IL-5/13–producing ILC2 induce eosinophilia in response to IL-2 therapy. (A) Quantitation by flow cytometry of ILC2 Ki-67 expression with and without IL-2 treatment. (B) Quantitation of total ILC2 from the indicated strains and tissues, expressed as a fold change from phosphate-buffered saline (PBS)-treated control animals. (C) Fluorescence-activated cell sorter gating of CD4⁺ T cells and ILC2 (lin⁻ CD127⁺ CD25⁺) and expression of IL-5 (Red5) in the strains and tissues indicated after PBS or IL-2 treatment. (D) Quantitation of IL-5⁺ ILC2 in IL-5 reporter (red5 R⁺) and IL-5–deleter animals in VAT, lung, and pancreas. (E) Fluorescence-activated cell sorter gating as in (C) for the lung of IL-5–deleter mice treated with IL-2/anti–IL-2 mAb complex. (F) Quantitation of eosinophils in Red5 reporter heterozygous (Red5 R⁺) or IL-5–deleter animals. (G) Representative fluorescence-activated cell sorter gating (top panels) and quantitation (bottom panel) of VAT ILC2 in control IL-13 reporter animals (YetCre13) or IL-13–deleter (YetCre13 × ROSA-DTA) animals after IL-2 complexes. (H) Quantitation of eosinophils in IL-13 reporter controls (YetCre13) or IL-13–deleter animals. Black line (PBS), gray line (IL-2/mAb). Mean values ± SEM. All data were analyzed by comparison of means using unpaired 2-tailed Student t tests. Data are representative of 3 or more experiments or pooled from 2 to 3 experiments. ns, not significant. *P < .05; **P < .01; ***P < .001.