Isolation of T-Cell Subsets by Magnetic Cell Sorting (MACS)

T cells are defined by the expression of CD3 molecules on the cell surface in association with the T-cell receptor (TCR) to form the TCR/CD3 complex. Within the CD3⁺ cell population there are two main subsets identified by the expression of CD4 (CD4⁺ T cells) and CD8 (CD8⁺ T cells) cell surface molecules. In addition, there is a small percentage of CD3⁺ T cells which are either negative for both CD4 and CD8 (CD4⁻ CD8⁻ ) or are double positive (CD4⁺ CD8⁺ ).