Ultra-LEAF™ Purified anti-human CD80 Antibdy, CD80, W17149G,BioLegend,621804

CD80, also known as B7-1, is a member of the B7 family of proteins. The B7 family of proteins are structurally related, cell membrane-associated molecules that regulate immune responses by delivering costimulatory or coinhibitory signals via their ligands. So far, eight family members have been identified, including B7-1, B7-2, B7-H1, B7-H2, B7-H4, B7-H6, PD-L1, and PD-L2. These proteins are mainly expressed by activated antigen presenting cells (APCs) and when paired with either CD28 or CTLA-4 on a T lymphocyte, they induce an increase or decrease in the downstream signaling activity of the MHC-TCR interaction between APCs and T cells. B7-1 has been shown to bind both CTLA-4 and CD28; however, it has a 20-fold higher affinity to CTLA-4 than to CD28. Despite their structural similarities, the individual contribution of B7-1 and B7-2 to the development of pathogenic T cells in autoimmune diseases and protective T cells in infectious diseases is markedly distinct. Besides regulating T cell immune responses, B7 also plays a role in anti-tumor immunity. This is confirmed by demostrating that cytotoxic T cells were able to eradicate tumor cells transfected with B7-1 and B7-2. After activation, follicular lymphoma was shown to upregulate B7-1 and other costimulatory and adhesion molecules, therefore increasing APC activity and amplifying primed T cell responses. Homozygous null B7-1/B7-2 mice fail to generate antigen specific IgG1 and IgG2a responses, suggesting that B7 proteins are important in Ig immune responses. Mouse and human B7-1 share 44% amino acid identity.