Fig. 2
From: Tumor-associated macrophages: an accomplice in solid tumor progression
Macrophage differentiation and their characteristics. M1 macrophages are activated by IFN-γ, LPS or TLR ligands, expressing MHC-II, CD68, CD80, CD86, and secreting IL-6, IL-12, IL-23, and exerting pro-inflammatory, cytotoxic and tumoricidal roles. On the contrary, M2 macrophages and TAMs exert immunosuppressive and pro-tumorigenic roles. In general, TAMs are thought to more closely resembleM2 macrophages. Both TAMs and M2 macrophages are activated by helper T cell 2 cytokines IL-4 and IL-13, expressing CD163, CD206, Arg1, and secreting IL-10 and TGFβ. However, TAMs show some characteristics different from M2 macrophages. For example, TAMs express Fc of IgG, C-type lectin, HSP, and secret CCL2 and CCL5.M2 macrophages express high levels of MGL1 and MGL2, members of the macrophage galactose type C-lectin family