title: Interferon-γ and Tumor Necrosis Factor-α Produced by T Cells Reduce the HBV Persistence Form, cccDNA, Without Cytolysis.
abstract: OBJECTIVE
  Viral clearance involves immune cell cytolysis of infected cells. However, studies of hepatitis B virus (HBV) infection in chimpanzees have indicated that cytokines released by T cells also can promote viral clearance via noncytolytic processes. We investigated the noncytolytic mechanisms by which T cells eliminate HBV from infected hepatocytes.
  
  
  METHODS
  We performed a cytokine enzyme-linked immunosorbent assay of serum samples from patients with acute and chronic hepatitis B. Liver biopsy specimens were analyzed by in situ hybridization. HepG2-H1.3 cells, HBV-infected HepaRG cells, and primary human hepatocytes were incubated with interferon-γ (IFNγ) or tumor necrosis factor-α (TNF-α), or co-cultured with T cells. We measured markers of HBV replication, including the covalently closed circular DNA (cccDNA).
  
  
  RESULTS
  Levels of IFNγ and TNF-α were increased in serum samples from patients with acute vs chronic hepatitis B and controls. In human hepatocytes with stably replicating HBV, as well as in HBV-infected primary human hepatocytes or HepaRG cells, IFNγ and TNF-α each induced deamination of cccDNA and interfered with its stability; their effects were additive. HBV-specific T cells, through secretion of IFNγ and TNF-α, inhibited HBV replication and reduced cccDNA in infected cells without the direct contact required for cytolysis. Blocking IFNγ and TNF-α after T-cell stimulation prevented the loss of cccDNA. Deprivation of cccDNA required activation of nuclear APOBEC3 deaminases by the cytokines. In liver biopsy specimens from patients with acute hepatitis B, but not chronic hepatitis B or controls, hepatocytes expressed APOBEC3A and APOBEC3B.
  
  
  CONCLUSIONS
  IFNγ and TNF-α, produced by T cells, reduce levels of HBV cccDNA in hepatocytes by inducing deamination and subsequent cccDNA decay.
authors.affiliation: Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany.
authors.forename: Yuchen
authors.initials: Y
authors.lastname: Xia
authors.affiliation: Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Stadler
authors.affiliation: Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany; German Center for Infection Research, Munich and Hannover, Germany.
authors.forename: Julie
authors.initials: J
authors.lastname: Lucifora
authors.affiliation: Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Reisinger
authors.affiliation: Institute for Medical Microbiology, Immunology and Hygiene, University Hospital Cologne, Cologne, Germany.
authors.forename: Dennis
authors.initials: D
authors.lastname: Webb
authors.affiliation: Institute for Medical Microbiology, Immunology and Hygiene, University Hospital Cologne, Cologne, Germany; Center for Molecular Medicine Cologne, University Hospital Cologne, Cologne, Germany.
authors.forename: Marianna
authors.initials: M
authors.lastname: Hösel
authors.affiliation: Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Michler
authors.affiliation: Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany; German Center for Infection Research, Munich and Hannover, Germany.
authors.forename: Karin
authors.initials: K
authors.lastname: Wisskirchen
authors.affiliation: Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Cheng
authors.affiliation: Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany.
authors.forename: Ke
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany.
authors.forename: Wen-Min
authors.initials: WM
authors.lastname: Chou
authors.affiliation: Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany.
authors.forename: Jochen M
authors.initials: JM
authors.lastname: Wettengel
authors.affiliation: Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: Malo
authors.affiliation: Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Bohne
authors.affiliation: Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Hoffmann
authors.affiliation: Medicine II, Department of Clinical Toxicology, University Hospital rechts der Isar of the Technical University of Munich, Munich, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Eyer
authors.affiliation: Department of Medicine II, University Hospital Freiburg, Freiburg, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Thimme
authors.affiliation: German Center for Infection Research, Munich and Hannover, Germany; Abt Transplantationsimmunologie, Medizinische Hochschule Hannover, Hannover, Germany.
authors.forename: Christine S
authors.initials: CS
authors.lastname: Falk
authors.affiliation: Department of General, Visceral, Transplantation, Vascular and Thoracic Surgery, Grosshadern Hospital, Ludwig Maximilians University, Munich, Germany.
authors.forename: Wolfgang E
authors.initials: WE
authors.lastname: Thasler
authors.affiliation: Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Heikenwalder
authors.affiliation: Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany; German Center for Infection Research, Munich and Hannover, Germany. Electronic address: protzer@tum.de.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Protzer
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology; D002478:Cells, Cultured; D018920:Coculture Techniques; D004261:DNA Replication / Q000187:drug effects; D004279:DNA, Viral / Q000187:drug effects / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D056945:Hep G2 Cells / Q000276:immunology / Q000378:metabolism; D016174:Hepacivirus / Q000378:metabolism; D006509:Hepatitis B / Q000378:metabolism* / Q000503:physiopathology; D019694:Hepatitis B, Chronic / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D019562:Viral Load; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D000998:Antiviral Agents; D004279:DNA, Viral; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma
keywords: Apolipoprotein B mRNA Editing Enzyme; HBV Persistence; Immune Regulation; T-Cell Receptor