Nrp-1⁺ RTE iNKT cells proliferate more than Nrp-1⁻ mature iNKT cells after in vitro activation. (A) Proliferation of FACS-sorted splenic Nrp-1⁻ and Nrp-1⁺ iNKT cells after 3 days of in vitro activation with irradiated spleen cells in lymphocyte culture medium alone (Control) or supplemented with α-GalCer. Representative data of 2 distinct experiments. (B) Proliferation of total spleen cells from sham-thymectomized (sTx, light gray) and thymectomized (Tx, dark gray) mice after 2 days of in vitro activation with α-GalCer (n = 3 for sTx and n = 4 for Tx, **P < .01 by unpaired Student t test).