1
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Sulman S, Shahid S, Khaliq A, Ambreen A, Khan IH, Cooper AM, Akhtar MW. Enhanced serodiagnostic potential of a fusion molecule consisting of Rv1793, Rv2628 and a truncated Rv2608 of Mycobacterium tuberculosis. PLoS One 2021; 16:e0258389. [PMID: 34767571 PMCID: PMC8589213 DOI: 10.1371/journal.pone.0258389] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 09/25/2021] [Indexed: 11/19/2022] Open
Abstract
Serodiagnosis of tuberculosis (TB) can be rapid, reliable and cost-effective if the issue of variable antibody responses of TB patients against different Mycobacterium tuberculosis (Mtb) antigens can be overcome by developing fusion proteins containing epitopes from multiple antigens of Mtb. In this study, Mtb antigens Rv1793, Rv2628, Rv2608 and a truncated variant produced by removing non-epitopic region from N-terminal of Rv2608 (tnRv2608), and the fusion protein Rv1793-Rv2628-tnRv2608 (TriFu64), were expressed in E. coli and purified. Plasma samples from TB patients characterized by sex, age and sputum/culture positivity, were used to compare the sensitivity of the single antigens with the fusion protein. Sensitivity of Rv1793, Rv2628 and Rv2608, was 27.8%, 39% and 36.3%, respectively. Truncation of Rv2608 increased sensitivity by approximately 35% in confirmed TB cases. Sensitivity of the fusion construct, TriFu64 increased to 66% with a specificity of 100%. Importantly, tnRv2608 was better able to detect sputum and culture negative patients, and this carried through to the fusion protein. We demonstrate that fusion of Mtb proteins ensures broad sensitivity across disease types, sex and age groups in a Pakistani population.
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Affiliation(s)
- Sadaf Sulman
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Saher Shahid
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Aasia Khaliq
- Armed Forces Institute of Pathology, Rawalpindi, Pakistan
| | - Atiqa Ambreen
- Department of Microbiology, Gulab Devi Hospital, Lahore, Pakistan
| | - Imran H. Khan
- Department of Pathology and Laboratory Medicine, University of California, Davis, California, United States of America
| | - Andrea M. Cooper
- Department of Respiratory Sciences, University of Leicester, Leicester, United Kingdom
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2
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Delogu G, Brennan MJ, Manganelli R. PE and PPE Genes: A Tale of Conservation and Diversity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1019:191-207. [PMID: 29116636 DOI: 10.1007/978-3-319-64371-7_10] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PE and PPE are two large families of proteins typical of mycobacteria whose structural genes in the Mycobacterium tuberculosis complex (MTBC) occupy about 7% of the total genome. The most ancestral PE and PPE proteins are expressed by genes that belong to the same operon and in most cases are found inserted in the esx clusters, encoding a type VII secretion system. Duplication and expansion of pe and ppe genes, coupled with intragenomic and intergenomic recombination events, led to the emergence of the polymorphic pe_pgrs and ppe_mptr genes in the MTBC genome. The role and function of these proteins, and particularly of the polymorphic subfamilies, remains elusive, although it is widely accepted that PE and PPE proteins may represent a specialized collection used by MTBC to interact with the complex host immune system of mammals. In this chapter, we summarize what has been discovered since the identification of these genes in 1998, focusing on M. tuberculosis genetic variability, host-pathogen interaction and TB pathogenesis.
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Affiliation(s)
- Giovanni Delogu
- Institute of Microbiology, Università Cattolica del Sacro Cuore, Largo A. Gemelli, 8, 00168, Rome, Italy.
| | | | - Riccardo Manganelli
- Department of Molecular Medicine, University of Padua, Via A. Gabelli, 63, 35121, Padua, Italy
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3
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Dowall SD, Buttigieg KR, Findlay-Wilson SJD, Rayner E, Pearson G, Miloszewska A, Graham VA, Carroll MW, Hewson R. A Crimean-Congo hemorrhagic fever (CCHF) viral vaccine expressing nucleoprotein is immunogenic but fails to confer protection against lethal disease. Hum Vaccin Immunother 2016; 12:519-27. [PMID: 26309231 PMCID: PMC5049717 DOI: 10.1080/21645515.2015.1078045] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Crimean-Congo Hemorrhagic Fever (CCHF) is a severe tick-borne disease, endemic in many countries in Africa, the Middle East, Eastern Europe and Asia. Between 15–70% of reported cases are fatal with no approved vaccine available. In the present study, the attenuated poxvirus vector, Modified Vaccinia virus Ankara, was used to develop a recombinant candidate vaccine expressing the CCHF virus nucleoprotein. Cellular and humoral immunogenicity was confirmed in 2 mouse strains, including type I interferon receptor knockout mice, which are susceptible to CCHF disease. Despite the immune responses generated post-immunisation, the vaccine failed to protect animals from lethal disease in a challenge model.
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Affiliation(s)
- S D Dowall
- a Public Health England ; Porton Down; Salisbury , Wiltshire , UK
| | - K R Buttigieg
- a Public Health England ; Porton Down; Salisbury , Wiltshire , UK
| | | | - E Rayner
- a Public Health England ; Porton Down; Salisbury , Wiltshire , UK
| | - G Pearson
- a Public Health England ; Porton Down; Salisbury , Wiltshire , UK
| | - A Miloszewska
- a Public Health England ; Porton Down; Salisbury , Wiltshire , UK
| | - V A Graham
- a Public Health England ; Porton Down; Salisbury , Wiltshire , UK
| | - M W Carroll
- a Public Health England ; Porton Down; Salisbury , Wiltshire , UK
| | - R Hewson
- a Public Health England ; Porton Down; Salisbury , Wiltshire , UK
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4
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Tuberculosis vaccines--state of the art, and novel approaches to vaccine development. Int J Infect Dis 2016; 32:5-12. [PMID: 25809749 DOI: 10.1016/j.ijid.2014.11.026] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 11/21/2014] [Accepted: 11/25/2014] [Indexed: 11/20/2022] Open
Abstract
The quest for a vaccine that could have a major impact in reducing the current global burden of TB disease in humans continues to be extremely challenging. Significant gaps in our knowledge and understanding of the pathogenesis and immunology of tuberculosis continue to undermine efforts to break new ground, and traditional approaches to vaccine development have thus far met with limited success. Existing and novel candidate vaccines are being assessed in the context of their ability to impact the various stages that culminate in disease transmission and an increase in the global burden of disease. Innovative methods of vaccine administration and delivery have provided a fresh stimulus to the search for the elusive vaccine. Here we discuss the current status of preclinical vaccine development, providing insights into alternative approaches to vaccine delivery and promising candidate vaccines. The state of the art of clinical development also is reviewed.
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5
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Immunoinformatics study on highly expressed Mycobacterium tuberculosis genes during infection. Tuberculosis (Edinb) 2014; 94:475-81. [DOI: 10.1016/j.tube.2014.06.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 06/04/2014] [Accepted: 06/08/2014] [Indexed: 12/22/2022]
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6
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Buttigieg KR, Dowall SD, Findlay-Wilson S, Miloszewska A, Rayner E, Hewson R, Carroll MW. A novel vaccine against Crimean-Congo Haemorrhagic Fever protects 100% of animals against lethal challenge in a mouse model. PLoS One 2014; 9:e91516. [PMID: 24621656 PMCID: PMC3951450 DOI: 10.1371/journal.pone.0091516] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 02/10/2014] [Indexed: 12/21/2022] Open
Abstract
Crimean-Congo Haemorrhagic Fever (CCHF) is a severe tick-borne disease, endemic in many countries in Africa, the Middle East, Eastern Europe and Asia. Between 15-70% of reported cases are fatal. There is no approved vaccine available, and preclinical protection in vivo by an experimental vaccine has not been demonstrated previously. In the present study, the attenuated poxvirus vector, Modified Vaccinia virus Ankara, was used to develop a recombinant candidate vaccine expressing the CCHF virus glycoproteins. Cellular and humoral immunogenicity was confirmed in two mouse strains, including type I interferon receptor knockout mice, which are susceptible to CCHF disease. This vaccine protected all recipient animals from lethal disease in a challenge model adapted to represent infection via a tick bite. Histopathology and viral load analysis of protected animals confirmed that they had been exposed to challenge virus, even though they did not exhibit clinical signs. This is the first demonstration of efficacy of a CCHF vaccine.
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MESH Headings
- Animals
- Cell Line
- Cricetinae
- DNA, Recombinant/genetics
- Disease Models, Animal
- Female
- Glycoproteins/genetics
- Glycoproteins/immunology
- Hemorrhagic Fever Virus, Crimean-Congo/immunology
- Hemorrhagic Fever Virus, Crimean-Congo/physiology
- Hemorrhagic Fever, Crimean/immunology
- Hemorrhagic Fever, Crimean/metabolism
- Hemorrhagic Fever, Crimean/pathology
- Hemorrhagic Fever, Crimean/prevention & control
- Immunity, Cellular
- Immunity, Humoral
- Mice
- Plasmids/genetics
- Receptor, Interferon alpha-beta/deficiency
- Receptors, Interferon/deficiency
- Viral Load
- Viral Proteins/genetics
- Viral Proteins/immunology
- Viral Vaccines/genetics
- Viral Vaccines/immunology
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Affiliation(s)
- Karen R. Buttigieg
- Microbiology Services Research, Public Health England, Porton Down, Wiltshire, United Kingdom
| | - Stuart D. Dowall
- Microbiology Services Research, Public Health England, Porton Down, Wiltshire, United Kingdom
| | - Stephen Findlay-Wilson
- Microbiology Services Research, Public Health England, Porton Down, Wiltshire, United Kingdom
| | - Aleksandra Miloszewska
- Microbiology Services Research, Public Health England, Porton Down, Wiltshire, United Kingdom
| | - Emma Rayner
- Microbiology Services Research, Public Health England, Porton Down, Wiltshire, United Kingdom
| | - Roger Hewson
- Microbiology Services Research, Public Health England, Porton Down, Wiltshire, United Kingdom
| | - Miles W. Carroll
- Microbiology Services Research, Public Health England, Porton Down, Wiltshire, United Kingdom
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7
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Singh SK, Kumari R, Singh DK, Tiwari S, Singh PK, Sharma S, Srivastava KK. Putative roles of a proline–glutamic acid-rich protein (PE3) in intracellular survival and as a candidate for subunit vaccine against Mycobacterium tuberculosis. Med Microbiol Immunol 2013; 202:365-77. [DOI: 10.1007/s00430-013-0299-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 05/10/2013] [Indexed: 10/26/2022]
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8
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Singh SK, Tripathi DK, Singh PK, Sharma S, Srivastava KK. Protective and survival efficacies of Rv0160c protein in murine model of Mycobacterium tuberculosis. Appl Microbiol Biotechnol 2012; 97:5825-37. [PMID: 23104642 DOI: 10.1007/s00253-012-4493-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 10/01/2012] [Accepted: 10/02/2012] [Indexed: 12/20/2022]
Abstract
The proline-glutamic acid (PE) and proline-proline-glutamic acid (PPE) multi-gene families code for approximately 10% of the Mycobacterium tuberculosis (Mtb) genome. These proteins are thought to be virulence factors that participate in impounding the host immune responses. While some members have been studied, the functions of most PE/PPE proteins are yet to be explored. The studies presented here have specifically characterized the roles of one of the PE proteins of Mtb, Rv0160c (PE4), in mycobacterial persistence and in prophylactic efficacy. We have expressed Rv0160c in a non-pathogenic fast-growing Mycobacterium smegmatis strain and demonstrated that the protein improves the survival of mycobacteria in macrophages and in mice. The protein has also shown its effect under physiological stress of bacteria, as evidenced by elevated expression in acidic and in hypoxic conditions. In mice, the level of Rv0160c was noticeably high during the chronic stage of tuberculosis. The seroreactivity of the protein against different categories of tuberculosis patients revealed a strong B-cell humoral response in freshly infected pulmonary tuberculosis patients. In mice, it exhibited increased IL-2, TNF, and IL-6 production. The antigenic properties of the protein directed towards the protective efficacy against the Mtb challenge. All together, our findings have identified Rv0160c as an in vivo expressed immunodominant antigen which plays a crucial role in the pathogenesis of mycobacterial disease and could prove to be a good preventive antigen for tuberculosis.
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Affiliation(s)
- Susmita K Singh
- Division of Microbiology, CSIR--Central Drug Research Institute, Lucknow 226001, India
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9
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Lu Y, Xu Y, Yang E, Wang C, Wang H, Shen H. Novel recombinant BCG coexpressing Ag85B, ESAT-6 and Rv2608 elicits significantly enhanced cellular immune and antibody responses in C57BL/6 mice. Scand J Immunol 2012; 76:271-7. [PMID: 22671973 DOI: 10.1111/j.1365-3083.2012.02726.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tuberculosis (TB) remains an enormous global health problem, and a new vaccine against TB more potent than the current inadequate vaccine, the Bacille Calmette-Guérin (BCG), is urgently needed. BCG has proven to be an effective recombinant delivery vehicle for foreign antigens because of its ability to induce long-lived specific humoral and cellular immunity. Experimental evidences have revealed that Ag85B, ESAT-6 and Rv2608 are important immunodominant antigens of Mycobacterium tuberculosis and are all promising vaccine candidate molecules. In this study, we have constructed a novel recombinant BCG (rBCG) expressing fusion protein Ag85B-ESAT6-Rv2608 and evaluated the immunogenicity of rBCG in C57BL/6 mice. Results show there is strong TB-specific CD4⁺ and CD8⁺ T lymphocytes proliferative response in mice immunized with rBCG vaccine, especially the cytotoxic CD8⁺ T cells playing an important role in protection against TB. And rBCG immunization has induced a significantly strong Th1 immune response, characterized by the increased ratio of IgG2b/IgG1. Results also show that rBCG immunization could increase the secretion of Th1 cytokines such as TNF-α and IL-2 and could decrease the secretion of Th2 cytokine IL-10. Moreover, it was shown that rBCG immunization induced a strong humoral response in mice, characterized by the elevated IgG titre. Therefore, we conclude that this rBCG immunization could increase both cellular immune response and antigen-specific humoral response significantly as compared to BCG immunization in mice. The above results illustrated that rBCG::Ag85B-ESAT6-Rv2608 is a potential candidate against M. tuberculosis for further study.
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Affiliation(s)
- Y Lu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
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10
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McEvoy CRE, Cloete R, Müller B, Schürch AC, van Helden PD, Gagneux S, Warren RM, Gey van Pittius NC. Comparative analysis of Mycobacterium tuberculosis pe and ppe genes reveals high sequence variation and an apparent absence of selective constraints. PLoS One 2012; 7:e30593. [PMID: 22496726 PMCID: PMC3319526 DOI: 10.1371/journal.pone.0030593] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 12/19/2011] [Indexed: 11/18/2022] Open
Abstract
Mycobacterium tuberculosis complex (MTBC) genomes contain 2 large gene families termed pe and ppe. The function of pe/ppe proteins remains enigmatic but studies suggest that they are secreted or cell surface associated and are involved in bacterial virulence. Previous studies have also shown that some pe/ppe genes are polymorphic, a finding that suggests involvement in antigenic variation. Using comparative sequence analysis of 18 publicly available MTBC whole genome sequences, we have performed alignments of 33 pe (excluding pe_pgrs) and 66 ppe genes in order to detect the frequency and nature of genetic variation. This work has been supplemented by whole gene sequencing of 14 pe/ppe (including 5 pe_pgrs) genes in a cohort of 40 diverse and well defined clinical isolates covering all the main lineages of the M. tuberculosis phylogenetic tree. We show that nsSNP's in pe (excluding pgrs) and ppe genes are 3.0 and 3.3 times higher than in non-pe/ppe genes respectively and that numerous other mutation types are also present at a high frequency. It has previously been shown that non-pe/ppe M. tuberculosis genes display a remarkably low level of purifying selection. Here, we also show that compared to these genes those of the pe/ppe families show a further reduction of selection pressure that suggests neutral evolution. This is inconsistent with the positive selection pressure of "classical" antigenic variation. Finally, by analyzing such a large number of genes we were able to detect large differences in mutation type and frequency between both individual genes and gene sub-families. The high variation rates and absence of selective constraints provides valuable insights into potential pe/ppe function. Since pe/ppe proteins are highly antigenic and have been studied as potential vaccine components these results should also prove informative for aspects of M. tuberculosis vaccine design.
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Affiliation(s)
- Christopher R E McEvoy
- Department of Science and Technology, Medical Research Council Centre for Molecular and Cellular Biology, Stellenbosch University, Tygerberg, Cape Town, South Africa.
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11
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Hanif SNM, Al-Attiyah R, Mustafa AS. Cellular immune responses in mice induced by M. tuberculosis PE35-DNA vaccine construct. Scand J Immunol 2011; 74:554-60. [PMID: 21812801 DOI: 10.1111/j.1365-3083.2011.02604.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The PE35 (Rv3872) gene of Mycobacterium tuberculosis is present in the region of difference (RD) one that is deleted in all vaccine strains of Mycobacterium bovis bacillus Calmette Guerin. The aim of this study was to clone PE35 DNA into a DNA vaccine plasmid with CMV promoter and interleukin-2 secretory signal and evaluate the recombinant plasmid for induction of antigen-specific cellular responses in mice. DNA corresponding to PE35 was PCR amplified from the genomic DNA of M. tuberculosis H(37) Rv, cloned into pGEMT-Easy vector and sub-cloned into the DNA vaccine vector pUMVC6. BALB/c mice were immunized with recombinant pUMVC6/PE35 and spleen cells were tested for T-helper (Th)1-type (antigen-induced proliferation and secretion of IFN-γ) and Th2-type (IL-5), and anti-inflammatory (IL-10) cytokine responses to pure recombinant PE35 protein and its synthetic peptides. Mice immunized with the recombinant plasmid DNA (pUMVC6/PE35) showed positive Th1-type cellular responses to pure PE35, but not to an irrelevant antigen, i.e. PPE68 (Rv3873). However, the vaccine construct did not induce antigen-specific Th2-type (IL-5) or anti-inflammatory (IL-10) reactivity to PE35. Testing with synthetic peptides showed that Th1-type cells recognizing various epitopes of PE35 were induced in mice immunized with pUMVC6/PE35 DNA. These results suggest that pUMVC6/PE35 may be useful as a safer vaccine candidate against TB.
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Affiliation(s)
- S N M Hanif
- Faculty of Medicine, Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait.
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12
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Mycobacterial PE/PPE proteins at the host-pathogen interface. Clin Dev Immunol 2011; 2011:497203. [PMID: 21318182 PMCID: PMC3034920 DOI: 10.1155/2011/497203] [Citation(s) in RCA: 192] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 12/23/2010] [Indexed: 11/17/2022]
Abstract
The mycobacterial PE/PPE proteins have attracted much interest since their formal identification just over a decade ago. It has been widely speculated that these proteins may play a role in evasion of host immune responses, possibly via antigenic variation. Although a cohesive understanding of their function(s) has yet to be established, emerging data increasingly supports a role for the PE/PPE proteins at multiple levels of the infectious process. This paper will delineate salient features of the families revealed by comparative genomics, bioinformatic analyses and genome-wide screening approaches and will summarise existing knowledge of subcellular localization, secretion pathways, and protein structure. These characteristics will be considered in light of findings on innate and adaptive host responses to PE/PPE proteins, and we will review the increasing body of data on B and T cell recognition of these proteins. Finally, we will consider how current knowledge and future explorations may contribute to a more comprehensive understanding of these intriguing proteins and their involvement in host pathogen interactions. Ultimately this information could underpin future intervention strategies, for example, in the area of new and improved diagnostic tools and vaccine candidates.
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13
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Zhang H, Peng P, Miao S, Zhao Y, Mao F, Wang L, Bai Y, Xu Z, Wei S, Shi C. Recombinant Mycobacterium smegmatis expressing an ESAT6-CFP10 fusion protein induces anti-mycobacterial immune responses and protects against Mycobacterium tuberculosis challenge in mice. Scand J Immunol 2010; 72:349-57. [PMID: 20883320 DOI: 10.1111/j.1365-3083.2010.02448.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The currently used vaccine against tuberculosis, Bacille Calmette-Guérin (BCG), has variable efficacy, so new vaccine development is crucial. In this study, we evaluated a recombinant vaccine prepared from non-pathogenic Mycobacterium smegmatis (rMS) that expresses a fusion of early secreted antigenic target 6-kDa antigen (ESAT6) and culture filtrate protein 10 (CFP10). C57BL/6 mice were immunized with the rMS expressing the ESAT6-CFP10 fusion protein (rM.S-e6c10) or with BCG. The mice in the rM.S-e6c10 group had a significantly higher titre of anti-ESAT6-CFP10 antibodies than did animals in the BCG or saline groups. Spleen cells from rM.S-e6c10-immunized mice exhibited a cytotoxic response to ESAT6 and CFP10-expressed target cells, but spleen cells from animals in the other groups did not. Levels of IFN-γ and IL-2 production by purified T cells from spleens were significantly higher in rM.S-e6c10 group than in BCG group. Finally, after M. tuberculosis (MTB)-challenged mice, dramatic reduction in the numbers of MTB colony-forming units (CFUs) in the lungs was observed for the mice immunized with the rMS. The protective efficacy of rM.S-e6c10 and BCG vaccination was similar based on measures of MTB burden and lung pathology. Our data indicate that the recombinant M. smegmatis vaccine expressing the ESAT6-CFP10 fusion protein has potential in clinic application.
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Affiliation(s)
- H Zhang
- Laboratory Animal Center, Fourth Military Medical University, Xi'an, China
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14
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Abstract
Batch cultures have predominately been used for the study of physiology and gene expression in mycobacteria. This chapter describes the assembly of chemostats and the methodology that is being used for growing Mycobacterium tuberculosis in continuous culture, which provides the greatest control over experimental conditions. It is difficult to determine the underlying genetic changes that enable M. tuberculosis to adapt to the host environment, but in vitro experiments aid the interpretation of gene expression profiles of the bacillus in vivo. Selecting relevant host conditions for study presents a major challenge. Oxygen availability has been identified as an important environmental stimulus and is a simple parameter to adjust and monitor. Described here are continuous culture methods to determine the response of M. tuberculosis to low oxygen environments.
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Affiliation(s)
- Joanna Bacon
- TB Research, Health Protection Agency, CEPR, Porton Down, Salisbury SP4 OJG, UK.
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15
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Williams A, Hall Y, Orme IM. Evaluation of new vaccines for tuberculosis in the guinea pig model. Tuberculosis (Edinb) 2009; 89:389-97. [PMID: 19815462 DOI: 10.1016/j.tube.2009.08.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 08/17/2009] [Indexed: 11/30/2022]
Abstract
The guinea pig is a very useful animal model for evaluating new tuberculosis candidate vaccines. In addition to established methods for bacterial load determinations, new technologies are emerging that allow us to specifically evaluate effects of vaccines on the pathology of the disease process and the expression by the host of cell mediated immunity. Limitations to the model include housing and related costs, which often contribute to issue with study design and adequate statistical power, and the use of laboratory strains of Mycobacterium tuberculosis which lack the high virulence and immune evasion properties of newly emerging clinical isolates.
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Affiliation(s)
- Ann Williams
- Health Protection Agency, Centre for Emergency Preparedness and Response, Porton Down, Salisbury, Wiltshire, UK
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16
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Bertholet S, Ireton GC, Kahn M, Guderian J, Mohamath R, Stride N, Laughlin EM, Baldwin SL, Vedvick TS, Coler RN, Reed SG. Identification of human T cell antigens for the development of vaccines against Mycobacterium tuberculosis. THE JOURNAL OF IMMUNOLOGY 2008; 181:7948-57. [PMID: 19017986 DOI: 10.4049/jimmunol.181.11.7948] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Development of a subunit vaccine for Mycobacterium tuberculosis (Mtb) depends on the identification of Ags that induce appropriate T cell responses. Using bioinformatics, we selected a panel of 94 Mtb genes based on criteria that included growth in macrophages, up- or down-regulation under hypoxic conditions, secretion, membrane association, or because they were members of the PE/PPE or EsX families. Recombinant proteins encoded by these genes were evaluated for IFN-gamma recall responses using PBMCs from healthy subjects previously exposed to Mtb. From this screen, dominant human T cell Ags were identified and 49 of these proteins, formulated in CpG, were evaluated as vaccine candidates in a mouse model of tuberculosis. Eighteen of the individual Ags conferred partial protection against challenge with virulent Mtb. A combination of three of these Ags further increased protection against Mtb to levels comparable to those achieved with bacillus Calmette-Guérin vaccination. Vaccine candidates that led to reduction in lung bacterial burden following challenge-induced pluripotent CD4 and CD8 T cells, including Th1 cell responses characterized by elevated levels of Ag-specific IgG2c, IFN-gamma, and TNF. Priority vaccine Ags elicited pluripotent CD4 and CD8 T responses in purified protein derivative-positive donor PBMCs. This study identified numerous novel human T cell Ags suitable to be included in subunit vaccines against tuberculosis.
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Abstract
Johne's disease, or paratuberculosis, is a chronic granulomatous enteritis in ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP) affecting principally cattle, sheep and goats. Primarily, there are two clinical signs: cachexia and chronic diarrhea (less common in goats and sheep). This disease results in considerable economic losses in livestock industry, particularly the dairy sector. The route of transmission is mostly by the fecal-oral route, but hygienic measures and culling of shedding animals are not sufficient to eradicate this disease. Moreover, diagnostic tools available at this moment are not powerful enough to perform early and specific diagnosis. Existing vaccines, based on whole killed or live-attenuated bacteria, can delay the onset of clinical symptoms but do not protect against infection. Moreover, vaccinated animals develop antibodies that interfere with existing serodiagnostic tests for paratuberculosis and they become reactive in the tuberculin skin test, used for the control of bovine tuberculosis. This review summarizes the current knowledge of the immune responses induced by MAP infection, with focus on cattle studies. It provides an overview of the existing MAP vaccines and comments on the development of second-generation subunit vaccines based on new technologies.
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Affiliation(s)
- Valérie Rosseels
- WIV-Pasteur Institute Brussels, Laboratory of Mycobacterial Immunology, 642 Engelandstraat, B1180 Brussels, Belgium.
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Zvi A, Ariel N, Fulkerson J, Sadoff JC, Shafferman A. Whole genome identification of Mycobacterium tuberculosis vaccine candidates by comprehensive data mining and bioinformatic analyses. BMC Med Genomics 2008; 1:18. [PMID: 18505592 PMCID: PMC2442614 DOI: 10.1186/1755-8794-1-18] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Accepted: 05/28/2008] [Indexed: 12/19/2022] Open
Abstract
Background Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), infects ~8 million annually culminating in ~2 million deaths. Moreover, about one third of the population is latently infected, 10% of which develop disease during lifetime. Current approved prophylactic TB vaccines (BCG and derivatives thereof) are of variable efficiency in adult protection against pulmonary TB (0%–80%), and directed essentially against early phase infection. Methods A genome-scale dataset was constructed by analyzing published data of: (1) global gene expression studies under conditions which simulate intra-macrophage stress, dormancy, persistence and/or reactivation; (2) cellular and humoral immunity, and vaccine potential. This information was compiled along with revised annotation/bioinformatic characterization of selected gene products and in silico mapping of T-cell epitopes. Protocols for scoring, ranking and prioritization of the antigens were developed and applied. Results Cross-matching of literature and in silico-derived data, in conjunction with the prioritization scheme and biological rationale, allowed for selection of 189 putative vaccine candidates from the entire genome. Within the 189 set, the relative distribution of antigens in 3 functional categories differs significantly from their distribution in the whole genome, with reduction in the Conserved hypothetical category (due to improved annotation) and enrichment in Lipid and in Virulence categories. Other prominent representatives in the 189 set are the PE/PPE proteins; iron sequestration, nitroreductases and proteases, all within the Intermediary metabolism and respiration category; ESX secretion systems, resuscitation promoting factors and lipoproteins, all within the Cell wall category. Application of a ranking scheme based on qualitative and quantitative scores, resulted in a list of 45 best-scoring antigens, of which: 74% belong to the dormancy/reactivation/resuscitation classes; 30% belong to the Cell wall category; 13% are classical vaccine candidates; 9% are categorized Conserved hypotheticals, all potentially very potent T-cell antigens. Conclusion The comprehensive literature and in silico-based analyses allowed for the selection of a repertoire of 189 vaccine candidates, out of the whole-genome 3989 ORF products. This repertoire, which was ranked to generate a list of 45 top-hits antigens, is a platform for selection of genes covering all stages of M. tuberculosis infection, to be incorporated in rBCG or subunit-based vaccines.
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Affiliation(s)
- Anat Zvi
- Israel Institute for Biological Research, Ness Ziona 74100, Israel.
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Wang JL, Qie YQ, Zhu BD, Zhang HM, Xu Y, Wang QZ, Chen JZ, Liu W, Wang HH. Evaluation of a recombinant BCG expressing antigen Ag85B and PPE protein Rv3425 from DNA segment RD11 of Mycobacterium tuberculosis in C57BL/6 mice. Med Microbiol Immunol 2008; 198:5-11. [PMID: 18491134 DOI: 10.1007/s00430-008-0098-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Indexed: 11/25/2022]
Abstract
Antigen 85B (Ag85B) is an important immunodominant antigen of Mycobacterium tuberculosis, and is a very promising vaccine candidate molecule. Rv3425 is a member of the subgroup 3 of the PPE family, which does not exist in all BCG strains. In this study we constructed a new rBCG which included this united gene (Ag85B-Rv3425). The level of antigen-stimulated T cells expressing IFN-gamma was significantly higher in the C57BL/6 mice vaccinated with rBCG::Ag85B-Rv3425 than with BCG. In addition, the sera from mice immunized with rBCG::Ag85B-Rv3425 revealed an increase in the specific immunoglobulin G titers than that from mice immunized with BCG. Antigen specific IgG subclass analysis showed that rBCG::Ag85B-Rv3425 tended to facilitate IgG2a production, suggesting enhancement of predominant Th1 response which in turn may facilitate increased production of protective IFN-gamma. These results suggested that this rBCG::Ag85B-Rv3425 could be a strong vaccine candidate for further study.
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Affiliation(s)
- Jiu ling Wang
- Institute of Genetics, Fudan University, 200433, Shanghai, People's Republic of China
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