HBsAg mutations related to occult hepatitis B virus infection in HIV‐positive patients result in a reduced secretion and conformational changes of HBsAg

Abstract

Mutations in the "a" determinant region of HBV as often found in OBI remarkably impair the detection of HBsAg from serum and infected cells, emphasizing the relevance of alternative methods such as HBV-DNA quantification for high-risk groups like HIV-infected individuals. J. Med. Virol. 89:246-256, 2017. © 2016 Wiley Periodicals, Inc.

Molecular and serological characterization of occult hepatitis B virus infection among patients with hemophilia

“…In the present study, 62.5% of the subjects who were determined as OBI case had detectable viral load; the mean viral load was 4.5 × 10 2 copies/mL. This result is consistent with most of the reported viral loads among the OBI cases . Very low and undetectable viral loads of OBI along with some mutations that may decrease viral secretion represent a repressive force.…”

“…P120A has been previously described as a defective phenotype for both detection and infectivity of the virus, and introduced as an OBI‐relevant mutation . Functional in vitro evidence revealed some reduced level of antigenicity for P127T, and same effects were also established for Q129H, the most prevalent escape mutant observed in the present study. It has also been prevalent in previous reports carried out in Iran .…”

“…The “a” determinant in the MHR region of HBV surface Aghas flexible loops which comprises a hydrophilic feature that interact with antibodies (Ab). Thus, any mutation disturbing this conformational space between the alpha‐helixes may impair the interaction between Ab and Ag . The exact Function of R73H and I110L is yet to be fully understood, however, these codons lie within the region that specifies epitopes of surface protein .…”

Epidemiology, risk factors, and molecular characterization of occult hepatitis B infection among anti‐hepatitis B core antigen alone subjects

“…It this study P105A has seen in 23.8% of OBI cases, this position was previously introduced critical for replication of HBV and is associated to occurrence of OBI . S136P that was detected in one subject, has been previously introduced as a hot position for OBI …”

“…32 S136P that was detected in one subject, has been previously introduced as a hot position for OBI. 35 As S gene completely is in overlap with Pol gene, there were mutations in the corresponding region of RT, such as L80I, S85F, R110G, and L91I, which were repeatedly reported in previous studies as resistance associated. 31,36 Positions of RT at 80, 85, 91, and 110 are functional in the first domain of RT and are potentially prone to resistance in the presence of mutations.…”