B7-1/CD80 Protein, Rat (HEK293, Fc)

B7-1/CD80, a type I membrane protein, is a member of the B7 family, with an extracellular immunoglobulin constant-like domain and a variable-like domain required for receptor binding. CD80 is also a transmembrane glycoprotein and a member of the Ig superfamily. CD80 can be found on the surface of various immune cells, including B-cells, monocytes, or T-cells, but most typically at antigen-presenting cells (APCs) such as dendritic cells. CD80 has a crucial role in modulating T-cell immune function as a checkpoint protein at the immunological synapse. CD80 binds to CD28 and CTLA-4 with lower affinity and fast binding kinetics, allowing for quick interactions between the communicating cells. These interactions result in an important costimulatory signal in the immunological synapse between antigen-presenting cells, B-cells, dendritic cells and T-cells that result in T and B-cell activation, proliferation and differentiation. Moreover, the interaction of CD80 with CD28, together with TCR and MHC interaction, results in activation of nuclear factor‐κB (NF-ⲕB), mitogen‐activated protein kinase (MAPK), and the calcium‐calcineurin pathway. These changes initiate the production of numerous factors, cytokines, and chemokines by T-cells. CD80, often in tandem with CD86, plays a large and diverse role in regulating both the adaptive and the innate immune system. In addition to interactions with CD28 and CTLA-4, CD80 is also thought to interact with a separate ligand on Natural Killer cells, triggering the Natural Killer cell-mediated cell death of the CD80 carrier^[1][2][3].