Table 3.

– Function of brain resident immune cells.

Brain resident immune cells
Cell type	Physiological cell function
Microglia	Glial cell that inspect the local microenvironment and respond to injuries by releasing pro-inflammatory molecules; phagocytosis clearance of apoptotic cells [63]
Astrocytes	Help form the physical structure of the brain and play a number of active roles, including the secretion or absorption of neural transmitters and maintenance of the BBB [63]
Pericytes	Regulate the BBB permeability; the clearance and phagocytosis cellular debris; and has a neurogenic potential being able to differentiate into neurons [63]
Perivascular macrophages	Phagocytosis of cellular and pathogenic debris; maintains brain homeostasis; maintains tight junctions; initiation of the CNS acute phase response via the production of prostaglandins [63]

BBB: blood brain barrier; CNS: central nervous system.