A number of amino acid requiring auxotrophic strains of Salmonella Typhimurium were produced by chemical mutagenesis. One of them, strain 81, was cured of the virulence plasmid and attenuated for mice. This strain had an auxotrophic requirement for serine, which could be used as a marker for the differentiation of the vaccine strain from other isolates in the field. The strain still contained t...

The HIV/AIDS epidemic remains a global health problem, especially in Sub-Saharan Africa. An effective HIV-1 vaccine is therefore badly required to mitigate this ever-expanding problem. Since HIV-1 infects its host through the mucosal surface, a vaccine for the virus needs to trigger mucosal as well as systemic immune responses. Oral, attenuated recombinant Salmonella vaccines offer this potenti...

Salmonellae have evolved several mechanisms to evade host clearance. Here, we describe the influence on bacterial immune escape of the effector protein SopB, which is translocated into the cytosol through a type III secretion system. Wild-type bacteria, as well as the sseC and aroA attenuated mutants exerted a stronger cytotoxic effect on dendritic cells (DC) than their SopB-deficient derivativ...

Pregnancy is a transient immuno-compromised condition which has evolved to avoid the immune rejection of the fetus by the maternal immune system. The altered immune response of the pregnant female leads to increased susceptibility to invading pathogens, resulting in abortion and congenital defects of the fetus and a subnormal response to vaccination. Active vaccination during pregnancy may lead...

Figure 1. Magnetic resonance imaging of the brain demonstrating peripheral enhancement of the scalp abscess alongside noticeable enhancement of the adjacent soft tissues, pathological bone, and underlying pachymeningeal layer enhanced on a coronal T1W slice (left) with a clear intra-osseous edematous edema in keeping with osteomyelitic changes isolating a central bone sequestrum, communicating ...

Live attenuated bacterial vectors, such as Salmonella typhimurium, have shown promise as delivery vehicles for DNA. We have examined two new strains of S. typhimurium and their impact on dendritic cell maturation (CD12-sifA/aroC mutant and WT05-ssaV/aroC, both in TML background). Strain WT05 matured dendritic cells in a more efficient way; caused higher release of cytokines TNF-alpha, IL-12, IL...

Salmonella strains that lack or overproduce DNA adenine methylase (Dam) elicit a protective immune response to different Salmonella species. To generate vaccines against other bacterial pathogens, the dam genes of Yersinia pseudotuberculosis and Vibrio cholerae were disrupted but found to be essential for viability. Overproduction of Dam significantly attenuated the virulence of these two patho...

Salmonella typhimurium zwf mutants lacking glucose 6-phosphate dehydrogenase (G6PD) activity have increased susceptibility to reactive oxygen and nitrogen intermediates as well as attenuated virulence in mice. Abrogation of the phagocyte respiratory burst oxidase during experimental infection with zwf mutant Salmonella causes a prompt restoration of virulence, while inhibition of inducible nitr...

Activation of the extracellularly regulated kinase (ERK) pathway is part of the early biochemical events that follow lipopolysaccharide (LPS) treatment of macrophages or their infection by virulent and attenuated Salmonella strains. Phagocytosis as well as the secretion of invasion-associated proteins is dispensable for ERK activation by the pathogen. Furthermore, the pathways used by Salmonell...

BACKGROUND Egg-associated transmission to humans seems to be characteristic of the Salmonella serotype Enteritidis, explaining why this particular serotype has caused a worldwide pandemic since the mid '80s. Salmonella Enteritidis is much more capable to persistently colonize the laying hen reproductive tract and to survive in the hostile egg white, as compared to other serotypes. PRESENTATIO...