Nrp-1 is a marker of RTE iNKT cells. (A-B) Five-week-old mice were intrathymically injected with FITC and their spleens recovered after 36 hours. Splenocytes were enriched in iNKT cells and Nrp-1 expression was analyzed in iNKT cells by FACS. (A) Representative analysis of Nrp-1 and FITC expression in splenic CD1d Tet⁺ iNKT cells of control (No FITC) and treated (Intrathymic FITC) animals. (B) Nrp-1 expression by FITC⁻ and FITC⁺ splenic iNKT cells from treated animals (n = 4, pooled data from 2 distinct experiments, **P < .01 by Student paired t test). (C-D) Eight-week-old mice were thymectomized (Tx) or sham-thymectomized (sTx) and killed 4 weeks later for analysis. (C) Representative FACS analysis of Nrp-1 and CD69 expression in splenic CD1d Tet⁺ CD19⁻ iNKT cells of sTx and Tx mice. (D) Absolute numbers of total, Nrp-1⁺, and Nrp-1⁻ iNKT cells in the spleens of sTx (light gray) and Tx (dark gray) mice (n = 4 for sTx and n = 5 for Tx, pooled data from 2 distinct experiments, ns: not significant, **P < .01 by unpaired Student t test).