Presence of celiac disease epitopes in modern and old hexaploid wheat varieties:

Presence of celiac disease epitopes in modern and old hexaploid wheat varieties: 
wheat breeding may have contributed to increased prevalence of celiac disease

van den Broeck et al. 2010

Gluten proteins from wheat can induce celiac disease (CD) in genetically susceptible individuals. Specific gluten peptides can be presented by antigen presenting cells to glutensensitive T-cell lymphocytes leading to CD. During the last decades, a significant increase has been observed in the prevalence of CD. This may partly be attributed to an increase in awareness and to improved diagnostic techniques, but increased wheat and gluten consumption is also considered a major cause.

To analyse whether wheat breeding contributed to the increase of the prevalence of CD, the authors have compared the genetic diversity of gluten proteins for the presence of two CD epitopes (Glia-α9 and Glia-α20) in 36 modern European wheat varieties and in 50 landraces representing the wheat varieties grown up to around a century ago. Glia-α9 is a major (immunodominant) epitope that is recognized by the majority of CD patients. The minor Glia-α20 was included as a technical reference. Overall, the presence of the Glia-α9 epitope was higher in the modern varieties, whereas the presence of the Glia-α20 epitope was lower, as compared to the landraces. This suggests that modern wheat breeding practices may have led to an increased exposure to CD epitopes. On the other hand, some modern varieties and landraces have been identified that have relatively low contents of both epitopes. Such selected lines may serve as a start to breed wheat for the introduction of ‘low CD toxic’ as a new breeding trait. Large-scale culture and consumption of such varieties would considerably aid in decreasing the prevalence of CD. As another result the authors found that γ-gliadins also contain various T-cell epitopes that are recognized by groups of patients, although by fewer patients than the α-gliadins.

Currently, there are no specific methods that can recognize the T-cell stimulatory epitopes of the γ-gliadin reliably. New methods are currently being developed, using high throughput sequencing of transcripts and proteomics of gluten proteins. The aim is to qualitatively and quantitatively assess the presence of all CD T-cell stimulatory epitopes in wheat varieties.

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