CD81 Antibodies

Structure of CD81

CD81 is a transmembrane protein with a molecular weight of approximately 25-26 kDa. Its molecular weight varies slightly among different cell types due to the degree of glycosylation modification.

This protein is composed of 228 amino acids, forming four highly conserved transmembrane domains. Its molecular structure consists of two extracellular rings (EC1 and EC2), among which the larger EC2 ring forms a stable spherical domain through disulfide bonds. The EC2 loop has specific hydrophobic regions and glycosylation sites that directly participate in protein-protein interactions. Palmitoylation modification in the near-membrane region enhanced the stability of CD81 on the plasma membrane, while the interaction in the transmembrane region promoted the formation of tetramer complexes. These structural features jointly determined its functions in cell signal transduction and viral invasion.

Fig. 1 Schematic representation of the tetraspanin CD81.¹

Key structural properties of CD81:

• Four times across the membrane structure field of typical stents
• Large extracellular two-rings form molecular interaction interfaces
• Conserved palmitoylation sites regulate membrane segregation and signal transduction

Functions of CD81

The core function of the CD81 gene-encoded protein is to act as a cell membrane organizer, regulating cell signaling and adhesion by forming a tetramer network. Its main physiological and pathological functions are as follows:

The interaction between CD81 and ligands shows spatial specificity, and the conformational changes of its extracellular ring directly determine the binding activity. This characteristic not only explains its regulatory role in the immune response but also reveals the molecular basis of the virus's utilization of host receptors.

Applications of CD81 and CD81 Antibody in Literature

1. Fan, Yé, et al. "Differential proteomics argues against a general role for CD9, CD81 or CD63 in the sorting of proteins into extracellular vesicles." Journal of Extracellular Vesicles 12.8 (2023): 12352. https://doi.org/10.1002/jev2.12352

The article indicates that in MCF7 cells, CD81 and CD9 are mainly co-localized in the plasma membrane, and CD81 has a higher enrichment degree in extracellular vesicles (EVs). Studies have found that the absence of CD9 and CD81 has little effect on the protein composition of EVs, but they jointly regulate the contents of their direct binding proteins CD9P-1 and EWI-2 in EVs. The latter is mainly caused by the decrease in cell expression levels.

2. Gurrieri, Elena, et al. "CD81-guided heterologous EVs present heterogeneous interactions with breast cancer cells." Journal of Biomedical Science 31.1 (2024): 92. https://doi.org/10.1186/s12929-024-01084-9

The study aimed to construct engineered extracellular vesicles (EVs) targeting HER2 using CD81 as a scaffold. This EV can specifically bind to HER2-positive cancer cells and effectively deliver therapeutic cargo such as doxorubicin or long-chain mRNA. It has shown enhanced targeted killing effects in both in vitro and in mouse models, providing a basis for the CD81-based EV targeted therapy platform.

3. Cone, Allaura S., et al. "CD81 fusion alters SARS-CoV-2 Spike trafficking." Mbio 15.9 (2024): e01922-24. https://doi.org/10.1128/mbio.01922-24

The study fused the S protein of the novel coronavirus with the transmembrane protein CD81, successfully redirecting and enriching the degradation pathway of the S protein in extracellular vesicles (EVs). This CD81-S fusion EV can produce in large quantities, bind to ACE2, and effectively induce anti-S antibodies in mice, providing a path for the design of new vaccines.

4. Fénéant, Lucie, Shoshana Levy, and Laurence Cocquerel. "CD81 and hepatitis C virus (HCV) infection." Viruses 6.2 (2014): 535-572. https://doi.org/10.3390/v6020535

The article indicates that the invasion of hepatitis C virus (HCV) into liver cells is a complex multi-step process, among which the four-transmembrane protein CD81 is one of the most clearly defined key invasion factors. This review elaborates in detail on the core role of CD81 in the HCV life cycle and the antiviral immune response of the body.

5. Zona, Laetitia, et al. "CD81-receptor associations—impact for hepatitis C virus entry and antiviral therapies." Viruses 6.2 (2014): 875-892. https://doi.org/10.3390/v6020875

The article indicates that the four-transmembrane protein CD81 plays a key role in the process of HCV invasion of hepatocytes by forming specific microdomains with other membrane proteins. This invasion process is complex and requires the synergistic action of multiple host factors such as CD81 and scavenger receptor BI. Research on this complex provides new ideas for the prevention and treatment of HCV infection.

Creative Biolabs: CD81 Antibodies for Research

Creative Biolabs specializes in the production of high-quality CD81 antibodies for research and industrial applications. Our portfolio includes monoclonal antibodies tailored for ELISA, Flow Cytometry, Western blot, immunohistochemistry, and other diagnostic methodologies.

• Custom CD81 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 CD81 antibodies, custom preparations, or technical support, contact us at email.