Dendritic cells: activation and maturation--applications for cancer immunotherapy

There is an increasing number of studies utilizing dendritic cell (DC) based therapies for cancer. With a powerful antigen-presentation capability, DCs have the potential to overcome tumor tolerance and induce anti-tumor immunity, when loaded with tumor antigens. In order to optimize this approach, methods have aimed to enhance immunopotency of therapeutic DCs. A thorough understanding of DC immunobiology would accelerate this process and provide advantageous procedures to increase anti-tumor responses. This review contains an analysis of recent advances on DC subsets, phenotypic characterization, localization, surface receptors and their ligands. The events of immune induction via DCs, involving initial recognition and uptake of antigens, migration, subsequent activation and maturation are revisited. Furthermore, the current methods used for DC-based cancer immunotherapy, including DCs pulsed with tumor antigens in forms of DNA, RNA, peptides, proteins and lysates, or DCs fused with tumor cells are summarized. Respective preclinical and clinical trials are in progress and hold promise for developing effective cancer vaccines.