A conserved and immunodominant lipoprotein of Francisella tularensis is proinflammatory but not essential for virulence.

Francisella tularensis is a highly virulent bacterium that causes tularemia, a disease that is often fatal if untreated. A live vaccine strain (LVS) of this bacterium is attenuated for virulence in humans but produces lethal disease in mice. F.

Francisella tularensis has a significant extracellular phase in infected mice.

The ability of Francisella tularensis to replicate in macrophages has led many investigators to assume that it resides primarily intracellularly in the blood of mammalian hosts. We have found this supposition to be untrue. In almost all cases, the majority of F.

Mac-1+ cells are the predominant subset in the early hepatic lesions of mice infected with Francisella tularensis.

The cell composition of early hepatic lesions of experimental murine tularemia has not been characterized with specific markers. The appearance of multiple granulomatous-necrotic lesions in the liver correlates with a marked increase in the levels of serum alanine transferase and lactate dehydrogenase. Francisella tularensis, detected by specific antibodies, can be first noted by day 1 and becomes associated with the lesions by 5 days postinoculation.

Deletion of TolC orthologs in Francisella tularensis identifies roles in multidrug resistance and virulence.

The Gram-negative bacterium Francisella tularensis is the causative agent of tularemia. Interest in this zoonotic pathogen has increased due to its classification as a category A agent of bioterrorism, but little is known about the molecular mechanisms underlying its virulence, and especially what secretion systems and virulence factors are present. In this study, we characterized two genes in the F.

The live vaccine strain of Francisella tularensis replicates in human and murine macrophages but induces only the human cells to secrete proinflammatory cytokines.

Francisella tularensis is the highly infectious agent of tularemia, a disease that can prove fatal in humans. An attenuated live vaccine strain (LVS) of this bacterium is avirulent in man but produces lethal illness in mice. As a step toward understanding the species specificity of the LVS, we compared its interactions with murine and human leukocytes.

Francisella tularensis selectively induces proinflammatory changes in endothelial cells.

Naturally acquired infections with Francisella tularensis, the bacterial agent of tularemia, occur infrequently in humans. However, the high infectivity and lethality of the organism in humans raise concerns that it might be exploited as a weapon of bioterrorism. Despite this potential for illicit use, the pathogenesis of tularemia is not well understood.