B-cell receptor specific for hepatitis B surface antigen (HBsAg-specific BCR)

The B-cell receptor specific for hepatitis B surface antigen (HBsAg-specific BCR) is a membrane-bound immunoglobulin complex on the surface of B lymphocytes that specifically recognizes and binds to the surface proteins of the Hepatitis B virus (HBV). This receptor is the primary mediator of the humoral immune response against HBV, as its activation triggers the differentiation of B cells into plasma cells that secrete neutralizing anti-HBs antibodies. These antibodies are essential for viral clearance and the prevention of infection by blocking viral entry into hepatocytes (Neumann-Haefelin et al., 2018). In patients with chronic hepatitis B (CHB), HBsAg-specific B cells often exhibit a dysfunctional or 'exhausted' phenotype, characterized by the expression of inhibitory receptors like PD-1 and a failure to produce sufficient neutralizing antibodies (Liver Int., 2017). This B-cell dysfunction is a major barrier to achieving a functional cure for HBV. Consequently, the HBsAg-specific BCR is a key target for therapeutic vaccines and other immunotherapies aimed at restoring B-cell function. Current drugs interacting with this target include prophylactic and therapeutic vaccines that act as agonists to stimulate the receptor and initiate the protective immune cascade (ClinicalTrials.gov). Research is also exploring the use of these BCR sequences to engineer CAR-T cells or to develop novel monoclonal antibodies for passive immunization.

Other names

HBsAg-specific B-cell receptorAnti-HBs B-cell receptorHepatitis B surface antigen-specific B-cell receptorHBsAg-specific BCR

Agonism of the B-cell receptor (BCR) through antigen binding, leading to receptor clustering and activation of downstream signaling pathways (e.g., via CD79A/B and Syk), which promotes B-cell proliferation, affinity maturation, and differentiation into anti-HBs-secreting plasma cells (Neumann-Haefelin et al., 2018; Liver Int., 2017).