title: A pathogenic role for CD8+ T cells in a spontaneous model of demyelinating disease.
abstract: Transgenic (Tg) mice that overexpress the costimulatory ligand B7.2/CD86 on microglia spontaneously develop a T cell-mediated demyelinating disease. Characterization of the inflammatory infiltrates in the nervous tissue revealed a predominance of CD8+ T cells, suggesting a prominent role of this T cell subset in the pathology. In this study, we show that the same neurological disease occurred in Tg mice deficient in the generation of CD4+ T cells, with an earlier time of onset. Analysis of the CD8+ T cell repertoire at early stage of disease revealed the presence of selected clonal expansions in the CNS but not in peripheral lymphoid organs. We further show that Tg animals deficient in IFN-gamma receptor expression were completely resistant to disease development. Microglia activation that is an early event in disease development is IFN-gamma dependent and thus appears as a key element in disease pathogenesis. Collectively, our data indicate that the spontaneous demyelinating disease in this animal model occurs as a consequence of an inflammatory response initiated through the activation of CNS-specific CD8+ T cells by Tg expression of B7.2 within the target organ. Thus, autoreactive CD8+ T cells can contribute directly to the pathogenesis of neuroinflammatory diseases such as multiple sclerosis.
authors.affiliation: Department of Microbiology and Immunology, McGill University, 3775 University Street, Montreal, Quebec, Canada.
authors.forename: Marcel
authors.initials: M
authors.lastname: Brisebois
authors.forename: Simone P
authors.initials: SP
authors.lastname: Zehntner
authors.forename: José
authors.initials: J
authors.lastname: Estrada
authors.forename: Trevor
authors.initials: T
authors.lastname: Owens
authors.forename: Sylvie
authors.initials: S
authors.lastname: Fournier
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000473:pathology*; D002478:Cells, Cultured; D003711:Demyelinating Diseases / Q000235:genetics / Q000276:immunology* / Q000473:pathology*; D004195:Disease Models, Animal; D008231:Lymphopenia / Q000235:genetics / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic