Mouse natural killer T (NKT) cells are innate immune cells that express both the NK1.1 antigen and the T cell receptor (TCR) and are abundant in the liver. Once activated by IL-12 or an anti-CD3 antibody (Ab), they produce cytokines and exert antitumor cytotoxicity3,4. Their TCRs are mainly encoded by the Vα14Jα18 and Vβ8 genes5,6. The gene arrangement for encoding the TCR is invariant, and therefore, they are also known as invariant NKT (iNKT) cells. The functions of NKT cells have been examined under stimulation with alpha-galactosylceramide (α-GalCer), a specific sphingoglycolipid ligand of these cells7.