Prophylactic Intranasal Treatment with Fragments of 1,3-β-Glucanase Olive Pollen Allergen Prevents Airway Inflammation in a Murine Model of Type I Allergy

Abstract

Olive pollen is an important cause of allergy in Mediterranean countries. More than 50% of olive-pollen-allergic patients are sensitized against the 1,3-beta-glucanase Ole e 9. To date, prophylactic and therapeutic treatments using purified recombinant allergens have not been studied in animal models of olive pollen allergy. BALB/c mice were immunized against Ole e 9 combining intraperitoneal injections of the allergen in Al(OH)3 with airway allergen challenges. A prophylactic treatment was performed by intranasal administration of a mixture of the recombinant fragments of the allergen prior to Ole e 9 sensitization. Serum levels of specific IgE, IgG1, IgG2a and IgG2b were measured by ELISA, and total IgE levels by sandwich ELISA. Bronchoalveolar lavage and lungs from mice were collected to study airway inflammation by light microscopy. BALB/c mice immunized against Ole e 9 developed a predominantly Th2-like immune response with allergen-specific immunoglobulin induction and airway inflammation accompanied by the infiltration of eosinophils, lymphocytes, and neutrophils in the lung. Prophylactic treatment by intranasal application of the recombinant fragments of Ole e 9 avoids airway inflammation induced by sensitization with this allergen although the levels of Ole e 9-specific antibodies remain unchanged. Prophylactic intranasal treatment with recombinant fragments of Ole e 9 prevents airway inflammation triggered by immunization to this allergen in a murine model of type I allergy.