Purpose: In this work the monoclonal antibody G12, raised against the QPQLPY peptide from a toxic fragment called 33-mer of the gliadin, was used to develop a sandwich enzyme linked immunosorbant assay (ELISA), AgraQuant® Gluten G12 and a lateral flow device (LFD), AgraStrip® Gluten G12.
Methods: Studies were performed on the antibody’s specificity, as well as the limit of detection of the test kits. Common and problematic food matrices, rinse water and swabbing from steel and plastic surfaces were evaluated.
Results: The limit of detection (LOD) of the ELISA test was determined to be 2 ppm gluten, with a quantitation range of 4 to 200 ppm. Spiked samples and processed food samples showed comparable performance with a Mendez R5 ELISA method. The LOD of the lateral flow device was determined to be 5 ppm gluten in spiked commodities. By varying the amount of dilution buffer, it was possible to adjust to cutoff levels of 5, 10 and 20 ppm. When testing rinse water, variation in pH from 5 to 9 did not affect the results.
Significance: During validation of these tests, positive and negative responses to oat varieties were obtained. However, the positive results appear to be a specific reaction of the antibody with the toxic fragment, rather than a non-specific positive signal. This suggests that the G12 antibody may shed light on the debate concerning potential immunotoxicity of oats.