Preliminary indications regarding the safety and efficacy potential of allergen bearing bioparticles as an evolved form of immunotherapy

RATIONALE: Antigens represented in a geometrically repetitive 3D pattern are known to elicit a strong immune response. The development of an allergen bearing bioparticle should enhance immunogenicity and may possibly lessen the risk of allergenic reaction expected of the corresponding allergen in its soluble monomeric form.

METHODS: Plant-based transient expression of the fusion of a synthetic non-immunogenic carrier with an allergen component was used to develop allergen bearing bioparticles as a new vector for allergen specific immunotherapy. Bioparticles harboring spikes of oligomerized major dust mite allergen are used here for illustration. These bioparticles were purified, characterized and used for a head-to-head mouse immunogenicity and allergenicity study in comparison with the same allergen in a soluble form and whole dust mite commercial extracts. The ability of these bioparticles to induce degranulation of human basophils derived from house dust mite allergic individuals was also studied.

RESULTS: In a continuum of pre-clinical studies, two injections of allergen-bearing bioparticles were shown to induce a powerful IgG2a immunogenic response and yet without a significant impact on bronchial resistance in a murine model. Strikingly, allergen bearing bioparticles did not induce degranulation of basophils derived from human volunteers allergic to the allergen.

CONCLUSIONS: Our current results suggest that plant-made allergen-bearing bioparticles, by virtue of their high immunogenicity and low allergenicity have the potential to substantially improve the safety and efficacy of future allergy therapeutics.