Analysis of CD8⁺ T_N, T_CM, and T_EM subsets during intermittent IL-15 administration. (A) Samples of PBMCs were obtained from macaques 97067, K00043, 02279, M05118, and T02392 before, during, and after the treatment with IL-15. Cells were stained with mAbs binding to CD3, CD8, or CD95, and CCR7 and analyzed by flow cytometry to distinguish T_N (CD95^lowCCR7⁺), T_CM (CD95⁺CCR7⁺), and T_EM (CD95⁺CCR7⁻) subsets. The fold increase of each subset at the indicated time of treatment is shown. The vertical bar represents the mean. indicates the duration of the IL-15 treatment. The last posttreatment PBMC sample from K00043 was obtained on day 283. (B-C) Expression of Ki-67 by CD8⁺ T-cell subsets. (B) Representative data of macaque 02279. Gating of CD8⁺ T_N, T_CM, and T_EM subsets stained for Ki-67 expression. PBMCs were stained with mAb specific for CD3, CD8, CD95, and CCR7, permeabilized, and stained with an antibody that binds to Ki-67, and analyzed by flow cytometry. Cells are gated on CD3⁺CD8⁺ T cells. The inset value in the upper right quadrant indicates the proportion of Ki-67⁺ T cells (in percentage). (C) The percentage (%) of Ki-67⁺ T cells within the CD8⁺ T_N, T_CM, and T_EM subsets is shown at the indicated time of IL-15 treatment of macaques 97067, K00043, 02279, M05118, and T02392. The vertical bar represents the mean. indicates the duration of the IL-15 treatment.