Immunoglobulin D (IgD) is an antibody class primarily functioning as a membrane-bound receptor on the surface of naïve B cells. Comprising less than 1% of serum immunoglobulins, IgD exists mainly in a transmembrane form that co-expresses with IgM on mature B lymphocytes. It plays a crucial role in B cell activation, survival, and immune surveillance by sensing environmental antigens and regulating humoral immune responses. Recent studies reveal IgD's involvement in mucosal immunity and its ability to bind to basophils and mast cells, triggering antimicrobial defense. Structurally, IgD features an extended hinge region, making it susceptible to proteolytic cleavage. Despite being discovered in 1965, IgD's precise functions remain an active area of immunological research. The immunogen for this antibody is Eg7410, and the immunogen sequence targets the Fc region of porcine IgD.