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 rtA181 T/V (WT:-9.63 kcal/mol, rtA181T:-9.30 kcal/mol, rtA181V:-7.96 kcal/mol, rtS78T:-7.37 kcal/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.
Anti-HBV treatment induces novel reverse transcriptase mutations with reflective effect on HBV S antigen / V. Cento, F. Van Hemert, M. Neumann-Fraune, C. Mirabelli, V. Di Maio, R. Salpini, A. Bertoli, V. Micheli, G. Gubertini, S. Romano, M. Visca, G. De Sanctis, B. Berkhout, N. Marino, F. Mazzotta, G. Cappiello, A. Spanò, C. Sarrecchia, F. Ceccherini-Silberstein, M. Andreoni, M. Angelico, J. Verheyen, C.F. Perno, V. Svicher. - In: JOURNAL OF INFECTION. - ISSN 0163-4453. - 67:4(2013), pp. 303-312.
|Titolo:||Anti-HBV treatment induces novel reverse transcriptase mutations with reflective effect on HBV S antigen|
|Parole Chiave:||HBsAg secretion; HBsAg stop codon; HBsAg structure; HBV drug-resistance; Treatment failure; Adenine; Adult; Cell Line; Codon, Nonsense; Drug Resistance, Viral; Female; Gene Expression; Hepatitis B; Hepatitis B Surface Antigens; Hepatitis B virus; Hepatocytes; Humans; Male; Middle Aged; Organophosphonates; Protein Binding; RNA-Directed DNA Polymerase; Reverse Transcriptase Inhibitors; Selection, Genetic; Treatment Failure; Mutation; Microbiology (medical); Infectious Diseases|
|Settore Scientifico Disciplinare:||Settore MED/07 - Microbiologia e Microbiologia Clinica|
|Data di pubblicazione:||2013|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.jinf.2013.05.008|
|Appare nelle tipologie:||01 - Articolo su periodico|