Reference Number: 74
Celiac disease is a prevalent disorder characterized by a chronic intestinal inflammation driven by HLA-DQ2 or -DQ8-restricted T cells specific for ingested wheat gluten peptides. The dominant T-cell responses are to epitopes that cluster within a stable 33mer fragment formed by physiologic digestion of distinct alpha-gliadins. Celiac disease is treated by excluding all gluten proteins from the diet. Conceivably, a diet based on baking-quality gluten from a wheat species that expresses no or few T-cell stimulatory gluten peptides should be equally well tolerated by the celiac patients and, importantly, also be beneficial for disease prevention.
To identify baking quality, harmless wheat, we followed the evolution of the wheat back to the species that most likely have contributed the AA, BB, and DD genomes to the bread wheat. Gluten were extracted from a large collection of these ancient wheat species and screened for T-cell stimulatory gluten peptides.
Distinct differences in the intestinal T-cell responses to the diploid species were identified. Interestingly, we found that the fragments identical or equivalent to the immunodominant 33mer fragment are encoded by alpha-gliadin genes on the wheat chromosome 6D and thus absent from gluten of diploid einkorn (AA) and even certain cultivars of the tetraploid (AABB) pasta wheat.
SIGNIFICANCE OF THIS STUDY
The results of the current study suggest that screening of primitive wheat cultivars followed by breeding and selection based on the absence of certain gluten protein sequences has the potential to produce wheat cultivars that are devoid or low in specific protein sequences that may be harmful to patients with celiac disease. The findings from this study may have potential implications for celiac disease because they provide the prospect of identifying and producing wheat species with low or absent levels of harmful gluten proteins using specialised breeding techniques.