Rabbit anti-Human CD81 Monoclonal Antibody for FC - P60033

Core Product Specifications and Parameters

Biological Background: CD81 Function and Localization

• CD81 (Target of the antiproliferative antibody 1, TAPA-1, Tetraspanin-28) is a 26 kDa cell surface protein and a member of the tetraspanin superfamily, characterized by four transmembrane domains and critical roles in membrane microdomain organization.
• It acts as a structural component of tetraspanin-enriched microdomains (TERMs), essential for B cell receptor complex assembly and lowering the antigen threshold for clonal expansion and antibody production. In B cells, CD81 facilitates trafficking and compartmentalization of CD19, enabling the formation of CD19-CR2/CD21-BCR complexes within signaling TERMs. Related references: PMID:16449649, PMID:20237408, PMID:27881302, PMID:15161911
• In T cells, CD81 localizes CD247/CD3 zeta to antigen-induced synapses with B cells, providing costimulation and driving polarization toward a T helper type 2 phenotype. Related references: PMID:22307619, PMID:23858057, PMID:8766544
• CD81 is present in MHC class II compartments, suggesting a modulatory role in antigen presentation. Related references: PMID:8409388, PMID:8766544
• As a regulator of cell-cell fusion, CD81 inhibits macrophage fusion into multinucleated giant cells and is implicated in sperm-egg fusion and myoblast fusion. Related references: PMID:12796480
• CD81 is exploited by multiple pathogens: it is a receptor for hepatitis C virus (HCV) entry into hepatocytes, supports early HIV-1 replication in T cells by promoting SAMHD1 degradation, and is specifically required for Plasmodium falciparum sporozoite infectivity of hepatocytes. Related references: PMID:28871089
• Subcellularly, CD81 localizes to the cell membrane and basolateral cell membrane, with tissue expression predominantly on B cells, hepatocytes, monocytes/macrophages, and both naïve and memory CD4-positive T cells. Related references: PMID:20237408, PMID:12483205, PMID:12796480, PMID:22307619

Experimental Guidance and Technical Tips

• The immunogen spans amino acids 114–199 of human CD81, located within the large extracellular loop (LEL), a region critical for protein–protein interactions and viral binding. This design may enhance recognition of native CD81.
• This conjugate is intended for direct flow cytometry (FC). Include appropriate isotype controls and perform antibody titration to determine optimal staining concentration.
• For detection of CD81, consider using human PBMCs, B cell lines (e.g., Raji), or hepatocyte-derived cell lines, as CD81 is expressed on B cells, T cells, and hepatocytes.
• In multicolor FC panels, ensure spectral compatibility of with other fluorophores and incorporate a viability dye to exclude dead cells.
• Validate antibody performance in your specific experimental context, including fixation and permeabilization steps if intracellular staining is pursued.

CamelBio: Your One-Stop Sourcing Bridge

CamelBio provides diagnostic manufacturers and researchers with comprehensive access to IVD raw materials, including validated antibody pairs, optimized monoclonal antibodies, and bulk ancillary reagents. This anti-CD81 antibody supports immunology and infectious disease research, and CamelBio can assist with sourcing of related tetraspanin targets and custom raw-material procurement. Reach out to streamline your supply chain for CD81 and other key membrane protein reagents.