immunoglobulin complex B cell receptor complex cellular_component B lymphocyte receptor complex antibody GO:0042570 BCR complex An immunoglobulin complex that is present in the plasma membrane of B cells and that in its canonical form is composed of two identical immunoglobulin heavy chains and two identical immunoglobulin light chains and a signaling subunit, a heterodimer of the Ig-alpha and Ig-beta proteins. Note that an immunoglobulin complex has the function of antigen binding if a suitable antigen is available. B-cell receptor complex immunoglobulin complex, membrane bound B cell receptor complex B cell receptor accessory molecule complex GO:0019815 B-lymphocyte receptor complex plasma membrane signaling receptor complex adaptive immune receptor