FIGURE 2.

Representation and definition of CD8⁺ T cell memory subpopulations. Expression of differentiation markers including CD45RO, CD27, CCR7, CD57, PD-1, and CD127 were analyzed on total CD8⁺ T cells at 6–9 mo postinfection using flow cytometry. Using these markers, we were able to discriminate six different subsets: central memory (T_CM, CD45RO⁺CD27⁺CCR7⁺), transitional memory (T_TM, CD45RO⁺ CD27⁺CCR7⁻), effector memory (T_EM, CD45RO⁺CD27⁻CCR7⁻), naive (T_Naive, CD45RO⁻CD27⁺CCR7⁺), intermediate (T_Int, CD45RO⁻CD27^dim CCR7⁻), and effector (T_Eff, CD45RO⁻CD27⁻CCR7⁻). A, Representative flow plots of CD45RO, CD27, and CCR7 profiles of total CD8⁺ T cells and the gating strategy for detection of T_CM, T_EM, T_TM, T_Naive, T_Int, and T_Eff. B, Comparison of memory subset distribution in HIV-uninfected (n = 15) and HIV-infected individuals (n = 16). C, Percentage expression of CD127, CD57, and PD-1 in T_CM, T_EM, T_TM, T_Naive, T_Int, and T_Eff. Each datum point represents an HIV-positive individual. Proportional differences in expression of CD27, CCR7, CD45RO, CD127, CD57, and PD-1 are shown as heat maps, based on the mean percentage expression within the different CD8⁺ T cell subpopulations. D, Representative flow plots for CD57/CD127 and CD127/PD-1 staining in T_Naive, T_CM, T_EM, T_TM, T_Int, and T_Eff CD8⁺ T cells subsets.