BACKGROUND AND AIMS: Celiac disease (CD) is a chronic inflammatory disorder of the small intestine that is induced by dietary wheat gluten proteins (gliadins) in genetically predisposed individuals. The overgrowth of potentially pathogenic bacteria and infections has been suggested to contribute to CD pathogenesis. We aimed to study the effects of gliadin and various intestinal bacterial strains on mucosal barrier integrity, gliadin translocation, and cytokine production. METHODOLOGY/PRINCIPAL FINDINGS: Changes in gut mucosa were assessed in the intestinal loops of inbred Wistar-AVN rats that were reared under germ-free conditions in the presence of various intestinal bacteria (enterobacteria and bifidobacteria isolated from CD patients and healthy children, respectively) and CD-triggering agents (gliadin and IFN-γ) by histology, scanning electron microscopy, immunofluorescence, and a rat cytokine antibody array. Adhesion of the bacterial strains to the IEC-6 rat cell line was evaluated in vitro. Gliadin fragments alone or together with the proinflammatory cytokine interferon (IFN)-γ significantly decreased the number of goblet cells in the small intestine; this effect was more pronounced in the presence of Escherichia coli CBL2 and Shigella CBD8. Shigella CBD8 and IFN-γ induced the highest mucin secretion and greatest impairment in tight junctions and, consequently, translocation of gliadin fragments into the lamina propria. Shigella CBD8 and E. coli CBL2 strongly adhered to IEC-6 epithelial cells. The number of goblet cells in small intestine increased by the simultaneous incubation of Bifidobacterium bifidum IATA-ES2 with gliadin, IFN-γ and enterobacteria. B. bifidum IATA-ES2 also enhanced the production of chemotactic factors and inhibitors of metalloproteinases, which can contribute to gut mucosal protection. CONCLUSIONS: Our results suggest that the composition of the intestinal microbiota affects the permeability of the intestinal mucosa and, consequently, could be involved in the early stages of CD pathogenesis.

• MeSH
• Bacteria pathogenicity   MeSH
• Bacterial Toxins pharmacology   MeSH
• Bifidobacterium pathogenicity   MeSH
• Celiac Disease etiology   MeSH
• Cytokines biosynthesis   MeSH
• Enterobacteriaceae pathogenicity   MeSH
• Gliadin pharmacokinetics   pharmacology   MeSH
• Germ-Free Life MeSH
• Host-Pathogen Interactions drug effects   MeSH
• Interferon-gamma pharmacology   MeSH
• Rats MeSH
• Permeability MeSH
• Goblet Cells pathology   MeSH
• Intestines microbiology   pathology   MeSH
• Intestinal Mucosa drug effects   metabolism   microbiology   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Bacterial Toxins MeSH
• Cytokines MeSH
• Gliadin MeSH
• Interferon-gamma MeSH

The aim of the study was to compare the phenotype of lymphocyte subpopulations of the GALT (gut-associated lymphatic tissue) in germfree (GF) and conventionally (CV) reared rats, i.e. to analyze the effect of microbial colonization on the development of intestinal lymphocyte subsets. Surface marker characteristics were studied in cell suspensions isolated from Peyer's patches, mesenteric lymph nodes, spleen and the intraepithelial lymphocyte compartment of 2- and 12-month old inbred AVN rats. The pattern of T lymphocyte phenotypes in Peyer's patches, mesenteric lymph nodes and spleen determined by FACS analysis did not reveal differences between GF and CV rats. In contrast, a 2-month conventionalization of GF rats led to substantial changes in the composition of intestinal intraepithelial lymphocyte subsets (IELs): increase of CD4+, CD8 alpha+, CD8 beta+, TcR alpha/beta+ bearing lymphocytes was observed after colonization of rats with normal microflora. Surprisingly, the relative numbers of lymphocytes bearing TcR gamma/delta+ did not change during conventionalization. The effect of aging was also studied and differences in IELs composition of aged (GF) and (CV) rats were found to be more pronounced: 6.6% and 30% of lymphocytes bearing TcR alpha/beta were present among IELs in two-month old GF and CV rats, respectively. 30% of IELs in 2-month old GF rats, 80% of IEL from 12-month old CV rats were found to bear TcR alpha/beta. This finding demonstrates that during conventionalization and aging the TcR alpha/beta bearing population of IELs substantially expands. It suggests that mainly this lymphocyte subset responds to microflora stimuli and is probably involved in the protection of the epithelial cell layer of intestinal mucosa.

• MeSH
• Bacteria growth & development   MeSH
• Germ-Free Life MeSH
• Immunophenotyping MeSH
• Rats, Inbred Strains MeSH
• Rats MeSH
• Lymphoid Tissue immunology   MeSH
• Aging immunology   MeSH
• Intestinal Mucosa immunology   microbiology   MeSH
• T-Lymphocyte Subsets immunology   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH

• MeSH
• Models, Biological * MeSH
• Bone Marrow Cells MeSH
• Germ-Free Life * MeSH
• Hematopoietic Stem Cells cytology   MeSH
• Hematopoietic System growth & development   MeSH
• Rabbits MeSH
• Lymph Nodes cytology   MeSH
• Lymphatic System growth & development   MeSH
• Lymphocytes cytology   MeSH
• Cell Count MeSH
• Swine MeSH
• Spleen cytology   MeSH
• Thymus Gland cytology   MeSH
• Animals MeSH
• Check Tag
• Rabbits MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Comparative Study MeSH