immunoglobulin complex, circulating IgG immunoglobulin complex IgG immunoglobulin complex, circulating GO:0071736 IgG3 antibody Note that an IgG immunoglobulin complex has the function of antigen binding if a suitable antigen is available. Also, IgG isotypes vary by species. IgG4 antibody IgG2a antibody IgG antibody 2010-03-24T01:44:53Z IgG1 antibody IgG2b antibody IgG2c antibody A protein complex composed of two identical immunoglobulin heavy chains of an IgG isotype and two identical immunoglobulin light chains, held together by disulfide bonds, and present in the extracellular space, in mucosal areas or other tissues, or circulating in the blood or lymph. cellular_component IgG2 antibody Ascomycota