FITC Mouse Anti-Human IgD Antibody (S-3287)

Immunoglobulin D (IgD) is an antibody isotype that, in humans, exists primarily as a monomeric, heavily glycosylated membrane-bound receptor on naïve B cells, where it partners with membrane IgM to form the B-cell antigen receptor (BCR) complex that initiates adaptive immune responses upon antigen engagement; it is encoded by the IGH@ locus on chromosome 14, generated through alternative mRNA splicing downstream of IgM, and although secreted IgD is scarce in serum (≈30 µg/mL with a half-life of ~2.8 days), it can be elicited by T-cell–independent stimuli such as interleukin-27 or BAFF and functions through binding to the lectin-like receptor CD44 on basophils and mast cells to trigger antimicrobial and anti-allergic responses, while its hinge region is uniquely elongated and O-glycosylated, imparting flexibility for antigen recognition yet rendering it highly susceptible to proteolysis, and recent evidence indicates that IgD also participates in mucosal immunity via interactions with commensal bacteria and contributes to the development and homeostasis of B-cell subsets, including marginal zone and B-1 cells.