Selection of a secretion-incompetent mutant in the serum of a patient with severe hepatitis B1 1The authors thank S. Polywka and R. Laufs for measuring HBsAg as well as Prof. W. Gerlich (University Giessen, Germany) and I. K. Mushahwar (Abbott Laboratories) for providing monoclonal antibodies 18/07 and H166, respectively.

Kalinina, Tatyana; Riu, Anna; Fischer, Lutz; Santantonio, Theresa; Will, Hans; Sterneck, Martina

doi:10.1016/s0016-5085(03)01202-2

Cited by 11 publications

(2 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results of previous studies suggested that the G145R mutation reduced the ability of viral assembly and secretion [26,27]. In this study, however, the levels of serum transaminases had been elevated and the levels of HBV DNA had remained high for several years in the girl infected with the G145R mutant, which was detected by the mutant-specific real-time PCR.…”

Section: Discussioncontrasting

confidence: 53%

Hepatitis B surface gene 145 mutant as a minor population in hepatitis B virus carriers

et al. 2012

View full text Add to dashboard Cite

BackgroundHepatitis B virus (HBV) can have mutations that include the a determinant, which causes breakthrough infection. In particular, a single mutation at amino acid 145 of the surface protein (G145) is frequently reported in the failure of prophylactic treatment. The aim of this study was to evaluate the frequency of the a determinant mutants, especially the G145 variant, in Japan, where universal vaccination has not been adopted.MethodsThe present study was a retrospective study. The study cohorts were defined as follows: group 1, children with failure to prevent mother-to-child transmission despite immunoprophylaxis (n = 18, male/female = 8/10, age 1-14 years; median 6 years); group 2, HBV carriers who had not received vaccination or hepatitis B immunoglobulin (n = 107, male/female = 107, age 1-52 years; median 16 years). To detect the G145R and G145A mutants in patients, we designed 3 probes for real-time PCR. We also performed direct sequencing and cloning of PCR products.ResultsBy mutant-specific real-time PCR, one subject (5.6%) was positive for the G145R mutant in group 1, while the G145 mutant was undetectable in group 2. The a determinant mutants were detected in one (5.6%) of the group 1 subjects and 10 (9.3%) of the group 2 subjects using direct sequencing, but direct sequencing did not reveal the G145 mutant as a predominant strain in the two groups. However, the subject who was positive according to the mutant-specific real-time PCR in group 1 had overlapped peaks at nt 587 in the electropherogram. In group 2, 11 patients had overlapped peaks at nt 587 in the electropherogram. Cloning of PCR products allowed detection of the G145R mutant as a minor strain in 7 (group 1: 1 subject, group 2: 6 subjects) of 12 subjects who had overlapped peaks at nt 587 in the electropherogram.ConclusionsThe frequency of the a determinant mutants was not high in Japan. However, the G145R mutant was often present as a minor population in children and adults. HBV carriers might have the a determinant mutants as a minor form.

show abstract

Section: Discussioncontrasting

confidence: 53%

Hepatitis B surface gene 145 mutant as a minor population in hepatitis B virus carriers

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Vaccine-and passive immunoprophylaxis-associated escape mutations are often located between aa137 and 147, with G145R being most frequently reported [8,23]. While single amino acid substitutions in the S protein (such as K141E and G145R) can be sufficient to escape neutralizing antibodies against SHBs (anti-HBs), they often concomitantly cause a decrease in virion secretion efficiency [10,24,25]. Furthermore, substitutions and insertions that lead to novel N-linked glycosylation motifs (sequons; N-X-S/T) have been frequently reported [26,27].…”

Section: Introductionmentioning

confidence: 99%

A Novel Insertion in the Hepatitis B Virus Surface Protein Leading to Hyperglycosylation Causes Diagnostic and Immune Escape

Lehmann

Slanina

Roderfeld

et al. 2023

Viruses

View full text Add to dashboard Cite

Chronic hepatitis B virus (HBV) infection is a global health threat. Mutations in the surface antigen of HBV (HBsAg) may alter its antigenicity, infectivity, and transmissibility. A patient positive for HBV DNA and detectable but low-level HBsAg in parallel with anti-HBs suggested the presence of immune and/or diagnostic escape variants. To support this hypothesis, serum-derived HBs gene sequences were amplified and cloned for sequencing, which revealed infection with exclusively non-wildtype HBV subgenotype (sgt) D3. Three distinct mutations in the antigenic loop of HBsAg that caused additional N-glycosylation were found in the variant sequences, including a previously undescribed six-nucleotide insertion. Cellular and secreted HBsAg was analyzed for N-glycosylation in Western blot after expression in human hepatoma cells. Secreted HBsAg was also subjected to four widely used, state-of-the-art diagnostic assays, which all failed to detect the hyperglycosylated insertion variant. Additionally, the recognition of mutant HBsAg by vaccine- and natural infection-induced anti-HBs antibodies was severely impaired. Taken together, these data suggest that the novel six-nucleotide insertion as well as two other previously described mutations causing hyperglycosylation in combination with immune escape mutations have a critical impact on in vitro diagnostics and likely increase the risk of breakthrough infection by evasion of vaccine-induced immunity.

show abstract

Impact of hepatitis B virus (HBV) preS/S genomic variability on HBV surface antigen and HBV DNA serum levels

et al. 2012

View full text Add to dashboard Cite

To evaluate whether hepatitis B virus (HBV) preS/S gene variability has any impact on serum hepatitis B surface antigen (HBsAg) levels and to analyze the replication capacity of naturally occurring preS/S variants, sera from 40 untreated patients with HBV-related chronic liver disease (hepatitis B e antigen [HBeAg]-positive, n 5 11; HBeAg-negative, n 5 29) were virologically characterized. Additionally, phenotypic analysis of three different preS/S variant isolates (carrying a 183-nucleotide deletion within the preS1 region, the deletion of preS2 start codon, and a stop signal at codon 182 within the S gene, respectively) was performed. HBV infecting 14 (35%) patients had single or multiple preS/S genomic mutations (i.e., preS1 and/or preS2 deletions, preS2 start codon mutations, C-terminally truncated and/or ''a'' determinant mutated S protein). Presence of preS/S variants negatively correlated with HBsAg titers (r 5 20.431; P 5 0.005) and its prevalence did not significantly differ between HBeAg-positive and HBeAg-negative patients. No correlation was found between HBsAg and HBV DNA levels in patients infected with preS/S mutants, whereas a significant correlation was found between HBsAg and viremia levels (r 5 0.607; P 5 0.001) in patients infected with wild-type HBV strains. HepG2 cells replicating the abovementioned three preS/S variants showed significant reduction of HBsAg secretion, retention of envelope proteins in the endoplasmic reticulum, less efficient virion secretion and nuclear accumulation of significantly higher amounts of covalently closed circular DNA compared with wild-type HBV replicating cells. Conclusion: In patients infected with preS/S variants, HBV DNA replication and HBsAg synthesis/secretion appear to be dissociated. Therefore, the use of HBsAg titer as diagnostic/prognostic tool has to take into account the frequent emergence of preS/S variants in chronic HBV infection. (HEPATOLOGY 2012;56:434-443) See Editorial on Page 411 H epatitis B virus (HBV) belongs to the Hepadnaviridae family, which comprises hepatotropic DNA viruses sharing with HBV most of the genetic structure and replicative characteristics. 1 HBV is one of the smallest viruses in nature and its genome presents a highly compact genetic organization. It consists of a partially double-stranded relaxed circular DNA of approximately 3,200 nucleotides in length and contains four partially overlapping open-reading frames: preS/S, pre-C-C, P, and X. The preS/S openreading frame encodes three different, structurally related envelope proteins termed the large (L), middle (M), and small (S) protein that are synthesized from alternative initiation codons. The three proteins share the same carboxy-terminus part but have different aminoterminal extensions. In particular, the S protein-corresponding to the HBV surface antigen (HBsAg)-consists of only 226 amino acids (aa), the M protein contains an extra N-terminal extension of 55 aa, and the L

show abstract

Cited by 11 publications

References 24 publications

Hepatitis B surface gene 145 mutant as a minor population in hepatitis B virus carriers

Hepatitis B surface gene 145 mutant as a minor population in hepatitis B virus carriers

A Novel Insertion in the Hepatitis B Virus Surface Protein Leading to Hyperglycosylation Causes Diagnostic and Immune Escape

Impact of hepatitis B virus (HBV) preS/S genomic variability on HBV surface antigen and HBV DNA serum levels

Contact Info

Product

Resources

About