The myriad of cellular interactions that ultimately regulate immune responses are mediated by specific ligand-receptor interactions that, in turn, trigger intracellular signaling pathways. Recent advances in basic cellular and molecular immunology have provided a framework for understanding how the immune response is initiated and regulated, integrating different cell types, molecules and signaling pathways. The Keystone meeting will focus on the immunomodulatory capacity of dendritic cells (DC), a critical cell type in immune regulation. Particular emphasis will be placed on the following. • Receptors that play an important function in pathogen recognition by DC as well as receptors involved in DC processes such as cell adhesion, migration and signaling • The potential role of activating and inhibitory ligands and receptors in modulating DC function • The intracellular signaling triggered by these receptors and the mechanism by which they activate or inhibit immune effector functions and determine cellular lifespan • The molecules involved in cross-talk between DC and other cells and tissues • The mechanisms of DC interactions with the tumor microenvironment • The DC regulatory pathways regulating immunity versus tolerance

Upon completion of this meeting, participants should be able to

• demonstrate an understanding of the signaling pathways triggered by anti-microbial recognition by the surface and intracellular pattern recognition receptors;
• examine how signaling through pattern recognition receptors shapes the effector function of dendritic cells in dictating the type of innate and adaptive immune responses;
• discuss the mechanisms by which DCs induce and maintain central and peripheral tolerance;
• discuss the application of dendritic cell biology in the development of immunotherapy/vaccine for human diseases.