Brucellosis Vaccines: Assessment of Brucella melitensis Lipopolysaccharide Rough Mutants Defective in Core and O-Polysaccharide Synthesis and Export

Background: The brucellae are facultative intracellular bacteria that cause brucellosis, one of the major neglected zoonoses. In endemic areas, vaccination is the only effective way to control this disease. Brucella melitensis Rev 1 is a vaccine effective against the brucellosis of sheep and goat caused by B. melitensis, the commonest source of human infection. However, Rev 1 carries a smooth lipopolysaccharide with an O-polysaccharide that elicits antibodies interfering in serodiagnosis, a major problem in eradication campaigns. Because of this, rough Brucella mutants lacking the O-polysaccharide have been proposed as vaccines. Methodology/Principal Findings: To examine the possibilities of rough vaccines, we screened B. melitensis for lipopolysaccharide genes and obtained mutants representing all main rough phenotypes with regard to core oligosaccharide and O-polysaccharide synthesis and export. Using the mouse model, mutants were classified into four attenuation patterns according to their multiplication and persistence in spleens at different doses. In macrophages, mutants belonging to three of these attenuation patterns reached the Brucella characteristic intracellular niche and multiplied intracellularly, suggesting that they could be suitable vaccine candidates. Virulence patterns, intracellular behavior and lipopolysaccharide defects roughly correlated with the degree of protection afforded by the mutants upon intraperitoneal vaccination of mice. However, when vaccination was applied by the subcutaneous route, only two mutants matched the protection obtained with Rev 1 albeit at doses one thousand fold higher than this reference vaccine. These mutants, which were blocked in O-polysaccharide export and accumulated internal O-polysaccharides, stimulated weak anti-smooth lipopolysaccharide antibodies. Conclusions/Significance: The results demonstrate that no rough mutant is equal to Rev 1 in laboratory models and question the notion that rough vaccines are suitable for the control of brucellosis in endemic areas.This work was funded by the European Commission (Research Contract QLK2-CT-2002-00918) and the Ministerio de Ciencia y Tecnología of Spain (Proyecto AGL2004-01162/GAN)

The Lipopolysaccharide Core of Brucella abortus Acts as a Shield Against Innate Immunity Recognition

Innate immunity recognizes bacterial molecules bearing pathogen-associated molecular patterns to launch inflammatory responses leading to the activation of adaptive immunity. However, the lipopolysaccharide (LPS) of the gram-negative bacterium Brucella lacks a marked pathogen-associated molecular pattern, and it has been postulated that this delays the development of immunity, creating a gap that is critical for the bacterium to reach the intracellular replicative niche. We found that a B. abortus mutant in the wadC gene displayed a disrupted LPS core while keeping both the LPS O-polysaccharide and lipid A. In mice, the wadC mutant induced proinflammatory responses and was attenuated. In addition, it was sensitive to killing by non-immune serum and bactericidal peptides and did not multiply in dendritic cells being targeted to lysosomal compartments. In contrast to wild type B. abortus, the wadC mutant induced dendritic cell maturation and secretion of pro-inflammatory cytokines. All these properties were reproduced by the wadC mutant purified LPS in a TLR4-dependent manner. Moreover, the core-mutated LPS displayed an increased binding to MD-2, the TLR4 co-receptor leading to subsequent increase in intracellular signaling. Here we show that Brucella escapes recognition in early stages of infection by expressing a shield against recognition by innate immunity in its LPS core and identify a novel virulence mechanism in intracellular pathogenic gram-negative bacteria. These results also encourage for an improvement in the generation of novel bacterial vaccines

Overview of recent TJ-II stellarator results

The main results obtained in the TJ-II stellarator in the last two years are reported. The most important topics investigated have been modelling and validation of impurity transport, validation of gyrokinetic simulations, turbulence characterisation, effect of magnetic configuration on transport, fuelling with pellet injection, fast particles and liquid metal plasma facing components. As regards impurity transport research, a number of working lines exploring several recently discovered effects have been developed: the effect of tangential drifts on stellarator neoclassical transport, the impurity flux driven by electric fields tangent to magnetic surfaces and attempts of experimental validation with Doppler reflectometry of the variation of the radial electric field on the flux surface. Concerning gyrokinetic simulations, two validation activities have been performed, the comparison with measurements of zonal flow relaxation in pellet-induced fast transients and the comparison with experimental poloidal variation of fluctuations amplitude. The impact of radial electric fields on turbulence spreading in the edge and scrape-off layer has been also experimentally characterized using a 2D Langmuir probe array. Another remarkable piece of work has been the investigation of the radial propagation of small temperature perturbations using transfer entropy. Research on the physics and modelling of plasma core fuelling with pellet and tracer-encapsulated solid-pellet injection has produced also relevant results. Neutral beam injection driven Alfvénic activity and its possible control by electron cyclotron current drive has been examined as well in TJ-II. Finally, recent results on alternative plasma facing components based on liquid metals are also presentedThis work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under Grant Agreement No. 633053. It has been partially funded by the Ministerio de Ciencia, Inovación y Universidades of Spain under projects ENE2013-48109-P, ENE2015-70142-P and FIS2017-88892-P. It has also received funds from the Spanish Government via mobility grant PRX17/00425. The authors thankfully acknowledge the computer resources at MareNostrum and the technical support provided by the Barcelona S.C. It has been supported as well by The Science and Technology Center in Ukraine (STCU), Project P-507F

Effect of the time of diagnosis on outcome in patients with acute venous thromboembolism

The influence of the day of diagnosis (weekends vs. weekdays) on outcome in patients with acute venous thromboembolism (VTE) has not been thoroughly studied. We used the RIETE database to compare the clinical characteristics, treatment details, and mortality rate at 7 and 30 days, of all patients diagnosed with acute VTE on weekends versus those diagnosed on weekdays. Up to January 2010, 30,394 patients were included in RIETE, of whom 5,479 (18%) were diagnosed on weekends. Most clinical characteristics were similar in both groups, but patients diagnosed on weekends had less often cancer (20% vs. 22%; p=0.004), and presented more likely with pulmonary embolism (PE) than those diagnosed on weekdays (52% vs. 47%; p <0.001). Most patients in both groups received initial therapy with low-molecular-weight heparin (90% and 91%, respectively; p=0.01), then switched to vitamin K antagonists (72% and 71%, respectively; p=0.007). The 7-day mortality rate in patients presenting with PE was 2.75% in those diagnosed on weekends versus 3.00% in those diagnosed on weekdays (p=0.49). At 30 days, the mortality rate was 6.51% versus 6.06%, respectively (p=0.38). In patients presenting with deep vein thrombosis alone, the 7-day mortality rate in those diagnosed on weekends was 1.04% versuss 0.66% in those diagnosed on weekdays (p=0.053). The mortality rate at 30 days was of 3.41% versus 2.88% (p=0.14), respectively. In RIETE, the clinical characteristics, treatment strategies, and 7- and 30-day mortality rates of patients diagnosed on weekends were similar to those in patients diagnosed on weekdays

Effect of the time of diagnosis on outcome in patients with acute venous thromboembolism

The influence of the day of diagnosis (weekends vs. weekdays) on outcome in patients with acute venous thromboembolism (VTE) has not been thoroughly studied. We used the RIETE database to compare the clinical characteristics, treatment details, and mortality rate at 7 and 30 days, of all patients diagnosed with acute VTE on weekends versus those diagnosed on weekdays. Up to January 2010, 30,394 patients were included in RIETE, of whom 5,479 (18%) were diagnosed on weekends. Most clinical characteristics were similar in both groups, but patients diagnosed on weekends had less often cancer (20% vs. 22%; p=0.004), and presented more likely with pulmonary embolism (PE) than those diagnosed on weekdays (52% vs. 47%; p <0.001). Most patients in both groups received initial therapy with low-molecular-weight heparin (90% and 91%, respectively; p=0.01), then switched to vitamin K antagonists (72% and 71%, respectively; p=0.007). The 7-day mortality rate in patients presenting with PE was 2.75% in those diagnosed on weekends versus 3.00% in those diagnosed on weekdays (p=0.49). At 30 days, the mortality rate was 6.51% versus 6.06%, respectively (p=0.38). In patients presenting with deep vein thrombosis alone, the 7-day mortality rate in those diagnosed on weekends was 1.04% versuss 0.66% in those diagnosed on weekdays (p=0.053). The mortality rate at 30 days was of 3.41% versus 2.88% (p=0.14), respectively. In RIETE, the clinical characteristics, treatment strategies, and 7- and 30-day mortality rates of patients diagnosed on weekends were similar to those in patients diagnosed on weekdays