Cytotoxic T-lymphocyte antigen 4 (CTLA4), aslo known as CD152, is a single pass type I transmembrane glycoprotein of the Ig superfamily. It is composed of an IgV-type extracellular domain, a transmembrane domain, and a cytoplasmic tail.  CTLA4 is the founding member of the CD28/CTLA-4 family. Members of the CD28/CTLA-4 family either promote T cell activation (CD28 and ICOS) or inhibit T cell activation (CTLA4 and PD­1).  Both CTLA-4 and CD28 bind to the same B7 family ligands, CD80/B7-1 and CD86/B7-2.  CTLA-4 binds to B7-1 and B7-2 with a 20-100 fold higher affinity than CD28.  The CTLA4 gene is widely expressed with highest levels in lymphoid tissues.  It is detected in activated T-cells where expression levels are 30- to 50-fold less than CD28 on the cell surface following activation. Mutations in CTLA4 gene is associated with insulin-dependent diabetes mellitus, Graves disease, Hashimoto thyroiditis, celiac disease, systemic lupus erythematosus, thyroid-associated orbitopathy, and other autoimmune diseases.  Alternate transcriptional splice variants, encoding different isoforms of CTLA4, have been characterized. The membrane-bound isoform functions as a homodimer interconnected by a disulfide bond, while the soluble isoform functions as a monomer. The engineered CTLA4-Fc fusion proteins inhibit T-cell-dependent immune responses and are used as immunosuppressive agents by acting as a competitive inhibitor of CD28. Blockade of CTLA4 inhibitory activity with monoclonal antibodies enhances antitumor immunity and has been proven to be an effective approach for cancer immunotherapy. 

Cytotoxic T-lymphocyte antigen 4 (CTLA4), aslo known as CD152, is a single pass type I transmembrane glycoprotein of the Ig superfamily. It is composed of an IgV-type extracellular domain, a transmembrane domain, and a cytoplasmic tail.  CTLA4 is the founding member of the CD28/CTLA-4 family. Members of the CD28/CTLA-4 family either promote T cell activation (CD28 and ICOS) or inhibit T cell activation (CTLA4 and PD­1).  Both CTLA-4 and CD28 bind to the same B7 family ligands, CD80/B7-1 and CD86/B7-2.  CTLA-4 binds to B7-1 and B7-2 with a 20-100 fold higher affinity than CD28.  The CTLA4 gene is widely expressed with highest levels in lymphoid tissues.  It is detected in activated T-cells where expression levels are 30- to 50-fold less than CD28 on the cell surface following activation. Mutations in CTLA4 gene is associated with insulin-dependent diabetes mellitus, Graves disease, Hashimoto thyroiditis, celiac disease, systemic lupus erythematosus, thyroid-associated orbitopathy, and other autoimmune diseases.  Alternate transcriptional splice variants, encoding different isoforms of CTLA4, have been characterized. The membrane-bound isoform functions as a homodimer interconnected by a disulfide bond, while the soluble isoform functions as a monomer. The engineered CTLA4-Fc fusion proteins inhibit T-cell-dependent immune responses and are used as immunosuppressive agents by acting as a competitive inhibitor of CD28. Blockade of CTLA4 inhibitory activity with monoclonal antibodies enhances antitumor immunity and has been proven to be an effective approach for cancer immunotherapy. 

 

Product Details

 

Gene Symbol: CTLA4; CD152; CD; GSE; GRD4; CTLA-4; IDDM12; CELIAC3

 

NCBI Gene ID: 14931

 

Uniprot Entry: P16410

 

Construct Details: The recombinant human CTLA4 ECD is expressed as a 138-amino acid protein consisting of Lys36 - Asp161 region of CTLA4 (UniProt accession #Q16410) and a C-terminal His-tag. It contains 2 potential N-linked glycosylation sites.

 

Source:  Human cells stably expressing CTLA4 ECD and growing in chemical-defined media with no animal components or antibiotics

 

Deduced Amino Acid Sequence:

KAMHVAQPAVVLASSRGIASFVCEYASPGKATEVRVTVLRQADSQVTEVCAATYMMGNELTFLDDSICTGTSSGNQ

VNLTIQGLRAMDTGLYICKVELMYPPPYYLGIGNGTQIYVIDPEPCPDSDGSTGHHHHHHHH

M.W.: Calculated molecular mass 14.9 kDa; estimated by SDS-PAGE under reducing condition ~25 kDa probably due to glycosylation

 

Calculated PI: 5.76

 

Calculated Extinction Coefficients (M-1 cm-1, at 280nm):  10,680

 

Purity: >95% judged by SDS-PAGE under reducing condition (see the gel image above)

 

Formulation: Supplied at 0.5 mg/ml in sterile PBSpH7.4 (carrier and preservative free). The purified recombinant protein was labeled with Biotin (3-5 Biotin per molecule) using the standard procedure.

 

Endotoxin Level: <0.1 EU per 1 μg of purified recombinant protein determined by the LAL method

 

Biological Activity: Binds to human B7 family ligands, CD80/B7-1 (SKU#: FCL0716 and FCL0723) and CD86/B7-2 (SKU#: FCL0718 and FCL0725), and anti-CTLA4 monoclonal antibody (SKU#: MAB1718) with high affinity K_D < 1 nM as measured by ELISA (see the attached technical data)

 

 

FOR RESEARCH USE ONLY. NOT FOR DIAGNOSTIC OR THERAPEUTIC USE IN HUMAN.

Restriction: This product is not transferable or re-sellable.  Customer obtain no right to transfer, assign, or sublicense its use rights, or to transfer, resell, package, or otherwise distribute the product, or to use the product for the benefit of any third party or for any commercial purpose.  Customer may only use the product in compliance with applicable local, state and federal laws, regulations and rules.  Customer may not directly or indirectly use the product or allow the transfer, transmission, export or re-export of all or any part of the product in violation of any export control law or regulation of the united states or any other relevant jurisdiction.  Your use of this product constitutes acceptance of the terms of this limited use agreement.  Please refer to our “terms & conditions” for details.  If you are not willing to accept the limitation of this agreement, G&P Biosciences will accept return of the product for a full/partial refund.

 

 

Technical Data

 

Recombinant CTLA4 ECD protein (SKU#FCL0720) was immobilized at 100 ng/well on a 96-well ELISA plate and incubated with serially diluted anti-CTLA4 human IgG1 monoclonal antibody (SKU#MAB1718). Anti-PD-1 (SKU#MAB1732) human IgG1 monoclonal antibody was used as a control to demonstrate the specificity of CTLA4 binding under the experimental conditions.  The bound antibodies were detected by goat anti-human IgG HRP conjugated secondary antibody.  The ELISA binding curve was fit and K_D was calculated for anti-CTLA4:CTLA4 binding (affinity/avidity) to be 16 pM. 

 

 

 

FOR RESEARCH USE ONLY. NOT FOR DIAGNOSTIC OR THERAPEUTIC USE IN HUMAN.

 

Storage

 

The product is shipped at 4°C. Upon receipt, centrifuge the product briefly before opening the vial. It is recommended to store small aliquots at the temperature below –20°C for long-term storage and the product is stable for at least 3 months. The undiluted protein can be stored at 4°C for no more than 2 weeks.

 

 

Use a manual defrost freezer and avoid repeated freeze-thaw cycles.

 

 

 

FOR RESEARCH USE ONLY. NOT FOR DIAGNOSTIC OR THERAPEUTIC USE IN HUMAN.

 

References

 

1. Eur. J. Immunol. 18:1901-1905 (1988)

2. J. Exp. Med. 174:561-569 (1991)

3. Annu. Rev. Immunol. 24:65-97 (2006)

4. Immunol. Rev. 229:307-321 (2009) 

 

 

 

Documentation

 

Product datasheet (pdf) can be downloaded here: FCL0720-PDS.pdf

 

 

 

Additional supporting documents, including COA and MSDS are available upon request.

 

 

 

FOR RESEARCH USE ONLY. NOT FOR DIAGNOSTIC OR THERAPEUTIC USE IN HUMAN.

Restriction: This product is not transferable or re-sellable.  Customer obtain no right to transfer, assign, or sublicense its use rights, or to transfer, resell, package, or otherwise distribute the product, or to use the product for the benefit of any third party or for any commercial purpose.  Customer may only use the product in compliance with applicable local, state and federal laws, regulations and rules.  Customer may not directly or indirectly use the product or allow the transfer, transmission, export or re-export of all or any part of the product in violation of any export control law or regulation of the united states or any other relevant jurisdiction.  Your use of this product constitutes acceptance of the terms of this limited use agreement.  Please refer to our “terms & conditions” for details.  If you are not willing to accept the limitation of this agreement, G&P Biosciences will accept return of the product for a full/partial refund.