Interferon-γ Released by Gluten-Stimulated Celiac Disease-Specific Intestinal T Cells Enhances the Transepithelial Flux of Gluten Peptides

Abstract

Celiac sprue is a T-cell-mediated enteropathy elicited in genetically susceptible individuals by dietary gluten proteins. To initiate and propagate inflammation, proteolytically resistant gluten peptides must be translocated across the small intestinal epithelium and presented to DQ2-restricted T cells, but the effectors enabling this translocation under normal and inflammatory conditions are not well understood. We demonstrate that a fluorescently labeled antigenic 33-mer gluten peptide is translocated intact across a T84 cultured epithelial cell monolayer and that preincubation of the monolayer with media from gluten-stimulated, celiac patient-derived intestinal T cells enhances the apical-to-basolateral flux of this peptide in a dosedependent, saturable manner. The permeability-enhancing activity of activated T-cell media is inhibited by blocking antibodies against either interferon-␥ or its receptor and is recapitulated using recombinant interferon-␥. At saturating levels of interferon-␥, activated T-cell media does not further increase transepithelial peptide flux, indicating the primacy of interferon-␥ as an effector of increased epithelial permeability during inflammation. Reducing the assay temperature to 4°C reverses the effect of interferon-␥ but does not reduce basal peptide flux occurring in the absence of interferon-␥, suggesting active transcellular transport of intact peptides is increased during inflammation. A panel of disease-relevant gluten peptides exhibited an inverse correlation between size and transepithelial flux but no apparent sequence constraints. Anti-interferon-␥ therapy may mitigate the vicious cycle of gluten-induced interferon-␥ secretion and interferon-␥-mediated enhancement of gluten peptide flux but is unlikely to prevent translocation of gluten peptides in the absence of inflammatory conditions.

Selected Probiotic Lactobacilli Have the Capacity To Hydrolyze Gluten Peptides during Simulated Gastrointestinal Digestion

“…It was shown that the use of antibodies to block IFN-␥ not only inhibits the activation of metalloproteinases and the influx of gluten peptides through the intestinal barrier but also deters mucosal injury (48,49). Previously, baked wheat products containing gluten that was hydrolyzed by lactic acid bacteria and fungal proteases during sourdough fermentation did not induce IFN-␥ (19) in vitro, thus yielding products that were safe for CD patients (18).…”

Celiac Disease and Ischemic Heart Disease: What is the Link?

“…IFN-γ has been illustrated as a key determinant in gut permeability as well as in inflammation in CD [8,9]. It has been found that IFN-γ secreted by gluten-activated celiac patient T cells, represents the primary effector of increased gluten peptide translocation during active disease [9]. Toxic gluten peptides have been reported to elicit an important immune response in the celiac intestine after regiospecific deamidation by an endogenous extracellular enzyme, transglutaminase 2 (TG2) [10].…”

“…It has been assessed that the cytokine expression pattern in response to gluten is strongly dominated by Interferon-γ (IFN-γ) and that celiac patients show an increased expression of IFN-γ and a high number of TCD4 + IFN-γ-producing cells [7]. IFN-γ has been illustrated as a key determinant in gut permeability as well as in inflammation in CD [8,9]. It has been found that IFN-γ secreted by gluten-activated celiac patient T cells, represents the primary effector of increased gluten peptide translocation during active disease [9].…”

“…CD has been described as a chronic systemic immune-mediated condition triggered by dietary gluten in genetically susceptible individuals [4]. Gluten-sensitive enteropathy is characterized by villous atrophy, various degrees of crypt cell hyperplasia and increased numbers of intraepithelial lymphocytes of the proximal small intestine [6][7][8][9]. It has been assessed that the cytokine expression pattern in response to gluten is strongly dominated by Interferon-γ (IFN-γ) and that celiac patients show an increased expression of IFN-γ and a high number of TCD4 + IFN-γ-producing cells [7].…”

Coeliac Disease: From Triggering Factors to Treatment

“…Likewise the prevention of the recruitment of lymphocytes targeting the chemokine receptor and ligand interactions e.g. CCR9 and CCL25 [40] and CXCR3 and CXCL10 [41] and the modulation of inflammation by monoclonal antibodies against TNF-α (Infliximab) [42] and IFN-γ [43] are another attractive therapeutic options for CD [44].…”