title: Pathogenicity of Toxoplasma gondii through B-2 cell-mediated downregulation of host defense responses.
abstract: IFN-gamma is the primary mediator of anti-parasite effector mechanisms against Toxoplasma gondii. After intraperitoneal infection with the Fukaya strain of T. gondii, unirradiated IFN-gamma knock-out (GKO) mice transferred with wild type (WT) CD8+ effector T cells from infected mice failed to induce the production of IFN-gamma and died, whereas irradiated (IR) GKO mice transferred with WT CD8+ T cells induced IFN-y production and survived more than 6 months. IR GKO mice transferred with WT CD8+ T cells together with GKO B-2 cells died 8 days after infection, whereas those transferred with WT CD8+ T cells together with B-la or T cells survived. B-2 cells of infected GKO mice activated CD11b+ cells for IL-4 production, and down-regulated NO release, STAT1 phosphorylation, and interferon regulatory factor-1 expression in the peritoneal exudates cells of IR GKO mice transferred with WT CD8+ T cells together with GKO B-2 cells after infection. Thus, B-2 cells in T. gondii-infected mice act as suppressor cells in the host defense of infected mice.
authors.affiliation: Department of Infection and Host Defense, Graduate School of Medicine, Chiba University, Chiba, Chiba 260-8670, Japan.
authors.forename: Hye-Seong
authors.initials: HS
authors.lastname: Mun
authors.forename: Fumie
authors.initials: F
authors.lastname: Aosai
authors.forename: Mei
authors.initials: M
authors.lastname: Chen
authors.forename: Lian-Xun
authors.initials: LX
authors.lastname: Piao
authors.forename: Kazumi
authors.initials: K
authors.lastname: Norose
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Iwakura
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yano
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D015536:Down-Regulation; D007109:Immunity / Q000528:radiation effects; D007371:Interferon-gamma / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D009569:Nitric Oxide / Q000378:metabolism; D050794:STAT1 Transcription Factor; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000637:transplantation; D014122:Toxoplasma / Q000472:pathogenicity*; D014124:Toxoplasmosis, Animal / Q000276:immunology* / Q000503:physiopathology*; D015534:Trans-Activators / Q000378:metabolism; D014965:X-Rays
chemical_list: D016207:Cytokines; D004268:DNA-Binding Proteins; D050794:STAT1 Transcription Factor; C494080:Stat1 protein, mouse; D015534:Trans-Activators; D009569:Nitric Oxide; D007371:Interferon-gamma