title: Capture, crawl, cross: the T cell code to breach the blood-brain barriers.
abstract: The central nervous system (CNS) is an immunologically privileged site to which access of circulating immune cells is tightly controlled by the endothelial blood-brain barrier (BBB; see Glossary) localized in CNS microvessels, and the epithelial blood-cerebrospinal fluid barrier (BCSFB) within the choroid plexus. As a result of the specialized structure of the CNS barriers, immune cell entry into the CNS parenchyma involves two differently regulated steps: migration of immune cells across the BBB or BCSFB into the cerebrospinal fluid (CSF)-drained spaces of the CNS, followed by progression across the glia limitans into the CNS parenchyma. With a focus on multiple sclerosis (MS) and its animal models, this review summarizes the distinct molecular mechanisms required for immune cell migration across the different CNS barriers.
authors.affiliation: Theodor Kocher Institute, University of Bern, Freiestrasse 1, CH-3012 Bern, Switzerland. bengel@tki.unibe.ch
authors.forename: Britta
authors.initials: B
authors.lastname: Engelhardt
authors.forename: Richard M
authors.initials: RM
authors.lastname: Ransohoff
mesh_terms: D000818:Animals; D001485:Basement Membrane / Q000166:cytology / Q000276:immunology; D001812:Blood-Brain Barrier / Q000166:cytology / Q000276:immunology*; D002465:Cell Movement; D002490:Central Nervous System / Q000166:cytology / Q000276:immunology; D006801:Humans; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*