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de Jong H, Moure MJ, Hartman JEM, Bosman GP, Ong JY, Bardoel BW, Boons G, Wösten MMSM, Wennekes T. Selective Exoenzymatic Labeling of Lipooligosaccharides of Neisseria gonorrhoeae with α2,6-Sialoside Analogues. Chembiochem 2022; 23:e202200340. [PMID: 35877976 PMCID: PMC9804176 DOI: 10.1002/cbic.202200340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/23/2022] [Indexed: 01/05/2023]
Abstract
The interactions between bacteria and their host often rely on recognition processes that involve host or bacterial glycans. Glycoengineering techniques make it possible to modify and study the glycans on the host's eukaryotic cells, but only a few are available for the study of bacterial glycans. Here, we have adapted selective exoenzymatic labeling (SEEL), a chemical reporter strategy, to label the lipooligosaccharides of the bacterial pathogen Neisseria gonorrhoeae, using the recombinant glycosyltransferase ST6Gal1, and three synthetic CMP-sialic acid derivatives. We show that SEEL treatment does not affect cell viability and can introduce an α2,6-linked sialic acid with a reporter group on the lipooligosaccharides by Western blot, flow cytometry and fluorescent microscopy. This new bacterial glycoengineering technique allows for the precise modification, here with α2,6-sialoside derivatives, and direct detection of specific surface glycans on live bacteria, which will aid in further unravelling the precise biological functions of bacterial glycans.
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Affiliation(s)
- Hanna de Jong
- Department of Chemical Biology and Drug Discovery Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomedical ResearchUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands,Department of Biomolecular Health SciencesUtrecht UniversityYalelaan 13584 CLUtrechtThe Netherlands
| | - Maria J. Moure
- Complex Carbohydrate Research Center and Department of ChemistryUniversity of Georgia315 Riverbend RoadAthensGA 30602USA,Chemical Glycobiology Lab, CIC bioGUNEBasque Research & Technology Alliance (BRTA)Bizkaia Technology Park, Building 80048160DerioSpain
| | - Jet E. M. Hartman
- Department of Chemical Biology and Drug Discovery Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomedical ResearchUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
| | - Gerlof P. Bosman
- Department of Chemical Biology and Drug Discovery Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomedical ResearchUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
| | - Jun Yang Ong
- Department of Chemical Biology and Drug Discovery Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomedical ResearchUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
| | - Bart W. Bardoel
- Department of Medical MicrobiologyUniversity Medical Center UtrechtHeidelberglaan 100 HP G04.6143584 CXUtrechtThe Netherlands
| | - Geert‐Jan Boons
- Department of Chemical Biology and Drug Discovery Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomedical ResearchUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands,Complex Carbohydrate Research Center and Department of ChemistryUniversity of Georgia315 Riverbend RoadAthensGA 30602USA
| | - Marc M. S. M. Wösten
- Department of Biomolecular Health SciencesUtrecht UniversityYalelaan 13584 CLUtrechtThe Netherlands
| | - Tom Wennekes
- Department of Chemical Biology and Drug Discovery Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomedical ResearchUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
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Matthias KA, Connolly KL, Begum AA, Jerse AE, Macintyre AN, Sempowski GD, Bash MC. Meningococcal Detoxified Outer Membrane Vesicle Vaccines Enhance Gonococcal Clearance in a Murine Infection Model. J Infect Dis 2021; 225:650-660. [PMID: 34498079 DOI: 10.1093/infdis/jiab450] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 09/08/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Despite decades of research efforts, development of a gonorrhea vaccine has remained elusive. Epidemiological studies suggest that detoxified outer membrane vesicle (dOMV) vaccines from Neisseria meningitidis (Nm) may protect against infection with Neisseria gonorrhoeae (Ng). We recently reported that Nm dOMVs lacking the major outer membrane proteins (OMPs) PorA, PorB, and RmpM induced greater antibody cross-reactivity against heterologous Nm strains than wild-type (WT) dOMVs and may represent an improved vaccine against gonorrhea. METHODS We prepared dOMV vaccines from meningococcal strains that were sufficient or deleted for PorA, PorB, and RmpM. Vaccines were tested in a murine genital tract infection model and antisera were used to identify vaccine targets. RESULTS Immunization with Nm dOMVs significantly and reproducibly enhanced gonococcal clearance for mice immunized with OMP-deficient dOMVs; significant clearance for WT dOMV-immunized mice was observed in one of two experiments. Clearance was associated with serum and vaginal anti-Nm dOMV IgG antibodies that cross-reacted with Ng. Serum IgG was used to identify putative Ng vaccine targets, including PilQ, MtrE, NlpD, and GuaB. CONCLUSIONS Meningococcal dOMVs elicited a protective effect against experimental gonococcal infection. Recognition and identification of Ng vaccine targets by Nm dOMV-induced antibodies supports the development of a cross-protective Neisseria vaccine.
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Affiliation(s)
- Kathryn A Matthias
- Laboratory of Bacterial Polysaccharides, Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, USA
| | - Kristie L Connolly
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Afrin A Begum
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Ann E Jerse
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Andrew N Macintyre
- Duke Human Vaccine Institute and Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Gregory D Sempowski
- Duke Human Vaccine Institute and Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Margaret C Bash
- Laboratory of Bacterial Polysaccharides, Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, USA
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3
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Russell MW. Immune Responses to Neisseria gonorrhoeae: Challenges and Opportunities With Respect to Pelvic Inflammatory Disease. J Infect Dis 2021; 224:S96-S102. [PMID: 34396399 DOI: 10.1093/infdis/jiaa766] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Pelvic inflammatory disease and infertility frequently develop after female genital tract infection with Neisseria gonorrhoeae, but determining their etiology from among various possibilities presents difficulties. Exploitation of serology to identify the causative agent is complicated by numerous factors, and no immunological test currently exists to determine unequivocally whether an individual currently is, or has been, infected with N. gonorrhoeae. The extensive antigenic variability of N. gonorrhoeae and its expression of antigens shared with other Neisseria species commonly carried in humans render problematic an assay that is specific for all gonococcal strains. However, novel conserved gonococcal antigens identified for potential vaccines may find additional application in diagnostic assays. N. gonorrhoeae also interferes with the adaptive immune response, and antibody responses to uncomplicated infection are usually weak. Elucidating the mechanisms whereby N. gonorrhoeae manipulates the human immune system may lead to improved understanding of the pathogenesis of pelvic inflammatory disease and infertility.
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Affiliation(s)
- Michael W Russell
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
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Distinct Patterns of Host Adherence by Neisseria gonorrhoeae Isolated from Experimental Gonorrhea. ACTA ACUST UNITED AC 2021; 2021:7865405. [PMID: 34093925 PMCID: PMC8140856 DOI: 10.1155/2021/7865405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 03/30/2021] [Accepted: 04/03/2021] [Indexed: 12/29/2022]
Abstract
Neisseria gonorrhoeae (N. gonorrhoeae, gonococci, or GC), the etiologic agent of gonorrhea, is a human-obligate bacterial pathogen. The GC surface contains pili that mediate the adherence to host cells. Studies have shown that GC pili, coded by pilin genes, undergo remarkable changes during human experimental gonorrhea, possibly generated by DNA phase variation during infection. The question that arises is whether the changes in pilins can alter the adherence capacity of N. gonorrhoeae to host cells. In this study, six variants initially isolated from male volunteers infected with one single clone of GC were examined for their adherence patterns with human Chang conjunctiva cells. In this study, we showed that the variants showed distinct adherence patterns to this cell line under light microscopy and scanning electron microscopy. Moreover, two reisolates showed higher adherence capacities than that of the input strain. The results provide an additional example as to how the pilus variation may play a role in the pathogenesis of N. gonorrhoeae.
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Jefferson A, Smith A, Fasinu PS, Thompson DK. Sexually Transmitted Neisseria gonorrhoeae Infections-Update on Drug Treatment and Vaccine Development. MEDICINES 2021; 8:medicines8020011. [PMID: 33562607 PMCID: PMC7914478 DOI: 10.3390/medicines8020011] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/17/2021] [Accepted: 02/03/2021] [Indexed: 12/15/2022]
Abstract
Background: Sexually transmitted gonorrhea, caused by the Gram-negative diplococcus Neisseria gonorrhoeae, continues to be a serious global health challenge despite efforts to eradicate it. Multidrug resistance among clinical N. gonorrhoeae isolates has limited treatment options, and attempts to develop vaccines have not been successful. Methods: A search of published literature was conducted, and information extracted to provide an update on the status of therapeutics and vaccine development for gonorrheal infection. Results: Recommended pharmacological treatment for gonorrhea has changed multiple times due to increasing acquisition of resistance to existing antibiotics by N. gonorrhoeae. Only broad-spectrum cephalosporin-based combination therapies are currently recommended for treatment of uncomplicated urogenital and anorectal gonococcal infections. With the reported emergence of ceftriaxone resistance, successful strategies addressing the global burden of gonorrhea must include vaccination. Century-old efforts at developing an effective vaccine against gonorrhea, leading to only four clinical trials, have not yielded any successful vaccine. Conclusions: While it is important to continue to explore new drugs for the treatment of gonorrhea, the historical trend of resistance acquisition suggests that any long-term strategy should include vaccine development. Advanced technologies in proteomics and in silico approaches to vaccine target identification may provide templates for future success.
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Affiliation(s)
- Amber Jefferson
- School of Pharmacy, College of Pharmacy & Health Sciences, Campbell University, Buies Creek, NC 27506, USA; (A.J.); (A.S.)
| | - Amanda Smith
- School of Pharmacy, College of Pharmacy & Health Sciences, Campbell University, Buies Creek, NC 27506, USA; (A.J.); (A.S.)
| | - Pius S. Fasinu
- Department of Pharmaceutical Sciences, College of Pharmacy & Health Sciences, Campbell University, Buies Creek, NC 27506, USA;
| | - Dorothea K. Thompson
- Department of Pharmaceutical Sciences, College of Pharmacy & Health Sciences, Campbell University, Buies Creek, NC 27506, USA;
- Correspondence: ; Tel.: +1-910-893-7463
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Lim KYL, Mullally CA, Haese EC, Kibble EA, McCluskey NR, Mikucki EC, Thai VC, Stubbs KA, Sarkar-Tyson M, Kahler CM. Anti-Virulence Therapeutic Approaches for Neisseria gonorrhoeae. Antibiotics (Basel) 2021; 10:antibiotics10020103. [PMID: 33494538 PMCID: PMC7911339 DOI: 10.3390/antibiotics10020103] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 01/15/2023] Open
Abstract
While antimicrobial resistance (AMR) is seen in both Neisseria gonorrhoeae and Neisseria meningitidis, the former has become resistant to commonly available over-the-counter antibiotic treatments. It is imperative then to develop new therapies that combat current AMR isolates whilst also circumventing the pathways leading to the development of AMR. This review highlights the growing research interest in developing anti-virulence therapies (AVTs) which are directed towards inhibiting virulence factors to prevent infection. By targeting virulence factors that are not essential for gonococcal survival, it is hypothesized that this will impart a smaller selective pressure for the emergence of resistance in the pathogen and in the microbiome, thus avoiding AMR development to the anti-infective. This review summates the current basis of numerous anti-virulence strategies being explored for N. gonorrhoeae.
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Affiliation(s)
- Katherine Y. L. Lim
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Christopher A. Mullally
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Ethan C. Haese
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Emily A. Kibble
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150, Australia
| | - Nicolie R. McCluskey
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150, Australia
| | - Edward C. Mikucki
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Van C. Thai
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Keith A. Stubbs
- School of Molecular Sciences, University of Western Australia, Crawley, WA 6009, Australia;
| | - Mitali Sarkar-Tyson
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Charlene M. Kahler
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
- Correspondence:
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Russell MW, Jerse AE, Gray-Owen SD. Progress Toward a Gonococcal Vaccine: The Way Forward. Front Immunol 2019; 10:2417. [PMID: 31681305 PMCID: PMC6803597 DOI: 10.3389/fimmu.2019.02417] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 09/27/2019] [Indexed: 12/26/2022] Open
Abstract
The concept of immunizing against gonorrhea has received renewed interest because of the recent emergence of strains of Neisseria gonorrhoeae that are resistant to most currently available antibiotics, an occurrence that threatens to render gonorrhea untreatable. However, despite efforts over many decades, no vaccine has yet been successfully developed for human use, leading to pessimism over whether this goal was actually attainable. Several factors have contributed to this situation, including extensive variation of the expression and specificity of many of the gonococcal surface antigens, and the ability of N. gonorrhoeae to resist destruction by complement and other innate immune defense mechanisms. The natural host restriction of N. gonorrhoeae for humans, coupled with the absence of any definable state of immunity arising from an episode of gonorrhea, have also complicated efforts to study gonococcal pathogenesis and the host's immune responses. However, recent findings have elucidated how the gonococcus exploits and manipulates the host's immune system for its own benefit, utilizing human-specific receptors for attachment to and invasion of tissues, and subverting adaptive immune responses that might otherwise be capable of eliminating it. While no single experimental model is capable of providing all the answers, experiments utilizing human cells and tissues in vitro, various in vivo animal models, including genetically modified strains of mice, and both experimental and observational human clinical studies, have combined to yield important new insight into the immuno-pathogenesis of gonococcal infection. In turn, these have now led to novel approaches for the development of a gonococcal vaccine. Ongoing investigations utilizing all available tools are now poised to make the development of an effective human vaccine against gonorrhea an achievable goal within a foreseeable time-frame.
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Affiliation(s)
- Michael W. Russell
- Department of Microbiology and Immunology, University at Buffalo, Buffalo, NY, United States
| | - Ann E. Jerse
- Department of Microbiology and Immunology, F. Edward Herbert School of Medicine, Uniformed Services University, Bethesda, MD, United States
| | - Scott D. Gray-Owen
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
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Uptake of Sialic Acid by Nontypeable Haemophilus influenzae Increases Complement Resistance through Decreasing IgM-Dependent Complement Activation. Infect Immun 2019; 87:IAI.00077-19. [PMID: 30936154 DOI: 10.1128/iai.00077-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 03/21/2019] [Indexed: 01/15/2023] Open
Abstract
Although nontypeable Haemophilus influenzae (NTHi) is a human-specific nasopharyngeal commensal bacterium, it also causes upper respiratory tract infections in children and lower respiratory tract infections in the elderly, resulting in frequent antibiotic use. The transition from symbiotic colonizing bacterium to opportunistic pathogen is not completely understood. Incorporation of sialic acids into lipooligosaccharides is thought to play an important role in bacterial virulence. It has been known for more than 25 years that sialic acids increase resistance to complement-mediated killing; however, the mechanism of action has not been elucidated thus far. Here, we provide evidence that growth of NTHi in the presence of sialic acids Neu5Ac and Neu5Gc decreases complement-mediated killing through abrogating the classical pathway of complement activation by preventing mainly IgM antibody binding to the bacterial surface. Therefore, strategies that interfere with uptake or incorporation of sialic acids into the lipooligosaccharide, such as novel antibiotics and vaccines, might be worth exploring to prevent or treat NTHi infections.
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Wei M, Wang PG. Desialylation in physiological and pathological processes: New target for diagnostic and therapeutic development. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2019; 162:25-57. [PMID: 30905454 DOI: 10.1016/bs.pmbts.2018.12.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Desialylation is a pivotal part of sialic acid metabolism, which initiates the catabolism of glycans by removing the terminal sialic acid residues on glycans, thereby modulating the structure and functions of glycans, glycoproteins, or glycolipids. The functions of sialic acids have been well recognized, whereas the function of desialylation process is underappreciated or largely ignored. However, accumulating evidence demonstrates that desialylation plays an important role in a variety of physiological and pathological processes. This chapter summarizes the current knowledge pertaining to desialylation in a variety of physiological and pathological processes, with a focus on the underlying molecular mechanisms. The potential of targeting desialylation process for diagnostic and therapeutic development is also discussed.
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Affiliation(s)
- Mohui Wei
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States.
| | - Peng George Wang
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, United States
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Abstract
Neisseria gonorrhoeae infection is a major public health problem worldwide. The increasing incidence of gonorrhea coupled with global spread of multidrug-resistant isolates of gonococci has ushered in an era of potentially untreatable infection. Gonococcal disease elicits limited immunity, and individuals are susceptible to repeated infections. In this chapter, we describe gonococcal disease and epidemiology and the structure and function of major surface components involved in pathogenesis. We also discuss the mechanisms that gonococci use to evade host immune responses and the immune responses following immunization with selected bacterial components that may overcome evasion. Understanding the biology of the gonococcus may aid in preventing the spread of gonorrhea and also facilitate the development of gonococcal vaccines and treatments.
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Affiliation(s)
- Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Peter A Rice
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA.
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Nontypeable Haemophilus influenzae Lipooligosaccharide Expresses a Terminal Ketodeoxyoctanoate In Vivo, Which Can Be Used as a Target for Bactericidal Antibody. mBio 2018; 9:mBio.01401-18. [PMID: 30065093 PMCID: PMC6069110 DOI: 10.1128/mbio.01401-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is an important pathogen in individuals of all ages. The lipooligosaccharide (LOS) of NTHi has evolved a complex structure that can be attributed to a multiplicity of glycosyltransferases, the random switching of glycosyltransferase gene expression via phase variation, and the complex structure of its core region with multiple glycoform branch points. This article adds to that complexity by describing a multifunctional enzyme (LsgB) which optimally functions when the species is grown on a solid surface and which can add either a ketodeoxyoctanoate (KDO) or an N-acetylneuramic acid (Neu5Ac) moiety to a terminal N-acetyllactosamine structure of LOS. Our studies show that expression of lsgB is reduced four- to sixfold when NTHi is grown in broth. The substrate that the enzyme utilizes is dependent upon the concentration of free Neu5Ac (between 1 and 10 µg/ml) in the environment. In environments in which Neu5Ac is below that level, the enzyme utilizes endogenous CMP-KDO as the substrate. Our studies show that during in vivo growth in an NTHi biofilm, the KDO moiety is expressed by the organism. Monoclonal antibody 6E4, which binds KDO, is bactericidal for NTHi strains that express the KDO epitope at high levels. In a survey of 33 NTHi strains isolated from healthy and diseased individuals, the antibody was bactericidal (>90% kill) for 12 strains (36%). These studies open up the possibility of using a KDO-based glycoconjugate vaccine as part of a multicomponent vaccine against NTHi.IMPORTANCE Nontypeable Haemophilus influenzae is an important pathogen in middle ear infections in children, sinusitis in adults, and acute bronchitis in individuals with chronic obstructive lung disease. The organism is very well adapted to the human host environment, and this has hindered successful development of an effective vaccine. In this article, we describe a mechanism by which the bacteria decorates its surface lipooligosaccharide with a sugar unique to Gram-negative bacteria, ketodeoxyoctanoate (KDO). This sugar decoration is present during active infection and we have shown that an antibody directed against this sugar can result in killing of the organism. These data demonstrate that the lipooligosaccharide ketodeoxyoctanoate epitope may be a novel NTHi-specific candidate vaccine antigen.
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A Novel Sialylation Site on Neisseria gonorrhoeae Lipooligosaccharide Links Heptose II Lactose Expression with Pathogenicity. Infect Immun 2018; 86:IAI.00285-18. [PMID: 29844237 DOI: 10.1128/iai.00285-18] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 05/22/2018] [Indexed: 01/15/2023] Open
Abstract
Sialylation of lacto-N-neotetraose (LNnT) extending from heptose I (HepI) of gonococcal lipooligosaccharide (LOS) contributes to pathogenesis. Previously, gonococcal LOS sialyltransterase (Lst) was shown to sialylate LOS in Triton X-100 extracts of strain 15253, which expresses lactose from both HepI and HepII, the minimal structure required for monoclonal antibody (MAb) 2C7 binding. Ongoing work has shown that growth of 15253 in cytidine monophospho-N-acetylneuraminic acid (CMP-Neu5Ac)-containing medium enables binding to CD33/Siglec-3, a cell surface receptor that binds sialic acid, suggesting that lactose termini on LOSs of intact gonococci can be sialylated. Neu5Ac was detected on LOSs of strains 15253 and an MS11 mutant with lactose only from HepI and HepII by mass spectrometry; deleting HepII lactose rendered Neu5Ac undetectable. Resistance of HepII lactose Neu5Ac to desialylation by α2-3-specific neuraminidase suggested an α2-6 linkage. Although not associated with increased factor H binding, HepII lactose sialylation inhibited complement C3 deposition on gonococci. Strain 15253 mutants that lacked Lst or HepII lactose were significantly attenuated in mice, confirming the importance of HepII Neu5Ac in virulence. All 75 minimally passaged clinical isolates from Nanjing, China, expressed HepII lactose, evidenced by reactivity with MAb 2C7; MAb 2C7 was bactericidal against the first 62 (of 75) isolates that had been collected sequentially and were sialylated before testing. MAb 2C7 effectively attenuated 15253 vaginal colonization in mice. In conclusion, this novel sialylation site could explain the ubiquity of gonococcal HepII lactose in vivo Our findings reinforce the candidacy of the 2C7 epitope as a vaccine antigen and MAb 2C7 as an immunotherapeutic antibody.
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Ram S, Shaughnessy J, de Oliveira RB, Lewis LA, Gulati S, Rice PA. Gonococcal lipooligosaccharide sialylation: virulence factor and target for novel immunotherapeutics. Pathog Dis 2017; 75:3777971. [PMID: 28460033 PMCID: PMC5449626 DOI: 10.1093/femspd/ftx049] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 04/26/2017] [Indexed: 12/13/2022] Open
Abstract
Gonorrhea has become resistant to most conventional antimicrobials used in clinical practice. The global spread of multidrug-resistant isolates of Neisseria gonorrhoeae could lead to an era of untreatable gonorrhea. New therapeutic modalities with novel mechanisms of action that do not lend themselves to the development of resistance are urgently needed. Gonococcal lipooligosaccharide (LOS) sialylation is critical for complement resistance and for establishing infection in humans and experimental mouse models. Here we describe two immunotherapeutic approaches that target LOS sialic acid: (i) a fusion protein that comprises the region in the complement inhibitor factor H (FH) that binds to sialylated gonococci and IgG Fc (FH/Fc fusion protein) and (ii) analogs of sialic acid that are incorporated into LOS but fail to protect the bacterium against killing. Both molecules showed efficacy in the mouse vaginal colonization model of gonorrhea and may represent promising immunotherapeutic approaches to target multidrug-resistant isolates. Disabling key gonococcal virulence mechanisms is an effective therapeutic strategy because the reduction of virulence is likely to be accompanied by a loss of fitness, rapid elimination by host immunity and consequently, decreased transmission.
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Affiliation(s)
- Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Rosane B. de Oliveira
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Lisa A. Lewis
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Sunita Gulati
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Peter A. Rice
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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Hill SA, Masters TL, Wachter J. Gonorrhea - an evolving disease of the new millennium. MICROBIAL CELL (GRAZ, AUSTRIA) 2016; 3:371-389. [PMID: 28357376 PMCID: PMC5354566 DOI: 10.15698/mic2016.09.524] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 01/30/2016] [Indexed: 12/21/2022]
Abstract
Etiology, transmission and protection: Neisseria gonorrhoeae (the gonococcus) is the etiological agent for the strictly human sexually transmitted disease gonorrhea. Infections lead to limited immunity, therefore individuals can become repeatedly infected. Pathology/symptomatology: Gonorrhea is generally a non-complicated mucosal infection with a pustular discharge. More severe sequellae include salpingitis and pelvic inflammatory disease which may lead to sterility and/or ectopic pregnancy. Occasionally, the organism can disseminate as a bloodstream infection. Epidemiology, incidence and prevalence: Gonorrhea is a global disease infecting approximately 60 million people annually. In the United States there are approximately 300, 000 cases each year, with an incidence of approximately 100 cases per 100,000 population. Treatment and curability: Gonorrhea is susceptible to an array of antibiotics. Antibiotic resistance is becoming a major problem and there are fears that the gonococcus will become the next "superbug" as the antibiotic arsenal diminishes. Currently, third generation extended-spectrum cephalosporins are being prescribed. Molecular mechanisms of infection: Gonococci elaborate numerous strategies to thwart the immune system. The organism engages in extensive phase (on/off switching) and antigenic variation of several surface antigens. The organism expresses IgA protease which cleaves mucosal antibody. The organism can become serum resistant due to its ability to sialylate lipooligosaccharide in conjunction with its ability to subvert complement activation. The gonococcus can survive within neutrophils as well as in several other lymphocytic cells. The organism manipulates the immune response such that no immune memory is generated which leads to a lack of protective immunity.
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Affiliation(s)
- Stuart A. Hill
- Department of Epidemiology, Gillings School of Global Public Health,
University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7435
| | - Thao L. Masters
- Department of Epidemiology, Gillings School of Global Public Health,
University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7435
| | - Jenny Wachter
- Department of Epidemiology, Gillings School of Global Public Health,
University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7435
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15
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Shafer WM. Does the Cervicovaginal Microbiome Facilitate Transmission of Neisseria gonorrhoeae From Women to Men? Implications for Understanding Transmission of Gonorrhea and Advancing Vaccine Development. J Infect Dis 2016; 214:1615-1617. [PMID: 27471316 DOI: 10.1093/infdis/jiw331] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 07/21/2016] [Indexed: 01/11/2023] Open
Affiliation(s)
- William M Shafer
- Department of Microbiology and Immunology.,Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta.,Medical Research Service, Veterans Affairs Medical Center, Decatur, Georgia
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16
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Ketterer MR, Rice PA, Gulati S, Kiel S, Byerly L, Fortenberry JD, Soper DE, Apicella MA. Desialylation of Neisseria gonorrhoeae Lipooligosaccharide by Cervicovaginal Microbiome Sialidases: The Potential for Enhancing Infectivity in Men. J Infect Dis 2016; 214:1621-1628. [PMID: 27471322 DOI: 10.1093/infdis/jiw329] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 07/07/2016] [Indexed: 12/22/2022] Open
Abstract
Previous studies have demonstrated that Neisseria gonorrhoeae sialylates the terminal N-acetyllactosamine present on its lipooligosaccharide (LOS) by acquiring CMP-N-acetyl-5-neuraminic acid upon entering human cells during infection. This renders the organism resistant to killing by complement in normal human serum. N-acetyllactosamine residues on LOS must be free of N-acetyl-5-neuraminc acid (Neu5Ac; also known as "sialic acid") in order for organisms to bind to and enter urethral epithelial cells during infection in men. This raises the question of how the gonococcus infects men if N-acetyllactosamine residues are substituted by Neu5Ac during infection in women. Here, we demonstrate that women with gonococcal infections have levels of sialidases present in cervicovaginal secretions that can result in desialylation of (sialylated) gonococcal LOS. The principle sialidases responsible for this desialylation appear to be bacterial in origin. These studies suggest that members of the cervicovaginal microbiome can modify N. gonorrhoeae, which will enhance successful transmission to men.
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Affiliation(s)
- Margaret R Ketterer
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City
| | - Peter A Rice
- Department of Medicine/Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester
| | - Sunita Gulati
- Department of Medicine/Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester
| | - Steven Kiel
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City
| | - Luke Byerly
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City
| | | | - David E Soper
- Division of Obstetric and Gynecologic Specialists, Medical College of South Carolina Hospital, Charleston
| | - Michael A Apicella
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City
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Ram S, Shaughnessy J, DeOliveira RB, Lewis LA, Gulati S, Rice PA. Utilizing complement evasion strategies to design complement-based antibacterial immunotherapeutics: Lessons from the pathogenic Neisseriae. Immunobiology 2016; 221:1110-23. [PMID: 27297292 DOI: 10.1016/j.imbio.2016.05.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 05/27/2016] [Indexed: 12/30/2022]
Abstract
Novel therapies are urgently needed to combat the global threat of multidrug-resistant pathogens. Complement forms an important arm of innate defenses against infections. In physiological conditions, complement activation is tightly controlled by soluble and membrane-associated complement inhibitors, but must be selectively activated on invading pathogens to facilitate microbial clearance. Many pathogens, including Neisseria gonorrhoeae and N. meningitidis, express glycans, including N-acetylneuraminic acid (Neu5Ac), that mimic host structures to evade host immunity. Neu5Ac is a negatively charged 9-cabon sugar that inhibits complement, in part by enhancing binding of the complement inhibitor factor H (FH) through C-terminal domains (19 and 20) on FH. Other microbes also bind FH, in most instances through FH domains 6 and 7 or 18-20. Here we describe two strategies to target complement activation on Neisseriae. First, microbial binding domains of FH were fused to IgG Fc to create FH18-20/Fc (binds gonococci) and FH6,7/Fc (binds meningococci). A point mutation in FH domain 19 eliminated hemolysis caused by unmodified FH18-20, but retained binding to gonococci. FH18-20/Fc and FH6,7/Fc mediated complement-dependent killing in vitro and showed efficacy in animal models of gonorrhea and meningococcal bacteremia, respectively. The second strategy utilized CMP-nonulosonate (CMP-NulO) analogs of sialic acid that were incorporated into LOS and prevented complement inhibition by physiologic CMP-Neu5Ac and resulted in attenuated gonococcal infection in mice. While studies to establish the safety of these agents are needed, enhancing complement activation on microbes may represent a promising strategy to treat antimicrobial resistant organisms.
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Affiliation(s)
- Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
| | - Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Rosane B DeOliveira
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Lisa A Lewis
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Sunita Gulati
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Peter A Rice
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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Matthias KA, Rest RF. Control of pili and sialyltransferase expression inNeisseria gonorrhoeaeis mediated by the transcriptional regulator CrgA. Mol Microbiol 2014; 91:1120-35. [DOI: 10.1111/mmi.12522] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2014] [Indexed: 01/15/2023]
Affiliation(s)
- Kathryn A. Matthias
- Department of Microbiology and Immunology; Drexel University College of Medicine; Philadelphia PA USA
| | - Richard F. Rest
- Department of Microbiology and Immunology; Drexel University College of Medicine; Philadelphia PA USA
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19
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Gonococci in vivo: Host CMP-NANA, sialylated lipopolysaccharide and serum resistance. Can J Infect Dis 2012; 4:31-7. [PMID: 22346417 DOI: 10.1155/1993/791512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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20
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Hobbs MM, Sparling PF, Cohen MS, Shafer WM, Deal CD, Jerse AE. Experimental Gonococcal Infection in Male Volunteers: Cumulative Experience with Neisseria gonorrhoeae Strains FA1090 and MS11mkC. Front Microbiol 2011; 2:123. [PMID: 21734909 PMCID: PMC3119411 DOI: 10.3389/fmicb.2011.00123] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 05/17/2011] [Indexed: 11/30/2022] Open
Abstract
Experimental infection of male volunteers with Neisseria gonorrhoeae is safe and reproduces the clinical features of naturally acquired gonococcal urethritis. Human inoculation studies have helped define the natural history of experimental infection with two well-characterized strains of N. gonorrhoeae, FA1090 and MS11mkC. The human model has proved useful for testing the importance of putative gonococcal virulence factors for urethral infection in men. Studies with isogenic mutants have improved our understanding of the requirements for gonococcal LOS structures, pili, opacity proteins, IgA1 protease, and the ability of infecting organisms to obtain iron from human transferrin and lactoferrin during uncomplicated urethritis. The model also presents opportunities to examine innate host immune responses that may be exploited or improved in development and testing of gonococcal vaccines. Here we review results to date with human experimental gonorrhea.
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Affiliation(s)
- Marcia M. Hobbs
- Departments of Medicine, University of North CarolinaChapel Hill, NC, USA
- Department of Microbiology and Immunology, University of North CarolinaChapel Hill, NC, USA
| | - P. Frederick Sparling
- Departments of Medicine, University of North CarolinaChapel Hill, NC, USA
- Department of Microbiology and Immunology, University of North CarolinaChapel Hill, NC, USA
| | - Myron S. Cohen
- Departments of Medicine, University of North CarolinaChapel Hill, NC, USA
- Department of Microbiology and Immunology, University of North CarolinaChapel Hill, NC, USA
| | - William M. Shafer
- Department of Microbiology and Immunology, Emory University School of MedicineAtlanta, GA, USA
- Laboratories of Bacterial Pathogenesis, Veterans Affairs Medical Center (Atlanta)Decatur, GA, USA
| | - Carolyn D. Deal
- National Institute of Allergy and Infectious Diseases, National Institutes of HealthBethesda, MD, USA
| | - Ann E. Jerse
- Department of Microbiology and Immunology, Uniformed Services University of the Health SciencesBethesda, MD, USA
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21
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Wu H, Jerse AE. Alpha-2,3-sialyltransferase enhances Neisseria gonorrhoeae survival during experimental murine genital tract infection. Infect Immun 2006; 74:4094-103. [PMID: 16790783 PMCID: PMC1489707 DOI: 10.1128/iai.00433-06] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The addition of host-derived sialic acid to Neisseria gonorrhoeae lipooligosaccharide is hypothesized to be an important mechanism by which gonococci evade host innate defenses. This hypothesis is based primarily on in vitro assays of complement-mediated and phagocytic killing. Here we report that a nonpolar alpha-2,3-sialyltransferase (lst) mutant of N. gonorrhoeae was significantly attenuated in its capacity to colonize the lower genital tract of 17-beta estradiol-treated female BALB/c mice during competitive infection with the wild-type strain. Genetic complementation of the lst mutation restored recovery of the mutant to wild-type levels. Studies with B10.D2-HC(o)H2(d)H(2)-T18c/OSN (C5-deficient) mice showed that attenuation of the lst mutant was not due to increased sensitivity to complement-mediated bacteriolysis, a result that is consistent with recently reported host restrictions in the complement cascade. However, Lst-deficient gonococci were killed more rapidly than sialylated wild-type gonococci following intraperitoneal injection into normal mice, which is consistent with sialylation conferring protection against killing by polymorphonuclear leukocytes (PMNs). As reported for human PMNs, sialylated gonococci were more resistant to killing by murine PMNs, and sialylation led to reduced association with and induction of a weaker respiratory burst in PMNs from estradiol-treated mice. In summary, these studies suggest sialylation confers a survival advantage to N. gonorrhoeae in mice by increasing resistance to PMN killing. This report is the first direct demonstration that alpha-2,3-sialyltransferase contributes to N. gonorrhoeae pathogenesis in an in vivo model. This study also validates the use of experimental murine infection to study certain aspects of gonococcal pathogenesis.
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Affiliation(s)
- Hong Wu
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Rd., Bethesda, MD 20814-4799, USA
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22
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Gulati S, Cox A, Lewis LA, Michael FS, Li J, Boden R, Ram S, Rice PA. Enhanced factor H binding to sialylated Gonococci is restricted to the sialylated lacto-N-neotetraose lipooligosaccharide species: implications for serum resistance and evidence for a bifunctional lipooligosaccharide sialyltransferase in Gonococci. Infect Immun 2005; 73:7390-7. [PMID: 16239538 PMCID: PMC1273834 DOI: 10.1128/iai.73.11.7390-7397.2005] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
We isolated serologically identical (by serovar determination and porin variable region [VR] typing) strains of Neisseria gonorrhoeae from an infected male and two of his monogamous female sex partners. One strain (termed 398078) expressed the L1 (Galalpha1 --> 4 [corrected] Galbeta1 --> 4Glcbeta1 --> 4HepI) lipooligosaccharide (LOS) structure exclusively; the other (termed 398079) expressed the lacto-N-neotetraose (LNT; Galbeta1 --> 4GlcNAcbeta1 --> 3Galbeta1 --> 4Glcbeta1 --> 4HepI) LOS structure. The strain from the male index case expressed both glycoforms and exhibited both immunotypes. Nuclear magnetic resonance analysis revealed that sialic acid linked to the terminal Gal of L1 LOS via an alpha2 --> 6 linkage and, as expected, to the terminal Gal of LNT LOS via an alpha2--> 3 linkage. Insertional inactivation of the sialyltransferase gene (known to sialylate LNT LOS) abrogated both L1 LOS sialylation and LNT LOS sialylation, suggesting a bifunctional nature of this enzyme in gonococci. Akin to our previous observations, sialylation of the LNT LOS of strain 398079 enhanced the binding of the complement regulatory molecule, factor H. Rather surprisingly, factor H did not bind to sialylated strain 398078. LOS sialylation conferred the LNT LOS-bearing strain complete (100%) resistance to killing by even 50% nonimmune normal human serum (NHS), whereas sialylation of L1 LOS conferred resistance only to 10% NHS. The ability of gonococcal sialylated LNT to bind factor H confers high-level serum resistance, which is not seen with sialylated L1 LOS. Thus, serum resistance mediated by sialylation of gonococcal L1 and LNT LOS occurs by different mechanisms, and specificity of factor H binding to sialylated gonococci is restricted to the LNT LOS species.
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Affiliation(s)
- Sunita Gulati
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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23
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Jordan PW, Snyder LAS, Saunders NJ. Strain-specific differences in Neisseria gonorrhoeae associated with the phase variable gene repertoire. BMC Microbiol 2005; 5:21. [PMID: 15857514 PMCID: PMC1097732 DOI: 10.1186/1471-2180-5-21] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2005] [Accepted: 04/27/2005] [Indexed: 12/02/2022] Open
Abstract
Background There are several differences associated with the behaviour of the four main experimental Neisseria gonorrhoeae strains, FA1090, FA19, MS11, and F62. Although there is data concerning the gene complements of these strains, the reasons for the behavioural differences are currently unknown. Phase variation is a mechanism that occurs commonly within the Neisseria spp. and leads to switching of genes ON and OFF. This mechanism may provide a means for strains to express different combinations of genes, and differences in the strain-specific repertoire of phase variable genes may underlie the strain differences. Results By genome comparison of the four publicly available neisserial genomes a revised list of 64 genes was created that have the potential to be phase variable in N. gonorrhoeae, excluding the opa and pilC genes. Amplification and sequencing of the repeat-containing regions of these genes allowed determination of the presence of the potentially unstable repeats and the ON/OFF expression state of these genes. 35 of the 64 genes show differences in the composition or length of the repeats, of which 28 are likely to be associated with phase variation. Two genes were expressed differentially between strains causing disseminated infection and uncomplicated gonorrhoea. Further study of one of these in a range of clinical isolates showed this association to be due to sample size and is not maintained in a larger sample. Conclusion The results provide us with more evidence as to which genes identified through comparative genomics are indeed phase variable. The study indicates that there are large differences between these four N. gonorrhoeae strains in terms of gene expression during in vitro growth. It does not, however, identify any clear patterns by which previously reported behavioural differences can be correlated with the phase variable gene repertoire.
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Affiliation(s)
- Philip W Jordan
- Bacterial Pathogenesis and Functional Genomics Group, The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Lori AS Snyder
- Bacterial Pathogenesis and Functional Genomics Group, The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Nigel J Saunders
- Bacterial Pathogenesis and Functional Genomics Group, The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
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Leduc I, Richards P, Davis C, Schilling B, Elkins C. A novel lectin, DltA, is required for expression of a full serum resistance phenotype in Haemophilus ducreyi. Infect Immun 2004; 72:3418-28. [PMID: 15155648 PMCID: PMC415671 DOI: 10.1128/iai.72.6.3418-3428.2004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Haemophilus ducreyi, the causative agent of chancroid, is highly resistant to the complement-mediated bactericidal activity of normal human serum (NHS). Previously, we identified DsrA (for ducreyi serum resistance A), a major factor required for expression of the serum resistance phenotype in H. ducreyi. We describe here a second outer membrane protein, DltA (for ducreyi lectin A), which also contributes to serum resistance in H. ducreyi. Isogenic dltA mutants, constructed in 35000HP wild-type and FX517 dsrA backgrounds, were more susceptible to the bactericidal effects of NHS than each respective parent, demonstrating the additive effect of the mutations. Furthermore, expression of dltA in H. influenzae strain Rd rendered this highly susceptible strain partially resistant to 5% NHS compared to a vector-control strain. Although primary basic local alignment search tool analysis of the dltA open reading frame revealed no close bacterial homologue, similarity to the beta-chain of the eukaryotic lectin ricin was noted. DltA shares highly conserved structural motifs with the ricin beta chain, such as cysteines and lectin-binding domains. To determine whether dltA was a lectin, ligand blots and affinity chromatography experiments were performed. DltA was affinity purified on immobilized lactose and N-acetylgalactosamine, and N-glycosylated but not glycosidase-treated model glycoproteins bound DltA. These data indicate that DltA is a lectin with specificity for lactose-related carbohydrates (CHO) and is important for H. ducreyi serum resistance.
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Affiliation(s)
- Isabelle Leduc
- Department of Medicine, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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25
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Salaün L, Snyder LA, Saunders NJ. Adaptation by phase variation in pathogenic bacteria. ADVANCES IN APPLIED MICROBIOLOGY 2003; 52:263-301. [PMID: 12964248 DOI: 10.1016/s0065-2164(03)01011-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Laurence Salaün
- Bacterial Pathogenesis and Functional Genomics Group, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
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26
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El Ahmer OR, Braun JM, Amyes SGB, Weir DM, Beuth J, Blackwell CC. Comparison of Moraxella catarrhalis isolates from children and adults for growth on modified New York City medium and potential virulence factors. J Med Microbiol 2003; 52:853-859. [PMID: 12972578 DOI: 10.1099/jmm.0.05124-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Initial studies found that Moraxella catarrhalis isolates from adults that grew on modified New York City medium (MNYC(+)) that contained antibiotics selective for pathogenic neisseriae differed from strains that did not grow on this medium (MNYC(-)) in their potential virulence properties. It was predicted that higher usage of antibiotics to treat respiratory illness in children might result in higher proportions of MNYC(+) isolates if antibiotics were an important selective pressure for this phenotype. Two of 100 adult isolates (2 %) were MNYC(+), compared to 88 of 88 isolates (100 %) from children (P = 0.000). MNYC(+) strains were serum-resistant and bound in higher numbers to HEp-2 cells that were infected with respiratory syncytial virus (RSV). Endotoxin from an MNYC(+) isolate induced significantly higher pro-inflammatory response levels than endotoxin from an MNYC(-) strain. MNYC(-) adult isolates expressed haemagglutinins and bound in lower numbers to RSV-infected cells, but serum resistance was variable. All isolates from children were MNYC(+), serum-resistant and bound in greater numbers to RSV-infected cells. These results indicate that both RSV infection and antibiotic usage select for the MNYC(+) phenotype.
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Affiliation(s)
- Omar R El Ahmer
- Department of Medical Microbiology, University of Edinburgh, Edinburgh, Scotland, UK 2Institute for Scientific Evaluation of Naturopathy, University of Cologne, Cologne, Germany 3Discipline of Immunology and Microbiology, University of Newcastle, Newcastle, Australia
| | - J Matthias Braun
- Department of Medical Microbiology, University of Edinburgh, Edinburgh, Scotland, UK 2Institute for Scientific Evaluation of Naturopathy, University of Cologne, Cologne, Germany 3Discipline of Immunology and Microbiology, University of Newcastle, Newcastle, Australia
| | - Sebastian G B Amyes
- Department of Medical Microbiology, University of Edinburgh, Edinburgh, Scotland, UK 2Institute for Scientific Evaluation of Naturopathy, University of Cologne, Cologne, Germany 3Discipline of Immunology and Microbiology, University of Newcastle, Newcastle, Australia
| | - Donald M Weir
- Department of Medical Microbiology, University of Edinburgh, Edinburgh, Scotland, UK 2Institute for Scientific Evaluation of Naturopathy, University of Cologne, Cologne, Germany 3Discipline of Immunology and Microbiology, University of Newcastle, Newcastle, Australia
| | - Josef Beuth
- Department of Medical Microbiology, University of Edinburgh, Edinburgh, Scotland, UK 2Institute for Scientific Evaluation of Naturopathy, University of Cologne, Cologne, Germany 3Discipline of Immunology and Microbiology, University of Newcastle, Newcastle, Australia
| | - C Caroline Blackwell
- Department of Medical Microbiology, University of Edinburgh, Edinburgh, Scotland, UK 2Institute for Scientific Evaluation of Naturopathy, University of Cologne, Cologne, Germany 3Discipline of Immunology and Microbiology, University of Newcastle, Newcastle, Australia
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Abstract
Bordetella pertussis must survive the defenses of the human respiratory tract including the complement system. The BrkA (Bordetella resistance to killing) protein prevents killing by the antibody-dependent classical pathway. In this study, the ability of B. pertussis to activate the human complement cascade by other pathways was examined. B. pertussis was not killed in serum depleted of C2, however serum depleted for factor B killed B. pertussis as efficiently as intact serum, suggesting complement activation occurred exclusively by the classical pathway. B. pertussis was not killed by serum depleted of antibody, suggesting the bacteria fail to activate the antibody-independent branches of the classical pathway, including the mannose binding lectin pathway. Mutants lacking the terminal trisaccharide of lipopolysaccharide retained the complement-resistant phenotype, suggesting this structure does not influence activation of complement.
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Affiliation(s)
- Michael G Barnes
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, 231 Sabin Way, ML 0524, Cincinnati, OH 45267, USA
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Inzana TJ, Glindemann G, Cox AD, Wakarchuk W, Howard MD. Incorporation of N-acetylneuraminic acid into Haemophilus somnus lipooligosaccharide (LOS): enhancement of resistance to serum and reduction of LOS antibody binding. Infect Immun 2002; 70:4870-9. [PMID: 12183531 PMCID: PMC128230 DOI: 10.1128/iai.70.9.4870-4879.2002] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Haemophilus somnus isolates from cases of thrombotic meningoencephalitis, pneumonia, and other disease sites are capable of undergoing a high rate of phase variation in the oligosaccharide component of their lipooligosaccharides (LOS). In contrast, the LOS of commensal strains isolated from the normal reproductive tract phase vary little or not at all. In addition, the LOS of H. somnus shares conserved epitopes with LOS from Neisseria gonorrhoeae, Haemophilus influenzae, and other species that can incorporate sialic acid into their LOS. We now report that growth of disease isolates of H. somnus with CMP-N-acetylneuraminic acid (CMP-NeuAc) or NeuAc added to the medium resulted in incorporation of NeuAc into the LOS. However, NeuAc was not incorporated into the LOS of commensal isolates and one disease isolate following growth in medium containing CMP-NeuAc or NeuAc. Sialylated LOS was detected by an increase in the molecular size or an increase in the amount of the largest-molecular-size LOS electrophoretic bands, which disappeared following treatment with neuraminidase. Sialylated LOS could also be detected by reactivity with Limax flavus agglutinin lectin, which is specific for sialylated species, by dot blot assay; this reactivity was also reversed by neuraminidase treatment. H. somnus strain 2336 LOS was found to contain some sialic acid when grown in medium lacking CMP-NeuAc or NeuAc, although supplementation enhanced NeuAc incorporation. In contrast strain 738, an LOS phase variant of strain 2336, was less extensively sialylated when the growth medium was supplemented with CMP-NeuAc or NeuAc, as determined by electrophoretic profiles and electrospray mass spectrometry. The sialyltransferase of H. somnus strain 738 was confirmed to preferentially sialylate the Gal(beta)-(1-3)-GlcNAc component of the lacto-N-tetraose structure by capillary electrophoresis assay. Enhanced sialylation of the strain 2336 LOS inhibited the binding of monoclonal antibodies to LOS by enzyme immunoassay and Western blotting. Furthermore, sialylation of the LOS enhanced the resistance of H. somnus to the bactericidal action of antiserum to LOS. Sialylation and increased resistance to killing by normal serum also occurred in a deletion mutant that was deficient in the terminal Gal-GlcNAc disaccharide. LOS sialylation may therefore be an important virulence mechanism to protect H. somnus against the host immune system.
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Affiliation(s)
- Thomas J Inzana
- Center for Molecular Medicine and Infectious Diseases, Virginia Polytechnic Institute & State University, Blacksburg, Virginia 24061-0342, USA.
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Tsai CM, Kao G, Zhu P. Influence of the length of the lipooligosaccharide alpha chain on its sialylation in Neisseria meningitidis. Infect Immun 2002; 70:407-11. [PMID: 11748209 PMCID: PMC127647 DOI: 10.1128/iai.70.1.407-411.2002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The sialylation of lipooligosaccharide (LOS) in Neisseria meningitidis plays a role in the resistance of the organism to killing by normal human serum. The length of the alpha chain extending out from the heptose I [Hep (I)] moiety of LOS influenced sialylation of N. meningitidis LOS in vitro and in vivo. The alpha chain required a terminal Gal and a trisaccharide or longer oligosaccharide to serve as an acceptor for sialylation. The disaccharide lactose (Galbeta1-4Glc) in the alpha chain of immunotype L8 LOS could not function as an acceptor for the sialyltransferase, probably due to steric hindrance imposed by the neighboring Hep (II) with phosphorylethanolamine and another group attached.
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Affiliation(s)
- Chao-Ming Tsai
- Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics, Food and Drug Administration, Bethesda, Maryland 20892, USA.
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Abstract
Neisserial lipooligosaccharide (LOS) contains three oligosaccharide chains, termed the alpha, beta, and gamma chains. We used Southern hybridization experiments on DNA isolated from various Neisseria spp. to determine if strains considered to be nonpathogenic possessed DNA sequences homologous with genes involved in the biosynthesis of these oligosaccharide chains. The presence or absence of specific genes was compared to the LOS profiles expressed by each strain, as characterized by their mobilities on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gel and their reactivities with various LOS-specific monoclonal antibodies. A great deal of heterogeneity was seen with respect to the presence of genes encoding glycosyltransferases in Neisseria. All pathogenic species were found to possess DNA sequences homologous with the lgt gene cluster, a group of genes needed for the synthesis of the alpha chain. Some of these genes were also found to be present in strains considered to be nonpathogenic, such as Neisseria lactamica, N. subflava, and N. sicca. Some nonpathogenic Neisseria spp. were able to express high-molecular-mass LOS structures, even though they lacked the DNA sequences homologous with rfaF, a gene whose product must act before gonococcal and meningococcal LOS can be elongated. Using a PCR amplification strategy, in combination with DNA sequencing, we demonstrated that N. subflava 44 possessed lgtA, lgtB, and lgtE genes. The predicted amino acid sequence encoded by each of these genes suggested that they encoded functional proteins; however, structural analysis of LOS isolated from this strain indicated that the bulk of its LOS was not modified by these gene products. This suggests the existence of an additional regulatory mechanism that is responsible for the limited expression of these genes in this strain.
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Affiliation(s)
- D Arking
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742, USA
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31
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Williams BJ, Morlin G, Valentine N, Smith AL. Serum resistance in an invasive, nontypeable Haemophilus influenzae strain. Infect Immun 2001; 69:695-705. [PMID: 11159957 PMCID: PMC97941 DOI: 10.1128/iai.69.2.695-705.2001] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A common feature of many different organisms causing bacteremia is the ability to avoid the bactericidal effects of normal human serum. In Haemophilus influenzae encapsulated strains are particularly serum resistant; however, we found that a nonencapsulated strain (R2866) isolated from the blood of an immunocompetent child with meningitis who had been successfully immunized with H. influenzae type b conjugate vaccine was serum resistant. Since serum resistance usually involves circumventing the action of the complement system, we defined the deposition of various complement components on the surfaces of this H. influenzae strain (R2866), a nonencapsulated avirulent laboratory strain (Rd), and a virulent type b encapsulated strain (Eagan). Membrane attack complex (MAC) accumulation correlated with the loss of bacterial viability; correspondingly, the rates of MAC deposition on the serum-sensitive strain Rd and the serum-resistant strains differed. Analysis of cell-associated immunoglobulin G (IgG), C1q, C3b, and C5b indicated that serum-resistant H. influenzae prevents MAC accumulation by delaying the synthesis of C3b through the classical pathway. Among the initiators of the classical pathway, IgG deposition contributes most of the C3 convertase activity necessary to start the cascade ending with MAC deposition. Despite similar IgG binding, strain R2866 delays C3 convertase activity compared to strain Rd. We conclude that strain R2866 can persist in the bloodstream, in part by inhibiting or delaying C3 deposition on the cell surface, escaping complement mediated killing.
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Affiliation(s)
- B J Williams
- Department of Molecular Microbiology and Immunology, University of Missouri-Columbia, Columbia, Missouri 65212, USA
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32
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Tsai CM. Molecular Mimicry of Host Structures by Lipooligosaccharides of Neisseria Meningitidis: Characterization of Sialylated and Nonsialylated Lacto-N-Neotetraose (Galß1-4GlcNAcß1-3Galβ1-4Glc) Structures in Lipooligosaccharides Using Monoclonal Antibodies and Specific Lectins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2001; 491:525-42. [PMID: 14533820 DOI: 10.1007/978-1-4615-1267-7_35] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Neisseria meningitidis lipooligosaccharides (LOSs) are classified into 12 immunotypes. Most LOSs are heterogeneous in having a few components by SDS-PAGE analysis that differ antigenically and chemically. We have utilized a monoclonal antibody that recognizes lacto-N-neotetraose (LNnT) and the lectin, Maackia amurensis leukoagglutinin (MAL), which is specific for NeuNAcalpha2-3Galbeta1-4GlcNAc trisacchride sequence to characterize the 12 N. meningitidis LOSs. Using the combination of ELISA, SDS-PAGE, Western blotting, and other chemical analyses, we have shown that the LNnT (Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc) sequence was present in the 4.0-kDa LOS components of seven immunotype LOSs seen on SDS-PAGE. Six of the seven LNnT-containing LOSs also bound the MAL lectin indicating that N-acetylneuraminic acid (NeuNAc) was alpha2,3-linked to the LNnT sequence in the LOSs. Sialylation of the terminal Gal of LNnT-containing 4.0-kDa component caused only a slight increase in its apparent MW to 4100 on SDS-PAGE. The one LOS with the LNnT-containing component, but not MAL-binding, was from a Group A N. meningitidis, which does not synthesize CMP-NeuNAc, the substrate needed for LOS sialylation. Thus, it is concluded (1) a common LNnT sequence is present in seven immunotype LOSs in addition to their immunotype epitopes, and (2) NeuNAc is alpha2 --> 3 linked to the terminal Gal of LNnT if a organism synthesizes CMP-NeuNAc such as Groups B and C organisms. The above conclusions are consistent with the published structures of N. meningitidis LOSs. The results also demonstrate that specific carbohydrate-binding lectins and monoclonal antibodies can be used as simple yet effective tools to characterize specific carbohydrate sequences in a bacterial LOS or LPS such as N. meningitidis LOS. It is intriguing that N. meningitidis LOSs mimic certain glycosphingolipids, such as paragloboside (LNnT-ceramide) and sialylparagloboside, and some glycoproteins of the host in having LNnT and N-acetyllactosamine sequences respectively with or without alpha2 --> 3 linked NeuNAc. Epidemiological studies of N. meningitidis suggest that the molecular mimicry of host structures by its LOS plays a role in the pathogenesis of N. meningitidis by helping the organism to evade host immune defenses in man. The molecular mimicry of host structures by LOS or LPS is also found in other human pathogens such as N. gonorrhoeae, Haemophilus ducreyi, H. influenaze, Moraxella catarrhalis, Campylobacter jejuni, and Helicobacter pylori.
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Affiliation(s)
- C M Tsai
- Division of Bacterial Products, Center for Biologics Evaluation and Research, FDA, Bethesda, MD 20892, USA
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Cardinale JA, Clark VL. Expression of AniA, the major anaerobically induced outer membrane protein of Neisseria gonorrhoeae, provides protection against killing by normal human sera. Infect Immun 2000; 68:4368-9. [PMID: 10858263 PMCID: PMC101774 DOI: 10.1128/iai.68.7.4368-4369.2000] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Anaerobically grown Neisseria gonorrhoeae has previously been shown to have elevated serum resistance in the absence of exogenous CMP-N-acetylneuraminic acid or detectable sialylation. We hypothesized that the anaerobically induced gonococcal outer membrane protein AniA might have a role in this phenomenon, as it is the only known gonococcal protein that is absent under aerobic conditions. An N. gonorrhoeae F62 derivative, RUG7035, in which aniA is under control of the tac promoter, was used to examine the effect of AniA expression on serum resistance. In this study, we found that expression of AniA enhanced the serum resistance of N. gonorrhoeae and may account for these earlier observations.
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Affiliation(s)
- J A Cardinale
- Department of Microbiology and Immunology, University of Rochester, Rochester, New York 14642, USA
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34
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Abstract
Pathogenic Neisseria use a variety of mechanisms to survive the bactericidal action of the complement system. Serum resistance is a crucial virulence factor for the development of severe meningococcal disease, meningococcal meningitis and disseminated gonococcal infection. Furthermore, local inflammation at the site of gonococcal infection exposes the bacteria to moderate concentrations of complement factors. We review current concepts of neisserial serum resistance with emphasis on porins and polysaccharides exposed on the neisserial surface and their interaction with components of normal human serum.
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Affiliation(s)
- U Vogel
- Institut für Hygiene und Mikrobiologie, University of Würzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany.
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35
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Vogel U, Claus H, Heinze G, Frosch M. Role of lipopolysaccharide sialylation in serum resistance of serogroup B and C meningococcal disease isolates. Infect Immun 1999; 67:954-7. [PMID: 9916114 PMCID: PMC96410 DOI: 10.1128/iai.67.2.954-957.1999] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
alpha-2,3-Sialyltransferase mutants of three genetically and phenotypically diverse Neisseria meningitidis strains were compared with regard to resistance to human serum and systemic spread in the infant rat. Lipopolysaccharide sialylation was found to be of minor importance for the resistance of serogroup B and C meningococcal disease isolates to complement attack.
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Affiliation(s)
- U Vogel
- Institut für Hygiene und Mikrobiologie, Universität Würzburg, 97080 Würzburg, Germany.
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36
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Tsai CM, Chen WH, Balakonis PA. Characterization of terminal NeuNAcalpha2-3Galbeta1-4GlcNAc sequence in lipooligosaccharides of Neisseria meningitidis. Glycobiology 1998; 8:359-65. [PMID: 9499383 DOI: 10.1093/glycob/8.4.359] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Group B and C Neisseria meningitidis are the major cause of meningococcal disease in the United States and in Europe. N . meningitidis lipooligosaccharide (LOS), a major surface antigen, can be divided into 12 immunotypes of which L1 through L8 were found among Group B and C organisms. Groups B and C but not Group A may sialylate their LOSs with N-acetylneuraminic acid (NeuNAc) at the nonreducing end because they synthesize CMP-NeuNAc. Using sialic acid-galactose binding lectins as probes in an ELISA format, six of the eight LOS immunotypes (L2, L3, L4, L5, L7, and L8) in Groups B and C bound specifically to Maackia amurensis leukoagglutinin (MAL), which recognizes NeuNAcalpha2-3Galbeta1-4GlcNAc/Glc sequence, but not to Sambucus nigra agglutinin, which binds NeuNAcalpha2-6Gal sequence. The combination of SDS-PAGE and MAL-blot analyses revealed that these six LOSs contained only the NeuNAcalpha2-3Galbeta1-4GlcNAc trisaccharide sequence in their 4.1 kDa LOS components, which have a common terminal lacto-N-neotetraose (LNnT, Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc) structure when nonsialylated as shown by previous studies. The LOS-lectin binding was abolished when the LOSs were treated with Newcastle disease viral neuraminidase which cleaves alpha2-->3 linked sialic acid. Methylation analysis of a representative LOS (L2) confirmed that NeuNAc is 2-->3 linked to Gal. Thus, these LOSs structurally mimic certain glycolipids, i.e., paragloboside (LNnT-ceramide) and sialylparagloboside and some glycoproteins in having LNnT and N-acetyllactosamine sequences, respectively, with or without alpha2-->3 linked NeuNAc. The molecular mimicry of the LOSs may play a role in the pathogenesis of N.meningitidis by assisting the organism to evade host immune defenses in man.
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Affiliation(s)
- C M Tsai
- Division of Bacterial Products, Center for Biologics Evaluation and Research, FDA, Bethesda, MD 20892, USA
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37
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Estabrook MM, Griffiss JM, Jarvis GA. Sialylation of Neisseria meningitidis lipooligosaccharide inhibits serum bactericidal activity by masking lacto-N-neotetraose. Infect Immun 1997; 65:4436-44. [PMID: 9353017 PMCID: PMC175638 DOI: 10.1128/iai.65.11.4436-4444.1997] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Exogenous sialylation of gonococcal lipooligosaccharide causes resistance to serum bactericidal activity. The aim of this study was to determine how lipooligosaccharide sialylation affects the serum sensitivities of group C Neisseria meningitidis strains. The relationship between the degree of sialylation or expression of the lipooligosaccharide sialic acid acceptor, lacto-N-neotetraose (LNnT), of nine meningococcal strains and their sensitivities to a pool of normal human sera was assessed. All strains expressed LNnT that was variously endogenously sialylated. Susceptibility to serum bactericidal activity ranged from extremely sensitive to resistant in 50% serum. For endogenously sialylated strains, the amount of killing correlated with the amount of free LNnT above a threshold of expression; strains that expressed less than the threshold survived in 25% serum. All strains added more sialic acid when they were grown in medium that contained cytidine monophospho-N-acetylneuraminic acid. Exogenous sialylation reduced the expression of free LNnT and significantly increased serum resistance. Exogenous sialylation affected killing through both classical and alternative complement pathways. The killing of exogenously sialylated strains also correlated with the amount of free LNnT. The amounts of endogenous, exogenous, and total sialic acid bound to LNnT did not correlate with the resistance of strains to serum bactericidal activity; rather, the loss of free LNnT expression by sialylation was associated with resistance. In conclusion, the expression of free LNnT by group C meningococcal strains is directly associated with the amount of killing of organisms in pooled human sera. Both endogenous and exogenous lipooligosaccharide sialylation are associated with increased serum resistance by masking LNnT.
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Affiliation(s)
- M M Estabrook
- Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA.
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38
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Vogel U, Weinberger A, Frank R, Müller A, Köhl J, Atkinson JP, Frosch M. Complement factor C3 deposition and serum resistance in isogenic capsule and lipooligosaccharide sialic acid mutants of serogroup B Neisseria meningitidis. Infect Immun 1997; 65:4022-9. [PMID: 9317002 PMCID: PMC175578 DOI: 10.1128/iai.65.10.4022-4029.1997] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Serogroup B meningococci express sialic acids on their surfaces as a modification of the lipooligosaccharide (LOS) and as capsular material consisting of alpha2,8-linked sialic acid homopolymers. The aim of this study was to elucidate the impact of each sialic acid component on the deposition of complement factor C3 and serum resistance. For this purpose, we used isogenic mutants deficient in capsule expression (a polysialyltransferase mutant) or sialylation of the LOS (a galE mutant) or both (a mutant with a deletion of the cps gene locus). Bactericidal assays using 40% normal human serum (NHS) demonstrated that both the capsule and LOS sialic acid are indispensable for serum resistance. By immunoblotting with monoclonal antibody MAb755 that is specific for the C3 alpha-chain, we were able to demonstrate that C3 from 40% NHS was covalently linked to the surface structures of meningococci as C3b and iC3b, irrespective of the surface sialic acid compounds. However, C3b linkage was more pronounced and occurred on a larger number of target molecules in galE mutants with nonsialylated LOS than in meningococci with wild-type LOS, irrespective of the capsule phenotype. C3b deposition was caused by both the classical pathway (CP) and the alternative pathway of complement activation. Use of 10% NHS revealed that at low serum concentrations, C3 deposition occurred via the CP and was detected primarily on nonsialylated-LOS galE mutants, irrespective of the capsular phenotype. Accordingly, immunoglobulin M (IgM) binding to meningococci from heat-inactivated NHS was demonstrated only in both encapsulated and unencapsulated galE mutants. In contrast, inhibition of IgA binding required both encapsulation and LOS sialylation. We conclude that serum resistance in wild-type serogroup B meningococci can only be partly explained by an alteration of the C3b linkage pattern, which seems to depend primarily on the presence of wild-type LOS, since a serum-resistant phenotype also requires capsule expression.
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Affiliation(s)
- U Vogel
- Institut für Hygiene und Mikrobiologie, Universität Würzburg, Germany.
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39
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Spence JM, Chen JC, Clark VL. A proposed role for the lutropin receptor in contact-inducible gonococcal invasion of Hec1B cells. Infect Immun 1997; 65:3736-42. [PMID: 9284146 PMCID: PMC175533 DOI: 10.1128/iai.65.9.3736-3742.1997] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We previously reported the existence of a contact-inducible, enhanced invasion phenotype in the obligate human pathogen Neisseria gonorrhoeae. Our present studies showed that the ability of glutaraldehyde-fixed eucaryotic cells to convert gonococci (GC) to this invasive phenotype (Inv+) is limited to cells derived from reproductive tissues. We present evidence that GC recognize the lutropin receptor (LHr), which recognizes both luteinizing hormone and human chorionic gonadotropin (hCG), as the tissue-specific environmental signal that induces the conversion of GC to the Inv+ phenotype. By competitive binding studies, we showed that Inv+ GC bind to Hec1B cells, a human endometrial cell line, by a unique adhesin not present on noninduced GC and that this Inv+ GC-specific binding is completely blocked by the addition of hCG. We demonstrated that limiting the access of GC to LHr decreases the ability of the host cell to both convert GC to the Inv+ phenotype and serve as a target for Inv+ GC invasion. We propose a model of GC invasion of Hec1B cells in which the LHr plays a dual role both as an induction signal and as part of the internalization mechanism. This utilization of LHr could account for both the preponderance of complicated GC disease in women and the observed correlation of the disease with the onset of menses.
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Affiliation(s)
- J M Spence
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, New York 14642, USA
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40
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Bos MP, Hogan D, Belland RJ. Selection of Opa+ Neisseria gonorrhoeae by limited availability of normal human serum. Infect Immun 1997; 65:645-50. [PMID: 9009326 PMCID: PMC176109 DOI: 10.1128/iai.65.2.645-650.1997] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Experimental infections of human male volunteers with Neisseria gonorrhoeae have provided valuable insights into the early stages of gonorrheal disease. Bacterial variants expressing outer membrane opacity (Opa) proteins appear to be selected from the inoculum during a period in which total recoverable numbers of bacteria decrease rapidly. This apparent survival advantage occurs simultaneously with the onset of an inflammatory response, characterized by local production of interleukin 6 (IL-6) and IL-8 and the appearance of leukocytes in urine. Since the inflammatory response may also result in the presence of serum factors on the mucosal surface, we investigated the possibility that killing in normal human serum (NHS) leads to the selection of Opa+ variants. We therefore studied killing of separate populations and mixtures of Opa- and Opa+ N. gonorrhoeae MS11mk in NHS. Expression of an Opa protein conferred a survival advantage upon the organism; i.e., the Opa+ variants were more serum resistant than their isogenic Opa- counterparts, resulting in a selection for Opa+ phenotypes when a mixture of Opa+ and Opa- gonococci (GC) was exposed to submaximal doses of NHS. This selection was observed in three different lipooligosaccharide (LOS) backgrounds, indicating that it was not due to a difference in LOS expression between Opa- and Opa+ phenotypes. Incubation in NHS of sialylated GC resulted in a similar selection for Opa+ variants. The presence of normal human urine during the serum killing assay had no effect on the selection phenomenon but drastically depleted NHS of bactericidal activity, which was found to be at least partly due to complement inhibition. The results suggest that serum killing may contribute to the transition from Opa- to Opa+ phenotypes during the early stages of infection of the male urethra.
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Affiliation(s)
- M P Bos
- Laboratory of Microbial Structure and Function, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840, USA.
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41
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Moran AP, Prendergast MM, Appelmelk BJ. Molecular mimicry of host structures by bacterial lipopolysaccharides and its contribution to disease. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 1996; 16:105-15. [PMID: 8988391 DOI: 10.1111/j.1574-695x.1996.tb00127.x] [Citation(s) in RCA: 205] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The core oligosaccharides of low-molecular-weight lipopolysaccharide (LPS), also termed lipooligosaccharide (LOS), of pathogenic Neisseria spp. mimic the carbohydrate moieties of glycosphingolipids present on human cells. Such mimicry may serve to camouflage the bacterial surface from the host. The LOS component is antigenically and/or chemically identical to lactoneoseries glycosphingolipids and can become sialylated in Neisseria gonorrhoeae when the bacterium is grown in the presence of cytidine 5'-monophospho-N-acetylneuraminic acid, the nucleotide sugar of sialic acid. Strains of Neisseria meningitidis and Haemophilus influenzae also express similarly sialylated LPS. Sialylation of the LOS influences susceptibility to bactericidal antibody, may decrease or prevent phagocytosis, cause down-regulation of complement activation, and decrease adherence to neutrophils and the subsequent oxidative burst response. The core oligosaccharides of LPS of Campylobacter jejuni serotypes which are associated with the development of the neurological disorder, Guillain-Barré syndrome (GBS), exhibit mimicry of gangliosides. Cross-reactive antibodies between C. jejuni LPS and gangliosides are considered to play an important role in GBS pathogenesis. In contrast, the O-chain of a number of Helicobacter pylori strains exhibit mimicry of Lewis(x) and Lewis(y) blood group antigens. The role of this mimicry remains to be investigated, but may play a role in bacterial camouflage, the induction of autoimmunity and immune suppression in H. pylori-associated disease.
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Affiliation(s)
- A P Moran
- Department of Microbiology, University College, Galway, Ireland.
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42
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McGee DJ, Rest RF. Regulation of gonococcal sialyltransferase, lipooligosaccharide, and serum resistance by glucose, pyruvate, and lactate. Infect Immun 1996; 64:4630-7. [PMID: 8890217 PMCID: PMC174423 DOI: 10.1128/iai.64.11.4630-4637.1996] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Strain F62 of Neisseria gonorrhoeae gonococci (GC) is sensitive to normal human serum unless CMP-N-acetylneuraminic acid (CMP-NANA) is present. NANA is transferred primarily to a 4.5-kDa lipooligosaccharide (LOS) structure by a GC sialyltransferase (Stase). We investigated LOS and Stase expression and serum resistance in strain F62 grown in different carbon sources and growth conditions. Pyruvate-grown GC expressed 1.9- to 5.6-fold more Stase activity than did glucose-grown GC, whereas lactate-grown GC generally expressed intermediate Stase activities. Broth-grown GC expressed two- to fourfold more Stase activity than did plate-grown GC in all carbon sources. Pyruvate- or lactate-grown GC expressed significantly more of the sialylateable 4.5-kDa LOS species than did glucose-grown GC. Anaerobically, the 4.5-kDa LOS species was expressed in greater quantity than the 4.9-kDa N-acetyl galactosamine-terminating species in all carbon sources. Pyruvate-grown GC also incorporated up to threefold more radiolabelled CMP-NANA onto the 4.5-kDa LOS species than did glucose-grown GC. In serum resistance studies, pyruvate-grown GC were 6.5- to 16.1-fold more serum resistant than glucose-grown GC at limiting CMP-NANA concentrations (1.56 to 12.50 microg/ml). Taken together, these results indicate that gonococcal expression of Stase activity is up-regulated by growth in pyruvate or lactate, which correlates with enhanced expression of the sialylateable 4.5-kDa LOS and, for growth in pyruvate, correlates with enhanced sialylation of gonococcal LOS and greater serum resistance. In different in vivo niches, gonococcal LOS sialylation, serum resistance, and interaction with host cells can be highly regulated.
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Affiliation(s)
- D J McGee
- Department of Microbiology and Immunology, MCP-Hahnemann School of Medicine, Allegheny University of the Health Sciences, Philadelphia, Pennsylvania 19129, USA
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Pettit RK, Filiatrault MJ, Martin ES. Alteration of gonococcal protein expression in acidic culture. Infect Immun 1996; 64:1039-42. [PMID: 8641756 PMCID: PMC173877 DOI: 10.1128/iai.64.3.1039-1042.1996] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We grew Neisseria gonorrhoeae under acidic, neutral, and alkaline conditions and noted altered expression of at least 12 outer membrane proteins between 31 and 100 kDa in size. One protein whose expression was upregulated under acidic conditions was gonococcal heat shock protein 63. These proteins may contribute to the pathogenesis of gonorrhea in the urogenital tract.
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Affiliation(s)
- R K Pettit
- Department of Biology, Western Oregon State College, Monmouth, 97361, USA
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Yang QL, Gotschlich EC. Variation of gonococcal lipooligosaccharide structure is due to alterations in poly-G tracts in lgt genes encoding glycosyl transferases. J Exp Med 1996; 183:323-7. [PMID: 8551240 PMCID: PMC2192423 DOI: 10.1084/jem.183.1.323] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The lipooligosaccharide (LOS) expressed by gonococci spontaneously varies its structure at high frequency, but the underlying genetic mechanism has not been described. We have previously reported that the genes encoding the glycosyl transferases responsible for the biosynthesis of the variable alpha chain of the LOS of Neisseria gonorrhoeae are located in a locus containing five genes, lgtA, lgtB, lgtC, lgtD, and lgtE. Sequence analysis showed that lgtA, lgtC, and lgtD contained poly-G tracts within the coding frames, leading to the hypothesis that shifts in the number of guanosine residues in the poly-G tracts might be responsible for the high frequency variation in structure of gonococcal LOS. We now provide experimental evidence confirming this hypothesis.
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Affiliation(s)
- Q L Yang
- Laboratory of Bacterial Pathogenesis and Immunology, Rockefeller University, New York 10021-6399, USA
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45
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Ullrich J, van Putten JP. Identification of the gonococcal glmU gene encoding the enzyme N-acetylglucosamine 1-phosphate uridyltransferase involved in the synthesis of UDP-GlcNAc. J Bacteriol 1995; 177:6902-9. [PMID: 7592484 PMCID: PMC177559 DOI: 10.1128/jb.177.23.6902-6909.1995] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
In searching for the gonococcal sialyltransferase gene(s), we cloned a 3.8-kb DNA fragment from gonococcus strain MS11 that hybridized with the oligonucleotide JU07, which was derived from the conserved C terminus of the sialyl motif present in mammalian sialyltransferases. Sequencing of the fragment revealed four putative open reading frames (ORFs), one of which (ORF-1) contained a partial sialyl motif including the amino acid sequence VGSKT, which is highly conserved among sialyltransferases. The gene was flanked by two inverted repeats containing the neisserial DNA uptake sequence and was preceded by a putative sigma 54 promoter. Database searches, however, revealed a high degree of homology between ORF-1 and the N-acetylglucosamine 1-phosphate uridyltransferase (GlmU) of Escherichia coli and Bacillus subtilis and not with any known sialyltransferase. This homology was further established by the successful complementation of an orf-1 mutation by the E. coli glmU gene. Enzyme assays demonstrated that ORF-1 did not possess sialyltransferase activity but mimicked GlmU function catalyzing the conversion of N-acetylglucosamine 1-phosphate into UDP-N-acetylglucosamine, which is a key metabolite in the syntheses of lipopolysaccharide, peptidoglycan, and sialic acids.
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Affiliation(s)
- J Ullrich
- Max-Planck-Institut für Biologie, Abteilung Infektionsbiologie, Tübingen, Germany
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46
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Pettit RK, Martin ES, Wagner SM, Bertolino VJ. Phenotypic modulation of gonococcal lipooligosaccharide in acidic and alkaline culture. Infect Immun 1995; 63:2773-5. [PMID: 7790098 PMCID: PMC173372 DOI: 10.1128/iai.63.7.2773-2775.1995] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Neisseria gonorrhoeae infects a diverse array of niches in its human host, which expose the organism to dramatic variations in pH. We examined growth and lipooligosaccharide expression of two gonococcal strains in liquid and solid cultures under acidic, neutral, and alkaline conditions. Growth rates in broth were similar under the three conditions, and the pH remained fairly constant throughout the growth cycle. Altered lipooligosaccharide expression at the different pHs was noted in both plate- and broth-grown organisms.
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Affiliation(s)
- R K Pettit
- Department of Biology, State University of New York College at Potsdam 13676, USA
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47
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van Putten JP, Robertson BD. Molecular mechanisms and implications for infection of lipopolysaccharide variation in Neisseria. Mol Microbiol 1995; 16:847-53. [PMID: 7476183 DOI: 10.1111/j.1365-2958.1995.tb02312.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The lipopolysaccharides of the pathogenic Neisseria species are subject to structural variation owing to a combination of intrinsic changes in lipopolysaccharide (LPS) biosynthesis and external modification of the LPS molecule with sialic acid. This variation appears to control bacterial behaviour by altering their ability to interact with human cells and to evade host immune defences. This interconversion of LPS phenotypes, which is also observed during the natural infection, is probably due to environmental regulation of LPS biosynthesis superimposed on spontaneous changes in the DNA of distinct LPS loci. LPS variation may be a common strategy of mucosal pathogens to colonize and persist within the human host.
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Affiliation(s)
- J P van Putten
- Max-Planck-Institut fuer Biologie, Infektionsbiologie, Tuebingen, Germany
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48
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Abstract
Immunity to neisserial infection involves complex interactions between antibody, complement and bacterial cell-surface molecules. Neisseria species express polysaccharide and glycolipid membrane components, which downregulate complement activation. The pathogenic potential of Neisseria depends on evasion of the complement cascade.
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Affiliation(s)
- G A Jarvis
- Dept of Laboratory Medicine, University of California, San Francisco 94121, USA
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Chen T, Swanson J, Wilson J, Belland RJ. Heparin protects Opa+ Neisseria gonorrhoeae from the bactericidal action of normal human serum. Infect Immun 1995; 63:1790-5. [PMID: 7729887 PMCID: PMC173225 DOI: 10.1128/iai.63.5.1790-1795.1995] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The pathobiological significance of lipooligosaccharide (LOS) and outer membrane opacity protein (Opa) changes in gonorrheal disease are poorly understood. We assessed variants of strain MS11mk with different LOS and Opa phenotypes for their liability to killing by normal human sera. LOS differences correlated with strikingly disparate susceptibilities to serum killing; LOSa variants were serum resistant, LOSb variants were serum sensitive, and sialylation of LOSb variants enhanced their survival (as reported previously). Opa phenotype had little influence on the killing of serum-sensitive LOSb cells that were incubated directly in normal human sera, but preincubation of Opa+ LOSb variants in heparin increased their serum resistance whereas Opa- LOSb variants showed no change. Some Opa proteins conferred slightly higher resistance than others, but heparin preincubation increased serum resistance for variants expressing each of seven Opa proteins. These in vitro phenomena may relate to conditions within the male urethra where sulfate-containing proteoglycans are abundant and where antibody and complement may transude from blood plasma. The results suggest that the selective advantage for Opa+ Neisseria gonorrhoeae bacteria observed in vivo may reflect their ability to utilize host cell components to resist killing by host defenses.
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Affiliation(s)
- T Chen
- Laboratory of Microbial Structure and Function, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840, USA
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Blake MS, Blake CM, Apicella MA, Mandrell RE. Gonococcal opacity: lectin-like interactions between Opa proteins and lipooligosaccharide. Infect Immun 1995; 63:1434-9. [PMID: 7890406 PMCID: PMC173171 DOI: 10.1128/iai.63.4.1434-1439.1995] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Previous evidence from our laboratory suggested that the tight intercellular adhesions between the outer membranes of gonococci displaying the opacity colony phenotype occurred because Opa proteins expressed on one gonococcus adhered to the lipooligosaccharide (LOS) of the opposing bacterium (M.S. Blake, p. 51-66, in G. G. Jackson and H. Thomas, ed., The Pathogenesis of Bacterial Infections, 1985, and M. S. Blake and E. C. Gotschlich, p. 377-400, in M. Inouye, ed., Bacterial Outer Membranes as Model Systems, 1986). A noncompetitive inhibition assay used previously to determine the carbohydrate structures recognized by the major hepatic asialoglycoprotein receptor was modified to determine the gonococcal LOS structures that bind Opa proteins (R. T. Lee, Targeted Diagn. Ther. Ser. 4:65-84, 1991). The LOS carbohydrates used in these assays were LOS structures purified from pyocin LOS mutants of Neisseria gonorrhoeae 1291 described by K. C. Dudas and M. A. Apicella (Infect. Immun. 56:499-504, 1988) and further characterized by C. M. John et al. (J. Biol. Chem. 266:19303-19311, 1991). Purified gonococcal Opa proteins were incubated with each of the parent and mutant LOS, and the amount of binding of Opa proteins was measured by a direct enzyme-linked immunosorbent assay using the Opa-specific monoclonal antibody 4B12. The affinities of the Opa proteins for each of the LOS were determined indirectly by measuring the concentrations of Opa proteins that noncompetitively inhibited 50% of the binding of LOS-specific monoclonal antibodies. This concentration is inversely proportional to the affinity of the inhibitor (R. T. Lee, Targeted Diagn. Ther. Ser. 4:65-84, 1991). Our data suggest that the gonococcal Opa proteins tested had the highest affinity for the Gal beta 1-4GlcNAc residue present on the gonococcal lactoneoseries LOS. This affinity was comparable to that reported for the binding of the major hepatic asialoglycoprotein receptor to glycoconjugates containing terminal galactose and N-acetylgalactosamine (R. T. Lee, Targeted Diagn. Ther. Ser. 4:65-84, 1991). After sialylation of the lactoneoseries LOS, presumably on the terminal galactose residue, the interaction with the Opa proteins was ablated. Therefore, the gonococcal Opa-LOS and mammalian epithelial cell asialoglycoprotein receptor-carbohydrate interactions have quite similar specificities.
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Affiliation(s)
- M S Blake
- Laboratory of Bacteriology and Immunology, Rockefeller University, New York, New York 10021
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