title: Simian retrovirus 4 induces lethal acute thrombocytopenia in Japanese macaques.
abstract: In 2001-2002, six of seven Japanese macaques (Macaca fuscata) died after developing hemorrhagic syndrome at the Kyoto University Primate Research Institute (KUPRI). While the cause of death was unknown at the time, we detected simian retrovirus 4 (SRV-4) in samples obtained from a similar outbreak in 2008-2011, during which 42 of 43 Japanese macaques died after exhibiting hemorrhagic syndrome. In this study, we isolated SRV-4 strain PRI-172 from a Japanese macaque showing severe thrombocytopenia. When inoculated into four Japanese macaques, the isolate induced severe thrombocytopenia in all within 37 days. We then constructed an infectious molecular clone of strain PRI-172, termed pSR415, and inoculated the clone-derived virus into two Japanese macaques. These animals also developed severe thrombocytopenia in just 31 days after inoculation, and the virus was reisolated from blood, bone marrow, and stool. At necropsy, we observed bleeding from the gingivae and subcutaneous bleeding in all animals. SRV-4 infected a variety of tissues, especially in digestive organs, including colon and stomach, as determined by real-time reverse transcription-PCR (RT-PCR) and immunohistochemical staining. Furthermore, we identified the SRV-4 receptor as ASCT2, a neutral amino acid transporter. ASCT2 mRNA was expressed in a variety of tissues, and the distribution of SRV-4 proviruses in infected Japanese macaques correlated well with the expression levels of ASCT2 mRNA. From these results, we conclude that the causative agent of hemorrhagic syndrome in KUPRI Japanese macaques was SRV-4, and its receptor is ASCT2.
  
  
  OBJECTIVE
  During two separate outbreaks at the KUPRI, in 2001-2002 and 2008-2011, 96% of Japanese macaques (JM) that developed an unknown hemorrhagic syndrome died. Here, we isolated SRV-4 from a JM developing thrombocytopenia. The SRV-4 isolate and a molecularly cloned SRV-4 induced severe thrombocytopenia in virus-inoculated JMs within 37 days. At necropsy, we observed bleeding from gingivae and subcutaneous bleeding in all affected JMs and reisolated SRV-4 from blood, bone marrow, and stool. The distribution of SRV-4 proviruses in tissues correlated with the mRNA expression levels of ASCT2, which we identified as the SRV-4 receptor. From these results, we conclude that SRV-4 was the causative agent of hemorrhagic syndrome in JMs in KUPRI.
authors.affiliation: Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, Kyoto, Japan Laboratory of Virolution, Experimental Research Center for Infectious Diseases, Institute for Virus Research, Kyoto University, Kyoto, Japan.
authors.forename: Rokusuke
authors.initials: R
authors.lastname: Yoshikawa
authors.affiliation: Center for Human Evolution Modeling Research, Primate Research Institute, Kyoto University, Inuyama, Aichi, Japan mokamoto@pri.kyoto-u.ac.jp takavet@gmail.com.
authors.forename: Munehiro
authors.initials: M
authors.lastname: Okamoto
authors.affiliation: Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, Kyoto, Japan Laboratory of Virolution, Experimental Research Center for Infectious Diseases, Institute for Virus Research, Kyoto University, Kyoto, Japan.
authors.forename: Shoichi
authors.initials: S
authors.lastname: Sakaguchi
authors.affiliation: Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa, Japan.
authors.forename: So
authors.initials: S
authors.lastname: Nakagawa
authors.affiliation: Laboratory of Primate Model, Experimental Research Center for Infectious Diseases, Institute for Virus Research, Kyoto University, Kyoto, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Miura
authors.affiliation: Molecular Biology Section, Department of Cellular and Molecular Biology, Primate Research Institute, Kyoto University, Inuyama, Aichi, Japan.
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Hirai
authors.affiliation: Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, Kyoto, Japan Laboratory of Virolution, Experimental Research Center for Infectious Diseases, Institute for Virus Research, Kyoto University, Kyoto, Japan mokamoto@pri.kyoto-u.ac.jp takavet@gmail.com.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Miyazawa
mesh_terms: D000818:Animals; D030121:Betaretrovirus / Q000472:pathogenicity* / Q000502:physiology*; D001769:Blood / Q000821:virology; D001853:Bone Marrow / Q000821:virology; D005243:Feces / Q000821:virology; D041981:Gastrointestinal Tract / Q000473:pathology / Q000821:virology; D006470:Hemorrhage / Q000209:etiology*; D007150:Immunohistochemistry; D008251:Macaca; D018419:Primate Diseases / Q000473:pathology* / Q000821:virology*; D060888:Real-Time Polymerase Chain Reaction; D012192:Retroviridae Infections / Q000150:complications / Q000473:pathology / Q000662:veterinary*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013921:Thrombocytopenia / Q000150:complications / Q000209:etiology / Q000662:veterinary*