An Innovative Lateral Flow Device for Dual Detection of Triticeae-derived Prolamins and Avenins

Introduction: Cereal grains contain a composite protein called gluten which consists of prolamins and glutenins. The prolamin fraction from several grains exhibits immunopathogenic potential leading to the manifestation of celiac disease. While the majority of celiac subjects react to wheat, barley, and rye (triticeae), a subset additionally respond to prolamins derived from oats so called avenins. There are differences in the approach to regulating avenins as part of Gluten-Free Labeling. In the USA, oats/avenins are not regarded under labeling legislation, though the celiac community maintains advisory guidelines for oat-containing food products.

Purpose: To develop and validate a highly specific detection kit that can dually and independently detect triticeae- and oat-derived prolamins in under 20 min.

Methods: Monoclonal antibodies (mAbs) against avenin and gliadin were raised in mice using vaccine prepared using a modified Osborne fractionation method to derive pure prolamins from hard red winter wheat and R5(-) oats. An avenin-specific and R5-like clone were characterized and then developed into a rapid assay using lateral flow format. The ensuing kit and test methods were validated.

Results: The Pi Bioscientific Celiac Aide Lateral-flow test method demonstrated a sensitivity for R5(-) avenins and triticeae prolamins (gliadin, hordein, and secalin at 0.5 µg/swab and 5.0 µg/ml each for foods. Specificity analysis revealed no cross-reactivity with common commodities or extracts prepared from soy, lupins, sorghum, corn, rice or millet. Selectivity analysis using a panel of problematic food matrices revealed that the assay was sufficiently robust to enable detection of analyte at levels between 5 - 10 ppm.

Significance: The development of a highly sensitive and rapid test method capable of detecting trace amounts of gliadin, secalin, hordein, and avenin in under 20 min should aid the celiac community and food industry in achieving gluten outcomes that are recommended by the medical community.