CD4 is a coreceptor of T cell receptor in T lymphocytes to recognize antigens displayed by an antigen presenting cell in the context of class II MHC molecules. It is observed that 25%-65% human lymphocytes are CD4 positive. Human CD4 Magnetic Beads Kit is used for isolation or depletion of human CD4 T lymphocytes from PBMC, whole blood, or other sample types. Following incubation with biotinylated human CD4 antibody and Streptavidin magnetic beads, the cell sample is placed on a magnet. CD4+ cells remain attached to magnetic beads after separation and can be used for downstream applications, such as cell expansion, but not suitable for flow cytometry. CD4- cells remain in supernatant and can also be used for further application.