FIG. 1.
(A) H. pylori interaction with human macrophages. Human monocytes were differentiated into macrophages by incubating them for 0, 24, 48, 96, or 120 h (0, 1, 2, 4, or 5 days) in RPMI with HI FCS. The macrophages were infected with H. pylori P12 (black fill), H. pylori cag PAI (hatched), or N. gonorrhoeae N303 (white fill) for 2 h at 37°C. Samples were fluorescently immunostained for confocal laser-scanning microscopic analysis. The percentage of infected cells containing at least one intracellular bacterium was determined (percent infected cells containing intracellular bacteria). Results are the mean of at least three independent experiments. (B) Bacterial uptake by J774a cells. The murine J774a macrophage cells were infected with either H. pylori P12, PAI, or N. gonorrhoeae N303 alone or were infected with either H. pylori P12 or PAI for 2 h before the addition of N. gonorrhoeae N303. In these cases the uptake of N303 was assessed. The bacterial uptake was determined by using laser confocal microscopy. The percentage of infected cells containing at least one intracellular bacterium was determined. Results are the mean of at least three independent experiments.