Reactivity of gluten detecting monoclonal antibodies to a gliadin reference material.

People affected by coeliac disease need to adhere to a life-long gluten-free diet to avoid symptoms. ELISA-tests are seen as the mainstay for the detection of gluten in gluten-free food because of their sensitivity. They can, however, yield different gluten amounts depending on the antibody and reference material used. We compared the reactivity of three prominent mouse anti-gliadin-antibodies to a reference gliadin isolated from 28 common bred European wheat varieties. The reference material proteins were labelled with fluorescent dye Cy3. They were then separated by 2DE and transferred by Western blot onto low fluorescent PVDF-membranes, followed by incubation with the three primary anti-gliadin antibodies one by one. Detection of the reacting proteins used anti-mouse antibody which was labelled with fluorescent dye Cy5. The use of this technique made it possible to co-detect the 2DE-image of the reference material proteins (Cy3) and proteins reacting with the respective antibody (Cy5). The three investigated antibodies had dissimilar reactivities with different proteins of the reference gliadin. Antibodies R5 and PN3 reacted mainly with gliadin fractions, antibody 401.21 mainly with high molecular weight glutenins. The results confirm the individual specificity of these antibodies and demonstrate the importance of validating immunochemical methods for gluten detection.