Macrophage Activation and Polarization

Macrophages populate virtually all tissues in the body and have a myriad of functions in host defense and homeostasis. Macrophages are exquisitely tuned to their microenvironment and alter their phenotype and function in response to both cell–cell interactions and soluble signals such as cytokines. This changeability is often called ‘polarization’ or ‘activation.’ On one end of the spectrum, when a macrophage is stimulated with bacterial …