B cell receptor and antibody (BCR (for B cell receptor); Ab or Ig (for antibody))

B cell receptors are membrane-bound immunoglobulins on the surface of B lymphocytes, consisting of two identical heavy chains and two identical light chains forming a Y-shaped molecule. The variable regions at the tips of the Y confer antigen specificity, while constant regions determine immunological function and class. When BCRs bind antigens, they initiate signaling via associated Igα and Igβ subunits containing ITAMs, leading to B cell activation, proliferation, and differentiation. Activated B cells become plasma cells that secrete soluble antibodies—these retain the same antigen specificity as the BCR but lack the membrane-anchoring region. Antibodies neutralize pathogens, tag them for destruction, and orchestrate immune defense. The structure and function of BCRs and antibodies are central to adaptive immunity and underpin vaccine efficacy and many immunotherapies. Therapeutic targeting of BCRs and antibody pathways is effective in B cell malignancies, autoimmunity, and transplantation.

Other names

Immunoglobulin (Ig)membrane immunoglobulin (mIg)antibodyBCR

Inhibition of B cell activation (block BCR-mediated signal transduction); Depletion of B cells (via antibody-dependent cellular cytotoxicity); Interference with antibody production; Suppression of autoantibody generation.