Measurement of canine IgE using the alpha chain of the human high affinityIgE receptor

In vitro assays for allergen specific immunoglobulin E (IgE) are a convenie nt and reproducible alternative to intradermal skin testing in dogs. Such t ests may be used to support a diagnosis of atopic dermatitis and to define appropriate allergens for immunotherapy. Current in vitro assays rely upon monoclonal or polyclonal antibodies as IgE detection reagents. However, in sera where allergen-specific IgG occurs in great excess, any IgE:IgG cross- reactivity of the detection reagent may result in lowered assay specificity . Therefore, we have developed an assay for canine IgE which uses a recombi nant form of the extracellular part of the alpha chain of the human high af finity IgE receptor (Fc epsilon RI alpha), Biotinylated Fc epsilon RI alpha shows no significant binding to purified canine IgG, and recognizes a heat labile antibody in serum, with a detection limit of 73-146 pg/ml. Comparis on of assay signals using the labeled Fc epsilon RI alpha and a highly spec ific anti-canine IgE monoclonal antibody (MAb) shows good agreement. The Fc epsilon RI alpha is therefore a sensitive and specific alternative to poly clonal or monoclonal antibodies for canine serum IgE measurement. (C) 2001 Elsevier Science B.V. All rights reserved.