Monoclonal antibody-based competitive assay for the sensitive detection of coeliac disease toxic prolamins

Current immunosorbent assays for gluten detection suffer from a number of drawbacks including lack of specificity (e.g. cross-reaction with coeliac disease non-toxic prolamins, detection of total gluten and not specifically coeliac disease toxic gluten) and an inability to detect quantitatively hydrolysates and prolamins present in rye, barley and, possibly, oats. Additionally, the extraction methods employed involve the use of strong reducing agents that are not compatible with enzyme-linked immunosorbent assay. This work reports on the development of a novel competition assay based on the use of a monoclonal antibody raised against a 19-mer peptide recognised in vivo to be coeliac disease toxic. This assay is specific to those cereal prolamins that exacerbate coeliac disease, is capable of the detection of hydrolysate forms and is compatible with typical extraction agents. The optimal assay format is highly sensitive with a detection limit of 0.128 ppm and good reproducibility is obtained with intra-plate and inter-plate relative standard deviation of 3.21% (n = 6) and 3.57% (n = 3) being obtained, respectively. The reported system is the first of several systems under development that aim to address the drawbacks that current assays suffer and meet the sensitivity requirements outlined by the World Health Organisation and Codex Alimentarius.