Bone Marrow-Derived IFN-Producing Killer Dendritic Cells Account for the Tumoricidal Activity of Unpulsed Dendritic Cells

Abstract

The CD11cintB220+NK1.1+CD49+ subset of cells has recently been described as IFN-producing killer dendritic cells (IKDC), which share phenotypic and functional properties of dendritic cells and NK cells. Herein we show that bone marrow-derived murine dendritic cell preparations contain abundant CD11cintB220+NK1.1+CD49+ cells, the removal of which results in loss of tumoricidal activity of unpulsed dendritic cells in vivo. Moreover, following s.c. injection, as few as 5 × 103 highly pure bone marrow-derived IKDC cells are capable of shrinking small contralateral syngeneic tumors in C57BL/6 mice, but not in immunodeficient mice, implying the obligate involvement of host effector cells in tumor rejection. Our data suggest that bone marrow-derived IKDC represent a population that has powerful tumoricidal activity in vivo.