Transcriptome of Treponema pallidum: gene expression profile during experimental rabbit infection.
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ABSTRACT:
SUBMITTER: Smajs D
PROVIDER: S-EPMC1063989 | biostudies-literature | 2005 Mar
REPOSITORIES: biostudies-literature
Publications
Transcriptome of Treponema pallidum: gene expression profile during experimental rabbit infection.
Smajs David D McKevitt Matthew M Howell Jerrilyn K JK Norris Steven J SJ Cai Wei-Wen WW Palzkill Timothy T Weinstock George M GM
Journal of bacteriology 20050301 5
RNA transcript levels in the syphilis spirochete Treponema pallidum subsp. pallidum (Nichols) isolated from experimentally infected rabbits were determined by the use of DNA microarray technology. This characterization of the T. pallidum transcriptome during experimental infection provides further insight into the importance of gene expression levels for the survival and pathogenesis of this bacterium. ...[more]
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Project description:The recent development of a system for long-term in vitro culture of the syphilis spirochete, Treponema pallidum subsp. pallidum, has introduced the possibility of detailed genetic analysis of this bacterium. In this study, the in vitro culture system was used to isolate and characterize clonal populations of T. pallidum subsp. pallidum Nichols, the most widely studied strain. In limiting dilutions experiments, it was possible to establish cultures with inocula as low as 0.5 T. pallidum per well despite the long generation time (~35 to 40 hours) of this organism. Six Nichols strain clones isolated by limiting dilution were characterized in detail. All clones exhibited indistinguishable morphology and motility, highly similar in vitro multiplication rates, and comparable infectivity in the rabbit model (ID50 ≤ 100 bacteria). Genomic sequencing revealed sequence heterogeneity in the form of insertions or deletions at 5 sites, single nucleotide variations at 20 sites, and polynucleotide (polyG/C) tract length differences at 22 locations. Genomic sequences of the uncloned Nichols strain preparations propagated in rabbits or in vitro cultures exhibited substantial heterogeneity at these locations, indicating coexistence of many varied 'clonotypes' within these populations. Nearly all genetic variations were specific for the Nichols strain and were not detected in the >280 T. pallidum genomic sequences that are currently available. We hypothesize that these Nichols strain-specific sequence variations arose independently either during human infection or within the 110 years since the strain's initial isolation, and thus represent examples of microevolution and divergence.
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Project description:BackgroundCurrent syphilis tests cannot distinguish between active and past syphilis among patients with serofast rapid plasma reagin (RPR) titers. We investigated whether cytokine profiles might provide insight in the differentiation of active and treated syphilis.MethodsWe collected quarterly serum samples from participants at risk for incident syphilis in a prospective cohort study of men and male-to-female transgender women. We defined incident syphilis as a new RPR titer ≥ 1:8 or a fourfold increase from a prior RPR titer and a positive Treponema pallidum particle agglutination assay. We measured cytokine expression using a 63-multiplex bead-based Luminex assay (eBiosciences/Affymetrix, San Diego, California, USA). We used tertile bins and Chi square tests to identify differences in proportions of cytokines between samples from patients with active and treated syphilis. We constructed a network of cytokine profiles from those findings. We used R software (R version 3.4.1, R, Vienna, Austria) to fit models.ResultsWe identified 20 pairs of cytokines (out of 1953 possible pairs) that differed between active and treated syphilis. From those, we identified three cytokine networks of interest: an Eotaxin-Rantes-Leptin network, a Mig-IL1ra-Trail-CD40L network, and an IL12p40-IL12p70 network.ConclusionsDifferences in cytokine profiles are present among men and male-to-female transgender women with active and treated syphilis. Cytokine assays may be a potentially useful tool for identifying active syphilis among patients with serologic syphilis reactivity.
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Project description:In this study we describe the development of the T-cell response to a panel of Treponema pallidum antigens over the course of syphilis infection in the rabbit and determine whether these antigens induce the expression of Th1 cytokines. It was determined that the membrane proteins TpN17 and TpN47, as well as the endoflagellar sheath protein TpN37, induce strong proliferation responses through most of syphilis infection; Tromp1 induced only weak proliferative responses. An unexpected drop in proliferative response to these antigens at day 90 of infection, followed by a dramatic increase in response at day 180, suggests that there may be a secondary dissemination of T. pallidum which induces a recall response. Crude epitope mapping of TpN17 and TpN37 showed that multiple epitopes may be present on both antigens, which is likely a contributing factor in the immunodominance of these antigens. The T-cell response to the TpN37 molecule shows acquisition of newly recognized epitopes during the course of infection. Sonicated T. pallidum was found to induce the expression of interleukin-2 (IL-2) and gamma interferon and not IL-10 mRNA, showing that the general T-cell response to T. pallidum antigens in syphilis infection is biased towards the Th1 phenotype. Of the antigens tested, TpN37 appears to contribute the most to the Th1 cytokine response and therefore may play a key role in the clearance of T. pallidum from lesions.
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Project description: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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Project description:Two new tprD alleles have been identified in Treponema pallidum: tprD2 is found in 7 of 12 T. pallidum subsp. pallidum isolates and 7 of 8 non-pallidum isolates, and tprD3 is found in one T. pallidum subsp. pertenue isolate. Antibodies against TprD2 are found in persons with syphilis, demonstrating that tprD2 is expressed during infection.
| S-EPMC111288 | biostudies-literature
Project description:The tprK gene in Treponema pallidum undergoes antigenic variation. In all T. pallidum isolates examined to date, except the Nichols type strain, heterogeneous tprK sequences have been identified. This heterogeneity is localized to seven variable (V) regions, and tprK sequence diversity accumulates with serial passage in naïve rabbits. The T. pallidum Nichols genome described a single tprK sequence, and after decades of independent passage, only minor tprK sequence diversity is seen among the Nichols strains from different laboratories. We hypothesized that T. pallidum Nichols is capable of only limited tprK diversification. To address this hypothesis, we passaged the T. pallidum Nichols strain in naïve rabbits at the peak of infection (rapid passage) or after the adaptive immune response had cleared most organisms in vivo (slow passage). After 22 rapid passages (9- to 10-day intervals), no tprK V region sequence changes were observed. In contrast, after two slow passages (30- to 35-day intervals), three V regions had sequences that were completely different from that of the original inoculum. New sequences were observed in all seven V regions by the fifth slow passage. In contrast to the rapid-passaged Nichols strain, rapid-passaged Chicago C, a clonal strain isolated from the highly diverse parent Chicago strain, developed significant tprK diversification. These findings suggest that tprK variation can occur, but at a lower rate, in Nichols and that immune pressure may be required for accumulation of bacteria with diverse tprK sequences. Adaptation to growth in rabbits may explain the limited repertoire of V region sequences seen in the Nichols strain.
| S-EPMC1418662 | biostudies-literature
Project description:The tprK gene of Treponema pallidum subsp. pallidum, the causative agent of venereal syphilis, belongs to a 12-member gene family and encodes a protein with a predicted cleavable signal sequence and predicted transmembrane domains. Except for the Nichols type strain, all rabbit-propagated isolates of T. pallidum examined thus far are comprised of mixed populations of organisms with heterogeneous tprK sequences. We show that tprK sequences in treponemes obtained directly from syphilis patients are also heterogeneous. Clustering analysis demonstrates that primary chancre tprK sequences are more likely to cluster within a sample than among samples and that tighter clustering is seen within chancre samples than within rabbit-propagated isolates. Closer analysis of tprK sequences from a rabbit-propagated isolate reveals that individual variable regions have different levels of diversity, suggesting that variable regions may have different intrinsic rates of sequence change or may be under different levels of selection. Most variable regions show increased sequence diversity upon passage. We speculate that the diversification of tprK during infection allows organisms to evade the host immune response, contributing to reinfection and persistent infection.
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Project description:We investigated Treponema pallidum infection in 8 nonhuman primate species (289 animals) in Tanzania during 2015-2017. We used a serologic treponemal test to detect antibodies against the bacterium. Infection was further confirmed from tissue samples of skin-ulcerated animals by 3 independent PCRs (polA, tp47, and TP_0619). Our findings indicate that T. pallidum infection is geographically widespread in Tanzania and occurs in several species (olive baboons, yellow baboons, vervet monkeys, and blue monkeys). We found the bacterium at 11 of 14 investigated geographic locations. Anogenital ulceration was the most common clinical manifestation; orofacial lesions also were observed. Molecular data show that nonhuman primates in Tanzania are most likely infected with T. pallidum subsp. pertenue-like strains, which could have implications for human yaws eradication.
| S-EPMC6004850 | biostudies-literature