Francisella tularensis induces cytopathogenicity and apoptosis in murine macrophages via a mechanism that requires intracellular bacterial multiplication

The murine macrophage-like cell line J774.A1 ingests and allows intracellul ar growth of Francisella tularensis. We demonstrate that, after 24 h of inf ection, a pronounced cytopathogenicity resulted and the J774 cells were und ergoing apoptosis. Despite this host cell apoptosis, no decrease in bacteri al numbers was observed. When internalization of bacteria was prevented or intracellularly Located F. tularensis bacteria were eradicated within 12 h, the progression of host cell cytopathogenicity and apoptosis was prevented .