CD86 is an 80 kDa member of the immunoglobulin superfamily, also known as B7-2, B70, and Ly-58. It is expressed on activated B cells and T cells, monocytes/macrophages, dendritic cells, and astrocytes. Together with CD80, CD86 serves as a ligand for both CD28 and CD152 (CTLA-4). During immune responses, CD86 is generally expressed earlier than CD80. CD86 has also been shown to participate in immunoglobulin class switching and to trigger NK cell-mediated cytotoxicity. Upon binding to CD28, CD86 transduces co-stimulatory signals that promote T cell activation, proliferation, and cytokine production. Conversely, engagement of CD86 with CD152 (CTLA-4) delivers inhibitory signals to T cells.
