BZellRezeptor

BZellRezeptor is a transmembrane receptor complex on B lymphocytes that recognizes antigen and initiates adaptive immune responses. It functions as the B cell receptor (BCR) system, composing a membrane-bound immunoglobulin with specific antigen-binding capacity and signaling components that translate recognition into cellular activation.

The BZellRezeptor consists of a membrane-bound immunoglobulin molecule (IgM or IgD) that binds antigen, associated with the Igα/Igβ signaling heterodimer (CD79a/CD79b) containing immunoreceptor tyrosine-based activation motifs (ITAMs). This complex conveys the binding event to the cell interior, initiating signal transduction necessary for B cell responses.

Upon antigen binding, the BZellRezeptor clusters and triggers intracellular signaling, leading to calcium mobilization and activation of kinases that drive B cell proliferation and differentiation into plasma cells and memory B cells. The receptor also mediates endocytosis of bound antigen for processing and presentation on MHC class II molecules to helper T cells, enabling T-dependent antibody responses.

Signal propagation involves Src-family kinases (such as LYN), Syk, PLCγ2, and downstream pathways including NF-κB, NFAT, and MAP kinases. Coreceptors such as CD19 and CD21 amplify signaling, while inhibitory receptors like CD22 and FcγRIIB provide negative regulation to prevent overactivation.

Dysfunction of BZellRezeptor signaling is associated with immunodeficiencies and B cell malignancies. Therapeutic strategies target BZellRezeptor signaling, including Bruton’s tyrosine kinase inhibitors (for example, ibrutinib) and PI3K inhibitors, used in cancer and some autoimmune conditions.