CCL2 and infection: Pathogen-induced infections generally cause rapid and massive production of various cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1, IL-6, IL-12, interferon (IFN)-α, IFN-β, IFN-γ, monocyte chemoattractant protein-1 (MCP-1) and IL-8 [15,16], which can promote the development of harmful inflammation.