Inflammatory processes in the aging mouse brain: participation of dendritic cells and T-cells.
Increased inflammatory activity accompanies normal brain aging. Whereas local glial cell activation, upregulation of cytokines and transcriptional alterations of inflammatory factors are well-documented components of this complex process, it is unclear whether blood-derived leukocytes also contribute to the age-related changes. The present study of normal mouse brain applied single and double immunohistochemistry to reveal for the first time that dendritic cells (DCs) and T-cells are important components of the general increased inflammatory state, which was documented by upregulation of reactive astrocytes and microglia. B-cells and mast cells do not contribute to this inflammatory response. Dendritic cells and T-cells appeared at about 12 months of age and their number increased further during aging. In 24-month-old animals a dense network of DCs interspersed with T-cells pervaded brain areas where substantial histopathological changes and a volumetric decrease have been reported. All CD11c(+)-DCs displayed the typical dendritic shape and expressed the myeloid specific integrin CD11b. Some of the DCs were also CD205- or MIDC8-immunoreactive and expressed the cathepsins S and X. The emergence and prolonged presence of leukocytes might indicate a crucial role of these cells in local, age-related immune responses in the brain.
Stichel
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CC
Biofrontera Bioscience GmbH, D-51377 Leverkusen, Germany. c.stichel-gunkel@biofrontera.com
Luebbert
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H
D000375:Aging / Q000276:immunology* / Q000473:pathology; D000818:Animals; D015703:Antigens, CD / Q000276:immunology; D001253:Astrocytes / Q000276:immunology / Q000473:pathology; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000276:immunology* / Q000473:pathology; D018845:CD11 Antigens / Q000276:immunology; D002403:Cathepsins / Q000276:immunology; D049109:Cell Proliferation; D002634:Chemotaxis, Leukocyte / Q000276:immunology*; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology*; D004660:Encephalitis / Q000276:immunology* / Q000473:pathology; D005260:Female; D007150:Immunohistochemistry; D037181:Lectins, C-Type / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000276:immunology / Q000473:pathology; D015778:Minor Histocompatibility Antigens; D011956:Receptors, Cell Surface / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
D015703:Antigens, CD; D015415:Biomarkers; D018845:CD11 Antigens; C093569:DEC-205 receptor; D037181:Lectins, C-Type; D015778:Minor Histocompatibility Antigens; D011956:Receptors, Cell Surface; D002403:Cathepsins