Selective capture of most celiac immunogenic peptides from hydrolyzed gluten proteins

The available immunomethods for gluten quantitation could underestimate or overestimate the net immunoactivity of foods and beverages if the chosen analytical antibody is not specific to the relevant gluten immunogenic peptides (GIP). Accurate detection of the most active GIP is desirable to assess the potential celiac toxicity of food. We evaluated the capacity of the G12 monoclonal antibody for selectively depleting GIP in samples from two different gluteomes. Samples of hydrolyzed gliadin from wheat and a barley beer were used. The input (starting peptide digest of prolamins), the flow-through (unbound peptides), and the output (captured peptides) were analyzed by G12 and R5 competitive ELISA as well as by stimulation assays of T-cells from celiac patients. Most of the GIP were retained by the G12-agarose and represented the largest part of the immunogenicity of the gluten peptidome. G12 immunodepletion experiments with hydrolyzed gluten showed that this antibody reacted with those with the highest immunoactivity for celiac patients.