Today, dendritic cells are thus positioned as the master regulators of immunity. Pharmacological intervention to exploit the full range of dendritic cell regulatory potential will undoubtedly lead to a variety of therapeutic applications to either boost, suppress or repolarize the immune system (20, 21). Another recently recognized important function of dendritic cells is to link the innate and adaptive immune response. This is illustrated by antiviral responses of plasmacytoid DCs (22), and by crosstalk between DCs and NK cells (23). A major breakthrough in dendritic cells  biology has been the recent unraveling of the mechanisms responsible for their

regulatory functions, an advance made possible by the molecular cloning of genes expressed by DCs. Thus, it was realized that dendritic cells are remarkably equipped with Pattern -Recognition Receptors (PRRs), the innate sensors that recognize conserved molecular patterns on microbes and self- tissue. Outstanding PRRs are the C- type Lectin Receptors and the Toll - Like Receptors. The key role played by Chemokines and their receptors in the migration patterns of dendritic cells is now well established. Finally, an array of Cytokines and corresponding receptors are known to be responsible for the crosstalk between DCs and a host of other cell types that will determine the net outcome of the immune response. Collectively, this rapidly-evolving knowledge allows for drug-discovery programs to design pharmacological compounds to agonize or antagonize dendritic cell molecules in a number of clinical settings.