Characterising Unintended Effects of Genetic Modification on Expression of Gluten Proteins Involved in IgE-Mediated Allergies and Coeliac Disease Using Proteomics

Rationale: Wheat gluten proteins are responsible for triggering coeliac disease (CD) and IgE-mediated allergies and consequently are included in allergenicity risk assessment of novel foods (including GMOs).  Understanding the unintended effects of new technology on gluten protein allergens will support the risk assessment process. Untargeted proteomic profiling approaches have much to offer in understanding such affects.

Methods: A wheat gluten protein database was built with potential coeliac toxicity and IgE-reactivity assessed using in silicoepitope mapping. Gluten proteins were extracted from untransformed and GM wheat lines. Proteomic profiling was performed using data independent analysis. Data were processed and searched against a complete gluten database and additional IgE-mediated allergy proteins.

Results: The distribution of celiac toxic and IgE-epitopes was assessed in different gluten protein sub-types.  The α-gliadins had the highest density of celiac toxic motifs, followed by the γ-gliadins.  Proteomic profiling of wild-type and GM lines showed many gluten proteins not expressed in wheat seeds. Semi-quantitative analysis allowed differences in wild-type and GM lines to be identified with over-expression of HMW subunits of glutenin. Changes observed in expression of wheat gluten proteins and their implications for allergenicity risk assessment process are discussed. 

Conclusions: Proteomic profiling of gluten proteins allows unintended effects of genetic modification to be assessed. Such evidence-based approaches help inform how the benefits of novel foods, including GM and food processing procedures are realised for the population whilst still protecting the allergic consumer.