Monocyte Activation in Immunopathology: Cellular Test for Development of Diagnostics and Therapy

Figure 1

Simplified scheme of macrophage polarization. Activation of monocytes is followed by the polarization of macrophages to acquire proinflammatory phenotype (M1) or anti-inflammatory phenotypes (M2a–M2c) depending on the activation stimuli. Each phenotype is characterized by the secretion of a distinct pattern of pro- or anti-inflammatory cytokines and other molecules. For instance, M1 macrophages release TNFα, IL-1β, IL-6, IL-12, and other proinflammatory cytokines, whereas M2a macrophages produce CCL18, TGF-β, collagen, and other extracellular matrix components. LPS: bacterial lipopolysaccharides; IC: immune complexes; IFN-γ: interferon gamma; IL: interleukin; TNFα: tumor necrosis factor-alpha; TGF-β: transforming growth factor beta; CCL18: CC chemokine ligand 18.