11 results on '"Laurent Audry"'
Search Results
2. A simplified 4-site economical intradermal post-exposure rabies vaccine regimen: a randomised controlled comparison with standard methods.
- Author
-
Mary J Warrell, Anna Riddell, Ly-Mee Yu, Judith Phipps, Linda Diggle, Hervé Bourhy, Jonathan J Deeks, Anthony R Fooks, Laurent Audry, Sharon M Brookes, François-Xavier Meslin, Richard Moxon, Andrew J Pollard, and David A Warrell
- Subjects
Arctic medicine. Tropical medicine ,RC955-962 ,Public aspects of medicine ,RA1-1270 - Abstract
The need for economical rabies post-exposure prophylaxis (PEP) is increasing in developing countries. Implementation of the two currently approved economical intradermal (ID) vaccine regimens is restricted due to confusion over different vaccines, regimens and dosages, lack of confidence in intradermal technique, and pharmaceutical regulations. We therefore compared a simplified 4-site economical PEP regimen with standard methods.Two hundred and fifty-four volunteers were randomly allocated to a single blind controlled trial. Each received purified vero cell rabies vaccine by one of four PEP regimens: the currently accepted 2-site ID; the 8-site regimen using 0.05 ml per ID site; a new 4-site ID regimen (on day 0, approximately 0.1 ml at 4 ID sites, using the whole 0.5 ml ampoule of vaccine; on day 7, 0.1 ml ID at 2 sites and at one site on days 28 and 90); or the standard 5-dose intramuscular regimen. All ID regimens required the same total amount of vaccine, 60% less than the intramuscular method. Neutralising antibody responses were measured five times over a year in 229 people, for whom complete data were available.All ID regimens showed similar immunogenicity. The intramuscular regimen gave the lowest geometric mean antibody titres. Using the rapid fluorescent focus inhibition test, some sera had unexpectedly high antibody levels that were not attributable to previous vaccination. The results were confirmed using the fluorescent antibody virus neutralisation method.This 4-site PEP regimen proved as immunogenic as current regimens, and has the advantages of requiring fewer clinic visits, being more practicable, and having a wider margin of safety, especially in inexperienced hands, than the 2-site regimen. It is more convenient than the 8-site method, and can be used economically with vaccines formulated in 1.0 or 0.5 ml ampoules. The 4-site regimen now meets all requirements of immunogenicity for PEP and can be introduced without further studies.Controlled-Trials.com ISRCTN 30087513.
- Published
- 2008
- Full Text
- View/download PDF
3. DMP PureMagRup
- Author
-
Laurent AUDRY, Mariette Matondo, Guy TRAN VAN NHIEU, and Jost Enninga
- Abstract
Data management plan concerning the ANR's project PureMagRup
- Published
- 2022
- Full Text
- View/download PDF
4. A simplified 4-site economical intradermal post-exposure rabies vaccine regimen: a randomised controlled comparison with standard methods
- Author
-
Ly-Mee Yu, Andrew J. Pollard, Laurent Audry, Sharon M. Brookes, David A. Warrell, François-Xavier Meslin, Judith Phipps, Linda Diggle, Richard Moxon, Anthony R. Fooks, Hervé Bourhy, Jonathan J Deeks, Mary J. Warrell, and Anna Riddell
- Subjects
Male ,medicine.medical_treatment ,0302 clinical medicine ,Rabies vaccine ,030212 general & internal medicine ,Virology/Vaccines ,Confusion ,Viral Vaccine ,lcsh:Public aspects of medicine ,Standard methods ,Middle Aged ,3. Good health ,Vaccinology ,Infectious Diseases ,Female ,medicine.symptom ,medicine.drug ,Research Article ,Infectious Diseases/Tropical and Travel-Associated Diseases ,Adult ,medicine.medical_specialty ,Post exposure ,lcsh:Arctic medicine. Tropical medicine ,Adolescent ,Injections, Intradermal ,lcsh:RC955-962 ,Rabies ,Immunology ,030231 tropical medicine ,Public Health and Epidemiology/Immunization ,03 medical and health sciences ,Young Adult ,Infectious Diseases/Viral Infections ,medicine ,Humans ,Post-exposure prophylaxis ,Intensive care medicine ,Neurological Disorders/Infectious Diseases of the Nervous System ,Infectious Diseases/Infectious Diseases of the Nervous System ,business.industry ,Public Health, Environmental and Occupational Health ,lcsh:RA1-1270 ,medicine.disease ,Regimen ,Infectious Diseases/Neglected Tropical Diseases ,Rabies Vaccines ,Public Health and Epidemiology/Preventive Medicine ,business - Abstract
Background The need for economical rabies post-exposure prophylaxis (PEP) is increasing in developing countries. Implementation of the two currently approved economical intradermal (ID) vaccine regimens is restricted due to confusion over different vaccines, regimens and dosages, lack of confidence in intradermal technique, and pharmaceutical regulations. We therefore compared a simplified 4-site economical PEP regimen with standard methods. Methods Two hundred and fifty-four volunteers were randomly allocated to a single blind controlled trial. Each received purified vero cell rabies vaccine by one of four PEP regimens: the currently accepted 2-site ID; the 8-site regimen using 0.05 ml per ID site; a new 4-site ID regimen (on day 0, approximately 0.1 ml at 4 ID sites, using the whole 0.5 ml ampoule of vaccine; on day 7, 0.1 ml ID at 2 sites and at one site on days 28 and 90); or the standard 5-dose intramuscular regimen. All ID regimens required the same total amount of vaccine, 60% less than the intramuscular method. Neutralising antibody responses were measured five times over a year in 229 people, for whom complete data were available. Findings All ID regimens showed similar immunogenicity. The intramuscular regimen gave the lowest geometric mean antibody titres. Using the rapid fluorescent focus inhibition test, some sera had unexpectedly high antibody levels that were not attributable to previous vaccination. The results were confirmed using the fluorescent antibody virus neutralisation method. Conclusions This 4-site PEP regimen proved as immunogenic as current regimens, and has the advantages of requiring fewer clinic visits, being more practicable, and having a wider margin of safety, especially in inexperienced hands, than the 2-site regimen. It is more convenient than the 8-site method, and can be used economically with vaccines formulated in 1.0 or 0.5 ml ampoules. The 4-site regimen now meets all requirements of immunogenicity for PEP and can be introduced without further studies. Trial Registration Controlled-Trials.com ISRCTN 30087513, Author Summary All human deaths from rabies result from failure to give adequate prophylaxis. After a rabid animal bite, immediate wound cleaning, rabies vaccine and immunoglobulin injections effectively prevent fatal infection. Immunoglobulin is very rarely available in developing countries, where prevention relies on efficacious vaccine. WHO approved vaccines are prohibitively expensive, but 2 economical regimens (injecting small amounts of vaccine intradermally, into the skin, at 2 or 8 sites on the first day of the course) have been used for many years in a few places. Practical or perceived difficulties have restricted widespread uptake of economical methods. These could largely be overcome by introducing a new, simpler regimen, involving 4 site injections on the first day. We vaccinated volunteers to compare the antibody levels induced by the 4-site intradermal regimen with those induced by the current 2-site and 8-site regimens and the “gold standard” intramuscular regimen favoured internationally. All the economical intradermal regimens were at least as immunogenic as the intramuscular method. The results provide sufficient evidence that the 4-site regimen meets the criteria necessary for its recommendation for use wherever the cost of vaccine is prohibitive and especially where 2 or more patients are treated on the same day.
- Published
- 2016
5. Visualizing the Translocation and Localization of Bacterial Type III Effector Proteins by Using a Genetically Encoded Reporter System
- Author
-
Paul Dean, Jayde A. Gawthorne, John M. Christie, Laurent Audry, Claire McQuitty, Jost Enninga, Andrew J. Roe, University of Glasgow, Institut Pasteur [Paris], Newcastle University [Newcastle], This study was supported by a grant from the BBSRC Tools and Development Fund (BB/H023518=/1) to A.J.R. and J.M.C. C.M. was supported under a BBSRC DTP studentship., and Institut Pasteur [Paris] (IP)
- Subjects
0301 basic medicine ,MESH: Shigella flexneri ,030106 microbiology ,Virulence ,Chromosomal translocation ,MESH: Escherichia coli Proteins ,Biology ,medicine.disease_cause ,Escherichia coli O157 ,Applied Microbiology and Biotechnology ,Type three secretion system ,Shigella flexneri ,03 medical and health sciences ,MESH: Type III Secretion Systems ,Bacterial Proteins ,Protein Domains ,Genes, Reporter ,[SDV.BC.IC]Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB] ,medicine ,Type III Secretion Systems ,Methods ,Humans ,[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM] ,Escherichia coli ,MESH: Bacterial Proteins ,Genetics ,Host cell membrane ,MESH: Optical Imaging ,MESH: Humans ,Ecology ,Effector ,C-terminus ,Escherichia coli Proteins ,Optical Imaging ,MESH: Genes, Reporter ,MESH: Host-Pathogen Interactions ,biology.organism_classification ,Cell biology ,030104 developmental biology ,MESH: Escherichia coli O157 ,Host-Pathogen Interactions ,MESH: HeLa Cells ,MESH: Protein Domains ,MESH: Genetic Engineering ,Genetic Engineering ,Food Science ,Biotechnology ,HeLa Cells - Abstract
Bacterial type III secretion system (T3SS) effector proteins are critical determinants of infection for many animal and plant pathogens. However, monitoring of the translocation and delivery of these important virulence determinants has proved to be technically challenging. Here, we used a genetically engineered LOV (light-oxygen-voltage) sensing domain derivative to monitor the expression, translocation, and localization of bacterial T3SS effectors. We found the Escherichia coli O157:H7 bacterial effector fusion Tir-LOV was functional following its translocation and localized to the host cell membrane in discrete foci, demonstrating that LOV-based reporters can be used to visualize the effector translocation with minimal manipulation and interference. Further evidence for the versatility of the reporter was demonstrated by fusing LOV to the C terminus of the Shigella flexneri effector IpaB. IpaB-LOV localized preferentially at bacterial poles before translocation. We observed the rapid translocation of IpaB-LOV in a T3SS-dependent manner into host cells, where it localized at the bacterial entry site within membrane ruffles.
- Published
- 2016
6. Serologic Evidence of Lyssavirus Infection in Bats, Cambodia
- Author
-
Laurent Audry, Jean-Marc Reynes, Sopheak Ngin, Joe Walston, Hervé Bourhy, Sophie Molia, Sotheara Hout, Institut Pasteur du Cambodge, Réseau International des Instituts Pasteur (RIIP), Institut Pasteur [Paris] (IP), Wildlife Conservation Society [Phnom Penh, Cambodia], Wildlife Conservation Society (WCS), and Institut Pasteur [Paris]
- Subjects
Epidemiology ,MESH: Lyssavirus ,lcsh:Medicine ,L73 - Maladies des animaux ,Antibodies, Viral ,Serology ,0302 clinical medicine ,Seroepidemiologic Studies ,[SDV.MHEP.MI]Life Sciences [q-bio]/Human health and pathology/Infectious diseases ,Chiroptera ,Immunologie ,MESH: Animals ,0303 health sciences ,[SDV.MHEP.ME]Life Sciences [q-bio]/Human health and pathology/Emerging diseases ,medicine.diagnostic_test ,MESH: Chiroptera ,dispatch ,3. Good health ,Épidémiologie ,Infectious Diseases ,[SDV.MP.VIR]Life Sciences [q-bio]/Microbiology and Parasitology/Virology ,Antibody ,Infection ,Cambodia ,Microbiology (medical) ,030231 tropical medicine ,bats ,Biology ,Immunofluorescence ,lcsh:Infectious and parasitic diseases ,03 medical and health sciences ,Rhabdoviridae Infections ,medicine ,Animals ,Surveillance épidémiologique ,lcsh:RC109-216 ,Lyssavirus ,030304 developmental biology ,MESH: Seroepidemiologic Studies ,MESH: Cambodia ,lcsh:R ,MESH: Rhabdoviridae Infections ,Serum samples ,biology.organism_classification ,Virology ,Lyssavirus infection ,biology.protein ,MESH: Antibodies, Viral ,[SDV.MHEP]Life Sciences [q-bio]/Human health and pathology - Abstract
International audience; In Cambodia, 1,303 bats of 16 species were tested for lyssavirus. No lyssavirus nucleocapsid was detected in 1,283 brains tested by immunofluorescence assay. Antibodies against lyssaviruses were detected by enzyme-linked immunosorbent assay in 144 (14.7%) of 981 serum samples. Thirty of 187 serum samples contained neutralizing antibodies against different lyssaviruses.
- Published
- 2004
7. Hierarchies of Host Factor Dynamics at the Entry Site of Shigella flexneri during Host Cell Invasion
- Author
-
Christophe Zimmer, Laurent Audry, Philippe J. Sansonetti, Jost Enninga, Ricardo Henriques, Cristina Rodrigues, Soudeh Ehsani, Guy Tran Van Nhieu, José Carlos Santos, Langlais, Laurence, Dynamique des Interactions Hôte-Pathogène - Dynamics of Host-Pathogen Interactions, Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), Universidade do Porto = University of Porto, Imagerie et Modélisation, Pathogénie Microbienne Moléculaire, Institut Pasteur [Paris] (IP)-Institut National de la Santé et de la Recherche Médicale (INSERM), Collège de France - Chaire Microbiologie et Maladies infectieuses, Collège de France (CdF (institution)), Centre interdisciplinaire de recherche en biologie (CIRB), Labex MemoLife, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Collège de France (CdF (institution))-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), S.E. was supported by a grant from the Fondation Schlumberger pour l'Education et la Recherche. J.C.S. and C.D.R. were the recipients of fellowships from the Portuguese Fundaçāo para a Ciência e Tecnologia, FCT (SFRH/BD/51006/2010 and SFRH/BPD/41004/2007, respectively). C.D.R. is presently a Marie Curie fellow, We thank C. Parsot, R. Tsien, J. Swanson, and A. M. Pendergast for providing us with plasmids and/or bacterial strains. We are particularly thankful to M. Lelek for support in the PALM experiments. We acknowledge the members of the PFID at the Institut Pasteur for excellent microscopy support., Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), Universidade do Porto, Institut Pasteur [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), Chaire Microbiologie et Maladies infectieuses, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Collège de France (CdF (institution))-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Collège de France (CdF (institution))-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)
- Subjects
Cytoplasm ,Time Factors ,MESH: Shigella flexneri ,Immunology ,Endocytic cycle ,MESH: Microscopy, Fluorescence ,Vacuole ,[SDV.BC.IC] Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB] ,Time-Lapse Imaging ,Microbiology ,MESH: Vacuoles ,Shigella flexneri ,03 medical and health sciences ,[SDV.BC.IC]Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB] ,MESH: Cytoskeleton ,Humans ,MESH: Time-Lapse Imaging ,[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM] ,Cytoskeleton ,[SDV.BBM.BC] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM] ,Actin ,030304 developmental biology ,Host factor ,0303 health sciences ,Cellular Microbiology: Pathogen-Host Cell Molecular Interactions ,MESH: Humans ,biology ,030306 microbiology ,MESH: Cytoplasm ,MESH: Time Factors ,MESH: Host-Pathogen Interactions ,Epithelial Cells ,biology.organism_classification ,Entry into host ,3. Good health ,Cell biology ,Infectious Diseases ,Microscopy, Fluorescence ,MESH: Epithelial Cells ,Host-Pathogen Interactions ,Vacuoles ,MESH: HeLa Cells ,Parasitology ,HeLa Cells - Abstract
Shigella flexneri , the causative agent of bacillary dysentery, induces massive cytoskeletal rearrangement, resulting in its entry into nonphagocytic epithelial cells. The bacterium-engulfing membrane ruffles are formed by polymerizing actin, a process activated through injected bacterial effectors that target host small GTPases and tyrosine kinases. Once inside the host cell, S. flexneri escapes from the endocytic vacuole within minutes to move intra- and intercellularly. We quantified the fluorescence signals from fluorescently tagged host factors that are recruited to the site of pathogen entry and vacuolar escape. Quantitative time lapse fluorescence imaging revealed simultaneous recruitment of polymerizing actin, small GTPases of the Rho family, and tyrosine kinases. In contrast, we found that actin surrounding the vacuole containing bacteria dispersed first from the disassembling membranes, whereas other host factors remained colocalized with the membrane remnants. Furthermore, we found that the disassembly of the membrane remnants took place rapidly, within minutes after bacterial release into the cytoplasm. Superresolution visualization of galectin 3 through photoactivated localization microscopy characterized these remnants as small, specular, patchy structures between 30 and 300 nm in diameter. Using our experimental setup to track the time course of infection, we identified the S. flexneri effector IpgB1 as an accelerator of the infection pace, specifically targeting the entry step, but not vacuolar progression or escape. Together, our studies show that bacterial entry into host cells follows precise kinetics and that this time course can be targeted by the pathogen.
- Published
- 2012
8. Ecology and evolution of rabies virus in Europe
- Author
-
Katariina Kulonen, Laurent Audry, Malgorzata Sadkowska-Todys, Hervé Bourhy, Noël Tordo, B. Kissi, Marcin Smreczak, Jan Zmudzinski, and Edward C. Holmes
- Subjects
Databases, Factual ,Biology ,medicine.disease_cause ,Virus ,Evolution, Molecular ,Dogs ,Viral Envelope Proteins ,Virology ,medicine ,Animals ,Humans ,Nucleocapsid ,Antigens, Viral ,Phylogeny ,Glycoproteins ,Phylogenetic tree ,Ecology ,Rabies virus ,Raccoon Dogs ,Sequence Analysis, DNA ,Nucleocapsid Proteins ,medicine.disease ,Adaptation, Physiological ,Nucleoprotein ,Europe ,Cats ,Biological dispersal ,Evolutionary ecology ,Rabies ,Cattle - Abstract
The evolution of rabies viruses of predominantly European origin was studied by comparing nucleotide sequences of the nucleoprotein and glycoprotein genes, and by typing isolates using RFLP. Phylogenetic analysis of the gene sequence data revealed a number of distinct groups, each associated with a particular geographical area. Such a pattern suggests that rabies virus has spread westwards and southwards across Europe during this century, but that physical barriers such as the Vistula river in Poland have enabled localized evolution. During this dispersal process, two species jumps took place – one into red foxes and another into raccoon dogs, although it is unclear whether virus strains are preferentially adapted to particular animal species or whether ecological forces explain the occurrence of the phylogenetic groups.
- Published
- 1999
9. Dynamics of rabies virus quasispecies during serial passages in heterologous hosts
- Author
-
Hervé Bourhy, A. Lavenu, Hassan Badrane, Laurent Audry, Noël Tordo, M. Brahimi, and B. Kissi
- Subjects
Nonsynonymous substitution ,DNA Mutational Analysis ,Viral quasispecies ,Biology ,medicine.disease_cause ,Cell Line ,Genetic Heterogeneity ,Mice ,Dogs ,Viral Envelope Proteins ,Serial passage ,Virology ,Cricetinae ,Consensus Sequence ,medicine ,Animals ,Mutation frequency ,Serial Passage ,Nucleocapsid ,Gene ,Antigens, Viral ,Glycoproteins ,Genetics ,Mutation ,Rabies virus ,Nucleocapsid Proteins ,Nucleoprotein ,Cats - Abstract
To understand the mutations and genetic rearrangements that allow rabies virus infections of new hosts and adaptation in nature, the quasispecies structure of the nucleoprotein and glycoprotein genes as well as two noncoding sequences of a rabies virus genome were determined. Gene sequences were obtained from the brain and from the salivary glands of the original host, a naturally infected European fox, and after serial passages in mice, dogs, cats and cell culture. A relative genetic stasis of the consensus sequences confirmed previous results about the stability of rabies virus. At the quasispecies level, the mutation frequency varies, in the following order: glycoprotein region (21·9×10−4 mutations per bp), noncoding sequence nucleoprotein–phosphoprotein region (7·2–7·9×10−4 mutations per bp) and nucleoprotein gene region (2·9–3·7×10−4 mutations per bp). These frequencies varied according to the number, type of heterologous passages and the genomic region considered. The shape of the quasispecies structure was dramatically modified by passages in mice, in which the mutation frequencies increased by 12–31×10−4 mutations per bp, depending on the region considered. Nonsynonymous mutations were preponderant particularly in the glycoprotein gene, stressing the importance of positive selection in the maintenance and fixation of substitutions. Two mechanisms of genomic evolution of the rabies virus quasispecies, while adapting to environmental changes, have been identified: a limited accumulation of mutations with no replacement of the original master sequence and a less frequent but rapid selective overgrowth of favoured variants.
- Published
- 1999
10. Macropinosomes are Key Players in Early Shigella Invasion and Vacuolar Escape in Epithelial Cells
- Author
-
Noelia Lopez-Montero, Nora Mellouk, Jost Enninga, Allon Weiner, Christine Schmitt, Célia Souque, Yuen-Yan Chang, Dynamique des Interactions Hôte-Pathogène - Dynamics of Host-Pathogen Interactions, Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), Microscopie Ultrastructurale (Plate-forme), This work was supported by the Institut Pasteur (PTR 460), by fellowships from the Pasteur-Weizmann Council, EMBO and the Fondation pour la Recherche Médicale (FRM) to AW, by a fellowship from the FRM to NM, by a L’Oreal fellowship to YC, by an EMBO short term fellowship to NM, by a grant from the Region Ile de France to JE (DIM-Malinf), JE is member of the LabEx consortium IBEID, and is supported by the Institut Pasteur CARNOT-MIE programme. JE also acknowledges support of an ERC starting grant (Rupteffects, Nr. 261166)., We wish to thank Katya Rechav and Michael Elbaum for support with FIB/SET performed at the Irving and Cherna Moscowitz Center for Nano and Bio-nano Imaging of the Weizmann Institute. We thank Stéphane Dallongeville for support with ICY, Alexander Rouvinski for help designing dextran experiments, Laurent Audry for experimental support and and José Vieira Dos Santos for help with illustration. We would like to thank John Rohde for support with the mutant library screens and Guy Tran Van Nhieu, Michael Elbaum, Patricia Bassereau and DIHP members for critical reading of this manuscript., ANR-10-LABX-0062,IBEID,Integrative Biology of Emerging Infectious Diseases(2010), European Project: 261166,EC:FP7:ERC,ERC-2010-StG_20091118,RUPTEFFECTS(2011), and Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
0301 basic medicine ,MESH: Shigella flexneri ,Glycobiology ,Vacuole ,medicine.disease_cause ,Pathology and Laboratory Medicine ,Biochemistry ,Shigella flexneri ,[SDV.BC.IC]Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB] ,Medicine and Health Sciences ,Image Processing, Computer-Assisted ,Shigella ,Biology (General) ,Glucans ,Microscopy ,biology ,Pinocytosis ,MESH: Image Processing, Computer-Assisted ,Cell biology ,Endocytic vesicle ,Medical Microbiology ,MESH: Epithelial Cells ,Host-Pathogen Interactions ,Pathogens ,Cellular Structures and Organelles ,Intracellular ,Research Article ,MESH: Microscopy ,MESH: Dysentery, Bacillary ,Endosome ,QH301-705.5 ,030106 microbiology ,Immunology ,Endosomes ,Research and Analysis Methods ,Microbiology ,MESH: Vacuoles ,03 medical and health sciences ,Polysaccharides ,Virology ,Genetics ,medicine ,Humans ,Vesicles ,[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM] ,Molecular Biology Techniques ,Microbial Pathogens ,Molecular Biology ,Dextran ,Dysentery, Bacillary ,Intracellular pathogens ,Molecular Biology Assays and Analysis Techniques ,MESH: Humans ,Bacteria ,Intracellular parasite ,MESH: Host-Pathogen Interactions ,Organisms ,Biology and Life Sciences ,Epithelial Cells ,Cell Biology ,RC581-607 ,biology.organism_classification ,MESH: Pinocytosis ,030104 developmental biology ,MESH: Endosomes ,Vacuoles ,Library screening ,Parasitology ,Bacterial pathogens ,Immunologic diseases. Allergy - Abstract
Intracellular pathogens include all viruses, many bacteria and parasites capable of invading and surviving within host cells. Key to survival is the subversion of host cell pathways by the pathogen for the purpose of propagation and evading the immune system. The intracellular bacterium Shigella flexneri, the causative agent of bacillary dysentery, invades host cells in a vacuole that is subsequently ruptured to allow growth of the pathogen within the host cytoplasm. S. flexneri invasion has been classically described as a macropinocytosis-like process, however the underlying details and the role of macropinosomes in the intracellular bacterial lifestyle have remained elusive. We applied dynamic imaging and advanced large volume correlative light electron microscopy (CLEM) to study the highly transient events of S. flexneri’s early invasion into host epithelial cells and elucidate some of its fundamental features. First, we demonstrate a clear distinction between two compartments formed during the first step of invasion: the bacterial containing vacuole and surrounding macropinosomes, often considered identical. Next, we report a functional link between macropinosomes and the process of vacuolar rupture, demonstrating that rupture timing is dependent on the availability of macropinosomes as well as the activity of the small GTPase Rab11 recruited directly to macropinosomes. We go on to reveal that the bacterial containing vacuole and macropinosomes come into direct contact at the onset of vacuolar rupture. Finally, we demonstrate that S. flexneri does not subvert pre-existing host endocytic vesicles during the invasion steps leading to vacuolar rupture, and propose that macropinosomes are the major compartment involved in these events. These results provide the basis for a new model of the early steps of S. flexneri epithelial cell invasion, establishing a different view of the enigmatic process of cytoplasmic access by invasive bacterial pathogens., Author Summary Shigella flexneri is an intracellular bacterial pathogen and the causative agent of bacillary dysentery. It possesses the ability to invade and propagate within human cells by injecting bacterial effector proteins directly into host cells. Shortly after entry within a vacuole, S. flexneri induces vacuolar rupture and escapes into the host cytosol via an unknown mechanism. Using large volume correlative light electron microscopy (CLEM) and dynamic microscopy we studied discrete and highly transient steps of S. flexneri early invasion in detail. We provide the first 3D high resolution view of the S. flexneri invasion site and of vacuolar rupture itself. We find that vesicles formed at the invasion site due to injected bacterial effectors, termed macropinosomes, are functionally involved in vacuolar rupture and come into direct contact with the bacterial containing vacuole during this process. This unique and surprising pathogenic strategy stands in stark contrast to other invasive pathogens that induce direct lysis of their surrounding vacuole via the action of destabilizing bacterial proteins.
- Published
- 2016
11. Lyssavirus Matrix Protein Induces Apoptosis by a TRAIL-Dependent Mechanism Involving Caspase-8 Activation
- Author
-
Hervé Bourhy, Jérôme Estaquier, Raid Kassis, Florence Larrous, Institut Pasteur [Paris] (IP), R.K. was supported by a predoctoral scholarship from the regional council of Guadeloupe, France., and We thank S. Susin for helpful discussions and suggestions. We are grateful to Laurent Audry and Rolande Rotsen for expert technical assistance. We thank Patricia Davis for critical comments.
- Subjects
Programmed cell death ,Immunology ,Apoptosis ,[SDV.BC]Life Sciences [q-bio]/Cellular Biology ,Cycloheximide ,Caspase 8 ,Microbiology ,Receptors, Tumor Necrosis Factor ,Fas ligand ,TNF-Related Apoptosis-Inducing Ligand ,Viral Matrix Proteins ,Mice ,Neuroblastoma ,chemistry.chemical_compound ,Virology ,Tumor Cells, Cultured ,Animals ,Humans ,Caspase ,Membrane Glycoproteins ,biology ,Tumor Necrosis Factor-alpha ,Transfection ,Virus-Cell Interactions ,Cell biology ,chemistry ,Caspases ,Insect Science ,biology.protein ,Lyssavirus ,Tumor necrosis factor alpha ,Apoptosis Regulatory Proteins ,HeLa Cells ,Signal Transduction - Abstract
Lyssaviruses, which are members of the Rhabdoviridae family, induce apoptosis, which plays an important role in the neuropathogenesis of rabies. However, the mechanisms by which these viruses mediate neuronal apoptosis have not been elucidated. Here we demonstrate that the early induction of apoptosis in a model of lyssavirus-infected neuroblastoma cells involves a TRAIL-dependent pathway requiring the activation of caspase-8 but not of caspase-9 or caspase-10. The activation of caspase-8 results in the activation of caspase-3 and caspase-6, as shown by an increase in the cleavage of the specific caspase substrate in lyssavirus-infected cells. However, neither caspase-1 nor caspase-2 activity was detected during the early phase of infection. Lyssavirus-mediated cell death involves an interaction between TRAIL receptors and TRAIL, as demonstrated by experiments using neutralizing antibodies and soluble decoy TRAIL-R1/R2 receptors. We also demonstrated that the decapsidation and replication of lyssavirus are essential for inducing apoptosis, as supported by UV inactivation, cycloheximide treatment, and the use of bafilomycin A1 to inhibit endosomal acidification. Transfection of cells with the matrix protein induced apoptosis using pathways similar to those described in the context of viral infection. Furthermore, our data suggest that the matrix protein of lyssaviruses plays a major role in the early induction of TRAIL-mediated apoptosis by the release of a soluble, active form of TRAIL. In our model, Fas ligand (CD95L) appears to play a limited role in lyssavirus-mediated neuroblastoma cell death. Similarly, tumor necrosis factor alpha does not appear to play an important role.
- Published
- 2004
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.