Which glial cells are primarily involved in the immune response of the central nervous system?

Microglia are the primary immune cells of the central nervous system (CNS). They play a crucial role in monitoring the health of the CNS and responding to injury or disease. These specialized glial cells are capable of phagocytosis, meaning they can engulf and digest cellular debris, pathogens, and dead neurons, thereby helping to maintain homeostasis within the CNS. Microglia constantly survey the tissue environment, and upon detecting insults, they can become activated, proliferate, and migrate to the site of injury to carry out their immune functions. This unique capability distinguishes microglia as the first line of defense in the CNS's immune response, differentiating them from other types of glial cells that have different roles.

Astrocytes, while important for supporting neurons and maintaining the blood-brain barrier, do not primarily function in the immune response. Oligodendrocytes are responsible for myelinating axons in the CNS, and Schwann cells, found in the peripheral nervous system, are primarily involved in myelination there as well. Thus, the specialized functions of these other glial cells do not include the direct immune response role that microglia fulfill.