Transforming growth factor-β promotes the postselection thymic development and peripheral function of interferon-γ-producing invariant natural killer T cells

Interferon-γ producing invariant natural killer T (iNKT1) cells are lipid reactive innate-like lymphocytes that are resident in the thymus and peripheral tissues where they protect against pathogenic infection. The thymic functions of iNKT1 cells are not fully elucidated but subsets of thymic iNKT cells modulate CD8 T cell, dendritic cell, B cell and thymic epithelial cell numbers or function. Here we show that a subset of thymic iNKT1 cells require transforming growth factor (TGF)-β induced signals for their development and for expression of residency associated adhesion receptors. Liver and spleen iNKT1 cells do not share this TGF-β gene signature but nonetheless TGF-β is required for optimal liver iNKT1 cell function. Our findings provide insight into the heterogeneity of mechanisms guiding iNKT1 cell development in different tissues and suggest a close association between a subset of iNKT1 cells and TGF-β producing cells in the thymus.