Nomenclature of monocytes and DCs in blood. The 6 types of cells are shown with different symbols, which represent the crucial markers of the respective cells. Blue hook indicates CD14; red square flag, CD16; green flag, CD303; blue flag, CD1c; red diamond flag, CD141. A higher number of a given symbol indicates a higher density of a given receptor. The arrows in the upper portion represent the developmental relationship. This does not necessarily indicate that development is actually occurring in the blood compartment. The location of the nonclassical monocytes closer to the vessel wall is to indicate that these cells preferentially localize to the marginal pool, a concept supported by the intravital microscopic data for the mouse homologue. The 2 types of myeloid DCs are depicted closer to each other because both are closer related to each other compared with the plasmacytoid DCs.