Proliferation and survival of peripheral iNKT cells are supported by DCs via IL-15 transpresentation. (A) The percentage of BrdU⁺ iNKT subsets in the thymus, liver, and spleen of IL-15Rα^−/−, CD11c/IL-15Rα Tg, and WT mice after given BrdU (0.8 mg/mL) supplemented by drinking water for 7 days. Subsets consisted of the various stages of iNKT cell development as defined by CD44 and NK1.1 expression. Data are mean plus or minus SEM, derived from 2 independent experiments: n = 4 for IL-15Rα^−/−, n = 5 for CD11c/IL-15Rα Tg, n = 4 for WT mice. *P ≤ .05. (B) Representative histograms comparing the levels of Bcl-2 expression from NK1.1⁺ subset-derived IL-15Rα^−/− and CD11c/IL-15Rα Tg mice (top 2 panels) or CD11c/IL-15Rα Tg and WT mice (bottom 2 panels) in the various tissues. (C) MFI of Bcl-2 from CD4⁺ or DN NK1.1⁺ subsets isolated from the thymus, liver, and spleen of IL-15Rα^−/−, CD11c/IL-15Rα Tg, and WT mice. Data are mean ± SEM, derived from 3 independent experiments; n = 6 to 8 mice/group. *P ≤ .05.