Hepatitis B virus surface antigen containing pre-S1 domain (HBsAg (pre-S1))

The **Hepatitis B virus surface antigen containing pre-S1 domain** is the large envelope protein (LHBs) expressed by HBV that includes the N-terminal pre-S1 domain in addition to the pre-S2 and S domains. This domain is essential for HBV infectivity because it contains the primary receptor binding site required for attachment to host hepatocytes, specifically interacting with the sodium taurocholate co-transporting polypeptide (NTCP) receptor on the hepatocyte membrane[1][3]. The pre-S1 domain is myristoylated at its N-terminus, which is crucial for viral entry; mutations or synthetic peptides that interfere with this region block infection. LHBs, along with its truncated forms (MHBs and SHBs), forms the hepatitis B surface antigen (HBsAg), which is a major diagnostic marker and vaccine antigen. Overabundance of surface antigens, particularly in the form of subviral particles, can influence immune responses and contribute to immune tolerance or escape[1][3][5]. Therapeutic strategies target the pre-S1 domain to block viral entry, and it is also considered in improved vaccine designs for broader and stronger immunity.

Other names

Hepatitis B surface antigen large proteinLHBsLarge hepatitis B surface antigenHBV large surface proteinHepatitis B virus large envelope protein

Blocking virus-receptor interaction (NTCP binding inhibition by preS1-derived peptides like bulevirtide)[3]; Inducing neutralizing antibody response (vaccine mechanism); Reducing formation of infectious particles and receptor-mediated entry[3]