IL-33 priming amplifies ATP-mediated mast cell cytokine production

•Brief IL-33 alarmin exposure amplifies ATP-induced mast cell cytokine production.•IL-33 priming of the mast cell ATP response is P2X7 dependent.•Co-administration of IL-33 and ATP enhances eosinophilic and monocytic peritonitis. Inflammatory responses are required to block pathogen infection but can also lead to hypersensitivity and chronic inflammation. Barrier tissues actively release IL-33, ATP, and other alarmins during cell stress, helping identify pathogenic stimuli. However, it is unclear how these signals are integrated. Mast cells are critical initiators of allergic inflammation and respond to IL-33 and ATP. We found that mouse mast cells had a 3–6-fold increase in ATP-induced cytokine production when pre-treated with IL-33. This effect was observed at ATP concentrations