CD1d expression on LCL stimulates iNKT cell effector functions. Human iNKT cells (BM2a.3, J3N.5, and M0) were cultured for 48 hours with LCL loaded with (A) or without (B) αGalCer. LCL were pretreated for 24 hours with (■) or without (□) AM580 and blocking αCD1d antibody (△). IFN-γ secretion by iNKT cells was measured by ELISA performed in triplicate (n = 10). ***P < .001. LCL pulsed with (C) or without (D) αGalCer were pretreated for 72 hours with (■) or without (□) AM580 and cocultured with BM2a.3, J3N.5, and M0 for 6 hours at the indicated effector: target (E:T) ratios. 51Cr killing assays were performed in triplicate, using LCL generated from unrelated tonsil samples (n = 6). *P < .05; **P < .01; ***P < .001.