Characterization of Japanese encephalitis virus infection in an immortalized mesencephalic cell line, CSM14.1

Authors

  • Takashi Kimura,

    Corresponding author
    • Division of Molecular Pathobiology, Hokkaido University Research Center for Zoonosis Control, Kita-ku, Sapporo, Japan
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  • Megumi Okumura,

    1. Division of Molecular Pathobiology, Hokkaido University Research Center for Zoonosis Control, Kita-ku, Sapporo, Japan
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  • Eunmi Kim,

    1. Division of Molecular Pathobiology, Hokkaido University Research Center for Zoonosis Control, Kita-ku, Sapporo, Japan
    Current affiliation:
    1. Vaccine I team, Mogam Biotechnology Research Institute, Yongin City, Korea
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  • Michihito Sasaki,

    1. Division of Molecular Pathobiology, Hokkaido University Research Center for Zoonosis Control, Kita-ku, Sapporo, Japan
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  • Yasuko Orba,

    1. Division of Molecular Pathobiology, Hokkaido University Research Center for Zoonosis Control, Kita-ku, Sapporo, Japan
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  • Hirofumi Sawa

    1. Division of Molecular Pathobiology, Hokkaido University Research Center for Zoonosis Control, Kita-ku, Sapporo, Japan
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Correspondence

Takashi Kimura, Division of Molecular Pathobiology, Hokkaido University Research Center for Zoonosis Control, West 10 North 20, Kita-ku, Sapporo 001-0020, Japan.

Tel: +81 11 706 5218; fax: +81 11 706 7370; email: kimura@czc.hokudai.ac.jp

ABSTRACT

Neurons are the major target cell of Japanese encephalitis virus (JEV). Rats intracerebrally inoculated with JEV show an age-dependent pattern of resistance to infection in which resistance is closely associated with neuronal maturation. However, because there is no reliable and convenient cell culture system that mimics the in vivo properties of JEV infection of immature and mature neurons, the mechanisms underlying this association remain poorly understood. The aim of the present study was to examine JEV infection in immortalized CSM14.1 rat neuronal cells, which can be induced to differentiate into neurons by culture under non-permissive conditions. JEV infected undifferentiated CSM14.1 cells more efficiently than differentiated cells, resulting in production of more progeny virus in the former setting than in the latter. An infectious virus recovery assay detected more internalized virions in undifferentiated cells. On the other hand, JEV infection of differentiated cells induced more rapid and stronger expression of interferon-β gene, along with smaller amounts of JEV RNA. Taken together, these results show that the initial phase of viral infection and the later IFN response play roles in the viral susceptibility of undifferentiated and differentiated CSM14.1 cells. Because CSM14.1 cells became more resistant to JEV infection as they mature, this culture system can be used as an in vitro model for studying age-dependent resistance of neurons to JEV infection.

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