QUANTIFICATION IN MASS UNITS OF BET-V-1, THE MAIN ALLERGEN OF BETULA-VERRUCOSA POLLEN, BY A MONOCLONAL-ANTIBODY BASED ELISA

Background Fagales pollens are considered among the main agents respon sible for allergic diseases in many countries of the northern hemisphe re and single major allergens have been shown to be responsible for th ese responses. Objective To develop a solid phase immunoassay for the quantification of Bet v 1, the main allergen from Betula verrucosa (bi rch), and to assess its suitability for quantitating the equivalent ma jor allergen in other Fagales species as well. Methods The assay is ba sed on the use of two different anti-Bet v 1 monoclonal antibodies whi ch were immobilized on the solid phase and, as a primary standard, aff inity purified Bet v 1, the protein content of which was determined by amino acid analysis. Results The ELISA proved to measure less than 0. 2 ng/mL of Bet v 1 with a practical range of 0.4-40 ng/mL and could be suitable to quantify the equivalent major allergen in other Fagales s pecies such as Corylus avellana (hazel), Carpinus betulus (horbeam) an d Alnus glutinosa (alder). The method was compared with quantitative e lectrophoresis and rocket immuno-electrophoresis for the determination of the allergen content in several Betula verrucosa extracts, and a v ery good quantitative correlation was found. Likewise, the Bet v 1 con tent exhibited a good correlation (r=0.87; P<0.005) with the allergeni c potency values obtained by RAST inhibition. Conclusions The results indicate that the Bet v I-assay could be useful for standardization pu rposes in Fagales pollen extracts intended for clinical use.