Hepatitis B surface antibody (Anti-HBs) (Anti-HBs)

Hepatitis B surface antibodies (Anti-HBs) are protective proteins produced by the immune system in response to the Hepatitis B surface antigen (HBsAg). These antibodies are generated following either a natural infection with the Hepatitis B virus (HBV) or through active immunization with recombinant vaccines. The primary biological function of Anti-HBs is to neutralize the virus by binding to the 'a' determinant of the HBsAg protein on the viral envelope, which prevents the virus from attaching to and entering host hepatocytes (StatPearls, 2023). In clinical practice, the presence and concentration of Anti-HBs are used as a definitive biomarker to assess a person's immunity to HBV, with a titer of 10 mIU/mL or higher generally considered to provide long-term protection (CDC, 2023). Therapeutically, these antibodies are administered as Hepatitis B immune globulin (HBIG) to provide immediate passive immunity in post-exposure scenarios, such as needle-stick injuries or to prevent mother-to-child transmission. However, the effectiveness of Anti-HBs can be compromised by the emergence of viral escape mutants, which possess structural variations in the HBsAg protein that allow the virus to evade antibody-mediated neutralization (PubMed: 22244529).

Other names

HBsAbAnti-HBsAgHepatitis B virus surface antibodyAntibody to Hepatitis B surface antigen

Anti-HBs antibodies provide immunity by binding to the 'a' determinant of the Hepatitis B surface antigen (HBsAg) located on the viral envelope. This binding neutralizes the Hepatitis B virus (HBV) by sterically hindering its ability to attach to and enter host hepatocytes via the sodium taurocholate cotransporting polypeptide (NTCP) receptor (StatPearls, 2023; PubMed: 26071611).