Dendritic cells are the “shakers and movers” of the immune system. They detect pathogens and then get the immune response rolling by activating T cells. Dendritic cells in the skin and other epithelial surfaces are called Langerhans cells (purple). Like all dendritic cells, Langerhans cells use receptors on their cell surface (e.g., Toll receptors) to identify and uptake pathogens (red) by phagocytosis or endocytosis. Once triggered, Langerhans cells then emigrate from the epithelia into the blood or lymph to launch an adaptive immune response.