Thymic iNKT cells respond to α-GalCer in the periphery in an IL-15Rα-dependent manner. iNKT cells were enriched from the thymus of congenic (CD45.1) WT mice and transferred into a congenic (CD45.2) WT host to seed the periphery. Two days after the cell transfer, mice were injected with α-GalCer to activate iNKT cells in vivo. (A) Representative histogram showing the level of IFN-γ being produced by donor (open histogram) and resident iNKT cells (shaded histogram) in liver of mice that received α-GalCer 2 days after the adoptive transfer. (B) Bar graph of the combined data of IFN-γ⁺ donor (□) and resident () iNKT cells isolated from the liver or spleen of mice stimulated with α-GalCer in vivo. Data are generated from 2 independent experiments; n = 4. (C) Bar graph of the combined data of donor IFN-γ⁺ iNKT cells isolated from the liver of IL-15Rα^−/− (□) and WT () mice. Data are generated from 3 independent experiments; n = 6 for IL-15Rα^−/− host and n = 4 for WT host. Error bars represent SEM. *P < .05.