A unique amino acid substitution, L215Q, in the hepatitis B virus small envelope protein of a genotype F isolate that inhibits secretion of hepatitis B virus subviral particles.

Abstract

The small (S) envelope protein is the major component of hepatitis B virus surface antigen (HBsAg). Some mutations in the S-HBsAg coding region may cause deficiency in the secretion of both viral and empty subviral particles (SVPs) and lead to accumulation of HBsAg inside the cells. In this study, we identified a unique amino acid substitution (L215Q) in the carboxyl-terminal end of S-HBsAg of an HBV genotype F isolate that provoked an inhibitory effect on secretion of SVPs. HBsAg levels were measured daily by enzyme-linked immunosorbent assay in the medium and cell extracts of HuH7 and CHO cells transiently transfected with plasmids containing wild-type or mutated S-HBsAg gene. Wild-type HBsAg was detectable in both medium and cell extracts of transfected cells. In contrast, extracellular levels of mutant HBsAg were not higher than cut-off values. By immunofluorescence with monoclonal antibody, it was shown that wild-type HBsAg was distributed throughout the cytoplasm, whereas mutant HBsAg was concentrated around the nucleus, suggesting retention in the endoplasmic reticulum. Amino acid substitutions that inhibit HBsAg secretion, such as that characterized in this study (L215Q), should have implications in HBV immunological diagnostics.

DOI: 10.1159/000127430

Cite this paper

@article{Araujo2008AUA, title={A unique amino acid substitution, L215Q, in the hepatitis B virus small envelope protein of a genotype F isolate that inhibits secretion of hepatitis B virus subviral particles.}, author={Natalia Motta Araujo and Carlos Ot{\'a}vio Alves Vianna and Caroline Cordeiro Soares and Selma de Andrade Gomes}, journal={Intervirology}, year={2008}, volume={51 2}, pages={81-6} }