Figure 3.

Influences of ILCs on obesity and insulin resistance. In the healthy state, adipose tissue inflammation is suppressed by IL-5 and IL-13, secreted by ILC2s that contribute to the activation of M2 macrophages and eosinophils. Moreover, the productions of IL-4 and IL-13 from ILC2s also promote Th2 development. The inflammatory condition of adipose tissue in obesity is associated with increased infiltration of M1 macrophages, neutrophils, Th1 and CD8⁺ T cells. Recently, the role of ILC1 s in adipose tissue inflammation has been identified, which are mediated by the secretion of IFN-γ that promote M1 macrophage polarization and ILC2 suppression. ILC, innate lymphoid cell; ILC1, group 1 ILC; ILC2, group 2 ILC; Treg, regulatory T cells; TNF-α, tumor necrosis factor-α.