The Experts below are selected from a list of 58176 Experts worldwide ranked by ideXlab platform
Matthias Niedrig - One of the best experts on this subject based on the ideXlab platform.
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development of one step quantitative reverse transcription pcr for the rapid detection of flaviViruses
Virology Journal, 2013Co-Authors: Pranav Patel, Olfert Landt, Marco Kaiser, Oumar Faye, Tanja Koppe, Ulrich Lass, Amadou A Sall, Matthias NiedrigAbstract:The genus FlaviVirus includes several pathogenic agents that cause severe illness in humans. Re-emergence of West Nile Virus in Europe and continuous spread of certain flaviViruses such as Dengue, yellow fever and Japanese encephalitis Viruses represent a global danger to public health. Therefore, a rapid and accurate molecular method is required for diagnostics and epidemiological surveillance of flaviViruses. A Pan-Flavi quantitative RT-PCR assay using a Locked-Nucleic Acid probe targeting the flaviVirus NS5 gene was developed and optimized to detect a wide range of flaviViruses simultaneously. The specificity and sensitivity of the Pan-Flavi assay were tested using RNA of different flaviViruses and non-flaviViruses. Furthermore, the assay was compared directly to flaviVirus species-specific assays for the ability to detect flaviViruses sensitively. Two degenerate primers and one Locked-Nucleic Acids probe were designed to amplify most of the flaviViruses. To increase the specificity and fluorescence signal of the Pan-Flavi assay for detection of yellow fever Virus and Dengue Virus 4, additional primers and probes were included. Viral RNA of thirty different flaviViruses was detected, verifying the broad range specificity. The testing of this assay was successful, using standard plasmid and RNA dilutions of yellow fever Virus vaccine strain, Dengue Virus 1 and tick-borne encephalitis Virus, with a sensitivity limit of 10–100 genome copies/reaction. Also comparatively good results were achieved for detecting different flaviViruses by the Pan-Flavi assay when compared to the flaviVirus species-specific assays. The assay is rapid, broad-range flaviVirus-specific and highly sensitive making it a valuable tool for rapid detection of flaviViruses in livestock samples, epidemiological studies or as useful complement to single flaviVirus-specific assays for clinical diagnosis.
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use of a short fragment of the c terminal e gene for detection and characterization of two new lineages of Dengue Virus 1 in india
Journal of Clinical Microbiology, 2006Co-Authors: Cristina Domingo, Matthias Niedrig, Gustavo Palacios, Omar Jabado, Noelia Reyes, Joaquim Gascon, Maria Cabrerizo, W I Lipkin, Antonio TenorioAbstract:Here we propose the use of a 216-nucleotide fragment located in the carboxyl terminus of the E gene (E-COOH) and a pairwise-based comparison method for genotyping of Dengue Virus 1 (DENV-1) strains. We have applied this method to the detection and characterization of DENV-1 in serum samples from travelers returning from the tropics. The results obtained with the typing system correlate with the results obtained by comparison of the sequences of the entire E gene of the strains. The approach demonstrates utility in plotting the distribution and circulation of different genotypes of DENV-1 and also suggests the presence of two new clades of Indian strains. The integration of the method with an online database and a typing characterization tool enhances its strength. Additionally, the analysis of the complete E gene of DENV-1 strains suggested the occurrence of a nondescribed recombination event in the China GD23-95 strain. We propose the use of this methodology as a tool for real-time epidemiological surveillance of Dengue Virus infections and their pathogenesis.
Marie Vazeille - One of the best experts on this subject based on the ideXlab platform.
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Experimental adaptation of Dengue Virus 1 to Aedes albopictus mosquitoes by in vivo selection
Scientific Reports, 2020Co-Authors: Rachel Bellone, Sebastian Lequime, Henri Jupille, Giel Göertz, Fabien Aubry, Laurence Mousson, Géraldine Piorkowski, Pei-shi Yen, Gaelle Gabiane, Marie VazeilleAbstract:In most of the world, Dengue Virus (DENV) is mainly transmitted by the mosquito Aedes aegypti while in Europe, Aedes albopictus is responsible for human DENV cases since 2010. Identifying mutations that make DENV more competent for transmission by Ae. albopictus will help to predict emergence of epidemic strains. Ten serial passages in vivo in Ae. albopictus led to select DENV-1 strains with greater infectivity for this vector in vivo and in cultured mosquito cells. These changes were mediated by multiple adaptive mutations in the Virus genome, including a mutation at position 10,418 in the DENV 3′UTR within an RNA stem-loop structure involved in subgenomic flaviVirus RNA production. Using reverse genetics, we showed that the 10,418 mutation alone does not confer a detectable increase in transmission efficiency in vivo. These results reveal the complex adaptive landscape of DENV transmission by mosquitoes and emphasize the role of epistasis in shaping evolutionary trajectories of DENV variants.
Bruno Guy - One of the best experts on this subject based on the ideXlab platform.
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characterization of recombinant yellow fever Dengue vaccine Viruses with human monoclonal antibodies targeting key conformational epitopes
Vaccine, 2019Co-Authors: Valerie Lecouturier, Nicholas Jackson, Catherine Berry, Aure Saulnier, Sophie Naville, Catherine Manin, Yves Girerdchambaz, James E Crowe, Bruno GuyAbstract:Abstract The recombinant yellow fever-17D–Dengue Virus, live, attenuated, tetravalent Dengue vaccine (CYD-TDV) is licensed in several Dengue-endemic countries. Although the vaccine provides protection against Dengue, the level of protection differs by serotype and warrants further investigation. We characterized the antigenic properties of each vaccine Virus serotype using highly neutralizing human monoclonal antibodies (hmAbs) that bind quaternary structure-dependent epitopes. Specifically, we monitored the binding of Dengue Virus-1 (DENV-1; 1F4), DENV-2 (2D22) or DENV-3 (5J7) serotype-specific or DENV-1–4 cross-reactive (1C19) hmAbs to the four chimeric yellow fever-Dengue vaccine Viruses (CYD-1–4) included in phase III vaccine formulations using a range of biochemical and functional assays (dot blot, ELISA, surface plasmon resonance and plaque reduction neutralization assays). In addition, we used the “classic” live, attenuated DENV-2 vaccine serotype, immature CYD-2 Viruses and DENV-2 Virus-like particles as control antigens for anti-serotype-2 reactivity. The CYD vaccine serotypes were recognized by each hmAbs with the expected specificity, moreover, surface plasmon resonance indicated a high functional affinity interaction with the CYD serotypes. In addition, the hmAbs provided similar protection against CYD and wild-type Dengue Viruses in the in vitro neutralization assay. Overall, these findings demonstrate that the four CYD Viruses used in clinical trials display key conformational and functional epitopes targeted by serotype-specific and/or cross-reactive neutralizing human antibodies. More specifically, we showed that CYD-2 displays serotype- specific epitopes present only on the mature Virus. This indicates that the CYD-TDV has the ability to elicit antibody specificities which are similar to those induced by the wild type DENV. Future investigations will be needed to address the nature of CYD-TDV-induced responses after vaccine administration, and how these laboratory markers relate to vaccine efficacy and safety.
Rachel Bellone - One of the best experts on this subject based on the ideXlab platform.
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Experimental adaptation of Dengue Virus 1 to Aedes albopictus mosquitoes by in vivo selection
Scientific Reports, 2020Co-Authors: Rachel Bellone, Sebastian Lequime, Henri Jupille, Giel Göertz, Fabien Aubry, Laurence Mousson, Géraldine Piorkowski, Pei-shi Yen, Gaelle Gabiane, Marie VazeilleAbstract:In most of the world, Dengue Virus (DENV) is mainly transmitted by the mosquito Aedes aegypti while in Europe, Aedes albopictus is responsible for human DENV cases since 2010. Identifying mutations that make DENV more competent for transmission by Ae. albopictus will help to predict emergence of epidemic strains. Ten serial passages in vivo in Ae. albopictus led to select DENV-1 strains with greater infectivity for this vector in vivo and in cultured mosquito cells. These changes were mediated by multiple adaptive mutations in the Virus genome, including a mutation at position 10,418 in the DENV 3′UTR within an RNA stem-loop structure involved in subgenomic flaviVirus RNA production. Using reverse genetics, we showed that the 10,418 mutation alone does not confer a detectable increase in transmission efficiency in vivo. These results reveal the complex adaptive landscape of DENV transmission by mosquitoes and emphasize the role of epistasis in shaping evolutionary trajectories of DENV variants.
Antonio Tenorio - One of the best experts on this subject based on the ideXlab platform.
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use of a short fragment of the c terminal e gene for detection and characterization of two new lineages of Dengue Virus 1 in india
Journal of Clinical Microbiology, 2006Co-Authors: Cristina Domingo, Matthias Niedrig, Gustavo Palacios, Omar Jabado, Noelia Reyes, Joaquim Gascon, Maria Cabrerizo, W I Lipkin, Antonio TenorioAbstract:Here we propose the use of a 216-nucleotide fragment located in the carboxyl terminus of the E gene (E-COOH) and a pairwise-based comparison method for genotyping of Dengue Virus 1 (DENV-1) strains. We have applied this method to the detection and characterization of DENV-1 in serum samples from travelers returning from the tropics. The results obtained with the typing system correlate with the results obtained by comparison of the sequences of the entire E gene of the strains. The approach demonstrates utility in plotting the distribution and circulation of different genotypes of DENV-1 and also suggests the presence of two new clades of Indian strains. The integration of the method with an online database and a typing characterization tool enhances its strength. Additionally, the analysis of the complete E gene of DENV-1 strains suggested the occurrence of a nondescribed recombination event in the China GD23-95 strain. We propose the use of this methodology as a tool for real-time epidemiological surveillance of Dengue Virus infections and their pathogenesis.