Macrophages are very plastic cells and therefore the M1/M2 paradigm is used to help understand in vitro macrophage activation states.  Beware in vivo these phenotypic changes are more complex.  It is best to view these cells as being on continuum rather than static.  To get started Mantovani is a wonderful researcher on this topic.  Read these articles to get started.  "Macrophage plasticity and polarization: in vivo veritas" by Sica 2012.  https://www.ncbi.nlm.nih.gov/pubmed/22378047

and "Macrophage activation and polarization: nomenclature and experimental guidelines" by Murray et al 2015  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4123412/

Hi,

When observed the table of your article, we see that M2 macrophages release increased levels of proinflammatory cytokines than M1 macrophages!!! While, M1 macrophages are considered as proinflammatory cells, and can eradicate microbes and malignant cells; conversly, M2 macrophages are anti-inflammatory cells, and are involved in infectious diseases and cancer. They usualy release anti-inflammatory/regulatory cytokines.

Hi,

and what about structural difference? Are both types of macrophages the same morphologically?

Thank you.