Biology subjects

Thibault, V.

Publications and source records attributed to Thibault, V..

2 recordsLinked to original sources

bioRxiv2021

SARS-CoV2 envelop proteins reshape the serological responses of COVID-19 patients

The SARS-CoV-2 pandemic has elicited a unique international mobilization of the scientific community to better understand this coronavirus and its associated disease and to develop efficient tools to combat infection. Similar to other coronavirae, SARS-CoV-2 hijacks the host cell complex secretory machinery to produce properly folded viral proteins that will compose the nascent virions; including Spike, Envelope and Membrane proteins, the most exposed membrane viral proteins to the host immune system. Antibody response is part of the anti-viral immune arsenal that infected patients develop to fight viral particles in the body. Herein, we investigate the immunogenic potential of Spike (S), Envelope (E) and Membrane (M) proteins using a human cell-based system to mimic membrane insertion and N-glycosylation. We show that both S and M proteins elicit the production of specific IgG, IgM and IgA in SARS-CoV-2 infected patients. Elevated Ig responses were observed in COVID+ patients with moderate and severe forms of the disease. Finally, when SARS-CoV-2 Spike D614 and G614 variants were compared, reduced Ig binding was observed with the Spike G614 variant. Altogether, this study underlines the needs for including topological features in envelop proteins to better characterize the serological status of COVID+ patients, points towards an unexpected immune response against the M protein and shows that our assay could represent a powerful tool to test humoral responses against actively evolving SARS-CoV-2 variants and vaccine effectiveness.

cell biology↗

bioRxiv2020

Performances of NeuMoDx, a random-access system for HBV-DNA and HCV-RNA quantification

Viral loads (VL) monitoring for hepatitis B and C is essential to evaluate disease progression and treatment response. Automated, random-access rapid systems are becoming standard to provide reliable VL to clinicians. The aim of this study was to evaluate the analytical performances of the recently launched NeuMoDx for HBV-DNA and HCV-RNA quantification. Clinical samples routinely quantified on the Beckman-Veris system were either retrospectively (frozen samples; HBV n=178, HCV n=249), or in parallel (fresh primary tubes; HBV n=103, HCV n=124) tested using NeuMoDx. Linearity range was assessed on serial dilutions of high tittered plasmas containing different genotypes for HBV (A-E, n=10) and HCV (1a-b, 2-5, n=12). Overall test failure, mostly internal control amplification failure, was 2.3% and was not influenced by matrix types. For HBV-VL, Kappa agreement was 74%, with 27 (12.6%) discrepancies. Correlation between HBV assays on 72 quantified samples by both methods was excellent (r=0.963) with a mean bias (NeuMoDx-Veris) of 0.21 log IU/mL. For HCV-VL, Kappa agreement reached 94%, with 9 (2.8%) discrepancies. The r-correlation factor between assays on 104 samples was 0.960 with a mean bias of -0.14 log IU/mL (NeuMoDx-Veris). Serial dilutions confirmed the claimed linear ranges for all HBV and HCV genotypes. The mean turnaround time was 72 [55-101] for HBV and 96 [78-133] for HCV. These results obtained on the NeuMoDx confirmed the overall good functionality of the system with a short turn-around-time, full traceability and easy handling. These results on HBV- and HCV-VL look promising and should be challenged with further comparisons.

microbiology↗