IgD Antibodies

Structure of IgD

IgD is an immunoglobulin with a molecular weight of approximately 185 kDa, and its molecular weight varies to some extent among different species. This protein is composed of two heavy chains (δ chains, approximately 55 kDa) and two light chains (κ or λ chains, approximately 25 kDa) linked by disulfide bonds.

IgD has a unique hinge region structure, which is rich in O-glycosylation sites but also makes it prone to degradation by proteases at the same time. Its heavy chain contains three constant regions (Cδ1-Cδ3) and one variable region, and the antigen recognition function is achieved through the Fab segment. It is worth noting that human IgD is often co-expressed with IgM on the surface of B cells, forming a double BCR complex. The three-dimensional structure of this protein presents a typical "Y" type antibody conformation, but its longer hinge region endows the structure with higher flexibility. During the activation process of B cells, IgD binds to specific receptors through its Fc segment and participates in signal transduction. Recent studies have found that certain pathogens (such as Streptococcus pneumoniae) can produce specific IGD-binding proteins, suggesting their special role in infection immunity.

Fig. 1 Overall structure of the IgD Fab.¹

Key structural properties of IgD:

• Typical "Y" type antibody structure
• Unique super-long hinge area
• Rich in O-glycosylation modification sites
• Membrane-bound and secretory forms exist

Functions of IgD

The main function of IgD is related to immune regulation, and its special functions are mainly reflected in B cell activation and mucosal immunity:

IgD has the characteristics of co-expression with IgM to form a dual antigen recognition system, temperature sensitivity that is prone to detach from the surface of B cells at 37 °C, evolutionary features conserved in all mammals, and clinical features that abnormal levels are associated with autoimmune diseases and lymphoma. The latest research also found that secretory IgD can participate in mucosal immune surveillance by binding to immune cells such as mast cells.

Applications of IgD and IgD Antibody in Literature

1. Davies, Anna M., et al. "The Crystal Structure of Human IgD-Fc Reveals Unexpected Differences With Other Antibody Isotypes." Proteins: Structure, Function, and Bioinformatics 93.4 (2025): 786-800. https://doi.org/10.1002/prot.26771

This article indicates that the latest research findings show that IGD-FC has a unique structure, and its orientation of the Cδ3 domain and interface characteristics are significantly different from those of other antibody subtypes. There are special binding pockets at the Cδ2/Cδ3 interface, which may play a key role in maintaining the stability of IgD dimers.

2. Dirks, Johannes, et al. "IgD shapes the pre-immune naïve B cell compartment in humans." Frontiers in Immunology 14 (2023): 1096019. https://doi.org/10.3389/fimmu.2023.1096019

This article indicates that although IgD deletion does not affect the generation of initial B cells, it can change the expression of surface markers such as CD19/CD21, resulting in a weakened response of B cells to BCR/TLR signals and affecting the selection of specific VH regions, suggesting that IgD plays a key role in regulating the survival of self-reactive B cell clones.

3. Kasahara, Taissa de M., and Sudhir Gupta. "IgD+ IgM− B Cells in Common Variable Immunodeficiency." Pathogens 13.2 (2024): 136. https://doi.org/10.3390/pathogens13020136

This article indicates that in patients with common variant immunodeficiency disease (CVID), the proportion of IgD+IgM- memory B cells significantly increases when combined with allergic rhinitis/asthma, suggesting that such cells may play a special role in respiratory allergic reactions, while the function of IgD+IgM-CD27- non-reactive B cells remains normal.

4. Sabouri, Zahra, et al. "IgD attenuates the IgM-induced anergy response in transitional and mature B cells." Nature communications 7.1 (2016): 13381. https://doi.org/10.1038/ncomms13381

This article indicates that IgD maintains the survival of non-reactive B cells by reducing its own antigen reactivity: When B cells express only IgD, although calcium signaling and the expression of core non-responsive genes can be normally induced, compared with the co-expression state of IgM-IgD, the expression of IgD alone will enhance the expression of tolerance markers such as Syndecan-1, thereby inhibiting excessive autoimmune responses and protecting the diversity of the antibody library.

5. Noviski, Mark, et al. "IgM and IgD B cell receptors differentially respond to endogenous antigens and control B cell fate." Elife 7 (2018): e35074. https://doi.org/10.7554/eLife.35074

Studies have found that although IgD can effectively conduct BCR signals in vitro, its reactivity to self-antigens in vivo is significantly lower than that of IgM. Experiments show that B cells expressing only IgD cannot differentiate into short-life plasma cells, and the production of autoantibodies is limited. This indicates that IgD maintains the resting state of autoreactive B cells by reducing the activation threshold of them, thereby inhibiting the occurrence of autoimmune reactions.

Creative Biolabs: IgD Antibodies for Research

Creative Biolabs specializes in the production of high-quality IgD antibodies for research and industrial applications. Our portfolio includes monoclonal antibodies tailored for ELISA, Western Blot (WB), Flow Cytometry (FC), and Immunohistochemistry (IHC), and other diagnostic methodologies.

• Custom IgD Antibody Development: Tailor-made solutions to meet specific research requirements.
• Bulk Production: Large-scale antibody manufacturing for industry partners.
• Technical Support: Expert consultation for protocol optimization and troubleshooting.
• Aliquoting Services: Conveniently sized aliquots for long-term storage and consistent experimental outcomes.

For more details on our IgD antibodies, custom preparations, or technical support, contact us at info@creative-biolabs.com.