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. 2020 Jun 11;11:1167. doi: 10.3389/fimmu.2020.01167

Figure 2.

Figure 2

Polarization of macrophages by T-helper cells. Tumor associated macrophages (TAMs) are composed of pro-inflammatory M1 macrophages and anti-inflammatory M2 macrophages. IFN-γ, TNF-α, LPS, and GM-CSF induce M1 macrophages polarization. Th2 cytokines induce M2 macrophages polarization. Mo macrophages are circulating monocytes. M1 macrophages display higher expression level of MHC class I than M2 macrophages. M1 macrophages display higher expression level of iNOS than M2 macrophages. M2 macrophages display higher expression level of CD163 than M1 macrophages. Molecules that mediate effects of M1 macrophages or M2 macrophages are shown. SR denotes scavenger receptor. MR denotes mannose receptor. Nitric oxide synthase NOS2 (iNOS) in M1 macrophages converts L-arginine into citrulline and NO. Arginase 1 in M2 macrophages converts L-arginine into polyamine and urea.