Description
Intravenous Immunoglobulin (IVIg) is widely used as an immunomodulatory therapy. We have recently demonstrated that IVIg protects against airway hyper-reactivity (AHR) and inflammation in mouse models of allergic airway disease (AAD), associated with induction of Foxp3+ regulatory T cells (Treg). Using DEREG (DEpletion of REGulatory T cell) mice, in which endogenous Treg can be ablated with Diphtheria toxin (DTx) treatment, we demonstrate that IVIg generates a de novo population of induced Treg (iTreg) in the absence of endogenous Treg. IVIg-generated iTreg were sufficient for inhibition of ovalbumin-induced AHR in an antigen-driven murine model of AAD. In the absence of endogenous Treg, IVIg failed to confer protection against AHR and airway inflammation. Adoptive transfer of purified IVIg-generated iTreg prior to antigen challenge effectively prevented airway inflammation and AHR in an antigen-specific manner.