Hypoallergenic derivatives of the major birch pollen allergen Bet v 1 obtained by rational sequence reassembly.
BACKGROUND
At least 100 million patients suffer from birch pollen allergy.


OBJECTIVE
Rational design of recombinant derivatives of the major birch pollen allergen, Bet v 1, characterized by reduced IgE reactivity, preservation of sequences relevant for the induction of allergen-specific blocking IgG, and maintenance of T-cell epitopes for immunotherapy of birch pollen allergy.


METHODS
Three recombinant mosaic proteins derived from Bet v 1 were generated by reassembly of codon-optimized genes coding for Bet v 1 fragments containing the elements for the induction of allergen-specific blocking IgG antibodies and the major T-cell epitopes. The proteins were expressed in Escherichia coli as recombinant mosaic molecules and compared with the Bet v 1 wild-type protein by chemical and structural methods, regarding IgE-binding and IgG-binding capacity, in basophil activation assays and tested for the in vivo induction of IgG responses.


RESULTS
Three recombinant Bet v 1 (rBet v 1) mosaic proteins with strongly reduced IgE reactivity and allergenic activity were expressed and purified. Immunization with the recombinant hypoallergens induced IgG antibodies that inhibited IgE reactivity of patients with allergy to Bet v 1 comparable to those induced with the rBet v 1 wild-type allergen.


CONCLUSIONS
We report the generation and preclinical characterization of 3 hypoallergenic rBet v 1 derivatives with suitable properties for immunotherapy of birch pollen allergy.
Campana
Raffaela
R
Division of Immunopathology, Department of Pathophysiology, Center of Pathophysiology, Infectiology and Immunology, Vienna General Hospital (AKH), Medical University of Vienna, Vienna, Austria.
Vrtala
Susanne
S
Maderegger
Bernhard
B
Jertschin
Peter
P
Stegfellner
Gottfried
G
Swoboda
Ines
I
Focke-Tejkl
Margarete
M
Blatt
Katharina
K
Gieras
Anna
A
Zafred
Domen
D
Neubauer
Angela
A
Valent
Peter
P
Keller
Walter
W
Spitzauer
Susanne
S
Valenta
Rudolf
R
D000818:Animals; D052179:Antigens, Plant / Q000737:chemistry / Q000276:immunology*; D029662:Betula / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D018984:Epitopes, T-Lymphocyte / Q000737:chemistry / Q000276:immunology; D006801:Humans; D007167:Immunotherapy / Q000379:methods; D010940:Plant Proteins / Q000138:chemical synthesis* / Q000737:chemistry / Q000276:immunology*; D011058:Pollen / Q000276:immunology; D011817:Rabbits; D011994:Recombinant Proteins / Q000138:chemical synthesis* / Q000737:chemistry / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology
D052179:Antigens, Plant; D018984:Epitopes, T-Lymphocyte; D010940:Plant Proteins; D011994:Recombinant Proteins; C061312:Bet v 1 allergen, Betula