The role of immune cells at the dura mater for active CNS immunosurveillance

Abstract

Despite considerable efforts to explain the morphological and immunological heterogeneities of the central nervous system (CNS) border tissues, their functional differences and relative contribution to immune surveillance are poorly understood. Here, I compare the distinct features of the dura mater, subdural meninges, brain cortex, and choroid plexus. Unlike other CNS border tissues, the dura mater lacks a tight blood or cerebrospinal fluid barrier but is equipped with a sinus-associated immune barrier. In neonates, the immature sinus-associated immune barrier allows virus invasion into the CNS through the peri-sinus region of the dura, which can lead to fatal viral propagation. In adults, a dural immune barrier composed of border-associated mononuclear phagocytes is a key player in defending the CNS against systemic virus invasion. My findings clarify how systemic pathogens enter the CNS through the border tissues and how the border-associated innate immune system guards against pathogen entry into the CNS.