scholarly journals Cloning, Expression, and Biophysical Investigations of Truncated Inclusion Protein A (IncA) from Chlamydia trachomatis

2014 ◽  
Author(s):  
Catrina Campbell
Keyword(s):  
Chlamydia Trachomatis ◽  
Protein A ◽  
Inclusion Protein

scholarly journals Comparative Genomic Analysis of Chlamydia trachomatis Oculotropic and Genitotropic Strains

2005 ◽  
Vol 73 (10) ◽  
pp. 6407-6418 ◽  
Author(s):  
John H. Carlson ◽  
Stephen F. Porcella ◽  
Grant McClarty ◽  
Harlan D. Caldwell
Keyword(s):  
Chlamydia Trachomatis ◽  
Protein A ◽  
Transmitted Disease ◽  
Genomic Analysis ◽  
Hla Class I ◽  
Comparative Genomic ◽  
Toxin Gene ◽  
Snp Analysis ◽  
Tryptophan Synthase ◽  
T Cell Epitopes

ABSTRACT Chlamydia trachomatis infection is an important cause of preventable blindness and sexually transmitted disease (STD) in humans. C. trachomatis exists as multiple serovariants that exhibit distinct organotropism for the eye or urogenital tract. We previously reported tissue-tropic correlations with the presence or absence of a functional tryptophan synthase and a putative GTPase-inactivating domain of the chlamydial toxin gene. This suggested that these genes may be the primary factors responsible for chlamydial disease organotropism. To test this hypothesis, the genome of an oculotropic trachoma isolate (A/HAR-13) was sequenced and compared to the genome of a genitotropic (D/UW-3) isolate. Remarkably, the genomes share 99.6% identity, supporting the conclusion that a functional tryptophan synthase enzyme and toxin might be the principal virulence factors underlying disease organotropism. Tarp (translocated actin-recruiting phosphoprotein) was identified to have variable numbers of repeat units within the N and C portions of the protein. A correlation exists between lymphogranuloma venereum serovars and the number of N-terminal repeats. Single-nucleotide polymorphism (SNP) analysis between the two genomes highlighted the minimal genetic variation. A disproportionate number of SNPs were observed within some members of the polymorphic membrane protein (pmp) autotransporter gene family that corresponded to predicted T-cell epitopes that bind HLA class I and II alleles. These results implicate Pmps as novel immune targets, which could advance future chlamydial vaccine strategies. Lastly, a novel target for PCR diagnostics was discovered that can discriminate between ocular and genital strains. This discovery will enhance epidemiological investigations in nations where both trachoma and chlamydial STD are endemic.

scholarly journals Immunoelectron microscopic localization of chlamydial lipopolysaccharide (LPS) in McCoy cells inoculated with Chlamydia trachomatis.

1991 ◽  
Vol 39 (8) ◽  
pp. 1067-1075 ◽  
Author(s):  
S A Hearn ◽  
G L McNabb
Keyword(s):  
Chlamydia Trachomatis ◽  
Plasma Membranes ◽  
Cultured Cells ◽  
Protein A ◽  
Host Cells ◽  
Permeabilized Cells ◽  
Outer Membranes ◽  
Acrylic Resins ◽  
Embedding Methods

Interactions between Chlamydia trachomatis, host cells, and the immune system are believed to involve lipopolysaccharide (LPS). We used immunogold techniques to study the distribution of chlamydial LPS in cultured cells infected with C. trachomatis LGV-L1. McCoy cells inoculated with C. trachomatis were cultured and then fixed and embedded in situ with acrylic resins. Sections were immunolabeled with a protein A-gold method using antisera to the genus-specific, periodate-sensitive epitope on chlamydial LPS. Pre-embedding immunogold labeling on permeabilized cells was also done. By post-embedding methods, labeling for LPS was equally abundant over the outer membranes of elementary (EB) and reticulate bodies (RB). By post-embedding labeling, the sub-surface side of the EB outer membrane was more heavily labeled than the surface side. By pre-embedding labeling, LPS was found to be less abundant on the surface of EBs than RBs. Labeling for LPS was found over apparent lysosomes in McCoy cells and over electron-dense blebs on or near the surface of the plasma membranes of McCoy cells. These results indicate that the concentration of LPS in chlamydial membranes is constant during development but that with development its location changes from being mostly cell-surface to sub-surface. These results show that the post-embedding immunogold technique can be a useful approach for the cell culture-based study of chlamydial LPS.

scholarly journals Investigating the Epidemiology of Repeat Chlamydia trachomatis Detection after Treatment by Using C. trachomatis OmpA Genotyping

2014 ◽  
Vol 53 (2) ◽  
pp. 546-549 ◽  
Author(s):  
Richa Kapil ◽  
Christen G. Press ◽  
M. Lisa Hwang ◽  
LaDraka Brown ◽  
William M. Geisler
Keyword(s):  
Chlamydia Trachomatis ◽  
Sexual Partner ◽  
Protein A ◽  
Genotype Distribution ◽  
Gene Encoding ◽  
Content Type ◽  
Sexually Transmitted ◽  
Infection Treatment ◽  
Outer Membrane Protein A

RepeatChlamydia trachomatisdetection frequently occurs within months afterC. trachomatisinfection treatment. The origins of such infection (persistence versus reinfection from untreated or new partners) are varied and difficult to determine.C. trachomatisstrains can be differentiated by sequencing theompAgene encoding the outer membrane protein A (OmpA). We used OmpA genotyping to investigate the epidemiology of repeatC. trachomatisdetection after treatment inC. trachomatis-infected subjects seen at a sexually transmitted diseases clinic. Subjects were enrolled, tested forC. trachomatis, treated with azithromycin, and scheduled for a 6-month follow-up for repeatC. trachomatistesting. OmpA genotyping was performed onC. trachomatis-positive urogenital specimens obtained from patients at enrollment and follow-up. The enrollment visit OmpA genotypes forC. trachomatiswere determined for 162 subjects (92% female, 94% African American).C. trachomatiswas detected at follow-up in 39 subjects (24%). The OmpA genotype distribution at enrollment did not differ in those with versus those without repeatC. trachomatisdetection. Of the 35 subjects withC. trachomatisstrains genotyped at enrollment and follow-up, 7 (20%) had the sameompAsequence at both visits, while 28 (80%) had discordant sequences. A new sexual partner was reported more often in subjects with discordantC. trachomatisstrains than in those with concordant strains (13 [46%] versus 1 [14%];P= 0.195). Half of the subjects with discordantC. trachomatisstrains who reported sexual activity since treatment denied a new sexual partner; 62% of these subjects reported that their partner was treated. Our study demonstrates that most repeatC. trachomatisdetections after treatment were new infections with a differentC. trachomatisstrain rather than reinfection with the same strain. OmpA genotyping can be a useful tool in understanding the origins of repeatC. trachomatisdetection after treatment.

scholarly journals Comparison of genovars and Chlamydia trachomatis infection loads in ocular samples from children in two distinct cohorts in Sudan and Morocco

2021 ◽  
Vol 15 (8) ◽  
pp. e0009655
Author(s):  
Ehsan Ghasemian ◽  
Aleksandra Inic-Kanada ◽  
Astrid Collingro ◽  
Lamiss Mejdoubi ◽  
Hadeel Alchalabi ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Outer Membrane ◽  
Real Time ◽  
Bacterial Load ◽  
Protein A ◽  
Healthy Controls ◽  
Geographical Differences ◽  
Chlamydia Trachomatis Infection ◽  
Membrane Complex ◽  
Moroccan Patients

Trachoma is a blinding disease caused by repeated conjunctival infection with different Chlamydia trachomatis (Ct) genovars. Ct B genovars have been associated with more severe trachoma symptoms. Here, we investigated associations between Ct genovars and bacterial loads in ocular samples from two distinct geographical locations in Africa, which are currently unclear. We tested ocular swabs from 77 Moroccan children (28 with trachomatous inflammation-follicular (TF) and 49 healthy controls), and 96 Sudanese children (54 with TF and 42 healthy controls) with a Ct-specific real-time polymerase chain reaction (PCR) assay. To estimate bacterial loads, Ct-positive samples were further processed by multiplex real-time qPCR to amplify the chromosomal outer membrane complex B and plasmid open reading frame 2 of Ct. Genotyping was performed by PCR-based amplification of the outer membrane protein A gene (~1120 base pairs) of Ct and Sanger sequencing. Ct-positivities among the Moroccan and Sudanese patient groups were 60·7% and 31·5%, respectively. Significantly more Sudanese patients than Moroccan patients were genovar A-positive. In contrast, B genovars were significantly more prevalent in Moroccan patients than in Sudanese patients. Significantly higher Ct loads were found in samples positive for B genovars (598·596) than A genovar (51·005). Geographical differences contributed to the distributions of different ocular Ct genovars. B genovars may induce a higher bacterial load than A genovars in trachoma patients. Our findings emphasize the importance of conducting broader studies to elucidate if the noted difference in multiplication abilities are genovar and/or endemicity level dependent.

scholarly journals High-resolution genotyping of Lymphogranuloma Venereum (LGV) strains of Chlamydia trachomatis in London using multi-locus VNTR analysis-ompA genotyping (MLVA-ompA)

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254233
Author(s):  
Chloe Manning ◽  
Colette O’Neill ◽  
Ian N. Clarke ◽  
Monica Rebec ◽  
Penelope R. Cliff ◽  
...  
Keyword(s):  
High Resolution ◽  
Chlamydia Trachomatis ◽  
Protein A ◽  
Lymphogranuloma Venereum ◽  
Nucleic Acid Amplification ◽  
Study Population ◽  
Monitoring And Surveillance ◽  
Sex With Men ◽  
The Uk ◽  
Vntr Analysis

Background Lymphogranuloma venereum (LGV) is caused by Chlamydia trachomatis strains with ompA genotypes L1 to L3. An LGV epidemic associated with the L2b genotype has emerged in the past few decades amongst men who have sex with men (MSM). C. trachomatis genotypes can be discriminated by outer membrane protein A gene (ompA) sequencing, however this method has limited resolution. This study employed a high-resolution genotyping method, namely, multi-locus tandem repeat (VNTR) analysis with ompA sequencing (MLVA-ompA), to assess the distribution of LGV MLVA-ompA genotypes amongst individuals attending genitourinary medicine (GUM) clinics in London. Methods Clinical specimens were collected from individuals attending eight London-based GUM clinics. Specimens that tested positive for C. trachomatis by commercial nucleic acid amplification test (NAAT) were confirmed as LGV by pmpH real-time PCR. LGV-positive DNA extracts were subsequently genotyped using MLVA-ompA. Results Two hundred and thirty DNA extracts were confirmed as LGV, and 162 (70%) yielded complete MLVA-ompA genotypes. Six LGV MLVA-ompA genotypes were identified: 1.9.2b-L2, 1.9.3b-L2b, 1.9.2b-L2b, 1.9.2b-L2b/D, 1.4a.2b-L2b, and 5.9.2b-L1. The following LGV ompA genotypes were identified (in descending order of abundance): L2, L2b, L2b/D, and L1. Eight ompA sequences with the hybrid L2b/D profile were detected. The hybrid sequence was identical to the ompA of a recombinant L2b/D strain detected in Portugal in 2017. Conclusions The L2 ompA genotype was found to predominate in the London study population. The study detected an unusual hybrid L2b/D ompA profile that was previously reported in Portugal. We recommend further monitoring and surveillance of LGV strains within the UK population.

scholarly journals Designing a Multi-Epitope Vaccine against Chlamydia trachomatis by Employing Integrated Core Proteomics, Immuno-Informatics and In Silico Approaches

Biology ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 997
Author(s):  
Sidra Aslam ◽  
Sajjad Ahmad ◽  
Fatima Noor ◽  
Usman Ali Ashfaq ◽  
Farah Shahid ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Type Iii Secretion ◽  
In Silico ◽  
Protein A ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Family Type ◽  
T Cell Epitopes ◽  
Type Iii ◽  
Mhc Molecules

Chlamydia trachomatis, a Gram-negative bacterium that infects the rectum, urethra, congenital sites, and columnar epithelium of the cervix. It is a major cause of preventable blindness, ectopic pregnancy, and bacterial sexually transmitted infections worldwide. There is currently no licensed multi-epitope vaccination available for this pathogen. This study used core proteomics, immuno-informatics, and subtractive proteomics approaches to identify the best antigenic candidates for the development of a multi-epitope-based vaccine (MEBV). These approaches resulted in six vaccine candidates: Type III secretion system translocon subunit CopD2, SctW family type III secretion system gatekeeper subunit CopN, SycD/LcrH family type III secretion system chaperone Scc2, CT847 family type III secretion system effector, hypothetical protein CTDEC_0668, and CHLPN 76kDa-like protein. A variety of immuno-informatics tools were used to predict B and T cell epitopes from vaccine candidate proteins. An in silico vaccine was developed using carefully selected epitopes (11 CTL, 2 HTL & 10 LBL) and then docked with the MHC molecules (MHC I & MHC II) and human TLR4. The vaccine was coupled with Cholera toxin subunit B (CTB) adjuvant to boost the immune response. Molecular dynamics (MD) simulations, molecular docking, and MMGBSA analysis were carried out to analyze the molecular interactions and binding affinity of MEBV with TLR4 and MHC molecules. To achieve the highest level of vaccine protein expression, the MEBV was cloned and reverse-translated in Escherichia coli. The highest level of expression was achieved, and a CAI score of 0.97 was reported. Further experimental validation of the MEBV is required to prove its efficacy. The vaccine developed will be useful in preventing infections caused by C. trachomatis.

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