Clone OKT8, a mouse monoclonal antibody, binds with a 32-34 kDa type I transmembrane glycoprotein known as CD8 a member of the immunoglobulin superfamily. OKT8 binds to CD8?, which forms either a homodimer or a heterodimer with CD8?. It is expressed on the surface of cytotoxic T cells, NK cells, cortical thymocytes, and on some dendritic cells. CD8 functions as a co-receptor for T-cell receptors and specifically binds to class I MHC for antigen recognition and T-cell activation.