CD9, CD63, and CD81 are tetraspanin family proteins enriched on the surface of endosome-derived EVs. They are present at high copy number and conserved across human and rodent species. Standard Western blot and flow cytometry can detect them reliably. MISEV2018 designates them as category 1 EV-associated transmembrane proteins, making them the most widely accepted identity markers in the field.
Extracellular Vesicles / Exosomes
Exosome Marker Antibodies for CD63, CD81, CD9, TSG101 and ALIX Detection
Exosome marker antibodies for CD63, CD81, CD9, TSG101 and ALIX detection
When you are characterising extracellular vesicle populations, antibodies against tetraspanins CD9, CD63, and CD81 give you a fast route to the ISEV-recommended multi-marker panel. Adding ESCRT-pathway markers TSG101 and ALIX completes this panel for Western blot and flow cytometry. These markers support EV characterisation, but they cannot by themselves prove endosomal biogenesis. A preparation that is positive for tetraspanins is best described as a marker-positive EV subset in your sample, not confirmed proof of origin.
Bundled antibody kits supply rabbit antibodies against CD9, CD63, CD81, and Hsp70 in a single purchase, reducing lot-to-lot variability across your four-marker panel.
Individual rabbit antibodies against TSG101 and Vimentin are validated for human, mouse, and rat samples, giving you flexibility across species. They are available with a goat anti-rabbit HRP secondary for immediate Western blot use. Positive protein controls, including human and mouse exosome lysates, support assay qualification. Multiplex antibody arrays extend single-marker ELISA, giving you simultaneous profiling of surface proteins across multiple EV subpopulations.
Choose your exosome antibody format by assay type and marker panel.
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Assay type. Western blot: individual primary antibodies or multi-marker antibody bundles validated for WB give you a direct route. Flow cytometry: each antibody's flow-cytometry validation is listed on its product datasheet, so you can confirm flow-validated formats before use. Multiplex surface profiling: antibody array formats that detect multiple tetraspanin and cargo markers simultaneously.
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Marker breadth. Single marker: individual antibodies against TSG101, ALIX, CD9, CD63, CD81, Vimentin, or Hsp70 let you target exactly what is needed. Four-marker panel (CD9, CD63, CD81, Hsp70): bundled antibody kits are more economical than four individual orders. Custom or broader panel: antibody arrays cover extended EV surface marker sets in a single assay.
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Species. Most exosome marker antibodies are validated for human, mouse, and rat, and the product datasheet gives you species reactivity data before you order for non-standard species.
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Controls. Human and mouse exosome lysate positive controls are available separately, giving you a qualification standard for Western blot.
Applications
Western blot characterisation
EV marker antibodies detect TSG101, ALIX, CD9, CD63, CD81, or HSP70 in your preparation. Pairing them with HRP-conjugated secondaries gives you immediate blotting.
Flow cytometry profiling
These antibodies profile marker-positive EV subsets by flow cytometry, though small EVs below scatter threshold need high-sensitivity or bead-capture methods.
Multiplex surface antigen profiling
Antibody arrays measure surface antigen expression across multiple markers, giving you a broader profile than single-marker assays. Array formats extend this further.
EV origin verification
Tetraspanin positivity supports, but does not confirm, endosomal biogenesis, so pairing it with particle sizing and contaminant controls gives you more than standalone proof.
Biomarker discovery
Antibody arrays compare tetraspanin and cargo abundance between disease and healthy plasma EV preparations, guided by exosome quantification assays.
Assay qualification
Validated positive-control lysates from characterised cell line EV preparations serve as qualification standards for Western blot method development.
Product Catalog
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Exosome Antibodies & Antibody Arrays
Tetraspanin & ESCRT Antibodies for Exosome Marker Characterisation
Frequently asked questions
Both TSG101 and ALIX are cytoplasmic proteins associated with the ESCRT machinery. This machinery sorts cargo into multivesicular bodies during exosome biogenesis. TSG101 is a component of ESCRT-I; ALIX links ESCRT-III to membrane budding. Together they confirm that a preparation contains endosomally derived vesicles. Detecting both alongside tetraspanins provides orthogonal evidence of EV identity.
Standard flow cytometry has a detection limit of approximately 300 nm. This means most small EVs in the sub-200 nm range fall below the scatter threshold. High-sensitivity flow cytometers or nano-flow cytometry instruments designed for small particle detection are required. Alternatively, you can capture EVs on antibody-coated beads of detectable size before staining. This allows analysis on a standard flow cytometer.
Use a characterised exosome-positive control lysate from a cell line known to express the target marker. Include a negative control such as calnexin, an ER marker absent from true exosomes, to detect cellular contamination. Confirm equal loading using total protein stain, such as Ponceau S, rather than housekeeping genes. Expression levels differ between whole-cell and EV lysates, so housekeeping-gene normalisation is not reliable here.
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