immunoglobulin complex, circulating IgA immunoglobulin complex IgA immunoglobulin complex, circulating Note that an IgA immunoglobulin complex has the function of antigen binding if a suitable antigen is available. IgA2 antibody 2010-03-24T01:44:53Z GO:0071746 A protein complex composed of two identical immunoglobulin heavy chains of an IgA isotype and two identical immunoglobulin light chains, held together by disulfide bonds, sometimes complexed with J chain or J chain and secretory component, and present in the extracellular space, in mucosal areas or other tissues, or circulating in the blood or lymph. IgA1 antibody IgA antibody cellular_component Ascomycota