CD8 is a cell surface glycoprotein found on most cytotoxic T lymphocytes and is used as a marker for these cells. It acts as a coreceptor for T cell receptor and functions to recognize MHC –I antigens. 10%-30% human lymphocytes are CD8 positive. Human CD8 Magnetic Beads Kit is used for isolation or depletion of human CD8 T lymphocytes from PBMC, whole blood, or other sample types. Following incubation with biotinylated human CD8 antibody and streptavidin conjugated magnetic beads, the cell sample is placed on a magnet. CD8+ cells remain attached to magnetic beads after separation and can be used for downstream applications, such as cell expansion, but are not suitable for flow cytometry analysis. CD8- cells remain in the supernatant and can be used for further applications.