Fig. 1.

Types of multinucleated giant cells derived from monocyte/macrophage precursors. Pathways leading to formation of the primary types of munlinucleated macrophages are shown. Major cytokines known to be involved in the differentiation/fusion of monocyte/macrophage precursors are indicated. Proposed pathways that are not well defined are indicated by dashed lines. M-CSF = Macrophage colony-stimulating factor; GM-CSF = granulocyte-macrophage colony-stimulating factor; RANKL = receptor activator for nuclear factor-κ B ligand; IL-3 = interleukin 3; IL-4 = interleukin 4; IL-6 = interleukin 6; IL-13 = interleukin 13; IFN-γ = interferon-γ. See text for further details.