IL-10 signaling in dendritic cells is required for tolerance induction in a murine model of allergic airway inflammation.

Allergen specific tolerance induction efficiently ameliorates subsequent allergen induced inflammatory responses. The underlying regulatory mechanisms have been attributed mainly to interleukin (IL)-10 produced by diverse hematopoietic cells, while targets of IL-10 in allergen specific tolerance induction have not yet been well defined. Here, we investigate potential cellular targets of IL-10 in allergen specific tolerance induction using mice with a cell type specific inactivation of the IL-10 receptor gene. Allergic airway inflammation was effectively prevented by tolerance induction in mice with IL-10 receptor (IL-10R) deficiency in T or B cells. Similarly, IL-10R on monocytes/macrophages and/or neutrophils was not required for tolerance induction. In contrast, tolerance induction was impaired in mice that lack IL-10R on dendritic cells: those mice developed an allergic response characterized by a pronounced neutrophilic lung infiltration, which was not ameliorated by tolerogenic treatment. In conclusion, our results show that allergen specific tolerance can be effectively induced without a direct impact of IL-10 on cells of the adaptive immune system, and highlight dendritic cells, but not macrophages nor neutrophils, as the main target of IL-10 during tolerance induction.