title: DNA vaccination in combination or not with lamivudine treatment breaks humoral immune tolerance and enhances cccDNA clearance in the duck model of chronic hepatitis B virus infection.
abstract: This study used a duck hepatitis B virus (DHBV) model to evaluate whether a novel DNA vaccination protocol alone or associated with antiviral (lamivudine) treatment was able to clear the intrahepatic covalently closed, circular viral DNA (cccDNA) pool responsible for persistence of infection. DHBV carriers received DNA vaccine (on weeks 6, 10, 13, 14, 28 and 35) targeting the large envelope and/or core proteins alone or combined with lamivudine treatment (on weeks 1-8) or lamivudine monotherapy. After 10 months of follow-up, a dramatic decrease in viraemia and liver DHBV cccDNA (below 0.08 cccDNA copies per cell) was observed in 9/30 ducks (30 %) receiving DNA mono- or combination therapy, compared with 0/12 (0 %) from lamivudine monotherapy or the control groups, suggesting a significant antiviral effect of DNA immunization. However, association with the drug did not significantly improve DHBV DNA vaccine efficacy (33 % cccDNA clearance for the combination vs 27 % for DNA monotherapy), probably due to the low antiviral potency of lamivudine in the duck model. Seroconversion to anti-preS was observed in 6/9 (67 %) ducks showing cccDNA clearance, compared with 1/28 (3.6 %) without clearance, suggesting a significant correlation (P<0.001) between humoral response restoration and cccDNA elimination. Importantly, an early (weeks 10-12) drop in viraemia was observed in seroconverted animals, and virus replication did not rebound following the cessation of immunotherapy, indicating a sustained effect. This study provides the first evidence that therapeutic DNA vaccination is able to enhance hepadnaviral cccDNA clearance, which is tightly associated with a break in humoral immune tolerance. These results also highlight the importance of antiviral drug potency and an effective DNA immunization protocol for the design of therapeutic vaccines against chronic hepatitis B.
authors.affiliation: Université Lyon 1, IFR62, F-69008 Lyon, France.|INSERM, Unit 871, F-69424 Lyon, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Thermet
authors.affiliation: Ecole Nationale Vétérinaire de Lyon, F-69280 Marcy l'Etoile, France.|Université Lyon 1, IFR62, F-69008 Lyon, France.|INSERM, Unit 871, F-69424 Lyon, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Buronfosse
authors.affiliation: Université Lyon 1, IFR62, F-69008 Lyon, France.|INSERM, Unit 871, F-69424 Lyon, France.
authors.forename: Bettina
authors.initials: B
authors.lastname: Werle-Lapostolle
authors.affiliation: Pathology Department, Marcel Mérieux Laboratory, F-69007 Lyon, France.
authors.forename: Michele
authors.initials: M
authors.lastname: Chevallier
authors.affiliation: Hospices Civiles de Lyon, Department of Hepatology, Hotel-Dieu, F-69002 Lyon, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Pradat
authors.affiliation: Hospices Civiles de Lyon, Department of Hepatology, Hotel-Dieu, F-69002 Lyon, France.|Université Lyon 1, IFR62, F-69008 Lyon, France.|INSERM, Unit 871, F-69424 Lyon, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Trepo
authors.affiliation: Hospices Civiles de Lyon, Department of Hepatology, Hotel-Dieu, F-69002 Lyon, France.|Université Lyon 1, IFR62, F-69008 Lyon, France.|INSERM, Unit 871, F-69424 Lyon, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Zoulim
authors.affiliation: Université Lyon 1, IFR62, F-69008 Lyon, France.|INSERM, Unit 871, F-69424 Lyon, France.
authors.forename: Lucyna
authors.initials: L
authors.lastname: Cova
mesh_terms: D000818:Animals; D004279:DNA, Viral / Q000235:genetics; D004372:Ducks; D005500:Follow-Up Studies; D018347:Hepadnaviridae Infections / Q000276:immunology*; D006510:Hepatitis B Antibodies / Q000097:blood; D006512:Hepatitis B Core Antigens / Q000235:genetics / Q000276:immunology; D015611:Hepatitis B Virus, Duck / Q000235:genetics / Q000276:immunology*; D006524:Hepatitis, Viral, Animal / Q000276:immunology*; D007108:Immune Tolerance; D019259:Lamivudine / Q000627:therapeutic use*; D008099:Liver / Q000821:virology; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology*; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology; D014766:Viremia
chemical_list: D004279:DNA, Viral; D006510:Hepatitis B Antibodies; D006512:Hepatitis B Core Antigens; C096362:L protein, hepatitis B virus; D019444:Vaccines, DNA; D014759:Viral Envelope Proteins; D019259:Lamivudine