FIG 6.

Phagocytic and killing activities, assessed in peritoneal macrophages from ccl3^−/− and WT mice. (A) Numbers of bacteria recovered from lysed macrophages after a 1-h ingestion period in culture and a 1-h exposure to gentamicin to kill extracellular bacteria (a measure of phagocytosis) were quantified by colony counting. Phagocytosis was significantly impaired in ccl3^−/− macrophages (**, P < 0.01 as determined by a Mann-Whitney U test), compared to macrophages from WT mice. (B) Intracellular bacteria recovered 3 h after NTHi ingestion and gentamicin treatment as a percentage of the number observed at 1 h (a measure of intracellular killing). Bacterial killing by ccl3^−/− macrophages and that by WT macrophages were similar (Mann-Whitney U test) (n = 6 per time point and strain; bars and error bars represent means ± SEM). ns, nonsignificant.