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Roe SK, Zhu T, Slepenkin A, Berges A, Fairman J, de la Maza LM, Massari P. Structural Assessment of Chlamydia trachomatis Major Outer Membrane Protein (MOMP)-Derived Vaccine Antigens and Immunological Profiling in Mice with Different Genetic Backgrounds. Vaccines (Basel) 2024; 12:789. [PMID: 39066427 PMCID: PMC11281497 DOI: 10.3390/vaccines12070789] [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: 06/20/2024] [Revised: 07/13/2024] [Accepted: 07/16/2024] [Indexed: 07/28/2024] Open
Abstract
Chlamydia trachomatis (Ct) is the most common cause of bacterial sexually transmitted infections (STIs) worldwide. Ct infections are often asymptomatic in women, leading to severe reproductive tract sequelae. Development of a vaccine against Chlamydia is crucial. The Chlamydia major outer membrane protein (MOMP) is a prime vaccine antigen candidate, and it can elicit both neutralizing antibodies and protective CD4+ T cell responses. We have previously designed chimeric antigens composed of immunogenic variable regions (VDs) and conserved regions (CDs) of MOMP from Chlamydia muridarum (Cm) expressed into a carrier protein (PorB), and we have shown that these were protective in a mouse model of Cm respiratory infection. Here, we generated corresponding constructs based on MOMP from Ct serovar F. Preliminary structure analysis of the three antigens, PorB/VD1-3, PorB/VD1-4 and PorB/VD1-2-4, showed that they retained structure features consistent with those of PorB. The antigens induced robust humoral and cellular responses in mice with different genetic backgrounds. The antibodies were cross-reactive against Ct, but only anti-PorB/VD1-4 and anti-PorB/VD1-2-4 IgG antibodies were neutralizing, likely due to the antigen specificity. The cellular responses included proliferation in vitro and production of IFN-γ by splenocytes following Ct re-stimulation. Our results support further investigation of the PorB/VD antigens as potential protective candidates for a Chlamydia subunit vaccine.
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Affiliation(s)
- Shea K. Roe
- Department of Immunology, Tufts University School of Medicine, Boston, MA 02111, USA; (S.K.R.)
| | - Tianmou Zhu
- Department of Immunology, Tufts University School of Medicine, Boston, MA 02111, USA; (S.K.R.)
| | - Anatoli Slepenkin
- Department of Pathology and Laboratory Medicine, University of California, Irvine, CA 92697, USA (L.M.d.l.M.)
| | - Aym Berges
- Vaxcyte Inc., 825 Industrial Road, Suite 300, San Carlos, CA 94070, USA (J.F.)
| | - Jeff Fairman
- Vaxcyte Inc., 825 Industrial Road, Suite 300, San Carlos, CA 94070, USA (J.F.)
| | - Luis M. de la Maza
- Department of Pathology and Laboratory Medicine, University of California, Irvine, CA 92697, USA (L.M.d.l.M.)
| | - Paola Massari
- Department of Immunology, Tufts University School of Medicine, Boston, MA 02111, USA; (S.K.R.)
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Rosenkrands I, Olsen AW, Knudsen S, Dehari N, Juel HB, Cheeseman HM, Andersen P, Shattock RJ, Follmann F. Human antibody signatures towards the Chlamydia trachomatis major outer membrane protein after natural infection and vaccination. EBioMedicine 2024; 104:105140. [PMID: 38744110 PMCID: PMC11108849 DOI: 10.1016/j.ebiom.2024.105140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 03/07/2024] [Accepted: 04/16/2024] [Indexed: 05/16/2024] Open
Abstract
BACKGROUND Chlamydia trachomatis (CT) Major Outer Membrane Protein (MOMP) holds a neutralising epitope in the Variable Domain 4 (VD4), and this region's immune dominance during infection is well known. This study aimed to assess the antibody response induced after infection and compare it for specificity and functionality to the response following vaccination with the vaccine CTH522, which contains VD4's from serovars D, E, F, and G. METHODS We assessed the antibody epitopes in MOMP by a high density peptide array. Furthermore, the role of the VD4 epitope in neutralisation was explored by competitive inhibition experiments with a fusion protein holding the neutralising VD4 linear epitope. This was done in two independent groups: 1) MOMP seropositive individuals infected with CT (n = 10, from case-control study) and 2) CTH522/CAF®01-vaccinated females (n = 14) from the CHLM-01 clinical trial. FINDINGS We identified the major antigenic regions in MOMP as VD4 and the conserved region just before VD3 in individuals infected with CT. The same regions, with the addition of VD1, were identified in vaccine recipients. Overall, the VD4 peptide responses were uniform in vaccinated individuals and led to inhibition of infection in vitro in all tested samples, whereas the VD4 responses were more heterogenous in individuals infected with CT, and only 2 out of 10 samples had VD4-mediated neutralising antibody responses. INTERPRETATION These data provide insights into the role of antibodies against MOMP VD4 induced after infection and vaccination, and show that their functionality differs. The induction of functional VD4-specific antibodies in vaccine recipients mimics previous results from animal models. FUNDING This work was supported by the European Commission through contract FP7-HEALTH-2011.1.4-4-280873 (ADITEC) and Fonden til Lægevidenskabens Fremme.
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Affiliation(s)
- Ida Rosenkrands
- Center for Vaccine Research, Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark.
| | - Anja W Olsen
- Center for Vaccine Research, Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark
| | - Sara Knudsen
- Center for Vaccine Research, Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark
| | - Nida Dehari
- Center for Vaccine Research, Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark
| | - Helene Bæk Juel
- Center for Vaccine Research, Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark
| | - Hannah M Cheeseman
- Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Peter Andersen
- Center for Vaccine Research, Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark; Novo Nordisk Fonden, Hellerup, Denmark
| | - Robin J Shattock
- Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Frank Follmann
- Center for Vaccine Research, Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark
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3
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Olsen AW, Rosenkrands I, Jacobsen CS, Cheeseman HM, Kristiansen MP, Dietrich J, Shattock RJ, Follmann F. Immune signature of Chlamydia vaccine CTH522/CAF®01 translates from mouse-to-human and induces durable protection in mice. Nat Commun 2024; 15:1665. [PMID: 38396019 PMCID: PMC10891140 DOI: 10.1038/s41467-024-45526-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 01/10/2024] [Indexed: 02/25/2024] Open
Abstract
The clinical development of an effective Chlamydia vaccine requires in-depth understanding of how well protective pre-clinical immune signatures translate to humans. Here, we report a comparative immunological characterization of CTH522/CAF®01 in female mice and humans. We find a range of immune signatures that translate from mouse to human, including a Th1/Th17 cytokine profile and antibody functionality. We identify vaccine-induced T cell epitopes, conserved among Chlamydia serovars, and previously found in infected individuals. Using the mouse model, we show that the common immune signature protected against ascending infection in mice, and vaccine induced antibodies could delay bacterial ascension to the oviduct, as well as development of pathology, in a T cell depleted mouse model. Finally, we demonstrate long-lasting immunity and protection of mice one year after vaccination. Based on the results obtained in the present study, we propose to further investigate CTH522/CAF®01 in a phase IIb study.
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Affiliation(s)
- Anja W Olsen
- Center for Vaccine Research, Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark.
| | - Ida Rosenkrands
- Center for Vaccine Research, Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark
| | - Christina S Jacobsen
- Center for Vaccine Research, Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark
- PharmaRelations, Virum, Denmark
| | | | - Max P Kristiansen
- Center for Vaccine Research, Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark
| | - Jes Dietrich
- Center for Vaccine Research, Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark
| | - Robin J Shattock
- Department of Infectious Disease, Imperial College London, London, UK
| | - Frank Follmann
- Center for Vaccine Research, Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark
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4
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Martínez-García L, Orviz E, González-Alba JM, Comunión A, Puerta T, Mateo M, Sánchez-Conde M, Rodríguez-Jiménez MC, Rodríguez-Domínguez M, Bru-Gorraiz FJ, del Romero J, Cantón R, Galán JC. Rapid expansion of lymphogranuloma venereum infections with fast diversification and spread of Chlamydia trachomatis L genovariants. Microbiol Spectr 2024; 12:e0285523. [PMID: 38095475 PMCID: PMC10783107 DOI: 10.1128/spectrum.02855-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 11/22/2023] [Indexed: 01/13/2024] Open
Abstract
IMPORTANCE Numerous international organizations, including the World Health Organization, have been drawing attention to the global increase in sexually transmitted infections. Twenty years ago, lymphogranuloma venereum (LGV) was mainly considered a tropical disease; in recent decades, however, LGV has been increasingly present in high-income countries. This increase has been linked to men who have sex with men who participate in highly interconnected sexual networks, leading to a rapid spread of LGV. This study focuses on the spread of LGV, presenting the largest time series of LGV prevalence in Spain, which includes more than a thousand diagnosed cases in one large city. The number of LGV cases diagnosed was analyzed over time, and a selection of strains was subjected to molecular genotyping. The results indicate that the LGV epidemic is gradually evolving toward an increasingly complex diversification due to the selection of successful genovariants that have emerged by mutation and recombination events, suggesting that we are moving toward an unpredictable scenario.
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Affiliation(s)
- Laura Martínez-García
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- Centro de Investigación Biomédica en Red en Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Eva Orviz
- Centro Sanitario Sandoval, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria San Carlos (IdISSC), Madrid, Spain
| | - José María González-Alba
- Servicio de Microbiología, Hospital Universitario Central de Asturias, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | | | - Teresa Puerta
- Centro Sanitario Sandoval, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria San Carlos (IdISSC), Madrid, Spain
| | - María Mateo
- Servicio de Microbiología, Hospital Central de la Defensa Gómez-Ulla, Madrid, Spain
| | - Matilde Sánchez-Conde
- Servicio de Enfermedades Infecciosas, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- Centro de Investigación Biomédica en Red en Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - María Concepción Rodríguez-Jiménez
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Mario Rodríguez-Domínguez
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- Centro de Investigación Biomédica en Red en Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | | | - Jorge del Romero
- Centro Sanitario Sandoval, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria San Carlos (IdISSC), Madrid, Spain
| | - Rafael Cantón
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- Centro de Investigación Biomédica en Red en Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Juan Carlos Galán
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- Centro de Investigación Biomédica en Red en Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
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5
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Seth-Smith HMB, Bénard A, Bruisten SM, Versteeg B, Herrmann B, Kok J, Carter I, Peuchant O, Bébéar C, Lewis DA, Puerta T, Keše D, Balla E, Zákoucká H, Rob F, Morré SA, de Barbeyrac B, Galán JC, de Vries HJC, Thomson NR, Goldenberger D, Egli A. Ongoing evolution of Chlamydia trachomatis lymphogranuloma venereum: exploring the genomic diversity of circulating strains. Microb Genom 2021; 7. [PMID: 34184981 PMCID: PMC8461462 DOI: 10.1099/mgen.0.000599] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lymphogranuloma venereum (LGV), the invasive infection of the sexually transmissible infection (STI) Chlamydia trachomatis, is caused by strains from the LGV biovar, most commonly represented by ompA-genotypes L2b and L2. We investigated the diversity in LGV samples across an international collection over seven years using typing and genome sequencing. LGV-positive samples (n=321) from eight countries collected between 2011 and 2017 (Spain n=97, Netherlands n=67, Switzerland n=64, Australia n=53, Sweden n=37, Hungary n=31, Czechia n=30, Slovenia n=10) were genotyped for pmpH and ompA variants. All were found to contain the 9 bp insertion in the pmpH gene, previously associated with ompA-genotype L2b. However, analysis of the ompA gene shows ompA-genotype L2b (n=83), ompA-genotype L2 (n=180) and several variants of these (n=52; 12 variant types), as well as other/mixed ompA-genotypes (n=6). To elucidate the genomic diversity, whole genome sequencing (WGS) was performed from selected samples using SureSelect target enrichment, resulting in 42 genomes, covering a diversity of ompA-genotypes and representing most of the countries sampled. A phylogeny of these data clearly shows that these ompA-genotypes derive from an ompA-genotype L2b ancestor, carrying up to eight SNPs per isolate. SNPs within ompA are overrepresented among genomic changes in these samples, each of which results in an amino acid change in the variable domains of OmpA (major outer membrane protein, MOMP). A reversion to ompA-genotype L2 with the L2b genomic backbone is commonly seen. The wide diversity of ompA-genotypes found in these recent LGV samples indicates that this gene is under immunological selection. Our results suggest that the ompA-genotype L2b genomic backbone is the dominant strain circulating and evolving particularly in men who have sex with men (MSM) populations.
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Affiliation(s)
- Helena M B Seth-Smith
- Clinical Bacteriology & Mycology, University Hospital Basel, University of Basel, Switzerland.,Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland.,SIB Swiss Institute of Bioinformatics, Basel, Switzerland
| | - Angèle Bénard
- Present address: Healthcare Systems Research Group, VHIR, Universitat Autònoma de Barcelona, Passeig de la Vall d'Hebron 119-129, 08035 Barcelona, Spain.,Wellcome Trust Sanger Institute, Cambridge, UK
| | - Sylvia M Bruisten
- Department of Infectious Diseases, GGD Public Health Service of Amsterdam, Amsterdam, The Netherlands.,Amsterdam UMC, University of Amsterdam, Amsterdam Institute for Infection and Immunity (AII), Location Academic Medical Centre, Amsterdam, The Netherlands
| | - Bart Versteeg
- Department of Infectious Diseases, GGD Public Health Service of Amsterdam, Amsterdam, The Netherlands.,Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Björn Herrmann
- Section of Clinical Bacteriology, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Jen Kok
- Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, Westmead Hospital, Westmead, New South Wales, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity & Westmead Clinical School, University of Sydney, Sydney, New South Wales, Australia
| | - Ian Carter
- Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, Westmead Hospital, Westmead, New South Wales, Australia
| | - Olivia Peuchant
- CHU Bordeaux, Department of Bacteriology, French National Reference Center for bacterial STIs, Bordeaux, France
| | - Cécile Bébéar
- CHU Bordeaux, Department of Bacteriology, French National Reference Center for bacterial STIs, Bordeaux, France
| | - David A Lewis
- Western Sydney Sexual Health Centre, Western Sydney Local Health District, Parramatta, New South Wales, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity & Westmead Clinical School, University of Sydney, Sydney, New South Wales, Australia
| | - Teresa Puerta
- Unidad de ITS/VIH, Centro Sanitario Sandoval, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria San Carlos (IdISSC), Madrid, Spain
| | - Darja Keše
- University of Ljubljana, Faculty of Medicine, Institute of Microbiology and Immunology, Ljubljana, Slovenia
| | - Eszter Balla
- Bacterial STI Reference Laboratory, National Public Health Center (former National Center for Epidemiology), Budapest, Hungary
| | - Hana Zákoucká
- National Reference Laboratory for Diagnostics of Syphilis and Chlamydia Infections, National Institute of Public Health, Srobarova 48, 100 42, Prague 10, Czech Republic
| | - Filip Rob
- Department of Dermatovenereology, Second Faculty of Medicine, Charles University and Hospital Bulovka, Budinova 2, 180 81, Prague 8, Czech Republic
| | - Servaas A Morré
- Laboratory of Immunogenetics, Department of Medical Microbiology and Infection Control, VU University Medical Center Amsterdam, Amsterdam, The Netherlands.,Institute for Public Health Genomics (IPHG), Department of Genetics and Cell Biology, Research Institute GROW, University of Maastricht, Maastricht, The Netherlands
| | - Bertille de Barbeyrac
- CHU Bordeaux, Department of Bacteriology, French National Reference Center for bacterial STIs, Bordeaux, France
| | - Juan Carlos Galán
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal. Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain. CIBER en Epidemiología y Salud Pública (CIBERESP)
| | - Henry J C de Vries
- Department of Infectious Diseases, GGD Public Health Service of Amsterdam, Amsterdam, The Netherlands.,Amsterdam UMC, University of Amsterdam, Amsterdam Institute for Infection and Immunity (AII), Location Academic Medical Centre, Amsterdam, The Netherlands
| | - Nicholas R Thomson
- Wellcome Trust Sanger Institute, Cambridge, UK.,Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Daniel Goldenberger
- Clinical Bacteriology & Mycology, University Hospital Basel, University of Basel, Switzerland
| | - Adrian Egli
- Clinical Bacteriology & Mycology, University Hospital Basel, University of Basel, Switzerland.,Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland
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Generation of a novel affibody molecule targeting Chlamydia trachomatis MOMP. Appl Microbiol Biotechnol 2021; 105:1477-1487. [PMID: 33521848 PMCID: PMC7880956 DOI: 10.1007/s00253-021-11128-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 01/07/2021] [Accepted: 01/19/2021] [Indexed: 11/30/2022]
Abstract
Abstract Chlamydia trachomatis (C. trachomatis) is the leading cause of preventable blindness worldwide and the most prevalent cause of bacterial sexually transmitted diseases. At present, there is no available vaccine, and recurrences after antibiotics treatment are substantial problems. Major outer membrane protein (MOMP) accounts for 60% of the outer mass of C. trachomatis, functioning as trimeric porin, and it is highly antigenic. Therefore, MOMP is the most promising candidate for vaccine developing and target therapy of Chlamydia. Affibody, a new class of affinity ligands derived from the Z-domain in the binding region of Staphylococcus aureus protein A, has been the focus of researchers as a viable alternative to antibodies. In this study, the MOMP-targeted affibody molecule (ZMOMP:461) was screened by phage-displayed peptide library. Further, the affinity and specificity were characterized by surface plasmon resonance (SPR) and Western blot. Immunofluorescence assay (IFA) indicated that the MOMP-binding affibody could recognize native MOMP in HeLa229 cells infected C. trachomatis. Immunoprecipitation assay confirmed further that ZMOMP:461 molecule specifically recognizes the epitope on relaxed trimer MOMP. Our findings provide strong evidence that affibody molecule (ZMOMP:461) serves as substitute for MOMP antibody for biological applications and has a great potential for delivering drugs for target therapy. Key points • We screened a novel affibody molecule ZMOMP:461 targeting Chlamydia trachomatis MOMP. • ZMOMP:461 recognizes the recombinant and native MOMP with high affinity and specificity. • ZMOMP:461 could be internalized into live target cells. Supplementary Information The online version contains supplementary material available at 10.1007/s00253-021-11128-x.
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Borges V, Cordeiro D, Salas AI, Lodhia Z, Correia C, Isidro J, Fernandes C, Rodrigues AM, Azevedo J, Alves J, Roxo J, Rocha M, Côrte-Real R, Vieira L, Borrego MJ, Gomes JP. Chlamydia trachomatis: when the virulence-associated genome backbone imports a prevalence-associated major antigen signature. Microb Genom 2020; 5. [PMID: 31697227 PMCID: PMC6927300 DOI: 10.1099/mgen.0.000313] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Chlamydia trachomatis is the most prevalent sexually transmitted bacterium worldwide and the causative agent of trachoma. Its strains are classified according to their ompA genotypes, which are strongly linked to differential tissue tropism and disease outcomes [ocular disease, urogenital disease and lymphogranuloma venereum (LGV)]. While the genome-based species phylogenetic tree presents four main clades correlating with tropism/prevalence, namely ocular, LGV, urogenital T1 (more prevalent genotypes) and urogenital T2 (less prevalent genotypes), inter-clade exchange of ompA is considered a rare phenomenon probably mediating marked tropism alterations. An LGV epidemic, associated with the clonal expansion of the L2b genotype, has emerged in the last few decades, raising concerns particularly due to its atypical clinical presentation (ulcerative proctitis) and circulation among men who have sex with men (MSM). Here, we report an LGV outbreak, mostly affecting human immunodeficiency virus-positive MSM engaging in high-risk sexual practices, caused by an L2b strain with a rather unique non-LGV ompA signature that precluded the laboratory notification of this outbreak as LGV. C. trachomatis whole-genome capture and sequencing directly from clinical samples was applied to deeply characterize the genomic backbone of this novel LGV outbreak-causing clone. It revealed a chimeric genome structure due to the genetic transfer of ompA and four neighbouring genes from a serovar D/Da strain, likely possessing the genomic backbone associated with the more prevalent urogenital genotypes (T1 clade), to an LGV (L2b) strain. The hybrid L2b/D-Da strain presents the adhesin and immunodominant antigen MOMP (major outer membrane protein) (encoded by ompA) with an epitope repertoire typical of non-invasive genital strains, while keeping the genome-dispersed virulence fingerprint of a classical LGV strain. As previously reported for inter-clade ompA exchange among non-LGV clades, this novel C. trachomatis genomic mosaic involving a contemporary epidemiologically and clinically relevant LGV strain may have implications on its transmission, tissue tropism and pathogenic capabilities. The emergence of variants with epidemic and pathogenic potential highlights the need for more focused surveillance strategies to capture C. trachomatis evolution in action.
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Affiliation(s)
- Vítor Borges
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
| | - Dora Cordeiro
- National Reference Laboratory (NRL) for Curable Sexually Transmitted Infections (STIs), National Institute of Health, Lisbon, Portugal
| | - Ana Isabel Salas
- National Reference Laboratory (NRL) for Curable Sexually Transmitted Infections (STIs), National Institute of Health, Lisbon, Portugal
| | - Zohra Lodhia
- National Reference Laboratory (NRL) for Curable Sexually Transmitted Infections (STIs), National Institute of Health, Lisbon, Portugal
| | - Cristina Correia
- National Reference Laboratory (NRL) for Curable Sexually Transmitted Infections (STIs), National Institute of Health, Lisbon, Portugal
| | - Joana Isidro
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
| | - Cândida Fernandes
- Sexually Transmitted Diseases Clinic, Dermatovenereology Department, Central Lisbon University Hospital Centre (CHULC), Lisbon, Portugal
| | - Ana Maria Rodrigues
- Sexually Transmitted Diseases Clinic, Dermatovenereology Department, Central Lisbon University Hospital Centre (CHULC), Lisbon, Portugal
| | - Jacinta Azevedo
- Sexually Transmitted Diseases Clinic, Lapa Health Centre, Lisbon, Portugal
| | - João Alves
- Sexually Transmitted Diseases Clinic, Lapa Health Centre, Lisbon, Portugal
| | - João Roxo
- CheckpointLX, Grupo de Ativistas em Tratamentos, Lisboa, Portugal
| | - Miguel Rocha
- CheckpointLX, Grupo de Ativistas em Tratamentos, Lisboa, Portugal
| | - Rita Côrte-Real
- Sexually Transmitted Diseases Clinic, Dermatovenereology Department, Central Lisbon University Hospital Centre (CHULC), Lisbon, Portugal
| | - Luís Vieira
- Innovation and Technology Unit, Department of Human Genetics, National Institute of Health, Lisbon, Portugal
| | - Maria José Borrego
- National Reference Laboratory (NRL) for Curable Sexually Transmitted Infections (STIs), National Institute of Health, Lisbon, Portugal
| | - João Paulo Gomes
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
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8
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Rawre J, Dhawan B, Khanna N, Sreenivas V, Broor S, Chaudhry R. Distribution of Chlamydia trachomatis omp A genotypes in patients attending a sexually transmitted disease outpatient clinic in New Delhi, India. Indian J Med Res 2020; 149:662-670. [PMID: 31417035 PMCID: PMC6702700 DOI: 10.4103/ijmr.ijmr_1171_17] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Background & objectives: Limited data are available on the typing of Chlamydia trachomatis in India. Serovars D to K of C. trachomatis are chiefly responsible for urogenital infections. Thus, this study was conducted to determine the distribution of C. trachomatis serovars in patients with urogenital infections and to characterize ompA gene of the detected C. trachomatis isolates by sequence analysis. Presence of other co-infections was also evaluated. Methods: Endocervical swabs were collected from 324 women and urethral swabs/urine were collected from 193 men attending the sexually transmitted diseases outpatient clinic. The samples were screened for C. trachomatis by cryptic plasmid PCR and ompA gene PCR. Genotyping was performed by PCR-restriction fragment length polymorphism (RFLP) and sequencing of the ompA gene. Samples were screened for genital mycoplasmas, Neisseria gonorrhoeae, Treponema pallidum and human immunodeficiency virus (HIV). Results: C. trachomatis was found in 15.0 per cent men and 10.8 per cent women. Serovar D was the most prevalent followed by serovars E, F, I and G. Twenty two C. trachomatis isolates were selected for ompA gene sequencing. No mixed infection was found. Variability in ompA sequences was seen in
31.8 per cent cases. Both PCR-RFLP and ompA gene sequencing showed concordant results. The presence of Ureaplasma spp. and Mycoplasma hominis was observed in 18.7 and 9.5 per cent patients, respectively. Co-infection of C. trachomatis was significantly associated with Ureaplasma urealyticum and HIV. Interpretation & conclusions: The high occurence of C. trachomatis infections warrants its screening in addition to other sexually transmitted infections namely U. urealyticum and HIV. Genotyping of the ompA gene may provide additional information for vaccine development.
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Affiliation(s)
- Jyoti Rawre
- Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India
| | - Benu Dhawan
- Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India
| | - Neena Khanna
- Department of Dermatology and Venereology, All India Institute of Medical Sciences, New Delhi, India
| | | | - Shobha Broor
- Department of Microbiology, SGT Medical College, Gurugram, India
| | - Rama Chaudhry
- Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India
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Abraham S, Juel HB, Bang P, Cheeseman HM, Dohn RB, Cole T, Kristiansen MP, Korsholm KS, Lewis D, Olsen AW, McFarlane LR, Day S, Knudsen S, Moen K, Ruhwald M, Kromann I, Andersen P, Shattock RJ, Follmann F. Safety and immunogenicity of the chlamydia vaccine candidate CTH522 adjuvanted with CAF01 liposomes or aluminium hydroxide: a first-in-human, randomised, double-blind, placebo-controlled, phase 1 trial. THE LANCET. INFECTIOUS DISEASES 2019; 19:1091-1100. [DOI: 10.1016/s1473-3099(19)30279-8] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 04/30/2019] [Accepted: 05/22/2019] [Indexed: 12/18/2022]
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10
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Patiño LH, Camargo M, Muñoz M, Ríos-Chaparro DI, Patarroyo MA, Ramírez JD. Unveiling the Multilocus Sequence Typing (MLST) Schemes and Core Genome Phylogenies for Genotyping Chlamydia trachomatis. Front Microbiol 2018; 9:1854. [PMID: 30186244 PMCID: PMC6113918 DOI: 10.3389/fmicb.2018.01854] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 07/24/2018] [Indexed: 11/21/2022] Open
Abstract
Multilocus sequence typing (MLST) has become a useful tool for studying the genetic diversity of important public health pathogens, such as Chlamydia trachomatis (Ct). Four MLST schemes have been proposed for Ct (data available from Chlamydiales MLST databases). However, the lack of a sole standardized scheme represents the greatest limitation regarding typing this species. This study was thus aimed at evaluating the usefulness of the four MLST schemes available for Ct, describing each molecular marker's pattern and its contribution toward a description of intra-specific genetic diversity and population structure. The markers for each scheme, showed a variable power of dicrimination, exhibiting in some cases over estimation in the determination of Sequence Types (STs). However, individual analysis of each locus's typing efficiency and discrimination power led to identifying 8 markers as having a suitable pattern for intra-specific typing. analyzing the 8 candidate markers gave a combination of 3 of these loci as an optimal scheme for identifying a large amount of STs, maximizing discrimination power whilst maintaining suitable typing efficiency. One scheme was compared against core genome phylogenies, finding a higher typing resolution through the last approach. These results confirm once again that although complete genome data, in particular from core genome MLST (cgMLST) allow a high resolution clustering for Ct isolates. There are combinations of molecular markers that could generate equivalent results, with the advantage of representing an easy implementation strategy and lower costs leading to contribute to the monitoring and molecular epidemiology of Ct.
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Affiliation(s)
- Luz H. Patiño
- Grupo de Investigaciones Microbiológicas-UR (GIMUR), Programa de Biología, Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Bogotá, Colombia
- Ph.D. Programme in Biomedical and Biological Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Milena Camargo
- Ph.D. Programme in Biomedical and Biological Sciences, Universidad del Rosario, Bogotá, Colombia
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
| | - Marina Muñoz
- Grupo de Investigaciones Microbiológicas-UR (GIMUR), Programa de Biología, Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Bogotá, Colombia
| | - Dora I. Ríos-Chaparro
- Grupo de Investigaciones Microbiológicas-UR (GIMUR), Programa de Biología, Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Bogotá, Colombia
| | - Manuel A. Patarroyo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
- School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Juan D. Ramírez
- Grupo de Investigaciones Microbiológicas-UR (GIMUR), Programa de Biología, Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Bogotá, Colombia
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Urogenital Chlamydia trachomatis multilocus sequence types and genovar distribution in chlamydia infected patients in a multi-ethnic region of Saratov, Russia. PLoS One 2018; 13:e0195386. [PMID: 29641543 PMCID: PMC5895025 DOI: 10.1371/journal.pone.0195386] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 03/21/2018] [Indexed: 11/19/2022] Open
Abstract
Background This is the first report to characterize the prevalence and genovar distribution of genital chlamydial infections among random heterosexual patients in the multi-ethnic Saratov Region, located in Southeast Russia. Methods Sixty-one clinical samples (cervical or urethral swabs) collected from a random cohort of 856 patients (7.1%) were C. trachomatis (CT) positive in commercial nucleic acid amplification tests (NAATs) and duplex TaqMan PCRs. Results Sequence analysis of the VDII region of the ompA gene revealed seven genovars of C. trachomatis in PCR-positive patients. The overall genovars were distributed as E (41.9%), G (21.6%), F (13.5%), K (9.5%), D (6.8%), J (4.1%), and H (2.7%). CT-positive samples were from males (n = 12, 19.7%), females (n = 42, 68.8%), and anonymous (n = 7, 11.5%) patients, with an age range of 19 to 45 years (average 26.4), including 12 different ethnic groups representative of this region. Most patients were infected with a single genovar (82%), while 18% were co-infected with either two or three genovars. The 1156 bp-fragment of the ompA gene was sequenced in 46 samples to determine single nucleotide polymorphisms (SNP) among isolates. SNP-based subtyping and phylogenetic reconstruction revealed the presence of 13 variants of the ompA gene, such as E (E1, E2, E6), G (G1, G2, G3, G5), F1, K, D (D1, Da2), J1, and H2. Differing genovar distribution was identified among urban (E>G>F) and rural (E>K) populations, and in Slavic (E>G>D) and non-Slavic (E>G>K) ethnic groups. Multilocus sequence typing (MLST) determined five sequences types (STs), such as ST4 (56%, 95% confidence interval, CI, 70.0 to 41.3), ST6 (10%, 95% CI 21.8 to 3.3), ST9 (22%, 95% CI 35.9 to 11.5), ST10 (2%, 95% CI 10.7 to 0.05) and ST38 (10%, 95% CI 21.8 to 3.3). Thus, the most common STs were ST4 and ST9. Conclusion C. trachomatis is a significant cause of morbidity among random heterosexual patients with genital chlamydial infections in the Saratov Region. Further studies should extend this investigation by describing trends in a larger population, both inside and outside of the Saratov Region to clarify some aspects for the actual application of C. trachomatis genotype analysis for disease control.
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12
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Turingan RS, Kaplun L, Krautz-Peterson G, Norsworthy S, Zolotova A, Joseph SJ, Read TD, Dean D, Tan E, Selden RF. Rapid detection and strain typing of Chlamydia trachomatis using a highly multiplexed microfluidic PCR assay. PLoS One 2017; 12:e0178653. [PMID: 28562672 PMCID: PMC5451082 DOI: 10.1371/journal.pone.0178653] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 05/16/2017] [Indexed: 11/19/2022] Open
Abstract
Nucleic acid amplification tests (NAATs) are recommended by the CDC for detection of Chlamydia trachomatis (Ct) urogenital infections. Current commercial NAATs require technical expertise and sophisticated laboratory infrastructure, are time-consuming and expensive, and do not differentiate the lymphogranuloma venereum (LGV) strains that require a longer duration of treatment than non-LGV strains. The multiplexed microfluidic PCR-based assay presented in this work simultaneously interrogates 13 loci to detect Ct and identify LGV and non-LGV strain-types. Based on amplified fragment length polymorphisms, the assay differentiates LGV, ocular, urogenital, and proctocolitis clades, and also serovars L1, L2, and L3 within the LGV group. The assay was evaluated in a blinded fashion using 95 clinical swabs, with 76 previously reported as urogenital Ct-positive samples and typed by ompA genotyping and/or Multi-Locus Sequence Typing. Results of the 13-plex assay showed that 51 samples fell within urogenital clade 2 or 4, 24 samples showed both clade 2 and 4 signatures, indicating possible mixed infection, gene rearrangement, or inter-clade recombination, and one sample was a noninvasive trachoma biovar (either a clade 3 or 4). The remaining 19 blinded samples were correctly identified as LGV clade 1 (3), ocular clade 3 (4), or as negatives (12). To date, no NAAT assay can provide a point-of-care applicable turnaround time for Ct detection while identifying clinically significant Ct strain types to inform appropriate treatment. Coupled with rapid DNA processing of clinical swabs (approximately 60 minutes from swab-in to result-out), the assay has significant potential as a rapid POC diagnostic for Ct infections.
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Affiliation(s)
| | - Ludmila Kaplun
- NetBio, Waltham, Massachusetts, United States of America
| | | | | | - Anna Zolotova
- NetBio, Waltham, Massachusetts, United States of America
| | - Sandeep J. Joseph
- Department of Medicine, Division of Infectious Diseases and Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Timothy D. Read
- Department of Medicine, Division of Infectious Diseases and Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Deborah Dean
- Center for Immunobiology and Vaccine Development, Children’s Hospital Oakland Research Institute, Oakland, California, United States of America
- University of California at San Francisco School of Medicine, San Francisco, California, United States of America
- University of California at Berkeley and University of California at San Francisco Joint Graduate Program in Bioengineering, Berkeley, California, United States of America
| | - Eugene Tan
- NetBio, Waltham, Massachusetts, United States of America
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13
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Chahota R, Ogawa H, Ohya K, Yamaguchi T, Everett KDE, Fukushi H. Involvement of multiple Chlamydia suis genotypes in porcine conjunctivitis. Transbound Emerg Dis 2017; 65:272-277. [PMID: 28345224 DOI: 10.1111/tbed.12645] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Indexed: 01/07/2023]
Abstract
Chlamydia suis has been detected in numerous disease conditions of pigs, particularly in eye infections. This study examined recurring conjunctivitis cases in five commercial pig farms in Japan. 40.5% of the cases were identified as Chlamydia positive using impression cytology of ocular smears and a genus-specific direct fluorescent antibody. C. suis was detected in 59.5% of the samples using PCR tests targeting 16S-23S rRNA intergenic spacer region (ISR) and ompA gene. Genetic analysis of PCR amplicons revealed nine sequence variants of 16S-23S rRNA ISR and 20 sequence variants within ompA gene. Among C. suis-positive conjunctivitis cases, 36.4% showed concurrent infection with 2-4 varied ompA sequence types and 9.1% showed multiple 16S-23S rRNA ISR sequence types of C. suis. Multiple genotypes were found circulating in four of five farms. All 20 detected strains and 25 previously reported C. suis strains were grouped into four clusters. Japanese C. suis strains were closely related to American and European strains indicating wide distribution of these genetically variant strains. This study is the first to show multiple and genetically diverse C. suis strain associations in pig conjunctivitis.
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Affiliation(s)
- R Chahota
- Department of Applied Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan.,Department of Veterinary Microbiology, DGCN College of Veterinary and Animal Sciences, CSK HPKV, Palampur, India
| | - H Ogawa
- Department of Applied Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - K Ohya
- Laboratory of Veterinary Microbiology, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - T Yamaguchi
- The Avian Zoonosis Research Center, Faculty of Agriculture, Tottori University, Tottori, Japan
| | | | - H Fukushi
- Department of Applied Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan.,Laboratory of Veterinary Microbiology, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
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Rawre J, Dhawan B, Malhotra N, Sreenivas V, Broor S, Chaudhry R. Prevalence and distribution of Chlamydia trachomatis genovars in Indian infertile patients: a pilot study. APMIS 2017; 124:1109-1115. [PMID: 27859690 DOI: 10.1111/apm.12622] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 08/25/2016] [Indexed: 10/20/2022]
Abstract
To determine the prevalence and distribution of Chlamydia trachomatis genovars in patients with infertility by PCR-RFLP and ompA gene sequencing. Prevalence of other etiological agents (viz., Ureaplasma spp. and Mycoplasma hominis) were also assessed. Endocervical swabs were collected from 477 women and urine was collected from 151 men attending the Infertility Clinic. The samples were screened for C. trachomatis by cryptic plasmid, ompA gene and nested ompA gene PCR. Genotyping was performed by PCR-RFLP and sequencing. Samples were screened for Ureaplasma spp. and M. hominis. The prevalence of C. trachomatis in infertile women and their male partners were 15.7% (75 of 477) and 10.0% (15 of 151) respectively. Secondary infertility was significantly associated with chlamydial infection. Genovar E was the most prevalent followed by genovar D and F. Twenty-four C. trachomatis strains were selected for ompA gene sequencing. No mixed infection was picked. Variability in ompA sequences was seen in 50.0%. Both PCR-RFLP and ompA gene sequencing showed concordant results. High prevalence of C. trachomatis in infertile couples warrants routine screening for C. trachomatis infection in all infertile couples. Genotyping of the ompA gene of C. trachomatis may be a valuable tool in understanding the natural history of C. trachomatis infection.
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Affiliation(s)
- Jyoti Rawre
- Department of Microbiology, AIIMS, New Delhi, India
| | - Benu Dhawan
- Department of Microbiology, AIIMS, New Delhi, India
| | - Neena Malhotra
- Department of Gynecology and Obstetrics, AIIMS, New Delhi, India
| | | | - Shobha Broor
- Department of Microbiology, SGT Medical College, Gurgaon, India
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Abstract
Etiology, transmission and protection: Chlamydia
trachomatis is the leading cause of bacterial sexually transmitted
infection (STI) globally. However, C. trachomatis also causes
trachoma in endemic areas, mostly Africa and the Middle East, and is a leading
cause of preventable blindness worldwide. Epidemiology, incidence and
prevalence: The World Health Organization estimates 131 million
new cases of C. trachomatis genital infection occur annually.
Globally, infection is most prevalent in young women and men (14-25 years),
likely driven by asymptomatic infection, inadequate partner treatment and
delayed development of protective immunity.
Pathology/Symptomatology: C.
trachomatis infects susceptible squamocolumnar or transitional
epithelial cells, leading to cervicitis in women and urethritis in men. Symptoms
are often mild or absent but ascending infection in some women may lead to
Pelvic Inflammatory Disease (PID), resulting in reproductive sequelae such as
ectopic pregnancy, infertility and chronic pelvic pain. Complications of
infection in men include epididymitis and reactive arthritis.
Molecular mechanisms of infection: Chlamydiae
manipulate an array of host processes to support their obligate intracellular
developmental cycle. This leads to activation of signaling pathways resulting in
disproportionate influx of innate cells and the release of tissue damaging
proteins and pro-inflammatory cytokines. Treatment and
curability: Uncomplicated urogenital infection is treated with
azithromycin (1 g, single dose) or doxycycline (100 mg twice daily x 7 days).
However, antimicrobial treatment does not ameliorate established disease. Drug
resistance is rare but treatment failures have been described. Development of an
effective vaccine that protects against upper tract disease or that limits
transmission remains an important goal.
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Affiliation(s)
- Catherine M O'Connell
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Morgan E Ferone
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Gharsallah H, Bom RJM, Bruisten SM, Himschoot M, Frikha-Gargouri O, Hammami A. Identification of a dominant Chlamydia trachomatis strain in patients attending sexual transmitted infection clinic and female sex workers in Tunisia using a high resolution typing method. INFECTION GENETICS AND EVOLUTION 2016; 44:444-449. [PMID: 27497657 DOI: 10.1016/j.meegid.2016.08.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 07/11/2016] [Accepted: 08/03/2016] [Indexed: 11/15/2022]
Abstract
BACKGROUND The distribution of Chlamydia trachomatis genotypes in Tunisia was previously studied using the reverse hybridization method. In this study, we used multilocus sequence typing (MLST) to describe Chlamydia trachomatis genetic diversity among heterosexual populations in Tunisia. The obtained sequence types (STs) were compared with those from a heterosexual population from Amsterdam, the Netherlands. METHODS Clinical Tunisian patients and female sex workers provided 107 Chlamydia trachomatis positive samples that were used for MLST. Samples from 256 heterosexuals visiting the Amsterdam STI clinic were included as a reference group. Six highly variable genetic regions including the ompA gene were amplified and sequenced. The ST numbers were derived from a Chlamydia typing database (http://mlstdb.uu.se) and used to draw minimum spanning trees. RESULTS ompA sequencing detected 7 genotypes among the Tunisian populations of which genotype E was the most prevalent (66.3%). This genotype E resolved into 23 different STs and among these the ST3 was predominant (53.5%). MLST displayed 43 STs, of which 28 (65%) were new in the database. Minimum spanning tree analysis of all Tunisian samples identified 4 clusters of which one formed a clonal cluster with samples presenting the most prevalent ST3. When comparing samples from the Tunisian and Dutch populations in one minimum spanning tree, there was little overlap between the Chlamydia trachomatis samples. CONCLUSION The CT-hrMLST scheme allowed us to identify that the Tunisian distribution was dominated by one genotype E (ST3) strain which is also highly prevalent in many other countries worldwide.
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Affiliation(s)
- Houda Gharsallah
- Department of Microbiology and research laboratory "Microorganismes et Pathologies Humaines", Habib Bourguiba University Hospital, Medical School of Sfax, Avenue Majida Boulila 3000, University of Sfax, Tunisia.
| | - Reinier J M Bom
- Public Health Laboratory, Public Health Service of Amsterdam (GGD Amsterdam), Nieuwe Achtergracht 100, 1018 WT Amsterdam, The Netherlands.
| | - Sylvia M Bruisten
- Public Health Laboratory, Public Health Service of Amsterdam (GGD Amsterdam), Nieuwe Achtergracht 100, 1018 WT Amsterdam, The Netherlands.
| | - Michelle Himschoot
- Public Health Laboratory, Public Health Service of Amsterdam (GGD Amsterdam), Nieuwe Achtergracht 100, 1018 WT Amsterdam, The Netherlands.
| | - Olfa Frikha-Gargouri
- Department of Microbiology and research laboratory "Microorganismes et Pathologies Humaines", Habib Bourguiba University Hospital, Medical School of Sfax, Avenue Majida Boulila 3000, University of Sfax, Tunisia; Biopesticides Team, Centre of Biotechnology of Sfax, Road of Sidi Mansour Km 6, 3018 Sfax, Tunisia.
| | - Adnene Hammami
- Department of Microbiology and research laboratory "Microorganismes et Pathologies Humaines", Habib Bourguiba University Hospital, Medical School of Sfax, Avenue Majida Boulila 3000, University of Sfax, Tunisia.
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Genital Chlamydia trachomatis: understanding the roles of innate and adaptive immunity in vaccine research. Clin Microbiol Rev 2016; 27:346-70. [PMID: 24696438 DOI: 10.1128/cmr.00105-13] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Chlamydia trachomatis is the leading cause of bacterial sexually transmitted disease worldwide, and despite significant advances in chlamydial research, a prophylactic vaccine has yet to be developed. This Gram-negative obligate intracellular bacterium, which often causes asymptomatic infection, may cause pelvic inflammatory disease (PID), ectopic pregnancies, scarring of the fallopian tubes, miscarriage, and infertility when left untreated. In the genital tract, Chlamydia trachomatis infects primarily epithelial cells and requires Th1 immunity for optimal clearance. This review first focuses on the immune cells important in a chlamydial infection. Second, we summarize the research and challenges associated with developing a chlamydial vaccine that elicits a protective Th1-mediated immune response without inducing adverse immunopathologies.
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Badamchi-Zadeh A, McKay PF, Korber BT, Barinaga G, Walters AA, Nunes A, Gomes JP, Follmann F, Tregoning JS, Shattock RJ. A Multi-Component Prime-Boost Vaccination Regimen with a Consensus MOMP Antigen Enhances Chlamydia trachomatis Clearance. Front Immunol 2016; 7:162. [PMID: 27199987 PMCID: PMC4848310 DOI: 10.3389/fimmu.2016.00162] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 04/15/2016] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND A vaccine for Chlamydia trachomatis is of urgent medical need. We explored bioinformatic approaches to generate an immunogen against C. trachomatis that would induce cross-serovar T-cell responses as (i) CD4(+) T cells have been shown in animal models and human studies to be important in chlamydial protection and (ii) antibody responses may be restrictive and serovar specific. METHODS A consensus antigen based on over 1,500 major outer membrane protein (MOMP) sequences provided high epitope coverage against the most prevalent C. trachomatis strains in silico. Having designed the T-cell immunogen, we assessed it for immunogenicity in prime-boost regimens. This consensus MOMP transgene was delivered using plasmid DNA, Human Adenovirus 5 (HuAd5) or modified vaccinia Ankara (MVA) vectors with or without MF59(®) adjuvanted recombinant MOMP protein. RESULTS Different regimens induced distinct immune profiles. The DNA-HuAd5-MVA-Protein vaccine regimen induced a cellular response with a Th1-biased serum antibody response, alongside high serum and vaginal MOMP-specific antibodies. This regimen significantly enhanced clearance against intravaginal C. trachomatis serovar D infection in both BALB/c and B6C3F1 mouse strains. This enhanced clearance was shown to be CD4(+) T-cell dependent. Future studies will need to confirm the specificity and precise mechanisms of protection. CONCLUSION A C. trachomatis vaccine needs to induce a robust cellular response with broad cross-serovar coverage and a heterologous prime-boost regimen may be an approach to achieve this.
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Affiliation(s)
| | - Paul F McKay
- Mucosal Infection and Immunity Group, Imperial College London , London , UK
| | - Bette T Korber
- Los Alamos National Laboratory, Theoretical Division , Los Alamos, NM , USA
| | - Guillermo Barinaga
- Mucosal Infection and Immunity Group, Imperial College London , London , UK
| | - Adam A Walters
- Mucosal Infection and Immunity Group, Imperial College London , London , UK
| | - Alexandra Nunes
- Department of Infectious Diseases, National Institute of Health , Lisbon , Portugal
| | - João Paulo Gomes
- Department of Infectious Diseases, National Institute of Health , Lisbon , Portugal
| | - Frank Follmann
- Chlamydia Vaccine Research, Department of Infectious Disease Immunology, Statens Serum Institute , Copenhagen , Denmark
| | - John S Tregoning
- Mucosal Infection and Immunity Group, Imperial College London , London , UK
| | - Robin J Shattock
- Mucosal Infection and Immunity Group, Imperial College London , London , UK
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Zurli V, Gallotta M, Taccone M, Chiarot E, Brazzoli M, Corrente F, Bonci A, Casini D, De Gregorio E, Baudner BC, Bertholet S, Seubert A. Positive Contribution of Adjuvanted Influenza Vaccines to the Resolution of Bacterial Superinfections. J Infect Dis 2016; 213:1876-85. [PMID: 26908732 DOI: 10.1093/infdis/jiw048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 01/27/2016] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Most preclinical studies assess vaccine effectiveness in single-pathogen infection models. This is unrealistic given that humans are continuously exposed to different commensals and pathogens in sequential and mixed infections. Accordingly, complications from secondary bacterial infection are a leading cause of influenza-associated morbidity and mortality. New vaccination strategies are needed to control infections on simultaneous fronts. METHODS We compared different anti-influenza vaccines for their protective potential in a model of viral infection with bacterial superinfection. Mice were immunized with H1N1/A/California/7/2009 subunit vaccines, formulated with different adjuvants inducing either T-helper type 1 (Th1) (MF59 plus CpG)-, Th1/2 (MF59)-, or Th17 (LTK63)-prone immune responses and were sequentially challenged with mouse-adapted influenza virus H1N1/A/Puerto Rico/8/1934 and Staphylococcus aureus USA300, a clonotype emerging as a leading contributor in postinfluenza pneumonia in humans. RESULTS Unadjuvanted vaccine controlled single viral infection, yet mice had considerable morbidity from viral disease and bacterial superinfection. In contrast, all adjuvanted vaccines efficiently protected mice in both conditions. Interestingly, the Th1-inducing formulation was superior to Th1/2 or Th17 inducers. CONCLUSIONS Our studies should help us better understand how differential immunity to influenza skews immune responses toward coinfecting bacteria and discover novel modes to prevent bacterial superinfections in the lungs of persons with influenza.
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Affiliation(s)
- Vanessa Zurli
- GSK Vaccines S.r.l., Vaccines Research Center, Siena Department of Biology, University of Padua, Italy
| | - Marilena Gallotta
- GSK Vaccines S.r.l., Vaccines Research Center, Siena Dynavax Technologies, Berkeley, California
| | | | | | | | | | | | | | | | | | | | - Anja Seubert
- GSK Vaccines S.r.l., Vaccines Research Center, Siena
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Dhawan B, Rawre J, Saigal K, Khanna N. Chlamydia trachomatis serovar G infection in a bisexual male with urethritis. Indian J Dermatol Venereol Leprol 2016; 82:523-6. [DOI: 10.4103/0378-6323.181470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Roulis E, Bachmann N, Humphrys M, Myers G, Huston W, Polkinghorne A, Timms P. Phylogenetic analysis of human Chlamydia pneumoniae strains reveals a distinct Australian indigenous clade that predates European exploration of the continent. BMC Genomics 2015; 16:1094. [PMID: 26694618 PMCID: PMC4687280 DOI: 10.1186/s12864-015-2281-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 12/08/2015] [Indexed: 12/05/2022] Open
Abstract
Background The obligate intracellular bacterium Chlamydia pneumoniae is a common respiratory pathogen, which has been found in a range of hosts including humans, marsupials and amphibians. Whole genome comparisons of human C. pneumoniae have previously highlighted a highly conserved nucleotide sequence, with minor but key polymorphisms and additional coding capacity when human and animal strains are compared. Results In this study, we sequenced three Australian human C. pneumoniae strains, two of which were isolated from patients in remote indigenous communities, and compared them to all available C. pneumoniae genomes. Our study demonstrated a phylogenetically distinct human C. pneumoniae clade containing the two indigenous Australian strains, with estimates that the most recent common ancestor of these strains predates the arrival of European settlers to Australia. We describe several polymorphisms characteristic to these strains, some of which are similar in sequence to animal C. pneumoniae strains, as well as evidence to suggest that several recombination events have shaped these distinct strains. Conclusions Our study reveals a greater sequence diversity amongst both human and animal C. pneumoniae strains, and suggests that a wider range of strains may be circulating in the human population than current sampling indicates.
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Affiliation(s)
- Eileen Roulis
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, QLD, Australia.
| | - Nathan Bachmann
- Centre for Animal Health Innovation, Faculty of Science, Health, Education & Engineering, University of the Sunshine Coast, Sippy Downs, QLD, Australia.
| | - Michael Humphrys
- Institute for Genomic Sciences, University of Maryland, Baltimore, MD, USA.
| | - Garry Myers
- i3 Institute, University of Technology, Sydney, NSW, Australia.
| | - Wilhelmina Huston
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, QLD, Australia. .,i3 Institute, University of Technology, Sydney, NSW, Australia.
| | - Adam Polkinghorne
- Centre for Animal Health Innovation, Faculty of Science, Health, Education & Engineering, University of the Sunshine Coast, Sippy Downs, QLD, Australia.
| | - Peter Timms
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, QLD, Australia. .,Centre for Animal Health Innovation, Faculty of Science, Health, Education & Engineering, University of the Sunshine Coast, Sippy Downs, QLD, Australia.
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Nunes A, Gomes JP, Karunakaran KP, Brunham RC. Bioinformatic Analysis of Chlamydia trachomatis Polymorphic Membrane Proteins PmpE, PmpF, PmpG and PmpH as Potential Vaccine Antigens. PLoS One 2015; 10:e0131695. [PMID: 26131720 PMCID: PMC4488443 DOI: 10.1371/journal.pone.0131695] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 06/05/2015] [Indexed: 12/31/2022] Open
Abstract
Chlamydia trachomatis is the most important infectious cause of infertility in women with important implications in public health and for which a vaccine is urgently needed. Recent immunoproteomic vaccine studies found that four polymorphic membrane proteins (PmpE, PmpF, PmpG and PmpH) are immunodominant, recognized by various MHC class II haplotypes and protective in mouse models. In the present study, we aimed to evaluate genetic and protein features of Pmps (focusing on the N-terminal 600 amino acids where MHC class II epitopes were mapped) in order to understand antigen variation that may emerge following vaccine induced immune selection. We used several bioinformatics platforms to study: i) Pmps' phylogeny and genetic polymorphism; ii) the location and distribution of protein features (GGA(I, L)/FxxN motifs and cysteine residues) that may impact pathogen-host interactions and protein conformation; and iii) the existence of phase variation mechanisms that may impact Pmps' expression. We used a well-characterized collection of 53 fully-sequenced strains that represent the C. trachomatis serovars associated with the three disease groups: ocular (N=8), epithelial-genital (N=25) and lymphogranuloma venereum (LGV) (N=20). We observed that PmpF and PmpE are highly polymorphic between LGV and epithelial-genital strains, and also within populations of the latter. We also found heterogeneous representation among strains for GGA(I, L)/FxxN motifs and cysteine residues, suggesting possible alterations in adhesion properties, tissue specificity and immunogenicity. PmpG and, to a lesser extent, PmpH revealed low polymorphism and high conservation of protein features among the genital strains (including the LGV group). Uniquely among the four Pmps, pmpG has regulatory sequences suggestive of phase variation. In aggregate, the results suggest that PmpG may be the lead vaccine candidate because of sequence conservation but may need to be paired with another protective antigen (like PmpH) in order to prevent immune selection of phase variants.
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Affiliation(s)
- Alexandra Nunes
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
| | - João P. Gomes
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
| | - Karuna P. Karunakaran
- Vaccine Research Laboratory, University of British Columbia Centre for Disease Control, Vancouver, Canada
| | - Robert C. Brunham
- Vaccine Research Laboratory, University of British Columbia Centre for Disease Control, Vancouver, Canada
- * E-mail:
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Borges V, Gomes JP. Deep comparative genomics among Chlamydia trachomatis lymphogranuloma venereum isolates highlights genes potentially involved in pathoadaptation. INFECTION GENETICS AND EVOLUTION 2015; 32:74-88. [PMID: 25745888 DOI: 10.1016/j.meegid.2015.02.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/23/2015] [Accepted: 02/26/2015] [Indexed: 11/19/2022]
Abstract
Lymphogranuloma venereum (LGV) is a human sexually transmitted disease caused by the obligate intracellular bacterium Chlamydia trachomatis (serovars L1-L3). LGV clinical manifestations range from severe ulcerative proctitis (anorectal syndrome), primarily caused by the epidemic L2b strains, to painful inguinal lymphadenopathy (the typical LGV bubonic form). Besides potential host-related factors, the differential disease severity and tissue tropism among LGV strains is likely a function of the genetic backbone of the strains. We aimed to characterize the genetic variability among LGV strains as strain- or serovar-specific mutations may underlie phenotypic signatures, and to investigate the mutational events that occurred throughout the pathoadaptation of the epidemic L2b lineage. By analyzing 20 previously published genomes from L1, L2, L2b and L3 strains and two new genomes from L2b strains, we detected 1497 variant sites and about 100 indels, affecting 453 genes and 144 intergenic regions, with 34 genes displaying a clear overrepresentation of nonsynonymous mutations. Effectors and/or type III secretion substrates (almost all of those described in the literature) and inclusion membrane proteins showed amino acid changes that were about fivefold more frequent than silent changes. More than 120 variant sites occurred in plasmid-regulated virulence genes, and 66% yielded amino acid changes. The identified serovar-specific variant sites revealed that the L2b-specific mutations are likely associated with higher fitness and pointed out potential targets for future highly discriminatory diagnostic/typing tests. By evaluating the evolutionary pathway beyond the L2b clonal radiation, we observed that 90.2% of the intra-L2b variant sites occurring in coding regions involve nonsynonymous mutations, where CT456/tarp has been the main target. Considering the progress on C. trachomatis genetic manipulation, this study may constitute an important contribution for prioritizing study targets for functional genomics aiming to dissect the impact of the identified intra-LGV polymorphisms on virulence or tropism dissimilarities among LGV strains.
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Affiliation(s)
- Vítor Borges
- Reference Laboratory of Bacterial Sexually Transmitted Infections, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal; Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal
| | - João Paulo Gomes
- Reference Laboratory of Bacterial Sexually Transmitted Infections, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal; Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal.
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In silico scrutiny of genes revealing phylogenetic congruence with clinical prevalence or tropism properties of Chlamydia trachomatis strains. G3-GENES GENOMES GENETICS 2014; 5:9-19. [PMID: 25378473 PMCID: PMC4291473 DOI: 10.1534/g3.114.015354] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Microbes possess a multiplicity of virulence factors that confer them the ability to specifically infect distinct biological niches. Contrary to what is known for other bacteria, for the obligate intracellular human pathogen Chlamydia trachomatis, the knowledge of the molecular basis underlying serovars’ tissue specificity is scarce. We examined all ~900 genes to evaluate the association between individual phylogenies and cell-appetence or ecological success of C. trachomatis strains. Only ~1% of the genes presented a tree topology showing the segregation of all three disease groups (ocular, urogenital, and lymphatic) into three well-supported clades. Approximately 28% of the genes, which include the majority of the genes encoding putative type III secretion system effectors and Inc proteins, present a phylogenetic tree where only lymphogranuloma venereum strains form a clade. Similarly, an exclusive phylogenetic segregation of the most prevalent genital serovars was observed for 61 proteins. Curiously, these serovars are phylogenetically cosegregated with the lymphogranuloma venereum serovars for ~20% of the genes. Some clade-specific pseudogenes were identified (novel findings include the conserved hypothetical protein CT037 and the predicted α-hemolysin CT473), suggesting their putative expendability for the infection of particular niches. Approximately 3.5% of the genes revealed a significant overrepresentation of nonsynonymous mutations, and the majority encode proteins that directly interact with the host. Overall, this in silico scrutiny of genes whose phylogeny is congruent with clinical prevalence or tissue specificity of C. trachomatis strains may constitute an important database of putative targets for future functional studies to evaluate their biological role in chlamydial infections.
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Nunes A, Gomes JP. Evolution, phylogeny, and molecular epidemiology of Chlamydia. INFECTION GENETICS AND EVOLUTION 2014; 23:49-64. [PMID: 24509351 DOI: 10.1016/j.meegid.2014.01.029] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 01/16/2014] [Accepted: 01/19/2014] [Indexed: 10/25/2022]
Abstract
The Chlamydiaceae are a family of obligate intracellular bacteria characterized by a unique biphasic developmental cycle. It encompasses the single genus Chlamydia, which involves nine species that affect a wide range of vertebral hosts, causing infections with serious impact on human health (mainly due to Chlamydia trachomatis infections) and on farming and veterinary industries. It is believed that Chlamydiales originated ∼700mya, whereas C. trachomatis likely split from the other Chlamydiaceae during the last 6mya. This corresponds to the emergence of modern human lineages, with the first descriptions of chlamydial infections as ancient as four millennia. Chlamydiaceae have undergone a massive genome reduction, on behalf of the deletional bias "use it or lose it", stabilizing at 1-1.2Mb and keeping a striking genome synteny. Their phylogeny reveals species segregation according to biological properties, with huge differences in terms of host range, tissue tropism, and disease outcomes. Genome differences rely on the occurrence of mutations in the >700 orthologous genes, as well as on events of recombination, gene loss, inversion, and paralogous expansion, affecting both a hypervariable region named the plasticity zone, and genes essentially encoding polymorphic and transmembrane head membrane proteins, type III secretion effectors and some metabolic pathways. Procedures for molecular typing are still not consensual but have allowed the knowledge of molecular epidemiology patterns for some species as well as the identification of outbreaks and emergence of successful clones for C. trachomatis. This manuscript intends to provide a comprehensive review on the evolution, phylogeny, and molecular epidemiology of Chlamydia.
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Affiliation(s)
- Alexandra Nunes
- Reference Laboratory of Bacterial Sexually Transmitted Infections and Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal
| | - João P Gomes
- Reference Laboratory of Bacterial Sexually Transmitted Infections and Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal.
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Rosenzweig JA, Chopra AK. Modulation of host immune defenses by Aeromonas and Yersinia species: convergence on toxins secreted by various secretion systems. Front Cell Infect Microbiol 2013; 3:70. [PMID: 24199174 PMCID: PMC3812659 DOI: 10.3389/fcimb.2013.00070] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 10/14/2013] [Indexed: 12/20/2022] Open
Abstract
Like other pathogenic bacteria, Yersinia and Aeromonas species have been continuously co-evolving with their respective hosts. Although the former is a bonafide human pathogen, the latter has gained notararity as an emerging disease-causing agent. In response to immune cell challenges, bacterial pathogens have developed diverse mechanism(s) enabling their survival, and, at times, dominance over various host immune defense systems. The bacterial type three secretion system (T3SS) is evolutionarily derived from flagellar subunits and serves as a vehicle by which microbes can directly inject/translocate anti-host factors/effector proteins into targeted host immune cells. A large number of Gram-negative bacterial pathogens possess a T3SS empowering them to disrupt host cell signaling, actin cytoskeleton re-arrangements, and even to induce host-cell apoptotic and pyroptotic pathways. All pathogenic yersiniae and most Aeromonas species possess a T3SS, but they also possess T2- and T6-secreted toxins/effector proteins. This review will focus on the mechanisms by which the T3SS effectors Yersinia outer membrane protein J (YopJ) and an Aeromonas hydrophila AexU protein, isolated from the diarrheal isolate SSU, mollify host immune system defenses. Additionally, the mechanisms that are associated with host cell apoptosis/pyroptosis by Aeromonas T2SS secreted Act, a cytotoxic enterotoxin, and Hemolysin co-regulated protein (Hcp), an A. hydrophila T6SS effector, will also be discussed.
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Affiliation(s)
- Jason A Rosenzweig
- Department of Biology, Center for Bionanotechnology and Environmental Research, Texas Southern University Houston, TX, USA ; Department of Environmental and Interdisciplinary Sciences, Texas Southern University Houston, TX, USA
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Abdelsamed H, Peters J, Byrne GI. Genetic variation in Chlamydia trachomatis and their hosts: impact on disease severity and tissue tropism. Future Microbiol 2013; 8:1129-1146. [PMID: 24020741 PMCID: PMC4009991 DOI: 10.2217/fmb.13.80] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Chlamydia trachomatis infections are a global health problem. This obligate intracellular bacterial pathogen comprises lymphogranuloma venereum (L1-L3), ocular (A-C) and genital (D-K) serovars. Although genetically similar, each serovar group differs in disease severity and tissue tropism through mechanisms that are not well understood. It is clear that host genetic differences also play a role in chlamydial disease outcome and key host polymorphisms are beginning to emerge from both human and experimental animal studies. In this review, we will highlight pathogen and host genes that link genetic diversity, disease severity and tissue tropism. We will also use this information to provide new insights that may be helpful in developing improved management strategies for these important pathogens.
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Affiliation(s)
- Hossam Abdelsamed
- Department of Microbiology, Immunology & Biochemistry, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Jan Peters
- Department of Microbiology, Immunology & Biochemistry, University of Tennessee Health Sciences Center, Memphis, TN, USA
- Regional Biocontainment Laboratory, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Gerald I Byrne
- Department of Microbiology, Immunology & Biochemistry, University of Tennessee Health Sciences Center, Memphis, TN, USA
- Regional Biocontainment Laboratory, University of Tennessee Health Sciences Center, Memphis, TN, USA
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Wu JS, Zhao N, Pan H, Wang CM, Wu B, Zhang HM, He HX, Liu D, Amer S, Liu SL. Patterns of polymorphism and divergence in the VP1 gene of enterovirus 71 circulating in the Asia-Pacific region between 1994 and 2013. J Virol Methods 2013; 193:713-28. [PMID: 23933074 DOI: 10.1016/j.jviromet.2013.07.051] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 07/18/2013] [Accepted: 07/22/2013] [Indexed: 12/28/2022]
Abstract
Enterovirus 71 has been implicated in several outbreaks of hand, foot and mouth disease in the Asia-Pacific region. The present study aimed to achieve comprehensive evolutionary dynamic aspects of EV71 during 1994-2013, based on phylogenetic analyses of the VP1 sequences. The results indicated that 4 genotypes, namely C4, C1, C2 and B4 are the predominant strains, especially in Southeast Asian countries. No common ancestor was shared in different countries. Fourteen sites of substitutions were detected in the VP1 gene sequences; including the most common sites related to neutralization at position V249I [47.1% (189/401)] and A289T [42.6% (171/401)]. However, the sites Q22H and Q22R associated with increased virulence were recognized only in 13.7% (55/401) and 18% (72/401), respectively. None of the above mutations seemed to become fixed because the ratio of Ka/Ks was greater than 1.0. Mutations K43E, A58T, S184T, and T240S could possibly change the spatial structure. Two mutations, G145E and T240S, could obviously affect the hydrophobicity of VP1 and thus alter the EV71 immunoreactivity. In conclusion, the VP1 gene of EV71 strains circulating in the Asia-Pacific region during 1994-2013, showed polymorphisms and divergence with very slow evolution rate, which may be one of the reasons for periodic outbreaks in this area.
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Affiliation(s)
- Jun-Song Wu
- Department of Orthopaedics & Trauma Center of Emergency Medicine, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China.
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Feher VA, Randall A, Baldi P, Bush RM, de la Maza LM, Amaro RE. A 3-dimensional trimeric β-barrel model for Chlamydia MOMP contains conserved and novel elements of Gram-negative bacterial porins. PLoS One 2013; 8:e68934. [PMID: 23935908 PMCID: PMC3723809 DOI: 10.1371/journal.pone.0068934] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 06/04/2013] [Indexed: 01/17/2023] Open
Abstract
Chlamydia trachomatis is the most prevalent cause of bacterial sexually transmitted diseases and the leading cause of preventable blindness worldwide. Global control of Chlamydia will best be achieved with a vaccine, a primary target for which is the major outer membrane protein, MOMP, which comprises ~60% of the outer membrane protein mass of this bacterium. In the absence of experimental structural information on MOMP, three previously published topology models presumed a16-stranded barrel architecture. Here, we use the latest β-barrel prediction algorithms, previous 2D topology modeling results, and comparative modeling methodology to build a 3D model based on the 16-stranded, trimeric assumption. We find that while a 3D MOMP model captures many structural hallmarks of a trimeric 16-stranded β-barrel porin, and is consistent with most of the experimental evidence for MOMP, MOMP residues 320-334 cannot be modeled as β-strands that span the entire membrane, as is consistently observed in published 16-stranded β-barrel crystal structures. Given the ambiguous results for β-strand delineation found in this study, recent publications of membrane β-barrel structures breaking with the canonical rule for an even number of β-strands, findings of β-barrels with strand-exchanged oligomeric conformations, and alternate folds dependent upon the lifecycle of the bacterium, we suggest that although the MOMP porin structure incorporates canonical 16-stranded conformations, it may have novel oligomeric or dynamic structural changes accounting for the discrepancies observed.
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Affiliation(s)
- Victoria A. Feher
- Department Chemistry and Biochemistry, University of California San Diego, San Diego, California, United States of America
| | - Arlo Randall
- School of Information and Computer Sciences, University of California Irvine, Irvine, California, United States of America
- Institute for Genomics and Bioinformatics, University of California Irvine, Irvine, California, United States of America
| | - Pierre Baldi
- School of Information and Computer Sciences, University of California Irvine, Irvine, California, United States of America
- Institute for Genomics and Bioinformatics, University of California Irvine, Irvine, California, United States of America
| | - Robin M. Bush
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, California, United States of America
| | - Luis M. de la Maza
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, California, United States of America
| | - Rommie E. Amaro
- Department Chemistry and Biochemistry, University of California San Diego, San Diego, California, United States of America
- * E-mail:
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Rodríguez-Domínguez M, Puerta T, Menéndez B, González-Alba JM, Rodríguez C, Hellín T, Vera M, González-Sainz FJ, Clavo P, Villa M, Cantón R, Del Romero J, Galán JC. Clinical and epidemiological characterization of a lymphogranuloma venereum outbreak in Madrid, Spain: co-circulation of two variants. Clin Microbiol Infect 2013; 20:219-25. [PMID: 23730727 DOI: 10.1111/1469-0691.12256] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 04/04/2013] [Accepted: 04/23/2013] [Indexed: 11/28/2022]
Abstract
The lymphogranuloma venereum (LGV) outbreak described in the Netherlands in 2003, increased the interest in the genotyping of Chlamydia trachomatis. Although international surveillance programmes were implemented, these studies slowly decreased in the following years. Now data have revealed a new accumulation of LGV cases in those European countries with extended surveillance programmes. Between March 2009 and November 2011, a study was carried out to detect LGV cases in Madrid. The study was based on screening of C. trachomatis using commercial kits, followed by real-time pmpH-PCR discriminating LGV strains, and finally ompA gene was sequenced for phylogenetic reconstruction. Ninety-four LGV infections were identified. The number of cases increased from 10 to 30 and then to 54 during 2009-2011. Incidence of LGV was strongly associated with men who have sex with men; but in 2011, LGV cases were described in women and heterosexual men. Sixty-nine patients were also human immunodeficiency virus (HIV) positive, with detectable viral loads at the moment of LGV diagnosis, suggesting a high-risk of co-transmission. In fact, in four patients the diagnosis of HIV was simultaneous with LGV infection. The conventional treatment with doxycycline was prescribed in 75 patients, although in three patients the treatment failed. The sequencing of the ompA gene permitted identification of two independent transmission nodes. One constituted by 25 sequences identical to the L2b variant, and a second node including 37 sequences identical to L2. This epidemiological situation characterized by the co-circulation of two LGV variants has not been previously described, reinforcing the need for screening and genotyping of LGV strains.
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Affiliation(s)
- M Rodríguez-Domínguez
- Servicio de Microbiología and CIBER en Epidemiología y Salud Pública (CIBERESP), Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
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Nunes A, Borrego MJ, Gomes JP. Genomic features beyond Chlamydia trachomatis phenotypes: what do we think we know? INFECTION GENETICS AND EVOLUTION 2013; 16:392-400. [PMID: 23523596 DOI: 10.1016/j.meegid.2013.03.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 02/25/2013] [Accepted: 03/13/2013] [Indexed: 10/27/2022]
Abstract
The obligate intracellular pathogen Chlamydia trachomatis is the causative agent of the blinding trachoma and the world's leading cause of bacterial sexually transmitted infections. Despite aggressive antibacterial control measures, C. trachomatis infections have been increasing, constituting a serious public health concern due to its morbidity and socioeconomic burden. Still, very little is known about the molecular basis underlying the phenotypic disparities observed among C. trachomatis serovars in terms of tissue tropism (ocular conjunctiva, epithelial-genitalia and lymph nodes), virulence (disease outcomes) and ecological success. This is in part due to the inexistence of straightforward tools to genetically manipulate Chlamydiae and host cell-free growth systems, hampering the elucidation of the biological role of loci. The recent release of tenths of full-genome C. trachomatis sequences depict a strains clustering scenario reflecting the organ/cell-type that they preferentially infect. However, the high degree of genomic conservation implies that few genetic features are involved in phenotypic dissimilarities. The purpose of this review is to gather the most relevant data dispersed throughout the literature concerning the genotypic evidences that support niche-specific phenotypes. This review focus on chromosomal dynamics phenomena like recombination and point-mutations, essentially involving outer and inclusion membrane proteins, type III secretion effectors, and hypothetical proteins with unknown function. The scrutiny of C. trachomatis loci involved in tissue tropism, pathogenesis and ecological success is crucial for the development of disease-specific prophylaxis.
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Affiliation(s)
- Alexandra Nunes
- Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal.
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Grimm SK, Ackerman ME. Vaccine design: emerging concepts and renewed optimism. Curr Opin Biotechnol 2013; 24:1078-88. [PMID: 23474232 DOI: 10.1016/j.copbio.2013.02.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/29/2013] [Accepted: 02/15/2013] [Indexed: 01/15/2023]
Abstract
Arguably, vaccination represents the single most effective medical intervention ever developed. Yet, vaccines have failed to provide any or adequate protection against some of the most significant global diseases. The pathogens responsible for these vaccine-recalcitrant diseases have properties that allow them to evade immune surveillance and misdirect or eliminate the immune response. However, genomic and systems biology tools, novel adjuvants and delivery systems, and refined molecular insight into protective immunity have started to redefine the landscape, and results from recent efficacy trials of HIV and malaria vaccines have instilled hope that another golden age of vaccines may be on the horizon.
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Directional evolution of Chlamydia trachomatis towards niche-specific adaptation. J Bacteriol 2012; 194:6143-53. [PMID: 22961851 DOI: 10.1128/jb.01291-12] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
On behalf of the host-pathogen "arms race," a cutting-edge approach for elucidating genotype-phenotype relationships relies on the identification of positively selected loci involved in pathoadaptation. We studied the obligate intracellular bacterium Chlamydia trachomatis, for which same-species strains display a nearly identical core and pan genome, while presenting a wide range of tissue tropism and ecological success. We sought to evaluate the evolutionary patterns underlying species separation (divergence) and C. trachomatis serovar radiation (polymorphism) and to establish genotype-phenotype associations. By analyzing 60 Chlamydia strains, we detected traces of Muller's ratchet as a result of speciation and identified positively selected genes and codons hypothetically involved in the infection of different human cell types (e.g., columnar epithelial cells of ocular or genital mucosae and mononuclear phagocytes) and also events likely driving pathogenic and ecological success dissimilarities. In general, these genes code for proteins involved in immune response elicitation, proteolysis, and the subversion of host-cell functions, and also for proteins with unknown function(s). Several genes are potentially involved in more than one adaptive process, suggesting multiple functions or a distinct modus operandi for a specific function, and thus should be considered as crucial research targets. In addition, six of the nine genes encoding the putative antigen/adhesin polymorphic membrane proteins seem to be under positive selection along specific serovars, which sustains an essential biological role of this extra-large paralogue family in chlamydial pathobiology. This study provides insight into how evolutionary inferences illuminate ecological processes such as adaptation to different niches, pathogenicity, or ecological success driven by arms races.
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Impact of loci nature on estimating recombination and mutation rates in Chlamydia trachomatis. G3-GENES GENOMES GENETICS 2012; 2:761-8. [PMID: 22870399 PMCID: PMC3385982 DOI: 10.1534/g3.112.002923] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 05/03/2012] [Indexed: 02/06/2023]
Abstract
The knowledge of the frequency and relative weight of mutation and recombination events in evolution is essential for understanding how microorganisms reach fitted phenotypes. Traditionally, these evolutionary parameters have been inferred by using data from multilocus sequence typing (MLST), which is known to have yielded conflicting results. In the near future, these estimations will certainly be performed by computational analyses of full-genome sequences. However, it is not known whether this approach will yield accurate results as bacterial genomes exhibit heterogeneous representation of loci categories, and it is not clear how loci nature impacts such estimations. Therefore, we assessed how mutation and recombination inferences are shaped by loci with different genetic features, using the bacterium Chlamydia trachomatis as the study model. We found that loci assigning a high number of alleles and positively selected genes yielded nonconvergent estimates and incongruent phylogenies and thus are more prone to confound algorithms. Unexpectedly, for the model under evaluation, housekeeping genes and noncoding regions shaped estimations in a similar manner, which points to a nonrandom role of the latter in C. trachomatis evolution. Although the present results relate to a specific bacterium, we speculate that microbe-specific genomic architectures (such as coding capacity, polymorphism dispersion, and fraction of positively selected loci) may differentially buffer the effect of the confounding factors when estimating recombination and mutation rates and, thus, influence the accuracy of using full-genome sequences for such purpose. This putative bias associated with in silico inferences should be taken into account when discussing the results obtained by the analyses of full-genome sequences, in which the “one size fits all” approach may not be applicable.
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Santra S, Muldoon M, Watson S, Buzby A, Balachandran H, Carlson KR, Mach L, Kong WP, McKee K, Yang ZY, Rao SS, Mascola JR, Nabel GJ, Korber BT, Letvin NL. Breadth of cellular and humoral immune responses elicited in rhesus monkeys by multi-valent mosaic and consensus immunogens. Virology 2012; 428:121-7. [PMID: 22521913 DOI: 10.1016/j.virol.2012.03.012] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 03/12/2012] [Accepted: 03/22/2012] [Indexed: 12/01/2022]
Abstract
To create an HIV-1 vaccine that generates sufficient breadth of immune recognition to protect against the genetically diverse forms of the circulating virus, we have been exploring vaccines based on consensus and mosaic protein designs. Increasing the valency of a mosaic immunogen cocktail increases epitope coverage but with diminishing returns, as increasingly rare epitopes are incorporated into the mosaic proteins. In this study we compared the immunogenicity of 2-valent and 3-valent HIV-1 envelope mosaic immunogens in rhesus monkeys. Immunizations with the 3-valent mosaic immunogens resulted in a modest increase in the breadth of vaccine-elicited T lymphocyte responses compared to the 2-valent mosaic immunogens. However, the 3-valent mosaic immunogens elicited significantly higher neutralizing responses to Tier 1 viruses than the 2-valent mosaic immunogens. These findings underscore the potential utility of polyvalent mosaic immunogens for eliciting both cellular and humoral immune responses to HIV-1.
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Affiliation(s)
- Sampa Santra
- Division of Viral Pathogenesis, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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Joseph SJ, Didelot X, Gandhi K, Dean D, Read TD. Interplay of recombination and selection in the genomes of Chlamydia trachomatis. Biol Direct 2011; 6:28. [PMID: 21615910 PMCID: PMC3126793 DOI: 10.1186/1745-6150-6-28] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 05/26/2011] [Indexed: 02/02/2023] Open
Abstract
Background Chlamydia trachomatis is an obligate intracellular bacterial parasite, which causes several severe and debilitating diseases in humans. This study uses comparative genomic analyses of 12 complete published C. trachomatis genomes to assess the contribution of recombination and selection in this pathogen and to understand the major evolutionary forces acting on the genome of this bacterium. Results The conserved core genes of C. trachomatis are a large proportion of the pan-genome: we identified 836 core genes in C. trachomatis out of a range of 874-927 total genes in each genome. The ratio of recombination events compared to mutation (ρ/θ) was 0.07 based on ancestral reconstructions using the ClonalFrame tool, but recombination had a significant effect on genetic diversification (r/m = 0.71). The distance-dependent decay of linkage disequilibrium also indicated that C. trachomatis populations behaved intermediately between sexual and clonal extremes. Fifty-five genes were identified as having a history of recombination and 92 were under positive selection based on statistical tests. Twenty-three genes showed evidence of being under both positive selection and recombination, which included genes with a known role in virulence and pathogencity (e.g., ompA, pmps, tarp). Analysis of inter-clade recombination flux indicated non-uniform currents of recombination between clades, which suggests the possibility of spatial population structure in C. trachomatis infections. Conclusions C. trachomatis is the archetype of a bacterial species where recombination is relatively frequent yet gene gains by horizontal gene transfer (HGT) and losses (by deletion) are rare. Gene conversion occurs at sites across the whole C. trachomatis genome but may be more often fixed in genes that are under diversifying selection. Furthermore, genome sequencing will reveal patterns of serotype specific gene exchange and selection that will generate important research questions for understanding C. trachomatis pathogenesis. Reviewers This article was reviewed by Dr. Jeremy Selengut, Dr. Lee S. Katz (nominated by Dr. I. King Jordan) and Dr. Arcady Mushegian.
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Affiliation(s)
- Sandeep J Joseph
- Department of Medicine, Division of Infectious, Diseases Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
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Beare PA, Sandoz KM, Omsland A, Rockey DD, Heinzen RA. Advances in genetic manipulation of obligate intracellular bacterial pathogens. Front Microbiol 2011; 2:97. [PMID: 21833334 PMCID: PMC3153054 DOI: 10.3389/fmicb.2011.00097] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 04/19/2011] [Indexed: 11/22/2022] Open
Abstract
Infections by obligate intracellular bacterial pathogens result in significant morbidity and mortality worldwide. These bacteria include Chlamydia spp., which causes millions of cases of sexually transmitted disease and blinding trachoma annually, and members of the α-proteobacterial genera Anaplasma, Ehrlichia, Orientia, and Rickettsia, agents of serious human illnesses including epidemic typhus. Coxiella burnetii, the agent of human Q fever, has also been considered a prototypical obligate intracellular bacterium, but recent host cell-free (axenic) growth has rescued it from obligatism. The historic genetic intractability of obligate intracellular bacteria has severely limited molecular dissection of their unique lifestyles and virulence factors involved in pathogenesis. Host cell restricted growth is a significant barrier to genetic transformation that can make simple procedures for free-living bacteria, such as cloning, exceedingly difficult. Low transformation efficiency requiring long-term culture in host cells to expand small transformant populations is another obstacle. Despite numerous technical limitations, the last decade has witnessed significant gains in genetic manipulation of obligate intracellular bacteria including allelic exchange. Continued development of genetic tools should soon enable routine mutation and complementation strategies for virulence factor discovery and stimulate renewed interest in these refractory pathogens. In this review, we discuss the technical challenges associated with genetic transformation of obligate intracellular bacteria and highlight advances made with individual genera.
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Affiliation(s)
- Paul A Beare
- Coxiella Pathogenesis Section, Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health Hamilton, MT, USA
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Gall A, Horowitz A, Joof H, Natividad A, Tetteh K, Riley E, Bailey RL, Mabey DCW, Holland MJ. Systemic effector and regulatory immune responses to chlamydial antigens in trachomatous trichiasis. Front Microbiol 2011; 2:10. [PMID: 21747780 PMCID: PMC3128932 DOI: 10.3389/fmicb.2011.00010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 01/18/2011] [Indexed: 12/24/2022] Open
Abstract
Trachomatous trichiasis (TT) caused by repeated or chronic ocular infection with Chlamydia trachomatis is the result of a pro-fibrotic ocular immune response. At the conjunctiva, the increased expression of both inflammatory (IL1B, TNF) and regulatory cytokines (IL10) have been associated with adverse clinical outcomes. We measured in vitro immune responses of peripheral blood to a number of chlamydial antigens. Peripheral blood effector cells (CD4, CD69, IFNγ, IL-10) and regulatory cells (CD4, CD25, FOXP3, CTLA4/GITR) were readily stimulated by C. trachomatis antigens but neither the magnitude (frequency or stimulation index) or the breadth and amount of cytokines produced in vitro [IL-5, IL-10, IL-12 (p70), IL-13, IFNγ, and TNFα] were significantly different between TT cases and their non-diseased controls. Interestingly we observed that CD4+ T cells account for <50% of the IFNγ positive cells induced following stimulation. Further investigation in individuals selected from communities where exposure to ocular infection with C. trachomatis is endemic indicated that CD3-CD56+ (classical natural killer cells) were a major early source of IFNγ production in response to C. trachomatis elementary body stimulation and that the magnitude of this response increased with age. Future efforts to unravel the contribution of the adaptive immune response to conjunctival fibrosis should focus on the early events following infection and the interaction with innate immune mediated mechanisms of inflammation in the conjunctiva.
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Affiliation(s)
- Alevtina Gall
- Viral Diseases Programme, Medical Research Council Laboratories Banjul, The Gambia
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