FIG 2.
Cftr deficiency impairs intracellular killing of S. aureus in macrophages in vivo. (A) Alveolar macrophages (AM) and bone marrow-derived macrophages (BMDM) from wild-type (WT) or CF (Cftr knockout [CftrKO]) mice were infected with S. aureus for the indicated times. After infection, gentamicin was added and cells were incubated for an additional 1 h to ensure killing of extracellular bacteria. Cells were then washed and lysed, and the numbers of viable S. aureus colonies derived from lysates were determined. Data are expressed as the mean results ± SD from 4 experiments. *, P < 0.05 by one-way ANOVA and Student-Newman-Keuls test. (B) Wild-type and CF mice were intranasally infected with S. aureus, and alveolar macrophages were isolated by bronchial lavage after 6 and 12 h. Alveolar macrophages were incubated with gentamicin for 1 h, and the numbers of internalized bacteria were determined. (C, D) The infection experiments were repeated with S. aureus strain Newman, with very similar results as for the clinical S. aureus strain. Values are the mean results ± SD from 4 independent experiments; *, P < 0.05 by one-way ANOVA and Student-Newman-Keuls test.