(A) Bacterial CFU were determined at 6 hours after i.v. infection with P. aeruginosa in lung after prophylactic antibody treatment. n = 6. Error bars represent SEM. One-way ANOVA statistical analysis was performed on data points; multiple comparisons were performed between indicated columns. *P = 0.0255, **P = 0.0109. (B) Mice were stained for CD45 (blue) for all hematopoietic cells and Ly6G (red) for neutrophils. The percentage of neutrophil-negative but CD45-positive cells containing P. aeruginosa–GFP was assessed at 1 hour after infection (number of FOV = 3, n = 3). Error bars represent SEM. (C) Flow cytometry was performed to identify Ly6G-negative cells that contained P. aeruginosa–GFP. Eosinophils are intermediate for Siglec-F and high for CD11b, while monocytes are Siglec-F negative and Cd11b high (n = 3, 3 FOV). Error bars represent SEM. One-way ANOVA statistical analysis was performed; P = 0.0667. (D) Whole lung homogenates were used to determine the cytokine/chemokine milieu 6 hours after infection with P. aeruginosa. One-way ANOVA analysis was performed on the indicated columns. P < 0.05 is significant. Error bars represent SEM. *P = 0.0373, **P = 0.0067, ***P = 0.0003. (E) Survival analysis of mice prophylactically treated with therapeutic antibodies and then subsequently infected i.v. with P. aeruginosa strain 6077. Mantel-Cox test was performed. There was a significant difference between MEDI3902-treated mice and IgG control mice (P < 0.0001). There was a significant difference between anti-PcrV–treated mice and IgG control mice (P < 0.0001). There was no significant difference between IgG control mice and anti-Psl–treated mice (P = 0.3722). Finally, there was a significant difference between mice treated with a mixture of the antibodies (anti-Psl + anti-PcrV) and MED3902-treated mice (P = 0.0491). Error bars represent SEM; n = 8 mice per group. All experiments were repeated 3 times unless otherwise indicated.