Depigmented allergoids reveal new epitopes with capacity to induce IgG blocking antibodies.
BACKGROUND
The synthesis of allergen-specific blocking IgGs that interact with IgE after allergen immunotherapy (SIT) has been related to clinical efficacy. The objectives were to investigate the epitope specificity of IgG-antibodies induced by depigmented-polymerized (Dpg-Pol) allergoids and unmodified allergen extracts, and examine IgE-blocking activity of induced IgG-antibodies.


METHODS
Rabbits were immunized with native and Dpg-Pol extracts of birch pollen, and serum samples were obtained. Recognition of linear IgG-epitopes of Bet v 1 and Bet v 2 and the capacity of these IgG-antibodies to block binding of human-IgE was determined.


RESULTS
Serum from rabbits immunized with native extracts recognised 11 linear epitopes from Bet v 1, while that from Dpg-Pol-immunized animals recognised 8. For Bet v 2, 8 epitopes were recognized by IgG from native immunized animals, and 9 from Dpg-Pol immunized one. Dpg-Pol and native immunized serum did not always recognise the same epitopes, but specific-IgG from both could block human-IgE binding sites for native extract.


CONCLUSIONS
Depigmented-polymerized birch extract stimulates the synthesis of specific IgG-antibodies which recognize common but also novel epitopes compared with native extracts. IgG-antibodies induced by Dpg-Pol effectively inhibit human-IgE binding to allergens which may be part of the mechanism of action of SIT.
R&D Department, Laboratorios LETI S.L., Calle del Sol 5, Tres Cantos, 28760 Madrid, Spain.
M Angeles
MA
López-Matas
Mayte
M
Gallego
Víctor
V
Iraola
Douglas
D
Robinson
Jerónimo
J
Carnés
D000485:Allergens / Q000276:immunology; D000080384:Allergoids; D000818:Animals; D019138:Antibodies, Blocking / Q000276:immunology*; D029662:Betula / Q000276:immunology; D001665:Binding Sites; D000939:Epitopes / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D010936:Plant Extracts / Q000276:immunology*; D011058:Pollen / Q000276:immunology; D011817:Rabbits
D000485:Allergens; D000080384:Allergoids; D019138:Antibodies, Blocking; D000939:Epitopes; D007074:Immunoglobulin G; D010936:Plant Extracts