immunoglobulin complex A protein complex that in its canonical form is composed of two identical immunoglobulin heavy chains and two identical immunoglobulin light chains, held together by disulfide bonds and sometimes complexed with additional proteins. An immunoglobulin complex may be embedded in the plasma membrane or present in the extracellular space, in mucosal areas or other tissues, or circulating in the blood or lymph. GO:0019814 Note that an immunoglobulin complex has the function of antigen binding if a suitable antigen is available. cellular_component go.owl obi.owl protein complex