Human Cytotoxic T-Lymphocyte Associated Antigen-4 (Recombinant)

Recombinant Human Cytotoxic T-Lymphocyte Associated Antigen-4/Fc Chimera (CTLA-4)

Source: Sf9 cells

Background: CTLA-4 is expressed in low copy number by T-cells only after activation, but it binds CD28-ligand with approximately 20-fold higher affinity than CD28. A soluble form of the extracellular domain of CTLA-4 has been shown to bind CD28-ligand with high avidity and to suppress T-cell-dependent antibody responses in vivo. Large doses of this soluble protein also suppress responses to a second immunization.

Description: Recombinant Human CTLA-4 produced in insect cells is a homodimeric, glycosylated, polypeptide chain containing a total molecular mass of 80 kDa. Each subunit (40kDa) is fused to a polypeptide linker to the Fc portion of Human IgG1. CTLA-4 is expressed in low copy number by T-cells only after activation, but it binds CD28-ligand with approximately 20-fold higher affinity than CD28. A soluble form of the extracellular domain of CTLA-4 has been shown to bind CD28-ligand with high avidity and to suppress T-cell-dependent antibody responses in vivo. Large doses of this soluble protein also suppress responses to a second immunization. Recombinant Human CTLA-4 is purified by proprietary chromatographic techniques.

Physical Appearance: Sterile Filtered White lyophilized (freeze-dried) powder.

Formulation: Recombinant CTLA-4 was lyophilized with no additives.

Solubility: It is recommended to reconstitute the lyophilized CTLA4 in sterile 18MO-cm H2O not less than 100 g/ml, which can then be further diluted to other aqueous solutions.

Stability: Lyophilized CTLA4 although stable at room temperature for 3 weeks, should be stored desiccated below -180C. Upon reconstitution CTLA-4 should be stored at 40C between 2-7 days and for future use below -180C. For long term storage it is recommended to add a carrier protein (0.1% HSA or BSA). Please avoid freeze-thaw cycles.

Purity: Greater than 95.0% as determined by: (a) Analysis by RP-HPLC. (b) Anion-exchange FPLC. (c) Analysis by reducing and non-reducing SDS-PAGE Silver Stained gel.

Amino acid sequence: The sequence of the amino acids was determined and was found to be: Lys-Ala-Met-His-Val.

Dimers and aggregates: Less than 1% as determined by silver-stained SDS-PAGE gel analysis.

Biological Activity: ProSpec's Recombinant CTLA-4 is fully biologically active when compared to standards.

Endotoxin: Less than 0.1 ng/ g (IEU/ g) of CTLA-4.

Protein content: Protein quantitation was carried out by two independent methods: 1. UV spectroscopy at 280. 2. Analysis by RP-HPLC, using a standard solution of Human CTLA-4 as a Reference Standard.

Usage: BioWORLD's products are furnished for LABORATORY RESEARCH USE ONLY. The product may not be used as drugs, agricultural or pesticidal products, food additives or household chemicals.