Vaccine breakthrough hypoxemic COVID-19 pneumonia in patients with auto-Abs neutralizing type I IFNs

Life-threatening `breakthrough' cases of critical COVID-19 are attributed to poor or waning antibody response to the SARS- CoV-2 vaccine in individuals already at risk. Pre-existing autoantibodies (auto-Abs) neutralizing type I IFNs underlie at least 15% of critical COVID-19 pneumonia cases in unvaccinated individuals; however, their contribution to hypoxemic breakthrough cases in vaccinated people remains unknown. Here, we studied a cohort of 48 individuals ( age 20-86 years) who received 2 doses of an mRNA vaccine and developed a breakthrough infection with hypoxemic COVID-19 pneumonia 2 weeks to 4 months later. Antibody levels to the vaccine, neutralization of the virus, and auto- Abs to type I IFNs were measured in the plasma. Forty-two individuals had no known deficiency of B cell immunity and a normal antibody response to the vaccine. Among them, ten (24%) had auto-Abs neutralizing type I IFNs (aged 43-86 years). Eight of these ten patients had auto-Abs neutralizing both IFN-a2 and IFN-., while two neutralized IFN-omega only. No patient neutralized IFN-ss. Seven neutralized 10 ng/mL of type I IFNs, and three 100 pg/mL only. Seven patients neutralized SARS-CoV-2 D614G and the Delta variant (B.1.617.2) efficiently, while one patient neutralized Delta slightly less efficiently. Two of the three patients neutralizing only 100 pg/mL of type I IFNs neutralized both D61G and Delta less efficiently. Despite two mRNA vaccine inoculations and the presence of circulating antibodies capable of neutralizing SARS-CoV-2, auto-Abs neutralizing type I IFNs may underlie a significant proportion of hypoxemic COVID-19 pneumonia cases, highlighting the importance of this particularly vulnerable population

De quelle façon un vin japonais ''kôshû'' peut-il s'insérer dans le marché français tout en conservant son identité propre ?

Management du tourismeThèses et écrits académique

Ingénierie d'une protéase monospécifique pour le diagnostic du glucose sanguin

Le dosage sanguin de la glycémie via le taux d hémoglobine glyquée (HbA1c) est un paramètre-clé de la surveillance du diabète à long terme. Roche Diagnostics GmbH s est engagé avec la Fédération Internationale de Chimie Clinique et de Médecine de Laboratoire (IFCC) à développer un système standard de référence international de contrôle de la glycémie. L endopeptidase glutamique (GluC) de la souche V8 de Staphylococus aureus (EC 3.4.21.19) est utilisée pour la digestion de l HbA1c. L objectif de cette thèse de doctorat est d augmenter la vitesse d hydrolyse de la GluC par évolution moléculaire tout en préservant ses caractéristiques enzymatiques originelles (spécificité et stabilité) dans les conditions standardisées du test fonctionnel de l HbA1c. La construction de librairies de plusieurs milliers de variants, couplée à un criblage multiparamètre, a permis d isoler un mutant de la GluC qui comporte les propriétés recherchées. Ce variant a été exprimé chez B. subtilis par sécrétion extracellulaire et purifié par chromatographie d affinité Ni-NTA. Il a été ensuite caractérisé après activation par autoprotéolyse. Le variant présente une activité spécifique 3 fois supérieure et une constante d affinité (Km) trois fois meilleure à celle de la GluC sauvage pour le substrat synthétique: Z-Phe-Leu-Glu-pNa dans un tampon de Tris-HCl à pH 7.8. Le variant est 4 fois plus actif dans un tampon d acétate d ammonium à pH 4.3 avec l hexapeptide de l hémoglobine pour substrat. Il est également plus stable à 50C. Bien que plus actif que la GluC sauvage en présence de substrats synthétiques, le variant isolé est moins performant d un point de vue activité, affinité et spécificité de coupure pour l hexapeptide de l hémoglobine entière.The blood glucose determination via the rate of glycated hemoglobin (HbA1c) is a key-parameter for long-term diabetes care. Roche Diagnostics GmbH committed itself with the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) to develop an international reference standard system for blood sugar control. The glutamyl endopeptidase (GluC) from the V8 strain of Staphylococus aureus (EC 3.4.21.19) is used for the HbA1c digestion. The aim of this phD project is to increase the hydrolysis speed of the GluC by directed evolution by keeping its original enzymatic characteristics (specificity and stability) in the standard conditions of the functional hemoglobin test. A variant with the improved enzymatic features was isolated and identified after the construction and the multiparameter screening of libraries of thousands of mutants. This variant of the glutamyl endopeptidase was expressed in B. subtilis by extracellular secretion, and then purified by Ni-NTA affinity chromatography. It was then characterized after activation by autoproteolysis. The specific activity of the variant is three times enhanced and the affinity constant (Km) is 3 times improved in a Tris-HCl buffer at pH 7.8, compared to the wild type glutamyl endopeptidase. The specific activity is four times better in ammonium acetate buffer at pH 4.3 with the hemoglobin hexapeptide as substrate. It is also more stable at 50C. However, although the variant is more active with synthetic substrate, it is less competitive than the wild type V8-Glutamyl endopeptidase regarding the activity, affinity and cutting specificity for the hexapeptide of the whole hemoglobin. Experiments are still discussed to optimize the conditions of the HbA1c test.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Wave Attenuation by Cultivated Seaweeds: a Linearized Analytical Solution

An analytical framework is presented to describe the attenuation of regular and irregular waves propagating over floating seaweed farms. Kelp blades suspending on the longlines are modeled, as a first approximation, as rigid bars rotating around their upper ends. Assuming small-amplitude blade motions under low to moderate sea conditions, the frequency transfer function of the rotations can be obtained, with quadratic drag loads linearized. Subsequently, the hydrodynamic problem with regular waves propagating over suspended seaweed canopies is formulated using the continuity equation and linearized momentum equations with additional source terms within the vegetation region. Analytical solutions are obtained for the regular waves with their heights decaying exponentially as they propagate over the canopy. These analytical solutions are utilized as the basis to predict the wave attenuation of irregular waves while stochastic linearization of the quadratic drag loads is employed. The wave power spectral density is also seen to decay exponentially over the canopy. The present solutions can also be extended to include the elastic deformation of the vegetation blades

Refining the mandibular osteoradionecrosis rat model by in vivo longitudinal µCT analysis

International audienceAbstract Osteoradionecrosis (ORN) is one of the most feared side effects of radiotherapy following cancers of the upper aero-digestive tract and leading to severe functional defects in patients. Today, our lack of knowledge about the physiopathology restricts the development of new treatments. In this study, we refined the ORN rat model and quantitatively studied the progression of the disease. We tested the impact of radiation doses from 20 to 40 Gy, delivered with incident 4MV X-ray beams on the left mandible of the inbred Lewis Rat. We used micro-computed tomography (µCT) to obtain in vivo images for longitudinal bone imaging and ex vivo images after animal perfusion with barium sulphate contrast agent for vessel imaging. We compared quantification methods by analyzing 3D images and 2D measurements to determine the most appropriate and precise method according to the degree of damage. We defined 25 Gy as the minimum irradiation dose combined with the median molar extraction necessary to develop non-regenerative bone necrosis. µCT image analyses were correlated with clinical and histological analyses. This refined model and accurate methods for bone and vessel quantification will improve our knowledge of the progression of ORN pathology and allow us to test the efficacy of new regenerative medicine procedures

Inorganic/organic nanocomposites: Reaching a high filler content without increasing viscosity using core-shell structured nanoparticles

International audienceExtensive research is being conducted on the development of inorganic/organic nanocomposites for a wide variety of applications in microelectronics, biotechnologies, photonics, adhesives, or optical coatings. High filler contents are usually required to fully optimize the nanocomposites properties. However, numerous studies demonstrated that traditional composite viscosity increases with increasing the filler concentration reducing therefore significantly the material processability. In this work, we synthesized inorganic/organic core-shell nanocomposites with different shell thicknesses. By reducing the shell thickness while maintaining a constant core size, the nanopar- ticle molecular mass decreases but the nanocomposite filler fraction is correlatively increased. We performed viscosity measurements, which clearly highlighted that intrinsic viscosity of hybrid nanoparticles decreases as the molecular mass decreases, and thus, as the filler fraction increases, as opposed to Einstein predictions about the viscosity of traditional inorganic/polymer two-phase mixtures. This exceptional behavior, modeled by Mark-Houwink-Sakurada equation, proves to be a significant breakthrough for the development of industrializable nanocomposites with high filler contents