title: Effect of brazilian propolis on exacerbation of respiratory syncytial virus infection in mice exposed to tetrabromobisphenol a, a brominated flame retardant.
abstract: Tetrabromobisphenol A (TBBPA), a brominated flame retardant, has been found to exacerbate pneumonia in respiratory syncytial virus- (RSV-) infected mice. We examined the effect of Brazilian propolis (AF-08) on the exacerbation of RSV infection by TBBPA exposure in mice. Mice were fed a powdered diet mixed with 1% TBBPA alone, 0.02% AF-08 alone, or 1% TBBPA and 0.02% AF-08 for four weeks and then intranasally infected with RSV. TBBPA exposure increased the pulmonary virus titer and level of IFN- γ , a representative marker of pneumonia due to RSV infection, in the lungs of infected mice without toxicity. AF-08 was significantly effective in reducing the virus titers and IFN- γ level increased by TBBPA exposure. Also, AF-08 significantly reduced proinflammatory cytokine (TNF- α and IL-6) levels in the lungs of RSV-infected mice with TBBPA exposure, but Th2 cytokine (IL-4 and IL-10) levels were not evidently increased. Neither TBBPA exposure nor AF-08 treatment affected the anti-RSV antibody production in RSV-infected mice. In flow cytometry analysis, AF-08 seemed to be effective in reducing the ratio of pulmonary CD8a(+) cells in RSV-infected mice with TBBPA exposure. TBBPA and AF-08 did not exhibit anti-RSV activity in vitro. Thus, AF-08 probably ameliorated pneumonia exacerbated by TBBPA exposure in RSV-infected mice by limiting excess cellular immune responses.
authors.affiliation: Department of Biochemistry, Graduate School of Clinical Pharmacy, Kyushu University of Health and Welfare, 1714-1 Yoshino, Miyazaki, Nobeoka 882-8508, Japan.
authors.forename: Tomomi
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authors.lastname: Takeshita
authors.forename: Wataru
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authors.lastname: Watanabe
authors.forename: Satomi
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authors.lastname: Toyama
authors.forename: Yuya
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authors.lastname: Hayashi
authors.forename: Shiori
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authors.lastname: Sakamoto
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authors.forename: Hiroki
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authors.forename: Shiro
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authors.lastname: Takeda
authors.forename: Muneaki
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authors.lastname: Hidaka
authors.forename: Shigetoshi
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authors.lastname: Tsutsumi
authors.forename: Ken
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authors.lastname: Yasukawa
authors.forename: Yong Kun
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authors.lastname: Park
authors.forename: Masahiko
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authors.lastname: Kurokawa