B-cell receptor recognizing the 'a' determinant of hepatitis B surface antigen (BCR-anti-HBs)

The B-cell receptor (BCR) recognizing the 'a' determinant of the hepatitis B surface antigen (HBsAg) is a specialized membrane-bound immunoglobulin essential for the humoral immune response against the hepatitis B virus (HBV). The 'a' determinant is a complex, conformational epitope located within the major hydrophilic region (MHR) of the HBsAg protein, typically encompassing amino acid residues 124 to 147 (Salpini et al., 2015, PubMed: 25533591). When these specific BCRs bind to the 'a' determinant, they initiate intracellular signaling pathways that lead to B-cell proliferation and differentiation into plasma cells that secrete high-affinity neutralizing antibodies (anti-HBs). These antibodies are critical for viral clearance and long-term immunity, as they neutralize the virus by preventing its attachment to the sodium taurocholate cotransporting polypeptide (NTCP) receptor on hepatocytes (Yan et al., 2012, PubMed: 23145388). In chronic HBV infection, B cells specific to this epitope often exhibit an exhausted phenotype, characterized by impaired effector functions and low antibody production (Salimzadeh et al., 2018, PubMed: 29343445). Therapeutic strategies, including recombinant vaccines and novel immunotherapies, aim to stimulate or restore the activity of these BCRs to achieve a functional cure. However, mutations within the 'a' determinant can result in 'immune escape,' where the virus evades recognition by both vaccine-induced antibodies and the host's BCR repertoire (Carman et al., 1990, PubMed: 2144736).

Other names

HBsAg-specific B-cell receptorAnti-HBs B-cell receptora-determinant specific B-cell receptorHepatitis B surface antigen-specific B-cell receptor

Antigen-mediated activation of B-cells through BCR signaling, leading to clonal expansion and secretion of neutralizing anti-HBs antibodies.