Mouse CD8a (Ly-2) MicroBeads have been developed for positive selection or depletion of mouse CD8a+ T cells from single-cell suspensions of lymphoid and non-lymphoid tissues or from peripheral blood. The CD8a antigen is expressed on most thymocytes, almost all cytotoxic T cells, and on subpopulations of dendritic cells. CD8a functions as an accessory molecule in the recognition of MHC class I/peptide complexes by the TCR heterodimer on cytotoxic CD8a+ T cells.