VMC 221: Veterinary Immunology and Serology (1+1)

IMMUNOGLOBULIN D (Ig D)

• It is secreted by plasma cells in spleen and lymph nodes. It has two δ heavy chains and two light chains (either κ or λ) with molecular weight of 180 KDa (7S).
• Mouse IgD lacks C_H2 domain and hinge region separates this two domains. But cattle, sheep, pig and humans have 3 constant domains C_H1 to C_H3.
• It has no interchain disulphide bonds. It is susceptible to proteolytic enzymes and thus could not be detected in serum but found in low concentration in plasma.

Functions

• It is not found in all animal species
• Function is not well established