A novel dendritic cell subset involved in tumor immunosurveillance

Abstract

The interferon (IFN)-γ-induced TRAIL effector mechanism is a vital component of cancer immunosurveillance by natural killer (NK) cells in mice 1,2. Here we show that the main source of IFN-γ is not the conventional NK cell but a subset of B220+Ly6C- dendritic cells, which are atypical insofar as they express NK cell-surface molecules. Upon contact with a variety of tumor cells that are poorly recognized by NK cells, B220+NK1.1+ dendritic cells secrete high levels of IFN-γ and mediate TRAIL-dependent lysis of tumor cells. Adoptive transfer of these IFN-producing killer dendritic cells (IKDCs) into tumor-bearing Rag2-/-II2rg-/- mice prevented tumor outgrowth, whereas transfer of conventional NK cells did not. In conclusion, we identified IKDCs as pivotal sensors and effectors of the innate antitumor immune response. © 2006 Nature Publishing Group.