ISOFORMS OF ATOPIC ALLERGENS WITH REDUCED ALLERGENICITY BUT CONSERVEDT-CELL ANTIGENICITY - POSSIBLE USE FOR SPECIFIC IMMUNOTHERAPY

Background: We analyzed the T cell activation potency and the IgE-bind ing properties (allergenicity) of nine isoforms of Bet v 1, the major allergen of birch pollen. Methods: The capacity of recombinant Bet v 1 isoforms to bind serum IgE from allergic patients was evaluated by im munoblot experiments and skin prick tests. The potency of Bet v 1 isoa llergens to activate T lymphocytes from birch-pollen-allergic patients was assayed using allergen-specific T cell clones. Results: According to their ability to bind IgE from allergic patients in immunoblot exp eriments, Bet v I isoforms can be grouped into high-lgE-binding molecu les and molecules with low/no IgE-binding activity. Representatively, isoform d was used in skin tests. Skin prick tests revealed no potency of this isoform to induce wheal and flare reactions in the skin of bi rch-pollen-allergic individuals. In contrast, isoform a and natural Be t v 1 displayed high allergenicity in vivo. On the other hand, Bet vl isoform d (low allergenicity) displayed significant higher T cell acti vation potency when compared to isoform a (high allergenicity). Conclu sion: Based on these findings, we propose a new form of specific immun otherapy using hypoallergenic recombinant allergen isoforms.