Protection against the allergic airway inflammation depends on the modulation of spleen dendritic cell function and induction of regulatory T cells in mice.

Background: Allergen-induced imbalance of specific T regulatory (Treg) cells and T helper 2 cells plays a decisive role in the development of immune response against allergens.

Objective: To evaluate effects and potential mechanisms of DNA vaccine containing ovalbumin (OVA) and Fc fusion on allergic airway inflammation.

Methods: Bronchoalveolar lavage (BAL) levels of inflammatory mediators and leukocyte infiltration, expression of CD11c+CD80+ and CD11c+CD86+ co-stimulatory molecules in spleen dendritic cells (DCs), circulating CD4+ and CD8+ T cells, Foxp3+ in spleen CD4+ T cells and spleen CD4+ T cells were measured in OVA-sensitized and challenged animals pretreated with pcDNA, OVA-pcDNA, Fc-pcDNA, and OVA-Fc-pcDNA.

Results: OVA-Sensitized and challenged mice developed airway inflammation and Th2 responses, and decreased the proliferation of peripheral CD4+and CD8+ T cells and the number of spleen Foxp3+ Treg. Those changes with increased INF-gamma production and reduced OVA-specific IgE production were protected by the pretreatment with OVA-Fc-pcDNA.

Conclusion: DNA vaccine encoding both Fc and OVA showed more effective than DNA vaccine encoding Fc or OVA alone, through the balance of DCs and Treg.