Chemotaxis of CD8 T-cell subsets. Chemotaxis of CD8 T-cell subsets in response to IL-8 (A) and MDC (B). Migration of CM, EM, and EMRA CD8 T cells is shown relative to background migration of naive CD8 T cells. Migration of naive CD8 T cells (CCR7⁺CD45RA^high) was not affected by IL-8 or MDC. Subset migration relative to migration of naive CD8 T cells in the absence of chemokine is defined as a chemotactic index of 1. Note that the selective migration of EMRA is greater than that of EM CD8 T cells in response to IL-8, versus the selective migration of CM that is greater than that of EM CD8 T cells in response to MDC. Representative data from 3 independent experiments are shown.