Interleukin-8 (IL-8) is a chemokine produced by macrophages and other cell types such as epithelial cells. It is also synthesized by endothelial cells, which store IL-8 in their storage vesicles, the Weibel-Palade bodies. When first encountering an antigen, the primary cells to encounter it are the macrophages who phagocytose the particle. Upon processing, they release chemokines to signal other immune cells to come in to the site of inflammation. IL-8 is one such chemokine. It serves as a chemical signal that attracts neutrophils at the site of inflammation, and therefore is also known as Neutrophil Chemotactic Factor Synonyms: IL-8, CXCL8, Monocyte-derived neutrophil chemotactic factor, MDNCF, T-cell chemotactic factor, Neutrophil-activating protein 1, NAP-1, Protein 3-10C, Granulocyte chemotactic protein 1, GCP-1, Monocyte-derived neutrophil-activating peptide, MONAP, Emoctakin, K60, NAF, LECT, LUCT, 3-10C, LYNAP, SCYB8, TSG-1, AMCF-I, b-ENAP, Alveolar macrophage chemotactic factor I.