- Other Names
- Cytotoxic T-lymphocyte protein 4, Ctla4, CTLA-4, Cytotoxic T-lymphocyte-associated antigen 4, CD152, Ly-56
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Mouse CTLA-4 was initially identified by differential screening of a murine cytolitic cDNA library. It is a member of the IgG superfamily, and it encodes a 223 amino acid protein and possesses a single extracellular V domain, a transmembrane domain, and a cytoplasmic domain. CTLA-4 is ~30% homologous with CD28, and both bind to the same ligands (B7.1/CD80 and B7.2/CD86) although CTLA-4 binds with higher affinity than CD28. Parallel recognition of a specific MHC-peptide complex by the T-cell receptor and CD80 or CD86 by the costimulatory receptor CD28 results in T cell activation, cytokine production, proliferation, and differentiation. After the T cells' activation process and upregulation of CTLA-4, co-ligation of the TCR to MHC-peptide complex and CTLA-4 to its ligands results in cell cycle arrest and the end to T cell activation. It has been suggested that the negative regulatory mechanism of CTLA-4 is mediated through trans-endocytosis of CD80 and CD86 (capture of ligands from opposing cells). The ligands are removed from the original cell and degraded inside of CTLA-4-expressing cells. As a result, the action of CD28 is impaired. Alternative splice variants of CTLA-4 have been described in mice and humans; these variants skip exon 2 (ligand-binding domain) or exon 3 (transmembrane domain). The ligand independent CTLA-4 is expressed in mice, but not in humans, and the soluble CTLA-4 (sCTLA-4) is expressed in mice and humans. CTLA-4 is constitutively expressed by Tregs, and they are an important source of sCTLA-4. It has been suggested that sCTLA-4 potentiates regulatory T cell function. High levels of sCTLA-4 in Tregs have been associated with type 1 diabetes (T1D) and other autoimmune diseases.Product Details
- Mouse CTLA-4, amino acids Ala37-Phe162 (Accession# AAH42741), with a C-terminal human IgG1 Fc and a 6His-tag was expressed in CHO cells.
- Molecular Mass
- The unlabeled 366 amino acid recombinant protein has a predicted molecular mass of approximately 41 kD. The DTT-reduced and non-reduced glycosylated proteins migrate at approximately 55 kD and 110 kD respectively by SDS-PAGE. The predicted N-terminal amino acid is Ala.
- > 95%, as determined by Coomassie stained SDS-PAGE.
- 0.22 μm filtered protein solution is in PBS, pH 7.2, 5% glycerol.
- Endotoxin Level
- Less than 0.1 EU per μg protein as determined by the LAL method.
- 10-25 µg sizes are bottled at 200 µg/mL. 100 µg size is lot-specific and bottled at the concentration indicated on the vial. (Please contact technical support for concentration, or use our Lookup tool if you have a lot number.)
- Storage & Handling
- Unopened vial can be stored between 2°C and 8°C for one month, at -20°C for six months, or at -70°C for one year. For maximum results, quick spin vial prior to opening. The protein can be aliquoted and stored at -20°C to -70°C. Stock solutions can also be prepared at 50-100 µg/mL in sterile buffer (PBS, HPBS, DPBS, or EBSS) containing carrier protein such as 0.2-1% BSA or HSA and stored in working aliquots at -20°C to -70°C. Avoid repeated freeze/thaw cycles.
- When mouse B7-2/CD86 (Cat. No. 771702) is immobilized at 1.0 µg/mL, mouse CTLA-4-Fc Chimera Biotinylated Protein binds with EC50 of 5 - 20 ng/mL. HRP Avidin (Cat. No. 405103) was used to detect the binding.
- Application Notes
BioLegend carrier-free recombinant proteins provided in liquid format are shipped on blue ice. Our comparison testing data indicates that when handled and stored as recommended, the liquid format has equal or better stability and shelf-life compared to commercially available lyophilized proteins after reconstitution. Our liquid proteins are validated in-house to maintain activity after shipping on blue ice and are backed by our 100% satisfaction guarantee. If you have any concerns, contact us at firstname.lastname@example.org.
Activated T cells, CD4, CD8, and Tregs
- Inhibits T cell activation by reducing IL-2 production and IL-2R expression, also arresting T cells in G1 phase of the cell cycle; protects against the development of autoimmunity.
- Antigen presenting cells, B cells
- Ligand Receptor
- CD80 (B7.1), CD86 (B7.2)
- Measured by its ability to bind mouse CD86
- Cell Type
- T cells, Tregs, B cells
- Biology Area
- Molecular Family
- Soluble Receptors, CD Molecules, Immune Checkpoint Receptors
- Gene ID
- 12477 View all products for this Gene ID
- View information about CTLA-4 on UniProt.org
- Does specific activity of a recombinant protein vary between lots?
Specific activity will vary for each lot and for the type of experiment that is done to validate it, but all passed lots will have activity within the established ED50 range for the product and we guarantee that our products will have lot-to-lot consistency. Please conduct an experiment-specific validation to find the optimal ED50 for your system.
- Have your recombinants been tested for stability?
Our testing shows that the recombinant proteins are able to withstand room temperature for a week without losing activity. In addition the recombinant proteins were also found to withstand four cycles of freeze and thaw without losing activity.
- How do you convert activity as an ED50 in ng/ml to a specific activity in Units/mg?
- Use formula Specific activity (Units/mg) = 10e6/ ED50 (ng/mL)
- How does the activity of your recombinant proteins compare to competitors?
We quality control each and every lot of recombinant protein. Not only do we check its bioactivity, but we also compare it against other commercially available recombinant proteins. We make sure each recombinant protein’s activity is at least as good as or better than the competition’s. In order to provide you with the best possible product, we ensure that our testing process is rigorous and thorough. If you’re curious and eager to make the switch to BioLegend recombinants, contact your sales representative today!
- What is the specific activity or ED50 of my recombinant protein?
The specific activity range of the protein is indicated on the product datasheets. Because the exact activity values on a per unit basis can largely fluctuate depending on a number of factors, including the nature of the assay, cell density, age of cells/passage number, culture media used, and end user technique, the specific activity is best defined as a range and we guarantee the specific activity of all our lots will be within the range indicated on the datasheet. Please note this only applies to recombinants labeled for use in bioassays. ELISA standard recombinant proteins are not recommended for bioassay usage as they are not tested for these applications.