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Ivanov DG, Ivetic N, Du Y, Nguyen SN, Le SH, Favre D, Nazy I, Kaltashov IA. Reverse Engineering of a Pathogenic Antibody Reveals the Molecular Mechanism of Vaccine-Induced Immune Thrombotic Thrombocytopenia. J Am Chem Soc 2023; 145:25203-25213. [PMID: 37949820 DOI: 10.1021/jacs.3c07846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
The massive COVID-19 vaccine roll-out campaign illuminated a range of rare side effects, the most dangerous of which─vaccine-induced immune thrombotic thrombocytopenia (VITT)─is caused by adenoviral (Ad)-vectored vaccines. VITT occurrence had been linked to the production of pathogenic antibodies that recognize an endogenous chemokine, platelet factor 4 (PF4). Mass spectrometry (MS)-based evaluation of the ensemble of anti-PF4 antibodies obtained from a VITT patient's blood indicates that the major component is a monoclonal antibody. Structural characterization of this antibody reveals several unusual characteristics, such as the presence of an N-glycan in the Fab segment and high density of acidic amino acid residues in the complementarity-determining regions. A recombinant version of this antibody (RVT1) was generated by transient expression in mammalian cells based on the newly determined sequence. It captures the key properties of VITT antibodies such as their ability to activate platelets in a PF4 concentration-dependent fashion. Homology modeling of the Fab segment reveals a well-defined polyanionic paratope, and the docking studies indicate that the polycationic segment of PF4 readily accommodates two Fab segments, cross-linking the antibodies to yield polymerized immune complexes. Their existence was verified with native MS by detecting assemblies as large as (RVT1)3(PF4)2, pointing out at FcγRIIa-mediated platelet activation as the molecular mechanism underlying VITT clinical manifestations. In addition to the high PF4 affinity, RVT1 readily binds other polycationic targets, indicating a polyreactive nature of this antibody. This surprising promiscuity not only sheds light on VITT etiology but also opens up a range of opportunities to manage this pathology.
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Affiliation(s)
- Daniil G Ivanov
- Department of Chemistry, University of Massachusetts-Amherst, Amherst, Massachusetts 01003, United States
| | - Nikola Ivetic
- Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Yi Du
- Department of Chemistry, University of Massachusetts-Amherst, Amherst, Massachusetts 01003, United States
| | - Son N Nguyen
- Department of Chemistry, University of Massachusetts-Amherst, Amherst, Massachusetts 01003, United States
| | - S Hung Le
- Department of Chemistry, University of Massachusetts-Amherst, Amherst, Massachusetts 01003, United States
| | - Daniel Favre
- Department of Chemistry, University of Massachusetts-Amherst, Amherst, Massachusetts 01003, United States
| | - Ishac Nazy
- Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Igor A Kaltashov
- Department of Chemistry, University of Massachusetts-Amherst, Amherst, Massachusetts 01003, United States
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Favre D, Harmon JF, Zhang A, Miller MS, Kaltashov IA. Decavanadate interactions with the elements of the SARS-CoV-2 spike protein highlight the potential role of electrostatics in disrupting the infectivity cycle. J Inorg Biochem 2022; 234:111899. [PMID: 35716549 PMCID: PMC9183239 DOI: 10.1016/j.jinorgbio.2022.111899] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 06/02/2022] [Accepted: 06/05/2022] [Indexed: 12/15/2022]
Abstract
Polyoxidometalates (POMs) exhibit a range of biological properties that can be exploited for a variety of therapeutic applications. However, their potential utility as antivirals has been largely overlooked in the ongoing efforts to identify safe, effective and robust therapeutic agents to combat COVID-19. We focus on decavanadate (V10), a paradigmatic member of the POM family, to highlight the utility of electrostatic forces as a means of disrupting molecular processes underlying the SARS-CoV-2 entry into the host cell. While the departure from the traditional lock-and-key approach to the rational drug design relies on less-specific and longer-range interactions, it may enhance the robustness of therapeutic agents by making them less sensitive to the viral mutations. Native mass spectrometry (MS) not only demonstrates the ability of V10 to associate with the receptor-binding domain of the SARS-CoV-2 spike protein, but also provides evidence that this association disrupts the protein binding to its host cell-surface receptor. Furthermore, V10 is also shown to be capable of binding to the polybasic furin cleavage site within the spike protein, which is likely to decrease the effectiveness of the proteolytic processing of the latter (a pre-requisite for the viral fusion with the host cell membrane). Although in vitro studies carried out with SARS-CoV-2 infected cells identify V10 cytotoxicity as a major factor limiting its utility as an antiviral agent, the collected data provide a compelling stimulus for continuing the search for effective, robust and safe therapeutics targeting the novel coronavirus among members of the POM family.
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Affiliation(s)
- Daniel Favre
- Department of Chemistry, University of Massachusetts-Amherst, Amherst, MA 01003, United States of America
| | - Jackson F Harmon
- Institute for Applied Life Sciences, University of Massachusetts-Amherst, Amherst, MA 01003, United States of America
| | - Ali Zhang
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster Immunology Research Centre, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Matthew S Miller
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster Immunology Research Centre, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Igor A Kaltashov
- Department of Chemistry, University of Massachusetts-Amherst, Amherst, MA 01003, United States of America; Institute for Applied Life Sciences, University of Massachusetts-Amherst, Amherst, MA 01003, United States of America.
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Favre D, Bobst CE, Eyles SJ, Murakami H, Crans DC, Kaltashov IA. Solution- and gas-phase behavior of decavanadate: implications for mass spectrometric analysis of redox-active polyoxidometalates. Inorg Chem Front 2022; 9:1556-1564. [PMID: 35756945 PMCID: PMC9216222 DOI: 10.1039/d1qi01618k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This work explores the utility of high-resolution electrospray ionization (ESI) mass spectrometry (MS) and ion exclusion chromatography LC/MS for structural analysis of decavanadate (V10O286 ̄ or V10), a paradigmatic member...
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Affiliation(s)
- Daniel Favre
- Department of Chemistry, University of Massachusetts-Amherst, Amherst, MA
| | - Cedric E. Bobst
- Department of Chemistry, University of Massachusetts-Amherst, Amherst, MA
| | - Stephen J. Eyles
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, Amherst, MA
| | - Heide Murakami
- Department of Chemistry, Colorado State University, Ft. Collins, CO
| | - Debbie C. Crans
- Department of Chemistry, Colorado State University, Ft. Collins, CO
| | - Igor A. Kaltashov
- Department of Chemistry, University of Massachusetts-Amherst, Amherst, MA
- Corresponding Author: All correspondence should be addressed to Igor A. Kaltashov at
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Pantet O, Charrière M, Bagnoud G, Favre D, Schneider A, Viana M, Berger M. Organisational measures improve nutritional therapy in long stayer critically ill patients. Clin Nutr ESPEN 2020. [DOI: 10.1016/j.clnesp.2020.09.313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Bagnoud G, Charrière M, Favre D, Pantet O, Pichard C, Berger M. SUN-PO274: Validation Process of a New Calorimeter: Importance of a Mixing Chamber. Clin Nutr 2019. [DOI: 10.1016/s0261-5614(19)32904-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Sampey G, Irlbeck D, Browne E, Kanke M, Cule E, Wills S, Falcinelli S, Wang Z, Kircherr J, Allard B, Stuelke E, Sholtis K, Ferris R, Brehm J, Favre D, Routy JP, Jones C, Archin N, Margolis D, Dunham R. The SMAC mimetic AZD5582 reverses HIV latency as a single agent in resting primary CD4+ T cells. J Virus Erad 2019. [DOI: 10.1016/s2055-6640(20)31047-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Martinez A, Favre E, Kelevina T, Bagnoud G, Charrière M, Favre D, Pantet O, Berger M, Eckert P. Impact des soins infirmiers sur le suivi nutritionnel des patients inclus dans un programme dédié au « long séjour » : analyse de 120 patients de soins intensifs. NUTR CLIN METAB 2019. [DOI: 10.1016/j.nupar.2019.01.307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Bolla D, Favre D, Spinelli M, Baud D, Baumann M, Raio L. Placental anastomoses in monochorionic diamniotic twin pregnancy: not always a source of complication. Ultrasound Obstet Gynecol 2016; 48:253-254. [PMID: 26586033 DOI: 10.1002/uog.15822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 10/26/2015] [Accepted: 11/13/2015] [Indexed: 06/05/2023]
Affiliation(s)
- D Bolla
- Department of Obstetrics and Gynaecology, University Hospital of Bern, Bern, Switzerland
| | - D Favre
- Department of Obstetrics and Gynaecology, University Hospital of Bern, Bern, Switzerland
| | - M Spinelli
- Department of Obstetrics and Gynaecology, University Hospital of Bern, Bern, Switzerland
| | - D Baud
- Department of Obstetrics and Gynecology, University Hospital of Lausanne CHUV, Lausanne, Switzerland
- Swiss Fetal Laser Group. University Hospital of Bern, Bern, University Hospital of Lausanne CHUV, Lausanne, Switzerland
| | - M Baumann
- Department of Obstetrics and Gynaecology, University Hospital of Bern, Bern, Switzerland
| | - L Raio
- Department of Obstetrics and Gynaecology, University Hospital of Bern, Bern, Switzerland
- Swiss Fetal Laser Group. University Hospital of Bern, Bern, University Hospital of Lausanne CHUV, Lausanne, Switzerland
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Scheid E, Bergeron A, Dekaban G, Favre D, Eady R, O'Hoski P, Major P, Foley R. Vaccination with autologous dendritic cells pulsed with a MUC1 glycopeptide: a phase I/II study in castrate resistant non-metastatic prostate cancer patients. Cytotherapy 2013. [DOI: 10.1016/j.jcyt.2013.01.148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Caussidier C, El Hage F, Munoz F, Remki L, Larribi R, Khzami SE, Berger D, de Carvalho GS, Favre D. In search of a health education model: teachers' conceptions in four Mediterranean countries. Glob Health Promot 2011; 18:5-15. [PMID: 24803615 DOI: 10.1177/1757975911422962] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
School programs are defined to promote the health of the pupils and to develop their competencies so that they can adopt behaviors favorable to their health. With the European project FP6 Biohead-Citizen (2004-2007), we analyzed the conceptions of teachers as regards health education, in France, Lebanon, Morocco and Tunisia, in reference to the biomedical model and the social health model. These four countries were selected because their school curricula represented different models of health education. Lebanon and Tunisia addressed health education with the biomedical model. In Morocco, the curriculum was also primarily based on the biomedical model and enclosed a few instructions issued from the social health model. In France, the health education curriculum declared an approach based on the health promotion model. Our study was based on multivariate statistical analyses of questionnaires filled out by 2537 in-service and pre-service teachers. Our analysis showed that the conceptions of the teachers concerning health education were not structured and related to a specific model. We also found that the dominating factors of influence on the choices expressed with regards to health education were, among different sociocultural variables, the religion, the home country, and, to a lesser extent, the level of training. Thus, the conceptions of the teachers were not integrated into comprehensive approaches but related to individual characteristics. Consequently health education implementation would require thorough training for pre-service and in-service teachers and should also explicitly take into account their conceptions and values.
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Favre D, Niederhauser G, Fahmi D, Plaisance V, Brajkovic S, Beeler N, Allagnat F, Haefliger JA, Regazzi R, Waeber G, Abderrahmani A. Role for inducible cAMP early repressor in promoting pancreatic beta cell dysfunction evoked by oxidative stress in human and rat islets. Diabetologia 2011; 54:2337-46. [PMID: 21547497 PMCID: PMC3149674 DOI: 10.1007/s00125-011-2165-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 04/01/2011] [Indexed: 02/03/2023]
Abstract
AIMS/HYPOTHESIS Pro-atherogenic and pro-oxidant, oxidised LDL trigger adverse effects on pancreatic beta cells, possibly contributing to diabetes progression. Because oxidised LDL diminish the expression of genes regulated by the inducible cAMP early repressor (ICER), we investigated the involvement of this transcription factor and of oxidative stress in beta cell failure elicited by oxidised LDL. METHODS Isolated human and rat islets, and insulin-secreting cells were cultured with human native or oxidised LDL or with hydrogen peroxide. The expression of genes was determined by quantitative real-time PCR and western blotting. Insulin secretion was monitored by EIA kit. Cell apoptosis was determined by scoring cells displaying pycnotic nuclei. RESULTS Exposure of beta cell lines and islets to oxidised LDL, but not to native LDL raised the abundance of ICER. Induction of this repressor by the modified LDL compromised the expression of important beta cell genes, including insulin and anti-apoptotic islet brain 1, as well as of genes coding for key components of the secretory machinery. This led to hampering of insulin production and secretion, and of cell survival. Silencing of this transcription factor by RNA interference restored the expression of its target genes and alleviated beta cell dysfunction and death triggered by oxidised LDL. Induction of ICER was stimulated by oxidative stress, whereas antioxidant treatment with N-acetylcysteine or HDL prevented the rise of ICER elicited by oxidised LDL and restored beta cell functions. CONCLUSIONS/INTERPRETATION Induction of ICER links oxidative stress to beta cell failure caused by oxidised LDL and can be effectively abrogated by antioxidant treatment.
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Affiliation(s)
- D. Favre
- Service of Internal Medicine, CHUV-Hospital, Lausanne, Switzerland
- Department of Cell Biology and Morphology, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - G. Niederhauser
- Service of Internal Medicine, CHUV-Hospital, Lausanne, Switzerland
- Department of Cell Biology and Morphology, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - D. Fahmi
- Service of Internal Medicine, CHUV-Hospital, Lausanne, Switzerland
- Department of Cell Biology and Morphology, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - V. Plaisance
- Service of Internal Medicine, CHUV-Hospital, Lausanne, Switzerland
- Department of Cell Biology and Morphology, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - S. Brajkovic
- Service of Internal Medicine, CHUV-Hospital, Lausanne, Switzerland
- Department of Cell Biology and Morphology, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - N. Beeler
- Service of Internal Medicine, CHUV-Hospital, Lausanne, Switzerland
- Department of Cell Biology and Morphology, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - F. Allagnat
- Service of Internal Medicine, CHUV-Hospital, Lausanne, Switzerland
| | - J. A. Haefliger
- Service of Internal Medicine, CHUV-Hospital, Lausanne, Switzerland
| | - R. Regazzi
- Department of Cell Biology and Morphology, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - G. Waeber
- Service of Internal Medicine, CHUV-Hospital, Lausanne, Switzerland
| | - A. Abderrahmani
- Service of Internal Medicine, CHUV-Hospital, Lausanne, Switzerland
- Department of Cell Biology and Morphology, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
- CNRS-UMR-8199, Université Lille Nord de France, UDSL, Lille, France
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Favre D, Joly J, Reynaud C, Salvador LL. Empathie, contagion émotionnelle et coupure par rapport aux émotions : validation d’un test pour repérer et aider des élèves à risque. European Review of Applied Psychology 2009. [DOI: 10.1016/j.erap.2009.03.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Abstract
In hepadnaviruses, reverse transcription is primed by the viral reverse transcriptase (RT) and requires the specific interaction between the RT and the viral RNA encapsidation signal termed e. To study the activity of the RT in vitro, the current procedure uses in vitro translated duck hepatitis B virus polymerase, but not the hepatitis B virus polymerase itself, in the rabbit reticulocyte lysate expression system. Here, the hepatitis B virus (HBV) polymerase has been successfully expressed in a translational extract that was obtained from monolayer human hepatocyte cells HuH-7. The translated polypeptide retained the RNA-directed polymerase (reverse transcriptase) activity on the viral RNA template containing the e signal. We suggest that the reverse transcription event of the viral RNA coding for the polymerase and containing an e structure is concomitant to the translation of the viral polymerase to the messenger RNA. In contrast to the duck polymerase, only a fraction of the reverse transcribed complementary DNA (cDNA) was covalently bound to the HBV polymerase in this system. When the e signal was missing on the mRNA, the translated full-length HBV polymerase could not reverse transcribe the viral RNA template. A truncated HBV polymerase that was lacking the YMDD catalytic active site for the initiation of reverse transcription was unable to reverse transcribe the viral mRNA template containing the e signal. The reverse transcription activity could also be partially inhibited by employing nucleoside analogues, such as 2'-3'-dideoxy-3'-thiacytidine (3TC; lamivudine) in the expression system. The procedure described here provides a method for the in vitro screening of new anti-HBV compounds directed against wild- type and mutants of this crucial viral protein, the HBV polymerase, without the use of animals (ducks) or animal extracts (rabbit reticulocyte lysate).
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Ziethlow V, Favre D, Viret JF, Frey J, Stoffel M. Assessment by electron-microscopy of recombinant Vibrio cholerae and Salmonella vaccine strains expressing enterotoxigenic Escherichia coli-specific surface antigens. Clin Microbiol Infect 2008; 14:282-6. [DOI: 10.1111/j.1469-0691.2007.01908.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Favre D, Fausto N. Efficiency of hepatitis C virus infection in vitro. Am J Pathol 2007; 171:373; author reply 373. [PMID: 17591981 PMCID: PMC1941590 DOI: 10.2353/ajpath.2007.070352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abderrahmani A, Niederhauser G, Favre D, Abdelli S, Ferdaoussi M, Yang JY, Regazzi R, Widmann C, Waeber G. Human high-density lipoprotein particles prevent activation of the JNK pathway induced by human oxidised low-density lipoprotein particles in pancreatic beta cells. Diabetologia 2007; 50:1304-14. [PMID: 17437081 DOI: 10.1007/s00125-007-0642-z] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Accepted: 01/15/2007] [Indexed: 12/17/2022]
Abstract
AIMS/HYPOTHESIS We explored the potential adverse effects of pro-atherogenic oxidised LDL-cholesterol particles on beta cell function. MATERIALS AND METHODS Isolated human and rat islets and different insulin-secreting cell lines were incubated with human oxidised LDL with or without HDL particles. The insulin level was monitored by ELISA, real-time PCR and a rat insulin promoter construct linked to luciferase gene reporter. Cell apoptosis was determined by scoring cells displaying pycnotic nuclei. RESULTS Prolonged incubation with human oxidised LDL particles led to a reduction in preproinsulin expression levels, whereas the insulin level was preserved in the presence of native LDL-cholesterol. The loss of insulin production occurred at the transcriptional levels and was associated with an increase in activator protein-1 transcriptional activity. The rise in activator protein-1 activity resulted from activation of c-Jun N-terminal kinases (JNK, now known as mitogen-activated protein kinase 8 [MAPK8]) due to a subsequent decrease in islet-brain 1 (IB1; now known as MAPK8 interacting protein 1) levels. Consistent with the pro-apoptotic role of the JNK pathway, oxidised LDL also induced a twofold increase in the rate of beta cell apoptosis. Treatment of the cells with JNK inhibitor peptides or HDL countered the effects mediated by oxidised LDL. CONCLUSIONS/INTERPRETATION These data provide strong evidence that oxidised LDL particles exert deleterious effects in the progression of beta cell failure in diabetes and that these effects can be countered by HDL particles.
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Affiliation(s)
- A Abderrahmani
- Service of Internal Medicine, CHUV-Hospital, Rue du Bugnon 9, 1005 Lausanne, Switzerland.
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Vautrin J, Travo C, Boyer C, Ventéo S, Favre D, Dechesne CJ. Ocsyn and mitochondrial-canalicular complexes in vestibular hair cells. Hear Res 2006; 222:28-34. [PMID: 17045436 DOI: 10.1016/j.heares.2006.07.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Revised: 07/20/2006] [Accepted: 07/26/2006] [Indexed: 10/24/2022]
Abstract
Ocsyn, a syntaxin-interacting protein characterized by Safieddine et al. [Safieddine, S., Ly, C.D., Wang, Y.-X., Kachar, B., Petralia, R.S., Wenthold, R.J., 2002. Ocsyn, a novel syntaxin-interacting protein enriched in the subapical region of inner hair cells. Mol. Cell. Neurosci., 20, 343-353] in the guinea pig organ of Corti was primarily identified in organelles located at the subapical region of inner hair cells. They proposed that in cochlear inner hair cells, ocsyn was involved in protein trafficking associated to recycling endosomes. Ocsyn happens to be highly homologous to syntabulin with an almost identical syntaxin-binding domain. Syntabulin is believed to attach syntaxin-containing vesicles to kinesin for their axonal transport along microtubules. The present study shows the distribution of ocsyn in guinea pig and rat vestibular hair cells using immunocytochemistry and confocal microscopy. Ocsyn was characterized by intense immunolabeled spots distributed exclusively in type I and II vestibular hair cells. The subcuticular region under the cuticular plate exhibited particularly densely packed spots. In the neck region of the sensory cells, where microtubules are abundant, there was no colocalization of ocsyn and alpha-tubulin. Ocsyn labeled spots were also present in the medial and basal hair cell regions, particularly in the supranuclear and infranuclear regions. Mitochondria are particularly numerous in these three regions (subcuticular, supranuclear and infranuclear). Double labeling of ocsyn and cytochrome c showed that ocsyn was present in the same zones that mitochondria. This, together with the great similarity of ocsyn and syntabulin, suggest that, akin to syntabulin, ocsyn is involved in addressing organelles. We propose that ocsyn is involved in the formation of the canalicular-mitochondrial complexes depicted by Spicer et al. [Spicer, S.S., Thomopoulos, G.N., Schulte, B.A., 1999. Novel membranous structures in apical and basal compartments of inner hear cells. J. Comp. Neurol., 409, 424-437].
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Affiliation(s)
- Jean Vautrin
- INSERM U343, Université de Montpellier II, CC 103, Place Bataillon, 34095, Montpellier, cedex 5, France.
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Ludi S, Favre D, Frey J, Friess AE, Stoffel MH. Visualization of Surface-specific Antigens in Various Strains of Enterotoxigenic E. coli. Anat Histol Embryol 2005. [DOI: 10.1111/j.1439-0264.2005.00669_69.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Hepatitis C virus (HCV) infects hepatocytes and leads to permanent, severe liver damage. Since the genomic sequence of HCV was determined, progress has been made towards understanding the functions of the HCV-encoded proteins and identifying the cellular receptor(s) responsible for adsorption and penetration of the virus particle into the target cells. Several cellular receptors for HCV have been proposed, all of which are associated with lipid and lipoprotein metabolism. This article reviews the cellular receptors for HCV and suggests a general model for HCV entry into cells, in which lipoproteins play a crucial role.
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Affiliation(s)
- Daniel Favre
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University Hospital Zürich, Rämistrasse 100, CH-8091 Zürich, Switzerland
| | - Beat Muellhaupt
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University Hospital Zürich, Rämistrasse 100, CH-8091 Zürich, Switzerland
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Favre D, Muellhaupt B. Reactivation of creatine kinase by dithiothreitol prior to use in an in vitro translation extract. ALTEX 2005; 22:259-64. [PMID: 16344908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
BACKGROUND In vitro protein synthesis on exogenous messenger ribonucleic acids can be performed in various systems including cytoplasmic extract from eukaryotic cells, rabbit reticulocyte lysate and wheat germ extract. For optimal translation, an energy regeneration system based on creatine phosphate and creatine kinase is commonly employed for the regeneration of the endogenous adenosine triphosphate pools. Creatine kinase purchased from various commercial suppliers can be partially oxidised. Oxidised creatine kinase is not biologically active and might not allow the efficient initiation of translation of exogenous mRNAs in eukaryotic cell extracts in vitro. RESULTS We successfully used dithiothreitol to reduce and therefore reactivate commercially available creatine kinase. When employed in cytoplasmic extracts obtained from eukaryotic cells grown in monolayers, the reactivated creatine kinase restored translation of the exogenous mRNAs. CONCLUSION Lyophilised creatine kinase obtained from commercial suppliers can be purchased as an oxidised monomer. The reactivation of creatine kinase using a reducing agent such as dithiothreitol restores the biological activity of this enzyme. This procedure might therefore be extended to various other in vitro conditions and biological systems in which the maintenance of an efficient ATP-regenerating system is critical.
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Affiliation(s)
- Daniel Favre
- Division Gastroenterology and Hepatology, Department of Internal Medicine, University Hospital of Zurich, Switzerland.
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Favre D, Petit MA, Trépo C. Latent hepatitis B virus (HBV) infection and HBV DNA integration is associated with further transformation of hepatoma cells in vitro. ALTEX 2003; 20:131-42. [PMID: 12947486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
Hepatitis B virus (HBV) is the major cause of chronic liver disease and hepatocellular carcinoma in the world, with more than 400 million people infected worldwide. To date, there is no reliable model for the study of the many aspects of HBV infection, despite the use of the chimpanzee. Although several alternative methods have been previously developed for the in vitro study of HBV infection, there is still an urgent need for new in vitro infection models, including for the ability of HBV to integrate into the host cell genome. Here we describe a process to improve infection of the human hepatoma cell lines HepG2 and HuH-7 in vitro with HBV originating from human blood. As shown previously for infection of hepatocytes with hepatitis C virus (HCV), the removal of the cell-bound lipoproteins prior to the addition of the viral inoculum to the cells could also be critical for the uptake of HBV via lipoprotein (LDL)-related receptors. Induction by insulin and dexamethasone led to an increase of HBsAg expression at the cell surface in association with the integration of the viral DNA into the host genome and HBx RNA detection. This integration process was also shown to be associated with cytopathic changes and further phenotypic transformations of the cells.
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Affiliation(s)
- Daniel Favre
- INSERM, Virus des Hépatites et Pathologies Associées, F-Lyon.
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Favre D, Berthillon P, Trépo C. [In vitro hepatitis C. Elimination of lipoproteins associated with cells: an important stage to obtain an efficient infection of human hepatocytes by the hepatitis C virus]. Rev Med Suisse Romande 2002; 122:205. [PMID: 12071140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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Favre D, Berthillon P, Trépo C. Removal of cell-bound lipoproteins: a crucial step for the efficient infection of liver cells with hepatitis C virus in vitro. C R Acad Sci III 2001; 324:1141-8. [PMID: 11803815 DOI: 10.1016/s0764-4469(01)01397-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Hepatitis C virus (HCV) is of major social, medical and economic importance. The prevalence of HCV is approximatively 1% in most developed countries, and much higher in developing countries. HCV infection is the second major cause, after hepatitis B virus infection, for the generation of chronic liver disease and hepatocellular carcinoma. To date, the only reliable model for the study of HCV infection is the chimpanzee. Indeed, there is no robust in vitro infection system, yet. There is thus an urgent need for such an in vitro infection system in order to evaluate therapeutic agents. Here, a process is provided for infecting hepatocyte cell lines with hepatitis C virus in vitro. It is strongly suggested that cell-bound lipoproteins are playing a crucial role during the infection process. In order to obtain a robust infection, the cell-bound lipoproteins have first to be removed from their cellular receptor prior to the addition of viral inocula originating from human sera, the latter being made originally of a virus-lipoprotein complex.
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Affiliation(s)
- D Favre
- Institut national de la santé et de la recherche médicale, virus des hépatites, rétrovirus humains et pathologies associées, Inserm unité 271, 151, cours Albert Thomas, 69424 Lyon, France.
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26
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Favre D, Provost N, Blouin V, Blancho G, Chérel Y, Salvetti A, Moullier P. Immediate and long-term safety of recombinant adeno-associated virus injection into the nonhuman primate muscle. Mol Ther 2001; 4:559-66. [PMID: 11735340 DOI: 10.1006/mthe.2001.0494] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Previous studies on distribution and toxicity of viral vectors administered in monkeys indicated that the nonhuman primate model has a reasonable predictive value for clinical applications. In this study, eight macaques were injected intramuscularly with recombinant adeno-associated virus (rAAV) at doses similar to those administered to hemophilia B patients, and followed to analyze the dissemination and shedding in biological samples and long-term persistence in distant organs. Following rAAV delivery, we found vector genome in various biological fluids for up to 6 days and infectious particles exclusively in the serum during the first 48-72 hours. rAAV sequences were detected in peripheral blood mononuclear cells (PBMC) for up to 10 months. At necropsy, 8 to 18 months after rAAV delivery, rAAV sequences were found in lymph nodes and livers but never in the gonads. Tissue examination, of liver in particular, showed no abnormalities. We concluded that during our experimental time frame, rAAV-mediated gene transfer into skeletal muscle of macaques seemed to be safe with respect to the recipient and the environment. However, it was associated with a transient viremia and the persistence of rAAV sequences in PBMC, lymph nodes, and liver, the long-term consequences of which remain unknown.
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Affiliation(s)
- D Favre
- Laboratoire de Thérapie Génique, INSERM ERM-0105, CHU-Hotel DIEU, Bât. J. Monnet, 30 Avenue J. Monnet, 44035 Nantes Cedex 01, France
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Favre D, Trepo C. Translational extracts active biologically in vitro obtained from eukaryotic monolayer cells: a versatile method for viral RNA studies. J Virol Methods 2001; 92:177-81. [PMID: 11226564 DOI: 10.1016/s0166-0934(00)00285-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Preservation of enzymatic activities in biological samples, especially after freeze/thawing, is a crucial requirement in virological research. Theoretically, this preservation can be achieved with the presence of cryopreservative agents. In contrast to tedious methods, it was found that this might be readily achieved by using well-defined conditions, including sucrose in the samples. Hence, the generation of a translational extract obtained from eukaryotic cells that have grown as monolayers is described below. This versatile method could be used advantageously for the in vitro translation of messenger RNAs, added exogenously, including viral mRNAs. The translational extract can be prepared freshly on a daily basis, or more conveniently it can be frozen and thawed subsequently for further use, without loss of activity. It can replace the Krebs ascites fluid and the commercial rabbit reticulocyte lysate. The procedure employed for the preservation of the biological activity of the translational extract can be extended to various other biological samples.
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Affiliation(s)
- D Favre
- Unité de Recherche sur les Virus des Hépatites, Institut National de la Santé et de la Recherche Médicale, Unité 271, 151 Cours Albert-Thomas, 69003, Lyon, France.
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Favre D. Generation of a Translational Extract from Eukaryotic Cells that have Grown as Monolayers. ALTEX 2001; 14:107-110. [PMID: 11178495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
The present article relates to the rapid and efficient generation of an in vitro translational extract that is obtained from the cytoplasmic fraction of eukaryotic cells that have grown as monolayers. The procedure is totally devoid of the use of animals or animal fluids. The cytoplasmic extract that is obtained allows efficient protein synthesis of exogenously added mRNAs. The latter mRNAs can be purified from prokaryotic or eukaryotic cells, or can be transcribed in vitro by employing any convenient RNA polymerase (for example, the bacteriophage SP6, T3 or T7 RNA polymerase). The described cytoplasmic preparation appears to be applicable to a large number of different eukaryotic cell lines. The cytoplasmic extract can be prepared freshly on a daily basis, or can be frozen and subsequently thawed for further use, without loss of activity. The preparation of the translation extract does not require living animals.
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Favre D, Ferry N, Moullier P. Critical aspects of viral vectors for gene transfer into the kidney. J Am Soc Nephrol 2000; 11 Suppl 16:S149-53. [PMID: 11065348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
Viral vectors have been used in vitro and in vivo for more than a decade, with some significant results in specific situations, e.g., when recombinant adeno-associated virus is used for the long-term transduction of skeletal muscle in coagulation factor IX-deficient patients. However, the kidney has been quite difficult to transduce with any viral vector currently available. When viral transduction occurs, it is often heterogeneous, transient, and eventually associated with immune and toxic side effects. However, recombinant adeno-associated virus and lentiviral vectors remain to be fully evaluated in the kidney; the former is small enough to be filtered through the glomerular basement membrane. This may be critical, because glomerular filtration is required for DNA complex-mediated transduction of tubular cells. An alternative to in situ renal gene transfer is secretion of a therapeutic protein from a distant site, such as skeletal muscle. Several examples provide evidence that this could be a clinically relevant approach. It also may allow accurate determination of the pathophysiologic mechanisms involved in the establishment and maintenance of experimental glomerulonephritis.
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Affiliation(s)
- D Favre
- Gene Therapy Laboratory, CHU Hotel-Dieu, Nantes, France
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30
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Favre D, Cherel Y, Provost N, Blouin V, Ferry N, Moullier P, Salvetti A. Hyaluronidase enhances recombinant adeno-associated virus (rAAV)-mediated gene transfer in the rat skeletal muscle. Gene Ther 2000; 7:1417-20. [PMID: 10981669 DOI: 10.1038/sj.gt.3301256] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Skeletal muscle is a privileged target for long-term rAAV-mediated gene transfer in mouse, rat, dog and non-human primates. Intramuscular injections of rAAV encoding human factor IX in hemophilia B patients have been initiated, based on promising results gathered in affected dogs. We found that intramuscular rAAV administration in rats resulted in restricted transduction essentially along the myofibers axis with poor lateral diffusion. This suggested that the transduction rate might be limited by the ability of the virus to reach sites distant from the injection point. We tested whether hyaluronidase, an enzyme which dissociates the extracellular matrix, could enhance vector diffusion when injected in the rat muscle before administration of rAAV encoding either nuclear-localized beta-galactosidase (rAAVCMVnlsLacZ) or the human alpha-1-antitrypsin (rAAVCMVhAAT) under the control of the cytomegalovirus immediate--early promoter (CMV). The results showed that pretreatment of the rat anterior tibialis muscle with hyaluronidase resulted in: (1) a larger diffusion of the virus indicated by an increase in the area containing LacZ-transduced fibers, and (2) a two- to three-fold increase of transduction efficiency measured by the number of LacZ-positive fibers or by the hAAT serum concentration. We also provide evidence that hyaluronidase was well tolerated and was not associated with short- or long-term toxicity evaluated by morphological studies. Finally, in our experimental conditions, hyaluronidase did not promote rAAV dissemination to other organs as assessed by PCR to detect vector sequences. We conclude that pretreatment of skeletal muscle by hyaluronidase, a clinically available reagent, was harmless and resulted in a consistent and significant increase in rAAV diffusion and transduction levels.
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Affiliation(s)
- D Favre
- Laboratoire de Thérapie Génique, CHU Hôtel-Dieu, Nantes, France
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31
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Chadeuf G, Favre D, Tessier J, Provost N, Nony P, Kleinschmidt J, Moullier P, Salvetti A. Efficient recombinant adeno-associated virus production by a stable rep-cap HeLa cell line correlates with adenovirus-induced amplification of the integrated rep-cap genome. J Gene Med 2000; 2:260-8. [PMID: 10953917 DOI: 10.1002/1521-2254(200007/08)2:4<260::aid-jgm111>3.0.co;2-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND A possible procedure for the production of clinical grade recombinant adeno-associated virus type 2 (rAAV) would include the use of packaging cell lines, harboring the rep-cap genes and the vector, combined with a replication defective adenoviral plasmid to provide the helper activities. Several studies have already shown that rAAV can be efficiently assembled by infecting the stable packaging cell line with adenovirus. However, the direct comparison with an adenoviral plasmid has never been reported. METHODS To investigate this point, a clone of HeLa and 293 cells harboring one to two rep-cap copies per cell genome (HeRC32 and 293RC21, respectively) were generated. Recombinant AAV was produced by transiently transfecting the AAVCMVLacZ vector and supplying the adenoviral helper activities by either wild-type adenovirus or an adenoviral plasmid (pAdc). As a control, rAAV was similarly produced from naive Hela and 293 cells additionally transfected with a rep-cap plasmid. RESULTS Despite satisfactory rAAV yields from Hela and 293 cells, we show that those from HeRC32 and 293RC21 cells dramatically decrease when adenovirus is replaced by the adenoviral plasmid (pAdc). The analysis performed to identify the factors hampering efficient rAAV assembly by HeRC32 cells in the presence of pAdc shows that: (1) while upon adenovirus infection the integrated rep-cap genome undergoes a dramatic amplification leading to a 100-fold increase in the rep-cap copy number, no amplification is detected upon transfection of pAdc; (2) in pAdc-transfected HeRC32 cells, the intracellular localization of the adenovirus E4orf6 and E1B-55kDa proteins is abnormal as compared to adenovirus-infected cells. CONCLUSIONS This study documents that stable rep-cap cells lines are severely hampered for rAAV assembly when a replicative adenovirus is substituted with an adenoviral plasmid. Furthermore, our results also suggest that the lack of amplification of the rep-cap genes, eventually combined with the altered distribution of the adenoviral proteins, E4orf6 and E1B-55kDa, is related to the low rAAV yields observed under these conditions.
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Affiliation(s)
- G Chadeuf
- Laboratoire de Thérapie Génique, CHU Hotel-DIEU, Nantes, France
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32
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Affiliation(s)
- D Favre
- Molecular Biology Department, Swiss Serum and Vaccine Institute, Bern, Switzerland.
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Viret JF, Favre D, Wegmüller B, Herzog C, Que JU, Cryz SJ, Lang AB. Mucosal and systemic immune responses in humans after primary and booster immunizations with orally administered invasive and noninvasive live attenuated bacteria. Infect Immun 1999; 67:3680-5. [PMID: 10377160 PMCID: PMC116565 DOI: 10.1128/iai.67.7.3680-3685.1999] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mucosal and systemic immune responses after primary and booster immunizations with two attenuated live oral vaccine strains derived from a noninvasive (Vibrio cholerae) and an invasive (Salmonella typhi) enteric pathogen were comparatively evaluated. Vaccination with S. typhi Ty21a elicited antibody-secreting cell (ASC) responses specific for S. typhi O9, 12 lipopolysaccharide (LPS), as well as significant increases in levels of immunoglobulin G (IgG) and IgA antibodies to the same antigen in serum. A strong systemic CD4(+) T-helper type 1 cell-mediated immune (CMI) response was also induced. In contrast to results with Ty21a, no evidence of a CMI response was obtained after primary immunization with V. cholerae CVD 103-HgR in spite of the good immunogenicity of the vaccine. Volunteers who received a single dose of CVD 103-HgR primarily developed an IgM ASC response against whole vaccine cells and purified V. cholerae Inaba LPS, and seroconversion of serum vibriocidal antibodies occurred in four of five subjects. Serum IgG anti-cholera toxin antibody titers were of lower magnitude. For both live vaccines, the volunteers still presented significant local immunity 14 months after primary immunization, as revealed by the elevated baseline antibody titers at the time of the booster immunization and the lower ASC, serum IgG, and vibriocidal antibody responses after the booster immunization. These results suggest that local immunity may interfere with colonization of the gut by both vaccine strains at least up to 14 months after basis immunization. Interestingly, despite a low secondary ASC response, Ty21a was able to boost both humoral (anti-LPS systemic IgG and IgA) and CMI responses. Evidence of a CMI response was also observed for one of three volunteers given a cholera vaccine booster dose. The direct comparison of results with two attenuated live oral vaccine strains in human volunteers clearly showed that the capacity of the vaccine strain to colonize specific body compartments conditions the pattern of vaccine-induced immune responses.
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Affiliation(s)
- J F Viret
- Swiss Serum and Vaccine Institute Berne, Bern, Switzerland
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Rom E, Kim HC, Gingras AC, Marcotrigiano J, Favre D, Olsen H, Burley SK, Sonenberg N. Cloning and characterization of 4EHP, a novel mammalian eIF4E-related cap-binding protein. J Biol Chem 1998; 273:13104-9. [PMID: 9582349 DOI: 10.1074/jbc.273.21.13104] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
All eukaryotic mRNAs (except organellar) are capped at their 5' end. The cap structure (m7GpppN, where N is any nucleotide) is extremely important for the processing and translation of mRNA. Several cap-binding proteins that facilitate these processes have been characterized. Here we describe a novel human cytoplasmic protein that is 30% identical and 60% similar to the human translation initiation factor 4E (eIF4E). We demonstrate that this protein, named 4E Homologous Protein (4EHP), binds specifically to capped RNA in an ATP- and divalent ion-independent manner. The three-dimensional structure of 4EHP, as predicted by homology modeling, closely resembles that of eIF4E and site-directed mutagenesis analysis of 4EHP strongly suggests that it shares with eIF4E a common mechanism for cap binding. A putative function for 4EHP is discussed.
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Affiliation(s)
- E Rom
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada H3G1Y6
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Salvetti A, Orève S, Chadeuf G, Favre D, Cherel Y, Champion-Arnaud P, David-Ameline J, Moullier P. Factors influencing recombinant adeno-associated virus production. Hum Gene Ther 1998; 9:695-706. [PMID: 9551617 DOI: 10.1089/hum.1998.9.5-695] [Citation(s) in RCA: 205] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Recombinant adeno-associated virus (rAAV) is produced by transfecting cells with two constructs: the rAAV vector plasmid and the rep-cap plasmid. After subsequent adenoviral infection, needed for rAAV replication and assembly, the virus is purified from total cell lysates through CsCl gradients. Because this is a long and complex procedure, the precise titration of rAAV stocks, as well as the measure of the level of contamination with adenovirus and rep-positive AAV, are essential to evaluate the transduction efficiency of these vectors in vitro and in vivo. Our vector core is in charge of producing rAAV for outside investigators as part of a national network promoted by the Association Française contre les Myopathies/Généthon. We report here the characterization of 18 large-scale rAAV stocks produced during the past year. Three major improvements were introduced and combined in the rAAV production procedure: (i) the titration and characterization of rAAV stocks using a stable rep-cap HeLa cell line in a modified Replication Center Assay (RCA); (ii) the use of different rep-cap constructs to provide AAV regulatory and structural proteins; (iii) the use of an adenoviral plasmid to provide helper functions needed for rAAV replication and assembly. Our results indicate that: (i) rAAV yields ranged between 10(11) to 5 x 10(12) total particles; (ii) the physical particle to infectious particle (measured by RCA) ratios were consistently below 50 when using a rep-cap plasmid harboring an ITR-deleted AAV genome; the physical particle to transducing particle ratios ranged between 400 and 600; (iii) the use of an adenoviral plasmid instead of an infectious virion did not affect the particles or the infectious particles yields nor the above ratio. Most of large-scale rAAV stocks (7/9) produced using this plasmid were free of detectable infectious adenovirus as determined by RCA; (iv) all the rAAV stocks were contaminated with rep-positive AAV as detected by RCA. In summary, this study describes a general method to titrate rAAV, independently of the transgene and its expression, and to measure the level of contamination with adenovirus and rep-positive AAV. Furthermore, we report a new production procedure using adenoviral plasmids instead of virions and resulting in rAAV stocks with undetectable adenovirus contamination.
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Affiliation(s)
- A Salvetti
- Laboratoire de Thérapie Génique, CHU Hotel-DIEU, Nantes, France
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Gatto F, Favre D. [Use of discursive indicators to optimize the effects of physiotherapy in patients with lumbago]. Sante Publique 1997; 9:341-60. [PMID: 9490230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In physiotherapy, a new approach using epistemological devices related to the therapists language has been experimented during therapeutic consultations. Would this approach lead to an improvement of therapeutic results? Regarding this question, we have compared the therapeutic results obtained in two different groups of twenty patients suffering from lumbago. In one group, traditional methods have been used, while the patients in the other group take benefit from the use of "epistemological indicators", in order to explain our knowledge of this pathology. The results suggest that the pain felt by the patients and their body dysfunctions could partly be due to their lack of knowledge and understanding of as well as to their lack of action on, their pathology. In order to make use of a new or more applicable kind of knowledge, it seems necessary for the patients to give up some of their usual mental representations of the pathology.
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Affiliation(s)
- F Gatto
- Laboratoire de modélisation de la relation pédagogique, Université des Sciences, Montpellier
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Favre D, Studer E, Michel MR. Semliki Forest virus capsid protein inhibits the initiation of translation by upregulating the double-stranded RNA-activated protein kinase (PKR). Biosci Rep 1996; 16:485-511. [PMID: 9062700 DOI: 10.1007/bf01198464] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We investigated the possible translational role which elevated concentrations of highly purified Semliki Forest virus (SFV) capsid (C)-protein molecules may play in a cell-free translation system. Here we demonstrate that in the absence of double-stranded RNA high concentrations of C protein triggered the phosphorylation of the interferon-induced, double-stranded RNA-activated protein kinase, PKR. Activated PKR in turn phosphorylated its natural substrate, the alpha subunit of eukaryotic initiation factor 2 (eIF-2), thereby inhibiting initiation of host cell translation. These findings were further strengthened by experiments showing that during natural infection with SFV the maximum phosphorylation of PKR coincided with the maximum synthesis of C protein 4-9 hours post infection. Thus, our results demonstrate that high concentrations of C-protein molecules may act in a hitherto novel mechanism on PKR to inhibit host cell protein synthesis during viral infection.
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Affiliation(s)
- D Favre
- Institute of Medical Microbiology, University of Berne, Switzerland
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Abstract
A series of cosmid vectors, termed pSSVI215, pSSVI216-1, pSSVI216-2, pSSVI217, and pSSVI218, were constructed in order to facilitate the downstream processing of large inserts. Each vector has dual cos sites as well as a kanamycin resistance (KmR) gene flanked by recognition sites for the very rare cutter I-SceI meganuclease as well as symmetrical NotI and SwaI sites (SCEKAN cassette). Several unique cloning sites, including BamHI, are present on one side of the cassette between the I-SceI and NotI/SwaI sites. The various cosmids differ from each other by one or more of the following features: origin of replication (ori), size, host range, and conjugal transfer capability. Inserts combined with the SCEKAN cassette can be isolated on a NotI or SwaI fragment from any of these vectors and easily subcloned into the vector of choice by selecting for the adjacent KmR gene which can later be removed by I-SceI restriction and self-ligation. In addition, the SCEKAN cassette can be conveniently excised from plasmid pSSVI214 such that any plasmid can easily be fitted with the present system. The subcloning strategy afforded by the new vectors was successfully applied to an approximately 37-kb fragment from the V. cholerae O139 genome carrying the rfb locus which encodes the O-serotype specificity of this organism.
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Affiliation(s)
- D Favre
- Swiss Serum and Vaccine Institute, Bern, Switzerland
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Abstract
The rfb region from Vibrio cholerae O139 strain MO45 was cloned from cosmid gene banks established in Escherichia coli HB101, using an immunoblot assay for screening of the correct clones. Immunoblot analysis of lipopolysaccharide (LPS) preparations revealed the presence of two types of positive clones: (i) those expressing only a short core-linked O polysaccharide (SOPS) and (ii) those also expressing a highly polymerized capsular polysaccharide (CPS) not bound to the E. coli K-12 LPS core. In addition, the latter clones appear to contain a locus which may encode a putative regulator of SOPS and CPS chain length. Further characterization in E. coli showed that CPS constitutes a barrier against large particles such as the bacteriophage Ffm but not against bacteriophage lambda or P1. In addition, a portion of the K-12 LPS core may not be substituted with SOPS. Loci associated with the two clonal types were transferred into V. cholerae CH19, an rfbAB deletion mutant of CVD103-HgR deficient in the production of the homologous Inaba O polysaccharide. This resulted in the stable expression of SOPS, alone or together with CPS, that was indistinguishable from that of wild-type V. cholerae O139. Strains CH25 and CH26, which correspond to CH19 bearing the V. cholerae O139 rfb region integrated into the chromosome, were found to be genetically stable and essentially identical to the parent CVD103-HgR with respect to physiological properties such as cell motility, mercury resistance, toxicity, and production of the cholera toxin B subunit. Rabbits immunized with CH25 elicited high titers of anti-O139 SOPS- and CPS-specific serum antibodies. These strains possess characteristics desirable in candidate live oral vaccines against V. cholerae O139.
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Affiliation(s)
- D Favre
- Swiss Serum and Vaccine Institute, Berne, Switzerland
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Abstract
Vibrio cholerae CVD103-HgR, the first live attenuated vaccine licensed for human use produced by recombinant DNA technology, was genetically compared to its parent strains 569B and CVD103. The genetic stability for both lyophilized vaccine in final container form and for viable organisms shed from vaccinees was determined. Results obtained lead us to conclude: (i) the genetic composition of the examined genes in CVD103-HgR is identical to that of the parent strains except for the alterations induced; (ii) the level of mercury resistance depends on the orientation of the mer operon within hlyA, with the highest level being observed for the orientation found in CVD103-HgR; (iii) no DNA sequences from plasmids used in construction remain in the genome; (iv) the strain is genetically stable; and (v) both CVD103-HgR and its parent strains contain defective lysogenic prophages. We have further confirmed that a certain amount of restriction fragment length polymorphism (RFLP) exists around the chromosomal ctx locus within V. cholerae strains of the classical biotype (detectable on chromosomal DNA restricted by either HindIII or EcoRI, but not PstI).
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Affiliation(s)
- D Favre
- Swiss Serum and Vaccine Institute, Berne, Switzerland
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42
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Abstract
Making use of a newly designed mobilizable suicide vector, the genetic determinants encoding Shigella sonnei lipopolysaccharide (LPS) were stably integrated into the chromosome of the live attenuated Vibrio cholerae vaccine strain CVD103-HgR. Expression studies showed that the production of complete S. sonnei O-polysaccharide (O-PS)-bearing LPS was limited in bivalent recombinant strains that were also proficient in the synthesis of the host-encoded Inaba O-PS. Conversely, high amounts of LPS carrying S. sonnei O-PS are produced in monovalent Inaba-deficient derivatives, even in those strains which do not co-express the compatible R1 LPS core. Thus, the non-enterobacterial V. cholerae LPS core efficiently acts as a receptor for covalent binding of S. sonnei O-PS provided that competition with the host O-PS is avoided. Expression of the R1 core interferes with cell division in recombinant V. cholerae without affecting other physiological properties of vaccine strain CVD103-HgR. Both monovalent and bivalent strains stimulated high serum-antibody titres specific for their respective O-serotype(s) when administered to rabbits. The potential of V. cholerae as an expression carrier for heterologous O-serotypes is discussed.
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Affiliation(s)
- J F Viret
- Swiss Serum and Vaccine Institute, Berne, Switzerland
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43
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Favre D, Cryz SJ, Viret JF. Development of Shigella sonnei live oral vaccines based on defined rfbInaba deletion mutants of Vibrio cholerae expressing the Shigella serotype D O polysaccharide. Infect Immun 1996; 64:576-84. [PMID: 8550210 PMCID: PMC173804 DOI: 10.1128/iai.64.2.576-584.1996] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Previous experimentation has highlighted a number of difficulties in the development of carrier-based bivalent vaccines (J.-F. Viret and D. Favre, Biologicals 22:361-372, 1994) In an attempt to obviate these carrier strains. Toward this aim, a series of defined rfbInaba deletion (delta rfbInaba) mutants of the cholera vaccine strain V. cholerae CVD103-HgR (O1 Inaba serotype) and derivative bearing the chromosomally integrated locus encoding the S. sonnei O-PS were constructed and characterized. The various mutations disrupt genes thought to be involved in either the synthesis of perosamine, the synthesis of 3-deoxy-L-glycero tetronic acid, or the O-PS transport functions together with synthesis of the perosamine synthetase. Some deletions were obtained only in strains expressing the heterologous lipopolysaccharide (LPS). Viable delta rfbInaba deletions in CVD103-HgR profoundly altered some of its phenotypic properties. The same deletions present in CVD103-HgR derivatives expressing the heterologous LPS affected their phenotypes only to a lesser extent. Only in strains in which perosamine synthesis was specifically abolished could high amounts of core-bound S. sonnei O-PS be synthesized. Two such strains (CH21, which expresses both the R1 core and the S. sonnei O-PS, and CH22, which expresses only the latter antigenic determinant) were further analyzed and were found to be indistinguishable from CVD103-HgR with regard to lack of enterotoxin activity, choleragenoid production, mercury resistance, pilin production, and, for CH22, motility. Mice immunized with CH22 produced high titers of S. sonnei O-PS-specific antibodies.
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Affiliation(s)
- D Favre
- Swiss Serum and Vaccine Institute, Bern, Switzerland
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44
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Viret JF, Favre D. Bivalent vaccines against bacterial enteropathogens: construction of live attenuated vaccine strains with two O-serotype specificities. Biologicals 1994; 22:361-72. [PMID: 7540016 DOI: 10.1006/biol.1994.1055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
A considerable interest exists worldwide in the development of live attenuated oral vaccines against diarrhoeal diseases. In addition to vaccination against the corresponding pathogens, such vaccine strains can be used as carriers for the expression of protective antigens from other organisms. The antigenic repertoire of a given vaccine strain may thereby be extended, potentially leading to a bivalent vaccine. The lipopolysaccharide is known to be a major antigenic surface component of bacterial enteric pathogens. The feasibility of the development of combined vaccines based on live attenuated carriers expressing two O-serotype specificities is illustrated here by the development of candidate live oral vaccines against Shigella sonnei using Salmonella typhi and Vibrio cholerae as carriers. Various factors that may limit the potential of such hybrid strains as bivalent vaccines are discussed.
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Affiliation(s)
- J F Viret
- Swiss Serum and Vaccine Institute, Berne
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45
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Nishimura T, Favre D, Dürrenberger M, Michel MR, Ichihara I, Koblet H. Nuclear export of recombinant baculovirus nucleocapsids through small pore or nuclear-pore-like structure in Sf9 cells. Okajimas Folia Anat Jpn 1994; 71:83-97. [PMID: 7808726 DOI: 10.2535/ofaj1936.71.2-3_83] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Translocation of baculovirus nucleocapsids (45 nm in diameter, approximate length of 280-300 nm) from nucleoplasm to cytoplasm was studied morphologically using cryofixation and gold labeled wheat germ agglutinin (WGA-gold) during recombinant Autographa californica nuclear polyhedrosis virus infection in Sf9 cells. Nucleocapsids formed in the nucleoplasm migrated into protrusions of the nuclear envelope, but not into nuclear pore complexes. We found cross-like membranous structures. Small pores seemed to be in the protruding nuclear double membranes. The middle piece of a nucleocapsid was located within the small pore whereas the upper part was in the cytoplasm. Other nucleocapsids were situated within pores without colocalization of WGA-gold in the nuclear envelope. These results suggest that baculovirus nucleocapsids use small pores in the nuclear-derived membranes or incomplete nuclear pores in the nuclear envelope to migrate from the nucleoplasm to the cytoplasm, but not complete nuclear pore complexes proper.
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Affiliation(s)
- T Nishimura
- Department of Anatomy, Aichi Medical University, Japan
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46
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Michel MR, Favre D, Studer E, Arrigo AP, Kempf C. Modulation of thermoprotection and translational thermotolerance induced by Semliki Forest virus capsid protein. Eur J Biochem 1994; 223:791-7. [PMID: 8055955 DOI: 10.1111/j.1432-1033.1994.tb19054.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Low amounts of Semliki Forest virus capsid protein transferred into target cells by electroporation-mediated delivery (10(3)-10(4) molecules incorporated/cell) confer thermal resistance resulting in enhanced survival. Furthermore, when exposed to 43 degrees C, these cells display an enhanced expression of heat-shock protein-70 and a translational thermotolerance. Similarly, low amounts of capsid protein transferred into cells in which transcription is blocked by actinomycin D, also protect the translational machinery at 43 degrees C. In a cell-free translation system, added capsid protein appears to modulate translational efficiency of endogenous mRNAs. At approximately 1 molecule/ribosome, capsid protein is able to enhance translation at 30 degrees C and at 43 degrees C. In contrast, high concentrations of capsid protein are responsible for a marked inhibition of protein synthesis at 30 degrees C, but only hamper translational thermotolerance at 43 degrees C. Our results favor the hypothesis that small amounts of capsid protein trigger a chaperone-like activity that is able to protect the translational machinery from thermal damage.
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Affiliation(s)
- M R Michel
- Institute of Medical Microbiology, University of Berne, Switzerland
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47
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Abstract
Here we show that the capsid (C) protein of Semliki Forest virus (SFV) contains two nucleolar targeting signals (NOS) responsible for the karyophilic properties of this protein. When conjugated to the non-karyophilic carrier protein bovine serum albumin (BSA), the two synthetic nuclear localization sequences (NLS) of the C protein transferred with equal efficiency the carrier protein into the nucleolus of both higher and lower eukaryotic target cells.
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Affiliation(s)
- D Favre
- Institute of Medical Microbiology, University of Berne, Switzerland
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48
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Abstract
We have constructed a recombinant baculovirus which expressed the Semliki Forest (SFV) capsid (C) gene as a fusion protein under the control of the polyhedrin gene promoter. The sequence coding for C and part of the envelope E3 region were expressed as a polyprotein precursor. Spodoptera frugiperda (Sf9) insect cells infected with the recombinant virus produced a protein reacting with polyclonal rabbit antiserum that had been raised against the 33 kDa authentic C protein purified from SFV. Primer extension analyses showed that transcription from the polyhedrin promoter started in the late/very late consensus initiation motif. Due to its autoprotease activity, the recombinant C protein was contranslationally cleaved within its C-terminus and the mature protein remained undegraded for long periods of time. Spodoptera frugiperda cells infected with recombinant virus synthesized large amounts of C protein. The recombinant protein was karyophilic as is authentic SFV C protein and it was translocated into the nucleus; there, it was associated with nucleolus-like structures.
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Affiliation(s)
- D Favre
- Institute of Medical Microbiology, University of Berne, Switzerland
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49
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Favre D, Ngai PK, Timmis KN. Relatedness of a periplasmic, broad-specificity RNase from Aeromonas hydrophila to RNase I of Escherichia coli and to a family of eukaryotic RNases. J Bacteriol 1993; 175:3710-22. [PMID: 7685334 PMCID: PMC204786 DOI: 10.1128/jb.175.12.3710-3722.1993] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The isolation, sequencing, and characterization of a periplasmic RNase gene from Aeromonas hydrophila AH1133 is described. Following subcloning of the gene on a 2.7-kb PstI fragment, its direction of transcription and approximate location were determined. Analysis of the nucleotide sequence reveals that the gene is 645 bp long, coding for 215 amino acid residues with a total molecular weight of 24,215. A typical leader sequence is present at the beginning of the corresponding protein. Computer analysis revealed strong local similarities to Escherichia coli RNase I and to the active site of a family of eukaryotic RNases. Expression studies indicate that the RNase natural promoter functions poorly in E. coli. In this organism, the enzyme is mainly localized in the cytoplasm and periplasm, although high levels of expression lead to significant release into the extracellular medium. Functional and physical characterizations further indicate that the periplasmic and cytoplasmic enzymes of A. hydrophila are likely to be the counterparts of E. coli RNase I and its cytoplasmic form RNase I*: as for the E. coli enzymes, the A. hydrophila RNase forms have similar sizes and show broad specificity, and the periplasmic form is more active towards natural polymer RNA than its cytoplasmic counterpart. Both forms are relatively thermosensitive and are reversibly inactivated by up to 0.6% sodium dodecyl sulfate. Southern hybridization revealed homology to E. coli K-12 and Shigella sp. genomic DNA, a finding which correlates with the presence of secreted RNases in these organisms. In contrast, species of phylogenetically closer genera, such as Vibrio and Plesiomonas, did not hybridize to the A. hydrophila RNase gene.
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Affiliation(s)
- D Favre
- Département de Biochimie Médicale, Centre Médical Universitaire, Geneva, Switzerland
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50
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Viret JF, Cryz SJ, Lang AB, Favre D. Molecular cloning and characterization of the genetic determinants that express the complete Shigella serotype D (Shigella sonnei) lipopolysaccharide in heterologous live attenuated vaccine strains. Mol Microbiol 1993; 7:239-52. [PMID: 7680409 DOI: 10.1111/j.1365-2958.1993.tb01115.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The genetic determinants for the complete Shigella sonnei lipopolysaccharide (LPS) have been cloned, characterized by restriction mapping, and expressed in heterologous genetic backgrounds, including Salmonella typhi and Vibrio cholerae live attenuated vaccine strains. The rfb/rfc locus encoding the polymerized serotype-specific O polysaccharide was mapped within 23 kb of DNA isolated from S. sonnei virulence plasmid pWR105. A highly similar chromosomal DNA sequence was identified by Southern hybridization analysis in Plesiomonas shigelloides known to have the same O serotype specificity as S. sonnei. Expression studies of the rfb/rfc locus have shown that S. sonnei O polysaccharide is covalently bound to LPS cores of both the K-12 and R1 types, but neither to Salmonella (Ra-type) nor to V. cholerae O1 cores. In order to express a compatible core structure in the latter organisms, chromosomal rfa loci encoding R1-type LPS were isolated from both an Escherichia coli R1 strain (rfaR1) and from S. sonnei (rfasonnei). Restriction mapping and functional analysis of cloned DNA allowed us to localize the rfaR1 locus and to orient it with respect to the neighbouring cysE chromosomal marker. A high degree of sequence similarity was found at the DNA level between rfa loci of enterobacterial species characterized by R1-type LPS. Co-expression studies involving S. sonnei rfb/rfc and rfa loci propagated on compatible plasmids have shown that, at most, 13 to 14 kb of rfaR1 DNA are required for the expression of complete phase-I-like S. sonnei LPS in E. coli K-12 and S. typhi, whereas an adjacent region of about 3.5 kb is needed in the more stringent host, V. cholerae. S. sonnei O antigen expressed in a V. cholerae recombinant vaccine strain is present on the cell surface in a form suitable for the induction of a specific antibody response in vaccinated rabbits.
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Affiliation(s)
- J F Viret
- Swiss Serum and Vaccine Institute, Berne
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