Lehmann, FelixFelixLehmannSlanina, HeikoHeikoSlaninaRoderfeld, MartinMartinRoderfeldRoeb, ElkeElkeRoebTrebicka, JonelJonelTrebickaZiebuhr, JohnJohnZiebuhrGerlich, Wolfram H.Wolfram H.GerlichSchüttler, Christian G.Christian G.SchüttlerSchlevogt, BernhardBernhardSchlevogtGlebe, DieterDieterGlebe2023-04-132023-04-132023https://jlupub.ub.uni-giessen.de/handle/jlupub/16199http://dx.doi.org/10.22029/jlupub-15581Chronic 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, serumderived 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 vaccineinduced immunity.enNamensnennung 4.0 Internationalhepatitis B virusN-linked glycosylationdiagnostic escapeimmune escapeddc:610