B-cell antigen receptor (BCR)

The **B-cell antigen receptor (BCR)** is a multiprotein complex expressed on the surface of B lymphocytes; it is responsible for the recognition of specific antigens and transduction of activation signals into the cell. The BCR consists of membrane-bound immunoglobulin (*IgM*, *IgD*, or class-switched isotypes) that binds antigen, and the signaling subunits **Igα (CD79A)** and **Igβ (CD79B)**, which contain ITAM motifs that initiate intracellular signaling cascades on antigen binding[1][5][7]. Upon activation, B cells proliferate and differentiate into antibody-secreting plasma cells and memory cells, central to adaptive humoral immunity[1][3][8]. BCR activation may be T-cell dependent (involving presentation to helper T cells via MHC II and CD40-CD40L interactions) or T-cell independent (via cross-linking of receptors by repetitive antigens)[5][6]. Aberrant BCR signaling is linked to diseases such as lymphoproliferative malignancies and autoimmune disorders, making BCR and its signaling molecules key therapeutic targets.

Other names

BCRB-cell receptorB cell antigen receptorB-lymphocyte receptor

Inhibition of BCR signaling pathways (e.g., BTK inhibitors), B-cell depletion via targeting CD20, blocking proliferation and survival, antibody-dependent cellular cytotoxicity