Microglia is one of the four types of glial cell and are the central nervous system equivalent of monocyte-macrophage system 1,2. During health, they are essentially inactive with small cell bodies and numerous processes extending throughout the local parenchyma 1,2. When presented a condition with an inflammatory component, they are able to migrate to the site of activity and become antigen presenting cells, interacting with arriving T-lymphocytes, and able to phagocytose 2.
Embryology
Microglia is of mesenchymal origin, only entering the brain late during fetal development 1.
Histology
Microglial cells are small and difficult to identify on routine light microscopy.
Immunohistochemistry
A number of cell antigens can be targetted to identify these cells, including 1:
- CD68
- ricinus communis agglutinin