Recombinant Hepatitis D Virus protein

Supplementary information

This supplementary information is collated from multiple sources and compiled automatically.

Hepatitis D Virus (HDV) also known as delta virus is a small circular RNA virus. It is unique among viruses because it requires the presence of Hepatitis B Virus (HBV) for its replication and infection cycle. The delta protein encoded by the HDV RNA genome has an important role in its replication. The delta protein typically has a mass of approximately 24 kDa and is expressed specifically in the liver cells of infected individuals. Due to its dependence on HBV HDV is classified within the family of Deltaviridae.

Biological function summary

The delta protein interacts with host cellular machinery to facilitate HDV replication. It is part of a ribonucleoprotein complex that consists of the viral RNA and the delta protein itself. The complex enables the replication of the viral genome and packaging of the mature virus. The HDV RNA acts as both a template for replication and a ribozyme allowing it to self-cleave and process into the mature genomic RNA. The delta protein in its large form is essential for encapsidation with the HBV surface antigens completing the assembly of infectious virus particles.

Pathways

Hepatitis D virus follows a unique co-infective pathway relying heavily on the HBV lifecycle. The interaction between the HDV delta protein and HBV surface antigens particularly the large HBV surface antigen plays an important role in the assembly and secretion of new virions. HDV actively manipulates the host cellular pathways to facilitate its replication and requires the host's RNA polymerase II for synthesizing its RNA genome. The HBV-associated pathogenesis further accentuates liver damage caused by co-infection.

HDV infection significantly contributes to severe liver diseases including fulminant hepatitis and liver cirrhosis and it increases the risk of hepatocellular carcinoma in affected patients. The combined infection of HDV and HBV leads to a more aggressive disease course and the presence of HBV proteins especially the surface antigen is necessary for HDV propagation. Research into hepatitis D antibodies targets these viral proteins to develop novel therapeutic strategies and prevent liver disease progression.