Browsing by Author "Levrero, Massimo"

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    A global scientific strategy to cure hepatitis B
    (Elsevier, 2019-07) Revill, Peter A.; Chisari, Francis V.; Block, Joan M.; Dandri, Maura; Gehring, Adam J.; Guo, Haitao; Hu, Jianming; Kramvis, Anna; Lampertico, Pietro; Janssen, Harry L. A.; Levrero, Massimo; Li, Wenhui; Liang, T. Jake; Lim, Seng-Gee; Lu, Fengmin; Penicaud, M. Capucine; Tavis, John E.; Thimme, Robert; Zoulim, Fabien; Microbiology and Immunology, School of Medicine
    Chronic hepatitis B virus (HBV) infection is a global public health challenge on the same scale as tuberculosis, HIV, and malaria. The International Coalition to Eliminate HBV (ICE-HBV) is a coalition of experts dedicated to accelerating the discovery of a cure for chronic hepatitis B. Following extensive consultation with more than 50 scientists from across the globe, as well as key stakeholders including people affected by HBV, we have identified gaps in our current knowledge and new strategies and tools that are required to achieve HBV cure. We believe that research must focus on the discovery of interventional strategies that will permanently reduce the number of productively infected cells or permanently silence the covalently closed circular DNA in those cells, and that will stimulate HBV-specific host immune responses which mimic spontaneous resolution of HBV infection. There is also a pressing need for the establishment of repositories of standardised HBV reagents and protocols that can be accessed by all HBV researchers throughout the world. The HBV cure research agenda outlined in this position paper will contribute markedly to the goal of eliminating HBV infection worldwide.
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    Quantification of the hepatitis B virus cccDNA: evidence-based guidelines for monitoring the key obstacle of HBV cure
    (BMJ, 2023) Allweiss, Lena; Testoni, Barbara; Yu, Mei; Lucifora, Julie; Ko, Chunkyu; Qu, Bingqian; Lütgehetmann, Marc; Guo, Haitao; Urban, Stephan; Fletcher, Simon P.; Protzer, Ulrike; Levrero, Massimo; Zoulim, Fabien; Dandri, Maura; Microbiology and Immunology, School of Medicine
    Objectives: A major goal of curative hepatitis B virus (HBV) treatments is the reduction or inactivation of intrahepatic viral covalently closed circular DNA (cccDNA). Hence, precise cccDNA quantification is essential in preclinical and clinical studies. Southern blot (SB) permits cccDNA visualisation but lacks sensitivity and is very laborious. Quantitative PCR (qPCR) has no such limitations but inaccurate quantification due to codetection of viral replicative intermediates (RI) can occur. The use of different samples, preservation conditions, DNA extraction, nuclease digestion methods and qPCR strategies has hindered standardisation. Within the ICE-HBV consortium, available and novel protocols for cccDNA isolation and qPCR quantification in liver tissues and cell cultures were compared in six laboratories to develop evidence-based guidance for best practices. Design: Reference material (HBV-infected humanised mouse livers and HepG2-NTCP cells) was exchanged for cross-validation. Each group compared different DNA extraction methods (Hirt extraction, total DNA extraction with or without proteinase K treatment (+PK/-PK)) and nuclease digestion protocols (plasmid-safe ATP-dependent DNase (PSD), T5 exonuclease, exonucleases I/III). Samples were analysed by qPCR and SB. Results: Hirt and -PK extraction reduced coexisting RI forms. However, both cccDNA and the protein-free relaxed circular HBV DNA (pf-rcDNA) form were detected by qPCR. T5 and Exo I/III nucleases efficiently removed all RI forms. In contrast, PSD did not digest pf-rcDNA, but was less prone to induce cccDNA overdigestion. In stabilised tissues (eg, Allprotect), nucleases had detrimental effects on cccDNA. Conclusions: We present here a comprehensive evidence-based guidance for optimising, controlling and validating cccDNA measurements using available qPCR assays.