B cell receptor complex (BCR complex)

The B cell receptor complex (BCR complex) is a multi-component cell-surface complex essential for B cell development, antigen recognition, and activation of signaling cascades that drive immune responses. Structurally, it consists of a membrane-bound immunoglobulin molecule (mIg), usually of class M, D, G, E, or A, that is responsible for antigen binding, and a signaling moiety comprising an Igα (CD79A) and Igβ (CD79B) heterodimer. These signaling subunits possess immunoreceptor tyrosine-based activation motifs (ITAMs) in their cytoplasmic domains, which are critical for initiating intracellular signaling upon antigen engagement[1][3][9]. The BCR complex is a validated therapeutic target in multiple B cell malignancies, with its signaling pathway inhibited by drugs such as ibrutinib (BTK inhibitor) and idelalisib (PI3Kδ inhibitor), representing a major advance in the treatment of chronic lymphocytic leukemia and other lymphomas[2][4][6]. The BCR not only mediates antigen-specific activation but also provides survival signals to resting B cells and participates in affinity maturation, crucial for effective humoral immunity[7]. Therapy targeting the BCR pathway requires balancing efficacy with the risk of immunosuppression and potential for resistance due to target mutations[4][6].

Other names

B cell antigen receptorB cell receptor (BCR)membrane immunoglobulin complexmIg complexBCR complex

Inhibition of intracellular kinases in the BCR signaling pathway (e.g., BTK, PI3K, SYK) to block B cell activation and survival Disruption of antigen-induced B cell proliferation and survival Suppression of downstream BCR pathway signals (e.g., ITAM phosphorylation, activation of NF-κB and MAPK pathways)