BsAb-2 induces dose-dependent lymphocyte proliferation in cynomolgus monkeys. Healthy cynomolgus monkeys (n = 2 per treatment group [1 male + 1 female]) were treated once with 0.03, 0.1, or 0.3 mg/kg body weight of BsAb-2 by intravenous injection. Peripheral blood was collected at 10 time points and cellular compartment was analyzed by flow cytometry. (A to E) Percentages of Ki67-expressing CD8+ T-cells (A), CD3-CD159a+ NK-cells (B), CD4+ T-cells (C), CD4+CD25+FoxP3+ Tregs (D), and CD3-CD20+ B-cells (E). (F to J) Absolute cell numbers of CD8+ T-cells (F), CD3-CD159a+ NK-cells (G), CD4+ T-cells (H), CD4+CD25+FoxP3+ Tregs (I), and CD3-CD20+ B-cells (J). Cell numbers determined using BD TruCount beads. (K) Ratio of CD8+ T-cells to CD4+ T-cells in cynomolgus peripheral blood.Data shown is the mean of the two subjects.