Are DCs actin up?
Philip L. McCarthy ROSWELL PARK CANCER INSTITUTE Geyeregger and colleagues demonstrate that liver X receptor agonists can down-regulate human dendritic cell activation of T cells at the level of the immune synapse. G. B. Shaw’s play, A Doctor’s Dilemma, honored the concepts of phagocytosis (large-particle endocytosis) and opsonization (antibody/antigen binding) described by Metchnikoff and Ehrlich, winners of the 1908 Nobel Prize in Medicine.1 One theme of Shaw’s 1906 play was that the proper use of phagocytosis and opsonization would cure disease. Medicine was focused on the control and eradication of infectious microbes in the preantibiotic era. Nearly 100 years later, the modern-day phagocytes, dendritic cells (DCs), are important regulators of the antigen-specific immune response. There are 2 major types of human DCs: lymphoid and myeloid. DC antigen processing and cell surface expression result in major histocompatibility complex (MHC) class I and class II restricted antigen respo
