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 antibody is expressed as the combination of a heavy chain (HC) containing VH from anti-CTLA4 mAb and CH region of rabbit IgG and a light chain (LC) encoding VL from anti-CTLA4 mAb and CL.  Exists as a disulfide linked dimer of the HC and LC hetero-dimer under non-reducing condition.

 

Source: Mammalian cells stably expressing anti-CTLA4 HC and LC and growing in chemical-defined media with no animal component or antibiotics.

 

M.W.:  Calculated molecular mass (kDa): 147 (49 kDa for a single HC, 24 kDa for a single LC); Estimated by SDS-PAGE under non-reducing condition(kDa): 150.

 

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

 

Formulation: Supplied at 0.5 mg/ml in sterile PBS pH7.4 without any carrier protein or preservative (the concentration was determined by UV absorption with an A280nm of 1.0 for 0.73 mg/ml of IgG and verified by SDS-PAGE and Coomassie blue staining).

 

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

 

Biological Activity: Binds to CTLA4 extracellular domain (SKU#: FCL0720 and FCL0727) with high affinity (K_D < 1 nM as determined by ELISA - see the attached technical data).  Recognizes cell surface CTLA4 by flow cytometry, IHC staining and fluorescent microscopy.  Blocks CTLA4 binding to its ligands and neutralizes its inhibitory signaling activities.  Enhances anti-tumor immunity in vivo. Binds CTLA4 with the same specificity as anti-CTLA4 monoclonal antibodies, human IgG1 (SKU#MAB1718) and mouse IgG2a (SKU#MAB0720).

 

  

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 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: MAB0727-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.