Elimination of cccDNA by genome editing by using HBV-infected mice

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K09427
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Gastroenterology
• Research Institution: Hiroshima University
• Principal Investigator: Imamura Michio 広島大学, 病院(医), 講師 (40403513)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: B型肝炎 / cccDNA / ヒト肝細胞移植マウス / 末梢血単核球

Outline of Final Research Achievements

High-dose combination therapy with six weeks of entecavir plus PEG-IFN for hepatitis B virus (HBV)-infected human hepatocyte transplanted uPA/SCID mice resulted in persistently negative HBV DNA in serum. Serum HBsAg and hepatitis B corerelated antigen (HBcrAg) continued to decrease and eventually became negative at 12 weeks after cessation of the therapy. Persistent loss of serum HBV DNA and loss of HBV markers by entecavir and PEG-IFN combination treatment in mice suggests that control of HBV can be achieved even in the absence of a cellular immune response. We generated new immunodeficiency cDNA-uPA/Rag2-/-/Jak3-/- mice with humanized livers that were almost completely repopulated with human hepatocytes and succeeded in HBV infection to these mice. Co-culture of PBMCs with human hepatocyte and anti-CD80/CD86 antibodies before administration to mice resulted in an establishment of human CD45-positive mononuclear cell chimerism with reduction of allo-immunity.

Free Research Field

ウイルス性肝炎

Academic Significance and Societal Importance of the Research Achievements

HBV感染マウスに抗ウイルス薬を投与することで肝内cccDNAを十分に低下させることが可能であった。今後、抗ウイルス薬と免疫調整薬を組み合わせることにより肝内cccDNAを消失させる治療法開発が期待される。cDNA-uPA/Rag2-/-/Jak3-/-マウスを用いてヒトPBMCの生着が可能であった。今後さらに生着したPBMCのプロファイルの解析、HBV特異的CTLの有無、肝線維化発症の有無などの検討が必要である。B型肝炎モデルマウスの構築は、B型慢性肝炎に対する根治的治療法開発に有用である。