Analysis of lymphocyte subsets after daily administration of IL-15. (A-B) Samples of PBMCs were obtained from macaque 02269 (A) or macaque 05078 (B) before, during, and after the IL-15 treatment. Aliquots of PBMCs were stained with mAbs binding to CD3, CD4, CD8, or CD16, and examined by flow cytometry. The data for CD3⁺CD4⁺ (▵), CD3⁺CD8⁺ (●), and CD16⁺ (♦) are shown as the absolute cell number of each subset per microliter of blood at the indicated days. (C) Representative sample of PBMCs obtained from macaque 05078 at the end of the IL-15 treatment. Aliquots of PBMCs were stained with mAbs binding to CD3, CD4, CD8, and a TCRγδ-specific mAb, and examined by flow cytometry. (Left panel) Cells are gated on CD3⁺ T cells. The values indicate the proportion of each of the T-cell subsets (in percentage). (Right panel) TCRγδ T cells within the PBMC population. (D) The data for CD3⁺CD4⁻CD8⁻ cells (◇) are shown as the absolute cell number of each subset per microliter of blood at the indicated days. (E-F) Expression of Ki-67. Aliquots of PBMCs from macaque 02269 (E) or macaque 05078 (F) were obtained before, during, or after the IL-15 treatment and were examined for intracellular expression of Ki-67 within the CD3⁺CD4⁺, CD3⁺CD8⁺, or CD3⁺CD4⁻CD8⁻ T-cell compartment, and within the CD16⁺ NK cell subset. The fraction of Ki-67–expressing cells in percentage (%) in each of the subsets on the indicated days before, during, and after the IL-15 treatment is shown. indicates the duration of the IL-15 administration.