immunoglobulin complex IgD immunoglobulin complex cellular_component A protein complex composed of two identical immunoglobulin heavy chains of the IgD isotype and two identical immunoglobulin light chains, held together by disulfide bonds. An IgD 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. Note that an IgD immunoglobulin complex has the function of antigen binding if a suitable antigen is available. 2010-03-24T01:44:53Z GO:0071738