Regulatory role of iNKT cells in T1D in humans and mice Regulatory role of iNKT cells in T1D in humans and mice. iNKT cells modulate effector T-cell response by cytokine production and cell-contact mechanisms. Regulatory role of iNKT cells in T1D in humans and mice. iNKT cells modulate effector T-cell response by cytokine production and cell-contact mechanisms. In humans, IL-13 produced by iNKT cells inhibits IL-2 production and the proliferation of effector T cells (A). In mouse models, iNKT cells induce similar effector T-cell modulation in a cell-contact–dependent manner (B). Cytokines also play a role by promoting a shift toward Th2 profile (C). Moreover, mouse studies show that iNKT cells promote Treg cell expansion by interacting with DCs that become tolerogenic (D). Similarly, in humans, iNKT cells favor regulatory function of myeloid cells (E); however, this remains to be investigated in the context of T1D physiopathology (in gray). GM-CSF, granulocyte-macrophage colony-stimulating factor; IFNγ, interferon-γ; PD-1, programmed cell death protein 1; PD-L2, programmed cell death protein 1 ligand 2; TGF-β, transforming growth factor-β. Isabelle Nel, and Agnes Lehuen Diabetes 2016;65:2121-2123 ©2016 by American Diabetes Association