Pretreatment with SF1670 increases the efficacy of granulocyte transfusion in neutropenia-related pneumonia. (A) Mouse bone marrow–derived neutrophils were pretreated with or without SF1670 ([SF]; 250nM) for 30 minutes at 37°C, washed twice with PBS, and then intravenously injected to neutropenic mice that had been challenged with 10⁵ CFU of E coli for 5 hours. Mice not receiving granulocyte transfusion were used as control. BALF was harvested 24 hours after each challenge. BALF was serially diluted and spread on plates. Colonies were counted next day. **P < .01 vs control; ^##P < .01 vs DMSO. (B) Histologic analysis of lungs reveals bacterial colonies and polymerized fibrin in the pulmonary parenchyma (indicated by an arrow). Lung sections were stained with H&E. (C) Pulmonary edema formation was quantified as the percentage of edema in the total parenchymal region using IPLab imaging software as described previously.²⁹  *P < .05, **P < .01 vs control; ^#P < .05 vs DMSO. (D) BALF total protein level. Protein accumulated in the inflamed lung was measure using a protein assay kit (Bio-Rad Laboratories). *P < .05, **P < .01 vs control; ^##P < .01 vs DMSO. (E) Survival rates of mice infected with E coli. Age- and sex-matched neutropenia-related pneumonia mice were adoptively transferred with neutrophils pretreated with or without SF1670. Survival rates were analyzed using the Kaplan-Meier survival curves and log-rank test. * P < .05 vs DMSO. (F) Pretreatment with SF1670 augments the bactericidal capability of the host in both S pneumoniae- and S aureus-induced neutropenia-related pneumonia. The experiments were conducted essentially as described in panel A. The pneumonia was induced by 10⁶ CFU of S pneumonia or 10⁷ CFU of S aureus. (G) Survival rates of mice infected with S aureus. The experiment was conducted essentially as described in panel E. *P < .05 vs DMSO-pretreated neutrophils.