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Flaiz M, Baur T, Gaibler J, Kröly C, Dürre P. Establishment of Green- and Red-Fluorescent Reporter Proteins Based on the Fluorescence-Activating and Absorption-Shifting Tag for Use in Acetogenic and Solventogenic Anaerobes. ACS Synth Biol 2022; 11:953-967. [PMID: 35081709 DOI: 10.1021/acssynbio.1c00554] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Anaerobic bacteria are promising biocatalysts to produce industrially relevant products from nonfood feedstocks. Several anaerobes are genetically accessible, and various molecular tools for metabolic engineering are available. Still, the use of bright fluorescent reporters, which are commonly used in molecular biological approaches is limited under anaerobic conditions. Therefore, the establishment of different anaerobic fluorescent reporter proteins is of great interest. Here, we present the establishment of the green- and red-fluorescent reporter proteins greenFAST and redFAST for use in different solventogenic and acetogenic bacteria. Green fluorescence of greenFAST was bright in Clostridium saccharoperbutylacetonicum, Clostridium acetobutylicum, Acetobacterium woodii, and Eubacterium limosum, while only C. saccharoperbutylacetonicum showed bright red fluorescence when producing redFAST. We used both reporter proteins in C. saccharoperbutylacetonicum for multicolor approaches. These include the investigation of the co-culture dynamics of metabolically engineered strains. Moreover, we established a tightly regulated inducible two-plasmid system and used greenFAST and redFAST to track the coexistence and interaction of both plasmids under anaerobic conditions in C. saccharoperbutylacetonicum. The establishment of greenFAST and redFAST as fluorescent reporters opens the door for further multicolor approaches to investigate cell dynamics, gene expression, or protein localization under anaerobic conditions.
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Affiliation(s)
- Maximilian Flaiz
- Institute of Microbiology and Biotechnology, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Tina Baur
- Institute of Microbiology and Biotechnology, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Jana Gaibler
- Institute of Microbiology and Biotechnology, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Christian Kröly
- Institute of Microbiology and Biotechnology, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Peter Dürre
- Institute of Microbiology and Biotechnology, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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A Bivalent Recombinant Mycobacterium bovis BCG Expressing the S1 Subunit of the Pertussis Toxin Induces a Polyfunctional CD4 + T Cell Immune Response. BIOMED RESEARCH INTERNATIONAL 2019; 2019:9630793. [PMID: 30941374 PMCID: PMC6420988 DOI: 10.1155/2019/9630793] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 12/30/2018] [Indexed: 12/15/2022]
Abstract
Background A recombinant BCG strain expressing the genetically detoxified S1 subunit of pertussis toxin 9K/129G (rBCG-S1PT), previously constructed by our research group, demonstrated the ability to develop high protection in mouse models of pertussis challenge which correlated with the induction of a Th1 immune response pattern. The Th1 immune response induced by rBCG-S1PT treatment was also confirmed in the murine orthotopic bladder cancer model, in which the intravesical instillation of rBCG-S1PT resulted in an improved antitumor effect. Based on these observations, we hypothesize that the reengineering of the S1PT expression in BCG could increase the efficiency of the protective Th1 immune response in order to develop a new alternative of immunotherapy in bladder cancer treatment. Objectives To construct rBCG strains expressing S1PT from extrachromosomal (rBCG-S1PT) and integrative vectors (rBCG-Sli), or their combination, generating the bivalent strain (rBCG-S1+S1i), and to evaluate the respective immunogenicity of rBCG strains in mice. Methods Mycobacterial plasmids were constructed by cloning the s1pt gene under integrative and extrachromosomal vectors and used to transform BCG, individually or in combination. Antigen expression and localization were confirmed by Western blot. Mice were immunized with wild-type BCG or the rBCG strains, and cytokines quantification and flow cytometry analysis were performed in splenocytes culture stimulated with mycobacterial-specific proteins. Findings S1PT expression was confirmed in all rBCG strains. The extrachromosomal vector directs S1PT to the cell wall-associated fraction, while the integrative vector directs its expression mainly to the intracellular fraction. Higher levels of IFN-γ were observed in the splenocytes culture from the group immunized with rBCG-S1i in comparison to BCG or rBCG-S1PT. rBCG-S1+S1i showed higher levels of CD4+ IFN-γ+ and double-positive CD4+ IFN-γ+ TNF-α+ T cells. Conclusions rBCG-S1+S1i was able to express the two forms of S1PT and elicited higher induction of polyfunctional CD4+ T cells, indicating enhanced immunogenicity and suggesting its use as immunotherapy for bladder cancer.
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Metabolic engineering of Corynebacterium glutamicum for fermentative production of chemicals in biorefinery. Appl Microbiol Biotechnol 2018; 102:3915-3937. [DOI: 10.1007/s00253-018-8896-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 02/23/2018] [Accepted: 02/26/2018] [Indexed: 01/22/2023]
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Rizzi C, Peiter AC, Oliveira TL, Seixas ACP, Leal KS, Hartwig DD, Seixas FK, Borsuk S, Dellagostin OA. Stable expression of Mycobacterium bovis antigen 85B in auxotrophic M. bovis bacillus Calmette-Guérin. Mem Inst Oswaldo Cruz 2017; 112:123-130. [PMID: 28177046 PMCID: PMC5293121 DOI: 10.1590/0074-02760160360] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 10/31/2016] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Bovine tuberculosis (TB) is a zoonotic disease caused by Mycobacterium
bovis, responsible for causing major losses in livestock. A cost
effective alternative to control the disease could be herd vaccination. The
bacillus Calmette-Guérin (BCG) vaccine has a limited efficacy against bovine TB,
but can improved by over-expression of protective antigens. The M.
bovis antigen 85B demonstrates ability to induce protective immune
response against bovine TB in animal models. However, current systems for the
construction of recombinant BCG expressing multiple copies of the gene result in
strains of low genetic stability that rapidly lose the plasmid in vivo. Employing
antibiotic resistance as selective markers, these systems also compromise vaccine
safety. We previously reported the construction of a stable BCG expression system
using auxotrophic complementation as a selectable marker. OBJECTIVES The fundamental aim of this study was to construct strains of M.
bovis BCG Pasteur and the auxotrophic M. bovis BCG
ΔleuD expressing Ag85B and determine their stability in
vivo. METHODS Employing the auxotrophic system, we constructed rBCG strains that expressed
M. bovis Ag85B and compared their stability with a
conventional BCG strain in mice. Stability was measured in terms of bacterial
growth on the selective medium and retention of antigen expression. FINDINGS The auxotrophic complementation system was highly stable after 18 weeks, even
during in vivo growth, as the selective pressure and expression of antigen were
maintained comparing to the conventional vector. MAIN CONCLUSION The Ag85B continuous expression within the host may generate a stronger and
long-lasting immune response compared to conventional systems.
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Affiliation(s)
- Caroline Rizzi
- Universidade Federal de Pelotas, Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Programa de Pós-Graduação em Biotecnologia, Pelotas, RS, Brasil
| | - Ana Carolina Peiter
- Universidade Federal de Pelotas, Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Programa de Pós-Graduação em Biotecnologia, Pelotas, RS, Brasil
| | - Thaís Larré Oliveira
- Universidade Federal de Pelotas, Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Programa de Pós-Graduação em Biotecnologia, Pelotas, RS, Brasil
| | - Amilton Clair Pinto Seixas
- Universidade Federal de Pelotas, Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Programa de Pós-Graduação em Biotecnologia, Pelotas, RS, Brasil
| | - Karen Silva Leal
- Universidade Federal de Pelotas, Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Programa de Pós-Graduação em Biotecnologia, Pelotas, RS, Brasil
| | - Daiane Drawanz Hartwig
- Universidade Federal de Pelotas, Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Programa de Pós-Graduação em Biotecnologia, Pelotas, RS, Brasil.,Universidade Federal de Pelotas, Instituto de Biologia, Departamento de Microbiologia e Parasitologia, RS, Brasil
| | - Fabiana Kommling Seixas
- Universidade Federal de Pelotas, Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Programa de Pós-Graduação em Biotecnologia, Pelotas, RS, Brasil
| | - Sibele Borsuk
- Universidade Federal de Pelotas, Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Programa de Pós-Graduação em Biotecnologia, Pelotas, RS, Brasil
| | - Odir Antônio Dellagostin
- Universidade Federal de Pelotas, Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Programa de Pós-Graduação em Biotecnologia, Pelotas, RS, Brasil
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Kang MK, Lee J, Um Y, Lee TS, Bott M, Park SJ, Woo HM. Synthetic biology platform of CoryneBrick vectors for gene expression in Corynebacterium glutamicum and its application to xylose utilization. Appl Microbiol Biotechnol 2014; 98:5991-6002. [PMID: 24706215 DOI: 10.1007/s00253-014-5714-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 03/04/2014] [Accepted: 03/17/2014] [Indexed: 10/25/2022]
Abstract
Currently, the majority of tools in synthetic biology have been designed and constructed for model organisms such as Escherichia coli and Saccharomyces cerevisiae. In order to broaden the spectrum of organisms accessible to such tools, we established a synthetic biological platform, called CoryneBrick, for gene expression in Corynebacterium glutamicum as a set of E. coli-C. glutamicum shuttle vectors whose elements are interchangeable with BglBrick standard parts. C. glutamicum is an established industrial microorganism for the production of amino acids, proteins, and commercially promising chemicals. Using the CoryneBrick vectors, we showed various time-dependent expression profiles of a red fluorescent protein. This CoryneBrick platform was also applicable for two-plasmid expression systems with a conventional C. glutamicum expression vector. In order to demonstrate the practical application of the CoryneBrick vectors, we successfully reconstructed the xylose utilization pathway in the xylose-negative C. glutamicum wild type by fast BglBrick cloning methods using multiple genes encoding for xylose isomerase and xylulose kinase, resulting in a growth rate of 0.11 ± 0.004 h(-1) and a xylose uptake rate of 3.35 mmol/gDW/h when 1 % xylose was used as sole carbon source. Thus, CoryneBrick vectors were shown to be useful engineering tools in order to exploit Corynebacterium as a synthetic platform for the production of chemicals by controllable expression of the genes of interest.
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Affiliation(s)
- Min-Kyoung Kang
- Clean Energy Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 136-791, Republic of Korea
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Ly MA, Liew EF, Le NB, Coleman NV. Construction and evaluation of pMycoFos, a fosmid shuttle vector for Mycobacterium spp. with inducible gene expression and copy number control. J Microbiol Methods 2011; 86:320-6. [DOI: 10.1016/j.mimet.2011.06.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 06/01/2011] [Accepted: 06/05/2011] [Indexed: 11/29/2022]
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A stable plasmid system for heterologous antigen expression in attenuated Vibrio anguillarum. Vaccine 2011; 29:6986-93. [PMID: 21791231 DOI: 10.1016/j.vaccine.2011.07.036] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 06/16/2011] [Accepted: 07/11/2011] [Indexed: 11/21/2022]
Abstract
To stably synthesize heterologous protein in an attenuated Vibrio anguillarum strain (MVAV6203) for potential multivalent live vaccine application, plasmids with different replicons were used to construct protein expression systems in this work. The gfp fragment under control of a strict low-iron-regulated promoter P(viua) was inserted into seven plasmids with varied replicons derived from pAT153, pACYC184, pBBR1, pEC, pMW118, pRK2, and pSC101, to generate seven corresponding plasmids. Our results revealed that the plasmid pUTat with the replicon from pAT153 was retained by 100% of the host cells and mediated stable expression of heterologous protein in antibiotic-free medium within 250 generations. Further analyses in animal model (zebrafish larvae) demonstrated that the constructed plasmid pUTat was well retained by bacteria and continuously expressed GFP in vivo in zebrafish. The gapA40 gene, encoding Glyceraldehyde-3-phosphate dehydrogenase from the fish pathogen Edwardsiella tarda, was introduced into the pUTat-based protein expression system, and transformed into V. anguillarum MVAV6203. The resultant recombinant vector vaccine 6203/pUTatgap was evaluated in turbot (Scophtalmus maximus). After 30 days post vaccination, the fish showed an increased survival ratio by 80% and 67% under the challenge of wild V. anguillarum and E. tarda, respectively. Our results suggested that the pUTat-based antigen expression system had great potential with its efficiency and stability in the design of bacterial vector vaccine.
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Bashiri G, Rehan AM, Greenwood DR, Dickson JMJ, Baker EN. Metabolic engineering of cofactor F420 production in Mycobacterium smegmatis. PLoS One 2010; 5:e15803. [PMID: 21209917 PMCID: PMC3012119 DOI: 10.1371/journal.pone.0015803] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 11/24/2010] [Indexed: 01/16/2023] Open
Abstract
Cofactor F420 is a unique electron carrier in a number of microorganisms including Archaea and Mycobacteria. It has been shown that F420 has a direct and important role in archaeal energy metabolism whereas the role of F420 in mycobacterial metabolism has only begun to be uncovered in the last few years. It has been suggested that cofactor F420 has a role in the pathogenesis of M. tuberculosis, the causative agent of tuberculosis. In the absence of a commercial source for F420, M. smegmatis has previously been used to provide this cofactor for studies of the F420-dependent proteins from mycobacterial species. Three proteins have been shown to be involved in the F420 biosynthesis in Mycobacteria and three other proteins have been demonstrated to be involved in F420 metabolism. Here we report the over-expression of all of these proteins in M. smegmatis and testing of their importance for F420 production. The results indicate that co–expression of the F420 biosynthetic proteins can give rise to a much higher F420 production level. This was achieved by designing and preparing a new T7 promoter–based co-expression shuttle vector. A combination of co–expression of the F420 biosynthetic proteins and fine-tuning of the culture media has enabled us to achieve F420 production levels of up to 10 times higher compared with the wild type M. smegmatis strain. The high levels of the F420 produced in this study provide a suitable source of this cofactor for studies of F420-dependent proteins from other microorganisms and for possible biotechnological applications.
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Affiliation(s)
- Ghader Bashiri
- Structural Biology Laboratory, School of Biological Sciences, The University of Auckland, Auckland, New Zealand.
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Chang Y, Mead D, Dhodda V, Brumm P, Fox BG. One-plasmid tunable coexpression for mycobacterial protein-protein interaction studies. Protein Sci 2009; 18:2316-25. [PMID: 19760663 PMCID: PMC2788286 DOI: 10.1002/pro.242] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 08/28/2009] [Accepted: 09/01/2009] [Indexed: 11/06/2022]
Abstract
A single plasmid that allows controlled coexpression has been developed for use in mycobacteria. The tetracycline inducible promoter, PtetO, was used to provide tetracycline-dependent induction of one gene, while the Psmyc, Pimyc, or Phsp promoters were used to provide three different levels of constitutive expression of a second gene. The functions of these four individual promoters were established using green fluorescent protein (GFP) and a newly identified red fluorescence inducible protein from Geobacillus sterothermophilus strain G1.13 (RFIP) as reporters. The tandem use of GFP and RFIP as reporter genes allowed optimization of the tunable coexpression in Mycobacterium smegmatis; either time at a fixed inducer concentration or changes in inducer concentration could be used to control the protein:protein ratio. This single vector system was used to coexpress the two-protein Mycobacterium tuberculosis stearoyl-CoA Delta(9) desaturase complex (integral membrane desaturase Rv3229c and NADPH oxidoreductase Rv3230c) in M. smegmatis. The catalytic activity was found to increase in a manner corresponding to increasing the level of Rv3230c relative to a fixed level of Rv3229c. This system, which can yield finely tuned coexpression of the fatty acid desaturase complex in mycobacteria, may be useful for study of other multicomponent complexes. Furthermore, the tunable coexpression strategy used herein should also be applicable in other species with minor modifications.
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Affiliation(s)
- Yong Chang
- Biophysics Graduate Degree Program, University of Wisconsin-Madison433 Babcock Drive, Madison, Wisconsin 53706-1549
- Department of Biochemistry, University of Wisconsin-Madison433 Babcock Drive, Madison, Wisconsin 53706-1549
| | - David Mead
- Lucigen Corporation2120 W. Greenview Drive, Middleton, Wisconsin 53562
| | - Vinay Dhodda
- Lucigen Corporation2120 W. Greenview Drive, Middleton, Wisconsin 53562
| | - Phil Brumm
- Lucigen Corporation2120 W. Greenview Drive, Middleton, Wisconsin 53562
| | - Brian G Fox
- Biophysics Graduate Degree Program, University of Wisconsin-Madison433 Babcock Drive, Madison, Wisconsin 53706-1549
- Department of Biochemistry, University of Wisconsin-Madison433 Babcock Drive, Madison, Wisconsin 53706-1549
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Abstract
The importance of plasmids for molecular research cannot be underestimated. These double-stranded DNA units that replicate independently of the chromosomal DNA are as valuable to bacterial geneticists as a carpenter's hammer. Fortunately, today the mycobacterial research community has a number of these genetic tools at its disposal, and the development of these tools has greatly accelerated the study of mycobacterial pathogens. However, working with mycobacterial cloning plasmids is still not always as straightforward as working with Escherichia coli plasmids, and therefore a number of precautions and potential pitfalls will be discussed in this chapter.
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Affiliation(s)
- Farahnaz Movahedzadeh
- Institute for Tuberculosis Research, College of Pharmacy, Rm 412, University of Illinois at Chicago, 833 S Wood St, Chicago, Illinois 60612-7231, USA.
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Lü L, Cao HD, Zeng HQ, Wang PL, Wang LJ, Liu SN, Xiang TX. Recombinant Mycobacterium smegmatis mc(2)155 vaccine expressing outer membrane protein 26 kDa antigen affords therapeutic protection against Helicobacter pylori infection. Vaccine 2008; 27:972-8. [PMID: 19111590 DOI: 10.1016/j.vaccine.2008.12.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Revised: 12/04/2008] [Accepted: 12/05/2008] [Indexed: 11/30/2022]
Abstract
Orally administered recombinant Mycobacterium smegmatis (rM. smegmatis) vaccines represent an attractive option for mass vaccination programmes against various infectious diseases. Therefore, in the present study, we evaluated the capacity of the outer membrane protein 26kDa antigen (Omp26) of Helicobacter pylori (H. pylori) to induce therapeutic protection against H. pylori infection in mice. Omp26 was cloned and expressed in M. smegmatis mc(2)155 as a fusion with the Mycobacterium fortuitum beta-lactamase protein under the control of the up-regulated M. fortuitum beta-lactamase promoter, pBlaF. The rM. smegmatis strain was shown to be relatively stable in vitro in terms of plasmid stability and bacterial persistence. We found that oral immunization of H. pylori-infected mice with rM. smegmatis-Omp26 induced protection, i.e., significant reduction in bacterial colonization in the stomach. The protection was strongly related to serum specific antibodies with a Th(1) and Th(2) profile as well as to local cytokines in the stomach and spleen. These findings suggest that Omp26 is a promising vaccine candidate antigen for use in a therapeutic vaccine against H. pylori. The rM. smegmatis expressing Omp26 antigen could constitute an effective, low-cost combined vaccine against H. pylori.
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Affiliation(s)
- Lin Lü
- Department of Gastroenterology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
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A Replication-Limited Recombinant Mycobacterium bovis BCG vaccine against tuberculosis designed for human immunodeficiency virus-positive persons is safer and more efficacious than BCG. Infect Immun 2008; 76:5200-14. [PMID: 18725418 DOI: 10.1128/iai.00434-08] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Tuberculosis is the leading cause of death in AIDS patients, yet the current tuberculosis vaccine, Mycobacterium bovis bacillus Calmette-Guérin (BCG), is contraindicated for immunocompromised individuals, including human immunodeficiency virus-positive persons, because it can cause disseminated disease; moreover, its efficacy is suboptimal. To address these problems, we have engineered BCG mutants that grow normally in vitro in the presence of a supplement, are preloadable with supplement to allow limited growth in vivo, and express the highly immunoprotective Mycobacterium tuberculosis 30-kDa major secretory protein. The limited replication in vivo renders these vaccines safer than BCG in SCID mice yet is sufficient to induce potent cell-mediated and protective immunity in the outbred guinea pig model of pulmonary tuberculosis. In the case of one vaccine, rBCG(mbtB)30, protection was superior to that with BCG (0.3-log fewer CFU of M. tuberculosis in the lung [P < 0.04] and 0.6-log fewer CFU in the spleen [P = 0.001] in aerosol-challenged animals [means for three experiments]); hence, rBCG(mbtB)30 is the first live mycobacterial vaccine that is both more attenuated than BCG in the SCID mouse and more potent than BCG in the guinea pig. Our study demonstrates the feasibility of developing safer and more potent vaccines against tuberculosis. The novel approach of engineering a replication-limited vaccine expressing a recombinant immunoprotective antigen and preloading it with a required nutrient, such as iron, that is capable of being stored should be generally applicable to other live vaccine vectors targeting intracellular pathogens.
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Lee BY, Clemens DL, Horwitz MA. The metabolic activity of Mycobacterium tuberculosis, assessed by use of a novel inducible GFP expression system, correlates with its capacity to inhibit phagosomal maturation and acidification in human macrophages. Mol Microbiol 2008; 68:1047-60. [PMID: 18363792 DOI: 10.1111/j.1365-2958.2008.06214.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mycobacterium tuberculosis generally reside in phagosomes within human macrophages that resist maturation and acidification, but exhibit significant heterogeneity. In this study we have constructed an IPTG-inducible GFP expression system in M. tuberculosis to assess the relationship between the metabolic status of M. tuberculosis and the degree of phagosomal maturation. Using these recombinant bacteria, we have found that, in human macrophages, M. tuberculosis that respond to IPTG with expression of GFP fluorescence, and hence are metabolically active, reside in non-acidified phagosomes that have not fused with Texas red dextran pre-labelled lysosomes. In contrast, M. tuberculosis that fail to express GFP in response to IPTG, and hence are metabolically inactive, reside within acidified phagosomes that have fused with Texas red dextran labelled lysosomes. These studies demonstrate that metabolic activity of M. tuberculosis correlates strongly with phagosomal maturation and that the inducible GFP expression system is useful for assessing metabolic activity of intracellular M. tuberculosis.
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Affiliation(s)
- Bai-Yu Lee
- Division of Infectious Diseases, Department of Medicine, University of California-Los Angeles, School of Medicine, Center for Health Sciences, Los Angeles, CA 90095-1688, USA
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Horwitz MA. Recombinant BCG expressing Mycobacterium tuberculosis major extracellular proteins. Microbes Infect 2005; 7:947-54. [PMID: 15919223 DOI: 10.1016/j.micinf.2005.04.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2005] [Accepted: 03/03/2005] [Indexed: 11/28/2022]
Abstract
rBCG30, the first vaccine against tuberculosis demonstrated more potent than BCG in preclinical studies, is the prototype of a class of vaccines that utilize BCG as a host organism for expressing and secreting Mycobacterium tuberculosis major extracellular proteins. The vaccine is based on the concept that extracellular proteins of intracellular pathogens are key immunoprotective molecules. rBCG30, which expresses and secretes large amounts of the M. tuberculosis 30 kDa major secretory protein, is currently in human clinical trials.
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Affiliation(s)
- Marcus A Horwitz
- Department of Medicine, School of Medicine, University of California-Los Angeles, Los Angeles, CA 90095, USA.
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