Purity > 90% as determined by SDS-PAGE. MW: 19.9kDa. Extracellular Domain: 26-189aa. N-terminal 6xHis-tagged. Bos taurus (Bovine). Identifies cytotoxic/suppressor T-cells that interact with MHC class I bearing targets. CD8 is thought to play a role in the process of T-cell mediated killing. CD8 alpha chains binds to class I MHC molecules alpha-3 domains.