Hepatitis B virus core antigen (HBcAg) (HBcAg)

Hepatitis B virus core antigen (HBcAg) is the primary structural protein that assembles to form the icosahedral nucleocapsid of the Hepatitis B virus. It plays a fundamental role in the viral lifecycle by encapsidating the pre-genomic RNA (pgRNA) and viral polymerase, a process essential for subsequent reverse transcription and DNA synthesis (UniProt P03146). HBcAg is highly immunogenic and contains several well-characterized B-cell and T-cell epitopes that are central to the host's immune response against HBV (PubMed: 28938214). In chronic hepatitis B, the T-cell response to these epitopes is often impaired or exhausted, leading to viral persistence. Consequently, HBcAg is a major target for therapeutic vaccines designed to restore immune control and for core protein allosteric modulators (CpAMs) that disrupt capsid assembly (PubMed: 31554340). These drugs bind to the core protein dimers, leading to the formation of empty or aberrant capsids that cannot support viral replication. Monitoring antibodies against HBcAg epitopes remains a cornerstone of clinical diagnostics to differentiate between various stages of HBV infection.

Other names

HBV core proteinCapsid proteinp21cHepatitis B core antigenHBcCore antigen epitopes

Inhibition of viral capsid assembly and pre-genomic RNA packaging through allosteric modulation of core protein dimers, or induction of specific T-cell responses via therapeutic vaccination.