A sensitive monoclonal-antibody-based test for gluten detection: Quantitative immunoassay



An enzyme-coupled monoclonal antibody has been used to quantify “gliadin-like immunoreactivity” in a variety of foods. Small discs of nitrocellulose are soaked in food extract or a series of standard gliadin solutions, and incubated with antibody and an enzyme substrate yielding a soluble product. By use of a photometer, standard curves for gliadin may be constructed and the apparent gliadin content of samples calculated. The reproducibility and reliability of the procedure were examined using a variety of common foods and food proteins. The limit of detection for wheat gliadin was approximately 20μg/ml extract; gliadin levels in excess of this value were found in some “gluten-free bread mixes” and starch sources. The overall time for analysis is 5–6 h, although for large numbers of samples, overnight blocking of non-specific antibody binding may be used. It is possible that a “library” of enzyme-linked monoclonal antibodies could be developed as useful tools for specific food analysis.