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DeBoer AG, Lei L, Yang C, Martens CA, Anzick SL, Antonioli-Schmit S, Suchland RJ, McClarty G, Caldwell HD, Rockey DD. TargeTron Inactivation of Chlamydia trachomatis gseA Results in a Lipopolysaccharide 3-Deoxy-d-Manno-Oct-2-Ulosonic Acid-Deficient Strain That Is Cytotoxic for Cells. Infect Immun 2023; 91:e0009623. [PMID: 37255490 PMCID: PMC10353364 DOI: 10.1128/iai.00096-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 03/17/2023] [Indexed: 06/01/2023] Open
Abstract
All members of the family Chlamydiaceae have lipopolysaccharides (LPS) that possess a shared carbohydrate trisaccharide antigen, 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) that is functionally uncharacterized. A single gene, genus-specific epitope (gseA), is responsible for attaching the tri-Kdo to lipid IVA. To investigate the function of Kdo in chlamydial host cell interactions, we made a gseA-null strain (L2ΔgseA) by using TargeTron mutagenesis. Immunofluorescence microscopy and immunoblotting with a Kdo-specific monoclonal antibody demonstrated that L2ΔgseA lacked Kdo. L2ΔgseA reacted by immunoblotting with a monoclonal antibody specific for a conserved LPS glucosamine-PO4 epitope, indicating that core lipid A was retained by the mutant. The mutant strain produced a similar number of inclusions as the parental strain but yielded lower numbers of infectious elementary bodies. Transmission electron microscopy of L2ΔgseA-infected cells showed atypical developmental forms and a reduction in the number of elementary bodies. Immunoblotting of dithiothreitol-treated L2ΔgseA-infected cells lysates revealed a marked reduction in outer membrane OmcB disulfide cross-linking, suggesting that the elementary body outer membrane structure was affected by the lack of Kdo. Notably, lactic acid dehydrogenase release by infected cells demonstrated that L2ΔgseA was significantly more cytotoxic to host cells than the wild type. The cytotoxic phenotype may result from an altered outer membrane biogenesis structure and/or function or, conversely, from a direct pathobiological effect of Kdo on an unknown host cell target. These findings implicate a previously unrecognized role for Kdo in host cell interactions that facilitates postinfection host cell survival.
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Affiliation(s)
- Addison G. DeBoer
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Lei Lei
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Chunfu Yang
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Craig A. Martens
- National Institute of Allergy and Infectious Disease, Rocky Mountain Laboratory, Hamilton, Montana, USA
| | - Sarah L. Anzick
- National Institute of Allergy and Infectious Disease, Rocky Mountain Laboratory, Hamilton, Montana, USA
| | - Sophia Antonioli-Schmit
- National Institute of Allergy and Infectious Disease, Rocky Mountain Laboratory, Hamilton, Montana, USA
| | - Robert J. Suchland
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington
| | - Grant McClarty
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba Winnipeg, Winnipeg, Manitoba, Canada
| | - Harlan D. Caldwell
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Daniel D. Rockey
- Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon, USA
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2
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Lipopolysaccharides and Cellular Senescence: Involvement in Atherosclerosis. Int J Mol Sci 2022; 23:ijms231911148. [PMID: 36232471 PMCID: PMC9569556 DOI: 10.3390/ijms231911148] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/17/2022] [Accepted: 09/19/2022] [Indexed: 11/17/2022] Open
Abstract
Atherosclerosis is a chronic inflammatory disease of the vascular walls related to aging. Thus far, the roles of cellular senescence and bacterial infection in the pathogenesis of atherosclerosis have been speculated to be independent of each other. Some types of macrophages, vascular endothelial cells, and vascular smooth muscle cells are in a senescent state at the sites of atherosclerotic lesions. Likewise, bacterial infections and accumulations of lipopolysaccharide (LPS), an outer-membrane component of Gram-negative bacteria, have also been observed in the atherosclerotic lesions of patients. This review introduces the integration of these two potential pathways in atherosclerosis. Previous studies have suggested that LPS directly induces cellular senescence in cultured monocytes/macrophages and vascular cells. In addition, LPS enhances the inflammatory properties (senescence-associated secretory phenotype [SASP]) of senescent endothelial cells. Thus, LPS derived from Gram-negative bacteria could exaggerate the pathogenesis of atherosclerosis by inducing and enhancing cellular senescence and the SASP-associated inflammatory properties of specific vascular cells in atherosclerotic lesions. This proposed mechanism can provide novel approaches to preventing and treating this common age-related disease.
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Szulc-Dąbrowska L, Bossowska-Nowicka M, Struzik J, Toka FN. Cathepsins in Bacteria-Macrophage Interaction: Defenders or Victims of Circumstance? Front Cell Infect Microbiol 2020; 10:601072. [PMID: 33344265 PMCID: PMC7746538 DOI: 10.3389/fcimb.2020.601072] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/05/2020] [Indexed: 02/06/2023] Open
Abstract
Macrophages are the first encounters of invading bacteria and are responsible for engulfing and digesting pathogens through phagocytosis leading to initiation of the innate inflammatory response. Intracellular digestion occurs through a close relationship between phagocytic/endocytic and lysosomal pathways, in which proteolytic enzymes, such as cathepsins, are involved. The presence of cathepsins in the endo-lysosomal compartment permits direct interaction with and killing of bacteria, and may contribute to processing of bacterial antigens for presentation, an event necessary for the induction of antibacterial adaptive immune response. Therefore, it is not surprising that bacteria can control the expression and proteolytic activity of cathepsins, including their inhibitors – cystatins, to favor their own intracellular survival in macrophages. In this review, we summarize recent developments in defining the role of cathepsins in bacteria-macrophage interaction and describe important strategies engaged by bacteria to manipulate cathepsin expression and activity in macrophages. Particularly, we focus on specific bacterial species due to their clinical relevance to humans and animal health, i.e., Mycobacterium, Mycoplasma, Staphylococcus, Streptococcus, Salmonella, Shigella, Francisella, Chlamydia, Listeria, Brucella, Helicobacter, Neisseria, and other genera.
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Affiliation(s)
- Lidia Szulc-Dąbrowska
- Division of Immunology, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences-Szkoła Główna Gospodarstwa Wejskiego, Warsaw, Poland
| | - Magdalena Bossowska-Nowicka
- Division of Immunology, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences-Szkoła Główna Gospodarstwa Wejskiego, Warsaw, Poland
| | - Justyna Struzik
- Division of Immunology, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences-Szkoła Główna Gospodarstwa Wejskiego, Warsaw, Poland
| | - Felix N Toka
- Division of Immunology, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences-Szkoła Główna Gospodarstwa Wejskiego, Warsaw, Poland.,Center for Integrative Mammalian Research, Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis
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4
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Single-gene lysis in the metagenomic era. Curr Opin Microbiol 2020; 56:109-117. [PMID: 33075663 DOI: 10.1016/j.mib.2020.09.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 08/20/2020] [Accepted: 09/30/2020] [Indexed: 12/17/2022]
Abstract
The small lytic phages (Microviridae and Leviviridae), effect bacterial lysis with the product of a single gene. The three well-studied single-gene lysis (Sgl) proteins (E of φX174, A2 of Qβ, and LysM of phage M) lack direct muralytic activity, and have been shown to function as 'protein antibiotics' by acting as noncompetitive inhibitors of conserved peptidoglycan (PG) biosynthesis enzymes, MurA, MraY, and MurJ respectively. The fourth, protein L of MS2, does not inhibit PG biosynthesis but instead is hypothesized to trigger host autolytic response through an unknown mechanism. Recent advances in meta-omics approaches have led to an explosion in the available genomes of small lytic phages. Of the thousands of new genomes, only one annotated Sgl shared some sequence similarity with a known Sgl (L of MS2), highlighting the diversity in Sgls. The newly available genomic space serves as an untapped resource for discovering novel Sgls.
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Horne JE, Brockwell DJ, Radford SE. Role of the lipid bilayer in outer membrane protein folding in Gram-negative bacteria. J Biol Chem 2020; 295:10340-10367. [PMID: 32499369 PMCID: PMC7383365 DOI: 10.1074/jbc.rev120.011473] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 06/03/2020] [Indexed: 01/09/2023] Open
Abstract
β-Barrel outer membrane proteins (OMPs) represent the major proteinaceous component of the outer membrane (OM) of Gram-negative bacteria. These proteins perform key roles in cell structure and morphology, nutrient acquisition, colonization and invasion, and protection against external toxic threats such as antibiotics. To become functional, OMPs must fold and insert into a crowded and asymmetric OM that lacks much freely accessible lipid. This feat is accomplished in the absence of an external energy source and is thought to be driven by the high thermodynamic stability of folded OMPs in the OM. With such a stable fold, the challenge that bacteria face in assembling OMPs into the OM is how to overcome the initial energy barrier of membrane insertion. In this review, we highlight the roles of the lipid environment and the OM in modulating the OMP-folding landscape and discuss the factors that guide folding in vitro and in vivo We particularly focus on the composition, architecture, and physical properties of the OM and how an understanding of the folding properties of OMPs in vitro can help explain the challenges they encounter during folding in vivo Current models of OMP biogenesis in the cellular environment are still in flux, but the stakes for improving the accuracy of these models are high. OMP folding is an essential process in all Gram-negative bacteria, and considering the looming crisis of widespread microbial drug resistance it is an attractive target. To bring down this vital OMP-supported barrier to antibiotics, we must first understand how bacterial cells build it.
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Affiliation(s)
- Jim E Horne
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - David J Brockwell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
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Abstract
The evolutionary separated Gram-negative Chlamydiales show a biphasic life cycle and replicate exclusively within eukaryotic host cells. Members of the genus Chlamydia are responsible for many acute and chronic diseases in humans, and Chlamydia-related bacteria are emerging pathogens. We revisit past efforts to detect cell wall material in Chlamydia and Chlamydia-related bacteria in the context of recent breakthroughs in elucidating the underlying cellular and molecular mechanisms of the chlamydial cell wall biosynthesis. In this review, we also discuss the role of cell wall biosynthesis in chlamydial FtsZ-independent cell division and immune modulation. In the past, penicillin susceptibility of an invisible wall was referred to as the "chlamydial anomaly." In light of new mechanistic insights, chlamydiae may now emerge as model systems to understand how a minimal and modified cell wall biosynthetic machine supports bacterial cell division and how cell wall-targeting beta-lactam antibiotics can also act bacteriostatically rather than bactericidal. On the heels of these discussions, we also delve into the effects of other cell wall antibiotics in individual chlamydial lineages.
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7
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Loeper N, Graspeuntner S, Ledig S, Kaufhold I, Hoellen F, Schiefer A, Henrichfreise B, Pfarr K, Hoerauf A, Shima K, Rupp J. Elaborations on Corallopyronin A as a Novel Treatment Strategy Against Genital Chlamydial Infections. Front Microbiol 2019; 10:943. [PMID: 31134007 PMCID: PMC6514060 DOI: 10.3389/fmicb.2019.00943] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 04/15/2019] [Indexed: 11/13/2022] Open
Abstract
Ascending Chlamydia trachomatis infection causes functional damage to the fallopian tubes, which may lead to ectopic pregnancy and infertility in women. Treatment failures using the standard regimens of doxycycline and azithromycin have been observed. We tested the polyketide-derived α-pyrone antibiotic Corallopyronin A (CorA) that inhibits the bacterial DNA dependent RNA polymerase and has strong activity against various extracellular and some intracellular bacteria. Extensive testing in cell culture infection models and in an ex vivo human fallopian tube model under different oxygen concentrations was performed to assess the anti-chlamydial efficacy of CorA at physiological conditions. CorA showed high efficacy against C. trachomatis (MICN/H: 0.5 μg/mL for serovar D and L2), C. muridarum (MICN/H: 0.5 μg/mL), and C. pneumoniae (MICN/H: 1 μg/mL) under normoxic (N) and hypoxic (H) conditions. Recoverable inclusion forming units were significantly lower already at 0.25 μg/mL for all tested chlamydiae. CorA at a concentration of 1 μg/mL was also effective against already established C. trachomatis and C. pneumoniae infections (up to 24 h.p.i.) in epithelial cells, while efficacy against C. muridarum was limited to earlier time points. A preliminary study using a C. muridarum genital infection model revealed corresponding limitations in the efficacy. Importantly, in an ex vivo human fallopian tube model, the growth of C. trachomatis was significantly inhibited by CorA at concentrations of 1–2 μg/mL under normoxic and hypoxic conditions. The overall high efficacies of CorA against C. trachomatis in cell culture and an ex vivo human fallopian tube model under physiological oxygen concentrations qualifies this drug as a candidate that should be further investigated.
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Affiliation(s)
- Nathalie Loeper
- Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany
| | - Simon Graspeuntner
- Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany
| | - Svea Ledig
- Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany
| | - Inga Kaufhold
- Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany
| | - Friederike Hoellen
- Department of Obstetrics and Gynecology, University Hospital of Schleswig-Holstein, University of Lübeck, Lübeck, Germany
| | - Andrea Schiefer
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany.,German Center for Infection Research (DZIF), Partner Sites Bonn-Cologne/Hamburg-Lübeck-Borstel-Riems, Lübeck, Germany
| | - Beate Henrichfreise
- Institute of Pharmaceutical Microbiology, University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Kenneth Pfarr
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany.,German Center for Infection Research (DZIF), Partner Sites Bonn-Cologne/Hamburg-Lübeck-Borstel-Riems, Lübeck, Germany
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany.,German Center for Infection Research (DZIF), Partner Sites Bonn-Cologne/Hamburg-Lübeck-Borstel-Riems, Lübeck, Germany
| | - Kensuke Shima
- Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany
| | - Jan Rupp
- Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany.,German Center for Infection Research (DZIF), Partner Sites Bonn-Cologne/Hamburg-Lübeck-Borstel-Riems, Lübeck, Germany
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8
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Chlamydia trachomatis Lipopolysaccharide Evades the Canonical and Noncanonical Inflammatory Pathways To Subvert Innate Immunity. mBio 2019; 10:mBio.00595-19. [PMID: 31015326 PMCID: PMC6479002 DOI: 10.1128/mbio.00595-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Chlamydia trachomatis is the most common bacterial cause of sexually transmitted infections (STI). C. trachomatis STI are commonly asymptomatic, implying a pathogenic strategy for the evasion of innate inflammatory immune responses, a paradox as the C. trachomatis outer membrane contains lipopolysaccharide (LPS), a known potent agonist of inflammatory innate immunity. Here, we found that C. trachomatis LPS is not capable of engaging the canonical TLR4/MD-2 or noncanonical caspase-11 inflammatory pathways. The inability of C. trachomatis LPS to trigger innate immunity inflammatory pathways is related to its unique fatty acid structure. Evolutionary modification of the LPS structure likely evolved as a pathogenic strategy to silence innate host defense mechanisms. The findings might explain the high incidence of asymptomatic chlamydial genital infection. Chlamydia trachomatis is the most common bacterial cause of sexually transmitted infections. C. trachomatis sexually transmitted infections are commonly asymptomatic, implying a pathogenic strategy for the evasion of innate inflammatory immune responses, a paradox as the C. trachomatis outer membrane contains lipopolysaccharide (LPS), a known potent agonist of inflammatory innate immunity. Here, we studied the ability of chlamydial LPS to activate the proinflammatory canonical and noncanonical inflammasome pathways in mouse bone marrow-derived macrophages (BMDM). We show, in comparison to Escherichia coli LPS, that C. trachomatis LPS-treated BMDM produce significantly less IL-6, TNF, and type I interferon mRNA, indicating that downstream signaling through the canonical TLR4 myddosome and triffosome pathways was blocked. We confirmed this in C. trachomatis LPS-treated BMDM by showing the lack of NF-κB and IRF3 phosphorylation, respectively. Interestingly, C. trachomatis LPS bound CD14 and promoted its endocytosis; however; it did not promote efficient TLR4/MD-2 dimerization or endocytosis, known requirements for myddosome and triffosome signaling pathways. We further found that transfection of BMDM with C. trachomatis LPS did not cause pyroptotic cell ballooning, cytotoxicity, or IL-1β secretion, all characteristic features of noncanonical inflammasome activation. Western blotting confirmed that cytosolic C. trachomatis LPS failed to signal through caspase-11, as shown by the lack of gasdermin D, caspase-1, or IL-1β proteolytic cleavage. We propose that chlamydiae evolved a unique LPS structure as a pathogenic strategy to avoid canonical and noncanonical innate immune signaling and conclude that this strategy might explain the high incidence of asymptomatic infections.
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Lee J, Patel DS, Ståhle J, Park SJ, Kern NR, Kim S, Lee J, Cheng X, Valvano MA, Holst O, Knirel YA, Qi Y, Jo S, Klauda JB, Widmalm G, Im W. CHARMM-GUI Membrane Builder for Complex Biological Membrane Simulations with Glycolipids and Lipoglycans. J Chem Theory Comput 2018; 15:775-786. [PMID: 30525595 DOI: 10.1021/acs.jctc.8b01066] [Citation(s) in RCA: 322] [Impact Index Per Article: 53.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Glycolipids (such as glycoglycerolipids, glycosphingolipids, and glycosylphosphatidylinositol) and lipoglycans (such as lipopolysaccharides (LPS), lipooligosaccharides (LOS), mycobacterial lipoarabinomannan, and mycoplasma lipoglycans) are typically found on the surface of cell membranes and play crucial roles in various cellular functions. Characterizing their structure and dynamics at the molecular level is essential to understand their biological roles, but systematic generation of glycolipid and lipoglycan structures is challenging because of great variations in lipid structures and glycan sequences (i.e., carbohydrate types and their linkages). To facilitate the generation of all-atom glycolipid/LPS/LOS structures, we have developed Glycolipid Modeler and LPS Modeler in CHARMM-GUI ( http://www.charmm-gui.org ), a web-based interface that simplifies building of complex biological simulation systems. In addition, we have incorporated these modules into Membrane Builder so that users can readily build a complex symmetric or asymmetric biological membrane system with various glycolipids and LPS/LOS. These tools are expected to be useful in innovative and novel glycolipid/LPS/LOS modeling and simulation research by easing tedious and intricate steps in modeling complex biological systems and shall provide insight into structures, dynamics, and underlying mechanisms of complex glycolipid-/LPS-/LOS-containing biological membrane systems.
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Affiliation(s)
- Jumin Lee
- Departments of Biological Sciences and Bioengineering , Lehigh University , Bethlehem , Pennsylvania 18015 , United States
| | - Dhilon S Patel
- Departments of Biological Sciences and Bioengineering , Lehigh University , Bethlehem , Pennsylvania 18015 , United States
| | - Jonas Ståhle
- Department of Organic Chemistry, Arrhenius Laboratory , Stockholm University , SE-106 91 Stockholm , Sweden
| | - Sang-Jun Park
- Departments of Biological Sciences and Bioengineering , Lehigh University , Bethlehem , Pennsylvania 18015 , United States
| | - Nathan R Kern
- Departments of Biological Sciences and Bioengineering , Lehigh University , Bethlehem , Pennsylvania 18015 , United States
| | - Seonghoon Kim
- Departments of Biological Sciences and Bioengineering , Lehigh University , Bethlehem , Pennsylvania 18015 , United States
| | - Joonseong Lee
- Departments of Biological Sciences and Bioengineering , Lehigh University , Bethlehem , Pennsylvania 18015 , United States
| | - Xi Cheng
- State Key Laboratory of Drug Research , Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zuchongzhi Road , Shanghai 201203 , China
| | - Miguel A Valvano
- Wellcome-Wolfson Institute for Experimental Medicine , Queen's University Belfast BT9 7BL , United Kingdom
| | - Otto Holst
- Division of Structural Biochemistry, Research Center Borstel , Airway Research Center North, Member of the German Center for Lung Research (DZL) , D-23845 Borstel , Germany
| | - Yuriy A Knirel
- N. D. Zelinsky Institute of Organic Chemistry , Russian Academy of Sciences , 119991 Moscow , Russia
| | - Yifei Qi
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering , East China Normal University , Shanghai 200062 , China
| | - Sunhwan Jo
- Leadership Computing Facility , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Jeffery B Klauda
- Department of Chemical and Biomolecular Engineering and the Biophysics Graduate Program , University of Maryland , College Park , Maryland 20742 , United States
| | - Göran Widmalm
- Department of Organic Chemistry, Arrhenius Laboratory , Stockholm University , SE-106 91 Stockholm , Sweden
| | - Wonpil Im
- Departments of Biological Sciences and Bioengineering , Lehigh University , Bethlehem , Pennsylvania 18015 , United States
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Scherler A, Jacquier N, Greub G. Chlamydiales, Anaplasma and Bartonella: persistence and immune escape of intracellular bacteria. Microbes Infect 2017; 20:416-423. [PMID: 29162422 DOI: 10.1016/j.micinf.2017.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/06/2017] [Accepted: 11/07/2017] [Indexed: 12/25/2022]
Abstract
Intracellular bacteria, such as Chlamydiales, Anaplasma or Bartonella, need to persist inside their host in order to complete their developmental cycle and to infect new hosts. In order to escape from the host immune system, intracellular bacteria have developed diverse mechanisms of persistence, which can directly impact the health of their host.
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Affiliation(s)
- Aurélie Scherler
- Centre for Research on Intracellular Bacteria, Institute of Microbiology, University Hospital Centre and University of Lausanne, Lausanne, Switzerland
| | - Nicolas Jacquier
- Centre for Research on Intracellular Bacteria, Institute of Microbiology, University Hospital Centre and University of Lausanne, Lausanne, Switzerland
| | - Gilbert Greub
- Centre for Research on Intracellular Bacteria, Institute of Microbiology, University Hospital Centre and University of Lausanne, Lausanne, Switzerland.
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11
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Cram ED, Rockey DD, Dolan BP. Chlamydia spp. development is differentially altered by treatment with the LpxC inhibitor LPC-011. BMC Microbiol 2017; 17:98. [PMID: 28438125 PMCID: PMC5402638 DOI: 10.1186/s12866-017-0992-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 03/28/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chlamydia species are obligate intracellular bacteria that infect a broad range of mammalian hosts. Members of related genera are pathogens of a variety of vertebrate and invertebrate species. Despite the diversity of Chlamydia, all species contain an outer membrane lipooligosaccharide (LOS) that is comprised of a genus-conserved, and genus-defining, trisaccharide 3-deoxy-D-manno-oct-2-ulosonic acid Kdo region. Recent studies with lipopolysaccharide inhibitors demonstrate that LOS is important for the C. trachomatis developmental cycle during RB- > EB differentiation. Here, we explore the effects of one of these inhibitors, LPC-011, on the developmental cycle of five chlamydial species. RESULTS Sensitivity to the drug varied in some of the species and was conserved between others. We observed that inhibition of LOS biosynthesis in some chlamydial species induced formation of aberrant reticulate bodies, while in other species, no change was observed to the reticulate body. However, loss of LOS production prevented completion of the chlamydial reproductive cycle in all species tested. In previous studies we found that C. trachomatis and C. caviae infection enhances MHC class I antigen presentation of a model self-peptide. We find that treatment with LPC-011 prevents enhanced host-peptide presentation induced by infection with all chlamydial-species tested. CONCLUSIONS The data demonstrate that LOS synthesis is necessary for production of infectious progeny and inhibition of LOS synthesis induces aberrancy in certain chlamydial species, which has important implications for the use of LOS synthesis inhibitors as potential antibiotics.
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Affiliation(s)
- Erik D Cram
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, Corvallis, OR, 97331, USA.
| | - Daniel D Rockey
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, Corvallis, OR, 97331, USA
| | - Brian P Dolan
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, Corvallis, OR, 97331, USA
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12
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Cicero JM, Fisher TW, Qureshi JA, Stansly PA, Brown JK. Colonization and Intrusive Invasion of Potato Psyllid by 'Candidatus Liberibacter solanacearum'. PHYTOPATHOLOGY 2017; 107:36-49. [PMID: 27482628 DOI: 10.1094/phyto-03-16-0149-r] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Previous studies have shown that the fastidious bacterial plant pathogen 'Candidatus Liberibacter solanacearum' (CLso) is transmitted circulatively and propagatively by the potato psyllid (PoP) Bactericera cockerelli. In this study, the temporal and spatial interrelationships between CLso PoP were investigated by scanning electron microscopy of the digestive system of PoP immature and adult instars and salivary glands of adults post CLso ingestion. CLso biofilms were not detectable on the outer midgut surface of the first and second instars; however, for third to fifth instars and teneral and mature adults, biofilms were observed in increasing numbers in each successive developmental stage. In adult PoP midguts, CLso cells were observed between the basal lamina and basal epithelial cell membranes; in basal laminar perforations, on the outer basal laminar surface, and in the ventricular lumen, epithelial cytosol, and filter chamber periventricular space. CLso were also abundantly visible in the salivary gland pericellular spaces and in the epidermal cell cytosol of the head. Collectively, these results point to an intrusive, systemic invasion of PoP by CLso that employs an endo/exocytosis-like mechanism, in the context of a propagative, circulative mode of transmission.
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Affiliation(s)
- Joseph M Cicero
- First, second, and fifth authors: School of Plant Sciences, 303 Forbes Bld., University of Arizona, Tucson 85721; and third and fourth authors: Southwest Florida Research & Education Center, University of Florida IFAS, 2685 State Road 29 North, Immokalee 34142
| | - Tonja W Fisher
- First, second, and fifth authors: School of Plant Sciences, 303 Forbes Bld., University of Arizona, Tucson 85721; and third and fourth authors: Southwest Florida Research & Education Center, University of Florida IFAS, 2685 State Road 29 North, Immokalee 34142
| | - Jawwad A Qureshi
- First, second, and fifth authors: School of Plant Sciences, 303 Forbes Bld., University of Arizona, Tucson 85721; and third and fourth authors: Southwest Florida Research & Education Center, University of Florida IFAS, 2685 State Road 29 North, Immokalee 34142
| | - Philip A Stansly
- First, second, and fifth authors: School of Plant Sciences, 303 Forbes Bld., University of Arizona, Tucson 85721; and third and fourth authors: Southwest Florida Research & Education Center, University of Florida IFAS, 2685 State Road 29 North, Immokalee 34142
| | - Judith K Brown
- First, second, and fifth authors: School of Plant Sciences, 303 Forbes Bld., University of Arizona, Tucson 85721; and third and fourth authors: Southwest Florida Research & Education Center, University of Florida IFAS, 2685 State Road 29 North, Immokalee 34142
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13
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Structure of a bacterial type III secretion system in contact with a host membrane in situ. Nat Commun 2015; 6:10114. [PMID: 26656452 PMCID: PMC4682100 DOI: 10.1038/ncomms10114] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 11/03/2015] [Indexed: 12/16/2022] Open
Abstract
Many bacterial pathogens of animals and plants use a conserved type III secretion system (T3SS) to inject virulence effector proteins directly into eukaryotic cells to subvert host functions. Contact with host membranes is critical for T3SS activation, yet little is known about T3SS architecture in this state or the conformational changes that drive effector translocation. Here we use cryo-electron tomography and sub-tomogram averaging to derive the intact structure of the primordial Chlamydia trachomatis T3SS in the presence and absence of host membrane contact. Comparison of the averaged structures demonstrates a marked compaction of the basal body (4 nm) occurs when the needle tip contacts the host cell membrane. This compaction is coupled to a stabilization of the cytosolic sorting platform–ATPase. Our findings reveal the first structure of a bacterial T3SS from a major human pathogen engaged with a eukaryotic host, and reveal striking ‘pump-action' conformational changes that underpin effector injection. Bacterial type III secretion systems (T3SSs) inject virulence effector proteins into eukaryotic cells and are activated by host membrane contact. Here the authors report the in situ structure of the Chlamydia trachomatis T3SS in the presence or absence of host membrane, and observe compaction of the basal body embedded in the bacterial envelope.
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14
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The molecular mechanism of species-specific recognition of lipopolysaccharides by the MD-2/TLR4 receptor complex. Mol Immunol 2014; 63:134-42. [PMID: 25037631 DOI: 10.1016/j.molimm.2014.06.034] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/20/2014] [Accepted: 06/25/2014] [Indexed: 01/17/2023]
Abstract
Lipid A, a component of bacterial lipopolysaccharide, is a conserved microbe-associated molecular pattern that activates the MD-2/TLR4 receptor complex. Nevertheless, bacteria produce lipid A molecules of considerable structural diversity. The human MD-2/TLR4 receptor most efficiently recognizes hexaacylated bisphosphorylated lipid A produced by enterobacteria, but in some animal species the immune response can be elicited also by alternative lipid A varieties, such as tetraacylated lipid IVa or pentaacylated lipid A of Rhodobacter spheroides. Several crystal structures revealed that hexaacylated lipid A and tetraacylated lipid IVa activate the murine MD-2/TLR4 in a similar manner, but failed to explain the antagonistic vs. agonistic activity of lipid IVa in the human vs. equine receptor, respectively. Targeted mutagenesis studies of the receptor complex revealed intricate combination of electrostatic and hydrophobic interactions primarily within the MD-2 co-receptor, but with a contribution of TLR4 as well, that contribute to species-specific recognition of lipid A. We will review current knowledge regarding lipid A diversity and species-specific activation of the MD-2/TLR4 receptor complex in different species (e.g. human, mouse or equine) by lipid A varieties.
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15
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Yao J, Abdelrahman YM, Robertson RM, Cox JV, Belland RJ, White SW, Rock CO. Type II fatty acid synthesis is essential for the replication of Chlamydia trachomatis. J Biol Chem 2014; 289:22365-76. [PMID: 24958721 DOI: 10.1074/jbc.m114.584185] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The major phospholipid classes of the obligate intracellular bacterial parasite Chlamydia trachomatis are the same as its eukaryotic host except that they also contain chlamydia-made branched-chain fatty acids in the 2-position. Genomic analysis predicts that C. trachomatis is capable of type II fatty acid synthesis (FASII). AFN-1252 was deployed as a chemical tool to specifically inhibit the enoyl-acyl carrier protein reductase (FabI) of C. trachomatis to determine whether chlamydial FASII is essential for replication within the host. The C. trachomatis FabI (CtFabI) is a homotetramer and exhibited typical FabI kinetics, and its expression complemented an Escherichia coli fabI(Ts) strain. AFN-1252 inhibited CtFabI by binding to the FabI·NADH complex with an IC50 of 0.9 μM at saturating substrate concentration. The x-ray crystal structure of the CtFabI·NADH·AFN-1252 ternary complex revealed the specific interactions between the drug, protein, and cofactor within the substrate binding site. AFN-1252 treatment of C. trachomatis-infected HeLa cells at any point in the infectious cycle caused a decrease in infectious titers that correlated with a decrease in branched-chain fatty acid biosynthesis. AFN-1252 treatment at the time of infection prevented the first cell division of C. trachomatis, although the cell morphology suggested differentiation into a metabolically active reticulate body. These results demonstrate that FASII activity is essential for C. trachomatis proliferation within its eukaryotic host and validate CtFabI as a therapeutic target against C. trachomatis.
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Affiliation(s)
| | - Yasser M Abdelrahman
- the Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee 38163, and the Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo 11562, Egypt
| | - Rosanna M Robertson
- Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 48105
| | - John V Cox
- the Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee 38163, and
| | - Robert J Belland
- the Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee 38163, and
| | - Stephen W White
- Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 48105
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16
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Haji-Ghassemi O, Müller-Loennies S, Saldova R, Muniyappa M, Brade L, Rudd PM, Harvey DJ, Kosma P, Brade H, Evans SV. Groove-type recognition of chlamydiaceae-specific lipopolysaccharide antigen by a family of antibodies possessing an unusual variable heavy chain N-linked glycan. J Biol Chem 2014; 289:16644-61. [PMID: 24682362 DOI: 10.1074/jbc.m113.528224] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The structure of the antigen binding fragment of mAb S25-26, determined to 1.95 Å resolution in complex with the Chlamydiaceae family-specific trisaccharide antigen Kdo(2→8)Kdo(2→4)Kdo (Kdo = 3-deoxy-α-d-manno-oct-2-ulopyranosonic acid), displays a germ-line-coded paratope that differs significantly from previously characterized Chlamydiaceae-specific mAbs despite being raised against the identical immunogen. Unlike the terminal Kdo recognition pocket that promotes cross-reactivity in S25-2-type antibodies, S25-26 and the closely related S25-23 utilize a groove composed of germ-line residues to recognize the entire trisaccharide antigen and so confer strict specificity. Interest in S25-23 was sparked by its rare high μm affinity and strict specificity for the family-specific trisaccharide antigen; however, only the related antibody S25-26 proved amenable to crystallization. The structures of three unliganded forms of S25-26 have a labile complementary-determining region H3 adjacent to significant glycosylation of the variable heavy chain on asparagine 85 in Framework Region 3. Analysis of the glycan reveals a heterogeneous mixture with a common root structure that contains an unusually high number of terminal αGal-Gal moieties. One of the few reported structures of glycosylated mAbs containing these epitopes is the therapeutic antibody Cetuximab; however, unlike Cetuximab, one of the unliganded structures in S25-26 shows significant order in the glycan with appropriate electron density for nine residues. The elucidation of the three-dimensional structure of an αGal-containing N-linked glycan on a mAb variable heavy chain has potential clinical interest, as it has been implicated in allergic response in patients receiving therapeutic antibodies.
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Affiliation(s)
- Omid Haji-Ghassemi
- From the Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8P 3P6, Canada
| | - Sven Müller-Loennies
- Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 22, Borstel D-23845, Germany,
| | - Radka Saldova
- GlycoScience Group, the National Institute for Bioprocessing Research and Training (NIBRT), Mount Merrion, Blackrock, Dublin 4, Ireland
| | - Mohankumar Muniyappa
- GlycoScience Group, the National Institute for Bioprocessing Research and Training (NIBRT), Mount Merrion, Blackrock, Dublin 4, Ireland
| | - Lore Brade
- Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 22, Borstel D-23845, Germany
| | - Pauline M Rudd
- GlycoScience Group, the National Institute for Bioprocessing Research and Training (NIBRT), Mount Merrion, Blackrock, Dublin 4, Ireland
| | - David J Harvey
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Paul Kosma
- University of Natural Resources and Life Sciences, Vienna, Austria, and
| | - Helmut Brade
- Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 22, Borstel D-23845, Germany
| | - Stephen V Evans
- From the Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8P 3P6, Canada,
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17
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Lodowska J, Wolny D, Węglarz L. The sugar 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) as a characteristic component of bacterial endotoxin — a review of its biosynthesis, function, and placement in the lipopolysaccharide core. Can J Microbiol 2013; 59:645-55. [DOI: 10.1139/cjm-2013-0490] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The sugar 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) is a characteristic component of bacterial lipopolysaccharide (LPS, endotoxin). It connects the carbohydrate part of LPS with C6 of glucosamine or 2,3-diaminoglucose of lipid A by acid-labile α-ketosidic linkage. The number of Kdo units present in LPS, the way they are connected, and the occurrence of other substituents (P, PEtn, PPEtn, Gal, or β-l-Ara4N) account for structural diversity of the inner core region of endotoxin. In a majority of cases, Kdo is crucial to the viability and growth of bacterial cells. In this paper, the biosynthesis of Kdo and the mechanism of its incorporation into the LPS structure, as well as the location of this unique component in the endotoxin core structures, have been described.
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Affiliation(s)
- Jolanta Lodowska
- Department of Biochemistry, Faculty of Pharmacy, Medical University of Silesia, Narcyzow 1 Street, 41-200 Sosnowiec, Poland
| | - Daniel Wolny
- Department of Biopharmacy, Faculty of Pharmacy, Medical University of Silesia, Narcyzow 1 St., 41-200 Sosnowiec, Poland
| | - Ludmiła Węglarz
- Department of Biochemistry, Faculty of Pharmacy, Medical University of Silesia, Narcyzow 1 Street, 41-200 Sosnowiec, Poland
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18
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Duquenne P, Marchand G, Duchaine C. Measurement of endotoxins in bioaerosols at workplace: a critical review of literature and a standardization issue. ACTA ACUST UNITED AC 2012; 57:137-72. [PMID: 23002277 DOI: 10.1093/annhyg/mes051] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Endotoxins are lipopolysaccharides found in the outer membrane of most Gram-negative bacteria and cyanobacteria. Worker exposure to endotoxins has been shown in a number of work situations and is associated with both respiratory and systemic pathologies. The lack of an occupational exposure limit is mainly due to the absence of a standard protocol at the international level for sampling and analyzing airborne endotoxins. The bibliographic review in this article takes an exhaustive look at the current knowledge on measuring airborne endotoxins. It shows that, despite several reference documents at the international level, the methods used to measure endotoxin exposure differ considerably from one laboratory to another. Standardization is necessary to reduce interlaboratory variability and, ultimately, to improve the use of interstudy data. The bibliographic review presents the current status of standardization for airborne endotoxin measurement methods in the workplace and summarizes areas for further research. This article is both a reference document for all operators wishing to use such methods and a working document to build international consensus around the measurement of airborne endotoxins.
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Affiliation(s)
- Philippe Duquenne
- Laboratoire de Métrologie des Aérosols, Institut National de Recherche et de Sécurité, Vandoeuvre-Les-Nancy, France.
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19
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Petyaev IM, Zigangirova NA, Tsibezov VV, Ross A, Bashmakov YK. Monoclonal antibodies against lipopolysaccharide of Chlamydia trachomatis with cross reactivity to human ApoB. Hybridoma (Larchmt) 2011; 30:131-6. [PMID: 21529285 DOI: 10.1089/hyb.2010.0107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Splenocytes obtained from mice immunized with whole purified elementary bodies of Chlamydia trachomatis were used for hybridoma construction. The resulting clones were screened with ELISA using chlamydial lipopolysaccharide (LPS) and full-length human apolipoprotein B (ApoB). One analyzed clone producing IgG1 (MAb 7B5) showed simultaneous recognition of chlamydial LPS and human ApoB, suggesting the presence of common antigenic epitopes in their structures. MAb 7B5 exhibited agreeable activity in immunoblot analysis conducted using chlamydial extracts or full-length human ApoB as well as in immunofluorescence (IF) detecting typical inclusion bodies of C. trachomatis and C. pneumoniae in the infected eukaryotic host cells. The removal of LPS from chlamydial suspensions with lauroyl sarcosyl led to a complete disappearance of IF associated with the elementary bodies of C. trachomatis. Therefore, immunologic response to chlamydial antigen may be associated with the generation of ApoB-specific antibody. Molecular mimicry and subsequent formation of cross-reactive antibodies might be an essential mechanism explaining the appearance of circulating auto-antibodies against low density lipoproteins (LDL) in patients with atherosclerosis. Moreover, newly generated MAb 7B5 can be a useful tool in the laboratory diagnosis of chlamydial infections.
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Affiliation(s)
- Ivan M Petyaev
- Cambridge Theranostics Ltd., Babraham Research Campus, Babraham, Cambridge, United Kingdom
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20
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Sutcliffe IC. A phylum level perspective on bacterial cell envelope architecture. Trends Microbiol 2010; 18:464-70. [DOI: 10.1016/j.tim.2010.06.005] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Revised: 05/04/2010] [Accepted: 06/18/2010] [Indexed: 01/03/2023]
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21
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Fadel S, Eley A. Is lipopolysaccharide a factor in infectivity of Chlamydia trachomatis? J Med Microbiol 2008; 57:261-266. [PMID: 18287286 DOI: 10.1099/jmm.0.47237-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lipopolysaccharide (LPS) is a major surface component of Chlamydia trachomatis, as with all Gram-negative bacteria. The effect of C. trachomatis LPS on C. trachomatis infectivity of human epithelial cells was investigated. C. trachomatis LPS and C. trachomatis LPS antibody significantly reduced infectivity, mostly in a dose-dependent manner. As the structure of LPS in C. trachomatis is simple and consists only of lipid A and 3-deoxy-D-manno-octulosonic acid (Kdo), we investigated whether lipid A or Kdo was inhibitory to chlamydial infectivity. Polymyxin B, as a lipid A inhibitor, and Kdo considerably reduced C. trachomatis infectivity. With all the LPS inhibitors used, there was greater inhibition against serovar E than serovar LGV. These results suggest a role for LPS in chlamydial infectivity. Elucidation of how LPS acts in infectivity and identification of host-cell receptors would help in understanding pathogenicity.
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Affiliation(s)
- Sanaa Fadel
- Henry Wellcome Laboratories for Medical Research, Unit of Infection and Immunity, School of Medicine and Biomedical Sciences, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK
| | - Adrian Eley
- Henry Wellcome Laboratories for Medical Research, Unit of Infection and Immunity, School of Medicine and Biomedical Sciences, University of Sheffield Medical School, Beech Hill Road, Sheffield S10 2RX, UK
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22
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Bas S, Neff L, Vuillet M, Spenato U, Seya T, Matsumoto M, Gabay C. The proinflammatory cytokine response to Chlamydia trachomatis elementary bodies in human macrophages is partly mediated by a lipoprotein, the macrophage infectivity potentiator, through TLR2/TLR1/TLR6 and CD14. THE JOURNAL OF IMMUNOLOGY 2008; 180:1158-68. [PMID: 18178856 DOI: 10.4049/jimmunol.180.2.1158] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Chlamydiae components and signaling pathway(s) responsible for the production of proinflammatory cytokines by human monocytes/macrophages are not clearly identified. To this aim, Chlamydia trachomatis-inactivated elementary bodies (EB) as well as the following seven individual Ags were tested for their ability to induce the production of proinflammatory cytokines by human monocytes/macrophages and THP-1 cells: purified LPS, recombinant heat shock protein (rhsp)70, rhsp60, rhsp10, recombinant polypeptide encoded by open reading frame 3 of the plasmid (rpgp3), recombinant macrophage infectivity potentiator (rMip), and recombinant outer membrane protein 2 (rOmp2). Aside from EB, rMip displayed the highest ability to induce release of IL-1beta, TNF-alpha, IL-6, and IL-8. rMip proinflammatory activity could not be attributed to Escherichia coli LPS contamination as determined by the Limulus Amoebocyte lysate assay, insensitivity to polymyxin B (50 microg/ml), and different serum requirement. We have recently demonstrated that Mip is a "classical" bacterial lipoprotein, exposed at the surface of EB. The proinflammatory activity of EB was significantly attenuated in the presence of polyclonal Ab to rMip. Native Mip was able to induce TNF-alpha and IL-8 secretion, whereas a nonlipidated C20A rMip variant was not. Proinflammatory activity of rMip was unaffected by heat or proteinase K treatments but was greatly reduced by treatment with lipases, supporting a role of lipid modification in this process. Stimulating pathways appeared to involve TLR2/TLR1/TLR6 with the help of CD14 but not TLR4. These data support a role of Mip lipoprotein in pathogenesis of C. trachomatis-induced inflammatory responses.
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Affiliation(s)
- Sylvette Bas
- Division of Rheumatology, Department of Internal Medicine, University Hospital, and Department of Pathology and Immunology, Geneva Medical School, Switzerland.
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23
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Tsutsumi-Ishii Y, Shimada K, Daida H, Toman R, Nagaoka I. Low potency of Chlamydophila LPS to activate human mononuclear cells due to its reduced affinities for CD14 and LPS-binding protein. Int Immunol 2007; 20:199-208. [DOI: 10.1093/intimm/dxm129] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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24
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Kitazawa T, Fukushima A, Okugawa S, Yanagimoto S, Tsukada K, Tatsuno K, Koike K, Kimura S, Kishimoto T, Shibasaki Y, Ota Y. Chlamydophilal antigens induce foam cell formation via c-Jun NH2-terminal kinase. Microbes Infect 2007; 9:1410-4. [PMID: 17913539 DOI: 10.1016/j.micinf.2007.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Revised: 05/11/2007] [Accepted: 07/11/2007] [Indexed: 10/23/2022]
Abstract
Chlamydophila pneumoniae is known to be associated with atherosclerosis. Recent studies have reported that components of Chlamydophila pneumoniae (chlamydophilal antigens) induce foam cell formation in macrophages. However, the mechanism of foam cell formation induced by chlamydophilal antigens has yet to be elucidated. In this paper, we first found that mitogen-activated protein kinases including extracellular signal-regulated kinase, p38 and c-Jun NH2 terminal kinase are phosphorylated after stimulation by chlamydophilal antigens. We then showed that chlamydophilal antigens induce foam cell formation mainly via c-Jun NH2 terminal kinase. Finally, we demonstrated that foam cell formation and phosphorylation of mitogen-activated protein kinases induced by chlamydophilal antigens are mainly recognized through Toll-like receptor 2. These results collectively indicated that chlamydophilal antigens induce foam cell formation mainly via Toll-like receptor 2 and c-Jun NH2 terminal kinase.
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Affiliation(s)
- Takatoshi Kitazawa
- Department of Infectious Diseases, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
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25
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Zaharik ML, Nayar T, White R, Ma C, Vallance BA, Straka N, Jiang X, Rey-Ladino J, Shen C, Brunham RC. Genetic profiling of dendritic cells exposed to live- or ultraviolet-irradiated Chlamydia muridarum reveals marked differences in CXC chemokine profiles. Immunology 2006; 120:160-72. [PMID: 17073942 PMCID: PMC2265850 DOI: 10.1111/j.1365-2567.2006.02488.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Chlamydia trachomatis is a major cause of sexually transmitted disease worldwide for which an effective vaccine is being actively pursued. Current vaccine efforts will be aided by elucidating the interaction between Chlamydia and dendritic cells (DCs). Protective immunity appears to develop slowly following natural infection in humans, and early vaccine trials using inactivated C. trachomatis resulted in partial, short-lived protection with possible enhanced inflammatory pathology during re-infection. Thus, immunity following natural infection with live chlamydia may differ fundamentally from immune responses induced by immunization with inactivated chlamydia. We explored this conjecture by studying the response of DCs exposed to either viable or inactivated [ultraviolet (UV) -irradiated] chlamydia elementary bodies (EBs; designated as Live-EB and UV-EB, respectively) using Affymetrix GeneChip microarrays. Thirty-one immunologically characterized genes were differentially expressed by DCs following exposure to Live-EB or UV-EB, including two glutamic acid-leucine-arginine cysteine-X-cysteine (ELR CXC) neutrophil chemoattractant chemokines, Cxcl1 (KC), and Cxcl2 (MIP-2). Up-regulation of these genes by Live-EB as compared to UV-EB was verified by quantitative reverse transcription-polymerase chain reaction and increased chemokine secretion was confirmed by enzyme-linked immunosorbent assay both in vitro and in vivo. Immunofluorescence and fluorescence-activated cell sorter analysis of chlamydia-infected lung tissue confirmed that Live-EB but not UV-EB induced significant DC and neutrophil infiltration during infection. These observations demonstrate that the development of an antichlamydial immune response is dramatically influenced by chlamydial viability. This has implications as to why early inactivated chlamydial vaccines were ineffective and suggests that new vaccine design efforts may benefit from in vitro DC screening for ELR chemokine expression profiles.
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Affiliation(s)
- Michelle L Zaharik
- University of British Columbia Centre for Disease Control, Vancouver, BC, Canada
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26
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Müller-Loennies S, Gronow S, Brade L, MacKenzie R, Kosma P, Brade H. A monoclonal antibody against a carbohydrate epitope in lipopolysaccharide differentiates Chlamydophila psittaci from Chlamydophila pecorum, Chlamydophila pneumoniae, and Chlamydia trachomatis. Glycobiology 2005; 16:184-96. [PMID: 16282606 DOI: 10.1093/glycob/cwj055] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Lipopolysaccharide (LPS) of Chlamydophila psittaci but not of Chlamydophila pneumoniae or Chlamydia trachomatis contains a tetrasaccharide of 3-deoxy-alpha-d-manno-oct-2-ulopyranosonic acid (Kdo) of the sequence Kdo(2-->8)[Kdo(2-->4)] Kdo(2-->4)Kdo. After immunization with the synthetic neoglycoconjugate antigen Kdo(2-->8)[Kdo(2-->4)]Kdo(2-->4) Kdo-BSA, we obtained the mouse monoclonal antibody (mAb) S69-4 which was able to differentiate C. psittaci from Chlamydophila pecorum, C. pneumoniae, and C. trachomatis in double labeling experiments of infected cell monolayers and by enzyme-linked immunosorbent assay (ELISA). The epitope specificity of mAb S69-4 was determined by binding and inhibition assays using bacteria, LPS, and natural or synthetic Kdo oligosaccharides as free ligands or conjugated to BSA. The mAb bound preferentially Kdo(2-->8)[Kdo(2-->4)]Kdo(2-->4)Kdo(2-->4) with a K(d) of 10 microM, as determined by surface plasmon resonance (SPR) for the monovalent interaction using mAb or single chain Fv. Cross-reactivity was observed with Kdo(2-->4)Kdo(2-->4) Kdo but not with Kdo(2-->8)Kdo(2-->4)Kdo, Kdo disaccharides in 2-->4- or 2-->8-linkage, or Kdo monosaccharide. MAb S69-4 was able to detect LPS on thin-layer chromatography (TLC) plates in amounts of <10 ng by immunostaining. Due to the high sensitivity achieved in this assay, the antibody also detected in vitro products of cloned Kdo transferases of Chlamydia. The antibody can therefore be used in medical and veterinarian diagnostics, general microbiology, analytical biochemistry, and studies of chlamydial LPS biosynthesis. Further contribution to the general understanding of carbohydrate-binding antibodies was obtained by a comparison of the primary structure of mAb S69-4 to that of mAb S45-18 of which the crystal structure in complex with its ligand has been elucidated recently (Nguyen et al., 2003, Nat. Struct. Biol., 10, 1019-1025).
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Affiliation(s)
- Sven Müller-Loennies
- Research Center Borstel, Leibniz Center for Medicine and Biosciences, Parkallee 22, D-23845 Borstel, Germany
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27
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Gomes JP, Hsia RC, Mead S, Borrego MJ, Dean D. Immunoreactivity and differential developmental expression of known and putative Chlamydia trachomatis membrane proteins for biologically variant serovars representing distinct disease groups. Microbes Infect 2005; 7:410-20. [PMID: 15784185 DOI: 10.1016/j.micinf.2004.11.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Accepted: 11/20/2004] [Indexed: 10/25/2022]
Abstract
Chlamydia trachomatis is an intracellular bacterium that causes ocular and urogenital diseases worldwide. Membrane proteins have only been partially characterized, and the discovery of a nine-member polymorphic membrane protein gene family has enhanced interest in defining their function. We previously reported two putative insertion sequence-like elements in pmpC for biovariant Ba and one each for G and L2, suggesting horizontal gene transfer. Because of this and the tissue tropism differences for these biovariants, we analyzed by quantitative real-time RT-PCR pmpC expression relative to immunogenic protein genes ompA, groEL and gseA throughout development. Sera from infected adolescents were reacted by immunoblot against recombinant (r)PmpC and rMOMP. ompA and groEL revealed different developmental transcriptome profiles among the biovariants. pmpC expression occurred at 2 h, peaked at 18 for L2 (at 24 for Ba and G), with the highest mRNA levels throughout development for L2. pmpC expression as a function of time paralleled ompA expression with higher mRNA levels compared with groEL later in development. Only sera from D-, E- and G-infected patients reacted to rPmpC; all infected patients reacted to rMOMP. pmpC expression during logarithmic growth suggests a role in membrane building and/or integrity, which is supported by the presence of a signal peptidase and C-terminal phenylalanine in PmpC. Because phylogenetic analyses of pmpC segregate serovars according to tissue tropism, we speculate that biovariant transcriptome differences may contribute to this tropism. The heterogeneous biovariant pmpC expression throughout development and differential PmpC immunoreactivity also suggest a role for pmpC in antigenic variation.
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Affiliation(s)
- João P Gomes
- Department of Bacteriology, National Institute of Health, Avenue Padre Cruz, 1649-016 Lisbon, Portugal
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Stoll LL, Denning GM, Weintraub NL. Potential Role of Endotoxin as a Proinflammatory Mediator of Atherosclerosis. Arterioscler Thromb Vasc Biol 2004; 24:2227-36. [PMID: 15472123 DOI: 10.1161/01.atv.0000147534.69062.dc] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Atherosclerosis is increasingly recognized as a chronic inflammatory disease. Although a variety of inflammatory markers (ie, C-reactive protein) have been associated with atherosclerosis and its consequences, it is important to identify principal mediators of the inflammatory responses. One potentially important source of vascular inflammation in atherosclerosis is bacterial endotoxin. Mutations in Toll-like receptor 4 (TLR-4), an integral component of the endotoxin signaling complex, are fairly common in the Caucasian population and have recently been associated with reduced incidence of atherosclerosis and other cardiovascular diseases in some studies. Moreover, epidemiological studies suggest that endotoxemia at levels as low as 50 pg/mL constitutes a strong risk factor for the development of atherosclerosis. Endotoxin concentrations in this range may be produced by a variety of common subclinical Gram-negative infections. In this article, we outline the main elements of the endotoxin signaling receptor complex that initiates proinflammatory signaling (lipopolysaccharide binding protein [LBP], CD14, TLR-4, and MD-2) and discuss how changes in expression of these molecules may affect proatherogenic responses in the vessel wall. We also describe some of the proinflammatory effects of endotoxin that may be relevant to atherosclerosis, and discuss how serum lipoproteins, especially high-density lipoprotein, may modulate endotoxin-induced inflammatory responses. Further, we discuss recent findings suggesting that the lipid-lowering statins may have an additional protective role in blocking at least some of these proinflammatory signaling pathways. Finally, we discuss species diversity with regard to endotoxin signaling that should be considered when extrapolating experimental data from animal models to humans.
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Affiliation(s)
- Lynn L Stoll
- Department of Internal Medicine, Division of Cardiovascular Diseases, University of Iowa, Iowa City and The VA Medical Center, IA 52242, USA.
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Oberley RE, Goss KL, Ault KA, Crouch EC, Snyder JM. Surfactant protein D is present in the human female reproductive tract and inhibits Chlamydia trachomatis infection. ACTA ACUST UNITED AC 2004; 10:861-70. [PMID: 15489244 DOI: 10.1093/molehr/gah117] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Surfactant protein D (SP-D) is a lung collectin involved in innate host defence mechanisms in the lung. SP-D is also expressed at other mucosal sites throughout the human body. In the present study, we show that SP-D mRNA and protein are expressed in the human female reproductive tract. SP-D protein was localized in the apical portion of the reproductive epithelial cells. We also demonstrate that endometrial and endocervical cell lines and primary endocervical cells in culture produce SP-D mRNA and protein. Chlamydia trachomatis is an intracellular pathogen that infects the female reproductive tract, primarily the cervix, and is responsible for the most prevalent infectious disease in the USA. Untreated chlamydial infections of the female reproductive tract often result in sterility of the infected woman. Since SP-D protein is produced in cervical glands, we examined the effect of SP-D on chlamydial infection of cervical epithelial cells in vitro. We found that SP-D protein inhibits the infection of HeLa cells (an endocervical epithelial cell line) by C. trachomatis in a dose-dependent manner. We further demonstrate that the SP-D lectin-binding domain is involved in inhibiting infection of HeLa cells by Chlamydia. In conclusion, we detected SP-D in the female reproductive tract and determined that one of the functions of the SP-D protein may be to protect cervical epithelial cells from infection by C. trachomatis.
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Affiliation(s)
- Rebecca E Oberley
- Department of Anatomy and Cell Biology, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA
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Oberley RE, Ault KA, Neff TL, Khubchandani KR, Crouch EC, Snyder JM. Surfactant proteins A and D enhance the phagocytosis of Chlamydia into THP-1 cells. Am J Physiol Lung Cell Mol Physiol 2004; 287:L296-306. [PMID: 15075250 DOI: 10.1152/ajplung.00440.2003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chlamydiae are intracellular bacterial pathogens that infect mucosal surfaces, i.e., the epithelium of the lung, genital tract, and conjunctiva of the eye, as well as alveolar macrophages. In the present study, we show that pulmonary surfactant protein A (SP-A) and surfactant protein D (SP-D), lung collectins involved in innate host defense, enhance the phagocytosis of Chlamydia pneumoniae and Chlamydia trachomatis by THP-1 cells, a human monocyte/macrophage cell line. We also show that SP-A is able to aggregate both C. trachomatis and C. pneumoniae but that SP-D only aggregates C. pneumoniae. In addition, we found that after phagocytosis in the presence of SP-A, the number of viable C. trachomatis pathogens in the THP-1 cells 48 h later was increased approximately 3.5-fold. These findings suggest that SP-A and SP-D interact with chlamydial pathogens and enhance their phagocytosis into macrophages. In addition, the chlamydial pathogens internalized in the presence of collectins are able to grow and replicate in the THP-1 cells after phagocytosis.
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Affiliation(s)
- Rebecca E Oberley
- Department of Anatomy and Cell Biology, University of Iowa College of Medicine, Iowa City, IA 52242, USA
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van Zandbergen G, Gieffers J, Kothe H, Rupp J, Bollinger A, Aga E, Klinger M, Brade H, Dalhoff K, Maass M, Solbach W, Laskay T. Chlamydia pneumoniaeMultiply in Neutrophil Granulocytes and Delay Their Spontaneous Apoptosis. THE JOURNAL OF IMMUNOLOGY 2004; 172:1768-76. [PMID: 14734760 DOI: 10.4049/jimmunol.172.3.1768] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The obligate intracellular bacterial pathogen Chlamydia pneumoniae (Cp) is responsible for a range of human diseases, including acute respiratory infection. Although experimental intratracheal infection with Cp results in a massive recruitment of neutrophil granulocytes (polymorphonuclear neutrophils (PMN)), the role of these cells in the defense against Cp is unclear. In this study the interactions of PMN with Cp were investigated. In vitro coincubation experiments showed that human granulocytes were able to internalize Chlamydia in an opsonin-independent manner. Importantly, phagocytosed Cp were not killed; the ingested bacteria survived and multiplied within PMN. Although uninfected granulocytes became apoptotic within 10 h, infected PMN survived up to 90 h. Coincubation with Cp significantly decreased the ratio of apoptotic PMN, as detected by morphological analysis, annexin V, and TUNEL staining. The observed antiapoptotic effect was associated with a markedly lower level of procaspase-3 processing and, consequently, reduced caspase-3 activity in infected PMN. LPS was found as a major, but not exclusive, component responsible for the observed antiapoptotic effect. Chlamydia LPS affected PMN apoptosis both by acting directly on the cells and by inducing the autocrine production of the antiapoptotic cytokine IL-8. These data show that, in contrast to other microbial pathogens that drive phagocytes into apoptosis to escape killing, Cp can extend the life span of neutrophil granulocytes, making them suitable host cells for survival and multiplication within the first hours/days after infection.
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Affiliation(s)
- Ger van Zandbergen
- Institute for Medical Microbiology and Hygiene, University of Lübeck, Lübeck, Germany.
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32
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Abstract
The lipopolysaccharides of Gram-negative bacteria have a profound effect on the mammalian immune system and are of great significance in the pathophysiology of many disease processes. Consideration is given in this review to the relationship between structure and function of these lipopolysaccharides.
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Affiliation(s)
- Clett Erridge
- Medical Microbiology, University of Edinburgh Medical School, Edinburgh, Scotland, EH8 9AG, UK
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Shaw J, Grund V, Durling L, Crane D, Caldwell HD. Dendritic cells pulsed with a recombinant chlamydial major outer membrane protein antigen elicit a CD4(+) type 2 rather than type 1 immune response that is not protective. Infect Immun 2002; 70:1097-105. [PMID: 11854188 PMCID: PMC127771 DOI: 10.1128/iai.70.3.1097-1105.2002] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chlamydia trachomatis is an obligate intracellular bacterium that infects the oculogenital mucosae. C. trachomatis infection of the eye causes trachoma, the leading cause of preventable blindness. Infections of the genital mucosae are a leading cause of sexually transmitted diseases. A vaccine to prevent chlamydial infection is needed but has proven difficult to produce by using conventional vaccination approaches. Potent immunity to vaginal rechallenge in a murine model of chlamydial genital infection has been achieved only by infection or by immunization with dendritic cells (DC) pulsed ex vivo with whole inactivated organisms. Immunity generated by infection or ex vivo antigen-pulsed DC correlates with a chlamydia-specific interleukin 12 (IL-12)-dependent CD4(+) Th1 immune response. Because of the potent antichlamydial immunizing properties of DC, we hypothesized that DC could be a powerful vehicle for the delivery of individual chlamydial antigens that are thought to be targets for more conventional vaccine approaches. Here, we investigated the recombinant chlamydial major outer membrane protein (rMOMP) as a target antigen. The results demonstrate that DC pulsed with rMOMP secrete IL-12 and stimulate infection-sensitized CD4(+) T cells to proliferate and secrete gamma interferon. These immunological properties implied that rMOMP-pulsed DC would be potent inducers of MOMP-specific CD4(+) Th1 immunity in vivo; however, we observed the opposite result. DC pulsed ex vivo with rMOMP and adoptively transferred to naive mice generated a Th2 rather than a Th1 anti-MOMP immune response, and immunized mice were not protected following infectious challenge. We conclude from these studies that the immunological properties of ex vivo pulsed DC are not necessarily predictive of the immune response generated in vivo following adoptive transfer. These findings suggest that the nature of the antigen used to pulse DC ex vivo influences the Th1-Th2 balance of the immune response in vivo.
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Affiliation(s)
- Jennifer Shaw
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, USA
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King LE, Stratton CW, Mitchell WM. Chlamydia pneumoniae and chronic skin wounds: a focused review. J Investig Dermatol Symp Proc 2001; 6:233-7. [PMID: 11924834 DOI: 10.1046/j.0022-202x.2001.00050.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The genus, Chlamydophilia, as obligate intracellular pathogens, induce chronic scarring in humans. Chlamydia pneumoniae, a common cause of pneumonia, infects endothelial cells and circulating macrophages. Evidence that C. pneumoniae is an opportunistic pathogen in chronic skin ulcers and other inflammatory skin conditions analogous to its role in atherosclerosis is reviewed.
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Affiliation(s)
- L E King
- Department of Medicine (Dermatology), Nashville Veterans Administration Medical Centers, Tennessee, USA.
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Shaw JH, Grund VR, Durling L, Caldwell HD. Expression of genes encoding Th1 cell-activating cytokines and lymphoid homing chemokines by chlamydia-pulsed dendritic cells correlates with protective immunizing efficacy. Infect Immun 2001; 69:4667-72. [PMID: 11402013 PMCID: PMC98546 DOI: 10.1128/iai.69.7.4667-4672.2001] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We studied the expression of cytokines, chemokines, and chemokine receptors by the RNase protection assay in chlamydia-pulsed dendritic cells to better understand their potent anti-chlamydial immunizing properties. We found that chlamydia-pulsed dendritic cells express a complex profile of inflammatory and immunomodulatory molecules. These include CCR-7, interleukin-12, and interferon-induced protein 10, molecules that might influence the homing of pulsed dendritic cells to the site of chlamydial infection and the induction of a local protective CD4(+) Th1 cellular immunity.
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Affiliation(s)
- J H Shaw
- Laboratory of Intercellular Parasites, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratory, Hamilton, Montana 59840, USA
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