Antitumor cytotoxicity mediated by ligand-activated human V alpha 24 NKT cells

Human V alpha 24 NKT cells bearing an invariant V alpha 24J alpha Q antigen receptor, the counterpart of the murine V alpha 14 NKT cells, are activate d by the specific ligand, alpha-galactosylceramide (alpha-GalCer) in a CD1d -dependent manner. Here, we demonstrate that the alpha-GalCer-activated V a lpha 24 NKT cells exert a potent perforin-dependent cytotoxic activity agai nst a wide variety of human tumor cell lines. In addition, we demonstrate t hat V alpha 24 NKT cells and dendritic cells (DCs) from melanoma patients a re functionally normal, even in the tumor-hearing status. The potential use of alpha-GalCer-activated V alpha 24 NKT cells and/or DCs from patients fo r cancer immunotherapy is discussed.