Microglia

Microglia is one of the four types of glial cell and are the central nervous system equivalent of monocyte-macrophage system . During health, they are essentially inactive with small cell bodies and numerous processes extending throughout the local parenchyma . 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 .

Embryology

Microglia is of mesenchymal origin, only entering the brain late during fetal development .

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 :

• CD68
• ricinus communis agglutinin