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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: 2.0] [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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Gao ZX, Gou Y, Liu XQ, Peng LW. Advances in laboratory diagnostic methods for cerebrospinal fluid testing for neurosyphilis. Front Public Health 2022; 10:1030480. [PMID: 36452956 PMCID: PMC9703065 DOI: 10.3389/fpubh.2022.1030480] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 10/28/2022] [Indexed: 11/16/2022] Open
Abstract
Neurosyphilis is a chronic infectious disease caused by the invasion of Treponema pallidum into the central nervous system. In recent years, with the increase in the latent syphilis infection rate, the incidence of neurosyphilis has gradually increased, the typical symptoms of neurosyphilis have decreased, atypical manifestations have increased, and the clinical manifestations have become increasingly diverse. Cerebrospinal fluid testing plays an important role in the diagnosis of neurosyphilis. In recent years, there have been many advances in cerebrospinal fluid testing. This review focuses on the current and potential laboratory indicators of neurosyphilis in cerebrospinal fluid, aiming to provide a reference for clinical application and ideas for future experimental research of neurosyphilis.
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Affiliation(s)
- Zheng-Xiang Gao
- Department of Laboratory Medicine, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
| | - Yu Gou
- Department of Laboratory Medicine, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
| | - Xiao-Qin Liu
- Department of Laboratory Medicine, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
| | - Lei-Wen Peng
- Department of Laboratory Medicine, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
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3
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Theel ES, Katz SS, Pillay A. Molecular and Direct Detection Tests for Treponema pallidum Subspecies pallidum: A Review of the Literature, 1964-2017. Clin Infect Dis 2021; 71:S4-S12. [PMID: 32578865 PMCID: PMC7312206 DOI: 10.1093/cid/ciaa176] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Direct detection methods for Treponema pallidum include dark-field microscopy (DFM), direct fluorescence antibody (DFA) testing, immunohistochemistry (IHC), and nucleic acid amplification tests (NAATs). Here, we reviewed the relevant syphilis diagnostic literature to address 2 main questions with respect to T. pallidum direct detection techniques: “What are the performance characteristics for each direct detection test for T. pallidum and what are the optimal specimen types for each test?” and “What options are available for T. pallidum molecular epidemiology?” To answer these questions, we searched 5 electronic databases (OVID Medline, OVID Embase, CINAHL, Cochrane Library, and Scopus) from 1964 to 2017 using relevant search terms and identified 1928 articles, of which 37 met our inclusion criteria. DFM and DFA sensitivities ranged from 73% to 100% in cases of primary syphilis; and while sensitivity using silver stain histopathology for T. pallidum was generally low (0%–41%), higher performance characteristics were observed for T. pallidum–specific IHC (49–92%). Different genes have been targeted by T. pallidum–specific NAATs, with the majority of studies indicating that sensitivity is primarily dependent on the type of collected biological sample, with highest sensitivity observed in primary lesion exudate (75–95%). Given the rising incidence of syphilis, the development of direct, Food and Drug Administration–cleared T. pallidum NAATs should be considered an immediate priority.
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Affiliation(s)
- Elitza S Theel
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Samantha S Katz
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Allan Pillay
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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4
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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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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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Surface immunolabeling and consensus computational framework to identify candidate rare outer membrane proteins of Treponema pallidum. Infect Immun 2010; 78:5178-94. [PMID: 20876295 DOI: 10.1128/iai.00834-10] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Treponema pallidum reacts poorly with the antibodies present in rabbit and human syphilitic sera, a property attributed to the paucity of proteins in its outer membrane. To better understand the basis for the syphilis spirochete's "stealth pathogenicity," we used a dual-label, 3-step amplified assay in which treponemes encapsulated in gel microdroplets were probed with syphilitic sera in parallel with anti-FlaA antibodies. A small (approximately 5 to 10%) but reproducible fraction of intact treponemes bound IgG and/or IgM antibodies. Three lines of evidence supported the notion that the surface antigens were likely β-barrel-forming outer membrane proteins (OMPs): (i) surface labeling with anti-lipoidal (VDRL) antibodies was not observed, (ii) immunoblot analysis confirmed prior results showing that T. pallidum glycolipids are not immunoreactive, and (iii) labeling of intact organisms was not appreciably affected by proteinase K (PK) treatment. With this method, we also demonstrate that TprK (TP0897), an extensively studied candidate OMP, and TP0136, a lipoprotein recently reported to be surface exposed, are both periplasmic. Consistent with the immunolabeling studies, TprK was also found to lack amphiphilicity, a characteristic property of β-barrel-forming proteins. Using a consensus computational framework that combined subcellular localization and β-barrel structural prediction tools, we generated ranked groups of candidate rare OMPs, the predicted T. pallidum outer membrane proteome (OMPeome), which we postulate includes the surface-exposed molecules detected by our enhanced gel microdroplet assay. In addition to underscoring the syphilis spirochete's remarkably poor surface antigenicity, our findings help to explain the complex and shifting balance between pathogen and host defenses that characterizes syphilitic infection.
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Kesavalu L, Holt SC, Ebersole JL. Lack of humoral immune protection against Treponema denticola virulence in a murine model. Infect Immun 1999; 67:5736-46. [PMID: 10531223 PMCID: PMC96949 DOI: 10.1128/iai.67.11.5736-5746.1999] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study investigated the characteristics of humoral immune responses to Treponema denticola following primary infection, reinfection, and active immunization, as well as immune protection in mice. Primary infection with T. denticola induced a significant (400-fold) serum immunoglobulin G (IgG) response compared to that in control uninfected mice. The IgG response to reinfection was 20, 000-fold higher than that for control mice and 10-fold higher than that for primary infection. Mice actively immunized with formalin-killed treponemes developed serum antibody levels seven- to eightfold greater than those in animals after primary infection. Nevertheless, mice with this acquired antibody following primary infection or active immunization demonstrated no significant alterations of lesion induction or decreased size of the abscesses following a challenge infection. Mice with primary infection developed increased levels of IgG3, IgG2b, and IgG2a antibodies, with IgG1 being lower than the other subclasses. Reinfected mice developed enhanced IgG2b, IgG2a, and IgG3 and less IgG1. In contrast, immunized mice developed higher IgG1 and lower IgG3 antibody responses to infection. These IgG subclass distributions indicate a stimulation of both Th1 and Th2 activities in development of the humoral immune response to infection and immunization. Our findings also demonstrated a broad antigen reactivity of the serum antibody, which was significantly increased with reinfection and active immunization. Furthermore, serum antibody was effective in vitro in immobilizing and clumping the bacteria but did not inhibit growth or passively prevent the treponemal infection. These observations suggest that humoral immune responses, as manifested by antibody levels, isotype, and antigenic specificity, were not capable of resolving a T. denticola infection.
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Affiliation(s)
- L Kesavalu
- Department of Periodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
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8
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Champion CI, Blanco DR, Exner MM, Erdjument-Bromage H, Hancock RE, Tempst P, Miller JN, Lovett MA. Sequence analysis and recombinant expression of a 28-kilodalton Treponema pallidum subsp. pallidum rare outer membrane protein (Tromp2). J Bacteriol 1997; 179:1230-8. [PMID: 9023206 PMCID: PMC178820 DOI: 10.1128/jb.179.4.1230-1238.1997] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In this study, we report the cloning, sequencing, and expression of the gene encoding a 28-kDa Treponema pallidum subsp. pallidum rare outer membrane protein (TROMP), designated Tromp2. The tromp2 gene encodes a precursor protein of 242 amino acids including a putative signal peptide of 24 amino acids ending in a type I signal peptidase cleavage site of Leu-Ala-Ala. The mature protein of 218 amino acids has a calculated molecular weight of 24,759 and a calculated pI of 7.3. The predicted secondary structure of Tromp2 shows nine transmembrane segments of amphipathic beta-sheets typical of outer membrane proteins. Recombinant Tromp2 (rTromp2) was expressed with its native signal peptide, using a tightly regulated T7 RNA polymerase expression vector. Under high-level expression conditions, rTromp2 fractionated exclusively with the Escherichia coli outer membrane. Antiserum raised against rTromp2 was generated and used to identify native Tromp2 in cellular fractionations. Following Triton X-114 extraction and phase separation of T. pallidum, the 28-kDa Tromp2 protein was detected prominently in the detergent phase. Alkali and high-salt treatment of purified outer membrane from T. pallidum, conditions which remove peripherally associated membrane proteins, demonstrated that Tromp2 is an integral membrane protein. Whole-mount immunoelectron microscopy of E. coli cells expressing rTromp2 showed specific surface antibody binding. These findings demonstrate that Tromp2 is a membrane-spanning outer membrane protein, the second such protein to be identified for T. pallidum.
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Affiliation(s)
- C I Champion
- Department of Microbiology and Immunology, University of California at Los Angeles, 90095, USA
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Blanco DR, Miller JN, Lovett MA. Surface antigens of the syphilis spirochete and their potential as virulence determinants. Emerg Infect Dis 1997; 3:11-20. [PMID: 9126440 PMCID: PMC2627599 DOI: 10.3201/eid0301.970102] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
A unique physical feature of Treponema pallidum, the venereally transmitted agent of human syphilis, is that its outer membrane contains 100-fold less membrane-spanning protein than the outer membranes of typical gram-negative bacteria, a property that has been related to the chronicity of syphilitic infection. These membrane-spanning T. pallidum rare outer membrane proteins, termed TROMPs, represent potential surface-exposed virulence determinants and targets of host immunity. Only recently has the outer membrane of T. pallidum been isolated and its constituent proteins identified. Five proteins of molecular mass 17-, 28-, 31-, 45-, and 65-kDa were outer membrane associated. The 17- and 45-kDa proteins, which are also present in greater amounts with the T. pallidum inner membrane protoplasmic cylinder complex, had been previously characterized lipoproteins and are, therefore, not membrane-spanning but rather membrane-anchored by their lipid moiety. In contrast, the 28-, 31-, and 65-kDa proteins are exclusively associated with the outer membrane. Both the purified native and an Escherichia coli recombinant outer membrane form of the 31-kDa protein, designated Tromp1, exhibit porin activity, thereby confirming the membrane-spanning outer membrane topology of Tromp1. The 28-kDa protein, designated Tromp2, has sequence characteristics in common with membrane-spanning outer membrane proteins and has also been recombinantly expressed in E. coli, where it targets exclusively to the E. coli outer membrane. The 65-kDa protein, designated Tromp3, is present in the least amount relative to Tromps1 and 2. Tromps 1, 2, and 3 were antigenic when tested with serum from infection and immune syphilitic rabbits and humans. These newly identified TROMPs provide a molecular foundation for the future study of syphilis pathogenesis and immunity.
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Affiliation(s)
- D R Blanco
- Dept. Microbiology and Immunology, UCLA School of Medicine 90095, USA.
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10
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Blanco DR, Champion CI, Exner MM, Erdjument-Bromage H, Hancock RE, Tempst P, Miller JN, Lovett MA. Porin activity and sequence analysis of a 31-kilodalton Treponema pallidum subsp. pallidum rare outer membrane protein (Tromp1). J Bacteriol 1995; 177:3556-62. [PMID: 7768866 PMCID: PMC177062 DOI: 10.1128/jb.177.12.3556-3562.1995] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have recently reported the isolation and purification of the Treponema pallidum outer membrane and the identification of its rare protein constituents, including a 31-kDa protein markedly enriched in the outer membrane preparation (D.R. Blanco, K. Reimann, J. Skare, C.I. Champion, D. Foley, M. M. Exner, R. E. W. Hancock, J. N. Miller, and M. A. Lovett, J. Bacteriol. 176:6088-6099, 1994). In this study, we report the cloning, sequencing, and expression of the structural gene which encodes the 31-kDa outer membrane protein, designated Tromp1. The deduced amino acid sequence from the tromp1 gene sequence encodes a 318-amino-acid polypeptide with a putative 40-amino-acid signal peptide. Processing of Tromp1 results in a mature protein with a predicted molecular mass of 30,415 Da and a calculated pI of 6.6. Secondary-structure predictions identified repeated stretches of amphipathic beta-sheets typical of outer membrane protein membrane-spanning sequences. A topological model of Tromp1 containing 14 transmembrane segments is proposed. Specific antiserum against a recombinant Tromp1 fusion protein was generated and was used to identify native Tromp1 in cellular fractionation. Upon Triton X-114 extraction and phase separation of T. pallidum, the 31-kDa Tromp1 protein was detected in the detergent-phase fraction but not in the protoplasmic cylinder or aqueousphase fractions, consistent with a hydrophobic outer membrane protein. Anti-Tromp1 antiserum was also used to identify native Tromp1 purified from whole T. pallidum by Triton X-100 solubilization followed by nondenaturing isoelectric focusing. Reconstitution of purified Tromp1 into planar lipid bilayers showed porin activity based on the measured single channel conductanes of 0.15 and 0.7 nS in 1 M KCl. These findings demonstrate that Tromp1 is a transmembrane outer membrane porin protein of T. pallidum.
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Affiliation(s)
- D R Blanco
- Department of Microbiology and Immunology, School of Medicine, University of California at Los Angeles 90024, USA
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11
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Abstract
Treponema pallidum, the syphilis spirochaete, has a remarkable ability to evade the humoral and cellular responses it elicits in infected hosts. Although formerly attributed to the presence of an outer coat comprised of serum proteins and/or mucopolysaccharides, current evidence indicates that the immuno-evasiveness of this bacterium is largely the result of its unusual molecular architecture. Based upon a combination of molecular, biochemical, and ultrastructural data, it is now believed that the T. pallidum outer membrane (OM) contains a paucity of poorly immunogenic transmembrane proteins ('rare outer membrane proteins') and that its highly immunogenic proteins are lipoproteins anchored predominantly to the periplasmic leaflet of the cytoplasmic membrane. The presence in the T. pallidum OM of a limited number of transmembrane proteins has profound implications for understanding syphilis pathogenesis as well as treponemal physiology. Two major strategies for molecular characterization of rare outer membrane proteins have evolved. The first involves the identification of candidate OM proteins as fusions with Escherichia coli alkaline phosphatase. The second involves the characterization of candidate OM proteins identified in outer membranes isolated from virulent T. pallidum. Criteria to define candidate OM proteins and for definitive identification of rare OM proteins are proposed as a guide for future studies.
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Affiliation(s)
- J D Radolf
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235-9113, USA
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12
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Matsumoto M, Ishikawa F. Purification of Treponema pallidum, Nichols strain, by two-step column chromatography. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL APPLICATIONS 1995; 663:217-24. [PMID: 7735469 DOI: 10.1016/0378-4347(94)00457-g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A rapid and simple purification method for Treponema pallidum, Nichols strain, the etiological agent of venereal syphilis, was developed. A 40-ml suspension of organisms (1.10(9)/ml) was extracted from rabbit testicular tissue and solubilized with a non-ionic detergent, 1-O-n-octyl-beta-D-glucopyranoside. Solubilized antigens were purified by cation-exchange and hydroxyapatite column chromatography. The overall recovery of immunoreactive material was 48.3% and the specific activity increased. Sodium dodecyl sulphate polyacrylamide gel electrophoresis and immunoblotting analysis confirmed the purity and species specificity of the purified antigen.
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Affiliation(s)
- M Matsumoto
- Sekisui Chemical Co., Ltd., Medical Research Laboratory, Osaka, Japan
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13
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Blanco DR, Reimann K, Skare J, Champion CI, Foley D, Exner MM, Hancock RE, Miller JN, Lovett MA. Isolation of the outer membranes from Treponema pallidum and Treponema vincentii. J Bacteriol 1994; 176:6088-99. [PMID: 7928971 PMCID: PMC196829 DOI: 10.1128/jb.176.19.6088-6099.1994] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The outer membranes from Treponema pallidum subsp. pallidum and Treponema vincentii were isolated by a novel method. Purified outer membranes from T. pallidum and T. vincentii following sucrose gradient centrifugation banded at 7 and 31% (wt/wt) sucrose, respectively. Freeze fracture electron microscopy of purified membrane vesicles from T. pallidum and T. vincentii revealed an extremely low density of protein particles; the particle density of T. pallidum was approximately six times less than that of T. vincentii. The great majority of T. vincentii lipopolysaccharide was found in the outer membrane preparation. The T. vincentii outer membrane also contained proteins of 55 and 65 kDa. 125I-penicillin V labeling demonstrated that t. pallidum penicillin-binding proteins were found exclusively with the protoplasmic cylinders and were not detectable with purified outer membrane material, indicating the absence of inner membrane contamination. Isolated T. pallidum outer membrane was devoid of the 19-kDa 4D protein and the normally abundant 47-kDa lipoprotein known to be associated with the cytoplasmic membrane; only trace amounts of the periplasmic endoflagella were detected. Proteins associated with the T. pallidum outer membrane were identified by one- and two-dimensional electrophoretic analysis using gold staining and immunoblotting. Small amounts of strongly antigenic 17- and 45-kDa proteins were detected and shown to correspond to previously identified lipoproteins which are found principally with the cytoplasmic membrane. Less antigenic proteins of 65, 31 (acidic pI), 31 (basic pI), and 28 kDa were identified. Compared with whole-organism preparations, the 65- and the more basic 31-kDa proteins were found to be highly enriched in the outer membrane preparation, indicating that they may represent the T. pallidum rare outer membrane proteins. Reconstitution of solubilized T. pallidum outer membrane into lipid bilayer membranes revealed porin activity with two estimated channel diameters of 0.35 and 0.68 nm based on the measured single-channel conductances in 1 M KCl of 0.40 and 0.76 nS, respectively.
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Affiliation(s)
- D R Blanco
- Department of Microbiology and Immunology, School of Medicine, University of California, Los Angeles 90024
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Radolf JD. Role of outer membrane architecture in immune evasion by Treponema pallidum and Borrelia burgdorferi. Trends Microbiol 1994; 2:307-11. [PMID: 7812663 DOI: 10.1016/0966-842x(94)90446-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Combined ultrastructural and molecular studies have revealed that the syphilis and Lyme-disease spirochetes, Treponema pallidum and Borrelia burgdorferi, have distinctive molecular architectures. Both organisms persist in their hosts and have strategies for immune evasion that include the use of rare, poorly immunogenic surface-exposed proteins as potential virulence determinants.
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Affiliation(s)
- J D Radolf
- Dept of Internal Medicine, University of Texas, Southwestern Medical Center, Dallas 75235
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15
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Stamm LV, Parrish EA. Characterization of the low-molecular-mass proteins of virulent Treponema pallidum. Infect Immun 1994; 62:271-9. [PMID: 8262639 PMCID: PMC186097 DOI: 10.1128/iai.62.1.271-279.1994] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We previously demonstrated that Treponema pallidum cells incubated in vitro in the presence of heat-inactivated normal rabbit serum (HINRS) synthesize, in very small quantities, several pathogen-specific, low-molecular-mass proteins that appear to be localized extracellularly. In this study, we have taken advantage of our ability to metabolically radiolabel T. pallidum cells to high specific activity to further characterize these antigens. We found that the low-molecular-mass proteins are not related to the 15- and 17-kDa detergent-phase proteins (J. D. Radolf, N. R. Chamberlain, A. Clausell, and M. V. Norgard, Infect. Immun. 56:490-498, 1988). The low-molecular-mass proteins did not incorporate 3H-labeled fatty acids and were not precipitated by rabbit immunoglobulin G (IgG) antibodies directed against glutathione S-transferase fusions to the nonlipidated 15- and 17-kDa proteins. We prepared polyclonal antisera to the low-molecular-mass proteins by immunizing two rabbits with the concentrated supernatant of T. pallidum cells. IgG antibodies present in the sera of both rabbits precipitated a 21.5-kDa protein from solubilized extracts of T. pallidum supernatant and cells. IgG antibodies in the serum of the second rabbit precipitated an additional 15.5-kDa low-molecular-mass protein only from solubilized extracts of supernatant. While investigating the effect of eliminating HINRS from the extraction medium, we observed that the low-molecular-mass proteins remained associated with treponemal cells that were incubated in the absence of HINRS. These proteins could be eluted from the cells by the addition of HINRS or rabbit serum albumin, suggesting that they are located on or near the treponemal cell surface. The 15.5- and 21.5-kDa low-molecular-mass proteins were not washed off treponemal cells with buffer containing 1 M KCl. Experiments employing selective solubilization of the T. pallidum outer membrane with 0.1% Triton X-114 and proteinase K accessibility indicated that the 15.5-kDa protein, but not the 21.5-kDa protein, is cell surface exposed.
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Affiliation(s)
- L V Stamm
- Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill 27599-7400
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16
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Norris SJ. Polypeptides of Treponema pallidum: progress toward understanding their structural, functional, and immunologic roles. Treponema Pallidum Polypeptide Research Group. Microbiol Rev 1993; 57:750-79. [PMID: 8246847 PMCID: PMC372934 DOI: 10.1128/mr.57.3.750-779.1993] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Treponema pallidum subsp. pallidum, the spirochete that causes syphilis, is unusual in a number of respects, including its small genome size, inability to grow under standard in vitro culture conditions, microaerophilism, apparent paucity of outer membrane proteins, structurally complex periplasmic flagella, and ability to evade the host immune responses and cause disease over a period of years to decades. Many of these attributes are related ultimately to its protein content. Our knowledge of the activities, structure, and immunogenicity of its proteins has been expanded by the application of recombinant DNA, hybridoma, and structural fractionation techniques. The purpose of this monograph is to summarize and correlate this new information by using two-dimensional gel electrophoresis, monoclonal antibody reactivity, sequence data, and other properties as the bases of polypeptide identification. The protein profiles of the T. pallidum subspecies causing syphilis, yaws, and endemic syphilis are virtually indistinguishable but differ considerably from those of other treponemal species. Among the most abundant polypeptides are a group of lipoproteins of unknown function that appear to be important in the immune response during syphilitic infection. The periplasmic flagella of T. pallidum and other spirochetes are unique with regard to their protein content and ultrastructure, as well as their periplasmic location. They are composed of three core proteins (homologous to the other members of the eubacterial flagellin family) and a single, unrelated sheath protein; the functional significance of this arrangement is not understood at present. Although the bacterium contains the chaperonins GroEL and DnaK, these proteins are not under the control of the heat shock regulon as they are in most organisms. Studies of the immunogenicity of T. pallidum proteins indicate that many may be useful for immunodiagnosis and immunoprotection. Future goals in T. pallidum polypeptide research include continued elucidation of their structural locations and functional activities, identification and characterization of the low-abundance outer membrane proteins, further study of the immunoprotective and immunodiagnostic potential of T. pallidum proteins, and clarification of the roles of treponemal proteins in pathogenesis.
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Affiliation(s)
- S J Norris
- Department of Pathology, University of Texas Medical School at Houston 77225
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17
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Shaffer JM, Baker-Zander SA, Lukehart SA. Opsonization of Treponema pallidum is mediated by immunoglobulin G antibodies induced only by pathogenic treponemes. Infect Immun 1993; 61:781-4. [PMID: 8423106 PMCID: PMC302795 DOI: 10.1128/iai.61.2.781-784.1993] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Rabbit antisera to Leptospira interrogans, Borrelia hermsii, and Treponema phagedenis biotype Reiter, reactive to shared spirochetal antigens, failed to enhance phagocytosis of Treponema pallidum by macrophages, while immunoglobulin G to Treponema pallidum subsp. pertenue and Treponema paraluiscuniculi promoted phagocytosis. Opsonic antibodies are directed to pathogen-restricted, not shared spirochetal, antigens.
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Affiliation(s)
- J M Shaffer
- Department of Medicine, University of Washington, Seattle 98195
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18
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Cox DL, Chang P, McDowall AW, Radolf JD. The outer membrane, not a coat of host proteins, limits antigenicity of virulent Treponema pallidum. Infect Immun 1992; 60:1076-83. [PMID: 1541522 PMCID: PMC257596 DOI: 10.1128/iai.60.3.1076-1083.1992] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Virulent Treponema pallidum reacts poorly with the specific antibodies present in human and rabbit syphilitic sera, a phenomenon often attributed to an outer coat of host serum proteins. Here we present additional evidence that the limited antigenicity of virulent organisms actually is due to a paucity of proteins in the outer membrane. Initially, we used electron microscopy to demonstrate that the outer membrane is highly susceptible to damage from physical manipulation (i.e., centrifugation and resuspension) and nonionic detergents. Organisms with disrupted outer membranes were markedly more antigenic than intact treponemes as determined by immunoelectron microscopy (IEM) with rabbit syphilitic and antiendoflagellar antisera. Data obtained with a new radioimmunoassay, designated the T. pallidum surface-specific radioimmunoassay, corroborated these IEM findings by demonstrating that the major T. pallidum immunogens are not surface exposed; the assay also was unable to detect serum proteins, including fibronectin, on the surfaces of intact organisms. Furthermore, IEM of T. pallidum on ultrathin cryosections with monospecific anti-47-kDa-immunogen antiserum confirmed the intracellular location of the 47-kDa immunogen. On the basis of these and previous findings, we proposed a new model for T. pallidum ultrastructure in which the outer membrane contains a small number of transmembrane proteins and the major membrane immunogens are anchored by lipids to the periplasmic leaflet of the cytoplasmic membrane. This unique ultrastructure explains the remarkable ability of virulent organisms to evade the humoral immune response of the T. pallidum-infected host.
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Affiliation(s)
- D L Cox
- Treponema Immunobiology Section, National Center for Infectious Diseases, Centers for Disease Control, Atlanta, Georgia 30333
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19
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Walker EM, Borenstein LA, Blanco DR, Miller JN, Lovett MA. Analysis of outer membrane ultrastructure of pathogenic Treponema and Borrelia species by freeze-fracture electron microscopy. J Bacteriol 1991; 173:5585-8. [PMID: 1885536 PMCID: PMC208278 DOI: 10.1128/jb.173.17.5585-5588.1991] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We analyzed the outer membrane (OM) ultrastructure of four pathogenic members of the family Spirochaetaceae by freeze fracture. The OM of Treponema pallidum subsp. pertenue contained a low intramembranous particle concentration, indicating that it contains few OM transmembrane proteins. The concave OM fracture faces of Treponema hyodysenteriae and Borrelia burgdorferi contained dense populations of particles, typical of gram-negative organisms. A relatively low concentration of particles which were evenly divided between a small and a large species was present in the concave OM fracture face of Borrelia hermsii; the convex OM fracture face contained only small particles. As for gram-negative bacteria, the convex OM fracture face particle concentrations of these pathogens were low. These spirochetes cleaved preferentially within the OM, in contrast to typical gram-negative bacteria, which tend to fracture within the inner membrane. The OM ultrastructure of T. pallidum subsp. pertenue provides an explanation for the lack of antigenicity of the treponemal surface and may reflect a mechanism by which this pathogen evades the host immune response.
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Affiliation(s)
- E M Walker
- Department of Microbiology and Immunology, School of Medicine, University of California, Los Angeles 90024
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20
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Alder JD, Friess L, Tengowski M, Schell RF. Phagocytosis of opsonized Treponema pallidum subsp. pallidum proceeds slowly. Infect Immun 1990; 58:1167-73. [PMID: 2182536 PMCID: PMC258605 DOI: 10.1128/iai.58.5.1167-1173.1990] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Macrophages were found to phagocytize Treponema pallidum subsp. pallidum attached to polycarbonate filters. This environment simulated the in vivo interaction of surface-adherent treponemes with macrophages. The phagocytosis of T. pallidum subsp. pallidum was found to proceed slowly. Heat-killed T. pallidum subsp. pallidum were susceptible to opsonization with 2% immune serum, whereas live treponemes were resistant to this concentration of antibody. High concentrations of immune serum were found to increase phagocytosis of the spirochetes. Live T. pallidum subsp. pallidum had bound limited quantities of immunoglobulin G in vivo, and only opsonization with 20% immune serum resulted in a detectable increase in surface-bound immunoglobulin in vitro. Kinetic studies suggested a steady rate of phagocytosis that is considerably slower than with other bacteria. Scanning electron microscopy studies of the phagocytizing macrophages showed that the treponemes were detached from the membrane filters and scooped onto the ruffled portion of the macrophage surface. This lengthy physical process, along with the lack of a dramatic increase in ingestion after opsonization, may account for the slow rate of phagocytosis.
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Affiliation(s)
- J D Alder
- Department of Medical Microbiology and Immunology, University of Wisconsin Medical School, Madison
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21
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Abstract
The treponemes comprise the essentially non-cultivable Treponema pallidum subspecies (agents of syphilis, yaws and other human trepanematoses), the gut pathogen of pigs, T. hydysenteriae, and a group of antigenically related, cultivable species, some of which are strongly implicated in human periodontal or gastrointestinal disease. Technical developments during the last decade have made possible the molecular analysis of components of this diverse group of organisms. Polypeptides and other macromolecular components have been characterized by techniques including electron microscopy, gel electrophoresis and immunoblotting. Antigenic analysis has been greatly enhanced by the use of monoclonal antibodies. Finally, DNA cloning and genetic manipulation have enabled the detailed investigation of important antigens at a genetic, structural and functional level. We examine these developments and provide a current overview of the data now available, which is an important foundation for applications in diagnosis, therapy, and, potentially, immunization against disease.
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Affiliation(s)
- R Strugnell
- Department of Microbiology, Monash University, Melbourne, Australia
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22
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Swancutt MA, Riley BS, Radolf JD, Norgard MV. Molecular characterization of the pathogen-specific, 34-kilodalton membrane immunogen of Treponema pallidum. Infect Immun 1989; 57:3314-23. [PMID: 2680970 PMCID: PMC259808 DOI: 10.1128/iai.57.11.3314-3323.1989] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The 34-kilodalton (kDa) antigen of Treponema pallidum subsp. pallidum (T. pallidum) is a pathogen-specific integral membrane protein. DNA sequence analysis of the cloned gene revealed an open reading frame encoding a primary product of 204 residues with a molecular mass of 22,087 daltons. Sequences that correspond to a consensus Escherichia coli promoter and a ribosome-binding site were found upstream from the AUG start codon that begins the open reading frame, suggesting that the cloned gene can use its own regulatory sequences for expression. Examination of the deduced amino acid sequence revealed the presence of a typical procaryotic leader peptide 19 amino acids long; processing results in a mature molecule with a molecular mass of 20,123 daltons. Pulse-chase experiments with E. coli minicells confirmed that the 34-kDa antigen is synthesized as a higher-molecular-weight precursor that is processed to a mature form with the electrophoretic mobility that is characteristic for this protein. The presence in the leader peptide of the sequence Phe-Ser-Ala-Cys suggested that the 34-kDa antigen is a proteolipid. Although hydropathy analysis of the deduced amino acid sequence of the mature 34-kDa antigen predicted that the molecule was primarily hydrophilic, both the native and recombinant 34-kDa molecules displayed hydrophobic biochemical behavior by fractionating into the detergent phase after extraction of intact organisms with Triton X-114. Cell fractionation experiments with E. coli showed that the 34-kDa molecule was localized in both the inner and outer membranes of the recombinant host. The combined data demonstrate that the 34-kDa antigen is an integral membrane protein that behaves in a biochemically consistent manner in both T. pallidum and E. coli.
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Affiliation(s)
- M A Swancutt
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235
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23
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Walker EM, Zampighi GA, Blanco DR, Miller JN, Lovett MA. Demonstration of rare protein in the outer membrane of Treponema pallidum subsp. pallidum by freeze-fracture analysis. J Bacteriol 1989; 171:5005-11. [PMID: 2670902 PMCID: PMC210310 DOI: 10.1128/jb.171.9.5005-5011.1989] [Citation(s) in RCA: 101] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The surface of Treponema pallidum subsp. pallidum (T. pallidum), the etiologic agent of syphilis, appears antigenically inert and lacks detectable protein, as judged by immunocytochemical and biochemical techniques commonly used to identify the outer membrane (OM) constituents of gram-negative bacteria. We examined T. pallidum by freeze-fracture electron microscopy to visualize the architecture of its OM. Treponema phagedenis biotype Reiter (T. phagedenis Reiter), a nonpathogenic host-associated treponeme, and Spirochaeta aurantia, a free-living spirochete, were studied similarly. Few intramembranous particles interrupted the smooth convex and concave fracture faces of the OM of T. pallidum, demonstrating that the OM of this organism is an unusual, nearly naked lipid bilayer. In contrast, the concave fracture face of the OM of S. aurantia was densely covered with particles, indicating the presence of abundant integral membrane proteins, a feature shared by typical gram-negative organisms. The concentration of particles in the OM concave fracture face of T. phagedenis Reiter was intermediate between those of T. pallidum and S. aurantia. Similar to typical gram-negative bacteria, the OM convex fracture faces of the three spirochetes contained relatively few particles. The unique molecular architecture of the OM of T. pallidum can explain the puzzling in vitro properties of the surface of the organism and may reflect a specific adaptation by which treponemes evade the host immune response.
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Affiliation(s)
- E M Walker
- Department of Microbiology and Immunology, School of Medicine, University of California, Los Angeles 90024
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24
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Pallesen L, Hindersson P. Cloning and sequencing of a Treponema pallidum gene encoding a 31.3-kilodalton endoflagellar subunit (FlaB2). Infect Immun 1989; 57:2166-72. [PMID: 2659537 PMCID: PMC313856 DOI: 10.1128/iai.57.7.2166-2172.1989] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
A library of Treponema pallidum DNA was established in the direct selection vector pUN121. Six clones carrying a gene coding for a 33-kilodalton T. pallidum flagellum subunit were identified by colony hybridization with an oligodeoxynucleotide probe based on the N-terminal amino acid sequence of this subunit. An open reading frame of 286 amino acids with the expected N-terminal sequence and absence of cysteine residues was identified. The deduced protein had a calculated molecular weight of 31.3 kilodaltons. We propose to name this flagellar subunit FlaB2. FlaB2 shows a significant amino acid homology with flagellins of several remotely related bacterial species. This homology was most pronounced corresponding to the C-terminal and N-terminal parts of the protein, whereas the central region was variable.
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Affiliation(s)
- L Pallesen
- Department of Treponematoses, Statens Seruminstitut, Copenhagen, Denmark
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25
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Radolf JD, Norgard MV, Schulz WW. Outer membrane ultrastructure explains the limited antigenicity of virulent Treponema pallidum. Proc Natl Acad Sci U S A 1989; 86:2051-5. [PMID: 2648388 PMCID: PMC286845 DOI: 10.1073/pnas.86.6.2051] [Citation(s) in RCA: 156] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Freeze fracture and deep etching were used to investigate the ultrastructural basis for the observation that anti-treponemal antibodies bind poorly to the surface of virulent Treponema pallidum. Fractures of T. pallidum outer membranes contained scarce, uniformly sized intramembranous particles (IMPs). IMPs on the convex faces often appeared to form linear arrays that wound in spirals about the organism. In contrast to the outer membrane, IMPs of the cytoplasmic membrane were randomly distributed, numerous, and heterogeneous in size. In Escherichia coli and T. pallidum cofractures, IMPs of the E. coli outer membranes were densely packed within the concave fracture faces, while the T. pallidum fractures were identical to the experiments lacking the E. coli internal controls. Outer membranes of two representative nonpathogenic treponemes, Treponema phagedenis biotype Reiter and Treponema denticola, contained numerous IMPs, which segregated preferentially with the concave halves. Examination of apposed replicas and deep-etched specimens indicated that at least some of the IMPs extend through the T. pallidum outer membrane and are exposed on the surface of the organism. The outer membrane of intact T. pallidum appears to contain a paucity of integral membrane proteins that can serve as targets for specific antibodies. These findings appear to represent an unusual parasitic strategy for evasion of host humoral defenses.
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Affiliation(s)
- J D Radolf
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235
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26
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Noordhoek GT, Hermans PW, Paul AN, Schouls LM, van der Sluis JJ, van Embden JD. Treponema pallidum subspecies pallidum (Nichols) and Treponema pallidum subspecies pertenue (CDC 2575) differ in at least one nucleotide: comparison of two homologous antigens. Microb Pathog 1989; 6:29-42. [PMID: 2471912 DOI: 10.1016/0882-4010(89)90005-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In an attempt to identify antigenic differences between Treponema pallidum subsp. pallidum (T. pallidum) and Treponema pallidum subsp. pertenue (T. pertenue) a gene bank of T. pertenue was constructed in lambda vector EMBL3. Clones carrying the T. pertenue gene encoding a 190 kDa protein, TyF1, were selected and the DNA was expressed in E. coli. TyF1 was shown to be closely related, but slightly different from the previously cloned T. pallidum antigen TpF1. TyF1 and TpF1 are high molecular weight antigens of about 190 kDa, which dissociate into 19 kDa subunits after heat treatment in presence of SDS. The difference between the two proteins is most obvious after treatment with proteinase K, which yields a 115 kDa component from TyF1 and a 95 kDa component from TpF1, as determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The structural genes encoding TyF1 and TpF1 were sequenced and the predicted amino acid sequences differed in a single amino acid residue at position 40, which is arginine in TyF1 and glutamine in TpF1. Similarities TyF1 and TpF1 with the previously described 4D antigen are discussed. The antibody response to TyF1 and TpF1 seems higher in syphilis patients than in yaws patients. The possibility of using the difference between these T. pallidum and the T. Pertenue antigens for serological discrimination of syphilis and yaws is discussed.
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Affiliation(s)
- G T Noordhoek
- Laboratory for Bacteriology, National Institute of Public Health and Environmental Hygiene, Bilthoven, The Netherlands
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27
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Cunningham TM, Walker EM, Miller JN, Lovett MA. Selective release of the Treponema pallidum outer membrane and associated polypeptides with Triton X-114. J Bacteriol 1988; 170:5789-96. [PMID: 3056914 PMCID: PMC211684 DOI: 10.1128/jb.170.12.5789-5796.1988] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The effects of the nonionic detergent Triton X-114 on the ultrastructure of Treponema pallidum subsp. pallidum are presented in this study. Treatment of Percoll-purified motile T. pallidum with a 1% concentration of Triton X-114 resulted in cell surface blebbing followed by lysis of blebs and a decrease in diameter from 0.25-0.35 micron to 0.1-0.15 micron. Examination of thin sections of untreated Percoll-purified T. pallidum showed integrity of outer and cytoplasmic membranes. In contrast, thin sections of Triton X-114-treated treponemes showed integrity of the cytoplasmic membrane but loss of the outer membrane. The cytoplasmic cylinders generated by detergent treatment retained their periplasmic flagella, as judged by electron microscopy and immunoblotting. Recently identified T. pallidum penicillin-binding proteins also remained associated with the cytoplasmic cylinders. Proteins released by Triton X-114 at 4 degrees C were divided into aqueous and hydrophobic phases after incubation at 37 degrees C. The hydrophobic phase had major polypeptide constituents of 57, 47, 38, 33-35, 23, 16, and 14 kilodaltons (kDa) which were reactive with syphilitic serum. The 47-kDa polypeptide was reactive with a monoclonal antibody which has been previously shown to identify a surface-associated T. pallidum antigen. The aqueous phase contained the 190-kDa ordered ring molecule, 4D, which has been associated with the surface of the organisms. Full release of the 47- and 190-kDa molecules was dependent on the presence of a reducing agent. These results indicate that 1% Triton X-114 selectively solubilizes the T. pallidum outer membrane and associated proteins of likely outer membrane location.
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Affiliation(s)
- T M Cunningham
- Department of Microbiology and Immunology, University of California, Los Angeles 90024
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28
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Hsu PL, Qin M, Norris SJ, Sell S. Isolation and characterization of recombinant Escherichia coli clones secreting a 24-kilodalton antigen of Treponema pallidum. Infect Immun 1988; 56:1135-43. [PMID: 2833442 PMCID: PMC259774 DOI: 10.1128/iai.56.5.1135-1143.1988] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Escherichia coli clones containing Treponema pallidum DNA in the pUC8 vector and secreting a 24-kilodalton antigen of T. pallidum have been isolated. Both syphilitic human and syphilis-immune rabbit sera reacted with the recombinant p24 antigen, indicating that an equivalent protein in T. pallidum is capable of eliciting antibody responses during natural infections. The p24 antigen of T. pallidum was identified by using two-dimensional gel electrophoresis and immunoblotting with monospecific anti-p24 serum. We tentatively concluded that this cloned antigen is a secreted protein or a labile or minor component of T. pallidum because (i) p24 was secreted by the recombinant E. coli cells; (ii) recombinant p24 in E. coli cells was processed into several smaller species with molecular masses ranging from 12 to 20 kilodaltons, which correlate well with the masses of secreted antigens described by others; and (iii) p24 protein appeared to be highly antigenic during natural infections, but only a very small amount of this antigen was associated with or retained by the purified organisms. The possible role of the p24 protein in determining the growth characteristics of T. pallidum is suggested by the ability of recombinant p24 to induce growth changes in E. coli cells. All E. coli colonies expressing the p24 polypeptide exhibited a flat and rough colony morphology and a filamentous growth pattern that were different from those of other E. coli cells. The DNA sequence coding for the p24 polypeptide is located on a 1.7-kilobase-pair BamHI fragment of the T. pallidum genomic DNA and is absent in the nonpathogenic Treponema phagedenis DNA. However, any possible relationship between the p24 antigen and the virulence of T. pallidum remains to be determined. In preliminary studies, rabbits immunized with the purified p24 were not protected from the infection with live T. pallidum organisms.
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Affiliation(s)
- P L Hsu
- Department of Pathology and Laboratory Medicine, University of Texas Health Science Center at Houston 77225
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29
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Radolf JD, Chamberlain NR, Clausell A, Norgard MV. Identification and localization of integral membrane proteins of virulent Treponema pallidum subsp. pallidum by phase partitioning with the nonionic detergent triton X-114. Infect Immun 1988; 56:490-8. [PMID: 3276627 PMCID: PMC259309 DOI: 10.1128/iai.56.2.490-498.1988] [Citation(s) in RCA: 156] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Integral membrane proteins of Treponema pallidum subsp. pallidum (T. pallidum) were identified by phase partitioning with the nonionic detergent Triton X-114; antigens with apparent molecular masses of 47, 38, 36, 34, 32, 17, and 15 kilodaltons (kDa) were identified in the detergent phase. Immunoblotting with murine monoclonal antibodies directed against pathogen-specific 47- and 34-kDa T. pallidum antigens confirmed their presence in the detergent phase. Endoflagellar proteins of T. pallidum were not detected in immunoblots of detergent-phase proteins when monospecific antisera directed against endoflagella of the nonpathogenic T. phagedenis biotype Reiter were used. At detergent concentrations (0.02 and 0.1%) which appeared to solubilize selectively the outer membranes of treponemes radiolabeled with 35S in vitro, limited amounts of detergent-phase proteins were immunoprecipitated. Greater amounts of detergent-phase proteins were extracted at higher detergent concentrations (0.5 and 2.0%) which resulted in both outer membrane solubilization and ultrastructural derangements of the residual cytoplasmic bodies. Furthermore, Triton X-114 extraction of both intact treponemes and organisms without outer membranes yielded detergent phases with similar protein profiles. The results of these experiments indicate that the hydrophobic proteins identified by Triton X-114 are not located exclusively in the T. pallidum outer membrane. The results are also consistent with the hypothesis that the T. pallidum outer membrane is a protein-deficient lipid bilayer.
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Affiliation(s)
- J D Radolf
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235
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30
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Cunningham TM, Miller JN, Lovett MA. Identification of Treponema pallidum penicillin-binding proteins. J Bacteriol 1987; 169:5298-300. [PMID: 3312170 PMCID: PMC213939 DOI: 10.1128/jb.169.11.5298-5300.1987] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Penicillin-binding proteins of 180, 89, 80, 68, 61, 41, and 38 kilodaltons were identified in Treponema pallidum (Nichols) by their covalent binding of [35S]benzylpenicillin. Penicillin-binding proteins are localized in the plasma membranes of many bacterial species and may serve as useful markers for determining plasma membrane intactness in T. pallidum fractionation studies.
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Affiliation(s)
- T M Cunningham
- Department of Microbiology and Immunology, School of Medicine, University of California, Los Angeles 90024
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Fitzgerald TJ. Activation of the classical and alternative pathways of complement by Treponema pallidum subsp. pallidum and Treponema vincentii. Infect Immun 1987; 55:2066-73. [PMID: 3305362 PMCID: PMC260658 DOI: 10.1128/iai.55.9.2066-2073.1987] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Both in vivo and in vitro studies have indicated that complement plays an important role in the syphilitic immune responses. Few quantitative data are available concerning activation of the classical pathway by Treponema pallidum subsp. pallidum, and no information is available on treponemal activation of the alternative pathway. Activation of both pathways was compared by using T. pallidum subsp. pallidum and the nonpathogen T. vincentii. With rabbit and human sources of complement, both organisms rapidly activated the classical pathway, as shown by hemolysis of sensitized sheep erythrocytes and by the generation of soluble C4a. With human sources of complement, both organisms also activated the alternative pathway, as shown by hemolysis of rabbit erythrocytes and by the generation of soluble C3a in the presence of magnesium ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA). During incubation, organisms remained actively mobile and did not lyse, indicating that activation was a function of complement reactivity with the intact outer treponemal surface. In addition, freshly harvested T. pallidum subsp. pallidum immediately activated both pathways of complement; preincubation of organisms did not enhance complement reactivity. T. vincentii was a more potent activator of this pathway. T. pallidum subsp. pallidum contained almost four times as much surface sialic acid as T. vincentii did. When sialic acid was enzymatically removed from T. pallidum subsp. pallidum, enhanced activation of the alternative pathway was detected. It is proposed that T. pallidum subsp. pallidum retards complement-mediated damage by the alternative pathway through surface-associated sialic acid. This may be an important virulence determinant that enables these organisms to readily disseminate through the bloodstream to infect other tissues.
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Stamm LV, Hodinka RL, Wyrick PB, Bassford PJ. Changes in the cell surface properties of Treponema pallidum that occur during in vitro incubation of freshly extracted organisms. Infect Immun 1987; 55:2255-61. [PMID: 3305368 PMCID: PMC260687 DOI: 10.1128/iai.55.9.2255-2261.1987] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We previously reported that a number of Treponema pallidum membrane proteins appear to reside on the cell surface, since intact treponemes radiolabeled by overnight incubation in medium containing [35S]methionine bind immunoglobulin G (IgG) antibodies directed against these proteins. In the present study, it was found that freshly extracted organisms radiolabeled in vitro for only 2 h inefficiently bound IgG antibodies directed against just two proteins of molecular weights 40,000 and 34,000. An in vitro incubation period of greater than 8 h was required before IgG antibodies present in rabbit syphilitic serum could recognize additional protein antigens on the cell surface. Treatment of aged treponemes, but not freshly extracted organisms, with 0.04% sodium dodecyl sulfate selectively removed a membranous layer from the treponemal surface. Only three treponemal proteins were found associated with this structure, including the same 40,000- and 34,000-molecular-weight proteins mentioned above. These two proteins most likely represent endoflagellar subunits, since they were precipitated with rabbit antisera prepared against purified endoflagellar subunits of the cultivable treponemal strain Treponema phagedenis. Further evidence also was obtained that cells of T. pallidum actively secrete into their extracellular environment a unique class of low-molecular-weight proteins.
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Dallas WS, Ray PH, Leong J, Benedict CD, Stamm LV, Bassford PJ. Identification and purification of a recombinant Treponema pallidum basic membrane protein antigen expressed in Escherichia coli. Infect Immun 1987; 55:1106-15. [PMID: 3552988 PMCID: PMC260476 DOI: 10.1128/iai.55.5.1106-1115.1987] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
A recombinant plasmid designated pLVS3 previously was described that harbored a 14-kilobase insert of Treponema pallidum genomic DNA. Escherichia coli maxicells programmed with this plasmid synthesized three treponemal protein antigens of molecular weights 39,000, 35,000, and 25,000 (39K, 35K, and 25K proteins, respectively). In this study, a detailed deletion analysis of pLVS3 demonstrated that the genetic information for all three protein antigens is contained within a 1.5-kilobase EcoRI-HpaI restriction fragment. The DNA sequence of this fragment revealed a single open reading frame of 361 codons that most likely encodes a signal peptide-bearing precursor to the 39K protein that can be transiently detected in E. coli maxicells. Evidence indicated that the 35K and 25K protein antigens are derivatives of the larger protein and are only produced in maxicells. A significant elevation in expression of the 39K treponemal protein antigen in E. coli was obtained by using the E. coli lpp and lac promoters and a genetic construction in which the signal peptide and first four residues of the "mature" 39K protein were replaced by six amino acids encoded by the vector. This hybrid protein exhibited an unusually high pI, which greatly facilitated its purification to homogeneity. By using antibody prepared against the hybrid protein, the native treponemal protein counterpart, also of molecular weight 39,000, was identified as a membrane component of T. pallidum. Since the native protein also exhibited a net positive charge, it has been designated the T. pallidum basic membrane protein.
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Radolf JD, Borenstein LA, Kim JY, Fehniger TE, Lovett MA. Role of disulfide bonds in the oligomeric structure and protease resistance of recombinant and native Treponema pallidum surface antigen 4D. J Bacteriol 1987; 169:1365-71. [PMID: 3549683 PMCID: PMC211954 DOI: 10.1128/jb.169.4.1365-1371.1987] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Recombinant Treponema pallidum surface antigen 4D isolated from Escherichia coli formed a protease-resistant ordered ring structure composed of 19,000-dalton subunits. On gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the higher oligomers of recombinant 4D migrated with molecular masses that were nearly multiples of the 190,000-dalton basic ordered ring. Reduction at room temperature with 2-mercaptoethanol converted the 190,000-dalton ordered ring and the higher oligomers to a 160,000-dalton form and the dissociated monomer. A 190,000-dalton form of 4D was identified in sodium dodecyl sulfate-solubilized T. pallidum after reduction at room temperature. Disulfide bonds stabilized both native and recombinant 4D oligomers against dissociation by heating in detergent without a reducing agent. Electron microscopy of recombinant 4D revealed that the characteristic ordered ring structure was maintained after reduction. Reduction of 4D under conditions that preserved the ordered ring structure did not affect the resistance of the molecule to digestion with proteinase K. The properties of 4D suggest that it may fulfill an important structural role in the T. pallidum outer membrane.
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Norris SJ, Alderete JF, Axelsen NH, Bailey MJ, Baker-Zander SA, Baseman JB, Bassford PJ, Baughn RE, Cockayne A, Hanff PA, Hindersson P, Larsen SA, Lovett MA, Lukehart SA, Miller JN, Moskophidis MA, Müller F, Norgard MV, Penn CW, Stamm LV, van Embden JD, Wicher K. Identity ofTreponema pallidum subsp.pallidum polypeptides: Correlation of sodium dodecyl sulfate-polyacrylamide gel electrophoresis results from different laboratories. Electrophoresis 1987. [DOI: 10.1002/elps.1150080202] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Tabor DR, Bagasra O, Jacobs RF. Treponemal infection specifically enhances node T-cell regulation of macrophage activity. Infect Immun 1986; 54:21-7. [PMID: 3531014 PMCID: PMC260110 DOI: 10.1128/iai.54.1.21-27.1986] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Hamsters experimentally inoculated in the inguinal region with Treponema pallidum subsp. endemicum develop considerable pathology at that site. We examined the cell populations from these inguinal lymph nodes to determine their intercellular responses to infection. In vitro, syphilitic-node T cells markedly suppressed C3b receptor-mediated ingestion (C3bMI) in syphilitic macrophages derived from sites both proximal and distal to the inoculation. This activity was more pronounced when node T cells rather than peritoneal T cells were used. When treponemal preparations or live treponemes were added to the coculture system, the suppression was specifically enhanced, whereas the addition of heterologous agents did not promote this effect. Syphilitic macrophages from either compartment cultured alone showed no significant inhibition of C3bMI. In parallel studies on syphilitic macrophages, we observed that the expression of Ia quickly became elevated and was sustained throughout the infection. Moreover, in vitro culturing of the syphilitic-node T cells with these macrophages did not alter this function. These observations suggest that the syphilitic node contains a subpopulation of T cells that can selectively suppress macrophage C3bMI activity and concurrently regulate their cellular response to treponemal infection.
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Fehniger TE, Radolf JD, Walfield AM, Cunningham TM, Miller JN, Lovett MA. Native surface association of a recombinant 38-kilodalton Treponema pallidum antigen isolated from the Escherichia coli outer membrane. Infect Immun 1986; 52:586-93. [PMID: 3516880 PMCID: PMC261041 DOI: 10.1128/iai.52.2.586-593.1986] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
A recombinant plasmid designated pAW305, containing a 6-kilobase insert of Treponema pallidum DNA, directed the expression of a 38-kilodalton (kDa) treponemal antigen in Escherichia coli. The 38-kDa antigen copurified with the outer membrane fraction of the E. coli cell envelope after treatment with nonionic detergents or sucrose density gradient centrifugation. Rabbits immunized with the recombinant 38-kDa antigen developed antibodies which reacted specifically with a 38-kDa T. pallidum antigen on immunoblots, and 38-kDa antisera specifically immobilized T. pallidum in a complement-dependent manner in the T. pallidum immobilization test. Antisera to the 38-kDa recombinant antigen were also used to demonstrate its native surface association on T. pallidum by immunoelectron microscopy.
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