Live M. tuberculosis infection causes dendritic cell death and DNA fragmentation, without nuclear fragmentation. A - B. Dendritic cells (DCs) were infected, at MOI 10 with live/dead H37Ra or live/dead H37Rv. (U = uninfected, LH37Ra = live H37Ra, sH37Ra = streptomycin-killed H37Ra, LH37Rv = live H37Rv, iH37Rv = γ-irradiated H37Rv.) Cell death was measured by propidium iodide exclusion (A) 72 h post-infection or (B) 24 h post-infection on a GE IN Cell Analyzer 1000. (A - B) are means (± SEM) of 3 pooled donors. * p < 0.05 vs. Uninfected. C. DCs were infected with live H37Ra at MOI 1, 5 or 10. Cell death was measured by propidium iodide exclusion 72 h after infection. Staurosporine was used as a positive control for cell death. * p < 0.05 vs. uninfected, ns - not significantly different from uninfected. D. DCs were infected with live H37Ra at MOI 1, 5 or 10. DNA fragmentation was measured by Cell Death ELISA 72 h after infection. * p < 0.05 vs. Uninfected, ns - not significantly different from uninfected. E. DCs were infected with live H37Ra at MOI 10 for 72 h. Nuclei were stained with Hoechst and visualised by fluorescence microscopy. Cycloheximide and staurosporine were used as positive controls for nuclear fragmentation. (C - E) are 1 representative donor of 3, showing means (± SEM) of 3 independent wells.
Ryan et al. BMC Microbiology 2011 11:237 doi:10.1186/1471-2180-11-237