scholarly journals Chlamydia trachomatis Outer Membrane Complex Protein B (OmcB) Is Processed by the Protease CPAF

2012 ◽  
Vol 195 (5) ◽  
pp. 951-957 ◽  
Author(s):  
S. Hou ◽  
L. Lei ◽  
Z. Yang ◽  
M. Qi ◽  
Q. Liu ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Outer Membrane ◽  
Membrane Complex ◽  
Complex Protein ◽  
Protein B

scholarly journals Characterization of Pgp3, a Chlamydia trachomatis Plasmid-Encoded Immunodominant Antigen

2010 ◽  
Vol 192 (22) ◽  
pp. 6017-6024 ◽  
Author(s):  
Ding Chen ◽  
Lei Lei ◽  
Chunxue Lu ◽  
Ahmad Galaleldeen ◽  
P. John Hart ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Outer Membrane ◽  
Expression System ◽  
Sodium Dodecyl ◽  
Structural Basis ◽  
Human Antibody ◽  
Human Immune System ◽  
Human Antibodies ◽  
Membrane Complex ◽  
Nonionic Detergents

ABSTRACT Human antibody recognition of Chlamydia trachomatis plasmid-encoded Pgp3 protein is dependent on the native conformation of Pgp3. The structural basis for the conformation dependence and the function of Pgp3 remain unknown. Here, we report that Pgp3 trimerization is required for the recognition of Pgp3 by human antibodies. In a native polyacrylamide gel, Pgp3 purified from a bacterial expression system migrated as stable trimers that were dissociated into monomers only by treatment with urea or sodium dodecyl sulfate (SDS) but not nonionic detergents. Human antibodies recognized trimeric but not monomeric Pgp3, suggesting that Pgp3 is presented to the human immune system as trimers during C. trachomatis infection. The endogenous Pgp3 secreted into the chlamydial outer membrane complex or host cell cytosol is always trimerized. Intact Pgp3 trimers were eluted from the outer membrane complex by a combination of nonionic detergents with reducing agents but not by the presence of either alone. These observations have provided important information for further understanding the role of Pgp3 in chlamydial pathogenesis and potentially optimizing Pgp3 as a subunit vaccine candidate antigen.

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 A Chlamydia trachomatis OmcB C-Terminal Fragment Is Released into the Host Cell Cytoplasm and Is Immunogenic in Humans

2011 ◽  
Vol 79 (6) ◽  
pp. 2193-2203 ◽  
Author(s):  
Manli Qi ◽  
Siqi Gong ◽  
Lei Lei ◽  
Quanzhong Liu ◽  
Guangming Zhong
Keyword(s):  
Chlamydia Trachomatis ◽  
Host Cell ◽  
Host Cells ◽  
Content Type ◽  
Membrane Complex ◽  
Host Cell Cytoplasm ◽  
Complex Protein ◽  
Infected Cells ◽  
Cell Cytosol ◽  
Host Cell Cytosol

ABSTRACTTheChlamydia trachomatisouter membrane complex protein B (OmcB) is an antigen with diagnostic and vaccine relevance. To further characterize OmcB, we generated antibodies against OmcB C-terminal (OmcBc) and N-terminal (OmcBn) fragments. Surprisingly, the anti-OmcBc antibody detected dominant signals in the host cell cytosol, while the anti-OmcBn antibody exclusively labeled intrainclusion signals inC. trachomatis-infected cells permeabilized with saponin. Western blot analyses revealed that OmcB was partially processed into OmcBc and OmcBn fragments. The processed OmcBc was released into host cell cytosol, while the OmcBn and remaining full-length OmcB were retained within the chlamydial inclusions. The organism-associated OmcB epitopes became detectable only after theC. trachomatis-infected cells were permeabilized with strong detergents such as SDS. However, the harsh permeabilization conditions also led to the leakage of the already secreted OmcBc and chlamydia-secreted protease (CPAF) out of the host cells. The OmcBc processing and release occurred in all biovars ofC. trachomatis. Moreover, the released OmcBc but not the retained OmcBn was highly immunogenic inC. trachomatis-infected women, which is consistent with the concept that exposure of chlamydial proteins to host cell cytosol is accompanied by increased immunogenicity. These observations have provided important information for further exploring/optimizing OmcB as a target for the development of diagnosis methods and vaccines.

Membrane proteins PmpG and PmpH are major constituents of Chlamydia trachomatis L2 outer membrane complex

2000 ◽  
Vol 186 (2) ◽  
pp. 163-169 ◽  
Author(s):  
Per Holse Mygind ◽  
Gunna Christiansen ◽  
Peter Roepstorff ◽  
Svend Birkelund
Keyword(s):  
Chlamydia Trachomatis ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
Membrane Complex

scholarly journals Performance ofChlamydia trachomatisOmcB Enzyme-Linked Immunosorbent Assay in Serodiagnosis ofChlamydia trachomatisInfection in Women

2018 ◽  
Vol 56 (9) ◽  
Author(s):  
Kanupriya Gupta ◽  
LaDraka' Brown ◽  
Rakesh K. Bakshi ◽  
Christen G. Press ◽  
Xiaofei Chi ◽  
...  
Keyword(s):  
African Americans ◽  
Chlamydia Trachomatis ◽  
Antibody Response ◽  
Immunosorbent Assay ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Elementary Body ◽  
Content Type ◽  
Membrane Complex ◽  
Complex Protein

ABSTRACTChlamydia trachomatisserological assays with improved sensitivity over commercially available assays are needed to evaluate the burden ofC. trachomatisinfection and the effectiveness of prevention efforts. We evaluated the performance of aC. trachomatisouter membrane complex protein B (OmcB) enzyme-linked immunosorbent assay (ELISA) in the detection of anti-C. trachomatisantibody responses inC. trachomatis-infected women. OmcB ELISA was less sensitive than ourC. trachomatiselementary body (EB) ELISA, but it was highly specific. The magnitude of the antibody response was higher in African-Americans and those with priorC. trachomatisinfection. Unlike EB ELISA, the IgG1 response toC. trachomatisOmcB was short-lived and was not maintained by repeatC. trachomatisinfection.

scholarly journals Identification of Chlamydia trachomatis Outer Membrane Complex Proteins by Differential Proteomics

2010 ◽  
Vol 192 (11) ◽  
pp. 2852-2860 ◽  
Author(s):  
Xiaoyun Liu ◽  
Mary Afrane ◽  
David E. Clemmer ◽  
Guangming Zhong ◽  
David E. Nelson
Keyword(s):  
Mass Spectrometry ◽  
Chlamydia Trachomatis ◽  
Outer Membrane ◽  
Secretion Systems ◽  
Differential Proteomics ◽  
Infectious Particle ◽  
Novel Proteins ◽  
Membrane Complex ◽  
Associated Proteins ◽  
Protein Secretion Systems

ABSTRACT The extracellular chlamydial infectious particle, or elementary body (EB), is enveloped by an intra- and intermolecular cysteine cross-linked protein shell called the chlamydial outer membrane complex (COMC). A few abundant proteins, including the major outer membrane protein and cysteine-rich proteins (OmcA and OmcB), constitute the overwhelming majority of COMC proteins. The identification of less-abundant COMC proteins has been complicated by limitations of proteomic methodologies and the contamination of COMC fractions with abundant EB proteins. Here, we used parallel liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) analyses of Chlamydia trachomatis serovar L2 434/Bu EB, COMC, and Sarkosyl-soluble EB fractions to identify proteins enriched or depleted from COMC. All well-described COMC proteins were specifically enriched in the COMC fraction. In contrast, multiple COMC-associated proteins found in previous studies were strongly enriched in the Sarkosyl-soluble fraction, suggesting that these proteins are not COMC components or are not stably associated with COMC. Importantly, we also identified novel proteins enriched in COMC. The list of COMC proteins identified in this study has provided reliable information for further understanding chlamydial protein secretion systems and modeling COMC and EB structures.

scholarly journals Vaccination with Outer Membrane Complexes Elicits Rapid Protective Immunity to Multidrug-ResistantAcinetobacter baumannii

2010 ◽  
Vol 79 (1) ◽  
pp. 518-526 ◽  
Author(s):  
Michael J. McConnell ◽  
Juan Domínguez-Herrera ◽  
Younes Smani ◽  
Rafael López-Rojas ◽  
Fernando Docobo-Pérez ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Protective Immunity ◽  
Cellular Responses ◽  
Antibiotic Resistant ◽  
Membrane Complex ◽  
Sepsis Model ◽  
Cytokine Levels ◽  
Prophylactic Vaccination ◽  
Resistant Strains ◽  
Established Infection

ABSTRACTAcinetobacter baumanniicauses pneumonias, bacteremias, and skin and soft tissue infections, primarily in the hospitalized setting. The incidence of infections caused byA. baumanniihas increased dramatically over the last 30 years, while at the same time the treatment of these infections has been complicated by the emergence of antibiotic-resistant strains. Despite these trends, no vaccines or antibody-based therapies have been developed for the prevention ofA. baumanniiinfection. In this study, an outer membrane complex vaccine consisting of multiple surface antigens from the bacterial membrane ofA. baumanniiwas developed and tested in a murine sepsis model. Immunization elicited humoral and cellular responses that were able to reduce postinfection bacterial loads, reduce postinfection proinflammatory cytokine levels in serum, and protect mice from infection with human clinical isolates ofA. baumannii. A single administration of the vaccine was able to elicit protective immunity in as few as 6 days postimmunization. In addition, vaccine antiserum was used successfully to therapeutically rescue naïve mice with established infection. These results indicate that prophylactic vaccination and antibody-based therapies based on an outer membrane complex vaccine may be viable approaches to preventing the morbidity and mortality caused by this pathogen.

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