Which is a primary functional role of IgD?

Which is a primary functional role of IgD?

• A. Part of B Cell Receptor
• B. Activates Basophils and Mast Cells
• C. Responds to Parasitic Reactions
• D. Secreted in Breast Milk

Answer: (A)

IgD’s main job is to act as a membrane-bound antibody that forms the B cell receptor on naive mature B cells, usually paired with IgM on the cell surface. This receptor recognizes antigens and transmits activation signals through the BCR complex, triggering B cell activation, clonal expansion, and eventual antibody production after class switching. The soluble form of IgD is present at low levels and isn’t the primary defender like IgA in secretions, IgG systemically, or IgE in parasitic and allergic responses. While IgD can participate in other immune interactions, its primary and defining role is as part of the B cell receptor.

IgD’s main job is to act as a membrane-bound antibody that forms the B cell receptor on naive mature B cells, usually paired with IgM on the cell surface. This receptor recognizes antigens and transmits activation signals through the BCR complex, triggering B cell activation, clonal expansion, and eventual antibody production after class switching. The soluble form of IgD is present at low levels and isn’t the primary defender like IgA in secretions, IgG systemically, or IgE in parasitic and allergic responses. While IgD can participate in other immune interactions, its primary and defining role is as part of the B cell receptor.