Cluster of differentiation 80 (CD80) interacts with its ligand, co-stimulator ligand CD28 or with cytotoxic T-lymphocyte protein 4 (CTLA-4) and facilitates the regulation of CD4+ and CD8+ T cell activity. Elevated urinary CD80 excretion leads to Fabry disease. CD80, which is expressed on surface of dendritic cells acts as a key co-stimulatory molecule and induces second signal for the proper stimulation of cancer antigen-specific naive T cells.
