Serial dilutions of Ipilimumab were added into Human CTLA-4, Fc Tag (Cat. No. CT4-H5255): Biotinylated Human B7-1, Fc,Avitag (Cat. No. B71-H82F2) binding reactions. The half maximal inhibitory concentration (IC50) is 0.8260 μg/mL (Routinely tested).
Flow Cytometry assay shows that Biotinylated Human B7-1, Fc,Avitag (Cat. No. B71-H82F2) can bind to 293 cell overexpressing human CTLA-4. The concentration of Human B7-1 is 0.3 μg/mL (Routinely tested).
FACS analysis shows that the binding of Biotinylated Human B7-1, Fc,Avitag (Cat. No. B71-H82F2) to 293 overexpressing CTLA-4 was inhibited by increasing concentration of neutralizing Anti-Human CTLA-4 antibody. The concentration of B7-1 used is 0.3 μg/mL. The IC50 is 3.025 μg/mL (Routinely tested).
B7-1 and B7-2, together with their receptors CD28 and CTLA4, constitute one of the dominant co-stimulatory pathways that regulate T and Bcell responses. Although both CTLA4 and CD28 can bind to the same ligands, CTLA4 binds to B71 and B72 with a 20 100 fold higher affinity than CD28 and is involved in the downregulation of the immune response.
B-lymphocyte activation antigen B7-1 (referred to as B7) also known as cluster of Differentiation 80 (CD80), is a member of cell surface immunoglobulin superfamily and is expressed on activated B cells, activated T cells, macrophages and dendritic cells. It is the ligand for two different proteins on the T cell surface: CD28 (for autoregulation and intercellular association) and CTLA-4 (for attenuation of regulation and cellular disassociation). CD80 works in tandem with CD86 to prime T cells. CD80 plays a role in induction of innate immune responses by activating NF-κB-signaling pathway in macrophages. CD80 is thus regarded as promising therapeutic targets for autoimmune diseases and various carcinomas.