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. Author manuscript; available in PMC: 2016 Oct 1.
Published in final edited form as: Hepatology. 2015 Jul 1;62(4):1304–1312. doi: 10.1002/hep.27867

Figure 1.

Figure 1

Classically activated M1 and alternatively activated M2 Macrophages. Macrophages originate from myeloid progenitors and circulating monocytes. Macrophages are incredibly plastic in response to various environmental stimuli, and can be in a spectrum of functional states. The two polarization states at the extreme end are the classical activation state (M1) and the alternative activation state (M2). LPS and IFNg generate classically activated M1 macrophages which has proinflammatory activities, express high HLA-DR and IL-12, and stimulate effector T cell function. IL-4, IL-10 and IL-13 generate alternatively activated M2 macrophages which produce low IL-12, high IL-10 and PD-L1 (B7-H1) and has immunosuppressive functions.