A SANDWICH ENZYME-LINKED-IMMUNOSORBENT-ASSAY (ELISA) FOR THE QUANTITATION OF SELECTED PEANUT PROTEINS IN FOODS

A sandwich-type, enzyme-linked immunosorbent assay (ELISA) was develop ed for the detection of selected peanut proteins in foods. Monoclonal antibodies against a series of allergenic peanut proteins were used as the capture antibody. Food sample extracts were then added, and polyc lonal rabbit antibodies directed against roasted peanut proteins were employed as secondary antibodies. The amount of allergen bound to the solid-phase was determined by a biotin and streptavidin-peroxidase sys tem. Radioallergosorbent assay (RAST) inhibition studies of the food e xtracts were done as a comparison. The coefficient of determination fo r the ELISA and RAST assays was 0.85. Selected food samples were teste d by RAST inhibition at another laboratory for comparison. Skin tests were done with selected samples in peanut-allergic adults, and the res ults correlated to the ELISA and RAST inhibition results. In other stu dies, defatted peanut protein (0.01 to 5.0%) were added to vanilla ice cream, then extracted and analyzed using ELISA and skin tests. The se nsitivity of the ELISA in ice cream was approximately 40 mug/ml. In si x of seven peanut-sensitive adults tested, the lowest level of added p eanut protein (0.01%, 21 mug/ml) still caused a positive skin test rea ction.