Hepatitis B surface antigen-binding protein (SBP)

Hepatitis B surface antigen-binding protein (SBP) is a human-derived protein, approximately 344 amino acids in length, that specifically interacts with the preS region of the Hepatitis B virus (HBV) surface antigen (HBsAg). Identified from human liver cDNA libraries, SBP is structurally identical to the constant region of immunoglobulin G (IgG) and is localized on the plasma membrane of hepatocytes, where it acts as a candidate receptor or co-receptor mediating HBV entry. Beyond its role in the viral life cycle, SBP has gained significant attention as a potent vaccine adjuvant; its ability to facilitate the uptake of HBsAg by dendritic cells significantly enhances the immunogenicity of Hepatitis B vaccines. In clinical contexts, SBP is associated with the pathogenesis of chronic HBV infection and the development of hepatocellular carcinoma. Current therapeutic research focuses on utilizing SBP to improve vaccine efficacy and developing SBP-targeted inhibitors to block viral infection at the entry stage.

Other names

SBPHBsAg-BPHBsAg-binding proteinIgG constant region-like proteinApolipoprotein HEndonexin IIAldolase BEnoyl-CoA hydratase 1

SBP binds to the preS region of the Hepatitis B surface antigen (HBsAg), facilitating viral attachment and entry into hepatocytes. When used as a vaccine adjuvant, it enhances the delivery and presentation of HBsAg to dendritic cells, thereby boosting the immune response.