Human CTLA-4, His Tag, low endotoxin (CT4-H522a) is expressed from human 293 cells (HEK293). It contains AA Ala 37 - Phe 162 (Accession # NP_005205.2).
Predicted N-terminus: Ala 37
This protein carries a polyhistidine tag at the C-terminus.
The protein has a calculated MW of 15.4 kDa. The protein migrates as 25-30 kDa under reducing (R) condition (SDS-PAGE) due to different extent glycosylation.
Less than 0.01 EU per μg by the LAL method.
>95% as determined by SDS-PAGE.
Lyophilized from 0.22 μm filtered solution in PBS, pH7.4. Normally trehalose is added as protectant before lyophilization.
Contact us for customized product form or formulation.
Please see Certificate of Analysis for specific instructions.
For best performance, we strongly recommend you to follow the reconstitution protocol provided in the CoA.
For long term storage, the product should be stored at lyophilized state at -20°C or lower.
Please avoid repeated freeze-thaw cycles.
This product is stable after storage at:
- -20°C to -70°C for 12 months in lyophilized state;
- -70°C for 3 months under sterile conditions after reconstitution.
Human CTLA-4, His Tag, low endotoxin on SDS-PAGE under reducing (R) condition. The gel was stained overnight with Coomassie Blue. The purity of the protein is greater than 95%.
Immobilized Human B7-1, Fc Tag (Cat. No. B71-H5259) at 2 μg/mL (100 μL/well) can bind Human CTLA-4, His Tag, low endotoxin (Cat. No. CT4-H522a) with a linear range of 0.2-3 ng/mL (QC tested).
Immobilized Human B7-2, Fc Tag (Cat. No. CD6-H5257) at 2 μg/mL (100 μL/well) can bind Human CTLA-4, His Tag, low endotoxin (Cat. No. CT4-H522a) with a linear range of 1-6 ng/mL (Routinely tested).
CTLA-4 (Cytotoxic T-Lymphocyte Antigen 4) is also known as CD152 (Cluster of differentiation 152), is a protein receptor that downregulates the immune system. CTLA4 is a member of the immunoglobulin superfamily, which is expressed on the surface of Helper T cells and transmits an inhibitory signal to T cells. The protein contains an extracellular V domain, a transmembrane domain, and a cytoplasmic tail. Alternate splice variants, encoding different isoforms. CTLA4 is similar to the T-cell co-stimulatory protein, CD28, and both molecules bind to CD80 and CD86, also called B7-1 and B7-2 respectively, on antigen-presenting cells. CTLA4 transmits an inhibitory signal to T cells, whereas CD28 transmits a stimulatory signal. Intracellular CTLA4 is also found in regulatory T cells and may be important to their function. T cell activation through the T cell receptor and CD28 leads to increased expression of CTLA-4, an inhibitory receptor for B7 molecules. Fusion proteins of CTLA4 and antibodies (CTLA4-Ig) have been used in clinical trials for rheumatoid arthritis.