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Anti-TAPA-1 (CD81) Antibody, clone 5A6

clone 5A6, from mouse

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CD81 antigen, 26 kDa cell surface protein TAPA-1, Target of the antiproliferative antibody 1, Tetraspanin-28, Tspan-28

biological source


Quality Level

antibody form

purified immunoglobulin

antibody product type

primary antibodies


5A6, monoclonal

species reactivity



antibody small pack of 25 μL


flow cytometry: suitable
immunoprecipitation (IP): suitable
inhibition assay: suitable
western blot: suitable



NCBI accession no.

UniProt accession no.

shipped in


target post-translational modification


Gene Information

human ... CD81(975)

Related Categories

General description

CD81 antigen (UniProt: P60033; also known as 26 kDa cell surface protein TAPA-1, Target of the antiproliferative antibody 1, Tetraspanin-28, Tspan-28, CD81) is encoded by the CD81 (also known as TAPA1, TSPAN28) gene (Gene ID: 975) in human. TAPA-1 is a nonglycosylated, homodimeric, multi-pass membrane protein of the tetraspanin (TM4SF) family. It is expressed in a wide range of cells, including hematolymphoid, neuroectodermal, and mesenchymal tumor cell lines and is reported to play a role in the regulation of lymphoma cell growth. It contains four transmembrane domains, two extracellular loops, and short amino and carboxyl termini that are intracellular. TAPA-1 is shown to affect cell adhesion, morphology, activation, proliferation, and differentiation of B, T, and other cells. On B cells it is a part of a complex involving CD21, CD19, and Leu13 and this complex is reported to reduce the threshold for B cell activation via the B cell receptor by bridging antigen specific recognition and CD21-mediated complement recognition. On T cells, it is shown to associate with CD4 and CD8 and provides a costimulatory signal with CD3. It is also reported to act as a receptor for hepatitis C virus (HCV) in hepatocytes. Mutations in CD81 gene cause common variable immunodeficiency 6 (CVID6) that is characterized by antibody deficiency, hypogammaglobulinemia, recurrent bacterial infections, and an inability to mount an antibody response to antigen. (Levy S., et al. (1998). Annu. Rev. Immunol.16; 89-109; Oren, R., et al. (1990). Mol. Cell Biol. 10(8); 4007-15).


Clone 5A6 detects TAPA-1 (CD81) in human cells.


OCI-LY8 whole cells (Cellosaurus cell line).


Anti-TAPA-1 (CD81), clone 5A6, Cat. No. MABF2061, is a mouse monoclonal antibody that detects TAPA-1 (CD81) and has been tested for use in Flow Cytometry, Inhibition assay, Immunoprecipitation and Western Blotting.
Research Category
Inflammation & Immunology
Western Blotting Analysis: A representative lot detected TAPA-1 (CD81) in Western Blotting applications (Clark, K.L., et. al. (2004). J Biol Chem. 279(19):19401-6).

Immunoprecipitation Analysis: A representative lot immunoprecipitated TAPA-1 (CD81) in Immunoprecipitation applications (Clark, K.L., et. al. (2004). J Biol Chem. 279(19):19401-6; Oren, R., et. al. (1990). Mol Cell Biol. 10(8):4007-15).

Flow Cytometry Analysis: A representative lot detected TAPA-1 (CD81) in Flow Cytometry applications (van Zelm, M.C., et. al. (2010). J Clin Invest. 120(4):1265-74; Oren, R., et. al. (1990). Mol Cell Biol. 10(8):4007-15).

Inhibition: A representative lot inhibited the growth and proliferation of OCI-LY8 cell line. (Oren, R., et. al. (1990). Mol Cell Biol. 10(8):4007-15).


Evaluated by Flow Cytometry in HUH-7 cells.

Flow Cytometry Analysis: 1 µg of this antibody detected TAPA-1 (CD81) in one million HUH-7 cells.

Target description

25.81 kDa calculated.

Physical form

Format: Purified
Protein G purified
Purified mouse monoclonal antibody IgG1 containing PBS without azide.

Storage and Stability

Stable for 1 year at -20°C from date of receipt. Handling Recommendations: Upon receipt and prior to removing the cap, centrifuge the vial and gently mix the solution. Aliquot into microcentrifuge tubes and store at -20°C. Avoid repeated freeze/thaw cycles, which may damage IgG and affect product performance.

Other Notes

Concentration: Please refer to lot specific datasheet.


Unless otherwise stated in our catalog or other company documentation accompanying the product(s), our products are intended for research use only and are not to be used for any other purpose, which includes but is not limited to, unauthorized commercial uses, in vitro diagnostic uses, ex vivo or in vivo therapeutic uses or any type of consumption or application to humans or animals.

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