T cells, or T lymphocytes, are leukocytes that are central in human immunity and disease. Types of T lymphocytes include effector T cells, T helper cells, cytotoxic T cells, memory T cells, regulatory T cells, and natural killer T cells. In negative selection of certain T cells, particles (typically magnetic beads) bind to cell surface markers of unwanted cell types. This allows for the separation of unbound and desired cells. When deciding on a T cell negative isolation product, consider the applicable markers, sample volumes and sample formats.