Fig. 5. CTL-mediated activation of iNKT cells strengthens the effector function of CTLs.

a OT-1 cells were cocultured with OVA_257–264-unloaded or -loaded CD1d^KO DCs in the presence or absence of iNKT cells. After 12 h of stimulation, the indicated blocking monoclonal antibodies were added, and the cells were incubated for another 24 h. The levels of IFN-γ in OT-1 cells were examined using intracellular FACS analysis. b Equal numbers of Ly5.1⁺Ly5.2⁺CD1d^WT OT-1 and Ly5.2⁺Ly5.2⁺CD1d^KO OT-1 CD8⁺ T cells were mixed and stimulated with K^bOVA in the presence or absence of iNKT cells. After 2 days of stimulation, the levels of IFN-γ in OT-1 cells were determined using intracellular FACS analysis. b MFI of the intracellular IFN-γ levels of CD1d^WT OT-1 or CD1d^KO OT-1 cells gated on Ly5.1⁺ (CD1d^WT OT-1) or Ly5.1⁻ (CD1d^KO OT-1) Vα2⁺CD8⁺ T cells. All data are representative of at least three independent experiments. Data are presented as the mean ± SEM. *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001. One-way ANOVA with Bonferroni’s multiple comparison test was used for statistical analysis