title: Modulation of regulatory T-cell activity in combination with interleukin-12 increases hepatic tolerogenicity in woodchucks with chronic hepatitis B.
abstract: Regulatory T cells (Treg) play a critical role in the modulation of immune responses to viral antigens in chronic viral hepatitis. Woodchucks (Marmota monax) infected with the woodchuck hepatitis virus (WHV) represent the best animal model for chronic hepatitis B virus (HBV) infection. Examination of intrahepatic and peripheral Treg in uninfected and WHV chronically infected woodchucks showed a significant increase of intrahepatic Treg numbers in chronically infected animals, whereas no differences were found in peripheral blood. In agreement with these data, higher expression levels of Forkhead box P3 (Foxp3), interleukin (IL)-10, transforming growth factor beta (TGF-β) were detected in the liver of chronic WHV carriers in comparison to uninfected animals. Furthermore, treatment of WHV-infected animals with an adenovirus encoding IL-12 failed to reduce viral load, a finding that was associated with lymphocyte unresponsiveness to IL-12 stimulation in vitro. We observed that TGF-β and Treg play a major role in the lack of lymphocyte response to IL-12 stimulation, as TGF-β inhibition and Treg depletion allowed recovery of T-cell responsiveness to this cytokine. Based on these results, woodchucks were treated with IL-12 in combination with a TGF-β inhibitory peptide or Treg depletion. However, no antiviral effect was achieved and, instead, an enhancement of the intrahepatic tolerogenic environment was observed.
  
  
  CONCLUSIONS
  Our data show that TGF-β inhibition or Treg depletion had no added benefit over IL-12 therapy in chronic WHV infection. IL-12 immunostimulation induces a strong immunosuppressive reaction in the liver of chronic WHV carriers that counteracts the antiviral effect of the treatment.
authors.affiliation: Centro de Investigación Medica Aplicada (CIMA), Division of Hepatology and Gene Therapy, University of Navarra, Pamplona, Spain.
authors.forename: Itziar
authors.initials: I
authors.lastname: Otano
authors.forename: Lester
authors.initials: L
authors.lastname: Suarez
authors.forename: Javier
authors.initials: J
authors.lastname: Dotor
authors.forename: Manuela
authors.initials: M
authors.lastname: Gonzalez-Aparicio
authors.forename: Julien
authors.initials: J
authors.lastname: Crettaz
authors.forename: Cristina
authors.initials: C
authors.lastname: Olagüe
authors.forename: Africal
authors.initials: A
authors.lastname: Vales
authors.forename: Jose Ignacio
authors.initials: JI
authors.lastname: Riezu
authors.forename: Esther
authors.initials: E
authors.lastname: Larrea
authors.forename: Francisco
authors.initials: F
authors.lastname: Borras
authors.forename: Alberto
authors.initials: A
authors.lastname: Benito
authors.forename: Ruben
authors.initials: R
authors.lastname: Hernandez-Alcoceba
authors.forename: Stephan
authors.initials: S
authors.lastname: Menne
authors.forename: Jesús
authors.initials: J
authors.lastname: Prieto
authors.forename: Gloria
authors.initials: G
authors.lastname: González-Aseguinolaza
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000276:immunology; D006528:Carcinoma, Hepatocellular; D045744:Cell Line, Tumor; D003520:Cyclophosphamide / Q000494:pharmacology; D004359:Drug Therapy, Combination; D017919:Hepatitis B Virus, Woodchuck / Q000187:drug effects* / Q000276:immunology; D019694:Hepatitis B, Chronic / Q000188:drug therapy* / Q000276:immunology; D007108:Immune Tolerance / Q000187:drug effects* / Q000276:immunology; D007166:Immunosuppressive Agents / Q000494:pharmacology; D018664:Interleukin-12 / Q000276:immunology / Q000494:pharmacology*; D008113:Liver Neoplasms; D008392:Marmota; D010455:Peptides / Q000276:immunology / Q000494:pharmacology; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects* / Q000276:immunology / Q000821:virology; D053773:Transforming Growth Factor beta1 / Q000276:immunology / Q000494:pharmacology
chemical_list: D000956:Antigens, Viral; D007166:Immunosuppressive Agents; C562050:P17 peptide; D010455:Peptides; D053773:Transforming Growth Factor beta1; D018664:Interleukin-12; D003520:Cyclophosphamide