Clinical pathology and peripheral blood flow cytometry from cynomolgus monkeys receiving CLL1/CD3L TDB. Target cell depletion of neutrophils (A) and monocytes (B) is similar between both dose groups, with nadirs between day 4 and 8 and 2 and 8 post dose, respectively. Rebound neutrophilia between days 10 and 15 is marked and greater in the 0.2 mg/kg dose group. Note, the mild decrease in neutrophil count on day 2 in the vehicle group is likely secondary to repeat blood sampling. Reduction of lymphocytes (C) occurred in 2 waves (days 2-8) concurrent to target cell depletion, elevation of acute phase proteins such as C-reactive protein (D), and increased activation of CD8⁺ cytotoxic T cells as measured by CD69 (E) and CD25 (F) expression. The immediate increase in percentage of CD69⁺ CD8⁺ T cells was greater (peak 71.3%-80.7% vs 25.2%-57.0%), and the percentage of CD25⁺ T cells was elevated for longer (return to baseline D15-D22 vs D8-D15) in the 0.5 mg/kg group.