[HTML][HTML] The M1 and M2 paradigm of macrophage activation: time for reassessment

FO Martinez, S Gordon - F1000prime reports, 2014 - ncbi.nlm.nih.gov
FO Martinez, S Gordon
F1000prime reports, 2014ncbi.nlm.nih.gov
Macrophages are endowed with a variety of receptors for lineage-determining growth
factors, T helper (Th) cell cytokines, and B cell, host, and microbial products. In tissues,
macrophages mature and are activated in a dynamic response to combinations of these
stimuli to acquire specialized functional phenotypes. As for the lymphocyte system, a
dichotomy has been proposed for macrophage activation: classic vs. alternative, also M1
and M2, respectively. In view of recent research about macrophage functions and the …
Abstract
Macrophages are endowed with a variety of receptors for lineage-determining growth factors, T helper (Th) cell cytokines, and B cell, host, and microbial products. In tissues, macrophages mature and are activated in a dynamic response to combinations of these stimuli to acquire specialized functional phenotypes. As for the lymphocyte system, a dichotomy has been proposed for macrophage activation: classic vs. alternative, also M1 and M2, respectively. In view of recent research about macrophage functions and the increasing number of immune-relevant ligands, a revision of the model is needed. Here, we assess how cytokines and pathogen signals influence their functional phenotypes and the evidence for M1 and M2 functions and revisit a paradigm initially based on the role of a restricted set of selected ligands in the immune response.
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