The CC chemokine receptor-7 ligands 6Ckine and macrophage inflammatory protein-3 beta are potent chemoattractants for in vitro- and in vivo-derived dendritic cells

Dendritic cell migration to secondary lymphoid tissues is critical for Ag p resentation to T cells necessary to elicit an immune response. Despite the importance of dendritic cell trafficking in immunity, at present little is understood about the mechanisms that underlie this phenomenon. Using a nove l transwell chemotaxis assay system, we demonstrate that the CC chemokine r eceptor-7 (CCR7) ligands 6Ckine and macrophage inflammatory protein (MIP)3 beta are selective chemoattractants for MHC class IIhigh B7-2(high) bone ma rrow-derived dendritic cells at a potency 1000-fold higher than their known activity on naive T cells, Furthermore, these chemokines stimulate the che motaxis of freshly isolated lymph node dendritic cells, as well as the egre ss of skin dendritic cells ex vivo. Because these chemokines are expressed in lymphoid organs and 6Ckine has been localized to high endothelial venule s and lymphatic endothelium, we propose that they may play an important rol e in the homing of dendritic cells to lymphoid tissues.