Differences in lipopolysaccharide-induced signaling between conventional dendritic cells and macrophages

Dendritic cells (DCs) and macrophages contribute to the activation of immune responses against infectious agents. They sense the presence of microbes through germline-encoded pattern-recognition receptors (PRRs), which recognize pathogen-associated molecular patterns (PAMPs). Among the different PAMPs, the response to lipopolysaccharide (LPS) is one of the best characterized. Upon LPS encounter DCs undergo an activation process and acquire the ability to prime both natural killer and T-cell responses after migration to lymph nodes. Once they completed the effector phase, DCs reach a terminal differentiation stage and eventually die by apoptosis. By contrast, macrophages do not leave the tissue upon LPS recognition. They first initiate inflammatory processes and then switch to an anti-inflammatory phenotype to restore tissue homeostasis. In this review we will focus on the molecular bases of the divergent responses of DCs and macrophages to LPS.