Jejunal mucosa lymphoid cell subsets and the expression of major histocompatibility complex antigens in children

Gliadin regulates the NK-dendritic cell cross-talk by HLA-E surface stabilization

We analyzed the autologous NK cell interaction with gliadin-presenting dendritic cells. Gliadin is the known Ag priming the celiac disease (CD) pathogenesis. We demonstrate that gliadin prevents immature dendritic cells (iDCs) elimination by NK cells. Furthermore, cooperation between human NK cells-iDCs and T cells increases IFN-gamma production of anti-gliadin immune response. Gliadin fractions were analyzed for their capability to stabilize HLA-E molecules. The alpha and omega fractions conferred the protection from NK cell lysis to iDCs and increased their HLA-E expression. Gliadin pancreatic enzyme digest and a peptide derived from gliadin alpha increased HLA-E levels on murine RMA-S/HLA-E-transfected cells. Analysis of HLA-E expression in the small intestinal mucosa of gluten-containing diet celiac patients and organ culture experiments confirmed the in vitro data.

Food antigen activates intraepithelial and lamina propria lymphocytes in food-sensitive enteropathy in mice

Morphologic and immunologic changes in the gut mucosa of food-hypersensitive mice, from a study model generated by feeding ovalbumin (OVA) to female BALB/c mice after intraperitoneal injection of cyclophosphamide (CY), were investigated in an effort to clarify the mechanisms of food-sensitive enteropathy. Villous atrophy, crypt hyperplasia, and increased numbers of intraepithelial lymphocytes (IEL) were confirmed in the antigen-challenged OVA-sensitive mice as seen in food-sensitive enteropathy in humans, whereas no significant morphologic changes were observed in the nontreated control group or groups treated with OVA or CY alone. IEL and lamina propria lymphocytes (LPL) were isolated from the intestinal mucosa before and after the antigen challenge, and surface markers were analyzed by FACScan. After the antigen challenge, the numbers of CD8+ cells increased among the IEL, and the occurrence of both CD4+ and CD8+ cells increased among the LPL. The numbers of Thy-1+ cells and TCR- alpha/beta + cells increased among both the IEL and LPL, and LFA-1 expression was enhanced in both of these lymphocyte populations. The proliferative response of IEL and LPL to OVA increased in a dose-dependent manner after the antigen challenge in the OVA-sensitive mouse model. These results indicate that IEL and LPL, possibly those that have migrated from peripheral blood, are activated by orally administered antigens and cause mucosal damage in the food-sensitive enteropathy.

The regulation of intestinal hypersensitivity reactions to ovalbumin by omega-3 fatty acid enriched diet: studies of IEL and LPL in mucosal damage

In order to clarify the mechanisms of food-sensitive enteropathy, a food hypersensitive model was generated by feeding ovalbumin to female BALB/c mice after intraperitoneal injection of cyclophosphamide and morphological and immunological changes in the gut mucosa were investigated. Villus atrophy, crypt hyperplasia and increased numbers of intra-epithelial lymphocytes (IEL) were confirmed in this model, as seen in food-sensitive enteropathy in humans. Subpopulations of IEL and lamina propria lymphocytes were enumerated by immunohistochemical observation. CD8-positive cells were increased both in epithelium and lamina propria, whereas CD4-positive cells were decreased in lamina propria. We document here that orally administered food antigen actually induces food-sensitive enteropathy and mucosal damage is generated by lymphocytes that infiltrate the intestinal mucosa. We also investigated the effect of feeding an omega-3 fatty acid-enriched diet in this model and found that it was efficient in attenuating mucosal damage.