Potential therapy of Fc-antigen combination-encoding DNA vaccination in mouse allergic airway inflammation

Summary Vaccination with allergen-encoding DNA has been proposed as having potential for allergen-specific immunotherapy. In this study, we examine the therapeutic effect of allergen-encoding DNA vaccination directly to dendritic cells (DCs) on allergen-induced allergic airway inflammation in a mouse model and explore potential mechanism. Ovalbumin (OVA)-sensitized and challenged mice were immunized with DNA vaccine and received bronchoalveolar lavage (BAL) 1 day after the last challenge, to measure BAL levels of interleukin (IL)-4, IL-5, interferon (IFN)-gamma and differential cell count. Pulmonary DCs and Spleen DCs were purified and sorted according to the expression of CD11c+CD80+ and CD11c+CD86+ co-stimulatory molecules. Our data demonstrated that DNA vaccine therapy with OVA-Fc-pcDNA3·1 significantly prevented OVA-increased levels of IL-4, IL-5 and the percentage of eosinophils and OVA-decreased level of IFN-gamma. OVA-Fc-pcDNA3·1-treated mice had less severity of airway inflammation, and lower expression of CD11c+CD80+ and CD11c+CD86+ on pulmonary DCs, as compared with animals with OVA-pcDNA3·1, pcDNA3·1 and OVA respectively. DNA vaccine encoding both Fc and OVA was shown to be more effective than DNA vaccine encoding OVA alone. Our data indicate that Fc-antigen combination-encoding DNA vaccination has better preventive effects on antigen-induced airway inflammation by regulating DCs, and may be a new alternative therapy for asthma.