Mannose targeting of poly(lactic-co-glycolic acid): a promising approach for improving sublingual allergen-specific immunotherapy

OBJECTIVE: One of the most effective treatments for allergic respiratory diseases is allergen-specific sublingual immunotherapy (SLIT). While, mannose targeting has been applied in various immunostimulatory approaches, but it has not been investigated in sublingual allergen-specific immunosuppressive treatment. This study assesses mannose targeting for the ovalbumin (Ova) loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles(NPs). METHODS: The emulsion-solvent evaporation method was employed for the synthesis of PLGA NPs containing Ova, and subsequently they attached to D-mannose. Ova-sensitized mice underwent treatment in different ways: subcutaneous administration of 10 µg Ova, sublingual administration of 5 and 10 µg Ova loaded in PLGA NPs, 5 and 10 µg Ova loaded in mannose-targeted PLGA NPs, 10 µg Ova, and 10 µg Ova loaded in dendritic cell-specific aptamer-attached PLGA NPs. Serum Ova-specific IgE and IgG2a levels, as well as IFN-γ, IL-4, IL-10, and IL-17a levels in the supernatant of Ova-stimulated splenocytes were measured. Splenocyte proliferation was assessed using an MTT assay, and also lung histological examinations, and nasal lavage fluid cell counting were performed. RESULTS: Ova-specific IgE, IL-4, IL-17a levels, eosinophil cell count, and splenocyte proliferation were remarkably reduced in the mice treated with mannose or aptamer targeted NPs compared to other groups. Also, IL-10 and IFN-γ levels were remarkably increased in the targeted NPs groups. CONCLUSION: Our findings indicated that mannose targeting of PLGA NPs could decrease allergen dose and improve immunomodulatory effects of SLIT. However, this approach suggests an effective formulation for SLIT in the mice model, further studies with common allergens are needed for application in humans.