Isoforms of atopic allergens with reduced allergenicity but conserved T cell antigenicity: possible use for specific immunotherapy.
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).


CONCLUSIONS
Based on these findings, we propose a new form of specific immunotherapy using hypoallergenic recombinant allergen isoforms.
Ferreira
F
F
Institute of Genetics and General Biology, University of Salzburg, Austria.
Hirthenlehner
K
K
Briza
P
P
Breiteneder
H
H
Scheiner
O
O
Kraft
D
D
Breitenbach
M
M
Ebner
C
C
D000485:Allergens / Q000276:immunology*; D052179:Antigens, Plant; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D007167:Immunotherapy; D008213:Lymphocyte Activation; D010940:Plant Proteins / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
D000485:Allergens; D052179:Antigens, Plant; D010940:Plant Proteins; C061312:Bet v 1 allergen, Betula; D007073:Immunoglobulin E