Figure 5.

Nuclear DNA fragmentation of L. pneumophila-infected A549 cells detected by the TUNEL method. TUNEL-positive A549 cell numbers with each stimulus are presented. Cells were observed with a confocal laser scanning microscopy. More than 500 cells were counted from 10 randomized high-power fields, and TUNEL-positive cells were expressed as a ratio per total number of cells. Symbols: ▫, virulent strain AA100jm; ▪, avirulent strain dotO mutant. Data are mean ± SD of three different experiments. * P < 0.05.