Blood neutrophil half-life in MKO mice is normal. BrdU (2 mg) was administered to control (CTL) or MKO mice by a single intraperitoneal injection. Peripheral blood was obtained at the indicated time points and the number of BrdU⁺ Gr-1^bright cells determined by flow cytometry. (A) Representative dot plots showing BrdU staining in the Gr-1^bright (mature neutrophil) population. The numbers shown indicate the percentage of Gr-1^bright cells that were BrdU⁺. (B) The absolute number of BrdU⁺ Gr-1^bright neutrophils in the blood is shown. (C) Neutrophil half-life (t_1/2) in the blood was calculated according to the formulas t_1/2 = ln 2/λ and n_t = n₀e^−λt where n₀ is the number at a given time, n_t is the number t hours later, and λ is the decay constant. The data shown represent the mean ± SEM of n = 10 to 11 mice in each group. *P < .05 compared with control mice at the same time point. ns indicates not significant.