CD8 MicroBeads
Description CD8 MicroBeads were developed for the isolation of CD8+ cells. The CD8 antigen forms a complex together with the T cell receptor and acts as an accessory molecule in the recognition of MHC class I/peptide complexes by the TCR heterodimer on CD8+ cytotoxic T cells. The CD8 molecule consists of either an α/β heterodimer or an α/α homodimer. It is expressed strongly on cytotoxic T cells and dimly on a subset of NK cells. CD8 is found on most thymocytes and on about one third of all peripheral blood T cells. CD8+ cytotoxic T cells play an important role in the killing of virus-infected cells and tumor cells. Applications CD8 MicroBeads are commonly used for positive selection or depletion of cytotoxic T cells from different cell sources, as reported in many different publications. The most commonly used cell sources are peripheral blood and cord blood. In addition, cytotoxic T cells have also been isolated from lymph nodes, thymus, skin biopsies1, and spleen. Isolation or depletion of CD8+ cytotoxic T cells is performed in many different research fields such as infectious diseases, autoimmune diseases, allergy, and asthma, as well as tumor immunology. Cytotoxic T cells isolated by MACS® Technology remain viable and functional. Therefore, they can be used for further functional studies, such as proliferation assays2,9 and cytotoxicity assays2,3, but also for the analysis of in vitro cytokine production4. CD8 MicroBeads have also been used for the depletion of CD8+ T cells from human PBMCs for immune reconstitution experiments in SCID mice.5 In combination with CD4 MultiSort MicroBeads, CD8 MicroBeads have been used for the isolation of CD4+CD8+ double-positive thymocytes.8 Other examples include various studies on viral infections, e.g., in vitro infections of CD8+ cells with HIV6, or monitoring of immune abnormalities in children of HIV-infected mothers7. Columns For positive selection: MS, LS, XS, or autoMACS™ Columns; for depletion: LD, CS, D, or autoMACS Columns.		Figure 1 Separation of CD8+ cells from PBMCs using CD8 MicroBeads, an LS Column, and a MidiMACS™ Separator. PBMCs before separation CD8- cells CD8+ cells Figure 2 Scanning electron micrograph of CD8+ T cells isolated using CD8 MicroBeads (courtesy of Prof. Peter Groscurth, Institute of Anatomy, University of Zürich, Switzerland).