FIG. 4.

Tim-3^positive CD8⁺ T-cell populations contain more central and less effector memory cells than their Tim-3^negative counterparts. (A) Naïve, central memory (CM), and effector memory (EM) T-cell subsets can be defined by the pattern of expression of CD45RA and CCR7 as shown. In the CD8⁺ T-cell population, cells positive for CD4RA and not expressing CCR7 are thought to be terminally differentiated effector memory (TDEM) cells derived from the effector memory cell population which re-express this antigen. (B) CD4⁺ and CD8⁺ T cells were subdivided on the basis of positivity and negativity for Tim-3 expression. Tim-3-positive and Tim-3-negative CD4⁺/CD8⁺ T cells were analyzed for the expression of CD45RA and CCR7 to determine the relative maturation stages of these populations. A higher proportion of the Tim-3-positive CD8⁺ T cells demonstrated a central memory (CM) phenotype, while fewer demonstrated an effector memory phenotype than their Tim-3-negative counterparts. No difference was demonstrated for the TDEM population (data not shown). Each symbol represents an individual patient, and the horizontal lines demonstrate the mean. No differences in maturation phenotype were observed for the CD4⁺ T-cell subsets. Data points are shown for central and effector memory populations only.