Mucosal targeting of allergen-loaded microspheres by Aleuria aurantia lectin

Murine intestinal M-cells express α-l-fucose residues. We constructed α-l-fucose-targeting particles for oral immunotherapy of IgE-mediated allergy. Poly(d,l-lactic-co-glycolic acid)-microspheres were loaded with birch pollen allergens, and functionalised with the α-l-fucose specific Aleuria aurantia lectin (AAL). The AAL-microspheres had a size of 1–3 μm, protected the entrapped allergens from gastric degradation and released 46.6 ± 1.3% allergen over 21 days in vitro. Oral gavages of AAL-particles to naïve BALB/c mice induced birch pollen-specific IgG2a, but not IgG1 antibodies. We conclude that targeting allergens to α-l-fucose-receptor bearing cells using AAL-microspheres induces specific Th1-antibody responses possibly counteracting Th2-dominated allergy, and therefore provides a potentially useful formulation for oral immunotherapy.