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Isoforms of atopic allergens with reduced allergenicity but conserved T cell antigenicity: possible use for specific
F Ferreira1, K Hirthenlehner, P Briza
1Institute of Genetics and General Biology, University of Salzburg, Austria.
Background:
We analyzed the T cell activation potency and the IgE-binding 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 immunoblot experiments and skin prick tests. The potency of Bet v 1 isoallergens 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 experiments, Bet v 1 isoforms can be grouped into high-IgE-binding molecules 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 birch-pollen-allergic individuals. In contrast, isoform a and natural Bet v 1 displayed high allergenicity in vivo. On the other hand, Bet v 1 isoform d (low allergenicity) displayed significant higher T cell activation potency when compared to isoform a (high allergenicity).
Conclusion:
Based on these findings, we propose a new form of specific immunotherapy using hypoallergenic recombinant allergen isoforms.