Mesenchymal Stem Cell-derived Exosome; An Interesting Nanocarrier to Improve Allergen-specific Intranasal Immunotherapy.

Increasing the efficacy of allergen-specific intranasal immunotherapy (INIT) has recently been the main goal of several studies to establish this route as a safe delivery method through mucosal pathways. In this case, the present study evaluated the potential of INIT using ovalbumin (OVA)-loaded mesenchymal stromal/stem cell (MSC)-derived exosomes (Exo-OVA) in an allergic asthma mouse model. Together with control groups, sensitized Balb/c mice underwent intranasal immunotherapy with Exo-OVA (10 μg OVA per dose) for three consecutive weeks. Serum-specific immunoglobulin E (IgE) levels, transforming growth factor-beta (TGF-β), interleukin (IL)-4, and interferon-gamma (IFN-γ) production by cultured spleen cells, lung histopathologic analysis, and nasopharyngeal lavage fluid cellular examinations were then conducted. The results showed that INIT using Exo-OVA significantly increased IFN-γ and TGF-β secretion, while allergen-specific IgE and IL-4 production were dramatically decreased compared to the control group receiving phosphate-buffered saline. In addition, the eosinophil and total cell counts in the nasopharyngeal lavage fluid were reduced, and inflammatory conditions and cell accumulation in lung tissue were ameliorated. In conclusion, the Exo-OVA improved the INIT efficacy compared to free OVA. Therefore, this formulation could be introduced as an effective approach for immunomodulatory purposes with a shorter treatment duration and reduced side effects.