Updated on 2023/09/19



Associate Professor


Associate Professor



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From School 【 display / non-display

  • Rakuno Gakuen University   School of Veterinary Medicine   Department of Veterinary Medicine   Graduated

    2001.04 - 2007.03

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From Graduate School 【 display / non-display

  • Kyoto University   Graduate School of medicine   Medicine   Doctor Course   Completed

    2007.04 - 2011.03

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Degree 【 display / non-display

  • 博士(医学) ( 2011.03   京都大学 )

Employment Record in Research 【 display / non-display

  • Tokyo University of Agriculture   Faculty of Agriculture   Department of Animal Science   Assistant Professor

    2014.04 - 2018.03

  • Tokyo University of Agriculture   Faculty of Agriculture   Department of Animal Science   Assistant Professor

    2018.04 - 2020.03

  • Tokyo University of Agriculture   Faculty of Agriculture   Department of Animal Science   Associate Professor


External Career 【 display / non-display

  • Institute for Virus Research Kyoto University   Laboratory of Viral Pathogenesis   post doctoral fellow

    2012.07 - 2014.03

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  • National Institute of Animal Health, National Agriculture and Food Research Organization (NARO)   Viral Disease and Epidemiology Research Division ,Zoonotic Diseases Collaboration Center (ZDCC), Bangkok, Thailand   post doctoral fellow

    2011.04 - 2012.03

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Research Areas 【 display / non-display

  • Life Science / Virology

Papers 【 display / non-display

  • Genetic Diversity of BoLA-DRB3 in Japanese Brown Cattle

    NISHIKAKU Kohei, INENAGA Toshiaki, NISHI Akihito, YONEZAWA Takahiro, NOGUCHI Tatsuo, TORII Yasushi, IMAKAWA Kazuhiko, KOBAYASHI Tomoko

    Journal of Veterinary Epidemiology   26 ( 2 )   108 - 115   2022.12

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    Authorship:Corresponding author   Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:The Japan Society of Veterinary Epidemiology  

    <p>Enzootic bovine leukosis is the most common neoplastic disease in cattle caused by the bovine leukemia virus (BLV). Previous studies have shown that allele type in the <i>DRB3</i> region of the bovine major histocompatibility complex (bovine leukocyte antigen: <i>BoLA</i> in cattle) is associated with resistance or susceptibility to infectious diseases. The Japanese brown (JBR) cattle have a genetic background of small population size, and thus, may exhibit different susceptibility to diseases compared with other cattle breeds. In the present study, we analyzed the diversity of the <i>BoLA-DRB3</i> gene and attempted to clarify the genetic composition of the Kumamoto and Kochi strains belonging to the JBR.</p><p>Allele typing of the <i>BoLA-DRB3</i> gene of 184 JBR detected 16 and 13 alleles in the Kumamoto and Kochi strains, respectively. The analysis of the observed (<i>H</i>o) and expected (<i>H</i>e) heterozygosity of the JBR based on allele frequencies, as well as <i>F</i>is (using <i>H</i>o and <i>H</i>e), which indicates the inbreeding coefficient within a population, showed each population to have different <i>BoLA-DRB3</i> gene diversities. Consequently, the degree of genetic difference among the populations (<i>F</i>st) was analyzed based on the allele frequencies of the <i>BoLA-DRB3</i> gene. The results showed the JBR populations to be genetically closer to the native Philippine and Myanmar cattle populations than the Japanese black, Japanese Shorthorn, Holstein or Jersey population. Furthermore, the proportions of cattle with at least on allele, which was reported to be associated with low proviral load (PVL) on infection of BLV, were 15.7% (20/127) and 63.1% (37/57) in Kumamoto and Kochi strain, respectively, and showed a significant difference. In the future, the direct evaluation of the <i>BoLA-DRB3</i> gene allele types and PVL in BLV-infected individual cattle is warranted. In addition, the PVL of BLV-infected JBR of the Kumamoto strain is known to be lower than that of other breeds in Japan. Therefore, it is necessary to investigate the possibility of a different mechanism on PVL regulation from allele types.</p><p>The results of <i>BoLA-DRB3</i> gene diversity and allele frequency analysis indicate that the JBR has a different genetic background from the Japanese black and the Shorthorn populations and possesses low PVL-associated alleles. Further studies are needed to analyze the relationship between PVL and <i>BoLA-DRB3</i> gene in JBR to clarify the susceptibility of JBR to BLV.</p>

    DOI: 10.2743/jve.26.108

  • Clone Dynamics and Its Application for the Diagnosis of Enzootic Bovine Leukosis. International journal

    Hossain MB, Kobayashi T*, Makimoto S, Matsuo M, Nishikaku K, Tan BJY, Rahman A, Rajib SA, Sugata K, Ohnuki N, Saito M, Inenaga T, Imakawa K, Satou Y*

    19 ( e0154222 )   2022.12

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    Authorship:Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: https://doi.org/10.1128/jvi.01542-22 *Correspondence

  • Phylogenomics and Spatiotemporal Dynamics of Bovine Leukemia Virus (BLV) Focusing on Asian Native Cattle: Insights Into the Early Origin and Global Dissemination. Reviewed International coauthorship International journal

    Nishikaku K, Yonezawa T, Nishibori M, Harada M, Kawaguchi F, Sasazaki S, Torii Y, Imakawa K, Kawai K, Liu J, Mannen H and Kobayashi T

    Frontiers in Microbiology   13   917324   2022.06

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    Authorship:Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

  • Molecular analysis of bovine leukemia virus in early epidemic phase in Japan using archived formalin fixed paraffin embedded histopathological specimens Reviewed

    NISHIKAKU Kohei, NOGUCHI Tatsuo, MURAKAMI Satoshi, TORII Yasushi, KOBAYASHI Tomoko

    Journal of Veterinary Medical Science   84 ( 3 )   350 - 357   2022

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    Authorship:Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:JAPANESE SOCIETY OF VETERINARY SCIENCE  

    <p>Bovine leukemia virus (BLV) is an important pathogen associated with enzootic bovine leukosis. In this study, we performed PCR and sequencing analysis to characterize BLVgp51 sequences from formalin-fixed paraffin-embedded (FFPE) specimens made from 1974 to 2000 and successfully obtained BLV proviral genome sequences from 94% of the analyzed samples. Furthermore, from these samples, we reconstructed eight full-length and nearly full-length BLVgp51 sequences. These sequences were classified as BLV genotype 1, implying that genotype1 has already been circulating in Japan since the 1970s. In our results, the proviral DNA was detected in the 1970s, 1980s, and 1990s in the same manner, indicating that the detection of BLV proviral genome depends on storage conditions rather than storage period. The sequences obtained in this study provide direct insights into BLV sequences before 2000, which serves as a good calibrator for inferring ancient BLV diversity.</p>

    DOI: 10.1292/jvms.21-0570


    CiNii Articles

  • A target enrichment high through-put sequencing system for characterization of BLV whole genome sequence, integration sites, clonality and host SNP Reviewed

    Ohnuki N†, Kobayashi T†, Matsuo M, Nishikaku K, Kusamam K, Torii Y, Inagaki Y, Hori M, Imakawa K and Satou Y

    Scientific Reports   11   4521   2021

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    Authorship:Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

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Books and Other Publications 【 display / non-display

  • 動物の衛生 第2版

    末吉益雄、伊藤秀一、髙井伸二、佐々木羊介、伊藤琢也、井上 亮、竹原一明、髙橋俊彦、山口剛士、上塚浩司、森友靖生、上村涼子、山中典子、小林朋子、丹羽秀和、鳥居恭司、大久保倫子、羽賀清典( Role: Joint author)

    文永堂出版  2020.03 

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    Language:Japanese   Book type:Scholarly book

Honours, Awards and Prizes 【 display / non-display

  • 優秀口頭発表賞

    2017.03   日本獣医疫学会   ウイルス遺伝子配列からみた牛白血病ウイルスの流行動態の解析

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    Award type:International academic award (Japan or overseas)  Country:Japan

Scientific Research Funds Acquisition Results 【 display / non-display

  • 牛伝染性リンパ腫ウイルスの感染評価系の構築とエンベロープ多様性の解析

    2021 - 2023

    科学研究費補助金  基盤研究(C)


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    Authorship:Principal investigator 

Other External Funds 【 display / non-display

  • 牛白血病ウイルス感染牛はなぜ増え続けるのか

    2016.04 - 2017.03


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    Authorship:Principal investigator  Grant type:Competitive

  • Functional analysis of bovine leukemia virus microRNA

    2014.10 - 2016.09

    Private Foundation 

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    Authorship:Principal investigator  Grant type:Competitive

Presentations 【 display / non-display

  • BLV感染細胞のクローナリティを指標とした牛伝染性リンパ腫発症診断方法の検討

    牧元櫻子、Md Belal Hossain、松尾美沙希、大貫永輝、Akhinur Rahman、佐藤賢文、小林朋子

    第59回獣医疫学会(オンライン開催)  2022.03  日本獣医疫学会

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    Event date: 2022.03

    Language:Japanese   Presentation type:Oral presentation (general)  

  • 抗体調査結果を用いた牛伝染性リンパ腫ウイルスの基本再生産数の推定


    第57回獣医疫学会発表要旨集(オンライン開催)  2021.03  日本獣医疫学会

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    Event date: 2021.03

    Language:Japanese   Presentation type:Oral presentation (general)  

  • 日本産コウモリのゲノムに存在する古代デルタレトロウイルス感染の痕跡

    西角光平, 河合久仁子, 大西舞衣子, 鳥居恭司, 小林朋子

    第43回日本分子生物学会  2020.12  日本分子生物学会

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    Event date: 2020.12

    Language:Japanese   Presentation type:Poster presentation  

  • ホルマリン固定パラフィン包埋病理組織標本を用いた牛白血病ウイルスの分子疫学的研究

    西角光平、野本帆香、米澤隆弘、野口龍生、村上覚史、 鳥居恭司、小林朋子

    令和元年度日本獣医師会獣医学術学会年次大会(於東京国際フォーラム)  2020.02  日本獣医師会

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    Event date: 2020.02

    Language:Japanese   Presentation type:Oral presentation (general)  

  • 日本における牛白血病の発生と拡散の歴史 Invited

    小林朋子, 西角光平

    六史学会(日本医史・日本薬史・日本獣医史・日本歯科医史・日本看護歴史・洋学史 合同例会)(於順天堂大学)  2019.12  日本六史学会

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    Event date: 2019.12

    Language:Japanese   Presentation type:Oral presentation (general)  

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