IL-33 drives polyfunctionality and antitumor activity of a unique ST2+ NK cell population
Despite increasing recognition of NK cell diversity, their functional heterogeneity and its relevance to cancer remain incompletely understood. Here, we show that IL-12 promotes the emergence of a distinct ST2/IL33R+ NK cell state poised for robust activation by IL-33. Human ST2 NK cells exhibit a unique transcriptional program, an intermediate differentiation state between CD56bright and CD56dim NK cells, and enhanced polyfunctionality combining proliferation, cytokine production, and cytotoxicity. ST2 NK cells were identified across human and murine tumor datasets. In murine breast cancer models, IL-33 and IL-12 cooperated to elicit potent antitumor responses dependent on IFN-{gamma} and ST2 NK cells. In cancer patients, IL-12 unleashed tumor-infiltrating ST2 NK cells' potential to produce IFN-g in response to IL-33, an IL33hi-NKhi score was associated with prolonged survival, and ST2 NK cells correlated with improved immunotherapy response. Collectively, these findings identify ST2 NK cells as a therapeutically actionable NK cell state promoting antitumor immunity.