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 responsible for allergic diseases in many countries of the northern hemisphere and single major allergens have been shown to be responsible for these responses.

OBJECTIVE

To develop a solid phase immunoassay for the quantification of Bet v 1, the main allergen from Betula verrucosa (birch), and to assess its suitability for quantitating the equivalent major allergen in other Fagales species as well.

METHODS

The assay is based on the use of two different anti-Bet v 1 monoclonal antibodies which were immobilized on the solid phase and, as a primary standard, affinity 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 species such as Corylus avellana (hazel), Carpinus betulus (horbeam) and Alnus glutinosa (alder). The method was compared with quantitative electrophoresis and rocket immuno-electrophoresis for the determination of the allergen content in several Betula verrucosa extracts, and a very good quantitative correlation was found. Likewise, the Bet v 1 content exhibited a good correlation (r = 0.87; P < 0.005) with the allergenic potency values obtained by RAST inhibition.

CONCLUSIONS

The results indicate that the Bet v 1-assay could be useful for standardization purposes in Fagales pollen extracts intended for clinical use.