IgD Structure and Function

Immunoglobulin D (IgD)

IgD is membrane bound immunoglobulins they are found on a surface of mature naive B-cells.

• Structurally Immunoglobulin D (IgD) is a monomer. 

• It has 2 Delta(δ) heavy chains and two light chains.

• Each heavy chain has three constant domains.

• Molecular weight of IgD is 180 kDa.

• The hinge region of IgD is longest among all antibody classes.

• IgD is mostly remains membrane bound.

• IgD is one of the main receptors on mature B cells. it is found on the surface of these cells in addition of IgM which together form the part of B cell receptor complex.

• IgD make up less than 1% of the antibody in the serum(0.4mg/ml).

• It has a half-life of only 3 days.

Functions of Ig D
Functions of IgD are unknown but it seems that they play important role in recognition of antigens by B-cells.
  Ig D carries out antigen recognition by B-cells. Combination of cell membrane bound Ig D with the corresponding antigen leads to specific stimulation of the B cell either activation or cloning to produce antibody, or suppression.