Immune response modulation by allergen loaded into mesenchymal stem cell-derived exosomes as an effective carrier through sublingual immunotherapy

•Sublingual immunotherapy is considered as a safe alternative for subcutaneous immunotherapy.•Mesenchymal stem cell-derived exosomes are interesting nanoparticle-based delivery systems with immunomodulatory potential.•Allergen-loaded mesenchymal stem cell-derived exosomes could effectively ameliorate allergic inflammation through sublingual immunotherapy. Allergen-specific sublingual immunotherapy (SLIT) was considered an interesting needle-free alternative for subcutaneous immunotherapy (SCIT). Mesenchymal stem cell (MSC)-derived exosomes were introduced as potent nanoscale delivery systems with immunomodulatory potentials. The current study investigated the therapeutic efficacy of SLIT using ovalbumin (OVA)-enriched MSC-derived exosomes formulation in a murine model of allergic asthma. MSCs were harvested from mice adipose tissues. Then, exosomes were isolated, and OVA-loaded exosomes were prepared. Following sensitization, Balb/c mice received therapeutic formulation (10 μg/dose OVA-containing MSC-derived exosomes) twice a week for two months. Serum OVA-specific IgE levels as well as IFN-γ, IL-4, and TGF-β secretions by cultured splenocytes were measured by ELISA. Also, lung tissue underwent histopathologic analysis, and the numbers of inflammatory cells and eosinophils in nasopharyngeal lavage fluid (NALF) were examined. SLIT using OVA-enriched exosomes significantly reduced IgE levels and IL-4 production, while the secretion of IFN-γ and TGF-β were significantly elevated. Also, a decrease was observed in the numbers of total cells and eosinophils in the NALF, and lower levels of perivascular and peribronchiolar inflammation and cellular infiltrations were observed in the lung tissue. SLIT using OVA-loaded exosomes improved immunomodulatory responses and efficiently alleviated allergic inflammation.