty imunologie   MeSH
• sekundární struktura proteinů MeSH
• vysoká teplota MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cytokiny MeSH
• imunoglobulin E MeSH
• ovalbumin MeSH

In genetically predisposed individuals, ingestion of wheat gliadin provokes a T-cell-mediated enteropathy, celiac disease. Gliadin fragments were previously reported to induce phenotypic maturation and Th1 cytokine production by human dendritic cells (DCs) and to boost their capacity to stimulate allogeneic T cells. Here, we monitor the effects of gliadin on migratory capacities of DCs. Using transwell assays, we show that gliadin peptic digest stimulates migration of human DCs and their chemotactic responsiveness to the lymph node-homing chemokines CCL19 and CCL21. The gliadin-induced migration is accompanied by extensive alterations of the cytoskeletal organization, with dissolution of adhesion structures, podosomes, as well as up-regulation of the CC chemokine receptor (CCR) 7 on cell surface and induction of cyclooxygenase (COX)-2 enzyme that mediates prostaglandin E2 (PGE₂) production. Blocking experiments confirmed that gliadin-induced migration is independent of the TLR4 signalling. Moreover, we showed that the α-gliadin-derived 31-43 peptide is an active migration-inducing component of the digest. The migration promoted by gliadin fragments or the 31-43 peptide required activation of p38 mitogen-activated protein kinase (MAPK). As revealed using p38 MAPK inhibitor SB203580, this was responsible for DC cytoskeletal transition, CCR7 up-regulation and PGE₂ production in particular. Taken together, this study provides a new insight into pathogenic features of gliadin fragments by demonstrating their ability to promote DC migration, which is a prerequisite for efficient priming of naive T cells, contributing to celiac disease pathology.

• MeSH
• aktivace enzymů účinky léků   MeSH
• biologické modely MeSH
• chemokin CCL19 farmakologie   MeSH
• chemokin CCL21 farmakologie   MeSH
• chemotaxe účinky léků   MeSH
• cyklooxygenasa 2 metabolismus   MeSH
• cytoskelet účinky léků   metabolismus   MeSH
• dendritické buňky cytologie   účinky léků   enzymologie   MeSH
• dinoproston biosyntéza   MeSH
• gliadin farmakologie   MeSH
• lidé MeSH
• MAP kinasový signální systém účinky léků   MeSH
• mitogenem aktivované proteinkinasy p38 metabolismus   MeSH
• peptidové fragmenty farmakologie   MeSH
• receptory CCR7 metabolismus   MeSH
• upregulace účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• CCR7 protein, human MeSH Prohlížeč
• chemokin CCL19 MeSH
• chemokin CCL21 MeSH
• cyklooxygenasa 2 MeSH
• dinoproston MeSH
• gliadin MeSH
• mitogenem aktivované proteinkinasy p38 MeSH
• peptidové fragmenty MeSH
• PTGS2 protein, human MeSH Prohlížeč
• receptory CCR7 MeSH

BACKGROUND: Mammals are essentially born germ-free but the epithelial surfaces are promptly colonized by astounding numbers of bacteria soon after birth. The most extensive microbial community is harbored by the distal intestine. The gut microbiota outnumber ~10 times the total number of our somatic and germ cells. The host-microbiota relationship has evolved to become mutually beneficial. Studies in germ-free mice have shown that gut microbiota play a crucial role in the development of the immune system. The principal aim of the present study was to elucidate whether the presence of gut microbiota and the quality of a sterile diet containing various amounts of bacterial contaminants, measured by lipopolysaccharide (LPS) content, can influence maturation of the immune system in gnotobiotic mice. RESULTS: We have found that the presence of gut microbiota and to a lesser extent also the LPS-rich sterile diet drive the expansion of B and T cells in Peyer's patches and mesenteric lymph nodes. The most prominent was the expansion of CD4+ T cells including Foxp3-expressing T cells in mesenteric lymph nodes. Further, we have observed that both the presence of gut microbiota and the LPS-rich sterile diet influence in vitro cytokine profile of spleen cells. Both gut microbiota and LPS-rich diet increase the production of interleukin-12 and decrease the production of interleukin-4. In addition, the presence of gut microbiota increases the production of interleukin-10 and interferon-gamma. CONCLUSION: Our data clearly show that not only live gut microbiota but also microbial components (LPS) contained in sterile diet stimulate the development, expansion and function of the immune system. Finally, we would like to emphasize that the composition of diet should be regularly tested especially in all gnotobiotic models as the LPS content and other microbial components present in the diet may significantly alter the outcome of experiments.

• MeSH
• aktivace lymfocytů MeSH
• buněčná diferenciace MeSH
• cytokiny metabolismus   MeSH
• dieta MeSH
• gnotobiologické modely imunologie   MeSH
• imunitní systém růst a vývoj   mikrobiologie   MeSH
• imunologická tolerance MeSH
• lipopolysacharidy metabolismus   MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• proliferace buněk MeSH
• regulační T-lymfocyty cytologie   imunologie   metabolismus   MeSH
• střeva imunologie   mikrobiologie   MeSH
• střevní sliznice metabolismus   MeSH
• Th1 buňky cytologie   imunologie   metabolismus   MeSH
• Th2 buňky cytologie   imunologie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• cytokiny MeSH
• lipopolysacharidy MeSH

To elucidate the role of innate immune responses in celiac disease, we investigated the effect of gliadin on blood monocytes from patients with celiac disease. Gliadin induced substantial TNF-alpha and IL-8 production by monocytes from patients with active celiac disease, lower levels by monocytes from patients with inactive celiac disease, and even lower levels by monocytes from healthy donors. In healthy donor monocytes gliadin induced IL-8 from monocytes expressing HLA-DQ2 and increased monocyte expression of the costimulatory molecules CD80 and CD86, the dendritic cell marker CD83, and the activation marker CD40. Gliadin also increased DNA binding activity of NF-kappaB p50 and p65 subunits in monocytes from celiac patients, and NF-kappaB inhibitors reduced both DNA binding activity and cytokine production. Thus, gliadin activation of HLA-DQ2(+) monocytes leading to chemokine and proinflammatory cytokine production may contribute to the host innate immune response in celiac disease.

• MeSH
• aktivace makrofágů imunologie   MeSH
• antigen CD83 MeSH
• antigeny CD40 metabolismus   MeSH
• antigeny CD80 metabolismus   MeSH
• antigeny CD86 metabolismus   MeSH
• CD antigeny metabolismus   MeSH
• celiakie imunologie   metabolismus   MeSH
• cytokiny biosyntéza   MeSH
• gliadin metabolismus   MeSH
• HLA-DQ antigeny metabolismus   MeSH
• imunoglobuliny metabolismus   MeSH
• interleukin-8 biosyntéza   MeSH
• lidé MeSH
• membránové glykoproteiny metabolismus   MeSH
• monocyty metabolismus   MeSH
• NF-kappa B metabolismus   MeSH
• peptidové fragmenty MeSH
• průtoková cytometrie MeSH
• TNF-alfa biosyntéza   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• antigeny CD40 MeSH
• antigeny CD80 MeSH
• antigeny CD86 MeSH
• CD antigeny MeSH
• cytokiny MeSH
• gliadin MeSH
• HLA-DQ antigeny MeSH
• HLA-DQ2 antigen MeSH Prohlížeč
• imunoglobuliny MeSH
• interleukin-8 MeSH
• membránové glykoproteiny MeSH
• NF-kappa B MeSH
• peptidové fragmenty MeSH
• TNF-alfa MeSH