Abstract
Cell signaling pathways regulate much in the life of a cell: from shuttling cargo through intracellular compartments and onto the cell surface, how it should respond to stress, protecting itself from harm (environmental insults or infections), to ultimately, death by apoptosis. These signaling pathways are important for various aspects of the immune response as well. However, not much is known in terms of the participation of cell signaling pathways in Ag presentation, a necessary first step in the activation of innate and adaptive T cells. In this brief review, I discuss the known signaling molecules (and pathways) that regulate how Ags are presented to T cells and the mechanism(s), if identified. Studies in this area have important implications in vaccine development and new treatment paradigms against infectious diseases, autoimmunity, and cancer.