A macrophage is an immune system cell .
Structure of macrophages
A macrophage is a cell originating from the blood and produced from the transformation of a monocyte.
It is found in tissues which may suffer infections or accumulation of waste which needs to be removed (liver, lungs, lymph nodes, spleen, etc.)
Function of macrophages
Macrophages have three main functions :
- firstly, phagocytosis (ingestion of bacteria, yeasts, cell debris..). The intracellular vesicle formed is called the phagosome, which is carried to the lysosome to be fully degraded;
- secondly, secretory activity (cytokines..) ;
- and thirdly, cell cooperation (this is the antigen presenting cell which communicates with lymphocytes).
They are therefore cells involved in innate immunity as they phagocytose non-specific materials. They are attracted to the site of inflammation by chemotaxis.
Macrophages can phagocytose foreign bodies. © Obli, Wikimedia, CC by-sa 2.0