title: How do immune cells support and shape the brain in health, disease, and aging?
abstract: For decades, several axioms have prevailed with respect to the relationships between the CNS and circulating immune cells. Specifically, immune cell entry was largely considered to be pathological or to mark the beginning of pathology within the brain. Moreover, local inflammation associated with neurodegenerative diseases such Alzheimer's disease or amyotrophic lateral sclerosis, were considered similar in their etiology to inflammatory diseases, such as remitting relapsing-multiple sclerosis. The ensuing confusion reflected a lack of awareness that the etiology of the disease as well as the origin of the immune cells determines the nature of the inflammatory response, and that inflammation resolution is an active cellular process. The last two decades have seen a revolution in these prevailing dogmas, with a significant contribution made by the authors. Microglia and infiltrating monocyte-derived macrophages are now known to be functionally distinct and of separate origin. Innate and adaptive immune cells are now known to have protective/healing properties in the CNS, as long as their activity is regulated, and their recruitment is well controlled; their role is appreciated in maintenance of brain plasticity in health, aging, and chronic neurodevelopmental and neurodegenerative diseases. Moreover, it is now understood that the barriers of the brain are not uniform in their interactions with the circulating immune cells. The implications of these new findings to the basic understanding of CNS repair processes, brain aging, and a wide spectrum of CNS disorders, including acute injuries, Rett syndrome, Alzheimer's disease, and multiple sclerosis, will be discussed.
authors.affiliation: Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel, Center for Brain Immunology and Glia, Department of Neuroscience, University of Virginia, Charlottesville, Virginia 22908, Neuroscience Laboratory, CHU de Québec Research Center and Department of Molecular Medicine, Faculty of Medicine, Laval University, Quebec City, Quebec G1V 4G2, Canada, and Neuroimmunology Unit, Center for Excellence in Neuromics, CRCHUM, Université de Montréal, Montreal, Quebec H4A 2B4, Canada.
authors.forename: Michal
authors.initials: M
authors.lastname: Schwartz
authors.forename: Jonathan
authors.initials: J
authors.lastname: Kipnis
authors.forename: Serge
authors.initials: S
authors.lastname: Rivest
authors.forename: Alexandre
authors.initials: A
authors.lastname: Prat
mesh_terms: D000375:Aging / Q000276:immunology* / Q000473:pathology; D001921:Brain / Q000276:immunology* / Q000473:pathology; D002493:Central Nervous System Diseases / Q000276:immunology* / Q000473:pathology; D006801:Humans; D008264:Macrophages / Q000276:immunology* / Q000473:pathology; D017628:Microglia / Q000276:immunology* / Q000473:pathology; D019636:Neurodegenerative Diseases / Q000276:immunology / Q000473:pathology