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Iwanowitsch A, Diessner J, Bergmann B, Rudel T. The JMU-SalVac-System: A Novel, Versatile Approach to Oral Live Vaccine Development. Vaccines (Basel) 2024; 12:687. [PMID: 38932416 PMCID: PMC11209359 DOI: 10.3390/vaccines12060687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 06/13/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024] Open
Abstract
Salmonella enterica Serovar Typhi Ty21a (Ty21a) is the only licensed oral vaccine against typhoid fever. Due to its excellent safety profile, it has been used as a promising vector strain for the expression of heterologous antigens for mucosal immunization. As the efficacy of any bacterial live vector vaccine correlates with its ability to express and present sufficient antigen, the genes for antigen expression are traditionally located on plasmids with antibiotic resistance genes for stabilization. However, for use in humans, antibiotic selection of plasmids is not applicable, leading to segregational loss of the antigen-producing plasmid. Therefore, we developed an oral Ty21a-based vaccine platform technology, the JMU-SalVac-system (Julius-Maximilians-Universität Würzburg) in which the antigen delivery plasmids (pSalVac-plasmid-series) are stabilized by a ΔtyrS/tyrS+-based balanced-lethal system (BLS). The system is made up of the chromosomal knockout of the essential tyrosyl-tRNA-synthetase gene (tyrS) and the in trans complementation of tyrS on the pSalVac-plasmid. Further novel functional features of the pSalVac-plasmids are the presence of two different expression cassettes for the expression of protein antigens. In this study, we present the construction of vaccine strains with BLS plasmids for antigen expression. The expression of cytosolic and secreted mRFP and cholera toxin subunit B (CTB) proteins as model antigens is used to demonstrate the versatility of the approach. As proof of concept, we show the induction of previously described in vivo inducible promoters cloned into pSalVac-plasmids during infection of primary macrophages and demonstrate the expression of model vaccine antigens in these relevant human target cells. Therefore, antigen delivery strains developed with the JMU-SalVac technology are promising, safe and stable vaccine strains to be used against mucosal infections in humans.
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Affiliation(s)
| | - Joachim Diessner
- Department of Obstetrics and Gynecology, University Hospital Würzburg, 97080 Würzburg, Germany;
| | - Birgit Bergmann
- Chair of Microbiology, University of Würzburg, 97074 Würzburg, Germany;
| | - Thomas Rudel
- Chair of Microbiology, University of Würzburg, 97074 Würzburg, Germany;
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Wang Z, Zhao X, Wang Y, Sun C, Sun M, Gao X, Jia F, Shan C, Yang G, Wang J, Huang H, Shi C, Yang W, Qian A, Wang C, Jiang Y. In Vivo Production of HN Protein Increases the Protection Rates of a Minicircle DNA Vaccine against Genotype VII Newcastle Disease Virus. Vaccines (Basel) 2021; 9:vaccines9070723. [PMID: 34358140 PMCID: PMC8310180 DOI: 10.3390/vaccines9070723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 06/26/2021] [Accepted: 06/26/2021] [Indexed: 01/09/2023] Open
Abstract
The Cre-recombinase mediated in vivo minicircle DNA vaccine platform (CRIM) provided a novel option to replace a traditional DNA vaccine. To further improve the immune response of our CRIM vaccine, we designed a dual promoter expression plasmid named pYL87 which could synthesize short HN protein under a prokaryotic in vivo promoter PpagC and full length HN protein of genotype VII Newcastle disease virus (NDV) under the previous eukaryotic CMV promoter at the same time. Making use of the self-lysed Salmonella strain as a delivery vesicle, chickens immunized with the pYL87 construction showed an increased serum haemagglutination inhibition antibody response, as well as an increased cell proliferation level and cellular IL-4 and IL-18 cytokines, compared with the previous CRIM vector pYL47. After the virus challenge, the pYL87 vector could provide 80% protection compared to 50% protection against genotype VII NDV in pYL47 immunized chickens, indicating a promising dual promoter strategy used in vaccine design.
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Li X, Bleumink-Pluym NMC, Luijkx YMCA, Wubbolts RW, van Putten JPM, Strijbis K. MUC1 is a receptor for the Salmonella SiiE adhesin that enables apical invasion into enterocytes. PLoS Pathog 2019; 15:e1007566. [PMID: 30716138 PMCID: PMC6375660 DOI: 10.1371/journal.ppat.1007566] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 02/14/2019] [Accepted: 01/06/2019] [Indexed: 01/08/2023] Open
Abstract
The cellular invasion machinery of the enteric pathogen Salmonella consists of a type III secretion system (T3SS) with injectable virulence factors that induce uptake by macropinocytosis. Salmonella invasion at the apical surface of intestinal epithelial cells is inefficient, presumably because of a glycosylated barrier formed by transmembrane mucins that prevents T3SS contact with host cells. We observed that Salmonella is capable of apical invasion of intestinal epithelial cells that express the transmembrane mucin MUC1. Knockout of MUC1 in HT29-MTX cells or removal of MUC1 sialic acids by neuraminidase treatment reduced Salmonella apical invasion but did not affect lateral invasion that is not hampered by a defensive barrier. A Salmonella deletion strain lacking the SiiE giant adhesin was unable to invade intestinal epithelial cells through MUC1. SiiE-positive Salmonella closely associated with the MUC1 layer at the apical surface, but invaded Salmonella were negative for the adhesin. Our findings uncover that the transmembrane mucin MUC1 is required for Salmonella SiiE-mediated entry of enterocytes via the apical route. The bacterial pathogen Salmonella enterica is one of the most common causes of human foodborne infection affecting millions of people worldwide each year. To establish infection, Salmonella needs to cross the mucus layer and invade intestinal epithelial cells from the apical surface. However, the apical surface of intestinal epithelial cells is covered with a defensive barrier of large glycosylated transmembrane mucins. These large proteins prevent contact between the Salmonella type III secretion needle and the host plasma membrane thereby preventing invasion. We show for the first time that MUC1, one of the intestinal apical transmembrane mucins, facilitates Salmonella invasion. The Salmonella giant adhesin SiiE is the adhesin responsible for engaging MUC1 and the interaction is mediated by glycans on MUC1. We propose that SiiE interacts with MUC1 in a zipper-like manner that involves repetitive domains in both proteins. Adhesin-receptor interactions are essential for bacterial infection of host cells and key factors in determining target tissues and host range of bacteria. The SiiE-MUC1 invasion pathway may explain tropism of different Salmonella strains and provide a novel target for infection intervention and prevention.
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Affiliation(s)
- Xinyue Li
- Department of Infectious Diseases & Immunology, Utrecht University, Utrecht, The Netherlands
| | | | - Yvette M. C. A. Luijkx
- Department of Infectious Diseases & Immunology, Utrecht University, Utrecht, The Netherlands
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Richard W. Wubbolts
- Department of Biochemistry and Cell Biology, Utrecht University, Utrecht, The Netherlands
| | - Jos P. M. van Putten
- Department of Infectious Diseases & Immunology, Utrecht University, Utrecht, The Netherlands
| | - Karin Strijbis
- Department of Infectious Diseases & Immunology, Utrecht University, Utrecht, The Netherlands
- * E-mail:
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Jayachandran R, Gumienny A, Bolinger B, Ruehl S, Lang MJ, Fucile G, Mazumder S, Tchang V, Woischnig AK, Stiess M, Kunz G, Claudi B, Schmaler M, Siegmund K, Li J, Dertschnig S, Holländer G, Medina E, Karrer U, Moshous D, Bumann D, Khanna N, Rossi SW, Pieters J. Disruption of Coronin 1 Signaling in T Cells Promotes Allograft Tolerance while Maintaining Anti-Pathogen Immunity. Immunity 2019; 50:152-165.e8. [PMID: 30611611 DOI: 10.1016/j.immuni.2018.12.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 10/18/2018] [Accepted: 12/10/2018] [Indexed: 11/18/2022]
Abstract
The ability of the immune system to discriminate self from non-self is essential for eradicating microbial pathogens but is also responsible for allograft rejection. Whether it is possible to selectively suppress alloresponses while maintaining anti-pathogen immunity remains unknown. We found that mice deficient in coronin 1, a regulator of naive T cell homeostasis, fully retained allografts while maintaining T cell-specific responses against microbial pathogens. Mechanistically, coronin 1-deficiency increased cyclic adenosine monophosphate (cAMP) concentrations to suppress allo-specific T cell responses. Costimulation induced on microbe-infected antigen presenting cells was able to overcome cAMP-mediated immunosuppression to maintain anti-pathogen immunity. In vivo pharmacological modulation of this pathway or a prior transfer of coronin 1-deficient T cells actively suppressed allograft rejection. These results define a coronin 1-dependent regulatory axis in T cells important for allograft rejection and suggest that modulation of this pathway may be a promising approach to achieve long-term acceptance of mismatched allografts.
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Affiliation(s)
| | | | | | | | | | - Geoffrey Fucile
- Swiss Institute of Bioinformatics, sciCORE Computing Center, University of Basel, Basel, Switzerland
| | | | | | - Anne-Kathrin Woischnig
- Department of Biomedicine, University and University Hospital of Basel, Basel, Switzerland
| | | | | | | | - Mathias Schmaler
- Department of Biomedicine, University and University Hospital of Basel, Basel, Switzerland
| | | | | | - Simone Dertschnig
- Department of Biomedicine, University and University Hospital of Basel, Basel, Switzerland
| | - George Holländer
- Department of Biomedicine, University and University Hospital of Basel, Basel, Switzerland; Department of Paediatrics, University of Oxford, Oxford, UK
| | - Eva Medina
- Helmholtz Center for Infection Research, Braunschweig, Germany
| | - Urs Karrer
- Division of Infectious Diseases and Department of Medicine, Cantonal Hospital of Winterthur, Winterthur, Switzerland
| | - Despina Moshous
- Université Paris Descartes-Sorbonne Paris Cité, Institut Imagine, Paris, France and APHP Hôpital Universitaire Necker-Enfants Malades, Unité d'Immunologie-Hématologie et Rhumatologie Pédiatrique, Paris, France
| | - Dirk Bumann
- Biozentrum, University of Basel, Basel, Switzerland
| | - Nina Khanna
- Department of Biomedicine, University and University Hospital of Basel, Basel, Switzerland; Division of Infectious Diseases, University and University Hospital of Basel, Switzerland
| | - Simona W Rossi
- Department of Biomedicine, University and University Hospital of Basel, Basel, Switzerland
| | - Jean Pieters
- Biozentrum, University of Basel, Basel, Switzerland.
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Galen JE, Curtiss R. The delicate balance in genetically engineering live vaccines. Vaccine 2014; 32:4376-4385. [PMID: 24370705 PMCID: PMC4069233 DOI: 10.1016/j.vaccine.2013.12.026] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 11/26/2013] [Accepted: 12/10/2013] [Indexed: 11/24/2022]
Abstract
Contemporary vaccine development relies less on empirical methods of vaccine construction, and now employs a powerful array of precise engineering strategies to construct immunogenic live vaccines. In this review, we will survey various engineering techniques used to create attenuated vaccines, with an emphasis on recent advances and insights. We will further explore the adaptation of attenuated strains to create multivalent vaccine platforms for immunization against multiple unrelated pathogens. These carrier vaccines are engineered to deliver sufficient levels of protective antigens to appropriate lymphoid inductive sites to elicit both carrier-specific and foreign antigen-specific immunity. Although many of these technologies were originally developed for use in Salmonella vaccines, application of the essential logic of these approaches will be extended to development of other enteric vaccines where possible. A central theme driving our discussion will stress that the ultimate success of an engineered vaccine rests on achieving the proper balance between attenuation and immunogenicity. Achieving this balance will avoid over-activation of inflammatory responses, which results in unacceptable reactogenicity, but will retain sufficient metabolic fitness to enable the live vaccine to reach deep tissue inductive sites and trigger protective immunity. The breadth of examples presented herein will clearly demonstrate that genetic engineering offers the potential for rapidly propelling vaccine development forward into novel applications and therapies which will significantly expand the role of vaccines in public health.
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Affiliation(s)
- James E Galen
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Division of Geographic Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Roy Curtiss
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute and School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
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Zhang J, De Masi L, John B, Chen W, Schifferli DM. Improved delivery of the OVA-CD4 peptide to T helper cells by polymeric surface display on Salmonella. Microb Cell Fact 2014; 13:80. [PMID: 24898796 PMCID: PMC4055283 DOI: 10.1186/1475-2859-13-80] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 05/19/2014] [Indexed: 12/31/2022] Open
Abstract
Background Autotransporter proteins represent a treasure trove for molecular engineers who modify Gram-negative bacteria for the export or secretion of foreign proteins across two membrane barriers. A particularly promising direction is the development of autotransporters as antigen display or secretion systems. Immunologists have been using ovalbumin as a reporter antigen for years and have developed sophisticated tools to detect specific T cells that respond to ovalbumin. Although ovalbumin-expressing bacteria are being used to trace T cell responses to colonizing or invading pathogens, current constructs for ovalbumin presentation have not been optimized. Results The activation of T helper cells in response to ovalbumin was improved by displaying the OVA-CD4 reporter epitope as a multimer on the surface of Salmonella and fused to the autotransporter MisL. Expression was optimized by including tandem in vivo promoters and two post-segregational killing systems for plasmid stabilization. Conclusions The use of an autotransporter protein to present relevant epitope repeats on the surface of bacteria, combined with additional techniques favoring stable and efficient in vivo transcription, optimizes antigen presentation to T cells. The technique of multimeric epitope surface display should also benefit the development of new Salmonella or other enterobacterial vaccines.
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Affiliation(s)
| | | | | | | | - Dieter M Schifferli
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania 19104, USA.
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Chin'ombe N, Ruhanya V. Recombinant Salmonella Bacteria Vectoring HIV/AIDS Vaccines. Open Virol J 2013; 7:121-6. [PMID: 24478808 PMCID: PMC3905348 DOI: 10.2174/1874357901307010121] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 11/13/2013] [Accepted: 11/18/2013] [Indexed: 11/29/2022] Open
Abstract
HIV/AIDS is an important public health problem globally. An affordable, easy-to-deliver and protective HIV
vaccine is therefore required to curb the pandemic from spreading further. Recombinant Salmonella bacteria can be
harnessed to vector HIV antigens or DNA vaccines to the immune system for induction of specific protective immunity.
These are capable of activating the innate, humoral and cellular immune responses at both mucosal and systemic
compartments. Several studies have already demonstrated the utility of live recombinant Salmonella in delivering
expressed foreign antigens as well as DNA vaccines to the host immune system. This review gives an overview of the
studies in which recombinant Salmonella bacteria were used to vector HIV/AIDS antigens and DNA vaccines. Most of
the recombinant Salmonella-based HIV/AIDS vaccines developed so far have only been tested in animals (mainly mice)
and are yet to reach human trials.
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Affiliation(s)
- Nyasha Chin'ombe
- Department of Medical Microbiology, University of Zimbabwe, Harare, Zimbabwe ; Division of Medical Virology, University of Cape Town, Cape Town, South Africa
| | - Vurayai Ruhanya
- Department of Medical Microbiology, University of Zimbabwe, Harare, Zimbabwe
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Barat S, Willer Y, Rizos K, Claudi B, Mazé A, Schemmer AK, Kirchhoff D, Schmidt A, Burton N, Bumann D. Immunity to intracellular Salmonella depends on surface-associated antigens. PLoS Pathog 2012; 8:e1002966. [PMID: 23093937 PMCID: PMC3475680 DOI: 10.1371/journal.ppat.1002966] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 08/14/2012] [Indexed: 01/05/2023] Open
Abstract
Invasive Salmonella infection is an important health problem that is worsening because of rising antimicrobial resistance and changing Salmonella serovar spectrum. Novel vaccines with broad serovar coverage are needed, but suitable protective antigens remain largely unknown. Here, we tested 37 broadly conserved Salmonella antigens in a mouse typhoid fever model, and identified antigen candidates that conferred partial protection against lethal disease. Antigen properties such as high in vivo abundance or immunodominance in convalescent individuals were not required for protectivity, but all promising antigen candidates were associated with the Salmonella surface. Surprisingly, this was not due to superior immunogenicity of surface antigens compared to internal antigens as had been suggested by previous studies and novel findings for CD4 T cell responses to model antigens. Confocal microscopy of infected tissues revealed that many live Salmonella resided alone in infected host macrophages with no damaged Salmonella releasing internal antigens in their vicinity. In the absence of accessible internal antigens, detection of these infected cells might require CD4 T cell recognition of Salmonella surface-associated antigens that could be processed and presented even from intact Salmonella. In conclusion, our findings might pave the way for development of an efficacious Salmonella vaccine with broad serovar coverage, and suggest a similar crucial role of surface antigens for immunity to both extracellular and intracellular pathogens. Salmonella infections cause extensive morbidity and mortality worldwide. A vaccine that prevents systemic Salmonella infections is urgently needed but suitable antigens remain largely unknown. In this study we identified several antigen candidates that mediated protective immunity to Salmonella in a mouse typhoid fever model. Interestingly, all these antigens were associated with the Salmonella surface. This suggested that similar antigen properties might be relevant for CD4 T cell dependent immunity to intracellular pathogens like Salmonella, as for antibody-dependent immunity to extracellular pathogens. Detailed analysis revealed that Salmonella surface antigens were not generally more immunogenic compared to internal antigens. However, internal antigens were inaccessible for CD4 T cell recognition of a substantial number of infected host cells that contained exclusively live intact Salmonella. Together, these results might pave the way for development of an efficacious Salmonella vaccine, and provide a basis to facilitate antigen identification for Salmonella and possibly other intracellular pathogens.
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Affiliation(s)
- Somedutta Barat
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Yvonne Willer
- Junior Group “Mucosal Infections”, Hannover Medical School, Hannover, Germany
| | - Konstantin Rizos
- Department of Molecular Biology, Max-Planck-Institute for Infection Biology, Berlin, Germany
| | - Beatrice Claudi
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Alain Mazé
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Anne K. Schemmer
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Dennis Kirchhoff
- Immunomodulation Group, Deutsches Rheuma-Forschungszentrum Berlin, Berlin, Germany
| | - Alexander Schmidt
- Proteomics Core Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - Neil Burton
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Dirk Bumann
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
- Junior Group “Mucosal Infections”, Hannover Medical School, Hannover, Germany
- Department of Molecular Biology, Max-Planck-Institute for Infection Biology, Berlin, Germany
- * E-mail:
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IFNγ expression by an attenuated strain of Salmonella enterica serovar Typhimurium improves vaccine efficacy in susceptible TLR4-defective C3H/HeJ mice. Med Microbiol Immunol 2012; 202:49-61. [PMID: 22684724 DOI: 10.1007/s00430-012-0248-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 05/25/2012] [Indexed: 10/27/2022]
Abstract
C3H/HeJ mice carry a mutated allele of TLR4 gene (TLR4 ( d )) and thus are hyporesponsive to the lethal effects of lipopolysaccharide (LPS). Characteristically, however, the mice are also hypersusceptible to infections, particularly by Gram-negative bacteria such as Salmonella enterica serovar Typhimurium (S. typhimurium) and are known to be difficult to vaccinate against virulent exposure. This is observed despite the expression of wild-type allele of Nramp1 gene, another important determinant of Salmonella susceptibility. In contrast, C3H/HeN mice (TLR4 ( n ) Nramp1 ( n )) express a functional TLR4 protein and are resistant to infection, even by virulent strains of S. typhimurium. In the present study, we describe the immune system-enhancing properties of an attenuated strain of S. typhimurium engineered to express murine IFN-γ. This strain (designated GIDIFN) was able to modulate immune responses following systemic inoculation by upregulating the production of inflammatory mediators (IL-6 and IL-12) and anti-bacterial effector molecules (nitric oxide; NO). Consequently, this led to a more effective control of bacterial proliferation in systemic target organs in both C3H/HeJ and C3H/HeN mice. Although evidence for the enhancement in immune responses could be observed as early as few hours post-inoculation, sustained improvements required 2-3 days to manifest. Vaccination of C3H/HeJ mice with GIDIFN strain, even at low doses, conferred a significantly higher degree of protection against challenge with virulent Salmonella in susceptible C3H/HeJ mice. Our data demonstrate that IFNγ-expressing Salmonella are immunogenic and confer excellent protection against virulent challenge in susceptible C3H/HeJ mice; in addition they may be used as an effective mucosal delivery vectors against virulent infection and for boosting immune responses in immunodeficient hosts.
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Employing Live Microbes for Vaccine Delivery. DEVELOPMENT OF NOVEL VACCINES 2012. [PMCID: PMC7123214 DOI: 10.1007/978-3-7091-0709-6_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/29/2022]
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Live attenuated Salmonella vaccines displaying regulated delayed lysis and delayed antigen synthesis to confer protection against Mycobacterium tuberculosis. Infect Immun 2011; 80:815-31. [PMID: 22144485 DOI: 10.1128/iai.05526-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Live recombinant attenuated Salmonella vaccine (RASV) strains have great potential to induce protective immunity against Mycobacterium tuberculosis by delivering M. tuberculosis antigens. Recently, we reported that, in orally immunized mice, RASV strains delivering the M. tuberculosis early secreted antigenic target 6-kDa (ESAT-6) protein and culture filtrate protein 10 (CFP-10) antigens via the Salmonella type III secretion system (SopE amino-terminal region residues 1 to 80 with two copies of ESAT-6 and one copy of CFP-10 [SopE(Nt80)-E2C]) afforded protection against aerosol challenge with M. tuberculosis. Here, we constructed and evaluated an improved Salmonella vaccine against M. tuberculosis. We constructed translational fusions for the synthesis of two copies of ESAT-6 plus CFP-10 fused to the OmpC signal sequence (OmpC(SS)-E2C) and amino acids 44 to 338 of antigen 85A (Ag85A(294)) flanked by the signal sequence (SS) and C-terminal peptide (CT) of β-lactamase (Bla(SS)-Ag85A(294)-Bla(CT)) to enable delivery via the Salmonella type II secretion system. The genes expressing these proteins were cloned as an operon transcribed from P(trc) into isogenic Asd(+)/MurA(+) pYA3681 lysis vector derivatives with different replication origins (pBR, p15A, pSC101), resulting in pYA4890, pYA4891, and pYA4892 for SopE(Nt80)-E2C/Ag85A(294) synthesis and pYA4893 and pYA4894 for OmpC(SS)-E2C/Ag85A(294) synthesis. Mice orally immunized with the RASV χ11021 strain engineered to display regulated delayed lysis and regulated delayed antigen synthesis in vivo and harboring pYA4891, pYA4893, or pYA4894 elicited significantly greater humoral and cellular immune responses, and the RASV χ11021 strain afforded a greater degree of protection against M. tuberculosis aerosol challenge in mice than RASVs harboring any other Asd(+)/MurA(+) lysis plasmid and immunization with M. bovis BCG, demonstrating that RASV strains displaying regulated delayed lysis with delayed antigen synthesis resulted in highly immunogenic delivery vectors for oral vaccination against M. tuberculosis infection.
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Kong Q, Six DA, Roland KL, Liu Q, Gu L, Reynolds CM, Wang X, Raetz CRH, Curtiss R. Salmonella synthesizing 1-dephosphorylated [corrected] lipopolysaccharide exhibits low endotoxic activity while retaining its immunogenicity. THE JOURNAL OF IMMUNOLOGY 2011; 187:412-23. [PMID: 21632711 DOI: 10.4049/jimmunol.1100339] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The development of safe live, attenuated Salmonella vaccines may be facilitated by detoxification of its LPS. Recent characterization of the lipid A 1-phosphatase, LpxE, from Francisella tularensis allowed us to construct recombinant, plasmid-free strains of Salmonella that produce predominantly 1-dephosphorylated lipid A, similar to the adjuvant approved for human use. Complete lipid A 1-dephosphorylation was also confirmed under low pH, low Mg(2+) culture conditions, which induce lipid A modifications. LpxE expression in Salmonella reduced its virulence in mice by five orders of magnitude. Moreover, mice inoculated with these detoxified strains were protected against wild-type challenge. Candidate Salmonella vaccine strains synthesizing pneumococcal surface protein A (PspA) were also confirmed to possess nearly complete lipid A 1-dephosphorylation. After inoculation by the LpxE/PspA strains, mice produced robust levels of anti-PspA Abs and showed significantly improved survival against challenge with wild-type Streptococcus pneumoniae WU2 compared with vector-only-immunized mice, validating Salmonella synthesizing 1-dephosphorylated lipid A as an Ag-delivery system.
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Affiliation(s)
- Qingke Kong
- Center for Infectious Diseases and Vaccinology, Biodesign Institute and School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
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Comparison of a regulated delayed antigen synthesis system with in vivo-inducible promoters for antigen delivery by live attenuated Salmonella vaccines. Infect Immun 2010; 79:937-49. [PMID: 21134969 DOI: 10.1128/iai.00445-10] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Induction of strong immune responses against a vectored antigen in hosts immunized with live attenuated Salmonella vaccines is related in part to the amount of antigen delivered and the overall fitness of the Salmonella vector in relation to its ability to stimulate the host immune system. Constitutive high-level antigen synthesis causes a metabolic burden to the vaccine vector strain that can reduce the vaccine strain's ability to interact with host lymphoid tissues, resulting in a compromised immune response. A solution to this problem is the use of systems that regulate antigen gene expression, permitting high levels of antigen synthesis only after the vaccine strain has reached its target tissues. In vivo-inducible promoters (IVIPs) are often used to accomplish this. We recently developed an alternative strategy, a regulated delayed antigen synthesis (RDAS) system, in which the LacI-repressible P(trc) promoter controls antigen gene expression by adding arabinose. In this paper, we compared the RDAS system with two commonly used IVIPs, P(ssaG) and P(pagC). Three nearly identical plasmids, differing only in the promoter used to direct transcription of the pneumococcal pspA gene, P(trc), P(ssaG), or P(pagC), were constructed and introduced into isogenic Salmonella vaccine strains with or without arabinose-inducible LacI synthesis. Mice immunized with the RDAS strain developed slightly higher titers of mucosal and serum anti-PspA antibodies than P(pagC)-immunized mice, while titers in mice immunized with the P(ssaG) strain were 100-fold lower. Both the RDAS and P(pagC) strains conferred similar levels of protection against Streptococcus pneumoniae challenge, significantly greater than those for the P(ssaG) strain or controls. Thus, RDAS provides another choice for inclusion in the live vaccine design to increase immunogenicity.
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Carleton HA. Pathogenic bacteria as vaccine vectors: teaching old bugs new tricks. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2010; 83:217-22. [PMID: 21165341 PMCID: PMC3002147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
As our scientific knowledge of bacteria grows, so does our ability to manipulate these bacteria to protect rather than infect mammalian hosts from a diverse group of diseases. The old axiom that the best way to protect from a disease is to get infected in the first place is not feasible in the face of the diverse group of pathogens that infect humans. Therefore, reprogramming bacteria to protect against diverse bacterial, viral, and parasitic diseases as well as cancer is a new reality in the field of vaccines.
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Salmonella vaccine vectors displaying delayed antigen synthesis in vivo to enhance immunogenicity. Infect Immun 2010; 78:3969-80. [PMID: 20605977 DOI: 10.1128/iai.00444-10] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We have developed a regulated delayed antigen synthesis (RDAS) system for use in recombinant attenuated Salmonella vaccine (RASV) strains to enhance immune responses by reducing the adverse effects of high-level antigen synthesis. This system includes a chromosomal repressor gene, lacI, expressed from the arabinose-regulated araC PBAD promoter. LacI serves to regulate expression from a plasmid promoter, Ptrc, that directs antigen synthesis. In the presence of arabinose LacI is produced, which binds to Ptrc, blocking antigen synthesis. In vivo, an arabinose-poor environment, the concentration of LacI decreases with each cell division, allowing increased antigen synthesis. To optimize the system and for comparison, we altered the lacI ribosome-binding site, start codon, and/or codon content to construct RDAS strains chi9095, chi9959, and chi9241, synthesizing from low to high levels of LacI, respectively, and non-RDAS strain chi9555 as a control. We evaluated this system with two test antigens, the green fluorescent protein for initial in vitro assessment and the Streptococcus pneumoniae PspA protein for validation of our system in mice. All RASV strains expressing PspA generated high antilipopolysaccharide antibody titers, indicating that expression of lacI did not interfere with the capacity to induce an immune response. Strain chi9241 induced significantly higher anti-PspA IgG and IgA antibody titers than strain chi9555, which expressed PspA constitutively. Anti-PspA antibody titers were inversely correlated to the level of LacI synthesis. Strain chi9241 also induced significantly greater protective efficacy against challenge with virulent S. pneumoniae. These results suggest that regulated delayed antigen synthesis is useful for improving immunogenicity of RASV strains.
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Bumann D, Behre C, Behre K, Herz S, Gewecke B, Gessner JE, von Specht BU, Baumann U. Systemic, nasal and oral live vaccines against Pseudomonas aeruginosa: A clinical trial of immunogenicity in lower airways of human volunteers. Vaccine 2010; 28:707-13. [DOI: 10.1016/j.vaccine.2009.10.080] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2008] [Revised: 09/30/2009] [Accepted: 10/14/2009] [Indexed: 10/20/2022]
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Schroeder J, Aebischer T. Recombinant outer membrane vesicles to augment antigen-specific live vaccine responses. Vaccine 2009; 27:6748-54. [DOI: 10.1016/j.vaccine.2009.08.106] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 08/13/2009] [Accepted: 08/22/2009] [Indexed: 11/17/2022]
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18
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Zhang X, Pan Z, Fang Q, Zheng J, Hu M, Jiao X. An auto-inducible Escherichia coli lysis system controlled by magnesium. J Microbiol Methods 2009; 79:199-204. [DOI: 10.1016/j.mimet.2009.09.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Revised: 07/26/2009] [Accepted: 09/01/2009] [Indexed: 10/20/2022]
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Morin CE, Kaper JB. Use of stabilized luciferase-expressing plasmids to examine in vivo-induced promoters in the Vibrio cholerae vaccine strain CVD 103-HgR. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 2009; 57:69-79. [PMID: 19678844 PMCID: PMC2906245 DOI: 10.1111/j.1574-695x.2009.00580.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Live, attenuated Vibrio cholerae vaccines can induce potent immune responses after only a single oral dose. The strategy of harnessing these strains to present antigens from heterologous pathogens to the mucosal immune system shows great promise. To fully realize this possibility, V. cholerae strains must be created that stably express antigens in vivo in sufficient quantity to generate an immune response. In vivo-induced promoters have been shown to increase the stability and immunogenicity of foreign antigens expressed from multicopy plasmids. We report the construction of a series of genetically stabilized plasmids expressing luciferase as a heterologous protein from the following in vivo-induced promoters: V. cholerae P(argC), P(fhuC) and P(vca1008), and Salmonella enterica serovar Typhi P(ompC). We demonstrate that several of these expression plasmids meet two critical criteria for V. cholerae live vector vaccine studies. First, the plasmids are highly stable in the V. cholerae vaccine strain CVD 103-HgR at low copy number, in the absence of selective pressure. Second, real-time bioluminescent imaging (BLI) demonstrates inducible in vivo expression of the promoters in the suckling mouse model of V. cholerae colonization. Moreover, the use of BLI allows for direct quantitative comparison of in vivo expression from four different promoters at various time points.
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Affiliation(s)
- Cara E Morin
- Department of Microbiology & Immunology, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Abstract
Attenuated Salmonella Typhi vaccine strains hold great promise as live vectors for presentation of foreign antigens from unrelated bacterial, viral and parasitic pathogens to the immune system. Although this approach has proved quite successful in experimental animal models for eliciting antigen-specific mucosal, humoral and cellular responses, results have been disappointing for clinical trials carried out thus far. We hypothesize that the paucity of human responses to foreign antigens delivered by live vectors suggests that the strains and genetic approaches used to date have resulted in overattenuated vaccine strains with severely reduced immunogenicity. However, remarkable advances have now been made in the genetics of foreign antigen expression, understanding mechanisms of live vector immunity and refining immunization strategies. The time has now come for development of multivalent live vectors in which stable antigen expression and export is balanced with metabolic fitness to create highly immunogenic vaccines.
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Van Gerven N, Sleutel M, Deboeck F, De Greve H, Hernalsteens JP. Surface display of the receptor-binding domain of the F17a-G fimbrial adhesin through the autotransporter AIDA-I leads to permeability of bacterial cells. MICROBIOLOGY-SGM 2009; 155:468-476. [PMID: 19202095 DOI: 10.1099/mic.0.022327-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Surface exposure of antigens on bacterial cells can be critical for eliciting an effective antibody response. Therefore, we investigated the cellular localization of the fimbrial F17a-G receptor-binding domain, fused to the translocator domain of the AIDA-I autotransporter. Synthesis of the fusion protein, under the control of the L-arabinose-inducible PBAD promoter, was shown to permeabilize Escherichia coli K-12 and Salmonella enterica serovar Typhimurium cells. The presence of permeable cells interfered with several methods that are typically used to determine surface exposure of proteins, such as protease treatment and whole-cell ELISA. Double immunofluorescence microscopy, using a second antibody directed against beta-galactosidase, a bacterial protein expressed in the cytoplasm, allowed the simultaneous detection of antigen expression and permeability in individual cells.
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Affiliation(s)
- Nani Van Gerven
- Onderzoeksgroep Genetische Virologie, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Mike Sleutel
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Francine Deboeck
- Onderzoeksgroep Genetische Virologie, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Henri De Greve
- Structural Biology Brussels, Department of Molecular and Cellular Interactions, VIB, B-1050 Brussels, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Jean-Pierre Hernalsteens
- Onderzoeksgroep Genetische Virologie, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
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22
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Pathangey L, Kohler JJ, Isoda R, Brown TA. Effect of expression level on immune responses to recombinant oral Salmonella enterica serovar Typhimurium vaccines. Vaccine 2009; 27:2707-11. [PMID: 19428883 DOI: 10.1016/j.vaccine.2009.02.072] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 01/30/2009] [Accepted: 02/05/2009] [Indexed: 10/21/2022]
Abstract
Live, attenuated Salmonella has been used to express heterologous antigens for development of oral vaccines. Often, expression must be regulated because of deleterious effects on the Salmonella vector. The effect of varying expression levels on immune response parameters has not been well defined. In this study we introduced mutations in the -10 region of the trc promoter in the expression plasmid to generate series of vaccine strains with different levels of expression of a model antigen, the hemagglutinin HagB from Porphyromonas gingivalis. There was no difference in growth rates of the Salmonella vaccine strains containing the wild-type, the mutant plasmids or the empty expression vector. The primary IgG response in serum in mice orally immunized with the wild-type strain peaked 3-4 weeks earlier than the intermediate expression level strains, suggesting that high expression levels may favor an earlier response. While there was a trend for anti-HagB recall responses to correlate with higher expression level, the peak levels were not significantly different even for expression levels as low as 33% of wild-type. A similar trend in terms of response level was seen with serum and salivary IgA. The subclass of the IgG response was predominately IgG2a regardless of expression level, consistent with a Th1 response. These data suggest that isotype distribution, immune response level and T helper cell profile are largely unaffected over a wide range of expression levels.
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Affiliation(s)
- Latha Pathangey
- Department of Oral Biology, University of Florida, Gainesville, FL 32610, United States
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Abstract
Over the last decade, significant advances have been made in the methodology for studying immune responses in vivo. It is now possible to follow almost every aspect of pathogen-specific immunity using in vivo models that incorporate physiological infectious doses and natural routes of infection. This new ability to study immunity in a relevant physiological context will greatly expand our understanding of the dynamic interplay between host and pathogen. Visualizing the resolution of primary infection and the development of long-term immunological memory should also aid the development of new vaccines and therapeutics for infectious diseases. In this review, we will describe the application of in vivo visualization technology to Salmonella infection, describe our current understanding of Salmonella-specific immunity, and discuss some unanswered questions that remain in this model.
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Affiliation(s)
- James J. Moon
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, MN, 55455
- Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, 55455
| | - Stephen J. McSorley
- Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, 55455
- Center for Immunology, University of Minnesota Medical School, Minneapolis, MN, 55455
- Center for Infectious Diseases & Microbiology Translational Research, University of Minnesota Medical School, Minneapolis, MN, 55455
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Influence of promoter, gene copy number, and preexisting immunity on humoral and cellular responses to a vectored antigen delivered by a Salmonella enterica vaccine. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2008; 16:78-87. [PMID: 19005022 DOI: 10.1128/cvi.00253-08] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Attenuated Salmonella strains are currently in production as vaccines for protection of animals against salmonellosis. Such commercial strains offer the potential to deliver heterologous antigen to protect animals against other diseases. One vaccine strain, attenuated Salmonella enterica serovar Typhimurium (STM-1), was tested for the ability to deliver ovalbumin and to induce immune responses in mice. Two vaccine trials were performed testing the influence of promoter choice, the location of the encoding DNA (plasmid or chromosome), and the effect of preexisting homologous or heterologous immunity. The results demonstrated that humoral and T-cell responses were induced from either of two promoters, from either the plasmid or the chromosome, and that preexposure to the empty homologous vector, STM-1, or the heterologous vector, S. enterica serovar Enteritidis, had no detrimental effect on subsequent antigen-specific responses. In the case of homologous preexposure, responses were generally greater, and this was correlated with an increased uptake of Salmonella by macrophages in vitro after opsonization with immune sera.
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25
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Expression ofin vivo-inducibleSalmonella entericapromoters during infection ofCaenorhabditis elegans. FEMS Microbiol Lett 2008; 278:236-41. [DOI: 10.1111/j.1574-6968.2007.01001.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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26
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Cancer immunotherapy based on recombinant Salmonella enterica serovar Typhimurium aroA strains secreting prostate-specific antigen and cholera toxin subunit B. Cancer Gene Ther 2007; 15:85-93. [PMID: 18084243 DOI: 10.1038/sj.cgt.7701109] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Prostate cancer is the most common malignant tumor in men and is normally associated with increased serum levels of prostate-specific antigen (PSA). Therefore, PSA is one potential target for a prostate cancer vaccine. In this study we analyzed the functionality of new bacterial PSA vaccines, expressed and secreted via the hemolysin (HlyA) secretion system of Escherichia coli, the prototype of Type I secretion systems (T1SS) using an attenuated Salmonella enterica serovar Typhimurium aroA strain as carrier. The data demonstrate that a bacterial live vaccine encompassing T1SS in combination with cholera toxin subunit B can be successfully used for delivery of PSA to induce cytotoxic CD8+ T-cell responses resulting in an efficient prevention of tumor growth in mice.
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27
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In vivo gene regulation in Salmonella spp. by a salicylate-dependent control circuit. Nat Methods 2007; 4:937-42. [DOI: 10.1038/nmeth1107] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Accepted: 09/18/2007] [Indexed: 01/04/2023]
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Abstract
Salmonella enterica is an important pathogen of animals and humans causing a variety of infectious diseases. The large number of cases of typhoid fever due to S. enterica serovar Typhi infections gives rise to the continuous need for improved vaccines against this life-threatening infection. However, S. enterica is also an interesting organism to act as a live attenuated carrier for the presentation of recombinant heterologous antigens. Comprehensive experimental studies have been performed and a detailed knowledge of the molecular mechanisms of important virulence factors is available. This allows the rationale design of improved Salmonella carrier strains and the development of novel strategies for the expression and presentation of recombinant antigens. Here, we review recent advances in generation of live attenuated Salmonella vaccines and discuss criteria for expression strategies of heterologous antigens by Salmonella carrier strains.
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29
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Loessner H, Endmann A, Leschner S, Bauer H, Zelmer A, zur Lage S, Westphal K, Weiss S. Improving live attenuated bacterial carriers for vaccination and therapy. Int J Med Microbiol 2007; 298:21-6. [PMID: 17702649 DOI: 10.1016/j.ijmm.2007.07.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Live attenuated bacteria are well established as vaccines. Thus, their use as carriers for prophylactic and therapeutic macromolecules is a logical consequence. Here we describe several experimental applications of bacteria to carry heterologous macromolecules into the murine host. First, Listeria monocytogenes are described that are able to transfer eukaryotic expression plasmids into host cells for gene therapy. High multiplicities of infection are still required for efficient gene transfer and we point out some of the bottlenecks that counteract a more efficient transfer and application in vivo. Then, we describe Salmonella enterica serovar Typhimurium (S. typhimurium) as an expression plasmid transfer vehicle for oral DNA vaccination of mice. We demonstrate that the stabilization of the plasmid transformants results in an improved immune response. Stabilization was achieved by replacing the origin of replication of the original high-copy-number plasmid by a low-copy-number origin. Finally, we describe Salmonella carriers for the improved expression of heterologous proteins. We introduce a system in which the plasmid is carried as a single copy during cultivation but is amplified several fold upon infection of the host. Using the same in vivo inducible promoter for both protein expression and plasmid amplification, a substantial increase in antigen expression in vivo can be achieved. A modification of this approach is the introduction of inducible gene expression in vivo with a low-molecular-weight compound. Using P(BAD) promoter and L-arabinose as inducer we were able to deliberately activate genes in the bacterial carrier. No background activity could be observed with P(BAD) such that an inducible suicide gene could be introduced. This is adding an important safety feature to such live attenuated carrier bacteria.
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Affiliation(s)
- Holger Loessner
- Molecular Immunology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, D-38124 Braunschweig, Germany
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30
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Spreng S, Dietrich G, Weidinger G. Rational design of Salmonella-based vaccination strategies. Methods 2006; 38:133-43. [PMID: 16414270 DOI: 10.1016/j.ymeth.2005.09.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2005] [Accepted: 09/16/2005] [Indexed: 11/30/2022] Open
Abstract
A permanently growing body of information is becoming available about the quality of protective immune responses induced by mucosal immunization. Attenuated live bacterial vaccines can be administered orally and induce long-lasting protective immunity in humans without causing major side effects. An attenuated Salmonella enterica serovar Typhi strain is registered as live oral vaccine against typhoid fever and has been in use for more than two decades. Recombinant attenuated Salmonella strains are also an attractive means of delivering heterologous antigens to the immune system, thereby, stimulating strong mucosal and systemic immune responses and consequently provide an efficient platform technology to design novel vaccination strategies. This includes the choice of heterologous protective antigens and their expression under the control of appropriate promoters within the carrier strain. The availability of well-characterized attenuated mutants of Salmonella concomitantly supports fine tuning of immune response triggered against heterologous antigens. Exploring different mucosal sites as a potential route of immunization has to be taken into account as an additional important way to modulate immune responses according to clinical requirements. This article focuses on the rational design of strategies to modulate appropriate immunological effector functions on the basis of selection of (i) attenuating mutations of the Salmonella strains, (ii) specific expression systems for the heterologous antigens, and (iii) route of mucosal administration.
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Affiliation(s)
- Simone Spreng
- Berna Biotech Ltd., Bacterial Vaccine Research, Rehhagstr. 79, CH-3018 Berne, Switzerland.
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31
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Wiedig CA, Kramer U, Garbom S, Wolf-Watz H, Autenrieth IB. Induction of CD8+ T cell responses by Yersinia vaccine carrier strains. Vaccine 2005; 23:4984-98. [PMID: 15985316 DOI: 10.1016/j.vaccine.2005.05.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Revised: 04/21/2005] [Accepted: 05/27/2005] [Indexed: 10/25/2022]
Abstract
Yersinia enterocolitica employs a type III secretion system (TTSS) to target virulence factors (e.g. YopE) into the cytosol of the host cells. We utilized the TTSS to introduce a recombinant antigen directly into the cytosol of host cells and to investigate the potential of Y. enterocolitica and Y. pseudotuberculosis as live carrier for vaccines. The model antigen ovalbumin (Ova) was fused to defined secretion or translocation domains of the Yersinia effector protein YopE and introduced into attenuated mutant strains of Y. enterocolitica and Y. pseudotuberculosis. In vitro experiments showed secretion and translocation of YopE-Ova hybrid proteins into host cells. To investigate the resulting immune responses, mice expressing transgenic Ova-specific T cell receptors were used. Both Y. enterocolitica and Y. pseudotuberculosis mutants induced efficaciously Ova-specific CD8+ T cell responses. The translocation domain of YopE was required for induction of CD8+ T cell responses in vivo, but not for T cell responses induced in vitro. The in vivo frequency of Ova-specific splenic T cells was up to six-fold higher in mice immunized with YopE-Ova-translocating Y. enterocolitica/Y. pseudotuberculosis mutants than in control mice. The Ova-specific T cells were shown to produce high amounts of IFN-gamma. We did not observe significant Ova-specific CD4+ T cell or antibody responses upon vaccination with either of the strains. In conclusion, Yersinia live carrier vaccine strains are suitable to target antigens into the MHC class I pathway and stimulate CD8+ T cell responses and thus, might be useful in vaccine approaches against intracellular pathogens.
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Affiliation(s)
- Carolin A Wiedig
- Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen, Elfriede-Aulhorn-Street 6, D-72076 Tübingen, Germany
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Husseiny MI, Hensel M. Evaluation of an intracellular-activated promoter for the generation of live Salmonella recombinant vaccines. Vaccine 2005; 23:2580-90. [PMID: 15780440 DOI: 10.1016/j.vaccine.2004.11.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2004] [Revised: 10/21/2004] [Accepted: 11/09/2004] [Indexed: 11/30/2022]
Abstract
Salmonella enterica serovar Typhimurium is a versatile host organism for the generation of recombinant live vaccines for mucosal immunization. We investigated the performance of an intracellular-activated promoter for expression of heterologous antigens by Salmonella carrier strains. We observed that intracellular expressed antigens were more efficient in elicitation of humoral and cellular immune responses than constitutively expressed antigens. Furthermore, the intracellular-activated promoter was more efficient in combination with a carrier strain deficient in SPI2 gene sseC than with the conventional aroA strain. We propose that intracellular-activated promoters will be useful tools for construction of efficient recombinant live vaccines.
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Affiliation(s)
- Mohamed I Husseiny
- Institut für Klinische Mikrobiologie, Immunologie und Hygiene, FAU Erlangen-Nürnberg, Wasserturmstrasse 3-5, D-91054 Erlangen, Germany
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Westendorf AM, Gunzer F, Deppenmeier S, Tapadar D, Hunger JK, Schmidt MA, Buer J, Bruder D. Intestinal immunity of Escherichia coli NISSLE 1917: a safe carrier for therapeutic molecules. ACTA ACUST UNITED AC 2005; 43:373-84. [PMID: 15708311 DOI: 10.1016/j.femsim.2004.10.023] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2003] [Revised: 05/25/2004] [Accepted: 10/06/2004] [Indexed: 12/20/2022]
Abstract
The development of novel approaches that allow accurate targeting of therapeutics to the intestinal mucosa is a major task in the research on intestinal inflammation. For the first time, a live genetically modified bacterial strain has been approved by Dutch authorities as a therapeutic agent for experimental therapy of intestinal bowel disease (IBD) in humans. Genetically modified probiotics can very well be used as carriers for localized antigen delivery into the intestine. Therapeutic safety, however, of such a carrier organism, is crucial, especially when a specific probiotic strain has to be used under diseased conditions. In this study, we tested the potential of Escherichia coli NISSLE 1917 to serve as a safe carrier for targeted delivery of recombinant proteins to the intestinal mucosa. In a well-defined and very sensitive immunological system, we demonstrate that intestinal recombinant E. coli NISSLE 1917 has no effect on migration, clonal expansion and activation status of specific CD4+ T cells, neither in healthy mice nor in animals with acute colitis. Furthermore, recombinant E. coli NISSLE 1917 has no effect on the induction or breakdown of peripheral T-cell tolerance in an autoimmune environment. The excellent colonization properties of E. coli NISSLE 1917 render this strain an ideal candidate as carrier organism for gut-focused in situ synthesis of therapeutic molecules.
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Affiliation(s)
- Astrid M Westendorf
- Arbeitsgruppe Mukosale Immunität, Gesellschaft für Biotechnologische Forschung, Mascheroder Weg 1, D-38124 Braunschweig, Germany
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34
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Husseiny MI, Hensel M. Rapid method for the construction of Salmonella enterica Serovar Typhimurium vaccine carrier strains. Infect Immun 2005; 73:1598-605. [PMID: 15731059 PMCID: PMC1064926 DOI: 10.1128/iai.73.3.1598-1605.2005] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serovar Typhimurium is a versatile organism for the generation of live recombinant vaccines for mucosal immunization. Various strategies have been devised for the stable and efficient expression of heterologous antigens by attenuated S. enterica strains, but these methods often require complex manipulations. Use of phage lambda Red recombinase has recently been devised for gene replacements in Escherichia coli and S. enterica after introduction of PCR products. Based on this method, we have developed an approach that allows the integration of recombinant expression cassettes for heterologous antigens in a single step. The recombinant construct is integrated into the chromosome and is devoid of any selective marker such as antibiotic resistance. We observed the stable expression of model antigens without selective pressure. In addition, the method allows the simultaneous generation of attenuating mutations by gene deletions. The novel "knock-in" approach allows the rapid and efficient construction of recombinant Salmonella strains as vaccine carriers.
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Affiliation(s)
- Mohamed I Husseiny
- Institut für Klinische Mikrobiologie, Immunologie und Hygiene, FAU Erlangen-Nürnberg, Wasserturmstr. 3-5, D-91054 Erlangen, Germany
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35
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Arnold H, Bumann D, Felies M, Gewecke B, Sörensen M, Gessner JE, Freihorst J, von Specht BU, Baumann U. Enhanced immunogenicity in the murine airway mucosa with an attenuated Salmonella live vaccine expressing OprF-OprI from Pseudomonas aeruginosa. Infect Immun 2004; 72:6546-53. [PMID: 15501786 PMCID: PMC523058 DOI: 10.1128/iai.72.11.6546-6553.2004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We constructed an oral live vaccine based on the attenuated aroA mutant Salmonella enterica serovar Typhimurium strain SL3261 expressing outer membrane proteins F and I (OprF-OprI) from Pseudomonas aeruginosa and investigated it in a mouse model. Strains with in vivo inducible protein expression with the PpacC promoter showed good infection rates and immunogenicity but failed to engender detectable antibodies in the lung. However, a systemic booster vaccination following an oral primary immunization yielded high immunoglobulin A (IgA) and IgG antibody levels in both upper and lower airways superior to conventional systemic or mucosal booster vaccination alone. In addition, the proportion of IgG1 and IgG2a antibodies suggested that the systemic booster does not alter the more TH1-like type of response induced by the oral Salmonella primary vaccination. We conclude that an oral primary systemic booster vaccination strategy with an appropriate mucosal vector may be advantageous in diseases with the risk of P. aeruginosa airway infection, such as cystic fibrosis.
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Affiliation(s)
- Heinz Arnold
- Department of Pediatric Pulmonology and Neonatology, Hannover Medical School, 30623, Germany
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36
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Affiliation(s)
- Camille N Kotton
- Infectious Diseases Division, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
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Rollenhagen C, Sörensen M, Rizos K, Hurvitz R, Bumann D. Antigen selection based on expression levels during infection facilitates vaccine development for an intracellular pathogen. Proc Natl Acad Sci U S A 2004; 101:8739-44. [PMID: 15173591 PMCID: PMC423265 DOI: 10.1073/pnas.0401283101] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Indexed: 01/09/2023] Open
Abstract
Vaccines effective against intracellular pathogens could save the lives of millions of people every year, but vaccine development has been hampered by the slow largely empirical search for protective antigens. In vivo highly expressed antigens might represent a small attractive antigen subset that could be rapidly evaluated, but experimental evidence supporting this rationale, as well as practical strategies for its application, is largely lacking because of technical difficulties. Here, we used Salmonella strains expressing differential amounts of a fluorescent model antigen during infection to show that, in a mouse typhoid fever model, CD4 T cells preferentially recognize abundant Salmonella antigens. To identify a large number of natural Salmonella antigens with high expression levels during infection, we used a quantitative in vivo screening strategy. Immunization studies with five particularly attractive candidates revealed two highly protective antigens that might permit the development of an improved typhoid fever vaccine. In conclusion, we have established a rationale and an experimental strategy that will substantially facilitate vaccine development for Salmonella and possibly other intracellular pathogens.
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Affiliation(s)
- Claudia Rollenhagen
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Schumannstrasse 21/22, D-10117 Berlin, Germany
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Rang C, Galen JE, Kaper JB, Chao L. Fitness cost of the green fluorescent protein in gastrointestinal bacteria. Can J Microbiol 2004; 49:531-7. [PMID: 14608419 DOI: 10.1139/w03-072] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There are surprisingly few studies that have successfully used the green fluorescent protein (GFP) as a quantitative reporter in selection experiments screening for inducible bacterial promoters. One explanation is that GFP expression may confer a fitness cost for bacteria. To test this possibility, we monitored the doubling time in enteric bacteria expressing GFP. Four bacterial species, Escherichia coli, enterohaemorrhagic E. coli, Shigella flexneri, Salmonella typhi, and Vibrio cholerae, were examined. The level of GFP expression was varied by using a salt-inducible promoter. After accounting for the increase in doubling time resulting from elevated osmolarity, the doubling time of all bacteria was found to increase proportionally with GFP expression, and some strains were more affected than others. Cultures of the bacteria most affected by GFP exhibited a proportion of elongated cells, which suggests that GFP production could interfere with cell division in these strains. The results in this study show that GFP is costly to bacteria and suggest that overly active promoters should be difficult to obtain from a genomic promoter library. They also suggest that the chances of succeeding in using GFP as a reporter in selection experiments are increased by growing the bacteria for the fewest number of generations and by subduing the expression of GFP whenever possible, such as by using a low copy vector to clone the library.
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Affiliation(s)
- Camilla Rang
- Division of Biology, University of California, San Diego, La Jolla, CA 92093-0116, USA.
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Rizos K, Lattemann CT, Bumann D, Meyer TF, Aebischer T. Autodisplay: efficacious surface exposure of antigenic UreA fragments from Helicobacter pylori in Salmonella vaccine strains. Infect Immun 2003; 71:6320-8. [PMID: 14573651 PMCID: PMC219551 DOI: 10.1128/iai.71.11.6320-6328.2003] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Live attenuated Salmonella strains expressing antigens of pathogens are promising oral vaccine candidates. There is growing evidence that the topology of expression of the foreign antigens can have a dramatic impact on the immunogenicity. We examined the potential of the AIDA-I (Escherichia coli adhesin involved in diffuse adherence) autotransporter domain to display antigenic fragments of the urease A subunit of Helicobacter pylori for the induction of a protective immune response. In the murine H. pylori model, protection is mainly mediated by CD4(+) T cells, and we therefore used the AIDA-I expression system to successfully express both nearly full-length UreA and defined T-helper-cell epitopes on the surface of an attenuated Salmonella enterica serovar Typhimurium vaccine strain. Surface exposure of the large UreA fragment or of one UreA T-cell epitope mediated a significant reduction in the level of H. pylori in immunized mice after challenge infection, whereas conventional cytoplasmic expression of UreA in Salmonella had no effect. These results support the concept that surface display increases the immunogenicity of recombinant antigens expressed on oral live vaccine carriers and further demonstrate the feasibility of immunizing against H. pylori with Salmonella vaccine strains expressing CD4(+) T-cell epitopes.
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Affiliation(s)
- Konstantin Rizos
- Creatogen AG, D-86156 Augsburg. Max-Planck-Institut für Infektionsbiologie, Abteilung Molekulare Biologie, D-10117 Berlin, Germany
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Sörensen M, Lippuner C, Kaiser T, Misslitz A, Aebischer T, Bumann D. Rapidly maturing red fluorescent protein variants with strongly enhanced brightness in bacteria. FEBS Lett 2003; 552:110-4. [PMID: 14527670 DOI: 10.1016/s0014-5793(03)00856-1] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A rapidly maturing variant of the red fluorescent protein DsRed was optimized for bacterial expression by random mutagenesis. The brightest variant contains six mutations, two of which (S4T and a silent mutation in codon 2) explain most of the fluorescence enhancement. The novel variants are expressed at 9-60-fold higher levels in Escherichia coli compared to DsRed.T3, but are not superior fluorophores on a per molecule basis. In contrast to previously available DsRed variants, DsRed.T3_S4T is sufficiently bright to monitor Salmonella gene expression in infected animals using flow cytometry. However, no fluorescence enhancement was observed in Leishmania or HeLa cells, indicating that these novel variants are specifically useful for bacteria.
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Affiliation(s)
- Meike Sörensen
- Department of Molecular Biology, Max-Planck-Institute for Infection Biology, Schumannstr. 21/22, D-10117 Berlin, Germany
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Bumann D. T cell receptor-transgenic mouse models for studying cellular immune responses to Salmonella in vivo. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 2003; 37:105-9. [PMID: 12832113 DOI: 10.1016/s0928-8244(03)00064-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Cellular immune responses are crucial both for protective immunity against salmonellosis, and for the immunogenicity of oral vaccines based on avirulent live Salmonella as antigen carriers. The crucial early steps of T cell induction are difficult to investigate in conventional animals, but recently developed T cell receptor (TCR)-transgenic models allow visualization of antigen-specific T cells in vivo while they become induced. In this review, the results obtained with four different TCR-transgenic Salmonella infection models are described, and advantages and potential limits of each of the different models are compared.
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Affiliation(s)
- Dirk Bumann
- Max-Planck-Institut für Infektionsbiologie, Abteilung Molekulare Biologie, Schumannstrasse 21/22, 10117 Berlin, Germany.
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Wendland M, Bumann D. Optimization of GFP levels for analyzing Salmonella gene expression during an infection. FEBS Lett 2002; 521:105-8. [PMID: 12067736 DOI: 10.1016/s0014-5793(02)02834-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Green fluorescent protein (GFP) is an attractive reporter for Salmonella gene expression analysis but might interfere with virulence when expressed at high levels. To identify suitable GFP levels, we constructed a series of Salmonella strains expressing different amounts of GFP and measured their fluorescence and colonization levels in infected mice. The results show that GFP concentrations in the range of 7000-200,000 molecules per Salmonella cell are detectable in ex vivo samples using flow cytometry, and cause no major Salmonella virulence defect. Appropriate GFP levels can be obtained with weak promoters and stable GFP, or strong promoters and destabilized GFP.
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Affiliation(s)
- Meike Wendland
- Max-Planck-Institute for Infection Biology, Department of Molecular Biology, Schumannstr. 21/22, D-10117 Berlin, Germany
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