Anti-HBV treatment induces novel reverse transcriptase mutations with reflective effect on HBV S antigen

Valeria Cento, Formijn Van Hemert, Maria Neumann-Fraune, Carmen Mirabelli, Velia Chiara Di Maio, Romina Salpini, Ada Bertoli, Valeria Micheli, Guido Gubertini, Sara Romano, Michela Visca, Giuseppe Maria De Sanctis, Ben Berkhout, Nicoletta Marino, Francesco Mazzotta, Giuseppina Cappiello, Alberto Spanò, Cesare Sarrecchia, Francesca Ceccherini-Silberstein, Massimo AndreoniMario Angelico, Jens Verheyen, Carlo Federico Perno, Valentina Svicher

Research output: Contribution to journalArticlepeer-review


Introduction: The identification of novel reverse-transcriptase (RT) drug-resistance mutations is critical in predicting the probability of success to anti-HBV treatment. Furthermore, due to HBV-RT/HBsAg gene-overlap, they can have an impact on HBsAg-detection and quantification. Methods: 356 full-length HBV-RT sequences from 197 drug-naive patients and 159 patients experiencing virological-breakthrough to nucleoside/nucleotide-analogs (NUCs) were analyzed. Mutants and wild-type HBs-antigens were expressed in HuH7-hepatocytes and quantified in cell-supernatants and cell-lysates by Architect HBsAg-assay. Results: Ten novel RT-mutations (rtN53T-rtS78T-rtS85F-rtS135T-rtA181I-rtA200V-rtK212Q-rtL229V/F-rtM309K) correlated with specific NUC-treatments and classical drug-resistance mutations on divergent evolutionary pathways. Some of them reduced RT-binding affinity for anti-HBV drugs and altered S-antigen structure. Indeed, rtS78T (prevalence: 1.1% in drug-naïve and 12.2% in adefovir-failing patients) decreased the RT-affinity for adefovir more than the classical adefovir-resistance mutations rtA181T/V (WT:-9.63kcal/mol, rtA181T:-9.30kcal/mol, rtA181V:-7.96kcal/mol, rtS78T:-7.37kcal/mol). Moreover, rtS78T introduced a stop-codon at HBsAg-position 69, and completely abrogated HBsAg-quantification in both supernatants and cell-lysates, indicating an impaired HBsAg-secretion/production. Furthermore, the HBsAg-mutation sP217L, silent in RT, significantly correlated with M204V/I-related virological-breakthrough and increased HBsAg-quantification in cell-lysate. Conclusions: Mutations beyond those classically known can affect drug-binding affinity of mutated HBV-RT, and may have potential effects on HBsAg. Their cumulative effect on resistance and HBV-pathogenicity indicates the importance of preventing therapeutic failures.

Original languageEnglish
Pages (from-to)303-312
Number of pages10
JournalJournal of Infection
Issue number4
Publication statusPublished - Oct 2013


  • HBsAg secretion
  • HBsAg stop codon
  • HBsAg structure
  • HBV drug-resistance
  • Treatment failure

ASJC Scopus subject areas

  • Microbiology (medical)
  • Infectious Diseases


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