Figure 4

GO induces the conversion of iNKT cells into cells with a regulatory phenotype. (a) iNKT cells purified from B6 mice were cultured with GO (6.25, 12.5, 25, and 50 μg/ml) for 10 hrs and subsequently stimulated with PMA/ionomycin for 2 hrs. The cells were collected and intracellular IFNγ, IL4, and TGFβ production in iNKT cells was determined by flow cytometry. The mean values ± SD are shown (unpaired two-tailed Student’s t-test; *P < 0.05, **P < 0.01, ***P < 0.001; n = 4 per group in the experiment). (b) Experimental scheme to examine the effect of GO-stimulated iNKT cells in α-GalCer-induced immune responses. (c) iNKT cells purified from B6 mice were stimulated with GO and 6 hrs later these cells were separated from the remaining GO by density-gradient centrifugation using Lympholyte-M. DCs purified from Jα18 KO mice were cultured for 14 hrs with GO-stimulated iNKT cells in the presence of either α-GalCer or vehicle. The cells were collected and intracellular IFNγ production in iNKT cells was determined by flow cytometry. The mean values ± SD are shown (unpaired two-tailed Student’s t-test; **P < 0.01, ***P < 0.001; n = 3 per group in the experiment).