Interleukin 33 Exacerbates Antigen Driven Airway Hyperresponsiveness, Inflammation and Remodeling in a Mouse Model of Asthma

Interleukin 33 (IL-33) represents a potential link between the airway epithelium and induction of Th2-type inflammatory responses associated with the development of asthma. This study investigated the potential of IL-33 to exacerbate antigen driven asthma responses. An ovalbumin (OVA) asthma model was used in which sensitized C57BL/6 mice were exposed to IL-33 before each OVA challenge. IL-33 given to sensitized mice acted synergistically with antigen and aggravated airway inflammation, hyperresponsiveness and remodeling compared with mice that were only OVA sensitized and challenged and mice that were only exposed to IL-33. Elevated levels of local and systemic mast cell protease mMCP-1, as well as antigen-specific IgE production, were observed following IL-33 administration to sensitized mice. Similarly, exposing OVA-sensitized mice to IL-33 increased the Th2 cytokine levels, including IL-4, IL-5 and IL-13. Furthermore, IL-33 and OVA administration to OVA-sensitized mice increased ILC2s in the lung, suggesting a role for ILC2s in IL-33-mediated exacerbation of OVA-induced airway responses. Collectively, these findings show that IL-33 aggravates important features of antigen-driven asthma, which may have implications for asthma exacerbations.