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Effects of respiratory syncytial virus infection and major basic protein derived from eosinophils in pulmonary alveolar epithelial cells (A549)

Authors

  • Taisei Ishioka,

    1. Gunma Prefectural Institute of Public Health and Environmental Sciences, 378 Kamiokimachi, Maebashishi, Gunma 3710052, Japan
    2. Department of Virology and Preventive Medicine, Gunma University Graduate School of Medicine, 33922 Showamachi, Maebashishi, Gunma 3718511, Japan
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  • Hirokazu Kimura1,

    Corresponding author
    1. Gunma Prefectural Institute of Public Health and Environmental Sciences, 378 Kamiokimachi, Maebashishi, Gunma 3710052, Japan
    2. Infectious Disease Surveillance Center, National Institute of Infectious Diseases, 471 Gakuen, Musashimurayamashi, Tokyo 2080011, Japan
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  • Hirohito Kita,

    1. Division of Allergic Diseases, Department of Medicine and Department of Immunology, Mayo Clinic, Rochester, MN 55905, U.S.A
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  • Masatsugu Obuchi,

    1. Influenzavirus Research Center, National Institute of Infectious Diseases, 471 Gakuen, Musashimurayamashi, Tokyo 2080011, Japan
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  • Hiroo Hoshino,

    1. Department of Virology and Preventive Medicine, Gunma University Graduate School of Medicine, 33922 Showamachi, Maebashishi, Gunma 3718511, Japan
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  • Masahiro Noda,

    1. Department of Virology III, National Institute of Infectious Diseases, 471 Gakuen, Musashimurayamashi, Tokyo 2080011, Japan
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  • Atsuyoshi Nishina,

    1. *7Yamagata Prefectural Yonezawa Womens Junior College, 6151 Tohrimachi, Yonezawashi, Yamagata 9920025, Japan
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  • Kunihisa Kozawa,

    1. Gunma Prefectural Institute of Public Health and Environmental Sciences, 378 Kamiokimachi, Maebashishi, Gunma 3710052, Japan
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  • Masahiko Kato

    1. †Department of Allergy and Immunology, Gunma Childrens Medical Center, 779 Shimohakoda, Hokkitsumachi, Shibukawashi, Gunma 3778577, Japan
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To whom correspondence should be addressed (email kimhiro@nih.go.jp).

Abstract

RSV (respiratory syncytial virus)-induced pneumonia and bronchiolitis may be associated with hyperresponsive conditions, including asthma. Eosinophilic proteins such as MBP (major basic protein) may also be associated with the pathophysiology of asthma. To elucidate the roles of RSV infection and MBP in the pathogenesis of pneumonia with hyperresponsiveness, we investigated the effects of RSV infection and MBP on A549 (alveolar epithelial) cells. CPE (cytopathic effects) in A549 cells were observed by microscopy. Apoptosis and cell death was evaluated by flow cytometric analysis and modified MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. We also measured 15 types of cytokines and chemokines in A549 cell supernatants. Although RSV alone did not affect the CPE of A549, high concentrations of MBP resulted in cell death within 24 h. Combinations of RSV and MBP synergistically induced cell death. In A549 cells infected with RSV alone, the release of GM-CSF (granulocyte-macrophage colony-stimulating factor) was significantly enhanced compared with control cells (no infection). In the cells treated with MBP alone, the production of IL (interleukin)-2, 4, 5, 7, 10, 12, 13, 17, IFN (interferon)-γ, GM-CSF, G-CSF (granulocyte colony-stimulating factor) and MIP (macrophage inflammatory protein)-1β was significantly increased compared with control cells. Notably, the levels of GM-CSF and IL-17 in RSV/MBP-treated cells were significantly higher than those treated with MBP alone. These results suggest that MBP synergistically enhanced the release of various cytokines/chemokines and the cell death of RSV-infected A549 cells, indicating that MBP may be closely associated with the pathophysiology of allergic reactions in bronchiolitis/pneumonia due to RSV.

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