Why is IgD found mostly on the surface of developing B cells?

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Diagram of an antibody molecule showing two identical light chains and two identical heavy chains joined by disulfide bonds in a Y-shaped structure, with labeled regions for antigen binding and effector function. — antibody The four-chain structure of an antibody, or immunoglobulin, molecule. The basic unit is composed of two identical light (L) chains and two identical heavy (H) chains, which are held together by disulfide bonds to form a flexible Y shape. Each chain is composed of a variable (V) region and a constant (C) region.

IgD molecules are primarily found on the surface of developing B cells, though they are rarely released into the circulation. While the exact biological function of IgD remains unclear, it is hypothesized that it may play a role in determining whether specific antigens successfully activate B cells.1