Immunobiology of the blood-brain barrier

The brain microvessel endothelial cells (BMVEC) that form the blood-brain b arrier are uniquely positioned to influence immune responses within the cen tral nervous system. As the biological interface separating the blood from the brain extracellular fluid, BMVEC regulate the entry of leukocytes into the brain. in addition, through the release of various soluble factors that affect immune responses, BMVEC may modulate immune responses in the brain. This review addresses the interplay between the immune system and the bloo d-brain barrier as it relates to the regulation of CNS defense and immunity .