Double Roles of Macrophages in Human Neuroimmune Diseases and Their Animal Models

Figure 2

Macrophage polarization into proinflammatory and anti-inflammatory macrophages. Macrophages polarize and acquire different functional properties in response to numerous factors from the microenvironment. Macrophages activated by IFN-γ, LPS, or TNF-α can develop proinflammatory macrophages, with strong microbicidal and tumoricidal properties. In contrast, anti-inflammatory macrophages contribute to Th2 response, immunoregulation, and tissue remodeling. Anti-inflammatory macrophages have different subsets. M(IL-4) macrophages (induced by exposure to IL-4) secret TNF-α, IL-1, and IL-6 and induce Th2 cell response and allergy. M(IC) macrophages (induced by IC) secret IL-10 and exert immunoregulatory function. M(IL-10) macrophages (induced by IL-10) secret IL-10 and TGF-β, suppress immune responses, and promote tissue remodeling. CCL, CC-chemokine ligand; CXCL, CXC-chemokine ligand; IC, immune complexes; IFN-γ, interferon γ; LPS, lipopolysaccharide; MHC-II, major histocompatibility complex-II; MR, mannose receptor; NO, nitric oxide; ROI, reactive oxygen intermediates; SLAM, signaling lymphocytic activation molecule; SR, scavenger receptor; TGF-β, transforming growth factor-β; TLR, toll-like receptor; TNF-α, tumor necrosis receptor-α.