Effects of intermittent administration of IL-15 in immunocompetent macaques. (A) Schedule and dose of administration. Each represents a single dose of IL-15 given every 3 days. (B) Absolute cell numbers of WBCs, lymphocytes, neutrophils (ANCs), as well as T-cell subsets, and NK cells per microliter of peripheral blood of macaques 97067, K00043, 02279, M05118, and T02392. Aliquots of the PBMCs were obtained from each of the macaques before, during, and after the IL-15 treatment, and stained with mAbs to CD3, CD4, CD8, and CD16. The data for CD3⁺CD8⁺, CD3⁺CD4⁺, and CD16⁺ cells are shown as the absolute cell number of each subset per microliter of peripheral blood at the indicated days. (C) Ki-67 expression. The percentage (%) of Ki-67⁺ cells within the CD3⁺CD8⁺, CD3⁺CD4⁺ T-cell, and CD16⁺ NK cell subsets is shown at the indicated days before, during, and after the IL-15 treatment of macaques 97067, K00043, 02279, M05118, and T02392. The vertical bar represents the mean.