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Lon Mutant of Brucella abortus Induces Tumor Necrosis Factor-Alpha in Murine J774.A1 Macrophage

OBJECTIVES: The objective of this study was to isolate a Brucella lon mutant and to analyze the cytokine response of B. lon mutant during macrophage infection. METHODS: A wild-type Brucella abortus strain was mutagenized by Tn5 transposition. From the mouse macrophage J774.A1 cells, total RNA was is...

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Detalles Bibliográficos
Autores principales: Park, Sungdo, Choi, Young-Sill, Park, Sang-Hee, Kim, Young-Rok, Chu, Hyuk, Hwang, Kyu-Jam, Park, Mi-Yeoun
Formato: Online Artículo Texto
Lenguaje:English
Publicado: 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3922098/
https://www.ncbi.nlm.nih.gov/pubmed/24524018
http://dx.doi.org/10.1016/j.phrp.2013.10.002
Descripción
Sumario:OBJECTIVES: The objective of this study was to isolate a Brucella lon mutant and to analyze the cytokine response of B. lon mutant during macrophage infection. METHODS: A wild-type Brucella abortus strain was mutagenized by Tn5 transposition. From the mouse macrophage J774.A1 cells, total RNA was isolated at 0 hours, 6 hours, 12 hours, and 24 hours after infection with Brucella. Using mouse cytokine microarrays, we measured transcriptional levels of the cytokine response, and validated our results with a reverse transcriptase-polymerase chain reaction (RT-PCR) assay to confirm the induction of cytokine messenger RNA (mRNA). RESULTS: In host J774.A1 macrophages, mRNA levels of T helper 1 (Th1)-type cytokines, including tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), interleukin-2 (IL-2), and IL-3, were significantly higher in the lon mutant compared to wild-type Brucella and the negative control. TNF-α levels in cell culture media were induced as high as 2 μg/mL after infection with the lon mutant, a greater than sixfold change. CONCLUSION: In order to understand the role of the lon protein in virulence, we identified and characterized a novel B. lon mutant. We compared the immune response it generates to the wild-type Brucella response in a mouse macrophage cell line. We demonstrated that the B. lon mutants induce TNF-α expression from the host J774.A1 macrophage.