title: Host susceptibility to Brucella abortus infection is more pronounced in IFN-γ knockout than IL-12/β2-microglobulin double-deficient mice.
abstract: Brucella abortus is a facultative intracellular bacterial pathogen that causes abortion in domestic animals and undulant fever in humans. IFN-γ, IL-12, and CD8+ T lymphocytes are important components of host immune responses against B. abortus. Herein, IFN-γ and IL-12/β2-microglobulin (β2-m) knockout mice were used to determine whether CD8+ T cells and IL-12-dependent IFN-γ deficiency would be more critical to control B. abortus infection compared to the lack of endogenous IFN-γ. At 1 week after infection, IFN-γ KO and IL-12/β2-m KO mice showed increased numbers of bacterial load in spleens; however, at 3 weeks postinfection (p.i.), only IFN-γ KO succumbed to Brucella. All IFN-γ KO had died at 16 days p.i. whereas death within the IL-12/β2-m KO group was delayed and occurred at 32 days until 47 days postinfection. Susceptibility of IL-12/β2-m KO animals to Brucella was associated to undetectable levels of IFN-γ in mouse splenocytes and inability of these cells to lyse Brucella-infected macrophages. However, the lack of endogenous IFN-γ was found to be more important to control brucellosis than CD8+ T cells and IL-12-dependent IFN-γ deficiencies.
authors.affiliation: Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil.
authors.forename: Ana Paula M S
authors.initials: AP
authors.lastname: Brandão
authors.forename: Fernanda S
authors.initials: FS
authors.lastname: Oliveira
authors.forename: Natalia B
authors.initials: NB
authors.lastname: Carvalho
authors.forename: Leda Q
authors.initials: LQ
authors.lastname: Vieira
authors.forename: Vasco
authors.initials: V
authors.lastname: Azevedo
authors.forename: Gilson C
authors.initials: GC
authors.lastname: Macedo
authors.forename: Sergio C
authors.initials: SC
authors.lastname: Oliveira
mesh_terms: D000818:Animals; D002003:Brucella abortus / Q000276:immunology*; D002006:Brucellosis / Q000235:genetics* / Q000276:immunology*; D020022:Genetic Predisposition to Disease; D006801:Humans; D016898:Interferon-alpha / Q000096:biosynthesis; D007371:Interferon-gamma / Q000235:genetics* / Q000276:immunology; D018664:Interleukin-12 / Q000235:genetics* / Q000276:immunology; D008264:Macrophages / Q000276:immunology / Q000382:microbiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D013154:Spleen / Q000276:immunology / Q000382:microbiology; D001613:beta 2-Microglobulin / Q000235:genetics* / Q000276:immunology
chemical_list: D016898:Interferon-alpha; D001613:beta 2-Microglobulin; D018664:Interleukin-12; D007371:Interferon-gamma