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Lu C, Wang J, Zhong G. Preclinical screen for protection efficacy of chlamydial antigens that are immunogenic in humans. Infect Immun 2023; 91:e0034923. [PMID: 37889004 PMCID: PMC10652899 DOI: 10.1128/iai.00349-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 10/02/2023] [Indexed: 10/28/2023] Open
Abstract
To search for subunit vaccine candidates, immunogenic chlamydial antigens identified in humans were evaluated for protection against both infection and pathology in a mouse genital tract infection model under three different immunization regimens. The intramuscular immunization regimen was first used to evaluate 106 chlamydial antigens, which revealed that two antigens significantly reduced while 11 increased genital chlamydial burden. The two infection-reducing antigens failed to prevent pathology and 23 additional antigens even exacerbated pathology. Thus, intranasal mucosal immunization was tested next since intranasal inoculation with live Chlamydia muridarum prevented both genital infection and pathology. Two of the 29 chlamydial antigens evaluated were found to prevent genital infection but not pathology and three exacerbate pathology. To further improve protection efficacy, a combinational regimen (intranasal priming + intramuscular boosting + a third intraperitoneal/subcutaneous boost) was tested. This regimen identified four infection-reducing antigens, but only one of them prevented pathology. Unfortunately, this protective antigen was not advanced further due to its amino acid sequence homology with several human molecules. Two pathology-exacerbating antigens were also found. Nevertheless, intranasal mucosal priming with viable C. muridarum in control groups consistently prevented both genital infection and pathology regardless of the subsequent boosters. Thus, screening 140 different chlamydial antigens with 21 repeated multiple times in 17 experiments failed to identify a subunit vaccine candidate but demonstrated the superiority of viable chlamydial organisms in inducing immunity against both genital infection and pathology, laying the foundation for developing a live-attenuated Chlamydia vaccine.
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Affiliation(s)
- Chunxue Lu
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, Hunan, China
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Jie Wang
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center, San Antonio, Texas, USA
- Department of Immunology, Xiangya School of Medicine, Central South University, Changsha, Hunan, China
| | - Guangming Zhong
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center, San Antonio, Texas, USA
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2
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Bastidas RJ, Valdivia RH. The emerging complexity of Chlamydia trachomatis interactions with host cells as revealed by molecular genetic approaches. Curr Opin Microbiol 2023; 74:102330. [PMID: 37247566 PMCID: PMC10988583 DOI: 10.1016/j.mib.2023.102330] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 04/24/2023] [Accepted: 04/27/2023] [Indexed: 05/31/2023]
Abstract
Chlamydia trachomatis (Ct) is an intracellular bacterial pathogen that relies on the activity of secreted proteins known as effectors to promote replication and avoidance of immune clearance. Understanding the contribution of Ct effectors to pathogenesis has proven to be challenging, given that these proteins often perform multiple functions during intracellular infection. Recent advances in molecular genetic analysis of Ct have provided valuable insights into the multifaceted nature of secreted effector proteins and their impact on the interaction between Ct and host cells and tissues. This review highlights significant findings from genetic analysis of Ct effector functions, shedding light on their diverse roles. We also discuss the challenges faced in this field of study and explore potential opportunities for further research.
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Affiliation(s)
- Robert J Bastidas
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Raphael H Valdivia
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
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Cheong HC, Cheok YY, Chan YT, Tang TF, Sulaiman S, Looi CY, Gupta R, Arulanandam B, Chang LY, Wong WF. Chlamydia trachomatis plasmid-encoding Pgp3 protein induces secretion of distinct inflammatory signatures from HeLa cervical epithelial cells. BMC Microbiol 2023; 23:58. [PMID: 36870960 PMCID: PMC9985209 DOI: 10.1186/s12866-023-02802-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 02/20/2023] [Indexed: 03/06/2023] Open
Abstract
BACKGROUND Genital Chlamydia trachomatis infection is the most common bacterial sexual transmitted disease that causes severe complications including pelvic inflammatory disease, ectopic pregnancy, and infertility in females. The Pgp3 protein encoded by C. trachomatis plasmid has been speculated to be an important player in chlamydial pathogenesis. However, the precise function of this protein is unknown and thus remains to be thoroughly investigated. METHODS In this study, we synthesized Pgp3 protein for in vitro stimulation in the Hela cervical carcinoma cells. RESULTS AND CONCLUSION We showed that Pgp3 induced prominent expression of host inflammatory cytokine genes including interleukin-6 (IL-6), IL-8, tumor necrosis factor alpha-induced protein 3 (TNFAIP3), and chemokine C-X-C motif ligand 1 (CXCL1), implying a possible role of Pgp3 in modulating the inflammatory reaction in the host.
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Affiliation(s)
- Heng Choon Cheong
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Yi Ying Cheok
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Yee Teng Chan
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Ting Fang Tang
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Sofiah Sulaiman
- Department of Obstetrics and Gynecology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Chung Yeng Looi
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor's University, 47500, Subang Jaya, Selangor, Malaysia
| | - Rishein Gupta
- South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, USA
| | - Bernard Arulanandam
- South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX, USA.,Department of Immunology, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Li-Yen Chang
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Won Fen Wong
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia.
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Cortina ME, Bishop RC, DeVasure BA, Coppens I, Derré I. The inclusion membrane protein IncS is critical for initiation of the Chlamydia intracellular developmental cycle. PLoS Pathog 2022; 18:e1010818. [PMID: 36084160 PMCID: PMC9491573 DOI: 10.1371/journal.ppat.1010818] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 09/21/2022] [Accepted: 08/22/2022] [Indexed: 11/18/2022] Open
Abstract
All Chlamydia species are obligate intracellular bacteria that undergo a unique biphasic developmental cycle strictly in the lumen of a membrane bound compartment, the inclusion. Chlamydia specific Type III secreted effectors, known as inclusion membrane proteins (Inc), are embedded into the inclusion membrane. Progression through the developmental cycle, in particular early events of conversion from infectious (EB) to replicative (RB) bacteria, is important for intracellular replication, but poorly understood. Here, we identified the inclusion membrane protein IncS as a critical factor for Chlamydia development. We show that a C. trachomatis conditional mutant is impaired in transition from EB to RB in human cells, and C. muridarum mutant bacteria fail to develop in a mouse model of Chlamydia infection. Thus, IncS represents a promising target for therapeutic intervention of the leading cause of sexually transmitted infections of bacterial origin.
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Affiliation(s)
- María Eugenia Cortina
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - R. Clayton Bishop
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - Brittany A. DeVasure
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Isabelle Derré
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
- * E-mail:
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A primary Chlamydia trachomatis genital infection of rhesus macaques identifies new immunodominant B-cell antigens. PLoS One 2021; 16:e0250317. [PMID: 33886668 PMCID: PMC8061917 DOI: 10.1371/journal.pone.0250317] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/05/2021] [Indexed: 01/09/2023] Open
Abstract
To identify immunodominant antigens that elicit a humoral immune response following a primary and a secondary genital infection, rhesus monkeys were inoculated cervically with Chlamydia trachomatis serovar D. Serum samples were collected and probed with a protein microarray expressing 864/894 (96.4%) of the open reading frames of the C. trachomatis serovar D genome. The antibody response to the primary infection was analyzed in 72 serum samples from 12 inoculated monkeys. The following criteria were utilized to identify immunodominant antigens: proteins found to be recognized by at least 75% (9/12) of the infected monkeys with at least 15% elevations in signal intensity from week 0 to week 8 post infection. All infected monkeys developed Chlamydia specific serum antibodies. Eight proteins satisfied the selection criteria for immunodominant antigens: CT242 (OmpH-like protein), CT541 (mip), CT681 (ompA), CT381 (artJ), CT443 (omcB), CT119 (incA), CT486 (fliY), and CT110 (groEL). Of these, three antigens, CT119, CT486 and CT381, were not previously identified as immunodominant antigens using non-human primate sera. Following the secondary infection, the antibody responses to the eight immunodominant antigens were analyzed and found to be quite different in intensity and duration to the primary infection. In conclusion, these eight immunodominant antigens can now be tested for their ability to identify individuals with a primary C. trachomatis genital infection and to design vaccine strategies to protect against a primary infection with this pathogen.
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Lu C, Sun Z, Chen H, Chen L, Zhu C, Chen C, Li C, Peng B, Zhong G. Proteome array of antibody responses to Chlamydia trachomatis infection in nonhuman primates. Life Sci 2020; 248:117444. [PMID: 32084433 DOI: 10.1016/j.lfs.2020.117444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 02/09/2020] [Accepted: 02/17/2020] [Indexed: 11/29/2022]
Abstract
AIMS Nonhuman primates have been used to investigate pathogenic mechanisms and evaluate immune responses following Chlamydia trachomatis inoculation. This study aimed to systemically profile antibody responses to C. trachomatis infection in nonhuman primates. MATERIALS AND METHODS Sera were obtained from 4 pig-tailed and 8 long-tailed macaques which were intravaginally or ocularly infected with live C. trachomatis organisms, and analyzed by C. trachomatis proteome array of antigens. KEY FINDINGS The sera from 12 macaques recognized total 172 C. trachomatis antigens. While 84 antigens were recognized by pig-tailed macaques intravaginally infected with serovar D strain, 125 antigens were recognized by long-tailed macaques ocularly infected with serovar A, and 37 antigens were recognized by both. Ocular inoculation with virulent A2497 strain induced antibodies to more antigens. Among the antigens uniquely recognized by A2497 strain infected macaques, outer membrane complex B antigen (OmcB) induced robust antibody response. Although macaques infected by less virulent A/HAR-13 strain failed to develop antibodies to OmcB, reinfection by A2497 strain induced high levels of antibodies to OmcB. SIGNIFICANCE Proteome array has revealed a correlation of chlamydial infection invasiveness with chlamydial antigen immunogenicity, and identified antibody responses to OmcB potentially as biomarkers for invasive infection with C. trachomatis.
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Affiliation(s)
- Chunxue Lu
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan 421001, China
| | - Zhenjie Sun
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan 421001, China
| | - Hui Chen
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan 421001, China
| | - Lili Chen
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan 421001, China
| | - Cuiming Zhu
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan 421001, China
| | - Chaoqun Chen
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan 421001, China
| | - Changqing Li
- Nanyue Biopharmaceutical Co. Ltd., Hunan Province Innovative Training Base for Postgraduates, University of South China and Nanyue Biopharmaceutical Co. Ltd., Hengyang, Hunan 421001, China
| | - Bo Peng
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan 421001, China; Department of Pathology, Hengyang Medical College, University of South China, Hengyang, Hunan 421001, China.
| | - Guangming Zhong
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
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Bugalhão JN, Mota LJ. The multiple functions of the numerous Chlamydia trachomatis secreted proteins: the tip of the iceberg. MICROBIAL CELL 2019; 6:414-449. [PMID: 31528632 PMCID: PMC6717882 DOI: 10.15698/mic2019.09.691] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Chlamydia trachomatis serovars are obligate intracellular bacterial pathogens mainly causing ocular and urogenital infections that affect millions of people worldwide and which can lead to blindness or sterility. They reside and multiply intracellularly within a membrane-bound vacuolar compartment, known as inclusion, and are characterized by a developmental cycle involving two morphologically and physiologically distinct chlamydial forms. Completion of the developmental cycle involves the secretion of > 70 C. trachomatis proteins that function in the host cell cytoplasm and nucleus, in the inclusion membrane and lumen, and in the extracellular milieu. These proteins can, for example, interfere with the host cell cytoskeleton, vesicular and non-vesicular transport, metabolism, and immune signalling. Generally, this promotes C. trachomatis invasion into, and escape from, host cells, the acquisition of nutrients by the chlamydiae, and evasion of cell-autonomous, humoral and cellular innate immunity. Here, we present an in-depth review on the current knowledge and outstanding questions about these C. trachomatis secreted proteins.
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Affiliation(s)
- Joana N Bugalhão
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Luís Jaime Mota
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
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Hypothetical protein Cpn0423 triggers NOD2 activation and contributes to Chlamydia pneumoniae-mediated inflammation. BMC Microbiol 2017; 17:153. [PMID: 28693414 PMCID: PMC5504769 DOI: 10.1186/s12866-017-1062-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 06/29/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chlamydia pneumoniae (C. pneumoniae) is pathogenic to humans, by causing pulmonary inflammation or bronchitis in both adolescents and young adults. However, the molecular signals linking C. pneumoniae components to inflammation remain elusive. This study was to investigate the effect of Chlamydia-specific Cpn0423 of C. pneumoniae on C. pneumoniae-mediated inflammation. RESULTS Cpn0423 was detected outside of C. pneumoniae inclusions, which induced production of several cytokines including macrophage inflammatory protein-2 (MIP-2) and interleukins (ILs). Production of the Cpn0423-induced cytokines was markedly reduced in cells pretreated with NOD2-siRNA, but not with negative control oligonucleotides. Mice treated with Cpn0423 through intranasal administration exhibited pulmonary inflammation as evidenced by infiltration of inflammatory cells, increased inflammatory scores in the lung histology, recruitment of neutrophils and increased cytokines levels in the BALF. CONCLUSION Cpn0423 could be sensed by NOD2, which was identified as an essential element in a pathway contributing to the development of C. pneumoniae -mediated inflammation.
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Update on Chlamydia trachomatis Vaccinology. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00543-16. [PMID: 28228394 DOI: 10.1128/cvi.00543-16] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Attempts to produce a vaccine to protect against Chlamydia trachomatis-induced trachoma were initiated more than 100 years ago and continued for several decades. Using whole organisms, protective responses were obtained. However, upon exposure to C. trachomatis, disease exacerbation developed in some immunized individuals, precluding the implementation of the vaccine. Evidence of the role of C. trachomatis as a sexually transmitted pathogen started to emerge in the 1960s, and it soon became evident that it can cause acute infections and long-term sequelae in women, men, and newborns. The main focus of this minireview is to summarize recent findings and discuss formulations, including antigens, adjuvants, routes, and delivery systems for immunization, primarily explored in the female mouse model, with the goal of implementing a vaccine against C. trachomatis genital infections.
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Pickering H, Burr SE, Derrick T, Makalo P, Joof H, Hayward RD, Holland MJ. Profiling and validation of individual and patterns of Chlamydia trachomatis-specific antibody responses in trachomatous trichiasis. Parasit Vectors 2017; 10:143. [PMID: 28288672 PMCID: PMC5347170 DOI: 10.1186/s13071-017-2078-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 03/06/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ocular Chlamydia trachomatis (Ct) infection causes trachoma, the leading infectious cause of blindness. A Ct D/UW3 proteome microarray and sera from Gambian adults with trachomatous trichiasis (TT) or healthy matched controls previously identified several novel antigens, which suggested differential recognition in adults with TT. METHODS We re-analysed this serological microarray data using more robust microarray analysis techniques accounting for typical problems associated with highly dimensional data. We examined the Ct-specific antibody profile concerning the overall diversity of responses, antigen expression stage and cellular localisation of antigens. We tested differentially recognised antigens by further serological testing of the screened sera and used larger independent sample sets for validation. RESULTS Antibody responses identified High-Performance on antigens expressed early and late in the Ct developmental cycle and those secreted or localised to the outer membrane. Eight antigens were preferentially recognised by scarred individuals and one antigen by healthy individuals. Three of these antigens, two associated with scarring (CT667 and CT706) and one healthy-associated (CT442), were not associated with the presence or absence of scarring following specific serological testing of the arrayed sera and sera from larger, independent case-control cohorts. CONCLUSIONS This study identified focussed Ct-specific antibody profiles targeting proteins expressed during entry and exit from cells and localised to interact with the host. A small panel of antibody responses could discriminate between adults with and without TT in a trachoma-endemic community. Heterogenous responses in the independent validation of these antibody targets highlighted the need for large sample sizes, clearly defined clinical phenotypes and follow-up work.
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Affiliation(s)
- Harry Pickering
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK.
| | - Sarah E Burr
- Disease Control and Elimination Theme, Medical Research Council, The Gambia Unit, Fajara, Banjul, Gambia
| | - Tamsyn Derrick
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Pateh Makalo
- Disease Control and Elimination Theme, Medical Research Council, The Gambia Unit, Fajara, Banjul, Gambia
| | - Hassan Joof
- Disease Control and Elimination Theme, Medical Research Council, The Gambia Unit, Fajara, Banjul, Gambia
| | - Richard D Hayward
- Institute of Structural and Molecular Biology, Birkbeck and University College London, Malet Street, London, UK
| | - Martin J Holland
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
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Wali S, Gupta R, Yu JJ, Lanka GKK, Chambers JP, Guentzel MN, Zhong G, Murthy AK, Arulanandam BP. Chlamydial protease-like activity factor mediated protection against C. trachomatis in guinea pigs. Immunol Cell Biol 2016; 95:454-460. [PMID: 27990018 PMCID: PMC5449249 DOI: 10.1038/icb.2016.122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 12/02/2016] [Accepted: 12/06/2016] [Indexed: 01/30/2023]
Abstract
We have comprehensively demonstrated using the mouse model that intranasal immunization with recombinant chlamydial protease-like activity factor (rCPAF) leads to a significant reduction in bacterial burden, genital tract pathology and preserves fertility following intravaginal genital chlamydial challenge. In the present report, we evaluated the protective efficacy of rCPAF immunization in guinea pigs, a second animal model for genital chlamydial infection. Using a vaccination strategy similar to the mouse model, we intranasally immunized female guinea pigs with rCPAF plus CpG deoxynucleotides (CpG; as an adjuvant), and challenged intravaginally with C. trachomatis serovar D (CT-D). Immunization with rCPAF/CpG significantly reduced vaginal CT-D shedding and induced resolution of infection by day 24, compared to day 33 in CpG alone treated and challenged animals. Immunization induced robust anti-rCPAF serum IgG 2 weeks following the last immunization, and was sustained at a high level 4 weeks post challenge. Upregulation of antigen specific IFN-γ gene expression was observed in rCPAF/CpG vaccinated splenocytes. Importantly, a significant reduction in inflammation in the genital tissue in rCPAF/CpG-immunized guinea pigs compared to CpG-immunized animals was observed. Taken together, this study provides evidence of the protective efficacy of rCPAF as a vaccine candidate in a second animal model of genital chlamydial infection.
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Affiliation(s)
- Shradha Wali
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Rishein Gupta
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Jieh-Juen Yu
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Gopala Krishna Koundinya Lanka
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - James P Chambers
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - M Neal Guentzel
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Ashlesh K Murthy
- Department of Pathology, Midwestern University, Downers Grove, IL, USA
| | - Bernard P Arulanandam
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
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Mueller KE, Fields KA. Application of β-lactamase reporter fusions as an indicator of effector protein secretion during infections with the obligate intracellular pathogen Chlamydia trachomatis. PLoS One 2015; 10:e0135295. [PMID: 26258949 PMCID: PMC4530969 DOI: 10.1371/journal.pone.0135295] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/20/2015] [Indexed: 02/05/2023] Open
Abstract
Chlamydia spp. utilize multiple secretion systems, including the type III secretion system (T3SS), to deploy host-interactive effector proteins into infected host cells. Elucidation of secreted proteins has traditionally required ectopic expression in a surrogate T3SS followed by immunolocalization of endogenous candidate effectors to confirm secretion by chlamydiae. The ability to transform Chlamydia and achieve stable expression of recombinant gene products has enabled a more direct assessment of secretion. We adapted TEM-1 β-lactamase as a reporter system for assessment of chlamydial protein secretion. We provide evidence that this system facilitates visualization of secretion in the context of infection. Specifically, our findings provide definitive evidence that C. trachomatis CT695 is secreted during infection. Follow-up indirect immunofluorescence studies confirmed CT695 secretion and indicate that this effector can be secreted at multiple points during the chlamydial developmental cycle. Our results indicate that the BlaM-fusion reporter assay will allow efficacious identification of novel secreted proteins. Moreover, this approach can easily be adapted to enable more sophisticated studies of the secretion process in Chlamydia.
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Affiliation(s)
- Konrad E. Mueller
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States of America
| | - Kenneth A. Fields
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States of America
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The Chlamydia pneumoniae Inclusion Membrane Protein Cpn1027 Interacts with Host Cell Wnt Signaling Pathway Regulator Cytoplasmic Activation/Proliferation-Associated Protein 2 (Caprin2). PLoS One 2015; 10:e0127909. [PMID: 25996495 PMCID: PMC4440618 DOI: 10.1371/journal.pone.0127909] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 04/21/2015] [Indexed: 11/19/2022] Open
Abstract
We previously identified hypothetical protein Cpn1027 as a novel inclusion membrane protein that is unique to Chlamydia pneumoniae. In the current study, using a yeast-two hybrid screen assay, we identified host cell cytoplasmic activation/proliferation-associated protein 2 (Caprin2) as an interacting partner of Cpn1027. The interaction was confirmed and mapped to the C-termini of both Cpn1027 and Caprin2 using co-immunoprecipitation and GST pull-down assays. A RFP-Caprin2 fusion protein was recruited to the chlamydial inclusion and so was the endogenous GSK3β, a critical component of the β-catenin destruction complex in the Wnt signaling pathway. Cpn1027 also co-precipitated GSK3β. Caprin2 is a key regulator of the Wnt signaling pathway by promoting the recruitment of the β-catenin destruction complex to the cytoplasmic membrane in the presence of Wnt signaling while GSK3β is required for priming β-catenin for degradation in the absence of Wnt signaling. The Cpn1027 interactions with Caprin2 and GSK3β may allow C. pneumoniae to actively sequester the β-catenin destruction complex so that β-catenin is maintained even in the absence of extracellular Wnt activation signals. The maintained β-catenin can trans-activate Wnt target genes including Bcl-2, which may contribute to the chlamydial antiapoptotic activity. We found that the C. pneumoniae-infected cells were more resistant to apoptosis induction and the anti-apoptotic activity was dependent on β-catenin. Thus, the current study suggests that the chlamydial inclusion protein Cpn1027 may be able to manipulate host Wnt signaling pathway for enhancing the chlamydial anti-apoptotic activity.
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Borges V, Gomes JP. Deep comparative genomics among Chlamydia trachomatis lymphogranuloma venereum isolates highlights genes potentially involved in pathoadaptation. INFECTION GENETICS AND EVOLUTION 2015; 32:74-88. [PMID: 25745888 DOI: 10.1016/j.meegid.2015.02.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/23/2015] [Accepted: 02/26/2015] [Indexed: 11/19/2022]
Abstract
Lymphogranuloma venereum (LGV) is a human sexually transmitted disease caused by the obligate intracellular bacterium Chlamydia trachomatis (serovars L1-L3). LGV clinical manifestations range from severe ulcerative proctitis (anorectal syndrome), primarily caused by the epidemic L2b strains, to painful inguinal lymphadenopathy (the typical LGV bubonic form). Besides potential host-related factors, the differential disease severity and tissue tropism among LGV strains is likely a function of the genetic backbone of the strains. We aimed to characterize the genetic variability among LGV strains as strain- or serovar-specific mutations may underlie phenotypic signatures, and to investigate the mutational events that occurred throughout the pathoadaptation of the epidemic L2b lineage. By analyzing 20 previously published genomes from L1, L2, L2b and L3 strains and two new genomes from L2b strains, we detected 1497 variant sites and about 100 indels, affecting 453 genes and 144 intergenic regions, with 34 genes displaying a clear overrepresentation of nonsynonymous mutations. Effectors and/or type III secretion substrates (almost all of those described in the literature) and inclusion membrane proteins showed amino acid changes that were about fivefold more frequent than silent changes. More than 120 variant sites occurred in plasmid-regulated virulence genes, and 66% yielded amino acid changes. The identified serovar-specific variant sites revealed that the L2b-specific mutations are likely associated with higher fitness and pointed out potential targets for future highly discriminatory diagnostic/typing tests. By evaluating the evolutionary pathway beyond the L2b clonal radiation, we observed that 90.2% of the intra-L2b variant sites occurring in coding regions involve nonsynonymous mutations, where CT456/tarp has been the main target. Considering the progress on C. trachomatis genetic manipulation, this study may constitute an important contribution for prioritizing study targets for functional genomics aiming to dissect the impact of the identified intra-LGV polymorphisms on virulence or tropism dissimilarities among LGV strains.
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Affiliation(s)
- Vítor Borges
- Reference Laboratory of Bacterial Sexually Transmitted Infections, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal; Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal
| | - João Paulo Gomes
- Reference Laboratory of Bacterial Sexually Transmitted Infections, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal; Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal.
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Seroprevalence of antibodies against Pkn1, a novel potential immunogen, in Chlamydia trachomatis-infected Macaca nemestrina and human patients. BIOMED RESEARCH INTERNATIONAL 2014; 2014:245483. [PMID: 25032212 PMCID: PMC4086347 DOI: 10.1155/2014/245483] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/24/2014] [Indexed: 11/17/2022]
Abstract
Chlamydia trachomatis (CT) is an important cause of sexually transmitted genital tract infections (STIs) and trachoma. Despite major research into chlamydial pathogenesis and host immune responses, immunoprotection has been hampered by the incomplete understanding of protective immunity in the genital tract. Characterized vaccine candidates have shown variable efficacy ranging from no protection to partial protection in vivo. It is therefore a research priority to identify novel chlamydial antigens that may elicit protective immune responses against CT infection. In the present study we assessed the seroprevalence of antibodies against protein kinase1 (Pkn1), DNA ligaseA (LigA), and major outer membrane protein A (OmpA) following natural CT infection in humans and in experimentally induced CT infection in Macaca nemestrina. Antigenic stretches of Pkn1, LigA, and OmpA were identified using bioinformatic tools. Pkn1, LigA, and OmpA genes were cloned in bacterial expression vector and purified by affinity chromatography. Our results demonstrate significantly high seroprevalence of antibodies against purified Pkn1 and OmpA in sera obtained from the macaque animal model and human patients infected with CT. In contrast no significant seroreactivity was observed for LigA. The seroprevalence of antibodies against Pkn1 suggest that nonsurface chlamydial proteins could also be important for developing vaccines for C. trachomatis.
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A Conrad T, Yang Z, Ojcius D, Zhong G. A path forward for the chlamydial virulence factor CPAF. Microbes Infect 2013; 15:1026-32. [PMID: 24141088 DOI: 10.1016/j.micinf.2013.09.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 08/26/2013] [Accepted: 09/02/2013] [Indexed: 12/14/2022]
Abstract
CPAF is a conserved and secreted protease from obligate intracellular bacteria of the order Chlamydiales. Recently, it was demonstrated that most of its host targets are an artifact of inaccurate methods. This review aims to summarize key features of CPAF and propose new approaches for evaluating its role in chlamydial pathogenesis.
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Affiliation(s)
- Turner A Conrad
- Department of Microbiology and Immunology, University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
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17
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Lu C, Lei L, Peng B, Tang L, Ding H, Gong S, Li Z, Wu Y, Zhong G. Chlamydia trachomatis GlgA is secreted into host cell cytoplasm. PLoS One 2013; 8:e68764. [PMID: 23894341 PMCID: PMC3722199 DOI: 10.1371/journal.pone.0068764] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 06/04/2013] [Indexed: 12/03/2022] Open
Abstract
Glycogen has been localized both inside and outside Chlamydia trachomatis organisms. We now report that C. trachomatis glycogen synthase (GlgA) was detected in both chlamydial organism-associated and -free forms. The organism-free GlgA molecules were localized both in the lumen of chlamydial inclusions and in the cytosol of host cells. The cytosolic GlgA displayed a distribution pattern similar to that of a known C. trachomatis-secreted protease, CPAF. The detection of GlgA was specific since the anti-GlgA antibody labeling was only removed by preabsorption with GlgA but not CPAF fusion proteins. GlgA was detectable at 12h and its localization into host cell cytosol only became apparent at 24h after infection. The cytosolic localization of GlgA was conserved among all C. trachomatis serovars. However, the significance of the GlgA secretion into host cell cytoplasm remains unclear since, while expression of chlamydial GlgA in HeLa cells increased glycogen stores, it did not affect a subsequent infection with C. trachomatis. Similar to several other C. trachomatis-secreted proteins, GlgA is immunogenic in women urogenitally infected with C. trachomatis, suggesting that GlgA is expressed and may be secreted into host cell cytosol during C. trachomatis infection in humans. These findings have provided important information for further understanding C. trachomatis pathogenic mechanisms.
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Affiliation(s)
- Chunxue Lu
- Department of Pathogen Biology, University of South China, Hengyang, Hunan, China
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Lei Lei
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Bo Peng
- Department of Pathogen Biology, University of South China, Hengyang, Hunan, China
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Lingli Tang
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Honglei Ding
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Siqi Gong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Zhongyu Li
- Department of Pathogen Biology, University of South China, Hengyang, Hunan, China
| | - Yimou Wu
- Department of Pathogen Biology, University of South China, Hengyang, Hunan, China
- * E-mail: (YW); (GZ)
| | - Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- * E-mail: (YW); (GZ)
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Arpaci T, Ugurluer G, Akbas T, Arpaci RB, Serin M. Imaging of the skeletal muscle metastases. EUROPEAN REVIEW FOR MEDICAL AND PHARMACOLOGICAL SCIENCES 2013. [PMID: 23280019 PMCID: PMC7163697 DOI: 10.1002/ddr.21049] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Copyright 2011 Wiley-Liss, Inc., A Wiley CompanyThis article is being made freely available through PubMed Central as part of the COVID-19 public health emergency response. It can be used for unrestricted research re-use and analysis in any form or by any means with acknowledgement of the original source, for the duration of the public health emergency. Omics technologies include genomics, transcriptomics, proteomics, metabolomics, and immunomics. These technologies have been used in vaccine research, which can be summarized using the term “vaccinomics.” These omics technologies combined with advanced bioinformatics analysis form the core of “systems vaccinology.” Omics technologies provide powerful methods in vaccine target identification. The genomics‐based reverse vaccinology starts with predicting vaccine protein candidates through in silico bioinformatics analysis of genome sequences. The VIOLIN Vaxign vaccine design program (http://www.violinet.org/vaxign) is the first web‐based vaccine target prediction software based on the reverse vaccinology strategy. Systematic transcriptomics and proteomics analyses facilitate rational vaccine target identification by detesting genome‐wide gene expression profiles. Immunomics is the study of the set of antigens recognized by host immune systems and has also been used for efficient vaccine target prediction. With the large amount of omics data available, it is necessary to integrate various vaccine data using ontologies, including the Gene Ontology (GO) and Vaccine Ontology (VO), for more efficient vaccine target prediction and assessment. All these omics technologies combined with advanced bioinformatics analysis methods for a systems biology‐based vaccine target prediction strategy. This article reviews the various omics technologies and how they can be used in vaccine target identification.
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Affiliation(s)
- T Arpaci
- Department of Radiology, Acibadem Adana Hospital, Adana, Turkey.
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Wang X, Xiong X, Graves S, Stenos J, Wen B. Protein array of Coxiella burnetii probed with Q fever sera. SCIENCE CHINA-LIFE SCIENCES 2013; 56:453-9. [PMID: 23633077 DOI: 10.1007/s11427-013-4472-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 03/21/2013] [Indexed: 10/26/2022]
Abstract
Coxiella burnetii is the etiological agent of Q fever. To identify its major seroreactive proteins, a subgenomic protein array was developed. A total of 101 assumed virulence-associated recombinant proteins of C. burnetii were probed with sera from mice experimentally infected with C. burnetii and sera from Q fever patients. Sixteen proteins were recognized as major seroreactive antigens by the mouse sera. Seven of these 16 proteins reacted positively with at least 45% of Q fever patient sera. Notably, HspB had the highest fluorescence intensity value and positive frequency of all the proteins on the array when probed with both Q fever patient sera and mouse sera. These results suggest that these seven major seroreactive proteins, particularly HspB, are potential serodiagnostic and subunit vaccine antigens of Q fever.
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Affiliation(s)
- Xile Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
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Chlamydia trachomatis outer membrane complex protein B (OmcB) is processed by the protease CPAF. J Bacteriol 2012; 195:951-7. [PMID: 23222729 DOI: 10.1128/jb.02087-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We previously reported that the Chlamydia trachomatis outer membrane complex protein B (OmcB) was partially processed in Chlamydia-infected cells. We have now confirmed that the OmcB processing occurred inside live cells during chlamydial infection and was not due to proteolysis during sample harvesting. OmcB processing was preceded by the generation of active CPAF, a serine protease known to be able to cross the inner membrane via a Sec-dependent pathway, suggesting that active CPAF is available for processing OmcB in the periplasm. In a cell-free system, CPAF activity is both necessary and sufficient for processing OmcB. Both depletion of CPAF from Chlamydia-infected cell lysates with a CPAF-specific antibody and blocking CPAF activity with a CPAF-specific inhibitory peptide removed the OmcB processing ability of the lysates. A highly purified wild-type CPAF but not a catalytic residue-substituted mutant CPAF was sufficient for processing OmcB. Most importantly, in chlamydial culture, inhibition of CPAF with a specific inhibitory peptide blocked OmcB processing and reduced the recovery of infectious organisms. Thus, we have identified OmcB as a novel authentic target for the putative chlamydial virulence factor CPAF, which should facilitate our understanding of the roles of CPAF in chlamydial biology and pathogenesis.
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Yeh HY, Klesius PH. Construction, expression and characterization of 11 putative flagellar apparatus genes of Aeromonas hydrophila AL09-73. JOURNAL OF FISH DISEASES 2012; 35:853-860. [PMID: 22924657 DOI: 10.1111/j.1365-2761.2012.01438.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 08/27/2011] [Accepted: 09/05/2011] [Indexed: 06/01/2023]
Affiliation(s)
- H-Y Yeh
- Aquatic Animal Health Research Unit, Agricultural Research Service, United States Department of Agriculture, Auburn, AL, USA.
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Directional evolution of Chlamydia trachomatis towards niche-specific adaptation. J Bacteriol 2012; 194:6143-53. [PMID: 22961851 DOI: 10.1128/jb.01291-12] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
On behalf of the host-pathogen "arms race," a cutting-edge approach for elucidating genotype-phenotype relationships relies on the identification of positively selected loci involved in pathoadaptation. We studied the obligate intracellular bacterium Chlamydia trachomatis, for which same-species strains display a nearly identical core and pan genome, while presenting a wide range of tissue tropism and ecological success. We sought to evaluate the evolutionary patterns underlying species separation (divergence) and C. trachomatis serovar radiation (polymorphism) and to establish genotype-phenotype associations. By analyzing 60 Chlamydia strains, we detected traces of Muller's ratchet as a result of speciation and identified positively selected genes and codons hypothetically involved in the infection of different human cell types (e.g., columnar epithelial cells of ocular or genital mucosae and mononuclear phagocytes) and also events likely driving pathogenic and ecological success dissimilarities. In general, these genes code for proteins involved in immune response elicitation, proteolysis, and the subversion of host-cell functions, and also for proteins with unknown function(s). Several genes are potentially involved in more than one adaptive process, suggesting multiple functions or a distinct modus operandi for a specific function, and thus should be considered as crucial research targets. In addition, six of the nine genes encoding the putative antigen/adhesin polymorphic membrane proteins seem to be under positive selection along specific serovars, which sustains an essential biological role of this extra-large paralogue family in chlamydial pathobiology. This study provides insight into how evolutionary inferences illuminate ecological processes such as adaptation to different niches, pathogenicity, or ecological success driven by arms races.
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Childs TS, Webley WC. In vitro assessment of halobacterial gas vesicles as a Chlamydia vaccine display and delivery system. Vaccine 2012; 30:5942-8. [DOI: 10.1016/j.vaccine.2012.07.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Revised: 06/06/2012] [Accepted: 07/18/2012] [Indexed: 12/30/2022]
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Proteomic identification of immunodominant chlamydial antigens in a mouse model. J Proteomics 2012; 77:176-86. [PMID: 22959960 DOI: 10.1016/j.jprot.2012.08.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 08/04/2012] [Accepted: 08/23/2012] [Indexed: 11/20/2022]
Abstract
Chlamydia trachomatis is the most common bacterial sexually transmitted pathogen in the world. To identify new vaccine candidates a protein microarray was constructed by expressing the open reading frames (ORFs) from Chlamydia mouse pneumonitis (MoPn). C57BL/6, C3H/HeN and BALB/c mice were immunized either intranasally or intravaginally with live MoPn elementary bodies (EB). Two additional groups were immunized by the intramuscular plus subcutaneous routes with UV-treated EB, using CpG and Montanide as adjuvants to favor a Th1 response, or Alum, to elicit a Th2 response. Serum samples collected from the three strains of mice were tested in the microarray. The array included the expression of 909 proteins from the 921 ORFs of the MoPn genome and plasmid. A total of 530 ORFs were recognized by at least one serum sample. Of these, 36 reacted with sera from the three strains of mice immunized with live EB. These antigens included proteins that were previously described as immunogenic such as MOMP and HSP60. In addition, we uncovered new immunogens, including 11 hypothetical proteins. In summary, we have identified new immunodominant chlamydial proteins that can be tested for their ability to induce protection in animal models and subsequently in humans.
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Chlamydia trachomatis antigens recognized in women with tubal factor infertility, normal fertility, and acute infection. Obstet Gynecol 2012; 119:1009-16. [PMID: 22525912 DOI: 10.1097/aog.0b013e3182519326] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
OBJECTIVE To identify Chlamydia trachomatis antigens associated with tubal factor infertility and acute infection. METHODS A C trachomatis proteome array was used to compare antibody profiles among women with tubal factor infertility, normal fertility, and acute C trachomatis infection. RESULTS Thirteen immunodominant antigens reacted with 50% or more sera from all women (n=73). Six C trachomatis antigens were uniquely recognized in women with tubal factor infertility. Combining fragmentation of the six antigens with serum sample dilution, chlamydial antigens HSP60, CT376, CT557, and CT443 could discriminate between women with tubal factor infertility and women with normal fertility with a sensitivity of 63% (95% confidence interval [CI] 0.41-0.77) and specificity of 100% (95% CI 0.91-1), respectively. These antigens were designated as tubal factor infertility-associated antigens. However, these tubal factor antigens were unable to distinguish tubal factor infertility patients from those with acute infection. A combination of CT875 and CT147 distinguished women with acute infection from all other C trachomatis-exposed women with a detection sensitivity of 63% (95% CI 0.41-0.77) and specificity of 100% (95% CI 0.95-1), respectively. Thus, CT875 and CT147 were designated as acute infection-associated antigens. CONCLUSION A sequential screening of antibodies against panels of C trachomatis antigens can be used to identify women with tubal factor infertility and acute C trachomatis infection. LEVEL OF EVIDENCE II.
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Lu C, Holland MJ, Gong S, Peng B, Bailey RL, Mabey DW, Wu Y, Zhong G. Genome-wide identification of Chlamydia trachomatis antigens associated with trachomatous trichiasis. Invest Ophthalmol Vis Sci 2012; 53:2551-9. [PMID: 22427578 DOI: 10.1167/iovs.11-9212] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Chlamydia trachomatis is the leading infectious cause of blindness. The goal of the current study was to search for biomarkers associated with C. trachomatis-induced ocular pathologies. METHODS We used a whole genome scale proteome array to systematically profile antigen specificities of antibody responses to C. trachomatis infection in individuals from trachoma-endemic communities with or without end-stage trachoma (trichiasis) in The Gambia. RESULTS When 61 trichiasis patients were compared with their control counterparts for overall antibody reactivity with organisms of different chlamydial species, no statistically significant difference was found. Both groups developed significantly higher titers of antibodies against C. trachomatis ocular serovars A and B than ocular serovar C, genital serovar D, or Chlamydia psittaci, whereas the titers of anti-Chlamydia pneumoniae antibodies were the highest. When antisera from 33 trichiasis and 26 control patients (with relatively high titers of antibodies to C. trachomatis ocular serovars) were reacted with 908 C. trachomatis proteins, 447 antigens were recognized by at least 1 of the 59 antisera, and 10 antigens by 50% or more antisera, the latter being designated as immunodominant antigens. More importantly, four antigens were preferentially recognized by the trichiasis group, with antigens CT414, CT667, and CT706 collectively reacting with 30% of trichiasis antisera but none from the normal group, and antigen CT695 reacting with 61% of trichiasis but only 31% of normal antisera. On the other hand, eight antigens were preferentially recognized by the control group, with antigens CT019, CT117, CT301, CT553, CT556, CT571, and CT709 together reacting with 46% of normal antisera and none from the trichiasis group, whereas antigen CT442 reacted with 35% of normal and 19% of trichiasis antisera respectively. CONCLUSIONS The current study, by mapping immunodominant C. trachomatis antigens and identifying antigens associated with both ocular pathology and protection, has provided important information for further understanding chlamydial pathogenesis and the development of subunit vaccines.
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Affiliation(s)
- Chunxue Lu
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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Mapping immunodominant antigens and H-2-linked antibody responses in mice urogenitally infected with Chlamydia muridarum. Microbes Infect 2012; 14:659-65. [PMID: 22421110 DOI: 10.1016/j.micinf.2012.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 02/14/2012] [Accepted: 02/15/2012] [Indexed: 01/07/2023]
Abstract
To identify immunodominant antigens and MHC-restricted antibody responses, seven different strains of mice were intravaginally infected with Chlamydia muridarum and compared for antibody responses to 257 C. muridarum proteins. The 7 strains of mice recognized a total of 109 proteins as antigens, of which, 5 antigens (TC0660, TC0727, TC0828, TC0726 & TC0268) were each recognized by 60% or more mice from each mouse strain and thus designated as immunodominant antigens. Furthermore, antibody responses to 19 other antigens displayed strong associations with mouse H-2 haplotypes, including 6 antigens (TC0480, TC0912, TC0229, TCA04, TC0289 & TC0892) whose antibody responses were linked to H-2(b), 8 (TC0035, TC0387, TC0052, TC0781, TC0373, TC0117, TC0066 & TC0396) to H-2(d) and 5 (TC0512, TC0177, TC0589, TC0794 & TC0596) to H-2(k) haplotypes respectively. Interestingly, H-2(b) was negatively associated with antibody responses to most of the antigens that were positively linked to H-2(d) or H-2(k) haplotypes. These results by mapping Chlamydia trachomatis antigens commonly recognized by mice with different strain background and H-2 genes and revealing antigen association with H-2 haplotypes have provided important information for developing chlamydial subunit vaccines and understanding chlamydial pathogenesis.
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Li Z, Lu C, Peng B, Zeng H, Zhou Z, Wu Y, Zhong G. Induction of protective immunity against Chlamydia muridarum intravaginal infection with a chlamydial glycogen phosphorylase. PLoS One 2012; 7:e32997. [PMID: 22427926 PMCID: PMC3299733 DOI: 10.1371/journal.pone.0032997] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 02/06/2012] [Indexed: 11/19/2022] Open
Abstract
We evaluated 7 C. muridarum ORFs for their ability to induce protection against chlamydial infection in a mouse intravaginal infection model. These antigens, although encoded in C. muridarum genome, are transcriptionally regulated by a cryptic plasmid that is known to contribute to C. muridarum pathogenesis. Of the 7 plasmid-regulated ORFs, the chlamydial glycogen phosphorylase or GlgP, when delivered into mice intramuscularly, induced the most pronounced protective immunity against C. muridarum intravaginal infection. The GlgP-immunized mice displayed a significant reduction in vaginal shedding of live organisms on day 14 after infection. The protection correlated well with a robust C. muridarum-specific antibody and a Th1-dominant T cell responses, which significantly reduced the severity but not overall incidence of hydrosalpinx. The GlgP-induced partial protection against upper genital tract pathology suggests that GlgP may be considered a component for a multi-subunit vaccine. These results have demonstrated that intramuscular immunization of mice with purified proteins can be used to identify vaccine antigens for preventing intravaginal infection with C. trachomatis in humans.
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Affiliation(s)
- Zhihong Li
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Chunxue Lu
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Microbiology and Pathology, University of South China, Hengyang, Hunan, China
| | - Bo Peng
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Microbiology and Pathology, University of South China, Hengyang, Hunan, China
| | - Hao Zeng
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Zhiguan Zhou
- Department of Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yimou Wu
- Department of Microbiology and Pathology, University of South China, Hengyang, Hunan, China
| | - Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- * E-mail:
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Kebbi-Beghdadi C, Lienard J, Uyttebroeck F, Baud D, Riederer BM, Greub G. Identification of immunogenic proteins of Waddlia chondrophila. PLoS One 2012; 7:e28605. [PMID: 22238579 PMCID: PMC3251552 DOI: 10.1371/journal.pone.0028605] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 11/11/2011] [Indexed: 11/20/2022] Open
Abstract
Evidence is growing for a role of Waddlia chondrophila as an agent of adverse pregnancy outcomes in both humans and ruminants. This emerging pathogen, member of the order Chlamydiales, is also implicated in bronchiolitis and lower respiratory tract infections. Until now, the serological diagnosis of W. chondrophila infection has mainly relied on manually intensive tests including micro-immunofluorescence and Western blotting. Thus, there is an urgent need to establish reliable high throughput serological assays. Using a combined genomic and proteomic approach, we detected 57 immunogenic proteins of W. chondrophila, of which 17 were analysed by mass spectrometry. Two novel hypothetical proteins, Wim3 and Wim4, were expressed as recombinant proteins in Escherichia coli, purified and used as antigens in an ELISA test. Both proteins were recognized by sera of rabbits immunized with W. chondrophila as well as by human W. chondrophila positive sera but not by rabbit pre-immune sera nor human W. chondrophila negative sera. These results demonstrated that the approach chosen is suitable to identify immunogenic proteins that can be used to develop a serological test. This latter will be a valuable tool to further clarify the pathogenic potential of W. chondrophila.
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Affiliation(s)
- Carole Kebbi-Beghdadi
- Center for Research on Intracellular Bacteria (CRIB), Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Julia Lienard
- Center for Research on Intracellular Bacteria (CRIB), Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Frederic Uyttebroeck
- Center for Research on Intracellular Bacteria (CRIB), Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - David Baud
- Center for Research on Intracellular Bacteria (CRIB), Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Beat M. Riederer
- Department of Cellular Biology and Morphology, University of Lausanne, Lausanne, Switzerland
- Proteomics Unit, Department of Psychiatric Neurosciences, Cery, Prilly-Lausanne, Switzerland
| | - Gilbert Greub
- Center for Research on Intracellular Bacteria (CRIB), Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
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Identification of antigen-specific antibody responses associated with upper genital tract pathology in mice infected with Chlamydia muridarum. Infect Immun 2011; 80:1098-106. [PMID: 22158739 DOI: 10.1128/iai.05894-11] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Urogenital infection with Chlamydia trachomatis in some women can lead to upper genital tract pathologies, such as hydrosalpinx, potentially affecting fertility. In the current study, 27 of 40 mice intravaginally infected with Chlamydia muridarum developed visible hydrosalpinges in the oviduct while the remaining 13 did not, although all infected mice displayed similar infection time courses. Antisera from the 40 mice recognized 130 out of 257 C. muridarum proteins as antigens and 17 as immunodominant antigens. Importantly, the 27 mice with hydrosalpinges preferentially recognized two C. muridarum proteins (TC0582 and TC0912, designated pathology-associated antigens) while the 13 mice with no hydrosalpinx preferentially recognized 10 proteins (TC0047, TC0117, TC0190, TC0197, TC0257, TC0279, TC0326, TC0630, TC0689, and TC0816, designated nonpathology antigens). The preferential recognition was validated by absorption and independently confirmed in Western blots. The C. trachomatis homolog of TC0912 is encoded by a highly polymorphic gene that is associated with ocular pathogenesis. A fragment of TC0912 was found to improve the differentiation of hydrosalpinx from nonhydrosalpinx mice. TC0582 is a highly conserved ATP synthase, and it may contribute to chlamydial pathogenesis via mechanisms similar to those hypothesized for the highly conserved HSP60. Thus, we have identified chlamydial antigens and epitopes that are associated with either susceptibility or resistance to upper genital tract pathology, which will help us to further understand chlamydial pathogenesis and to develop anti-Chlamydia subunit vaccines.
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Yeh HY, Klesius PH. Over-expression, purification and immune responses to Aeromonas hydrophila AL09-73 flagellar proteins. FISH & SHELLFISH IMMUNOLOGY 2011; 31:1278-1283. [PMID: 21963857 DOI: 10.1016/j.fsi.2011.09.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 09/17/2011] [Accepted: 09/18/2011] [Indexed: 05/31/2023]
Abstract
Aeromonas hydrophila is ubiquitous in aquatic environments worldwide and causes many diseases in fish as well as human. Recent outbreaks of aeromonad diseases in channel catfish prompted us to investigate catfish immune responses during infection of A. hydrophila. In this communication, we report to amplify, over-express, purify and characterize 19 A. hydrophila flagellar proteins. All recombinant proteins were confirmed by nucleotide sequencing of expression plasmids, SDS-PAGE analysis and His tag Western blot of induced proteins. Our preliminary result also showed that the purified recombinant FlgK protein reacted strongly to sera from experimentally infected catfish, suggesting that this protein has potential for a novel target for vaccine development. It is also anticipated that these recombinant proteins will provide us with very useful tools to investigate host immune response to this microorganism.
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Affiliation(s)
- Hung-Yueh Yeh
- United States Department of Agriculture, Agricultural Research Service, Aquatic Animal Health Research Unit, 990 Wire Road, Auburn, AL 36832-4352, USA.
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Lu C, Zeng H, Li Z, Lei L, Yeh IT, Wu Y, Zhong G. Protective immunity against mouse upper genital tract pathology correlates with high IFNγ but low IL-17 T cell and anti-secretion protein antibody responses induced by replicating chlamydial organisms in the airway. Vaccine 2011; 30:475-85. [PMID: 22079265 DOI: 10.1016/j.vaccine.2011.10.059] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 09/20/2011] [Accepted: 10/22/2011] [Indexed: 01/02/2023]
Abstract
To search for optimal immunization conditions for inducing protective immunity against upper genital tract pathologies caused by chlamydial intravaginal infection, we compared protection efficacy in mice immunized intranasally or intramuscularly with live or inactivated Chlamydia muridarum organisms. Mice immunized intranasally with live organisms developed strong protection against both vaginal shedding of infectious organisms and upper genital tract pathologies. The protection correlated with a robust antigen-specific T cell response with high IFNγ but low IL-17. Although a significant level of IL-5 was also detected, these mice maintained an overall Th1-dorminant immunity following immunization and challenge infection. On the contrary, mice immunized intranasally with inactivated organisms or intramuscularly with live or inactivated organisms produced high levels of IL-17 and still developed significant upper genital tract pathologies. High titers of antibodies against chlamydial secretion antigens were detected only in mice immunized intranasally with live organisms but not mice in other groups, suggesting that the intranasally inoculated live organisms were able to undergo replication and immune responses to the chlamydial secretion proteins may contribute to protective immunity. These observations have provided important information on how to develop subunit vaccines for inducing protective immunity against urogenital infection with Chlamydia trachomatis organisms.
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Affiliation(s)
- Chunxue Lu
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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Genome-wide identification of Chlamydia trachomatis antigens associated with tubal factor infertility. Fertil Steril 2011; 96:715-21. [PMID: 21742324 DOI: 10.1016/j.fertnstert.2011.06.021] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Revised: 06/06/2011] [Accepted: 06/08/2011] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To identify Chlamydia trachomatis antigens that can be used to differentially diagnose tubal factor infertility in comparison with previously reported heat shock protein 60. DESIGN In vitro study. SETTING Academic medical center. PATIENT(S) Infertile women with and without tubal pathology diagnosed laparoscopically. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Antibody responses to C. trachomatis in infertile women with or without tubal pathologies using a C. trachomatis genome-wide proteome array. RESULT(S) Comparison of the antibody profiles revealed 30 C. trachomatis antigens that were preferentially recognized in women with tubal factor infertility, with a detection sensitivity and specificity of 80.6% and 56.5%, respectively, 10 of which showed 100% specificity. A combination of CT443 and CT381 antigens yielded the highest detection sensitivity (67.7%) while maintaining 100% specificity. CONCLUSION(S) These findings have demonstrated that antibodies to CT443 and CT381, when used in combination, have higher sensitivity and specificity in predicting tubal factor infertility than other indicators for tubal factor infertility, such as heat shock protein 60 antibodies (35.5%, 100%) or hysterosalpingogram (65%, 83%). Using a panel of C. trachomatis antigens to serologically diagnose tubal factor infertility can save the patients from undertaking expensive and invasive procedures for determining tubal pathology and choosing treatment plans.
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Approach to discover T- and B-cell antigens of intracellular pathogens applied to the design of Chlamydia trachomatis vaccines. Proc Natl Acad Sci U S A 2011; 108:9969-74. [PMID: 21628568 DOI: 10.1073/pnas.1101756108] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Natural immunity against obligate and/or facultative intracellular pathogens is usually mediated by both humoral and cellular immunity. The identification of those antigens stimulating both arms of the immune system is instrumental for vaccine discovery. Although high-throughput technologies have been applied for the discovery of antibody-inducing antigens, few examples of their application for T-cell antigens have been reported. We describe how the compilation of the immunome, here defined as the pool of immunogenic antigens inducing T- and B-cell responses in vivo, can lead to vaccine candidates against Chlamydia trachomatis. We selected 120 C. trachomatis proteins and assessed their immunogenicity using two parallel high-throughput approaches. Protein arrays were generated and screened with sera from C. trachomatis-infected patients to identify antibody-inducing antigens. Splenocytes from C. trachomatis-infected mice were stimulated with 79 proteins, and the frequency of antigen-specific CD4(+)/IFN-γ(+) T cells was analyzed by flow cytometry. We identified 21 antibody-inducing antigens, 16 CD4(+)/IFN-γ(+)-inducing antigens, and five antigens eliciting both types of responses. Assessment of their protective activity in a mouse model of Chlamydia muridarum lung infection led to the identification of seven antigens conferring partial protection when administered with LTK63/CpG adjuvant. Protection was largely the result of cellular immunity as assessed by CD4(+) T-cell depletion. The seven antigens provided robust additive protection when combined in four-antigen combinations. This study paves the way for the development of an effective anti-Chlamydia vaccine and provides a general approach for the discovery of vaccines against other intracellular pathogens.
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Lei L, Qi M, Budrys N, Schenken R, Zhong G. Localization of Chlamydia trachomatis hypothetical protein CT311 in host cell cytoplasm. Microb Pathog 2011; 51:101-9. [PMID: 21605656 DOI: 10.1016/j.micpath.2011.05.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2011] [Revised: 05/02/2011] [Accepted: 05/04/2011] [Indexed: 11/28/2022]
Abstract
The chlamydia-specific hypothetical protein CT311 was detected both inside and outside of the chlamydial inclusions in Chlamydia trachomatis-infected cells. The extra-inclusion CT311 molecules were distributed in the host cell cytoplasm with a pattern similar to that of CPAF, a known Chlamydia-secreted protease. The detection of CT311 was specific since the anti-CT311 antibody labeling was only removed by absorption with CT311 but not CPAF fusion proteins. In addition, both anti-CT311 and anti-CPAF antibodies only detected their corresponding endogenous proteins without cross-reacting with each other or any other antigens in the whole cell lysates of C. trachomatis-infected cells. Although both CT311 and CPAF proteins were first detected 12 h after infection, localization of CT311 into host cell cytosol was delayed until 24 h while CPAF secretion into host cell cytosol was already obvious by 18 h after infection. The host cell cytosolic localization of CT311 was further confirmed in human primary cells. CT311 was predicted to contain an N-terminal secretion signal sequence and the CT311 signal sequence directed secretion of PhoA into bacterial periplasmic region in a heterologous assay system, suggesting that a sec-dependent pathway may play a role in the secretion of CT311 into host cell cytosol. This hypothesis is further supported by the observation that secretion of CT311 in Chlamydia-infected cells was blocked by a C16 compound known to inhibit signal peptidase I. These findings have provided important molecular information for further understanding the C. trachomatis pathogenic mechanisms.
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Affiliation(s)
- Lei Lei
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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The chlamydial periplasmic stress response serine protease cHtrA is secreted into host cell cytosol. BMC Microbiol 2011; 11:87. [PMID: 21527029 PMCID: PMC3107777 DOI: 10.1186/1471-2180-11-87] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Accepted: 04/28/2011] [Indexed: 01/05/2023] Open
Abstract
Background The periplasmic High Temperature Requirement protein A (HtrA) plays important roles in bacterial protein folding and stress responses. However, the role of chlamydial HtrA (cHtrA) in chlamydial pathogenesis is not clear. Results The cHtrA was detected both inside and outside the chlamydial inclusions. The detection was specific since both polyclonal and monoclonal anti-cHtrA antibodies revealed similar intracellular labeling patterns that were only removed by absorption with cHtrA but not control fusion proteins. In a Western blot assay, the anti-cHtrA antibodies detected the endogenous cHtrA in Chlamydia-infected cells without cross-reacting with any other chlamydial or host cell antigens. Fractionation of the infected cells revealed cHtrA in the host cell cytosol fraction. The periplasmic cHtrA protein appeared to be actively secreted into host cell cytosol since no other chlamydial periplasmic proteins were detected in the host cell cytoplasm. Most chlamydial species secreted cHtrA into host cell cytosol and the secretion was not inhibitable by a type III secretion inhibitor. Conclusion Since it is hypothesized that chlamydial organisms possess a proteolysis strategy to manipulate host cell signaling pathways, secretion of the serine protease cHtrA into host cell cytosol suggests that the periplasmic cHtrA may also play an important role in chlamydial interactions with host cells.
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Sharma J, Mishra BB, Li Q, Teale JM. TLR4-dependent activation of inflammatory cytokine response in macrophages by Francisella elongation factor Tu. Cell Immunol 2011; 269:69-73. [PMID: 21497800 PMCID: PMC3106127 DOI: 10.1016/j.cellimm.2011.03.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 03/06/2011] [Accepted: 03/24/2011] [Indexed: 01/21/2023]
Abstract
The bacterial determinants of pulmonary Francisella induced inflammatory responses and their interaction with host components are not clearly defined. In this study, proteomic and immunoblot analyses showed presence of a cytoplasmic protein elongation factor Tu (EF-Tu) in the membrane fractions of virulent Francisella novicida, LVS and SchuS4, but not in an attenuated F. novicida mutant. EF-Tu was immunodominant in mice vaccinated and protected from virulent F. novicida. Moreover, recombinant EF-Tu induced macrophages to produce inflammatory cytokines in a TLR4 dependent manner. This study shows immune stimulatory properties of a cytoplasmic protein EF-Tu expressed on the membrane of virulent Francisella strains.
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Affiliation(s)
- Jyotika Sharma
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, TX 78249-1644, United States.
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Chlamydia trachomatis secretion of an immunodominant hypothetical protein (CT795) into host cell cytoplasm. J Bacteriol 2011; 193:2498-509. [PMID: 21441519 DOI: 10.1128/jb.01301-10] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Chlamydia-specific hypothetical protein CT795 was dominantly recognized by human antisera produced during C. trachomatis infection but not by animal antisera raised against dead chlamydia organisms. The immundominant region recognized by the human antibodies was mapped to the N-terminal fragment T22-S69. The endogenous CT795 was detected in the cytoplasm of host cells during C. trachomatis infection and was highly enriched in the host cytosolic fraction but absent in the purified chlamydia organisms, suggesting that CT795 is synthesized and secreted into host cell cytoplasm without incorporation into the organisms. All C. trachomatis serovars tested secreted CT795. A predicted signal peptide of CT795 directed the mature PhoA to cross Escherichia coli inner membranes. The secretion of CT795 in Chlamydia-infected cells was inhibited by a C(16) compound targeting signal peptidase I, but not by a C(1) compound known to block the type III secretion pathway. These results suggest that CT795, like CPAF (a Chlamydia-secreted virulence factor), is secreted into the host cell cytoplasm via a sec-dependent mechanism and not by a type III secretion pathway. The above characterizations of CT795 have provided important information for further understanding the potential roles of CT795 in C. trachomatis pathogenesis.
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A Chlamydia trachomatis OmcB C-terminal fragment is released into the host cell cytoplasm and is immunogenic in humans. Infect Immun 2011; 79:2193-203. [PMID: 21422182 DOI: 10.1128/iai.00003-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Chlamydia trachomatis outer 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 in C. 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 the C. 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 of C. trachomatis. Moreover, the released OmcBc but not the retained OmcBn was highly immunogenic in C. 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.
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Dehoux P, Flores R, Dauga C, Zhong G, Subtil A. Multi-genome identification and characterization of chlamydiae-specific type III secretion substrates: the Inc proteins. BMC Genomics 2011; 12:109. [PMID: 21324157 PMCID: PMC3048545 DOI: 10.1186/1471-2164-12-109] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 02/16/2011] [Indexed: 12/13/2022] Open
Abstract
Background Chlamydiae are obligate intracellular bacteria that multiply in a vacuolar compartment, the inclusion. Several chlamydial proteins containing a bilobal hydrophobic domain are translocated by a type III secretion (TTS) mechanism into the inclusion membrane. They form the family of Inc proteins, which is specific to this phylum. Based on their localization, Inc proteins likely play important roles in the interactions between the microbe and the host. In this paper we sought to identify and analyze, using bioinformatics tools, all putative Inc proteins in published chlamydial genomes, including an environmental species. Results Inc proteins contain at least one bilobal hydrophobic domain made of two transmembrane helices separated by a loop of less than 30 amino acids. Using bioinformatics tools we identified 537 putative Inc proteins across seven chlamydial proteomes. The amino-terminal segment of the putative Inc proteins was recognized as a functional TTS signal in 90% of the C. trachomatis and C. pneumoniae sequences tested, validating the data obtained in silico. We identified a macro domain in several putative Inc proteins, and observed that Inc proteins are enriched in segments predicted to form coiled coils. A surprisingly large proportion of the putative Inc proteins are not constitutively translocated to the inclusion membrane in culture conditions. Conclusions The Inc proteins represent 7 to 10% of each proteome and show a great degree of sequence diversity between species. The abundance of segments with a high probability for coiled coil conformation in Inc proteins support the hypothesis that they interact with host proteins. While the large majority of Inc proteins possess a functional TTS signal, less than half may be constitutively translocated to the inclusion surface in some species. This suggests the novel finding that translocation of Inc proteins may be regulated by as-yet undetermined mechanisms.
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Affiliation(s)
- Pierre Dehoux
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, Paris, France
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Gong S, Lei L, Chang X, Belland R, Zhong G. Chlamydia trachomatis secretion of hypothetical protein CT622 into host cell cytoplasm via a secretion pathway that can be inhibited by the type III secretion system inhibitor compound 1. MICROBIOLOGY-SGM 2011; 157:1134-1144. [PMID: 21233161 DOI: 10.1099/mic.0.047746-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Using antibodies raised with C. trachomatis fusion proteins, we localized a hypothetical protein encoded by the ORF ct622 in the cytoplasm of C. trachomatis-infected mammalian cells. The detection was specific since the antibody labelling of CT622 protein was removed by preabsorption with CT622 but not other fusion proteins. We similarly confirmed that CT621, a known secretion protein encoded by a hypothetical ORF downstream of ct622, was secreted into host cell cytosol. Proteins CT622 and CT621 displayed a similar secretion pattern, with both intra-inclusion and host cell cytosol localization, that was distinct from that of CPAF (chlamydial protease/proteasome-like activity factor). However, the expression and secretion kinetics differed significantly between CT622 and CT621: CT622 mRNA was detected at 2 h, protein at 6 h and secretion of protein into host cell cytoplasm at 36 h post-infection, while CT621 mRNA was detected at 8 h, protein at 16 h and secretion at 24 h. The secretion of both CT622 and CT621 was blocked by N'-(3,5-dibromo-2-hydroxybenzylidene)-4-nitrobenzohydrazide (compound 1), an inhibitor known to target the type III secretion system of bacteria. These results suggest that CT621 and CT622 may fulfil different functions during chlamydial intracellular growth. Further characterization of these proteins may generate important information for understanding chlamydial pathogenesis.
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Affiliation(s)
- Siqi Gong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Lei Lei
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Xiaotong Chang
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Robert Belland
- Department of Molecular Sciences, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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Cochrane M, Armitage CW, O’Meara CP, Beagley KW. Towards a Chlamydia trachomatis vaccine: how close are we? Future Microbiol 2010; 5:1833-56. [DOI: 10.2217/fmb.10.148] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Chlamydia trachomatis is the leading cause of bacterial sexually transmitted infections and preventable blindness worldwide. The incidence of chlamydial sexually transmitted infections has increased rapidly and current antibiotic therapy has failed as an intervention strategy. The most accepted strategy for protection and/or control of chlamydial infections is a vaccine that induces both local neutralizing antibodies to prevent infections by the extracellular elementary bodies and a cell-mediated immune response to target the intracellular infection. This article will discuss the challenges in vaccine design for the prevention of chlamydial urogenital infection and/or disease, including selection of target antigens, discussion of effective delivery systems, immunization routes and adjuvants for induction of protective immunity at the targeted mucosal surface whilst minimizing severe inflammatory disease sequelae.
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Affiliation(s)
- Melanie Cochrane
- Institute of Health & Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia
| | - Charles W Armitage
- Institute of Health & Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia
| | - Connor P O’Meara
- Institute of Health & Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia
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Rodgers AK, Wang J, Zhang Y, Holden A, Berryhill B, Budrys NM, Schenken RS, Zhong G. Association of tubal factor infertility with elevated antibodies to Chlamydia trachomatis caseinolytic protease P. Am J Obstet Gynecol 2010; 203:494.e7-494.e14. [PMID: 20643392 DOI: 10.1016/j.ajog.2010.06.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Revised: 05/20/2010] [Accepted: 06/01/2010] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The objective of the study was to assess antibodies against Chlamydia trachomatis heat shock proteins (HSP) in patients with tubal factor infertility (TFI), infertility controls (IFC), and fertile controls (FC). HSPs assist organisms in surviving caustic environments such as heat. STUDY DESIGN Twenty-one TFI, 15 IFC, and 29 FC patients were enrolled after laparoscopic tubal assessment. The titers of antibodies against C trachomatis organisms and 14 chlamydial HSPs were compared among the 3 groups. RESULTS TFI patients developed significantly higher levels of antibodies against C trachomatis and specifically recognizing chlamydial HSP60 and caseinolytic protease (Clp) P, a subunit of the ATP-dependent Clp protease complex involved in the degradation of abnormal proteins. CONCLUSION In addition to confirming high titers of antibodies against C trachomatis organisms and HSP60 in TFI patients, we identified a novel link of TFI with anti-ClpP antibodies. These findings may provide useful information for developing a noninvasive screening test for TFI and constructing subunit anti-C trachomatis vaccines.
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Affiliation(s)
- Allison K Rodgers
- Department of Obstetrics and Gynecology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229,USA
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Identification of immunodominant antigens by probing a whole Chlamydia trachomatis open reading frame proteome microarray using sera from immunized mice. Infect Immun 2010; 79:246-57. [PMID: 20956570 DOI: 10.1128/iai.00626-10] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Chlamydia trachomatis infections can lead to severe chronic complications, including trachoma, ectopic pregnancy, and infertility. The only effective approach to disease control is vaccination. The goal of this work was to identify new potential vaccine candidates through a proteomics approach. We constructed a protein chip array (Antigen Discovery, Inc.) by expressing the open reading frames (ORFs) from C. trachomatis mouse pneumonitis (MoPn) genomic and plasmid DNA and tested it with serum samples from MoPn-immunized mice. Two groups of BALB/c female mice were immunized either intranasally or intravaginally with live elementary bodies (EB). Another two groups were immunized by a combination of the intramuscular and subcutaneous routes with UV-treated EB (UV-EB), using either CpG and Montanide as adjuvants to favor a Th1 response or alum to elicit a Th2 response. Serum samples collected at regular intervals postimmunization were tested in the proteome array. The microarray included the expression products of 909 proteins from a total of 921 ORFs of the Chlamydia MoPn genome and plasmid. A total of 185 immunodominant proteins elicited an early and sustained antibody response in the mice immunized with live EB, and of these, 71 were also recognized by the sera from mice immunized with UV-EB. The reactive antigens included some proteins that were previously described as immunogenic, such as the major outer membrane protein, OmpB, Hsp60, and IncA and proteins from the type III secretion system. In addition, we identified in mice several new immunogens, including 75 hypothetical proteins. In summary, we have identified a new group of immunodominant chlamydial proteins that can be tested for their ability to induce protection.
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Characterization of Pgp3, a Chlamydia trachomatis plasmid-encoded immunodominant antigen. J Bacteriol 2010; 192:6017-24. [PMID: 20851898 DOI: 10.1128/jb.00847-10] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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.
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Abstract
The Plasmodium parasite, the causative agent of malaria, is an excellent model for immunomic-based approaches to vaccine development. The Plasmodium parasite has a complex life cycle with multiple stages and stage-specific expression of ∼5300 putative proteins. No malaria vaccine has yet been licensed. Many believe that an effective vaccine will need to target several antigens and multiple stages, and will require the generation of both antibody and cellular immune responses. Vaccine efforts to date have been stage-specific and based on only a very limited number of proteins representing <0.5% of the genome. The recent availability of comprehensive genomic, proteomic and transcriptomic datasets from human and selected non-human primate and rodent malarias provide a foundation to exploit for vaccine development. This information can be mined to identify promising vaccine candidate antigens, by proteome-wide screening of antibody and T cell reactivity using specimens from individuals exposed to malaria and technology platforms such as protein arrays, high throughput protein production and epitope prediction algorithms. Such antigens could be incorporated into a rational vaccine development process that targets specific stages of the Plasmodium parasite life cycle with immune responses implicated in parasite elimination and control. Immunomic approaches which enable the selection of the best possible targets by prioritising antigens according to clinically relevant criteria may overcome the problem of poorly immunogenic, poorly protective vaccines that has plagued malaria vaccine developers for the past 25 years. Herein, current progress and perspectives regarding Plasmodium immunomics are reviewed.
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Affiliation(s)
- Denise L Doolan
- Division of Immunology, Queensland Institute of Medical Research, The Bancroft Centre, 300 Herston Road, P.O. Royal Brisbane Hospital, Brisbane, QLD 4029, Australia.
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Immunodominant regions of a Chlamydia trachomatis type III secretion effector protein, Tarp. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2010; 17:1371-6. [PMID: 20668138 DOI: 10.1128/cvi.00218-10] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have previously shown that individuals infected with Chlamydia trachomatis can develop a robust antibody response to a Chlamydia type III secretion effector protein called Tarp and that immunization with Tarp induces protection against challenge infection in mice. The current study aimed to map the immunodominant regions of the Tarp protein by expressing 11 fragments of Tarp as glutathione S-transferase (GST) fusion proteins and detecting the reactivity of these fusion proteins with antisera from patients infected with C. trachomatis in the urogenital tract or in the ocular tissue and from rabbits immunized with C. trachomatis organisms. A major immunodominant region was strongly recognized by all antibodies. This region covers amino acids 152 to 302, consisting of three repeats (amino acids 152 to 201, 202 to 251, and 252 to 302). Each of the repeats contains multiple tyrosine residues that are phosphorylated by host cell kinases when Tarp is injected into host cells. Several other minor immunodominant regions were also identified, including those comprising amino acids 1 to 156, 310 to 431, and 582 to 682 (recognized by antisera from both humans and rabbits), that comprising amino acids 425 to 581 (recognized only by human antisera), and that comprising amino acids 683 to 847 (preferentially recognized by rabbit antisera). This immunodominance was also confirmed by the observations that six out of the nine monoclonal antibodies (MAbs) bound to the major immunodominant region and that the other three each bound to one of the minor fragments, comprising amino acids 1 to 119, 120 to 151, and 310 to 431. The antigenicity analyses have provided important information for further understanding the structure and function of Tarp.
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Wang J, Zhang Y, Lu C, Lei L, Yu P, Zhong G. A genome-wide profiling of the humoral immune response to Chlamydia trachomatis infection reveals vaccine candidate antigens expressed in humans. THE JOURNAL OF IMMUNOLOGY 2010; 185:1670-80. [PMID: 20581152 DOI: 10.4049/jimmunol.1001240] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A whole genome scale proteome array consisting of 908 open reading frames encoded in Chlamydia trachomatis genome and plasmid was used to profile anti-chlamydial Ab responses. A total of 719 chlamydial proteins was recognized by one or more antisera from 99 women urogenitally infected with C. trachomatis. Revealing such a large C. trachomatis ANTIGENome in humans might partially be attributed to the significantly improved detection sensitivity of the whole genome scale proteome array assay because both linear and conformation-dependent Abs were detected by the array assay. Twenty-seven of the 719 Ags were recognized by >or=50% antisera, thus designated as immunodominant Ags. Comparison of Ag profiles recognized by live chlamydial organism-infected versus dead organism-immunized hosts led to the identification of infection-dependent or in vivo expressed Ags. The infection-dependent Ags induced Abs only in live organism-infected, but not in dead organism-immunized hosts. Many of these Ags were highly expressed during replication, but only minimally packaged into the infectious elementary bodies. Because inactivated whole chlamydial organism-based vaccines failed to induce protection in humans, identification of the infection-dependent or in vivo expressed immunodominant Ags in humans should greatly facilitate the selection of promising chlamydial subunit vaccine candidates for further evaluation. This approach may also be applicable to other pathogens.
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Affiliation(s)
- Jie Wang
- Department of Microbiology and Immunology, University of Texas Health Science Center, San Antonio, TX 78229, USA
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Chen D, Lei L, Flores R, Huang Z, Wu Z, Chai J, Zhong G. Autoprocessing and self-activation of the secreted protease CPAF in Chlamydia-infected cells. Microb Pathog 2010; 49:164-73. [PMID: 20510344 DOI: 10.1016/j.micpath.2010.05.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 05/14/2010] [Accepted: 05/18/2010] [Indexed: 10/19/2022]
Abstract
The Chlamydia-secreted protease/proteasome-like activity factor (CPAF) is synthesized as a proenzyme (proCPAF) and requires processing for proteolytic activity. Recent structural studies have further demonstrated that CPAF is a serine protease that can undergo autoprocessing and self-activation in a concentration-dependent manner in vitro. However, it is not known how CPAF is processed and activated during chlamydial infection. In the current study, we used a mutant CPAF designated as CPAF(E558A) that is deficient in processing by itself as a substrate to search for putative CPAF activation factor(s) in Chlamydia-infected cells. CPAF(E558A) was processed by the lysates made from Chlamydia-infected cells and the processing activity correlated with the presence of endogenous active CPAF in the fractionated lysate samples. CPAF produced in the Chlamydia-infected cells is required for processing the mutant CPAF(E558A) since the processing activity was removed by depletion with anti-CPAF but not control antibodies. Furthermore, a purified and activated wild type CPAF alone was sufficient for processing CPAF(E558A) and no other chlamydial proteases are required. Finally, fusion tag-induced oligomerization can lead to autoprocessing and self-activation of the wild type CPAF in mammalian cells. These observations together have demonstrated that CPAF undergoes autoprocessing and self-activation during chlamydial infection.
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Affiliation(s)
- Ding Chen
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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Skwor T, Kandel RP, Basravi S, Khan A, Sharma B, Dean D. Characterization of humoral immune responses to chlamydial HSP60, CPAF, and CT795 in inflammatory and severe trachoma. Invest Ophthalmol Vis Sci 2010; 51:5128-36. [PMID: 20463311 DOI: 10.1167/iovs.09-5113] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
PURPOSE Chlamydia trachomatis (Ct) remains the leading global cause of preventable blindness. There are limited data on humoral immune responses in trachoma. Evaluating these responses is important for understanding host-pathogen interactions and informing vaccine design. Antibodies to chlamydial heat shock protein 60 (cHSP60) have been associated with infertility and trachomatous scarring. Other proteins, including chlamydial protease-associated factor (CPAF) and a hypothetical protein unique to the family Chlamydiaceae, CT795, elicit strong immune responses in urogenital infections, but their role in trachomatous disease is unknown. METHODS This study was conducted to expand on previous cHSP60 findings and evaluate the association of CPAF and CT795 antibodies with ocular Ct infection and disease. Clinical trachoma grading was performed, and conjunctival samples were obtained from individuals with trachomatous trichiasis (TT; one or more inturned eyelashes) or inflammatory trachoma without trichiasis and control subjects without disease, all of whom resided in trachoma-endemic regions of Nepal. Ct infection was determined using commercial PCR. IgG and IgA tear antibodies against cHSP60, CT795, and CPAF fusion proteins were measured by quantitative ELISA. RESULTS Significantly higher IgG antibody levels were found against cHSP60, CPAF, and CT795 in the inflammatory cases compared with levels in the controls (P < 0.005 for all three). Ct infection was independently associated with IgG antibodies against all three immunogens in the inflammatory cases but not in the controls (P = 0.025, P = 0.03 and P = 0.017, respectively). Only IgG antibodies against CPAF were significantly elevated among the TT cases (P = 0.013). CONCLUSIONS Among individuals with trachoma, IgG antibody responses to CPAF are likely to be both a marker and risk factor for inflammatory trachoma and severe trachomatous disease.
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Affiliation(s)
- Troy Skwor
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, California 94609, USA
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