IgD is an antibody isotype with specific roles in the immune system.
Understanding IgD
IgD (Immunoglobulin D) is an antibody that exists in two forms:
- Membrane-bound IgD: Found on the surface of immature B lymphocytes (B cells).
- Secreted IgD: Present in small quantities in the blood serum.
Key Characteristics of IgD
| Feature | Description |
|---|---|
| Type | Monomeric antibody isotype |
| Location | Plasma membranes of immature B-lymphocytes and in small amounts as a secreted form in blood serum. |
| Structure | Composed of two heavy chains (delta class) and two light chains. |
| Primary Role | Found on the surface of B cells, IgD is believed to play a role in B-cell activation and differentiation. |
Role of IgD on B Cells
IgD is co-expressed with IgM on the surface of most mature, but naive, B cells. While its precise function is still under investigation, it's believed to participate in B cell activation when the B cell receptor binds to an antigen. This activation can then lead to B cell differentiation into plasma cells, which produce antibodies, or memory B cells, which provide long-term immunity.
