Humoral and cellular immune responses to Yersinia pestis Pla antigen in humans immunized with live plague vaccine.

Background: To establish correlates of human immunity to the live plague vaccine (LPV), we analyzed parameters of cellular and antibody response to the plasminogen activator Pla of Y. pestis. This outer membrane protease is an essential virulence factor that is steadily expressed by Y.

Evaluation of protective potential of Yersinia pestis outer membrane protein antigens as possible candidates for a new-generation recombinant plague vaccine.

Plague caused by Yersinia pestis manifests itself in bubonic, septicemic, and pneumonic forms. Although the U.S.

Administration of a nitric oxide donor inhibits mglA expression by intracellular Francisella tularensis and counteracts phagosomal escape and subversion of TNF-α secretion.

Francisella tularensis is a highly virulent intracellular bacterium capable of rapid multiplication in phagocytic cells. Previous studies have revealed that activation of F. tularensis-infected macrophages leads to control of infection and reactive nitrogen and oxygen species make important contributions to the bacterial killing.

Improved detection of Bartonella DNA in mammalian hosts and arthropod vectors by real-time PCR using the NADH dehydrogenase gamma subunit (nuoG).

We used a whole-genome scanning technique to identify the NADH dehydrogenase gamma subunit (nuoG) primer set that is sensitive and specific enough to detect a diverse number of Bartonella species in a wide range of environmental samples yet maintains minimal cross-reactivity to mammalian host and arthropod vector organisms.

Tetraacylated lipopolysaccharide of Yersinia pestis can inhibit multiple Toll-like receptor-mediated signaling pathways in human dendritic cells.

Background: Yersinia pestis, the causative agent of plague, showed a temperature-dependent change in lipid A composition, with a reduced degree of acylation when bacteria were grown at 37 degrees C (tetraacylated) versus ambient temperature (hexaacylated).

Methods: Human monocytes and monocyte-derived dendritic cells (DCs) were exposed to Y. pestis grown at 26 degrees C or 37 degrees C, to their corresponding lipopolysaccharides (LPS-26 degrees C or LPS-37 degrees C), and to ligands of different Toll-like receptors (TLRs), such as LPS from Escherichia coli (TLR4), lipoprotein (TLR2), polyinosinic-polycytidylic acid (poly-IC) (TLR9), and their combinations.

Amino acid and structural variability of Yersinia pestis LcrV protein.

The LcrV protein is a multifunctional virulence factor and protective antigen of the plague bacterium and is generally conserved between the epidemic strains of Yersinia pestis. We investigated the diversity in the LcrV sequences among non-epidemic Y. pestis strains which have a limited virulence in selected animal models and for humans.

Evaluation of a Yersinia pestis mutant impaired in a thermoregulated type VI-like secretion system in flea, macrophage and murine models.

Type VI secretion systems (T6SSs) have been identified recently in several Gram-negative organisms and have been shown to be associated with virulence in some bacterial pathogens. A T6SS of Yersinia pestis CO92 (locus YPO0499-YPO0516) was deleted followed by investigation of the phenotype of this mutation. We observed that this T6SS locus of Y.

Drosophila melanogaster as a model for elucidating the pathogenicity of Francisella tularensis.

Drosophila melanogaster is a widely used model organism for research on innate immunity and serves as an experimental model for infectious diseases. The aetiological agent of the zoonotic disease tularaemia, Francisella tularensis, can be transmitted by ticks and mosquitoes and Drosophila might be a useful, genetically amenable model host to elucidate the interactions between the bacterium and its arthropod vectors. We found that the live vaccine strain of F.