Immunoglobulin D (IgD) is an antibody isotype that makes up about 1% of proteins in the plasma membranes of immature B-lymphocytes where it is usually co-expressed with another cell surface antibody called IgM. IgD is also produced in a secreted form that is found in very small amounts in blood serum, representing 0.25% of immunoglobulins in serum. The relative molecular mass and half-life of secreted IgD is 185 kDa and 2.8 days, respectively.[1] Secreted IgD is produced as a monomeric antibody with two heavy chains of the delta (δ) class, and two Ig light chains.
- ^ Rogentine GN, Rowe DS, Bradley J, Waldmann TA, Fahey JL (1966). "Metabolism of human immunoglobulin D (IgD)". J. Clin. Invest. 45 (9): 1467–78. doi:10.1172/JCI105454. PMC 292826. PMID 5919348.