Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta , Edmonton , Alberta , Canada.
A sensitive double antibody sandwich ELISA (DAS-ELISA) based on chicken anti-gliadin IgY and biotinylated monoclonal antibody (mAb) was developed for the quantification of gliadin in foods. The anti-gliadin IgY and mAb specifically detected gliadin in wheat, barley, and rye by indirect ELISA and Western-blot assay. Using anti-gliadin IgY as capture antibody and biotinylated mAb as detecting antibody, the sensitivity of DAS-ELISA has a linear standard range of 4-40 ng/mL, showing that the limit of detection (LOD) corresponds to 4 ng/mL gliadin in assay buffer, equivalent to 0.8 ppm in foods. The intra-assay expressed as percentage of coefficients of variation (%CV) was 7.25% average of six food samples. The interassay precision was 9.51% in food samples. The combination of anti-gliadin IgY and biotinylated mAb in the DAS-ELISA provides a reliable, sensitive, and inexpensive tool for the detection of gliadin in gluten-free and gluten-containing food products.