(A) Representative flow cytometry contour plot showing neutrophils in BALF of mice that were treated with either α-IgG control or α-Ly6G, then infected intranasally with 10⁷ CFU of A. baumannii. Neutrophils were identified as live CD45⁺SiglecF^–MHCII^–Ly6C⁺CD11b⁺. (B) Percentage of neutrophils in both female and male infected mice after neutrophil depletion relative to nondepleted levels. n = 6. (C) Fold induction of bacterial numbers 24 hours after infection in female and male mice that were depleted of neutrophils compared with nondepleted controls. n = 6. (D) Representative flow cytometry contour plot showing alveolar macrophages in BALF of mice treated with either liposome-only control or clodronate-loaded liposomes 24 hours prior to intranasal infection with 10⁷ CFU of A. baumannii for 24 hours. Alveolar macrophages were identified as live CD45⁺Ly6C^–CD11c⁺SiglecF⁺. (E) Percentage of alveolar macrophages in both female and male infected mice after alveolar macrophage depletion relative to nondepleted levels. n = 6. (F) Fold induction of bacterial numbers 24 hours after infection in female and male mice that were depleted of alveolar macrophages compared with nondepleted control. n = 5. (G) ROS levels in the airway of clodronate-treated female and male mice 24 hours after infection. n = 10. Graphs show means with SEM. Each point represents a mouse. Data are from at least 2 independent experiments. *P < 0.05, and **P < 0.01. A nonparametric Mann-Whitney U test was used to assess differences between groups.