title: Regulatory T cells are key cerebroprotective immunomodulators in acute experimental stroke.
abstract: Systemic and local inflammatory processes have a key, mainly detrimental role in the pathophysiology of ischemic stroke. Currently, little is known about endogenous counterregulatory immune mechanisms. We examined the role of the key immunomodulators CD4(+)CD25(+) forkhead box P3 (Foxp3)(+) regulatory T lymphocytes (T(reg) cells), after experimental brain ischemia. Depletion of T(reg) cells profoundly increased delayed brain damage and deteriorated functional outcome. Absence of T(reg) cells augmented postischemic activation of resident and invading inflammatory cells including microglia and T cells, the main sources of deleterious cerebral tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma), respectively. Early antagonization of TNF-alpha and delayed neutralization of IFN-gamma prevented infarct growth in T(reg) cell-depleted mice. Intracerebral interleukin-10 (IL-10) substitution abrogated the cytokine overexpression after T(reg) cell depletion and prevented secondary infarct growth, whereas transfer of IL-10-deficient T(reg) cells in an adoptive transfer model was ineffective. In conclusion, T(reg) cells are major cerebroprotective modulators of postischemic inflammatory brain damage targeting multiple inflammatory pathways. IL-10 signaling is essential for their immunomodulatory effect.
authors.affiliation: Department of Neurology, University Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany.
authors.forename: Arthur
authors.initials: A
authors.lastname: Liesz
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Suri-Payer
authors.forename: Claudia
authors.initials: C
authors.lastname: Veltkamp
authors.forename: Henrike
authors.initials: H
authors.lastname: Doerr
authors.forename: Clemens
authors.initials: C
authors.lastname: Sommer
authors.forename: Serge
authors.initials: S
authors.lastname: Rivest
authors.forename: Thomas
authors.initials: T
authors.lastname: Giese
authors.forename: Roland
authors.initials: R
authors.lastname: Veltkamp
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D019610:Cytoprotection; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D018836:Inflammation Mediators / Q000378:metabolism; D016753:Interleukin-10 / Q000235:genetics / Q000378:metabolism; D008212:Lymphocyte Depletion; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020521:Stroke / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D016207:Cytokines; D018836:Inflammation Mediators; D016753:Interleukin-10