scholarly journals Estimation of Full-Length TprK Diversity in Treponema pallidum subspecies pallidum

2020 ◽  
Author(s):  
Amin Addetia ◽  
Michelle Lin ◽  
Quynh Phung ◽  
Hong Xie ◽  
Meei-Li Huang ◽  
...  
Keyword(s):  
Immune System ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Deep Sequencing ◽  
Outer Membrane Protein ◽  
Treponema Pallidum ◽  
The United States ◽  
Full Length ◽  
Public Health Issue ◽  
Variable Regions

AbstractImmune evasion and disease progression of Treponema pallidum subspecies pallidum are associated with sequence diversity in the hypervariable, putative outer membrane protein TprK. Previous attempts to study variation within TprK have sequenced at depths insufficient to fully appreciate the hypervariable nature of the protein, failed to establish linkage between the protein’s 7 variable regions, or were conducted on strains passed through rabbits. As a consequence, a complete profiling of tprK during infection in the human host is still lacking. Furthermore, prior studies examining how T. pallidum uses its repertoire of genomic donor sites to generate diversity within the V regions of the tprK also yielded a partial understanding of this process, due to the limited number of tprK alleles examined. In this study, we used short- and long-read deep sequencing to directly characterize full-length tprK alleles from T. pallidum collected from early lesions of patients attending two STD clinics in Italy. Our data, combined with recent data available on Chinese T. pallidum strains, show the near complete absence of overlap in TprK sequences among the 41 strains profiled to date. Moreover, our data allowed us to redefine the boundaries of tprK V regions, identify 55 donor sites, and estimate the total number of TprK variants that T. pallidum can potentially generate. Altogether, our results support how T. pallidum TprK antigenic variation system is an unsurmountable obstacle for the human immune system to naturally achieve infection eradication, and reiterate the importance of this mechanism for pathogen persistence in the host.ImportanceSyphilis continues to be a significant public health issue in both low- and high-income nations, including the United States, where the number of infectious syphilis cases has increased dramatically over the past five years. T. pallidum, the causative agent of syphilis, encodes an outer membrane protein TprK that undergoes segmental gene conversion to constantly create new sequences. We performed deep TprK profiling to understand full-length TprK diversity in T. pallidum-positive clinical specimens and compared these to all samples for which TprK deep sequencing is available. We found almost no overlap in TprK sequences between different patients. We further estimate that the total baseline junctional diversity of full-length TprK rivals that of current estimates of the human adaptive immune system. These data underscore the immunoevasive ability of TprK that allows T. pallidum to establish lifelong infection.

scholarly journals Estimation of Full-Length TprK Diversity in Treponema pallidum subsp. pallidum

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Amin Addetia ◽  
Michelle J. Lin ◽  
Quynh Phung ◽  
Hong Xie ◽  
Meei-Li Huang ◽  
...  
Keyword(s):  
Immune System ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Deep Sequencing ◽  
Outer Membrane Protein ◽  
Treponema Pallidum ◽  
The United States ◽  
Full Length ◽  
Variable Regions ◽  
Content Type

ABSTRACT Immune evasion and disease progression of Treponema pallidum subsp. pallidum are associated with sequence diversity in the hypervariable outer membrane protein TprK. Previous attempts to study variation within TprK have sequenced at depths insufficient to fully appreciate the hypervariable nature of the protein, failed to establish linkage between the protein’s seven variable regions, or were conducted on isolates passed through rabbits. As a consequence, a complete profile of tprK during infection in the human host is still lacking. Furthermore, prior studies examining how T. pallidum subsp. pallidum uses its repertoire of genomic donor sites to generate diversity within the variable regions of the tprK have yielded a partial understanding of this process due to the limited number of tprK alleles examined. In this study, we used short- and long-read deep sequencing to directly characterize full-length tprK alleles from T. pallidum subsp. pallidum collected from early lesions of patients attending two sexually transmitted infection clinics in Italy. We demonstrate that strains collected from cases of secondary syphilis contain significantly more unique variable region sequences and full-length TprK sequences than those from cases of primary syphilis. Our data, combined with recent data available on Chinese T. pallidum subsp. pallidum specimens, show the near-complete absence of overlap in TprK sequences among the 41 specimens profiled to date. We further estimate that the potential antigenic variability carried by TprK rivals that of current estimates of the human adaptive immune system. These data underscore the immunoevasive ability of TprK that allows T. pallidum subsp. pallidum to establish lifelong infection. IMPORTANCE Syphilis continues to be a significant public health issue in both low- and high-income countries, including the United States where the rate of syphilis infection has increased over the past 5 years. Treponema pallidum subsp. pallidum, the causative agent of syphilis, carries the outer membrane protein TprK that undergoes segmental gene conversion to constantly create new sequences. We performed full-length deep sequencing of TprK to examine TprK diversity in clinical T. pallidum subsp. pallidum strains. We then combined our results with data from all samples for which TprK deep sequencing results were available. We found almost no overlap in TprK sequences between different patients. Moreover, our data allowed us to estimate the total number of TprK variants that T. pallidum subsp. pallidum can potentially generate. Our results support how the T. pallidum subsp. pallidum TprK antigenic variation system is an equal adversary of the human immune system leading to pathogen persistence in the host.

scholarly journals Expression of Multiple Outer Membrane Protein Sequence Variants from a Single Genomic Locus of Anaplasma phagocytophilum

2003 ◽  
Vol 71 (4) ◽  
pp. 1706-1718 ◽  
Author(s):  
A. F. Barbet ◽  
P. F. M. Meeus ◽  
M. Bélanger ◽  
M. V. Bowie ◽  
J. Yi ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Disease Transmission ◽  
Anaplasma Phagocytophilum ◽  
Outer Membrane Proteins ◽  
The United States ◽  
Variable Regions ◽  
Genomic Expression ◽  
Expression Site

ABSTRACT Anaplasma phagocytophilum is the causative agent of an emerging tick-borne zoonosis in the United States and Europe. The organism causes a febrile illness accompanied by other nonspecific symptoms and can be fatal, especially if treatment is delayed. Persistence of A. phagocytophilum within mammalian reservoir hosts is important for ensuring continued disease transmission. In the related organism Anaplasma marginale, persistence is associated with antigenic variation of the immunoprotective outer membrane protein MSP2. Extensive diversity of MSP2 is achieved by combinatorial gene conversion of a genomic expression site by truncated pseudogenes. The major outer membrane protein of A. phagocytophilum, MSP2(P44), is homologous to MSP2 of A. marginale, has a similar organization of conserved and variable regions, and is also encoded by a multigene family containing some truncated gene copies. This suggests that the two organisms could use similar mechanisms to generate diversity in outer membrane proteins from their small genomes. We define here a genomic expression site for MSP2(P44) in A. phagocytophilum. As in A. marginale, the msp2(p44) gene in this expression site is polymorphic in all populations of organisms we have examined, whether organisms are obtained from in vitro culture in human HL-60 cells, from culture in the tick cell line ISE6, or from infected human blood. Changes in culture conditions were found to favor the growth and predominance of certain msp2(p44) variants. Insertions, deletions, and substitutions in the region of the genomic expression site encoding the central hypervariable region matched sequence polymorphisms in msp2(p44) mRNA. These data suggest that, similarly to A. marginale, A. phagocytophilum uses combinatorial mechanisms to generate a large array of outer membrane protein variants. Such gene polymorphism has profound implications for the design of vaccines, diagnostic tests, and therapy.

scholarly journals Porin activity and sequence analysis of a 31-kilodalton Treponema pallidum subsp. pallidum rare outer membrane protein (Tromp1).

1995 ◽  
Vol 177 (12) ◽  
pp. 3556-3562 ◽  
Author(s):  
D R Blanco ◽  
C I Champion ◽  
M M Exner ◽  
H Erdjument-Bromage ◽  
R E Hancock ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Treponema Pallidum

scholarly journals Sequence Polymorphism, Predicted Secondary Structures, and Surface-Exposed Conformational Epitopes of Campylobacter Major Outer Membrane Protein

2000 ◽  
Vol 68 (10) ◽  
pp. 5679-5689 ◽  
Author(s):  
Qijing Zhang ◽  
Jerrel C. Meitzler ◽  
Shouxiong Huang ◽  
Teresa Morishita
Keyword(s):  
Amino Acid ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Major Outer Membrane Protein ◽  
Amino Acid Sequences ◽  
Variable Regions ◽  
Conserved Sequences ◽  
Conformational Epitopes

ABSTRACT The major outer membrane protein (MOMP), a putative porin and a multifunction surface protein of Campylobacter jejuni, may play an important role in the adaptation of the organism to various host environments. To begin to dissect the biological functions and antigenic features of this protein, the gene (designatedcmp) encoding MOMP was identified and characterized from 22 strains of C. jejuni and one strain of C. coli. It was shown that the single-copy cmp locus encoded a protein with characteristics of bacterial outer membrane proteins. Prediction from deduced amino acid sequences suggested that each MOMP subunit consisted of 18 β-strands connected by short periplasmic turns and long irregular external loops. Alignment of the amino acid sequences of MOMP from different strains indicated that there were seven localized variable regions dispersed among highly conserved sequences. The variable regions were located in the putative external loop structures, while the predicted β-strands were formed by conserved sequences. The sequence homology of cmp appeared to reflect the phylogenetic proximity of C. jejuni strains, since strains with identical cmp sequences had indistinguishable or closely related macrorestriction fragment patterns. Using recombinant MOMP and antibodies recognizing linear or conformational epitopes of the protein, it was demonstrated that the surface-exposed epitopes of MOMP were predominantly conformational in nature. These findings are instrumental in the design of MOMP-based diagnostic tools and vaccines.

scholarly journals Structure of the Expression Site Reveals Global Diversity in MSP2 (P44) Variants in Anaplasma phagocytophilum

2006 ◽  
Vol 74 (11) ◽  
pp. 6429-6437 ◽  
Author(s):  
Anthony F. Barbet ◽  
Anna M. Lundgren ◽  
A. Rick Alleman ◽  
Snorre Stuen ◽  
Anneli Bjöersdorff ◽  
...  
Keyword(s):  
United States ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Anaplasma Phagocytophilum ◽  
Animal Species ◽  
The United States ◽  
Genomic Locus ◽  
Global Diversity ◽  
Expression Site

ABSTRACT Anaplasma phagocytophilum, a recently reclassified bacteria in the order Rickettsiales, infects many different animal species and causes an emerging tick-borne disease of humans. The genome contains a large number of related genes and gene fragments encoding partial or apparently full-length outer membrane protein MSP2 (P44). Previous data using strains isolated from humans in the United States suggest that antigenic diversity results from RecF-mediated conversion of a single MSP2 (P44) expression site by partially homologous donor sequences. However, whether similar mechanisms operate in naturally infected animal species and the extent of global diversity in MSP2 (P44) are unknown. We analyzed the structure and diversity of the MSP2 (P44) expression site in strains derived from the United States and Europe and from infections of different animal species, including wildlife reservoirs. The results show that a syntenic expression site is present in all strains of A. phagocytophilum investigated. This genomic locus contained diverse MSP2 (P44) variants in all infected animals sampled, and variants also differed at different time points during infection. Although similar variants were found among different populations of U.S. origin, there was little sequence identity between U.S. strain variants (including genomic copies from a completely sequenced U.S. strain) and expression site variants infecting sheep and dogs in Norway and Sweden. Finally, the possibility that combinatorial mechanisms can generate additional diversity beyond the basic donor sequence repertoire is supported by the observation of shared sequence blocks throughout the MSP2 (P44) hypervariable region in reservoir hosts. These data suggest similar genetic mechanisms for A. phagocytophilum variation in all hosts but worldwide diversity of the MSP2 (P44) outer membrane protein.

scholarly journals TP0453, a Concealed Outer Membrane Protein of Treponema pallidum, Enhances Membrane Permeability

2005 ◽  
Vol 187 (18) ◽  
pp. 6499-6508 ◽  
Author(s):  
Karsten R. O. Hazlett ◽  
David L. Cox ◽  
Marc Decaffmeyer ◽  
Michael P. Bennett ◽  
Daniel C. Desrosiers ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Nutrient Transport ◽  
Treponema Pallidum ◽  
Protein S ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Membrane Spanning

ABSTRACT The outer membrane of Treponema pallidum, the noncultivable agent of venereal syphilis, contains a paucity of protein(s) which has yet to be definitively identified. In contrast, the outer membranes of gram-negative bacteria contain abundant immunogenic membrane-spanning β-barrel proteins mainly involved in nutrient transport. The absence of orthologs of gram-negative porins and outer membrane nutrient-specific transporters in the T. pallidum genome predicts that nutrient transport across the outer membrane must differ fundamentally in T. pallidum and gram-negative bacteria. Here we describe a T. pallidum outer membrane protein (TP0453) that, in contrast to all integral outer membrane proteins of known structure, lacks extensive β-sheet structure and does not traverse the outer membrane to become surface exposed. TP0453 is a lipoprotein with an amphiphilic polypeptide containing multiple membrane-inserting, amphipathic α-helices. Insertion of the recombinant, nonlipidated protein into artificial membranes results in bilayer destabilization and enhanced permeability. Our findings lead us to hypothesize that TP0453 is a novel type of bacterial outer membrane protein which may render the T. pallidum outer membrane permeable to nutrients while remaining inaccessible to antibody.

scholarly journals Transcriptional and immunological analysis of the putative outer membrane protein and vaccine candidate TprL of Treponema pallidum

2020 ◽  
Author(s):  
Austin M. Haynes ◽  
Mark Fernandez ◽  
Emily Romeis ◽  
Oriol Mitjà ◽  
Kelika A. Konda ◽  
...  
Keyword(s):  
Transcriptional Regulation ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Vaccine Candidate ◽  
Treponema Pallidum ◽  
Phase Variation ◽  
Knowledge Gap ◽  
Transcription Level ◽  
Vaccine Candidates

AbstractBackgroundAn effective syphilis vaccine should elicit antibodies to Treponema pallidum subsp. pallidum (T. p. pallidum) surface antigens to induce pathogen clearance through opsonophagocytosis. Although the combination of bioinformatics, structural, and functional analyses of T. p. pallidum genes to identify putative outer membrane proteins (OMPs) resulted in a list of potential vaccine candidates, still very little is known about whether and how transcription of these genes is regulated during infection. This knowledge gap is a limitation to vaccine design, as immunity generated to an antigen that can be down-regulated or even silenced at the transcriptional level without affecting virulence would not induce clearance of the pathogen, hence allowing disease progression.Principal findingsWe report here that tp1031, the T. p. pallidum gene encoding the putative OMP and vaccine candidate TprL is differentially expressed in several T. p. pallidum strains, suggesting transcriptional regulation. Experimental identification of the tprL transcriptional start site revealed that a homopolymeric G sequence of varying length resides within the tprL promoter and that its length affects promoter activity compatible with phase variation. Conversely, in the closely related pathogen T. p. subsp. pertenue, the agent of yaws, where a naturally-occurring deletion has eliminated the tprL promoter region, elements necessary for protein synthesis, and part of the gene ORF, tprL transcription level are negligible compared to T. p. pallidum strains. Accordingly, the humoral response to TprL is absent in yaws-infected laboratory animals and patients compared to syphilis-infected subjects.ConclusionThe ability of T. p. pallidum to stochastically vary tprL expression should be considered in any vaccine development effort that includes this antigen. The role of phase variation in contributing to T. p. pallidum antigenic diversity should be further studied.Author SummarySyphilis is still an endemic disease in many low- and middle-income countries and has been resurgent in high-income nations for almost two decades now. In endemic areas, syphilis still causes significant morbidity and mortality in patients, particularly when its causative agent, the bacterium Treponema pallidum subsp. pallidum is transmitted to the fetus during pregnancy. Although there are significant ongoing efforts to identify an effective syphilis vaccine to bring into clinical trials within the decade in the U.S., such efforts are partially hindered by the lack of knowledge on transcriptional regulation of many genes encoding vaccine candidates. Here, we start addressing this knowledge gap for the putative outer membrane protein (OMP) and vaccine candidates TprL, encoded by the tp1031 gene. As we previously reported for other putative OMP-encoding genes of the syphilis agent, tprL transcription level appears to be affected by the length of a homopolymeric sequence of guanosines (Gs) located within the gene promoter. This is a mechanism known as phase variation and often involved in altering the surface antigenic profile of a bacterial pathogen to facilitate immune evasion and/or adaptation to the host milieu.

Sign in / Sign up

Export Citation Format

Share Document