Examples of using monoclonal antibodies that recognize exosome markers
User report
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Yusuke Yoshioka National Cancer Center Research Institute |
Products
- Anti CD9 for Exosome Isolation, Human (Mouse) Unlabeled, 12A12 (Product number: SHI-EXO-M01)
- Anti CD63 for Exosome Isolation, Human (Mouse) Unlabeled, 8A12 (Product number: SHI-EXO-M02)
- Anti CD81 for Exosome Isolation, Human (Mouse) Unlabeled, 12C4 (Product number: SHI-EXO-M03)
Manufacturer: Cosmo Bio Co., Ltd.
■ Monoclonal antibody for exosome isolation Anti CD9, CD63, CD81
This product is an antibody that specifically recognizes CD9, CD63, and CD81 known as exosome markers, and is an antibody that can isolate exosomes from serum and culture supernatant using immunoprecipitation method.
- Recognize exosome membrane proteins CD9, CD63, CD81 with high specificity
- Exosome surface antigen protein, endogenous RNA (miRNA), useful for protein analysis
Experiment content
In 1975, George Koehler and Cesar Milstein invented monoclonal antibody production technology, and in 1984 won the Nobel Prize in Physiology or Medicine. However, although they only recognize a single epitope, the existence of monoclonal antibodies is revolutionizing the current field of diagnostics and medicines such as molecular target therapeutics such as antibody drugs. His contributions are not only limited to the medical field, but also to us life science researchers. Monoclonal antibodies are used for a variety of purposes, including detection of specific proteins, intracellular localization, protein-protein interactions, and affinity purification. can be "Good" in this case varies depending on the application and circumstances, but generally it means that the target analytical application recognizes and binds strongly to a single molecule.
It is also important to obtain "good antibodies" in exosome research. Exosomes are around 100 nm in size, and various proteins are present inside and on the lipid bilayer membrane. Currently, methods for collecting exosomes from body fluids and culture supernatants and confirming their existence include detection of exosome markers by immunoelectron microscopy and immunoblotting. Both of these methods require antibodies. In addition, the ELISA method is sometimes used as a method for quantifying exosome proteins, which also requires antibodies. Furthermore, antibodies are also used in methods for recovering only specific exosome populations by performing affinity purification using immunoprecipitation or columns against exosome membrane proteins using antibodies.
In this way, in exosome research, antibodies are used in a wide variety of applications, but the question is what kind of antigen-recognizing antibodies are useful in exosome research. Since exosomes are complexes composed of various molecules, not all exosomes secreted from the same cell contain the same molecules. However, proteins called exosome markers are believed to be contained in most exosomes. Although the exact ratio is unknown, the existence of exosome markers can be confirmed by collecting what is called exosomes and examining the presence or absence of exosome markers. Currently, tetraspanins such as CD9, CD63, and CD81 are mainly used as exosome markers (Reference 1), and antibodies against these antigens will inevitably become more frequently used and necessary in exosome research.
When I started exosome research, I started by building an exosome detection system, but I had a hard time finding a monoclonal antibody that recognizes exosome markers in this detection system. I've tried several clones, but the results were disappointing. I managed to obtain an exosome marker antibody that could be used for Western blotting, but it did not suit my intended use. At that time, I encountered anti-CD9 antibody 12A12 and anti-CD63 antibody 8A12, and the exosome detection system worked well (Fig. 1) (see Reference 2). This antibody could also be used for Western blotting (Fig. 2) and immunoelectron microscopy for exosome detection. Since it does not recognize non-human animal species such as mouse CD9 and mouse CD63, it cannot be used in mouse systems, but it can distinguish human and mouse exosomes in experiments such as human cancer cell transplantation systems into mice. Therefore, it may come in handy in return.
Although it is not limited to exosome markers, we often hear that the desired experimental system cannot be set up because good antibodies are not available. If you are having trouble detecting human exosomes, you may be able to use the anti-CD9 antibody 12A12, the anti-CD63 antibody 8A12, and the anti-CD81 antibody 12C4 to proceed successfully.
- Yoshioka Y, et al.: J Extracell Vesicles , 2 : 20424, 2013
- Yoshioka Y, et al.: Nat Commun , 5 : 3591, 2014