Figure 6. Bactericidal ability of inflammatory cells in young and aged mice. Young and aged mice were infected intratracheally with 5 × 106 CFU of LAC-4. (A) MPO levels in the lung homogenate supernatants at 0 h and 24 hpi were detected by ELISA. (B) ROS production in neutrophils (CD11b+ Ly6G+ cells) in BALF at 24 hpi was stained by a ROS detection reagent (carboxy-H2DCFDA) and assessed by flow cytometry. Data are presented as mean ± SEM of four or five mice per condition and represent one of 2 independent experiments. Statistical analyses were performed by Student’s t test. *, P<0.05, **, P<0.01.