Expansion of Lung Vα14 NKT Cells by Administration of α‐Galactosylceramide‐pulsed Dendritic Cells

NKT cells, a novel murine lymphoid lineage bearing an invariant T cell receptor encoded by Val4 and Ja281 gene segments, recognize a specific ligand glycolipid, α-galactosylceramide (a-GalCer) in a CD1d-dependent manner. Recent research has revealed that activated Val4 NKT cells have dramatic antitumor effects against a wide variety of tumor cell lines in vivo and in vitro. Here, we demonstrate strong in vivo antitumor effects brought about by treatment with α-GalCer-pulsed dendritic cells in comparison with in vitro-activated Vα14 NKT cells. Furthermore, we show a significant expansion of endogenous Vα14 NKT cells in the lung following the administration of α-GalCer-pulsed dendritic cells. The feasibility of immunotherapy with α-GalCer-pulsed dendritic cells is discussed.