Local nasal immunotherapy: efficacy of Dermatophagoides farinae-chitosan vaccine in murine asthma.

BACKGROUND

Local nasal immunotherapy has been reported to be effective for airway allergic diseases. A biodegradable material, chitosan (CS), has been reported to be safe and effective in allergen delivery. In this study, we tested immunotherapeutic efficiency by intranasal administration of Der f entrapped in CS microparticles to sensitized mice.

METHODS

BALB/c mice were sensitized intraperitoneally with Der f extract absorbed to alum, followed by intranasal treatment with PBS, CS, Der f or Der f-CS nano-vaccine for 6 weeks. The mice were subsequently challenged intranasally with Der f extract for 1 week, and we analyzed their clinical symptoms, antibody expression levels, cytokine levels, T cell proliferation and regulatory T cell numbers.

RESULTS

Mice treated with intranasal Der f-CS nano-vaccine prior to challenge displayed an alleviated spectrum of symptoms including airway hyper-reactivity, lung inflammation and mucus production and had fewer eosinophilic cells in bronchoalveolar lavage fluid (BALF). Interestingly, the cytokine levels in Der f-specific IgE were reduced, but IgA in serum and BALF was increased. We also observed that IL-4 was reduced and IFN-gamma and IL-10 were increased among splenocytes and in BALF, which inhibits Der f-specific T-cell proliferation in splenocytes and increases regulatory T cells in the spleen. However, the mice challenged without intranasal Der f or Der f-CS vaccine treatment developed allergic asthma.

CONCLUSION

Our results illustrate that intranasal administration of Der f-CS nano-vaccine plays roles in immunologic protection in murine allergic asthma by inducing regulatory T cells and Th1-type reaction.