Central Nervous System (CNS)

Central Nervous System (CNS) is composed of the brain and spinal cord
Morais et al. 2021 Nat Rev Microbiol 19(4): 241-255

The idea of CNS immune privilege, which was once believed to separate the mammalian brain from the body's immune system, has changed. Research now shows that immune cells play beneficial roles in both CNS health and disease. Additionally, there are physical pathways that allow communication between the CNS and the immune system. Vascular channels directly connect the skull bone marrow to the brain surface, allowing for the migration of myeloid cells.
Ellwardt et al. 2016 Trends Immunol. 37: 154-165
Herisson et al. 2018 Nat Neurosci 21: 1209-1217

Microglia, the innate myeloid cells of the Central Nervous System (CNS), are the primary immune cells within the CNS parenchyma during homeostasis. However, adaptive immune cells also play crucial roles in maintaining neurogenesis and spatial learning abilities during adulthood.. The human brain is populated by tissue-resident memory T cells.
Ziv et al. 2006 Nat Neurosci 9: 268-275
Smolders et al. 2018 Nat Commun 9: 4593