NEUROLOGY 2010;74:S9-S16
© 2010 American Academy of Neurology
The interplay between the immune and central nervous systems in neuronal injury
V. Wee Yong, PhD and
Steven Marks
From the Departments of Clinical Neurosciences and Oncology and the MS Program (V.W.Y.), Hotchkiss Brain Institute, University of Calgary Faculty of Medicine, Alberta, Canada; and Expert Medical Education, Washington, DC (S.M.).
Address correspondence and reprint requests to Dr. V. Wee Yong, Departments of Clinical Neurosciences and Oncology, University of Calgary, 3330 Hospital Drive, Calgary, Alberta, Canada T2N 4N1 vyong{at}ucalgary.ca
Once perceived as a region of limited immune activity, the CNS is now known to be an important site of immune interactions. Activated T cells can infiltrate the blood-brain barrier where they accumulate and proliferate in response to antigen restimulation. These leukocytes express proinflammatory cytokines that help in activating microglia and other immune cells. A profound inflammatory response ensues, which can lead to axonal injury and demyelination. In contrast, other T cells can be neuroprotective. CD4+ Th2 cells secrete anti-inflammatory cytokines and can elicit the production of bioactive neurotrophins from CNS glia. In addition, neurons themselves can contribute to immune system regulation by being targets of neurotoxic T cells or by altering T-cell activity, including the generation of regulatory T cells. The interplay between components of the immune system and CNS contributes both to healthy brain function and to the pathogenesis of neurodegenerative diseases such as multiple sclerosis.
Abbreviations: ARD = autoimmune rheumatic diseases; BBB = blood-brain barrier; BDNF = brain-derived neurotrophic factor; EAE = experimental autoimmune encephalitis; ECM = extracellular matrix; FGF = fibroblast growth factor; HPA = hypothalamic-pituitary-adrenal; IGF = insulin-like growth factor; IL = interleukin; IVIG = IV immunoglobulin; SCI = spinal cord injury; MHC = major histocompatibility complex; MMP = matrix metalloproteinase; M/M = monocytes/macrophages; NT-3 = neurotrophin-3; NO = nitric oxide; OPC = oligodendrocyte precursor cell; PDGF = platelet-derived growth factor; TLR = toll-like receptor; TNF = tumor necrosis factor.
This supplement was supported by an educational grant from Teva Neuroscience. Expert Medical Education contributed to the editorial refinement of this article and to the production of this supplement. Authors may have accepted honoraria for their supplement contributions.
Disclosure: Author disclosures are provided at the end of the article.
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