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Delgado KN, Caimano MJ, Orbe IC, Vicente CF, La Vake CJ, Grassmann AA, Moody MA, Radolf JD, Hawley KL. Immunodominant extracellular loops of Treponema pallidum FadL outer membrane proteins elicit antibodies with opsonic and growth-inhibitory activities. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.30.605823. [PMID: 39131275 PMCID: PMC11312542 DOI: 10.1101/2024.07.30.605823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
The global resurgence of syphilis has created a potent stimulus for vaccine development. To identify potentially protective antibodies (Abs) against Treponema pallidum (TPA), we used Pyrococcus furiosus thioredoxin (PfTrx) to display extracellular loops (ECLs) from three TPA outer membrane protein families (outer membrane factors for efflux pumps, eight-stranded β-barrels, and FadLs) to assess their reactivity with immune rabbit serum (IRS). Five ECLs from the FadL orthologs TP0856, TP0858 and TP0865 were immunodominant. Rabbits and mice immunized with these five PfTrx constructs produced ECL-specific Abs that promoted opsonophagocytosis of TPA by rabbit peritoneal and murine bone marrow-derived macrophages at levels comparable to IRS and mouse syphilitic serum. ECL-specific rabbit and mouse Abs also impaired viability, motility, and cellular attachment of spirochetes during in vitro cultivation. The results support the use of ECL-based vaccines and suggest that ECL-specific Abs promote spirochete clearance via Fc receptor-independent as well as Fc receptor-dependent mechanisms.
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Affiliation(s)
- Kristina N Delgado
- Department of Medicine, UConn Health, Farmington, Connecticut, United States
| | - Melissa J Caimano
- Department of Medicine, UConn Health, Farmington, Connecticut, United States
- Department of Pediatrics, UConn Health, Farmington, CT, United States
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, United States
- Department of Research, Connecticut Children's Research Institute, Hartford, CT, United States
| | - Isabel C Orbe
- Department of Pediatrics, UConn Health, Farmington, CT, United States
| | - Crystal F Vicente
- Department of Pediatrics, UConn Health, Farmington, CT, United States
| | - Carson J La Vake
- Department of Pediatrics, UConn Health, Farmington, CT, United States
| | - André A Grassmann
- Department of Medicine, UConn Health, Farmington, Connecticut, United States
| | - M Anthony Moody
- Duke Human Vaccine Institute, Durham, NC, United States
- Department of Pediatrics, Duke University Medical Center, Durham, NC, United States
- Department of Immunology, Duke University Medical Center, Durham, NC, United States
| | - Justin D Radolf
- Department of Medicine, UConn Health, Farmington, Connecticut, United States
- Department of Pediatrics, UConn Health, Farmington, CT, United States
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, United States
- Department of Research, Connecticut Children's Research Institute, Hartford, CT, United States
- Department of Immunology, UConn Health, Farmington, CT, United States
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, United States
| | - Kelly L Hawley
- Department of Medicine, UConn Health, Farmington, Connecticut, United States
- Department of Pediatrics, UConn Health, Farmington, CT, United States
- Department of Research, Connecticut Children's Research Institute, Hartford, CT, United States
- Department of Immunology, UConn Health, Farmington, CT, United States
- Division of Infectious Diseases and Immunology, Connecticut Children's, Hartford, CT, United States
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2
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Houston S, Gomez A, Geppert A, Goodyear MC, Cameron CE. In-Depth Proteome Coverage of In Vitro-Cultured Treponema pallidum and Quantitative Comparison Analyses with In Vivo-Grown Treponemes. J Proteome Res 2024; 23:1725-1743. [PMID: 38636938 PMCID: PMC11077495 DOI: 10.1021/acs.jproteome.3c00891] [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: 12/15/2023] [Revised: 03/14/2024] [Accepted: 03/22/2024] [Indexed: 04/20/2024]
Abstract
Previous mass spectrometry (MS)-based global proteomics studies have detected a combined total of 86% of all Treponema pallidum proteins under infection conditions (in vivo-grown T. pallidum). Recently, a method was developed for the long-term culture of T. pallidum under in vitro conditions (in vitro-cultured T. pallidum). Herein, we used our previously reported optimized MS-based proteomics approach to characterize the T. pallidum global protein expression profile under in vitro culture conditions. These analyses provided a proteome coverage of 94%, which extends the combined T. pallidum proteome coverage from the previously reported 86% to a new combined total of 95%. This study provides a more complete understanding of the protein repertoire of T. pallidum. Further, comparison of the in vitro-expressed proteome with the previously determined in vivo-expressed proteome identifies only a few proteomic changes between the two growth conditions, reinforcing the suitability of in vitro-cultured T. pallidum as an alternative to rabbit-based treponemal growth. The MS proteomics data have been deposited in the MassIVE repository with the data set identifier MSV000093603 (ProteomeXchange identifier PXD047625).
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Affiliation(s)
- Simon Houston
- Department
of Biochemistry and Microbiology, University
of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Alloysius Gomez
- Department
of Biochemistry and Microbiology, University
of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Andrew Geppert
- Department
of Biochemistry and Microbiology, University
of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Mara C. Goodyear
- Department
of Biochemistry and Microbiology, University
of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Caroline E. Cameron
- Department
of Biochemistry and Microbiology, University
of Victoria, Victoria, British Columbia V8P 5C2, Canada
- Department
of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington 98195, United States
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3
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Adhikari EH. Update on syphilis in pregnancy: marrying basic science advances and clinical perseverance to solve an ancient public health problem. Curr Opin Obstet Gynecol 2024; 36:67-74. [PMID: 38205786 DOI: 10.1097/gco.0000000000000939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
PURPOSE OF REVIEW While the clinical disease of syphilis, its consequences in pregnancy, and its sensitivity to penicillin treatment have remained relatively unchanged for a century or more, new technologies and basic discoveries in syphilis research have translated into tangible advances in clinical diagnosis, treatment, and prevention. The purpose of this review is to help the reader understand some of the recent relevant scientific publications on syphilis and its causative organism in a clinical obstetric context. RECENT FINDINGS Rates of adult and congenital syphilis have risen dramatically in the last decade despite public health efforts. Penicillin shortages and lack of screening or adequate treatment have all contributed to global disease burden. Advances in genomic and microbiological characterization of this spirochete have led to new developments in serologic and molecular diagnosis as well as evaluation of potential vaccine candidates. Until a syphilis vaccine is available, substance use disorders and lack of screening in pregnancy are associated with increased congenital syphilis, and these challenges will require novel solutions to fully address this public health crisis. SUMMARY Addressing the burden of congenital syphilis demands that obstetricians stay well informed of new tools and resources for diagnosis, treatment, and prevention of syphilis now and in the future.
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Affiliation(s)
- Emily H Adhikari
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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4
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Houston S, Gomez A, Geppert A, Eshghi A, Smith DS, Waugh S, Hardie DB, Goodlett DR, Cameron CE. Deep proteome coverage advances knowledge of Treponema pallidum protein expression profiles during infection. Sci Rep 2023; 13:18259. [PMID: 37880309 PMCID: PMC10600179 DOI: 10.1038/s41598-023-45219-8] [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: 06/19/2023] [Accepted: 10/17/2023] [Indexed: 10/27/2023] Open
Abstract
Comprehensive proteome-wide analysis of the syphilis spirochete, Treponema pallidum ssp. pallidum, is technically challenging due to high sample complexity, difficulties with obtaining sufficient quantities of bacteria for analysis, and the inherent fragility of the T. pallidum cell envelope which further complicates proteomic identification of rare T. pallidum outer membrane proteins (OMPs). The main aim of the present study was to gain a deeper understanding of the T. pallidum global proteome expression profile under infection conditions. This will corroborate and extend genome annotations, identify protein modifications that are unable to be predicted at the genomic or transcriptomic levels, and provide a foundational knowledge of the T. pallidum protein expression repertoire. Here we describe the optimization of a T. pallidum-specific sample preparation workflow and mass spectrometry-based proteomics pipeline which allowed for the detection of 77% of the T. pallidum protein repertoire under infection conditions. When combined with prior studies, this brings the overall coverage of the T. pallidum proteome to almost 90%. These investigations identified 27 known/predicted OMPs, including potential vaccine candidates, and detected expression of 11 potential OMPs under infection conditions for the first time. The optimized pipeline provides a robust and reproducible workflow for investigating T. pallidum protein expression during infection. Importantly, the combined results provide the deepest coverage of the T. pallidum proteome to date.
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Affiliation(s)
- Simon Houston
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Alloysius Gomez
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Andrew Geppert
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Azad Eshghi
- University of Victoria-Genome BC Proteomics Centre, University of Victoria, Victoria, BC, Canada
| | - Derek S Smith
- University of Victoria-Genome BC Proteomics Centre, University of Victoria, Victoria, BC, Canada
| | - Sean Waugh
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Darryl B Hardie
- University of Victoria-Genome BC Proteomics Centre, University of Victoria, Victoria, BC, Canada
| | - David R Goodlett
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
- University of Victoria-Genome BC Proteomics Centre, University of Victoria, Victoria, BC, Canada
| | - Caroline E Cameron
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada.
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA.
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Liu D, Chen R, Wang YJ, Li W, Liu LL, Lin LR, Yang TC, Tong ML. Insights into the protective immune response by immunization with full-length recombinant TprK protein: cellular and humoral responses. NPJ Vaccines 2023; 8:146. [PMID: 37773233 PMCID: PMC10542339 DOI: 10.1038/s41541-023-00748-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 09/19/2023] [Indexed: 10/01/2023] Open
Abstract
Syphilis has resurged in many countries, which has called attention to vaccine development. Based on the immunization-based rabbit model of infection with the Nichols strain, this study explored the protective immune response of a controversial syphilis vaccine candidate, TprK, and found that immunization with full-length rTprK was effective in attenuating lesion development and accelerating lesion resolution, which could reduce the probability of the pathogen spreading to distant tissue sites to prevent the progression of the disease to some extent. Furthermore, the results revealed that immunization with rTprK not only rapidly induced a strong Th1-like cellular response but also elicited a humoral immune response to produce opsonic antibodies to enhance macrophage-mediated opsonophagocytosis. Although complete protection against infection was not achieved, the study provided a comprehensive and in-depth exploration of the immunogenicity of TprK and highlighted the importance of TprK as a promising syphilis vaccine component.
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Affiliation(s)
- Dan Liu
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Rui Chen
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Yong-Jing Wang
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Wei Li
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Li-Li Liu
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Li-Rong Lin
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Tian-Ci Yang
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China.
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China.
| | - Man-Li Tong
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China.
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China.
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6
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Liu D, Chen R, He Y, Wang YJ, Lin LR, Liu LL, Yang TC, Tong ML. Longitudinal Variations in the tprK Gene of Treponema pallidum in an Amoy Strain-Infected Rabbit Model. Microbiol Spectr 2023; 11:e0106723. [PMID: 37347187 PMCID: PMC10433980 DOI: 10.1128/spectrum.01067-23] [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: 03/12/2023] [Accepted: 06/01/2023] [Indexed: 06/23/2023] Open
Abstract
Heterogeneous tprK sequences have been hypothesized to be an important factor for persistent infection of Treponema pallidum subsp. pallidum (T. pallidum) in humans. Previous research has only explored tprK diversity using a rabbit model infected with almost clonal isolates, which is inconsistent with the fact that infected human isolates contain multiple heterogeneous tprK sequences. Here, we used the T. pallidum Amoy strain with heterogeneous tprK sequences to establish a rabbit infection model and explore longitudinal variations in the tprK gene under normal infection, immunosuppression treatment, and benzathine penicillin G (BPG) treatment using next-generation sequencing. The diversity of the tprK gene was high in all three groups but was highest in the control group and lowest in the BPG group. Interestingly, the overall diversity of tprK in all three groups decreased during infection, exhibiting a "more to less" trend, indicating that survival selection may be an important factor affecting tprK variation in the later infection stage. BPG treatment appeared to reduce the diversity of tprK but increased the frequency of predominant sequence changes, which might facilitate the escape of T. pallidum from the host immune clearance. Furthermore, the original predominant V region sequence did not disappear with disease progression but retained a relatively high proportion within the population, suggesting a new direction for tprK-related vaccine research. This study provides insights into longitudinal variations within the highly heterogeneous tprK gene sequences of T. pallidum and will contribute to further exploration of the pathogenesis of syphilis. IMPORTANCE The tprK variations are an important factor in persistent T. pallidum infection. A nearly clonal isolate has been used previously to investigate the mechanism of tprK gene variations; however, clinical T. pallidum isolates in infected humans exhibit multiple heterogeneous tprK sequences. Here, we use next-generation sequencing to explore longitudinal variations in the tprK gene under normal infection and immunosuppression and benzathine penicillin G treatment in a rabbit model infected with the Amoy strain with heterogeneous tprK sequences. The overall diversity of tprK in all three groups was high and decreased during infection, exhibiting a "more to less" trend. Benzathine penicillin G treatment reduced the diversity of tprK but increased the frequency of predominant sequence changes. Moreover, the original predominant V region sequence did not disappear as the disease progressed but remained at a relatively high proportion within the population. The research results give us a new understanding about tprK variation.
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Affiliation(s)
- Dan Liu
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Rui Chen
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Yun He
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Yong-jing Wang
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Li-Rong Lin
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Li-Li Liu
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Tian-Ci Yang
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Man-Li Tong
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
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7
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Liu D, Liu LL, Zheng XQ, Chen R, Lin LR, Yang TC, Tong ML. Genetic Profiling of the Full-Length tprK Gene in Patients with Primary and Secondary Syphilis. Microbiol Spectr 2023; 11:e0493122. [PMID: 37036342 PMCID: PMC10269439 DOI: 10.1128/spectrum.04931-22] [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: 11/30/2022] [Accepted: 03/17/2023] [Indexed: 04/11/2023] Open
Abstract
TprK antigenic variation is acknowledged as an important strategy developed by Treponema pallidum to achieve immune evasion. Previous studies applied short-read sequencing to explore tprK gene sequence diversity in clinical samples; however, due to the limitations of short-read sequencing, it was difficult to determine the linkage between the seven V regions, and crucial information about full-length tprK variants was lost. Although two recent studies explored complete tprK gene profiles in natural human syphilis infection, there are still too few profiled full-length tprK variants among clinical T. pallidum isolates to fully understand the characteristics of TprK coding diversity. Here, Pacific Biosciences (PacBio) long-read sequencing was applied to examine the diversity of full-length tprK variants in 21 clinical T. pallidum isolates from 11 patients with primary syphilis and 10 patients with secondary syphilis. A total of 398 high-confidence full-length sequences, which presented remarkable sequence heterogeneity, were found. However, these full-length tprK variants exhibited limited variation in length and GC content, showing 24 length types and average GC content of 51.5 ± 0.42% and 51.6 ± 0.26% for primary and secondary syphilis samples, respectively. Additionally, the combined patterns of mutated V regions generating new tprK variants were obviously different in primary and secondary syphilis samples. The diversity of tprK gene sequences in primary syphilis samples may represent the underlying variability of the bacterium; conversely, the variability of the tprK gene in secondary syphilis samples may more accurately reflect how T. pallidum escapes host immune clearance. These data highlight the tprK gene as an important coding gene that shows conflicting genetic characteristics but underlies the persistence of spirochete infection. IMPORTANCE The resurgence of syphilis in both low- and high-income countries has attracted attention, and persistent infection by the pathogen has long been a research focus. The tprK gene, encoding the hypervariable outer membrane protein, is thought to be responsible for pathogen immune evasion and persistent infection. Here, PacBio long-read sequencing was applied to examine the diversity of full-length tprK variants in 21 clinical T. pallidum isolates from 11 patients with primary syphilis and 10 patients with secondary syphilis. The results showed that the sequences of the tprK gene were remarkably heterogeneous; however, the sequences presented limited variation in length and GC content. The investigation of the combined patterns of the V regions allowed us to gain insight into the features of the tprK gene generating new variants at different clinical stages. The findings of this study will be helpful for further exploration of the pathogenesis of syphilis.
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Affiliation(s)
- Dan Liu
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Li-Li Liu
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Xin-Qi Zheng
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Rui Chen
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Li-Rong Lin
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Tian-Ci Yang
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Man-Li Tong
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
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8
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Ávila-Nieto C, Pedreño-López N, Mitjà O, Clotet B, Blanco J, Carrillo J. Syphilis vaccine: challenges, controversies and opportunities. Front Immunol 2023; 14:1126170. [PMID: 37090699 PMCID: PMC10118025 DOI: 10.3389/fimmu.2023.1126170] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 03/27/2023] [Indexed: 04/25/2023] Open
Abstract
Syphilis is a sexually or vertically (mother to fetus) transmitted disease caused by the infection of Treponema pallidum subspecie pallidum (TPA). The incidence of syphilis has increased over the past years despite the fact that this bacterium is an obligate human pathogen, the infection route is well known, and the disease can be successfully treated with penicillin. As complementary measures to preventive campaigns and early treatment of infected individuals, development of a syphilis vaccine may be crucial for controlling disease spread and/or severity, particularly in countries where the effectiveness of the aforementioned measures is limited. In the last century, several vaccine prototypes have been tested in preclinical studies, mainly in rabbits. While none of them provided protection against infection, some prototypes prevented bacteria from disseminating to distal organs, attenuated lesion development, and accelerated their healing. In spite of these promising results, there is still some controversy regarding the identification of vaccine candidates and the characteristics of a syphilis-protective immune response. In this review, we describe what is known about TPA immune response, and the main mechanisms used by this pathogen to evade it. Moreover, we emphasize the importance of integrating this knowledge, in conjunction with the characterization of outer membrane proteins (OMPs), to expedite the development of a syphilis vaccine that can protect against TPA infection.
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Affiliation(s)
- Carlos Ávila-Nieto
- IrsiCaixa AIDS Research Institute, Badalona, Spain
- Autonomous University of Barcelona, Cerdanyola del Vallès, Catalonia, Spain
| | | | - Oriol Mitjà
- Skin Neglected Tropical Diseases and Sexually Transmitted Infections Department, Germans Trias i Pujol Hospital, Badalona, Spain
- Fight Infections Foundation, Germans Trias i Pujol Hospital, Badalona, Catalonia, Spain
- Centre for Health and Social Care Research (CESS), Faculty of Medicine, University of Vic – Central University of Catalonia (UVic – UCC), Vic, Catalonia, Spain
| | - Bonaventura Clotet
- IrsiCaixa AIDS Research Institute, Badalona, Spain
- Fight Infections Foundation, Germans Trias i Pujol Hospital, Badalona, Catalonia, Spain
- Centre for Health and Social Care Research (CESS), Faculty of Medicine, University of Vic – Central University of Catalonia (UVic – UCC), Vic, Catalonia, Spain
- Germans Trias i Pujol Research Institute (IGTP), Badalona, Spain
- CIBERINFEC, Instituto de Salut Carlos III (ISCIII), Madrid, Spain
| | - Julià Blanco
- IrsiCaixa AIDS Research Institute, Badalona, Spain
- Centre for Health and Social Care Research (CESS), Faculty of Medicine, University of Vic – Central University of Catalonia (UVic – UCC), Vic, Catalonia, Spain
- Germans Trias i Pujol Research Institute (IGTP), Badalona, Spain
- CIBERINFEC, Instituto de Salut Carlos III (ISCIII), Madrid, Spain
| | - Jorge Carrillo
- IrsiCaixa AIDS Research Institute, Badalona, Spain
- Germans Trias i Pujol Research Institute (IGTP), Badalona, Spain
- CIBERINFEC, Instituto de Salut Carlos III (ISCIII), Madrid, Spain
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9
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Lukehart SA, Molini B, Gomez A, Godornes C, Hof R, Fernandez MC, Pitner RA, Gray SA, Carter D, Giacani L, Cameron CE. Immunization with a tri-antigen syphilis vaccine significantly attenuates chancre development, reduces bacterial load, and inhibits dissemination of Treponema pallidum. Vaccine 2022; 40:7676-7692. [PMID: 36376214 DOI: 10.1016/j.vaccine.2022.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 10/31/2022] [Accepted: 11/01/2022] [Indexed: 11/13/2022]
Abstract
Syphilis continues to be a significant public health concern worldwide. The disease is endemic in many low- and middle-income countries, and rates have risen sharply in high-income countries over the last decade. The continued prevalence of infectious and congenital syphilis worldwide highlights the need for the development of an effective syphilis vaccine to complement public health measures for syphilis control. The complex, multi-stage course of syphilis infection necessitates a holistic approach to the development of an effective vaccine, in which immunization prevents both the localized stage of infection (typified by the highly infectious chancre) and the disseminated stages of infection (typified by the secondary rash, neurosyphilis, and destructive tertiary lesions, as well as congenital syphilis). Inhibiting development of the infectious chancre would reduce transmission thus providing community- level protection, while preventing dissemination would provide individual-level protection by reducing serious sequelae and may also provide community level protection by reducing shedding during secondary syphilis. In the current study we build upon prior investigations which demonstrated that immunizations with individual, well characterized T. pallidum TprK, TprC, and Tp0751 peptides elicits partial protection against infection in the animal model. Specifically, we show here that immunization with a TprC/TprK/Tp0751 tri-antigen cocktail protects animals from progressive syphilis lesions and substantially inhibits dissemination of the infection.
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Affiliation(s)
- Sheila A Lukehart
- Department of Medicine, Division of Allergy & Infectious Diseases, University of Washington, Seattle, WA, USA; Department of Global Health, University of Washington, Seattle, WA, USA
| | - Barbara Molini
- Department of Medicine, Division of Allergy & Infectious Diseases, University of Washington, Seattle, WA, USA
| | - Alloysius Gomez
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Charmie Godornes
- Department of Medicine, Division of Allergy & Infectious Diseases, University of Washington, Seattle, WA, USA
| | - Rebecca Hof
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Mark C Fernandez
- Department of Medicine, Division of Allergy & Infectious Diseases, University of Washington, Seattle, WA, USA
| | | | | | | | - Lorenzo Giacani
- Department of Medicine, Division of Allergy & Infectious Diseases, University of Washington, Seattle, WA, USA
| | - Caroline E Cameron
- Department of Medicine, Division of Allergy & Infectious Diseases, University of Washington, Seattle, WA, USA; Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada.
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10
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Tang Y, Zhou Y, He B, Cao T, Zhou X, Ning L, Chen E, Li Y, Xie X, Peng B, Hu Y, Liu S. Investigation of the immune escape mechanism of Treponema pallidum. Infection 2022; 51:305-321. [PMID: 36260281 DOI: 10.1007/s15010-022-01939-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 10/07/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND Syphilis is a chronic sexually transmitted disease caused by Treponema pallidum subspecies pallidum (T. pallidum), which is a public health problem that seriously affects human health worldwide. T. pallidum is characterized by early transmission and immune escape and is therefore termed an "invisible pathogen". METHODS This review systematically summarizes the host's innate and adaptive immune responses to T. pallidum infection as well as the escape mechanisms of T. pallidum. PURPOSE To lay the foundation for assessing the pathogenic mechanism and the systematic prevention and treatment of syphilis. CONCLUSION The immune escape mechanism of T. pallidum plays an important role in its survival. Exploring the occurrence and development of these mechanisms has laid the foundation for the development of syphilis vaccine.
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Affiliation(s)
- Yun Tang
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, Hengyang Medical School, The First Affiliated Hospital, University of South China, No. 69, Chuanshan Road, Hengyang City, 421000, Hunan, China
| | - Yingjie Zhou
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, Hengyang Medical School, The First Affiliated Hospital, University of South China, No. 69, Chuanshan Road, Hengyang City, 421000, Hunan, China
| | - Bisha He
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, Hengyang Medical School, The First Affiliated Hospital, University of South China, No. 69, Chuanshan Road, Hengyang City, 421000, Hunan, China
| | - Ting Cao
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, Hengyang Medical School, The First Affiliated Hospital, University of South China, No. 69, Chuanshan Road, Hengyang City, 421000, Hunan, China
| | - Xiangping Zhou
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, Hengyang Medical School, The First Affiliated Hospital, University of South China, No. 69, Chuanshan Road, Hengyang City, 421000, Hunan, China
| | - Lichang Ning
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, Hengyang Medical School, The First Affiliated Hospital, University of South China, No. 69, Chuanshan Road, Hengyang City, 421000, Hunan, China
| | - En Chen
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, Hengyang Medical School, The First Affiliated Hospital, University of South China, No. 69, Chuanshan Road, Hengyang City, 421000, Hunan, China
| | - Yumeng Li
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, Hengyang Medical School, The First Affiliated Hospital, University of South China, No. 69, Chuanshan Road, Hengyang City, 421000, Hunan, China
| | - Xiaoping Xie
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, Hengyang Medical School, The First Affiliated Hospital, University of South China, No. 69, Chuanshan Road, Hengyang City, 421000, Hunan, China
| | - Binfeng Peng
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, Hengyang Medical School, The First Affiliated Hospital, University of South China, No. 69, Chuanshan Road, Hengyang City, 421000, Hunan, China
| | - Yibao Hu
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, Hengyang Medical School, The First Affiliated Hospital, University of South China, No. 69, Chuanshan Road, Hengyang City, 421000, Hunan, China
| | - Shuangquan Liu
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, Hengyang Medical School, The First Affiliated Hospital, University of South China, No. 69, Chuanshan Road, Hengyang City, 421000, Hunan, China.
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11
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Kojima N, Konda KA, Klausner JD. Notes on syphilis vaccine development. Front Immunol 2022; 13:952284. [PMID: 35967432 PMCID: PMC9365935 DOI: 10.3389/fimmu.2022.952284] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 06/30/2022] [Indexed: 11/13/2022] Open
Abstract
The quest for a syphilis vaccine to provide protection from infection or disease began not long after the isolation of the first Treponema pallidum subspecies pallidum (T. pallidum) strain in 1912. Yet, a practical and effective vaccine formulation continues to elude scientists. Over the last few years, however, efforts toward developing a syphilis vaccine have increased thanks to an improved understanding of the repertoire of T. pallidum outer membrane proteins (OMPs), which are the most likely syphilis vaccine candidates. More has been also learned about the molecular mechanisms behind pathogen persistence and immune evasion. Published vaccine formulations based on a subset of the pathogen's OMPs have conferred only partial protection upon challenge of immunized laboratory animals, primarily rabbits. Nonetheless, those experiments have improved our approach to the choice of immunization regimens, adjuvants, and vaccine target selection, although significant knowledge gaps remain. Herein, we provide a brief overview on current technologies and approaches employed in syphilis vaccinology, and possible future directions to develop a vaccine that could be pivotal to future syphilis control and elimination initiatives.
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Affiliation(s)
- Noah Kojima
- Department of Medicine, University of California Los Angeles, Los Angeles, CA, United States
| | - Kelika A. Konda
- Department of Medicine, University of California Los Angeles, Los Angeles, CA, United States
- Centro de Investigación Interdisciplinaria en Sexualidad Sida y Sociedad, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Jeffrey D. Klausner
- Departments of Medicine and Population and Public Health Sciences, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States
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12
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Molini B, Fernandez MC, Godornes C, Vorobieva A, Lukehart SA, Giacani L. B-Cell Epitope Mapping of TprC and TprD Variants of Treponema pallidum Subspecies Informs Vaccine Development for Human Treponematoses. Front Immunol 2022; 13:862491. [PMID: 35422800 PMCID: PMC9001972 DOI: 10.3389/fimmu.2022.862491] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/07/2022] [Indexed: 12/02/2022] Open
Abstract
Several recent studies have focused on the identification, functional analysis, and structural characterization of outer membrane proteins (OMPs) of Treponema pallidum (Tp). The Tp species encompasses the highly related pallidum, pertenue, and endemicum subspecies of this pathogen, known to be the causative agents of syphilis, yaws, and bejel, respectively. These studies highlighted the importance of identifying surface-exposed OMP regions and the identification of B-cell epitopes that could be protective and used in vaccine development efforts. We previously reported that the TprC and TprD OMPs of Tp are predicted to contain external loops scattered throughout the entire length of the proteins, several of which show a low degree of sequence variability among strains and subspecies. In this study, these models were corroborated using AlphaFold2, a state-of-the-art protein structure modeling software. Here, we identified B-cell epitopes across the full-length TprC and TprD variants using the Geysan pepscan mapping approach with antisera from rabbits infected with syphilis, yaws, and bejel strains and from animals immunized with refolded recombinant TprC proteins from three syphilis strains. Our results show that the humoral response is primarily directed to sequences predicted to be on surface-exposed loops of TprC and TprD proteins, and that the magnitude of the humoral response to individual epitopes differs among animals infected with various syphilis strains and Tp subspecies. Rather than exhibiting strain-specificity, antisera showed various degrees of cross-reactivity with variant sequences from other strains. The data support the further exploration of TprC and TprD as vaccine candidates.
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Affiliation(s)
- Barbara Molini
- Department of Medicine, University of Washington, Seattle, WA, United States
| | - Mark C. Fernandez
- Department of Medicine, University of Washington, Seattle, WA, United States
| | - Charmie Godornes
- Department of Medicine, University of Washington, Seattle, WA, United States
| | - Anastassia Vorobieva
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Sheila A. Lukehart
- Department of Medicine, University of Washington, Seattle, WA, United States
- Department of Global Health, University of Washington, Seattle, WA, United States
| | - Lorenzo Giacani
- Department of Medicine, University of Washington, Seattle, WA, United States
- Department of Global Health, University of Washington, Seattle, WA, United States
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13
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Lian T, Zhang B, Giacani L, Kou C, Yang X, Zhang R, Wang Q. Full-length TprK of Treponema pallidum subsp. pallidum in lipid nanodiscs is a monomeric porin. Enzyme Microb Technol 2022; 153:109897. [PMID: 34670182 PMCID: PMC10929906 DOI: 10.1016/j.enzmictec.2021.109897] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/27/2021] [Accepted: 08/23/2021] [Indexed: 11/22/2022]
Abstract
TprK is a key virulence factor of Treponema pallidum subsp. pallidum (T. pallidum) due to its ability to undergo intra-strain antigenic variation through gene conversion. This mechanism can generate millions of tprK gene and protein variants to allow immune evasion and pathogen persistence during infection. In silico structural modeling supports that TprK is an outer membrane β-barrel with porin function and with several surface-exposed loops, seven of which corresponding to the variable regions. No definitive structural of functional data, however, exist for this protein aside from its role in immune evasion. Studies to elucidate TprK biological function as a porin, are hindered by the evidence that TprK is not abundant on T. pallidum outer membrane, and by the fragility of T. pallidum envelope. To gain insight onto TprK structure and possible function as a porin, we used an Escherichia coli - based expression system that yielded highly pure full-length TprK without any intermediate denaturation step, and proceeded to reconstitute it in detergents and lipid nanodiscs. Visualization of TprK in nanodiscs using negative staining electron microscopy supported that TprK is a monomeric porin in an artificial lipid environment mimicking T. pallidum membrane. Our work provided evidence that TprK is a possible porin transporter of T. pallidum, a biological function compatible with its structural models. These results bring us closer to a comprehensive understanding of the function of this important virulence factor in syphilis pathogenesis and T. pallidum biology.
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Affiliation(s)
- Tingting Lian
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing 210042, China.
| | - Bing Zhang
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai 200120, China.
| | - Lorenzo Giacani
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, WA, USA; Department of Global Health, University of Washington, Seattle, WA, USA.
| | - Caixia Kou
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing 210042, China.
| | - Xiuna Yang
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai 200120, China.
| | - Ruili Zhang
- Department of Dermatology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing 210042, China.
| | - Qianqiu Wang
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing 210042, China.
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14
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Lin MJ, Haynes AM, Addetia A, Lieberman NAP, Phung Q, Xie H, Nguyen TV, Molini BJ, Lukehart SA, Giacani L, Greninger AL. Longitudinal TprK profiling of in vivo and in vitro-propagated Treponema pallidum subsp. pallidum reveals accumulation of antigenic variants in absence of immune pressure. PLoS Negl Trop Dis 2021; 15:e0009753. [PMID: 34492041 PMCID: PMC8480903 DOI: 10.1371/journal.pntd.0009753] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/29/2021] [Accepted: 08/23/2021] [Indexed: 11/25/2022] Open
Abstract
Immune evasion by Treponema pallidum subspecies pallidum (T. pallidum) has been attributed to antigenic variation of its putative outer-membrane protein TprK. In TprK, amino acid diversity is confined to seven variable (V) regions, and generation of sequence diversity within the V regions occurs via a non-reciprocal segmental gene conversion mechanism where donor cassettes recombine into the tprK expression site. Although previous studies have shown the significant role of immune selection in driving accumulation of TprK variants, the contribution of baseline gene conversion activity to variant diversity is less clear. Here, combining longitudinal tprK deep sequencing of near clonal Chicago C from immunocompetent and immunosuppressed rabbits along with the newly developed in vitro cultivation system for T. pallidum, we directly characterized TprK alleles in the presence and absence of immune selection. Our data confirm significantly greater sequence diversity over time within the V6 region during syphilis infection in immunocompetent rabbits compared to immunosuppressed rabbits, consistent with previous studies on the role of TprK in evasion of the host immune response. Compared to strains grown in immunocompetent rabbits, strains passaged in vitro displayed low level changes in allele frequencies of TprK variable region sequences similar to that of strains passaged in immunosuppressed rabbits. Notably, we found significantly increased rates of V6 allele generation relative to other variable regions in in vitro cultivated T, pallidum strains, illustrating that the diversity within these hypervariable regions occurs in the complete absence of immune selection. Together, our results demonstrate antigenic variation in T. pallidum can be studied in vitro and occurs even in the complete absence of immune pressure, allowing the T. pallidum population to continuously evade the immune system of the infected host.
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Affiliation(s)
- Michelle J. Lin
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, United States of America
| | - Austin M. Haynes
- Pathobiology Graduate Program, University of Washington, Seattle, Washington, United States of America
| | - Amin Addetia
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, United States of America
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington, United States of America
| | - Nicole A. P. Lieberman
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, United States of America
| | - Quynh Phung
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, United States of America
| | - Hong Xie
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, United States of America
| | - Tien V. Nguyen
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, United States of America
| | - Barbara J. Molini
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, United States of America
| | - Sheila A. Lukehart
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Lorenzo Giacani
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, United States of America
| | - Alexander L. Greninger
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, United States of America
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- * E-mail:
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15
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Rawal K, Sinha R, Abbasi BA, Chaudhary A, Nath SK, Kumari P, Preeti P, Saraf D, Singh S, Mishra K, Gupta P, Mishra A, Sharma T, Gupta S, Singh P, Sood S, Subramani P, Dubey AK, Strych U, Hotez PJ, Bottazzi ME. Identification of vaccine targets in pathogens and design of a vaccine using computational approaches. Sci Rep 2021; 11:17626. [PMID: 34475453 PMCID: PMC8413327 DOI: 10.1038/s41598-021-96863-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 08/10/2021] [Indexed: 02/07/2023] Open
Abstract
Antigen identification is an important step in the vaccine development process. Computational approaches including deep learning systems can play an important role in the identification of vaccine targets using genomic and proteomic information. Here, we present a new computational system to discover and analyse novel vaccine targets leading to the design of a multi-epitope subunit vaccine candidate. The system incorporates reverse vaccinology and immuno-informatics tools to screen genomic and proteomic datasets of several pathogens such as Trypanosoma cruzi, Plasmodium falciparum, and Vibrio cholerae to identify potential vaccine candidates (PVC). Further, as a case study, we performed a detailed analysis of the genomic and proteomic dataset of T. cruzi (CL Brenner and Y strain) to shortlist eight proteins as possible vaccine antigen candidates using properties such as secretory/surface-exposed nature, low transmembrane helix (< 2), essentiality, virulence, antigenic, and non-homology with host/gut flora proteins. Subsequently, highly antigenic and immunogenic MHC class I, MHC class II and B cell epitopes were extracted from top-ranking vaccine targets. The designed vaccine construct containing 24 epitopes, 3 adjuvants, and 4 linkers was analysed for its physicochemical properties using different tools, including docking analysis. Immunological simulation studies suggested significant levels of T-helper, T-cytotoxic cells, and IgG1 will be elicited upon administration of such a putative multi-epitope vaccine construct. The vaccine construct is predicted to be soluble, stable, non-allergenic, non-toxic, and to offer cross-protection against related Trypanosoma species and strains. Further, studies are required to validate safety and immunogenicity of the vaccine.
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Affiliation(s)
- Kamal Rawal
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India.
| | - Robin Sinha
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Bilal Ahmed Abbasi
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Amit Chaudhary
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Swarsat Kaushik Nath
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Priya Kumari
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - P Preeti
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Devansh Saraf
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Shachee Singh
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Kartik Mishra
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Pranjay Gupta
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Astha Mishra
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Trapti Sharma
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Srijanee Gupta
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Prashant Singh
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Shriya Sood
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Preeti Subramani
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Aman Kumar Dubey
- Centre for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | - Ulrich Strych
- Texas Children's Hospital Center for Vaccine Development, Departments of Pediatrics and Molecular Virology and Microbiology, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Peter J Hotez
- Texas Children's Hospital Center for Vaccine Development, Departments of Pediatrics and Molecular Virology and Microbiology, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
- Department of Biology, Baylor University, Waco, TX, USA
| | - Maria Elena Bottazzi
- Texas Children's Hospital Center for Vaccine Development, Departments of Pediatrics and Molecular Virology and Microbiology, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
- Department of Biology, Baylor University, Waco, TX, USA
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16
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Plotnikoff KM, Donken R, Smith L, Cameron C, LaMontagne DS, Bettinger JA, Sadarangani M, Grennan T, Racey CS, Hybiske K, Naus M, Monteiro A, Ogilvie GS. Priorities for sexually transmitted infection vaccine research and development: Results from a survey of global leaders and representatives. Vaccine X 2021; 8:100107. [PMID: 34401741 PMCID: PMC8356130 DOI: 10.1016/j.jvacx.2021.100107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 06/04/2021] [Accepted: 06/24/2021] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE To determine the sexually transmitted infection (STI) vaccine research priorities of global leaders in STI vaccine research, development, and service provision. METHODS Global representatives attending the STI Vaccines: Opportunities for Research, Development, and Implementation symposium preceding the STI & HIV World Congress in 2019 were invited to complete an electronic survey. We asked participants to rank items by importance/priority for STI vaccine development for the following areas of focus: specific STIs (gonorrhea, chlamydia, syphilis, herpes, and trichomoniasis), broad research domains (basic science, funding, communication, program planning, and vaccine hesitancy), and specific research activities related to these domains. We calculated weighted value scores based on the ranking (e.g., first, second, third) and the total number of responses in order to produce a ranked list of the priorities. RESULTS A total of 46 out of 97 (44%) symposium attendees responded to the survey. Gonorrhea was identified as the STI that should be prioritized for vaccine development, followed by syphilis with weighted value scores of 3.82 and 3.37, respectively, out of a maximum of five. Basic science (and vaccine development) was the domain ranked with the highest priority with a weighted value score of 4.78 out of six. Research activities related to basic science and vaccine development (including pre-clinical and clinical trials, and surveillance measures) and increased funding opportunities were the most highly ranked activities in the "STI vaccine development" and "research domains and activities" categories. CONCLUSION Global leaders in attendance at the STI Vaccines symposium prioritized continued scientific work in vaccine development and program planning. Gonorrhea was identified as the highest priority infection, followed by syphilis.
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Affiliation(s)
- Kara M. Plotnikoff
- School of Population and Public Health, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- Women’s Health Research Institute, British Columbia Women’s Hospital and Health Centre, Vancouver, BC, Canada
| | - Robine Donken
- School of Population and Public Health, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- Women’s Health Research Institute, British Columbia Women’s Hospital and Health Centre, Vancouver, BC, Canada
- Vaccine Evaluation Center, BC Children’s Hospital Research Institute, Vancouver, BC, Canada
| | - Laurie Smith
- Women’s Health Research Institute, British Columbia Women’s Hospital and Health Centre, Vancouver, BC, Canada
- Cancer Control Research, BC Cancer, Vancouver, BC, Canada
| | - Caroline Cameron
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA
| | - D. Scott LaMontagne
- PATH, Center for Vaccine Innovation & Access, Seattle, WA, USA
- Department of Global Health, University of Washington, Seattle, WA, USA
| | - Julie A. Bettinger
- Women’s Health Research Institute, British Columbia Women’s Hospital and Health Centre, Vancouver, BC, Canada
- Vaccine Evaluation Center, BC Children’s Hospital Research Institute, Vancouver, BC, Canada
| | - Manish Sadarangani
- Vaccine Evaluation Center, BC Children’s Hospital Research Institute, Vancouver, BC, Canada
- Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada
| | - Troy Grennan
- Division of Infectious Diseases, University of British Columbia, Vancouver, BC, Canada
- British Columbia Centre for Disease Control, Vancouver, BC, Canada
| | - C. Sarai Racey
- School of Population and Public Health, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- Women’s Health Research Institute, British Columbia Women’s Hospital and Health Centre, Vancouver, BC, Canada
| | - Kevin Hybiske
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA
- Department of Global Health, University of Washington, Seattle, WA, USA
| | - Monika Naus
- School of Population and Public Health, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- British Columbia Centre for Disease Control, Vancouver, BC, Canada
| | - Amanda Monteiro
- Women’s Health Research Institute, British Columbia Women’s Hospital and Health Centre, Vancouver, BC, Canada
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - Gina S. Ogilvie
- School of Population and Public Health, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- Women’s Health Research Institute, British Columbia Women’s Hospital and Health Centre, Vancouver, BC, Canada
- British Columbia Centre for Disease Control, Vancouver, BC, Canada
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17
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Hawley KL, Montezuma-Rusca JM, Delgado KN, Singh N, Uversky VN, Caimano MJ, Radolf JD, Luthra A. Structural Modeling of the Treponema pallidum Outer Membrane Protein Repertoire: a Road Map for Deconvolution of Syphilis Pathogenesis and Development of a Syphilis Vaccine. J Bacteriol 2021; 203:e0008221. [PMID: 33972353 PMCID: PMC8407342 DOI: 10.1128/jb.00082-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/27/2021] [Indexed: 01/11/2023] Open
Abstract
Treponema pallidum, an obligate human pathogen, has an outer membrane (OM) whose physical properties, ultrastructure, and composition differ markedly from those of phylogenetically distant Gram-negative bacteria. We developed structural models for the outer membrane protein (OMP) repertoire (OMPeome) of T. pallidum Nichols using solved Gram-negative structures, computational tools, and small-angle X-ray scattering (SAXS) of selected recombinant periplasmic domains. The T. pallidum "OMPeome" harbors two "stand-alone" proteins (BamA and LptD) involved in OM biogenesis and four paralogous families involved in the influx/efflux of small molecules: 8-stranded β-barrels, long-chain-fatty-acid transporters (FadLs), OM factors (OMFs) for efflux pumps, and T. pallidum repeat proteins (Tprs). BamA (TP0326), the central component of a β-barrel assembly machine (BAM)/translocation and assembly module (TAM) hybrid, possesses a highly flexible polypeptide-transport-associated (POTRA) 1-5 arm predicted to interact with TamB (TP0325). TP0515, an LptD ortholog, contains a novel, unstructured C-terminal domain that models inside the β-barrel. T. pallidum has four 8-stranded β-barrels, each containing positively charged extracellular loops that could contribute to pathogenesis. Three of five FadL-like orthologs have a novel α-helical, presumptively periplasmic C-terminal extension. SAXS and structural modeling further supported the bipartite membrane topology and tridomain architecture of full-length members of the Tpr family. T. pallidum's two efflux pumps presumably extrude noxious small molecules via four coexpressed OMFs with variably charged tunnels. For BamA, LptD, and OMFs, we modeled the molecular machines that deliver their substrates into the OM or external milieu. The spirochete's extended families of OM transporters collectively confer a broad capacity for nutrient uptake. The models also furnish a structural road map for vaccine development. IMPORTANCE The unusual outer membrane (OM) of T. pallidum, the syphilis spirochete, is the ultrastructural basis for its well-recognized capacity for invasiveness, immune evasion, and persistence. In recent years, we have made considerable progress in identifying T. pallidum's repertoire of OMPs. Here, we developed three-dimensional (3D) models for the T. pallidum Nichols OMPeome using structural modeling, bioinformatics, and solution scattering. The OM contains three families of OMP transporters, an OMP family involved in the extrusion of noxious molecules, and two "stand-alone" proteins involved in OM biogenesis. This work represents a major advance toward elucidating host-pathogen interactions during syphilis; understanding how T. pallidum, an extreme auxotroph, obtains a wide array of biomolecules from its obligate human host; and developing a vaccine with global efficacy.
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Affiliation(s)
- Kelly L. Hawley
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Division of Infectious Diseases and Immunology, Connecticut Children’s, Hartford, Connecticut, USA
| | - Jairo M. Montezuma-Rusca
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Division of Infectious Diseases, UConn Health, Farmington, Connecticut, USA
| | | | - Navreeta Singh
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
| | - Vladimir N. Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Melissa J. Caimano
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Justin D. Radolf
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
- Department of Genetics and Genome Sciences, UConn Health, Farmington, Connecticut, USA
- Department of Immunology, UConn Health, Farmington, Connecticut, USA
| | - Amit Luthra
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
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Addetia A, Tantalo LC, Lin MJ, Xie H, Huang ML, Marra CM, Greninger AL. Comparative genomics and full-length Tprk profiling of Treponema pallidum subsp. pallidum reinfection. PLoS Negl Trop Dis 2020; 14:e0007921. [PMID: 32251462 PMCID: PMC7162541 DOI: 10.1371/journal.pntd.0007921] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 04/16/2020] [Accepted: 02/08/2020] [Indexed: 12/25/2022] Open
Abstract
Developing a vaccine against Treponema pallidum subspecies pallidum, the causative agent of syphilis, remains a public health priority. Syphilis vaccine design efforts have been complicated by lack of an in vitro T. pallidum culture system, prolific antigenic variation in outer membrane protein TprK, and lack of functional annotation for nearly half of the genes. Understanding the genetic basis of T. pallidum reinfection can provide insights into variation among strains that escape cross-protective immunity. Here, we present comparative genomic sequencing and deep, full-length tprK profiling of two T. pallidum isolates from blood from the same patient that were collected six years apart. Notably, this patient was diagnosed with syphilis four times, with two of these episodes meeting the definition of neurosyphilis, during this interval. Outside of the highly variable tprK gene, we identified 14 coding changes in 13 genes. Nine of these genes putatively localized to the periplasmic or outer membrane spaces, consistent with a potential role in serological immunoevasion. Using a newly developed full-length tprK deep sequencing protocol, we profiled the diversity of this gene that far outpaces the rest of the genome. Intriguingly, we found that the reinfecting isolate demonstrated less diversity across each tprK variable region compared to the isolate from the first infection. Notably, the two isolates did not share any full-length TprK sequences. Our results are consistent with an immunodominant-evasion model in which the diversity of TprK explains the ability of T. pallidum to successfully reinfect individuals, even when they have been infected with the organism multiple times.
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Affiliation(s)
- Amin Addetia
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
| | - Lauren C. Tantalo
- Department of Neurology, University of Washington, Seattle, Washington, United States of America
| | - Michelle J. Lin
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
| | - Hong Xie
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
| | - Meei-Li Huang
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
| | - Christina M. Marra
- Department of Neurology, University of Washington, Seattle, Washington, United States of America
| | - Alexander L. Greninger
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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Mikalová L, Janečková K, Nováková M, Strouhal M, Čejková D, Harper KN, Šmajs D. Whole genome sequence of the Treponema pallidum subsp. endemicum strain Iraq B: A subpopulation of bejel treponemes contains full-length tprF and tprG genes similar to those present in T. p. subsp. pertenue strains. PLoS One 2020; 15:e0230926. [PMID: 32236138 PMCID: PMC7112178 DOI: 10.1371/journal.pone.0230926] [Citation(s) in RCA: 4] [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: 11/28/2019] [Accepted: 03/11/2020] [Indexed: 11/25/2022] Open
Abstract
Treponema pallidum subsp. endemicum (TEN) is the causative agent of endemic syphilis (bejel). Until now, only a single TEN strain, Bosnia A, has been completely sequenced. The only other laboratory TEN strain available, Iraq B, was isolated in Iraq in 1951 by researchers from the US Centers for Disease Control and Prevention. In this study, the complete genome of the Iraq B strain was amplified as overlapping PCR products and sequenced using the pooled segment genome sequencing method and Illumina sequencing. Total average genome sequencing coverage reached 3469×, with a total genome size of 1,137,653 bp. Compared to the genome sequence of Bosnia A, a set of 37 single nucleotide differences, 4 indels, 2 differences in the number of tandem repetitions, and 18 differences in the length of homopolymeric regions were found in the Iraq B genome. Moreover, the tprF and tprG genes that were previously found deleted in the genome of the TEN Bosnia A strain (spanning 2.3 kb in length) were present in a subpopulation of TEN Iraq B and Bosnia A microbes, and their sequence was highly similar to those found in T. p. subsp. pertenue strains, which cause the disease yaws. The genome sequence of TEN Iraq B revealed close genetic relatedness between both available bejel-causing laboratory strains (i.e., Iraq B and Bosnia A) and also genetic variability within the bejel treponemes comparable to that found within yaws- or syphilis-causing strains. In addition, genetic relatedness to TPE strains was demonstrated by the sequence of the tprF and tprG genes found in subpopulations of both TEN Iraq B and Bosnia A. The loss of the tprF and tprG genes in most TEN microbes suggest that TEN genomes have been evolving via the loss of genomic regions, a phenomenon previously found among the treponemes causing both syphilis and rabbit syphilis.
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Affiliation(s)
- Lenka Mikalová
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Klára Janečková
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Markéta Nováková
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Michal Strouhal
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Darina Čejková
- Department of Immunology, Veterinary Research Institute, Brno, Czech Republic
| | - Kristin N. Harper
- Department of Population Biology, Ecology, and Evolution, Emory University, Atlanta, Georgia, United States of America
| | - David Šmajs
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
- * E-mail:
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20
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Li QL, Tong ML, Liu LL, Lin LR, Lin Y, Yang TC. Effect of anti-TP0136 antibodies on the progression of lesions in an infected rabbit model. Int Immunopharmacol 2020; 83:106428. [PMID: 32217461 DOI: 10.1016/j.intimp.2020.106428] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/17/2020] [Accepted: 03/18/2020] [Indexed: 11/17/2022]
Abstract
The effect of anti-TP0136 antibodies on the progression of syphilis is poorly understood. This study aimed to investigate the effect of anti-TP0136 antibodies on the progression of lesions in an infected rabbit model. Intramuscular injection of rTP0136 into rabbits in the immunized group (n = 4) elicited high titers of anti-TP0136 antibodies, and rabbits were then challenged with 105T. pallidum per site along their back. Lesion development was observed, and the injection sites were biopsied for tp0574 mRNA and histological analyses every week until the wound healed. The rabbits in the control group were injected with normal saline instead of rTP0136. Viable T. pallidum in the challenged rabbits was assessed with rabbit infectivity tests. The lesions in the immunized group took longer to heal than those in the control group (42 d vs. 28 d, P < 0.001) and had markedly higher levels of total cellular infiltrates. The mRNA level of tp0574 in the immunized group was significantly higher than that in the control group (P < 0.05). Viable T. pallidum was detected in rabbit lymph nodes in both the immunized and control groups. Our study showed that high titers of anti-TP0136 antibodies promoted the infiltration of inflammatory cells into local lesions and intensified tissue damage, thus delaying wound healing, and had no protective effect on the occurrence of syphilis in the rabbit model.
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Affiliation(s)
- Qiu-Ling Li
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China; Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Man-Li Tong
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China; Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Li-Li Liu
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Li-Rong Lin
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Yu Lin
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China.
| | - Tian-Ci Yang
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China; Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China.
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21
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Jaiswal AK, Tiwari S, Jamal SB, de Castro Oliveira L, Alves LG, Azevedo V, Ghosh P, Oliveira CJF, Soares SC. The pan-genome of Treponema pallidum reveals differences in genome plasticity between subspecies related to venereal and non-venereal syphilis. BMC Genomics 2020; 21:33. [PMID: 31924165 PMCID: PMC6953169 DOI: 10.1186/s12864-019-6430-6] [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] [Received: 10/10/2019] [Accepted: 12/24/2019] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Spirochetal organisms of the Treponema genus are responsible for causing Treponematoses. Pathogenic treponemes is a Gram-negative, motile, spirochete pathogen that causes syphilis in human. Treponema pallidum subsp. endemicum (TEN) causes endemic syphilis (bejel); T. pallidum subsp. pallidum (TPA) causes venereal syphilis; T. pallidum subsp. pertenue (TPE) causes yaws; and T. pallidum subsp. Ccarateum causes pinta. Out of these four high morbidity diseases, venereal syphilis is mediated by sexual contact; the other three diseases are transmitted by close personal contact. The global distribution of syphilis is alarming and there is an increasing need of proper treatment and preventive measures. Unfortunately, effective measures are limited. RESULTS Here, the genome sequences of 53 T. pallidum strains isolated from different parts of the world and a diverse range of hosts were comparatively analysed using pan-genomic strategy. Phylogenomic, pan-genomic, core genomic and singleton analysis disclosed the close connection among all strains of the pathogen T. pallidum, its clonal behaviour and showed increases in the sizes of the pan-genome. Based on the genome plasticity analysis of the subsets containing the subspecies T pallidum subsp. pallidum, T. pallidum subsp. endemicum and T. pallidum subsp. pertenue, we found differences in the presence/absence of pathogenicity islands (PAIs) and genomic islands (GIs) on subsp.-based study. CONCLUSIONS In summary, we identified four pathogenicity islands (PAIs), eight genomic islands (GIs) in subsp. pallidum, whereas subsp. endemicum has three PAIs and seven GIs and subsp. pertenue harbours three PAIs and eight GIs. Concerning the presence of genes in PAIs and GIs, we found some genes related to lipid and amino acid biosynthesis that were only present in the subsp. of T. pallidum, compared to T. pallidum subsp. endemicum and T. pallidum subsp. pertenue.
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Affiliation(s)
- Arun Kumar Jaiswal
- PG Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.,Department of Immunology, Microbiology and Parasitology, Institute of Biological Sciences and Natural Sciences, Federal University of Triângulo Mineiro (UFTM), Uberaba, MG, Brazil
| | - Sandeep Tiwari
- PG Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
| | - Syed Babar Jamal
- Department of Biological Sciences, National University of Medical Sciences, Abid Majeed Road, Rawalpindi, Punjab, 46000, Pakistan
| | - Letícia de Castro Oliveira
- PG Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.,Department of Immunology, Microbiology and Parasitology, Institute of Biological Sciences and Natural Sciences, Federal University of Triângulo Mineiro (UFTM), Uberaba, MG, Brazil
| | - Leandro Gomes Alves
- Department of Immunology, Microbiology and Parasitology, Institute of Biological Sciences and Natural Sciences, Federal University of Triângulo Mineiro (UFTM), Uberaba, MG, Brazil
| | - Vasco Azevedo
- PG Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Preetam Ghosh
- Department of Computer Science, Virginia Commonwealth University, Richmond, VA-23284, USA
| | - Carlo Jose Freira Oliveira
- Department of Immunology, Microbiology and Parasitology, Institute of Biological Sciences and Natural Sciences, Federal University of Triângulo Mineiro (UFTM), Uberaba, MG, Brazil
| | - Siomar C Soares
- Department of Immunology, Microbiology and Parasitology, Institute of Biological Sciences and Natural Sciences, Federal University of Triângulo Mineiro (UFTM), Uberaba, MG, Brazil.
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22
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Marchese V, Dal Zoppo S, Quaresima V, Rossi B, Matteelli A. Vaccines for STIs: Present and Future Directions. Sex Transm Infect 2020. [DOI: 10.1007/978-3-030-02200-6_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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23
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Fernandez MC, Giacani L. Molecular and Immunological Strategies Against Treponema pallidum Infections. Sex Transm Infect 2020. [DOI: 10.1007/978-3-030-02200-6_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Bandara HMHN, Samaranayake LP. Viral, bacterial, and fungal infections of the oral mucosa: Types, incidence, predisposing factors, diagnostic algorithms, and management. Periodontol 2000 2019; 80:148-176. [PMID: 31090135 DOI: 10.1111/prd.12273] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
For millions of years, microbiota residing within us, including those in the oral cavity, coexisted in a harmonious symbiotic fashion that provided a quintessential foundation for human health. It is now clear that disruption of such a healthy relationship leading to microbial dysbiosis causes a wide array of infections, ranging from localized, mild, superficial infections to deep, disseminated life-threatening diseases. With recent advances in research, diagnostics, and improved surveillance we are witnessing an array of emerging and re-emerging oral infections and orofacial manifestations of systemic infections. Orofacial infections may cause significant discomfort to the patients and unnecessary economic burden. Thus, the early recognition of such infections is paramount for holistic patient management, and oral clinicians have a critical role in recognizing, diagnosing, managing, and preventing either new or old orofacial infections. This paper aims to provide an update on current understanding of well-established and emerging viral, bacterial, and fungal infections manifesting in the human oral cavity.
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Affiliation(s)
| | - Lakshman P Samaranayake
- Department of Oral and Craniofacial Health Sciences, College of Dental Medicine, University of Sharjah, Sharjah, UAE
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25
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Liu Y, Bian QQ, Zhang SH, Wang J, Wang ZM, Li JY. Post-treatment serological changes in some patients with early syphilis exhibit a parabolic trend. Int J STD AIDS 2019; 30:1389-1396. [PMID: 31744395 DOI: 10.1177/0956462419871855] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Early syphilis accounts for a large proportion of patients with syphilis. Non- Treponema pallidum tests are commonly used to assess treatment effectiveness by analyzing the serological titer before treatment and six months after treatment. However, serological changes during the first three months after completion of treatment have not been completely understood. This prompted us to investigate whether serum titers of patients exhibit a continuous decrease post-treatment and to assess the trend of change in serological titer during this period. One hundred and seventy-three eligible patients with early syphilis were included in the analysis. Pre-treatment serological titers and those at three and six months post-treatment were compared and analyzed. Serological recovery was defined as a 4-fold or greater decrease in titer from pre-treatment level. Forty patients (23.1%) were found to have an increased serum titer at three months after treatment. Among the 40 patients, 13 patients had primary syphilis, 5 patients had secondary syphilis, and 22 patients had early latent syphilis. The proportion of patients with primary syphilis was higher, and their initial titers were significantly lower. No significant differences were observed with respect to age, gender, or initial treatment. The assessment results of 17 patients (9.8% of the total patients) change. Serological changes in some patients exhibit a parabolic pattern that may affect the clinician’s assessment of patient recovery. Therefore, more frequent assessment of serological titer might be required within the first six months post-treatment.
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Affiliation(s)
- Yong Liu
- Department of Dermatology and STD, The Third Central Hospital of Tianjin; Tianjin Key Laboratory of Artificial Cell; Artificial Cell Engineering Technology Research Center of Public Health Ministry, Tianjin, China
| | - Que-Qiao Bian
- Department of Dermatology and STD, The Third Central Hospital of Tianjin; Tianjin Key Laboratory of Artificial Cell; Artificial Cell Engineering Technology Research Center of Public Health Ministry, Tianjin, China
| | - Shu-Huan Zhang
- Department of Dermatology and STD, The Third Central Hospital of Tianjin; Tianjin Key Laboratory of Artificial Cell; Artificial Cell Engineering Technology Research Center of Public Health Ministry, Tianjin, China
| | - Jun Wang
- Department of Dermatology and STD, The Third Central Hospital of Tianjin; Tianjin Key Laboratory of Artificial Cell; Artificial Cell Engineering Technology Research Center of Public Health Ministry, Tianjin, China
| | - Zhen-Ming Wang
- Department of Clinical Laboratory, The Third Central Hospital of Tianjin, Tianjin, China
| | - Jun-Yue Li
- Department of Clinical Laboratory, The Third Central Hospital of Tianjin, Tianjin, China
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Evaluation of the Protective Ability of the Treponema pallidum subsp. pallidum Tp0126 OmpW Homolog in the Rabbit Model of Syphilis. Infect Immun 2019; 87:IAI.00323-19. [PMID: 31182617 DOI: 10.1128/iai.00323-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 05/30/2019] [Indexed: 12/16/2022] Open
Abstract
In silico analyses of Treponema pallidum subsp. pallidum genomes and predicted proteomes to search for homologs of known bacterial outer membrane proteins (OMPs) led to the identification of tp0126 as a gene encoding a putative member of the OmpW family of porins/virulence factors. Our previous investigations on the role of Tp0126 in T. pallidum biology and syphilis pathogenesis showed that Tp0126 is fully conserved among T. pallidum strains and that transcription of tp0126 is driven by σ70 These initial results pointed to a housekeeping function for this protein. We also demonstrated that a guanosine homopolymer of various lengths located between the -10 and -35 consensus sequences in the tp0126 promoter modulates transcription consistently with phase variation, a mechanism that we also previously described for other T. pallidum genes encoding putative OMPs/virulence factors and that is often employed as a strategy for immune evasion. Circular dichroism spectra of recombinant Tp0126 also supported its structural homology with OmpW. Here we further investigated the humoral and cellular responses to Tp0126 during experimental and natural syphilis and the ability of Tp0126 to confer protection against syphilis in immunized rabbits. B-cell epitope mapping showed that compared to sera from experimentally infected animals, immunizations enhanced humoral immunity to sequences located in the putative Tp0126 surface-exposed loops, while phagocytosis assays showed that postimmunization sera opsonized T. pallidum Despite such promising results, no significant protection was seen following infectious challenge in immunized animals versus controls. Functional redundancy and phase variation might explain the lack of effectiveness of this vaccine candidate and/or design.
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27
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Liu D, Tong ML, Lin Y, Liu LL, Lin LR, Yang TC. Insights into the genetic variation profile of tprK in Treponema pallidum during the development of natural human syphilis infection. PLoS Negl Trop Dis 2019; 13:e0007621. [PMID: 31329597 PMCID: PMC6675121 DOI: 10.1371/journal.pntd.0007621] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 08/01/2019] [Accepted: 07/09/2019] [Indexed: 01/25/2023] Open
Abstract
Background Although the tprK gene of Treponema pallidum are thought to play a critical role in the pathogenesis of syphilis, the profile of variations in tprK during the development of human syphilis infection have remained unclear. Methods/Principal findings Through next-generation sequencing, we compared the tprK gene of 14 secondary syphilis patients with that of 14 primary syphilis patients, and the results showed an increased number of variants within the seven V regions of the tprK gene in the secondary syphilis samples. The length of the sequences within each V region also presented a 3-bp changing pattern. Interestingly, the frequencies of predominant sequences within the V regions in the secondary syphilis samples were generally decreased compared with those found in the primary syphilis samples, particularly in the V7 region, where a frequency below 60% was found in up to 57% (8/14) of all secondary samples compared with 7% (1/14) of all primary samples. Moreover, the number of minor variants distributed between frequencies of 10 and 49.9% was increased. The alignment of all amino acid sequences within each V region of the primary and secondary syphilis samples revealed that some amino acid sequences, particularly the amino acid sequences IASDGGAIKH and IASEDGSAGNLKH in V1, were highly stable. Additionally, the amino acid sequences in V6 also exhibited notable intrastrain heterogeneity and were likely to form a strain-specific pattern at the interstrain level. Conclusions The identification of different profiles of the tprK gene in primary and secondary syphilis patients indicated that the tprK gene of T. pallidum undergoes constant variation to result in the best adaptation to the host. The highly stable peptides found in V1 are likely promising potential vaccine components. The highly heterogenetic regions (e.g., V6) could help to understand the role of tprK in immune evasion. Antigenic variation of the TprK antigen has been acknowledged to explain the persistence of Treponema pallidum in the host, however, the profile of variations in tprK during the development of human syphilis infection has not been well characterized. Here, we performed next-generation sequencing to compare the variations in tprK between primary and secondary syphilis samples. The profiles of tprK in the samples at different stages showed differences. A higher amount of pool variants within seven V regions was found in the secondary syphilis samples, and the frequencies of their predominant sequences generally decreased with increases in the number of minor variants with frequencies in the range of 10 to 49.9%. However, the length of variable sequences within the V regions of tprK in the secondary syphilis samples also presented a 3-bp changing pattern. Notably, the amino acid sequences IASDGGAIKH and IASEDGSAGNLKH in V1 not only presented a high proportion of interstrain sharing but also were found at a relatively high frequency (above 80%) in the populations. The sequences in V6 of the samples demonstrated substantial variability at the intra- and interstrain levels. These findings could provide insights into the potential syphilis vaccine components and the role of TprK in immune evasion.
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Affiliation(s)
- Dan Liu
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Man-Li Tong
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Yong Lin
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Li-Li Liu
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Li-Rong Lin
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Tian-Ci Yang
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
- * E-mail:
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Abstract
The outer membrane (OM) of Treponema pallidum, the uncultivatable agent of venereal syphilis, has long been the subject of misconceptions and controversy. Decades ago, researchers postulated that T. pallidum's poor surface antigenicity is the basis for its ability to cause persistent infection, but they mistakenly attributed this enigmatic property to the presence of a protective outer coat of serum proteins and mucopolysaccharides. Subsequent studies revealed that the OM is the barrier to antibody binding, that it contains a paucity of integral membrane proteins, and that the preponderance of the spirochete's immunogenic lipoproteins is periplasmic. Since the advent of recombinant DNA technology, the fragility of the OM, its low protein content, and the lack of sequence relatedness between T. pallidum and Gram-negative outer membrane proteins (OMPs) have complicated efforts to characterize molecules residing at the host-pathogen interface. We have overcome these hurdles using the genomic sequence in concert with computational tools to identify proteins predicted to form β-barrels, the hallmark conformation of OMPs in double-membrane organisms and evolutionarily related eukaryotic organelles. We also have employed diverse methodologies to confirm that some candidate OMPs do, in fact, form amphiphilic β-barrels and are surface-exposed in T. pallidum. These studies have led to a structural homology model for BamA and established the bipartite topology of the T. pallidum repeat (Tpr) family of proteins. Recent bioinformatics has identified several structural orthologs for well-characterized Gram-negative OMPs, suggesting that the T. pallidum OMP repertoire is more Gram-negative-like than previously supposed. Lipoprotein adhesins and proteases on the spirochete surface also may contribute to disease pathogenesis and protective immunity.
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Affiliation(s)
- Justin D Radolf
- Departments of Medicine, Pediatrics, Molecular Biology and Biophysics, Genetics and Genomic Sciences, and Immunology, UConn Health, Farmington, CT 06030-3715, USA.
| | - Sanjiv Kumar
- Department of Medicine, UConn Health, Farmington, CT 06030-3715, USA
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Liu D, Tong ML, Luo X, Liu LL, Lin LR, Zhang HL, Lin Y, Niu JJ, Yang TC. Profile of the tprK gene in primary syphilis patients based on next-generation sequencing. PLoS Negl Trop Dis 2019; 13:e0006855. [PMID: 30789907 PMCID: PMC6400401 DOI: 10.1371/journal.pntd.0006855] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 03/05/2019] [Accepted: 12/07/2018] [Indexed: 12/04/2022] Open
Abstract
Background The highly variable tprK gene of Treponema pallidum has been acknowledged to be one of the mechanisms that causes persistent infection. Previous studies have mainly focused on the heterogeneity in tprK in propagated strains using a clone-based Sanger approach. Few studies have investigated tprK directly from clinical samples using deep sequencing. Methods/Principal findings We conducted a comprehensive analysis of 14 primary syphilis clinical isolates of T. pallidum via next-generation sequencing to gain better insight into the profile of tprK in primary syphilis patients. Our results showed that there was a mixture of distinct sequences within each V region of tprK. Except for the predominant sequence for each V region as previously reported using the clone-based Sanger approach, there were many minor variants of all strains that were mainly observed at a frequency of 1–5%. Interestingly, the identified distinct sequences within the regions were variable in length and differed by only 3 bp or multiples of 3 bp. In addition, amino acid sequence consistency within each V region was found among the 14 strains. Among the regions, the sequence IASDGGAIKH in V1 and the sequence DVGHKKENAANVNGTVGA in V4 showed a high stability of inter-strain redundancy. Conclusions The seven V regions of the tprK gene in primary syphilis infection demonstrated high diversity; they generally contained a high proportion sequence and numerous low-frequency minor variants, most of which are far below the detection limit of Sanger sequencing. The rampant variation in each V region was regulated by a strict gene conversion mechanism that maintained the length difference to 3 bp or multiples of 3 bp. The highly stable sequence of inter-strain redundancy may indicate that the sequences play a critical role in T. pallidum virulence. These highly stable peptides are also likely to be potential targets for vaccine development. Variations in tprK have been acknowledged to be the major contributors to persistent Treponema pallidum infections. Previous studies were based on the clone-based Sanger approach, and most of them were performed in propagated strains using rabbits, which could not reflect the actual heterogeneous characteristics of tprK in the context of human infection. In the present study, we employed next-generation sequencing (NGS) to explore the profile of tprK directly from 14 patients with primary syphilis. Our results showed a mixture of distinct sequences within each V region of tprK in these clinical samples. First, the length of identified distinct sequences within the region was variable, which differed by only 3 bp or multiples of 3 bp. Then, among the mixtures, a predominant sequence was usually observed for each V region, and the remaining minor variants were mainly observed at a frequency of 1–5%. In addition, there was a scenario of amino acid sequence consistency within the regions among the 14 primary syphilis strains. The identification of the profile of tprK in the context of human primary syphilis infection contributes to further exploration of the pathogenesis of syphilis.
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Affiliation(s)
- Dan Liu
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Man-Li Tong
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Xi Luo
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Li-Li Liu
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Li-Rong Lin
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Hui-Lin Zhang
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Yong Lin
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Jian-Jun Niu
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Zhongshan Hospital, Fujian Medical University, Xiamen, China
| | - Tian-Ci Yang
- Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, China
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
- * E-mail:
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Parveen N, Fernandez MC, Haynes AM, Zhang RL, Godornes BC, Centurion-Lara A, Giacani L. Non-pathogenic Borrelia burgdorferi expressing Treponema pallidum TprK and Tp0435 antigens as a novel approach to evaluate syphilis vaccine candidates. Vaccine 2019; 37:1807-1818. [PMID: 30797635 DOI: 10.1016/j.vaccine.2019.02.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/16/2019] [Accepted: 02/04/2019] [Indexed: 01/02/2023]
Abstract
BACKGROUND Syphilis is resurgent in many developed countries and still prevalent in developing nations. Current and future control campaigns would benefit from the development of a vaccine, but although promising vaccine candidates were identified among the putative surface-exposed integral outer membrane proteins of the syphilis spirochete, immunization experiments in the rabbit model using recombinant antigens have failed to fully protect animals upon infectious challenge. We speculated that such recombinant immunogens, purified under denaturing conditions from Escherichia coli prior to immunization might not necessarily harbor their original structure, and hypothesized that enhanced protection would result from performing similar immunization/challenge experiments with native antigens. METHODS To test our hypothesis, we engineered non-infectious Borrelia burgdorferi strains to express the tp0897 (tprK) and tp0435 genes of Treponema pallidum subsp. pallidum and immunized two groups of rabbits by injecting recombinant strains intramuscularly with no adjuvant. TprK is a putative integral outer membrane protein of the syphilis agent, while tp0435 encodes the highly immunogenic T. pallidum 17-kDa lipoprotein, a periplasmic antigen that was also shown on the pathogen surface. Following development of a specific host immune response to these antigens as the result of immunization, animals were challenged by intradermal inoculation of T. pallidum. Cutaneous lesion development was monitored and treponemal burden within lesions were assessed by dark-field microscopy and RT-qPCR, in comparison to control rabbits. RESULTS Partial protection was observed in rabbits immunized with B. burgdorferi expressing TprK while immunity to Tp0435 was not protective. Analysis of the humoral response to TprK antigen suggested reactivity to conformational epitopes. CONCLUSIONS Immunization with native antigens might not be sufficient to obtain complete protection to infection. Nonetheless we showed that non-infectious B. burgdorferi can be an effective carrier to deliver and elicit a specific host response to T. pallidum antigens to assess the efficacy of syphilis vaccine candidates.
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Affiliation(s)
- Nikhat Parveen
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers-New Jersey Medical School, Newark, NJ 07103, United States
| | - Mark C Fernandez
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Harborview Medical Center, Seattle, WA 98104, United States
| | - Austin M Haynes
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Harborview Medical Center, Seattle, WA 98104, United States
| | - Rui-Li Zhang
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Harborview Medical Center, Seattle, WA 98104, United States; Department of Dermatology, Affiliated Wuxi No.2 People's Hospital of Nanjing Medical University, 214002 Wuxi, China
| | - B Charmie Godornes
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Harborview Medical Center, Seattle, WA 98104, United States
| | | | - Lorenzo Giacani
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Harborview Medical Center, Seattle, WA 98104, United States; Department of Global Health, University of Washington, Seattle, WA 98104, United States.
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Navasa N, Fikrig E, Anguita J. Host Defenses to Spirochetes. Clin Immunol 2019. [DOI: 10.1016/b978-0-7020-6896-6.00028-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Immunotopological Analysis of the Treponema denticola Major Surface Protein (Msp). J Bacteriol 2018; 201:JB.00528-18. [PMID: 30373754 DOI: 10.1128/jb.00528-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 10/22/2018] [Indexed: 12/17/2022] Open
Abstract
Treponema denticola, one of several recognized periodontal pathogens, is a model organism for studying Treponema physiology and host-microbe interactions. Its major surface protein Msp (or MOSP) comprises an oligomeric outer membrane-associated complex that binds fibronectin, has cytotoxic pore-forming activity, and disrupts several intracellular responses. There are two hypotheses regarding native Msp structure and membrane topology. One hypothesis predicts that the entire Msp protein forms a β-barrel structure similar to that of well-studied outer membrane porins of Gram-negative bacteria. The second hypothesis predicts a bipartite Msp with distinct and separate periplasmic N-terminal and porin-like β-barrel C-terminal domains. The bipartite model, based on bioinformatic analysis of the orthologous Treponema pallidum Tpr proteins, is supported largely by studies of recombinant TprC and Msp polypeptides. The present study reports immunological studies in both T. denticola and Escherichia coli backgrounds to identify a prominent Msp surface epitope (residues 229 to 251 in ATCC 35405) in a domain that differs between strains with otherwise highly conserved Msps. These results were then used to evaluate a series of in silico structural models of representative T. denticola Msps. The data presented here are consistent with a model of Msp as a large-diameter β-barrel porin. This work adds to the knowledge regarding the diverse Msp-like proteins in oral treponemes and may contribute to an understanding of the evolutionary and potential functional relationships between Msps of oral Treponema and the orthologous group of Tpr proteins of T. pallidum. IMPORTANCE Treponema denticola is among a small subset of the oral microbiota contributing to severe periodontal disease. Due to its relative genetic tractability, T. denticola is a model organism for studying Treponema physiology and host-microbe interactions. T. denticola Msp is a highly expressed outer membrane-associated oligomeric protein that binds fibronectin, has cytotoxic pore-forming activity, and disrupts intracellular regulatory pathways. It shares homology with the orthologous group of T. pallidum Tpr proteins, one of which is implicated in T. pallidum in vivo antigenic variation. The outer membrane topologies of both Msp and the Tpr family proteins are unresolved, with conflicting reports on protein domain localization and function. In this study, we combined empirical immunological data derived both from diverse T. denticola strains and from recombinant Msp expression in E. coli with in silico predictive structural modeling of T. denticola Msp membrane topology, to move toward resolution of this important issue in Treponema biology.
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Immunogenicity and protective efficacy against Treponema pallidum in New Zealand rabbits immunized with plasmid DNA encoding flagellin. Emerg Microbes Infect 2018; 7:177. [PMID: 30405111 PMCID: PMC6220273 DOI: 10.1038/s41426-018-0176-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 09/10/2018] [Accepted: 09/13/2018] [Indexed: 11/08/2022]
Abstract
Plasmid DNA encoding flagellin FlaB3 was used as a vaccination candidate for the evaluation of immunogenicity and protection against Treponema pallidum subsp. pallidum dissemination. First, intramuscular injection of the flagellin encoded by the plasmid DNA into New Zealand rabbits elicited both humoral and cellular immune responses. Total IgG production increased in response to flagellin. In addition, serum IFN-γ secretion and CD8+ cells were substantially greater in the rabbits immunized with the plasmid encoding flagellin FlaB3 than those in the rabbits immunized with recombinant flagellin. The flagellin encoded by the plasmid DNA induced significant upregulation of serum IL-6 and IL-8 compared to that of the control rabbits. Subsequently, intradermal challenge of the vaccinated New Zealand rabbits with 1 × 107T. pallidum resulted in a significant reduction of the bacterial organ burden in the blood, liver, spleen, and testicles in the flagellin plasmid DNA-vaccinated rabbits. Furthermore, the histopathological analysis demonstrated that the rabbits immunized with the plasmid DNA-encoded flagellin (FlaB3) showed better immune protection. These findings provide evidence that plasmid DNA-encoded flagellin (FlaB3) may be useful as a potential immunization route for future development of a vaccine to inhibit T. pallidum dissemination in related animals.
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Lukehart SA. New Tools for Syphilis Research. mBio 2018; 9:e01417-18. [PMID: 30065094 PMCID: PMC6069119 DOI: 10.1128/mbio.01417-18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Syphilis research has been severely limited by the necessity to propagate Treponema pallidumin vivo in rabbits. After decades of erroneous or irreproducible reports of cultivation of T. pallidum, the recent very convincing report of its successful long-term in vitro propagation opens numerous opportunities for development of genetic tools for studying pathogenesis and protein function, antigenic variation, and surface exposure of antigens. The possibility of more rapid isolation of new strains will expand our knowledge of this organism beyond the century-old Nichols strain.
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Affiliation(s)
- Sheila A Lukehart
- Department of Medicine, University of Washington, Seattle, Washington, USA
- Department of Global Health, University of Washington, Seattle, Washington, USA
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Kumar S, Caimano MJ, Anand A, Dey A, Hawley KL, LeDoyt ME, La Vake CJ, Cruz AR, Ramirez LG, Paštěková L, Bezsonova I, Šmajs D, Salazar JC, Radolf JD. Sequence Variation of Rare Outer Membrane Protein β-Barrel Domains in Clinical Strains Provides Insights into the Evolution of Treponema pallidum subsp. pallidum, the Syphilis Spirochete. mBio 2018; 9:e01006-18. [PMID: 29895642 PMCID: PMC6016234 DOI: 10.1128/mbio.01006-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 05/10/2018] [Indexed: 02/07/2023] Open
Abstract
In recent years, considerable progress has been made in topologically and functionally characterizing integral outer membrane proteins (OMPs) of Treponema pallidum subspecies pallidum, the syphilis spirochete, and identifying its surface-exposed β-barrel domains. Extracellular loops in OMPs of Gram-negative bacteria are known to be highly variable. We examined the sequence diversity of β-barrel-encoding regions of tprC, tprD, and bamA in 31 specimens from Cali, Colombia; San Francisco, California; and the Czech Republic and compared them to allelic variants in the 41 reference genomes in the NCBI database. To establish a phylogenetic framework, we used T. pallidum 0548 (tp0548) genotyping and tp0558 sequences to assign strains to the Nichols or SS14 clades. We found that (i) β-barrels in clinical strains could be grouped according to allelic variants in T. pallidum subsp. pallidum reference genomes; (ii) for all three OMP loci, clinical strains within the Nichols or SS14 clades often harbored β-barrel variants that differed from the Nichols and SS14 reference strains; and (iii) OMP variable regions often reside in predicted extracellular loops containing B-cell epitopes. On the basis of structural models, nonconservative amino acid substitutions in predicted transmembrane β-strands of T. pallidum repeat C (TprC) and TprD2 could give rise to functional differences in their porin channels. OMP profiles of some clinical strains were mosaics of different reference strains and did not correlate with results from enhanced molecular typing. Our observations suggest that human host selection pressures drive T. pallidum subsp. pallidum OMP diversity and that genetic exchange contributes to the evolutionary biology of T. pallidum subsp. pallidum They also set the stage for topology-based analysis of antibody responses to OMPs and help frame strategies for syphilis vaccine development.IMPORTANCE Despite recent progress characterizing outer membrane proteins (OMPs) of Treponema pallidum, little is known about how their surface-exposed, β-barrel-forming domains vary among strains circulating within high-risk populations. In this study, sequences for the β-barrel-encoding regions of three OMP loci, tprC, tprD, and bamA, in T. pallidum subsp. pallidum isolates from a large number of patient specimens from geographically disparate sites were examined. Structural models predict that sequence variation within β-barrel domains occurs predominantly within predicted extracellular loops. Amino acid substitutions in predicted transmembrane strands that could potentially affect porin channel function were also noted. Our findings suggest that selection pressures exerted within human populations drive T. pallidum subsp. pallidum OMP diversity and that recombination at OMP loci contributes to the evolutionary biology of syphilis spirochetes. These results also set the stage for topology-based analysis of antibody responses that promote clearance of T. pallidum subsp. pallidum and frame strategies for vaccine development based upon conserved OMP extracellular loops.
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Affiliation(s)
- Sanjiv Kumar
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
| | - Melissa J Caimano
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Arvind Anand
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
| | - Abhishek Dey
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
| | - Kelly L Hawley
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Division of Pediatric Infectious Diseases, Connecticut Children's Medical Center, Hartford, Connecticut, USA
| | - Morgan E LeDoyt
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
| | - Carson J La Vake
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
| | - Adriana R Cruz
- Centro Internacional de Entrenamiento e Investigaciones Medicas (CIDEIM), Cali, Colombia
| | - Lady G Ramirez
- Centro Internacional de Entrenamiento e Investigaciones Medicas (CIDEIM), Cali, Colombia
| | - Lenka Paštěková
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Irina Bezsonova
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - David Šmajs
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Juan C Salazar
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Division of Pediatric Infectious Diseases, Connecticut Children's Medical Center, Hartford, Connecticut, USA
- Centro Internacional de Entrenamiento e Investigaciones Medicas (CIDEIM), Cali, Colombia
- Department of Immunology, UConn Health, Farmington, Connecticut, USA
| | - Justin D Radolf
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
- Department of Pediatrics, UConn Health, Farmington, Connecticut, USA
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
- Department of Immunology, UConn Health, Farmington, Connecticut, USA
- Department of Genetic and Genome Sciences, UConn Health, Farmington, Connecticut, USA
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Šmajs D, Strouhal M, Knauf S. Genetics of human and animal uncultivable treponemal pathogens. INFECTION GENETICS AND EVOLUTION 2018; 61:92-107. [PMID: 29578082 DOI: 10.1016/j.meegid.2018.03.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 03/16/2018] [Accepted: 03/20/2018] [Indexed: 10/17/2022]
Abstract
Treponema pallidum is an uncultivable bacterium and the causative agent of syphilis (subsp. pallidum [TPA]), human yaws (subsp. pertenue [TPE]), and bejel (subsp. endemicum). Several species of nonhuman primates in Africa are infected by treponemes genetically undistinguishable from known human TPE strains. Besides Treponema pallidum, the equally uncultivable Treponema carateum causes pinta in humans. In lagomorphs, Treponema paraluisleporidarum ecovar Cuniculus and ecovar Lepus are the causative agents of rabbit and hare syphilis, respectively. All uncultivable pathogenic treponemes harbor a relatively small chromosome (1.1334-1.1405 Mbp) and show gene synteny with minimal genetic differences (>98% identity at the DNA level) between subspecies and species. While uncultivable pathogenic treponemes contain a highly conserved core genome, there are a number of highly variable and/or recombinant chromosomal loci. This is also reflected in the occurrence of intrastrain heterogeneity (genetic diversity within an infecting bacterial population). Molecular differences at several different chromosomal loci identified among TPA strains or isolates have been used for molecular typing and the epidemiological characterization of syphilis isolates. This review summarizes genome structure of uncultivable pathogenic treponemes including genetically variable regions.
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Affiliation(s)
- David Šmajs
- Department of Biology, Masaryk University, Kamenice 5, Building A6, 625 00 Brno, Czech Republic.
| | - Michal Strouhal
- Department of Biology, Masaryk University, Kamenice 5, Building A6, 625 00 Brno, Czech Republic.
| | - Sascha Knauf
- Work Group Neglected Tropical Diseases, Pathology Unit, German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Göttingen, Germany,.
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Abstract
Treponema pallidum subspecies pallidum (T. pallidum) causes syphilis via sexual exposure or via vertical transmission during pregnancy. T. pallidum is renowned for its invasiveness and immune-evasiveness; its clinical manifestations result from local inflammatory responses to replicating spirochaetes and often imitate those of other diseases. The spirochaete has a long latent period during which individuals have no signs or symptoms but can remain infectious. Despite the availability of simple diagnostic tests and the effectiveness of treatment with a single dose of long-acting penicillin, syphilis is re-emerging as a global public health problem, particularly among men who have sex with men (MSM) in high-income and middle-income countries. Syphilis also causes several hundred thousand stillbirths and neonatal deaths every year in developing nations. Although several low-income countries have achieved WHO targets for the elimination of congenital syphilis, an alarming increase in the prevalence of syphilis in HIV-infected MSM serves as a strong reminder of the tenacity of T. pallidum as a pathogen. Strong advocacy and community involvement are needed to ensure that syphilis is given a high priority on the global health agenda. More investment is needed in research on the interaction between HIV and syphilis in MSM as well as into improved diagnostics, a better test of cure, intensified public health measures and, ultimately, a vaccine.
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Affiliation(s)
- Rosanna W Peeling
- London School of Hygiene &Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - David Mabey
- London School of Hygiene &Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Mary L Kamb
- Division of STD Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Xiang-Sheng Chen
- National Center for STD Control, Chinese Academy of Medical Sciences and Peking Union Medical College Institute of Dermatology, Nanjing, China
| | - Justin D Radolf
- Department of Medicine, UConn Health, Farmington, Connecticut, USA
| | - Adele S Benzaken
- Department of Surveillance, Prevention and Control of STI, HIV/AIDS and Viral Hepatitis, Ministry of Health, Brasília, Brazil
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A preliminary study on the proinflammatory mechanisms of Treponema pallidum outer membrane protein Tp92 in human macrophages and HMEC-1 cells. Microb Pathog 2017; 110:176-183. [DOI: 10.1016/j.micpath.2017.06.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 06/27/2017] [Accepted: 06/28/2017] [Indexed: 02/07/2023]
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Lithgow KV, Hof R, Wetherell C, Phillips D, Houston S, Cameron CE. A defined syphilis vaccine candidate inhibits dissemination of Treponema pallidum subspecies pallidum. Nat Commun 2017; 8:14273. [PMID: 28145405 PMCID: PMC5296639 DOI: 10.1038/ncomms14273] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 12/14/2016] [Indexed: 12/15/2022] Open
Abstract
Syphilis is a prominent disease in low- and middle-income countries, and a re-emerging public health threat in high-income countries. Syphilis elimination will require development of an effective vaccine that has thus far remained elusive. Here we assess the vaccine potential of Tp0751, a vascular adhesin from the causative agent of syphilis, Treponema pallidum subsp. pallidum. Tp0751-immunized animals exhibit a significantly reduced bacterial organ burden upon T. pallidum challenge compared with unimmunized animals. Introduction of lymph nodes from Tp0751-immunized, T. pallidum-challenged animals to naive animals fails to induce infection, confirming sterile protection. These findings provide evidence that Tp0751 is a promising syphilis vaccine candidate. There are no vaccines for the prevention of syphilis, a disease caused by the bacterium Treponema pallidum subsp. pallidum. Here, the authors use an animal model of infection to show that immunization with the Tp0751 bacterial protein inhibits the pathogen's spread within the body.
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Affiliation(s)
- Karen V Lithgow
- Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada
| | - Rebecca Hof
- Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada
| | - Charmaine Wetherell
- Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada
| | - Drew Phillips
- Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada
| | - Simon Houston
- Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada
| | - Caroline E Cameron
- Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada
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Radolf JD, Deka RK, Anand A, Šmajs D, Norgard MV, Yang XF. Treponema pallidum, the syphilis spirochete: making a living as a stealth pathogen. Nat Rev Microbiol 2016; 14:744-759. [PMID: 27721440 DOI: 10.1038/nrmicro.2016.141] [Citation(s) in RCA: 151] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The past two decades have seen a worldwide resurgence in infections caused by Treponema pallidum subsp. pallidum, the syphilis spirochete. The well-recognized capacity of the syphilis spirochete for early dissemination and immune evasion has earned it the designation 'the stealth pathogen'. Despite the many hurdles to studying syphilis pathogenesis, most notably the inability to culture and to genetically manipulate T. pallidum, in recent years, considerable progress has been made in elucidating the structural, physiological, and regulatory facets of T. pallidum pathogenicity. In this Review, we integrate this eclectic body of information to garner fresh insights into the highly successful parasitic lifestyles of the syphilis spirochete and related pathogenic treponemes.
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Affiliation(s)
- Justin D Radolf
- Departments of Medicine, Pediatrics, Genetics and Genomic Science, Molecular Biology and Biophysics, and Immunology, UConn Health, 263 Farmington Avenue, Farmington, Connecticut 06030-3715, USA
| | - Ranjit K Deka
- Department of Microbiology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9048, USA
| | - Arvind Anand
- Department of Medicine, UConn Health, 263 Farmington Avenue, Farmington, Connecticut 06030-3715, USA
| | - David Šmajs
- Department of Biology, Faculty of Medicine, Masaryk University, 625 00 Brno, Czech Republic
| | - Michael V Norgard
- Department of Microbiology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9048, USA
| | - X Frank Yang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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Abstract
INTRODUCTION Syphilis, caused by the spirochete Treponema pallidum subspecies pallidum, continues to be a globally prevalent disease despite remaining susceptible to penicillin treatment. Syphilis vaccine development is a viable preventative approach that will serve to complement public health-oriented syphilis prevention, screening and treatment initiatives to deliver a two-pronged approach to stemming disease spread worldwide. Areas covered: This article provides an overview of the need for development of a syphilis vaccine, summarizes significant information that has been garnered from prior syphilis vaccine studies, discusses the critical aspects of infection that would have to be targeted by a syphilis vaccine, and presents the current understanding within the field of the correlates of protection needed to be achieved through vaccination. Expert commentary: Syphilis vaccine development should be considered a priority by industry, regulatory and funding agencies, and should be appropriately promoted and supported.
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Affiliation(s)
- Karen V Lithgow
- a Department of Biochemistry and Microbiology , University of Victoria , Victoria , Canada
| | - Caroline E Cameron
- a Department of Biochemistry and Microbiology , University of Victoria , Victoria , Canada
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Gottlieb SL, Deal CD, Giersing B, Rees H, Bolan G, Johnston C, Timms P, Gray-Owen SD, Jerse AE, Cameron CE, Moorthy VS, Kiarie J, Broutet N. The global roadmap for advancing development of vaccines against sexually transmitted infections: Update and next steps. Vaccine 2016; 34:2939-2947. [PMID: 27105564 PMCID: PMC6759054 DOI: 10.1016/j.vaccine.2016.03.111] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 03/31/2016] [Indexed: 11/09/2022]
Abstract
In 2014, the World Health Organization, the US National Institutes of Health, and global technical partners published a comprehensive roadmap for development of new vaccines against sexually transmitted infections (STIs). Since its publication, progress has been made in several roadmap activities: obtaining better epidemiologic data to establish the public health rationale for STI vaccines, modeling the theoretical impact of future vaccines, advancing basic science research, defining preferred product characteristics for first-generation vaccines, and encouraging investment in STI vaccine development. This article reviews these overarching roadmap activities, provides updates on research and development of individual vaccines against herpes simplex virus, Chlamydia trachomatis, Neisseria gonorrhoeae, and Treponema pallidum, and discusses important next steps to advance the global roadmap for STI vaccine development.
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Affiliation(s)
| | - Carolyn D Deal
- National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | | | - Helen Rees
- Wits Reproductive Health and HIV Institute, University of the Witswatersrand, Johannesburg, South Africa
| | - Gail Bolan
- Centers for Disease Control and Prevention, Atlanta, GA, USA
| | | | - Peter Timms
- University of Sunshine Coast, Queensland Australia and Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
| | | | - Ann E Jerse
- Uniformed Services University, Bethesda, MD, USA
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Marra CM, Tantalo LC, Sahi SK, Dunaway SB, Lukehart SA. Reduced Treponema pallidum-Specific Opsonic Antibody Activity in HIV-Infected Patients With Syphilis. J Infect Dis 2015; 213:1348-54. [PMID: 26655298 DOI: 10.1093/infdis/jiv591] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 11/30/2015] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Human immunodeficiency virus (HIV)-infected individuals may have poorer serological responses to syphilis treatment and may be more likely to experience neurosyphilis. Treponema pallidum is cleared from sites of infection by opsonization, ingestion, and killing by macrophages. METHODS Serum samples from 235 individuals with syphilis were tested for T. pallidum-specific opsonic activity. Blood T. pallidum concentrations were determined by real-time polymerase chain reaction amplification of the tp0574 gene, and T. pallidum was detected in cerebrospinal fluid (CSF) by reverse-transcriptase polymerase chain reaction of 16S ribosomal RNA. RESULTS Opsonic activity was higher with higher serum rapid plasma reagin titers (P < .001), and in those treated for uncomplicated syphilis before serum collection (P < .001). Opsonic activity was lower in HIV-infected than in HIV-uninfected individuals even after the above factors were taken into account (P = .006). In participants in whom blood T. pallidum was detectable, those with the highest opsonic activity had lower blood T. pallidum concentrations. In multivariable analyses, there was not a significant relationship between opsonic activity and detection of T. pallidum in CSF or CSF-VDRL reactivity. CONCLUSIONS Serum T. pallidum-specific opsonic activity is significantly lower in HIV-infected individuals. Impaired T. pallidum-specific immune responses could contribute to differences in the course of disease or treatment response.
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Affiliation(s)
| | | | | | | | - Sheila A Lukehart
- Department Medicine (Infectious Diseases) Department Global Health, Harborview Medical Center, University of Washington, Seattle
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44
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Čejková D, Strouhal M, Norris SJ, Weinstock GM, Šmajs D. A Retrospective Study on Genetic Heterogeneity within Treponema Strains: Subpopulations Are Genetically Distinct in a Limited Number of Positions. PLoS Negl Trop Dis 2015; 9:e0004110. [PMID: 26436423 PMCID: PMC4593590 DOI: 10.1371/journal.pntd.0004110] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 09/02/2015] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Pathogenic uncultivable treponemes comprise human and animal pathogens including agents of syphilis, yaws, bejel, pinta, and venereal spirochetosis in rabbits and hares. A set of 10 treponemal genome sequences including those of 4 Treponema pallidum ssp. pallidum (TPA) strains (Nichols, DAL-1, Mexico A, SS14), 4 T. p. ssp. pertenue (TPE) strains (CDC-2, Gauthier, Samoa D, Fribourg-Blanc), 1 T. p. ssp. endemicum (TEN) strain (Bosnia A) and one strain (Cuniculi A) of Treponema paraluisleporidarum ecovar Cuniculus (TPLC) were examined with respect to the presence of nucleotide intrastrain heterogeneous sites. METHODOLOGY/PRINCIPAL FINDINGS The number of identified intrastrain heterogeneous sites in individual genomes ranged between 0 and 7. Altogether, 23 intrastrain heterogeneous sites (in 17 genes) were found in 5 out of 10 investigated treponemal genomes including TPA strains Nichols (n = 5), DAL-1 (n = 4), and SS14 (n = 7), TPE strain Samoa D (n = 1), and TEN strain Bosnia A (n = 5). Although only one heterogeneous site was identified among 4 tested TPE strains, 16 such sites were identified among 4 TPA strains. Heterogeneous sites were mostly strain-specific and were identified in four tpr genes (tprC, GI, I, K), in genes involved in bacterial motility and chemotaxis (fliI, cheC-fliY), in genes involved in cell structure (murC), translation (prfA), general and DNA metabolism (putative SAM dependent methyltransferase, topA), and in seven hypothetical genes. CONCLUSIONS/SIGNIFICANCE Heterogeneous sites likely represent both the selection of adaptive changes during infection of the host as well as an ongoing diversifying evolutionary process.
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Affiliation(s)
- Darina Čejková
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
- Department of Immunology, Veterinary Research Institute, Brno, Czech Republic
| | - Michal Strouhal
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Steven J. Norris
- Pathology & Laboratory Medicine, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - George M. Weinstock
- The Genome Institute, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - David Šmajs
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
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45
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Foley J. Mini-review: Strategies for Variation and Evolution of Bacterial Antigens. Comput Struct Biotechnol J 2015; 13:407-16. [PMID: 26288700 PMCID: PMC4534519 DOI: 10.1016/j.csbj.2015.07.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 07/18/2015] [Accepted: 07/19/2015] [Indexed: 12/29/2022] Open
Abstract
Across the eubacteria, antigenic variation has emerged as a strategy to evade host immunity. However, phenotypic variation in some of these antigens also allows the bacteria to exploit variable host niches as well. The specific mechanisms are not shared-derived characters although there is considerable convergent evolution and numerous commonalities reflecting considerations of natural selection and biochemical restraints. Unlike in viruses, mechanisms of antigenic variation in most bacteria involve larger DNA movement such as gene conversion or DNA rearrangement, although some antigens vary due to point mutations or modified transcriptional regulation. The convergent evolution that promotes antigenic variation integrates various evolutionary forces: these include mutations underlying variant production; drift which could remove alleles especially early in infection or during life history phases in arthropod vectors (when the bacterial population size goes through a bottleneck); selection not only for any particular variant but also for the mechanism for the production of variants (i.e., selection for mutability); and overcoming negative selection against variant production. This review highlights the complexities of drivers of antigenic variation, in particular extending evaluation beyond the commonly cited theory of immune evasion. A deeper understanding of the diversity of purpose and mechanisms of antigenic variation in bacteria will contribute to greater insight into bacterial pathogenesis, ecology and coevolution with hosts.
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Affiliation(s)
- Janet Foley
- 1320 Tupper Hall, Veterinary Medicine and Epidemiology, UC Davis, Davis, CA 95616, United States
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Giacani L, Brandt SL, Ke W, Reid TB, Molini BJ, Iverson-Cabral S, Ciccarese G, Drago F, Lukehart SA, Centurion-Lara A. Transcription of TP0126, Treponema pallidum putative OmpW homolog, is regulated by the length of a homopolymeric guanosine repeat. Infect Immun 2015; 83:2275-89. [PMID: 25802057 PMCID: PMC4432754 DOI: 10.1128/iai.00360-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 03/17/2015] [Indexed: 12/12/2022] Open
Abstract
An effective mechanism for introduction of phenotypic diversity within a bacterial population exploits changes in the length of repetitive DNA elements located within gene promoters. This phenomenon, known as phase variation, causes rapid activation or silencing of gene expression and fosters bacterial adaptation to new or changing environments. Phase variation often occurs in surface-exposed proteins, and in Treponema pallidum subsp. pallidum, the syphilis agent, it was reported to affect transcription of three putative outer membrane protein (OMP)-encoding genes. When the T. pallidum subsp. pallidum Nichols strain genome was initially annotated, the TP0126 open reading frame was predicted to include a poly(G) tract and did not appear to have a predicted signal sequence that might suggest the possibility of its being an OMP. Here we show that the initial annotation was incorrect, that this poly(G) is instead located within the TP0126 promoter, and that it varies in length in vivo during experimental syphilis. Additionally, we show that TP0126 transcription is affected by changes in the poly(G) length consistent with regulation by phase variation. In silico analysis of the TP0126 open reading frame based on the experimentally identified transcriptional start site shortens this hypothetical protein by 69 amino acids, reveals a predicted cleavable signal peptide, and suggests structural homology with the OmpW family of porins. Circular dichroism of recombinant TP0126 supports structural homology to OmpW. Together with the evidence that TP0126 is fully conserved among T. pallidum subspecies and strains, these data suggest an important role for TP0126 in T. pallidum biology and syphilis pathogenesis.
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Affiliation(s)
- Lorenzo Giacani
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Stephanie L Brandt
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Wujian Ke
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA Graduate School, Southern Medical University, Guangzhou, People's Republic of China, and Division of STD, Guangdong Provincial Center for STI & Skin Diseases Control and Prevention, Guangzhou, People's Republic of China
| | - Tara B Reid
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Barbara J Molini
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Stefanie Iverson-Cabral
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Giulia Ciccarese
- Department of Dermatology, IRCCS Azienda Universitaria Ospedaliera San Martino-IST, Genoa, Italy
| | - Francesco Drago
- Department of Dermatology, IRCCS Azienda Universitaria Ospedaliera San Martino-IST, Genoa, Italy
| | - Sheila A Lukehart
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Arturo Centurion-Lara
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA
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Anand A, LeDoyt M, Karanian C, Luthra A, Koszelak-Rosenblum M, Malkowski MG, Puthenveetil R, Vinogradova O, Radolf JD. Bipartite Topology of Treponema pallidum Repeat Proteins C/D and I: OUTER MEMBRANE INSERTION, TRIMERIZATION, AND PORIN FUNCTION REQUIRE A C-TERMINAL β-BARREL DOMAIN. J Biol Chem 2015; 290:12313-31. [PMID: 25805501 PMCID: PMC4424362 DOI: 10.1074/jbc.m114.629188] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 03/20/2015] [Indexed: 11/06/2022] Open
Abstract
We previously identified Treponema pallidum repeat proteins TprC/D, TprF, and TprI as candidate outer membrane proteins (OMPs) and subsequently demonstrated that TprC is not only a rare OMP but also forms trimers and has porin activity. We also reported that TprC contains N- and C-terminal domains (TprC(N) and TprC(C)) orthologous to regions in the major outer sheath protein (MOSP(N) and MOSP(C)) of Treponema denticola and that TprC(C) is solely responsible for β-barrel formation, trimerization, and porin function by the full-length protein. Herein, we show that TprI also possesses bipartite architecture, trimeric structure, and porin function and that the MOSP(C)-like domains of native TprC and TprI are surface-exposed in T. pallidum, whereas their MOSP(N)-like domains are tethered within the periplasm. TprF, which does not contain a MOSP(C)-like domain, lacks amphiphilicity and porin activity, adopts an extended inflexible structure, and, in T. pallidum, is tightly bound to the protoplasmic cylinder. By thermal denaturation, the MOSP(N) and MOSP(C)-like domains of TprC and TprI are highly thermostable, endowing the full-length proteins with impressive conformational stability. When expressed in Escherichia coli with PelB signal sequences, TprC and TprI localize to the outer membrane, adopting bipartite topologies, whereas TprF is periplasmic. We propose that the MOSP(N)-like domains enhance the structural integrity of the cell envelope by anchoring the β-barrels within the periplasm. In addition to being bona fide T. pallidum rare outer membrane proteins, TprC/D and TprI represent a new class of dual function, bipartite bacterial OMP.
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Affiliation(s)
| | | | | | | | | | - Michael G Malkowski
- the Hauptman-Woodward Medical Research Institute and Department of Structural Biology, State University of New York, Buffalo, New York 14203, and
| | | | - Olga Vinogradova
- Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut 06269
| | - Justin D Radolf
- From the Departments of Medicine, Pediatrics, Molecular Biology and Biophysics, Genetics and Genomic Science, and Immunology, University of Connecticut Health Center, Farmington, Connecticut 06030,
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Russell MW, Whittum-Hudson J, Fidel PL, Hook EW, Mestecky J. Immunity to Sexually Transmitted Infections. Mucosal Immunol 2015. [DOI: 10.1016/b978-0-12-415847-4.00112-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Reid TB, Molini BJ, Fernandez MC, Lukehart SA. Antigenic variation of TprK facilitates development of secondary syphilis. Infect Immun 2014; 82:4959-67. [PMID: 25225245 PMCID: PMC4249288 DOI: 10.1128/iai.02236-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 09/04/2014] [Indexed: 12/11/2022] Open
Abstract
Although primary syphilis lesions heal spontaneously, the infection is chronic, with subsequent clinical stages. Healing of the primary chancre occurs as antibodies against outer membrane antigens facilitate opsonophagocytosis of the bacteria by activated macrophages. TprK is an outer membrane protein that undergoes antigenic variation at 7 variable regions, and variants are selected by immune pressure. We hypothesized that individual TprK variants escape immune clearance and seed new disseminated lesions to cause secondary syphilis. As in human syphilis, infected rabbits may develop disseminated secondary skin lesions. This study explores the nature of secondary syphilis, specifically, the contribution of antigenic variation to the development of secondary lesions. Our data from the rabbit model show that the odds of secondary lesions containing predominately TprK variant treponemes is 3.3 times higher than the odds of finding TprK variants in disseminated primary lesions (odds ratio [OR] = 3.3 [95% confidence interval {CI}, 0.98 to 11.0]; P = 0.055) and that 96% of TprK variant secondary lesions are likely seeded by single treponemes. Analysis of antibody responses demonstrates significantly higher antibody titers to tprK variable region sequences found in the inoculum compared to reactivity to tprK variant sequences found in newly arising secondary lesions. This suggests that tprK variants escape the initial immune response raised against the V regions expressed in the inoculum. These data further support a role for TprK in immune evasion and suggest that the ability of TprK variants to persist despite a robust immune response is instrumental in the development of later stages of syphilis.
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Affiliation(s)
- Tara B Reid
- Interdisciplinary Graduate Program in Pathobiology, Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Barbara J Molini
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Mark C Fernandez
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Sheila A Lukehart
- Interdisciplinary Graduate Program in Pathobiology, Department of Global Health, University of Washington, Seattle, Washington, USA Department of Medicine, University of Washington, Seattle, Washington, USA
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50
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Staudová B, Strouhal M, Zobaníková M, Cejková D, Fulton LL, Chen L, Giacani L, Centurion-Lara A, Bruisten SM, Sodergren E, Weinstock GM, Smajs D. Whole genome sequence of the Treponema pallidum subsp. endemicum strain Bosnia A: the genome is related to yaws treponemes but contains few loci similar to syphilis treponemes. PLoS Negl Trop Dis 2014; 8:e3261. [PMID: 25375929 PMCID: PMC4222731 DOI: 10.1371/journal.pntd.0003261] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 09/10/2014] [Indexed: 02/03/2023] Open
Abstract
Background T. pallidum subsp. endemicum (TEN) is the causative agent of bejel (also known as endemic syphilis). Clinical symptoms of syphilis and bejel are overlapping and the epidemiological context is important for correct diagnosis of both diseases. In contrast to syphilis, caused by T. pallidum subsp. pallidum (TPA), TEN infections are usually spread by direct contact or contaminated utensils rather than by sexual contact. Bejel is most often seen in western Africa and in the Middle East. The strain Bosnia A was isolated in 1950 in Bosnia, southern Europe. Methodology/Principal Findings The complete genome of the Bosnia A strain was amplified and sequenced using the pooled segment genome sequencing (PSGS) method and a combination of three next-generation sequencing techniques (SOLiD, Roche 454, and Illumina). Using this approach, a total combined average genome coverage of 513× was achieved. The size of the Bosnia A genome was found to be 1,137,653 bp, i.e. 1.6–2.8 kbp shorter than any previously published genomes of uncultivable pathogenic treponemes. Conserved gene synteny was found in the Bosnia A genome compared to other sequenced syphilis and yaws treponemes. The TEN Bosnia A genome was distinct but very similar to the genome of yaws-causing T. pallidum subsp. pertenue (TPE) strains. Interestingly, the TEN Bosnia A genome was found to contain several sequences, which so far, have been uniquely identified only in syphilis treponemes. Conclusions/Significance The genome of TEN Bosnia A contains several sequences thought to be unique to TPA strains; these sequences very likely represent remnants of recombination events during the evolution of TEN treponemes. This finding emphasizes a possible role of repeated horizontal gene transfer between treponemal subspecies in shaping the Bosnia A genome. Uncultivable treponemes represent bacterial species and subspecies that are obligate pathogens of humans and animals causing diseases with distinct clinical manifestations. Treponema pallidum subsp. pallidum causes sexually transmitted syphilis, a multistage disease characterized in humans by localized, disseminated, and chronic forms of infection, whereas Treponema pallidum subsp. pertenue (agent of yaws) and Treponema pallidum subsp. endemicum (agent of bejel) cause milder, non-venereally transmitted diseases affecting skin, bones and joints. The genetic basis of the pathogenesis and evolution of these microorganisms are still unknown. In this study, a high quality whole genome sequence of the T. pallidum subsp. endemicum Bosnia A strain was obtained using a combination of next-generation sequencing approaches and compared to the genomes of available uncultivable pathogenic treponemes. Relative to all known genomes of Treponema pallidum subspecies, no major genome rearrangements were found in the Bosnia A. The Bosnia A strain clustered with other yaws-causing strains, while syphilis-causing strains clustered separately. In general, the Bosnia A genome showed similar genetic characteristics to yaws treponemes but also contained several sequences thought to be unique to syphilis-causing strains. This finding suggests a possible role of repeated horizontal gene transfer between treponemal subspecies in shaping the Bosnia A genome.
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Affiliation(s)
- Barbora Staudová
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Michal Strouhal
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic; The Genome Institute, Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Marie Zobaníková
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Darina Cejková
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic; The Genome Institute, Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Lucinda L Fulton
- The Genome Institute, Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Lei Chen
- The Genome Institute, Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Lorenzo Giacani
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Arturo Centurion-Lara
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | | | - Erica Sodergren
- The Genome Institute, Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - George M Weinstock
- The Genome Institute, Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - David Smajs
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
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