J. Cancer Mol. 2: 213-215, 2006

[Review Article]

Dendritic Cell, Toll-Like Receptor, and The Immune System

Ko-Jiunn Liu

Institute of Cancer Research, National Health Research Institutes, Taipei, Taiwan

Abstract:

Dendritic cells (DCs) comprise a complex lineage and subset of bone marrow-derived antigen-presenting cells.  DCs not only directly participate in the defense of microbial pathogens in the innate immune system; they also transmit the information of the invading pathogens and present pathogen antigens to T cells of the adaptive immune system and modulate subsequent immune responses.  One critical factor for DCs to discriminate antigens derived from dead tissue cells or pathogens is the co-presence of certain pathogen-associated molecular patterns.   DCs express several pattern-recognition receptors including the toll-like receptors.  DCs use different toll-like receptors to simultaneously detect several features of the pathogens.  Signals generated from various toll-like receptors coordinately regulate the production of distinct cytokines and determine the nature of the resulting immune responses.  Thus, the ligands of toll-like receptors or toll-like receptor agonists are potent stimulators of the immune system.  Several pharmaceutical companies are now exploring the application of toll-like receptor agonists in the treatment of several diseases including cancers.  Preliminary results suggest that this kind of strategy may provide a new direction of immunotherapy.