Review Article

Macrophages, Inflammation, and Tumor Suppressors: ARF, a New Player in the Game

Figure 1

Simplified scheme for M1 and M2 activation of macrophages. M1 macrophages are induced by LPS or IFN-γ secreting high levels of classical proinflammatory cytokines such as TNF-α, IL-1, IL-6, IL-12, or IL-23, chemokines (e.g., Cxcl9, Cxcl10, and Cxcl5) and increasing their concentrations of NO. In addition, they express high levels of MHC I. IL-4/IL-13 stimulation induces M2 macrophages that downregulate IL-12 and IL-23 expression, release Ccl17, Ccl22 and Ccl24 chemokines and proangiogenic factors, and show increased expression of IL-10. Additionally, they are characterized by expression of MR, Fizz-1, and Ym1.
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