Dendritic Cell Cross Talk with Innate and Innate-like Effector Cells in Antitumor Immunity: Implications for DC Vaccination

Dendritic cells (DCs) are key players in the induction of immune responses. Adoptive transfer of autologous mature DCs loaded with tumor-associated antigens is a promising therapy for the treatment of immunogenic tumors. For a long time, its therapeutic activity was thought to depend solely on the induction of tumor-specific CD8(+) and CD4(+) T cell responses. More recently, DCs were shown to bidirectionally interact with innate and innate-like immune cells, including natural killer (NK), invariant natural killer T (iNKT), and gamma delta T cells. These effector cells can amplify responses induced by DCs via several mechanisms, including induction of DC maturation and conventional T cell priming. In addition, NK, iNKT, and gamma delta T cells possess cytolytic activity and can act directly on tumor cells. Therapeutic strategies targeting these innate and innate-like immune cells hence hold potential to improve current DC vaccination protocols.