Type 2 immunity and metabolism. (A) Metabolic regulation of type 2 immune function. Transcription regulation by PPARγ promotes monocyte M2 polarization and lung CD11b+ DC for Th2 priming. Transcription regulation by PPARδ increases tissue macrophage M2 polarization. Lactic acid also induces tissue macrophage M2 polarization. Fatty acid oxidation promotes germinal B cell reaction. (B) Type 2 immune regulation of metabolic function. IL-4 and its downstream activation of STAT6 inhibit systemic insulin resistance. Type 2 immune activation via IL-33/ILC2 and IL-4/IL-13 responses leads to beige adipose tissue differentiation and lipolysis. IL-13 promotes mitochondrial respiration in muscles.