CD86, also known as B-lymphocyte activation antigen B7-2 (formerly referred to as B70), is a member of the cell surface immunoglobulin superfamily. Predominantly existing as a monomer on cell surfaces, B7-2 interacts with two co-stimulatory receptors: CD28 and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), which are expressed on T cells. This interaction initiates signal pathways that regulate T cell activation and tolerance, cytokine production, and the generation of cytotoxic T lymphocytes (CTLs). B7 family members are transmembrane cell surface molecules that play crucial roles in immune activation and the maintenance of immune tolerance.
B7-2 is highly expressed on activated antigen-presenting cells (APCs), such as B cells, dendritic cells, and monocytes, as well as on vascular endothelial cells. B7-2 and its closely related counterpart, B7-1/CD80, exhibit overlapping yet distinct functional characteristics.