Which class of immunoglobulin functions as an antigenic receptor site on the surface of immature B lymphocytes?

Which class of immunoglobulin functions as an antigenic receptor site on the surface of immature B lymphocytes?

• A. IgM
• B. IgG
• C. IgD
• D. IgA

Answer: (C)

The immunoglobulin that functions as an antigenic receptor site on the surface of immature B lymphocytes is IgD. This type of immunoglobulin is crucial for B cell development and maturation. In immature B cells, IgD's presence on the surface plays a fundamental role in recognizing antigens. When these B cells are exposed to specific antigens, they can become activated and differentiate into plasma cells or memory B cells. While IgM is also expressed on the surface of B cells, primarily during the later stages of B cell development, it is IgD that is uniquely associated with the early stages of B cell maturation, serving as a receptor that facilitates the initial signaling events necessary for B cell activation. IgG and IgA, on the other hand, are primarily involved in immune response and are produced after B cells have differentiated into plasma cells, not in the initial stages of B cell activation. Thus, IgD's presence signifies the readiness of an immature B cell to engage with specific antigens and initiate the immune response.

The immunoglobulin that functions as an antigenic receptor site on the surface of immature B lymphocytes is IgD. This type of immunoglobulin is crucial for B cell development and maturation. In immature B cells, IgD's presence on the surface plays a fundamental role in recognizing antigens. When these B cells are exposed to specific antigens, they can become activated and differentiate into plasma cells or memory B cells.

While IgM is also expressed on the surface of B cells, primarily during the later stages of B cell development, it is IgD that is uniquely associated with the early stages of B cell maturation, serving as a receptor that facilitates the initial signaling events necessary for B cell activation. IgG and IgA, on the other hand, are primarily involved in immune response and are produced after B cells have differentiated into plasma cells, not in the initial stages of B cell activation. Thus, IgD's presence signifies the readiness of an immature B cell to engage with specific antigens and initiate the immune response.