Immunomodulatory effects of Lactobacillus casei administration in a mouse model of gliadin-sensitive enteropathy

Coeliac disease (CD) is a very common food-sensitive enteropathy, which is triggered by gluten ingestion and is mediated by CD4(+) T cells. In addition, alterations in the intestinal microbiota that is normally involved in the homeostasis of GALT (gut-associated lymphoid tissue) seem to play a role in CD. In accordance with these findings, we previously reported that Lactobacillus casei can induce a strong enhancement of the T cell-mediated response to gliadin without inducing enteropathy. In this study, we analysed the effects of L. casei administration in a mouse model of gliadin-induced villous damage that was recently developed and involves the inhibition of cyclo-oxygenase (COX) activities in gliadin-sensitized HLA-DQ8 transgenic mice. To address the issue, we assessed the weight loss, the intestinal cytokine pattern, the density of CD25(+) cells and morphometry of the gut mucosa. We confirmed that COX inhibition in sensitized mice caused villus blunting, dysregulated expression of tumour necrosis factor (TNF)-α and reduced gliadin-specific IL-2 production. Notably, the administration of probiotic strain induced a complete recovery of villus blunting. This finding was associated with a delay in weight decrease and a recovery of basal TNF-α levels, whereas the numbers of CD25(+) cells and the levels of IL-2 remained unchanged. In conclusion, our data suggest that the administration of L. casei can be effective in rescuing the normal mucosal architecture and GALT homeostasis in a mouse model of gliadin-induced enteropathy.

Small intestinal enteropathy in non-obese diabetic mice fed a diet containing wheat

AIMS/HYPOTHESIS

A deranged mucosal immune response and dietary factors may play an important role in the pathogenesis of type 1 diabetes. The aims of our work were to look for the presence of small intestinal enteropathy in non-obese diabetic (NOD) mice in relation to the presence of wheat proteins in the diet, and to assess their role in the risk of developing diabetes.

METHODS

Female NOD mice were fed a standard or gluten-free diet or a gluten-free diet with the addition of wheat proteins (MGFD). Small intestine architecture, intraepithelial CD3(+) infiltration, epithelial expression of H2-IA, mRNA for IFN-gamma and IL-4 were assessed.

RESULTS

NOD mice fed a standard diet showed reduced villous height, increased intraepithelial infiltration by CD3(+) cells and enhanced expression of H2-IA and IFN-gamma mRNA when compared with mice on the gluten-free diet. The cumulative diabetes incidence at 43 weeks of age was 65% in the latter and 97% in the former (p<0.01). Mice on MGFD also showed increased epithelial infiltration and a higher incidence of diabetes.

CONCLUSIONS/INTERPRETATION

Mice fed a wheat-containing diet showed a higher incidence of diabetes, signs of small intestinal enteropathy and higher mucosal levels of proinflammatory cytokines.

Recombinant human interleukin 10 suppresses gliadin dependent T cell activation in ex vivo cultured coeliac intestinal mucosa

BACKGROUND

Enteropathy in coeliac disease (CD) is sustained by a gliadin specific Th1 response. Interleukin (IL)-10 can downregulate Th1 immune responses.

AIM

We investigated the ability of recombinant human (rh) IL-10 to suppress gliadin induced Th1 response.

PATIENTS AND METHODS

IL-10 RNA transcripts were analysed by competitive reverse transcription-polymerase chain reaction in duodenal biopsies from untreated and treated CD patients, non-coeliac enteropathies (NCE), and controls. CD biopsies were cultured with a peptic-tryptic digest of gliadin with or without rhIL-10. The proportion of CD80+ and CD25+ cells in the lamina propria, epithelial expression of Fas, intraepithelial infiltration of CD3+ cells, as well as cytokine synthesis (interferon gamma (IFN-gamma) and IL-2) were measured. Short term T cell lines (TCLs) obtained from treated CD biopsies cultured with gliadin with or without rhIL-10 were analysed by ELISPOT for gliadin specific production of IFN-gamma.

RESULTS

In untreated CD and NCE, IL-10 RNA transcripts were significantly upregulated. In ex vivo organ cultures, rhIL-10 downregulated gliadin induced cytokine synthesis, inhibited intraepithelial migration of CD3+ cells, and reduced the proportion of lamina propria CD25+ and CD80+ cells whereas it did not interfere with epithelial Fas expression. In short term TCLs, rhIL-10 abrogated the IFN-gamma response to gliadin.

CONCLUSIONS

rhIL-10 suppresses gliadin specific T cell activation. It may interfere with the antigen presenting capacity of lamina propria mononuclear cells as it reduces the expression of CD80. Interestingly, rhIL-10 also induces a long term hyporesponsiveness of gliadin specific mucosal T cells. These results offer new perspectives for therapeutic strategies in coeliac patients based on immune modulation by IL-10.

Recombinant human interleukin 10 suppresses gliadin dependent T cell activation in ex vivo cultured coeliac intestinal mucosa

BACKGROUND

Enteropathy in coeliac disease (CD) is sustained by a gliadin specific Th1 response. Interleukin (IL)-10 can downregulate Th1 immune responses.

AIM

We investigated the ability of recombinant human (rh) IL-10 to suppress gliadin induced Th1 response.

PATIENTS AND METHODS

IL-10 RNA transcripts were analysed by competitive reverse transcription-polymerase chain reaction in duodenal biopsies from untreated and treated CD patients, non-coeliac enteropathies (NCE), and controls. CD biopsies were cultured with a peptic-tryptic digest of gliadin with or without rhIL-10. The proportion of CD80+ and CD25+ cells in the lamina propria, epithelial expression of Fas, intraepithelial infiltration of CD3+ cells, as well as cytokine synthesis (interferon gamma (IFN-gamma) and IL-2) were measured. Short term T cell lines (TCLs) obtained from treated CD biopsies cultured with gliadin with or without rhIL-10 were analysed by ELISPOT for gliadin specific production of IFN-gamma.

RESULTS

In untreated CD and NCE, IL-10 RNA transcripts were significantly upregulated. In ex vivo organ cultures, rhIL-10 downregulated gliadin induced cytokine synthesis, inhibited intraepithelial migration of CD3+ cells, and reduced the proportion of lamina propria CD25+ and CD80+ cells whereas it did not interfere with epithelial Fas expression. In short term TCLs, rhIL-10 abrogated the IFN-gamma response to gliadin.

CONCLUSIONS

rhIL-10 suppresses gliadin specific T cell activation. It may interfere with the antigen presenting capacity of lamina propria mononuclear cells as it reduces the expression of CD80. Interestingly, rhIL-10 also induces a long term hyporesponsiveness of gliadin specific mucosal T cells. These results offer new perspectives for therapeutic strategies in coeliac patients based on immune modulation by IL-10.

An immunodominant DQ8 restricted gliadin peptide activates small intestinal immune response in in vitro cultured mucosa from HLA-DQ8 positive but not HLA-DQ8 negative coeliac patients

BACKGROUND

Studies on intestinal T cell clones from the mucosa of patients with coeliac disease have led to the identification of immunogenic gliadin epitopes. One is HLA-DQ8 restricted, its recognition by T cells being increased by introduction of negatively charged residues operated by tissue transglutaminase.

AIM

To test HLA-DQ8 restricted epitope in both native (QYPSGQGSFQPSQQNPQA) and deamidated (QYPSGEGSFQPSQENPQA) forms in an organ culture system of treated coeliac mucosa from HLA-DQ8 positive and HLA-DQ8 negative patients.

PATIENTS AND METHODS

Jejunal biopsies obtained from 10 patients with coeliac disease (six HLA-DQ8 positive and four HLA-DQ8 negative) were cultured in vitro with a peptic-tryptic digest (PT) of gliadin, or with the native (peptide A) or deamidated (peptide B) peptide. Intraepithelial CD3(+) and lamina propria total CD25(+) and CD3(+)CD25(+) cells were counted, lamina propria intercellular adhesion molecule 1 (ICAM-1) expression was evaluated, as well as that of Fas molecules on epithelial cells.

RESULTS

In HLA-DQ8 positive, but not in HLA-DQ8 negative, coeliacs the density of intraepithelial CD3(+) cells, lamina propria total CD25(+), and CD3(+)CD25(+) cells, as well as expression of ICAM-1 and Fas molecules were significantly increased in biopsies cultured with PT, peptide A, or peptide B compared with biopsies cultured in medium alone.

CONCLUSION

These data show that the DQ8 restricted gliadin peptide is immunogenic only in the intestinal mucosa of HLA-DQ8 positive coeliac patients in both native and deamidated forms.