Variable Immunogenic Potential of Wheat: Prospective for Selection of Innocuous Varieties for Celiac Disease Patients via in vitro Approach

Abstract

Celiac Disease (CD) is a multifactorial, autoimmune enteropathy activated by cereal proteins in genetically predisposed individuals carrying HLA DQ2/8 genes. A heterogenous gene combination of the cereal prolamins is documented in different wheat genotypes, which is suggestive of their variable immunogenic potential. In the current study, four wheat varieties (C591, C273, 9D, and K78) identified via in silico analysis were analyzed for immunogenicity by measuring T-cell proliferation rate and levels of inflammatory cytokines (Interferon-γ and Tumor Necrosis Factor-α). Peripheral Blood Mononuclear Cells and biopsy derived T-cell lines isolated from four CD patients in complete remission and two controls were stimulated and cultured in the presence of tissue transglutaminase activated pepsin-trypsin (PT) digest of total gliadin extract from test varieties. The immunogenicity was compared with PBW 621, one of the widely cultivated wheat varieties. Phytohaemagglutinin-p was taken as positive control, along with unstimulated cells as negative control. Rate of cell proliferation (0.318, 0.482; 0.369, 0.337), concentration of IFN- γ (107.4, 99.2; 117.9, 99.7 pg/ml), and TNF- α (453.8, 514.2; 463.8, 514.2 pg/ml) was minimum in cultures supplemented with wheat antigen from C273, when compared with other test varieties and unstimulated cells. Significant difference in toxicity levels among different wheat genotypes to stimulate celiac mucosal T-cells and PBMC's was observed; where C273 manifested least immunogenic response amongst the test varieties analyzed.

An open-label randomised pilot trial on safety of wheat variety C273 in patients with adult celiac disease

“…33 Findings from our in silico and in vitro studies led us to select and cultivate a special crop of this wheat variety (C273) for in vivo testing of immunogenicity. 22 , 23 …”

“…The present randomised pilot study is an in vivo extension of previous in silico (identification of specific allelic variants in α-gliadin region of wheat variety C273 especially CeD eliciting epitopes) 22 and in vitro (reduced potential of wheat variety C273 to stimulate CeD specific T-cells) studies. 23 Patients with CeD in remission on strict GFD for ⩾2 years were subjected to a 28-week graded gluten exposure with wheat variety C273. Patients on GFD acted as controls.…”

“…33 Findings from our in silico and in vitro studies led us to select and cultivate a special crop of this wheat variety (C273) for in vivo testing of immunogenicity. 22,23 The use of circulatory inflammatory markers as predictors of intestinal damage and for monitoring disease activity in CeD is not validated but has been proposed to pre-date the changes in established serological markers (anti-tTG and anti-EMA) and histology. A recent study evaluating the efficacy of non-invasive CeD biomarkers in an Indian population concluded that lower levels of plasma citrulline (<30 µmol/l; normal > 30µmol/l) and higher levels of I-FABP [>1100 pg/ml; normal 535.3 (range 321.9-826.9) pg/ml] were consistent with active CeD.…”

“…22 We then tested these three varieties in vitro for their antigenic peptides using T-cells (derived from duodenal mucosal biopsies) and peripheral blood monocytes (PBMCs) isolated from patients with CeD in remission (on GFD) and reported C273 variety as the least immunogenic. 23 The present randomized pilot trial appraises the innocuous nature of the wheat variety C273 through an in vivo exposure in patients with CeD in remission.…”

The Diverse Potential of Gluten from Different Durum Wheat Varieties in Triggering Celiac Disease: A Multilevel In Vitro, Ex Vivo and In Vivo Approach

“…Based on the above results, it might be possible to deduce that the immune response is significantly less stimulated by Saragolla wheat, compared to what is known in the literature when common wheat varieties or gliadin extracts are used [ 33 , 36 ]. Actually, if we consider the natural history of CD, a celiac patient who is not following a strict gluten-free diet will continue having rises in tTG IgA values until the environmental trigger is eliminated, which is gluten, as an epiphenomenon of the perpetuation of the immune response trigger.…”