► Molecular weight of IgD is185, 000 Daltons and has a sedimentation coefficient of 7S.

► Its concentration in serum is about 3 mg/100ml, which constitutes about 0.2% of total Ig.

► It is mostly intra vascular in distribution.

► Its half-life is about 3days.

► It is rich in carbohydrates.

► IgD along with IgM occurs on the surface of unstimulated or mature B cells and serves as a reorganization receptor for antigens.

► No biological effect or function has been identified for IgD.