FIG 2.

NMII inhibits DNA fragmentation in primary mouse BMNs. BMNs were infected with NMII at an MOI of 100 for 18 h. (A) Uninfected and infected cells were stained with TUNEL (red) to detect DNA fragmentation. Cells were also labeled by IFA using antibodies directed against C. burnetii (green). DAPI was used to stain DNA (blue). Uninfected neutrophils exhibited significant DNA fragmentation, while there were no detectable TUNEL-positive cells during NMII infection. (B) The percentage of apoptotic cells was determined at 4 and 18 hpi by counting the number of TUNEL-positive cells. A total of 200 cells per coverslip were counted in three separate experiments for each time point. Results are expressed as percent apoptosis, and error bars represent the standard deviation from the mean. *, P < 0.05; **, P < 0.01.