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Nawa M, Mwansa J, Mwaba J, Kaonga P, Mukubesa AN, Simuyandi M, Chisenga CC, Alabi P, Mwananyanda L, Thea DM, Chilengi R, Kwenda G. Microbiologic and virulence characteristics of Moraxella catarrhalis isolates from Zambian children presenting with acute pneumonia. Pediatr Pulmonol 2022; 57:3084-3093. [PMID: 36056795 DOI: 10.1002/ppul.26138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 07/18/2022] [Accepted: 08/27/2022] [Indexed: 01/11/2023]
Abstract
BACKGROUND Moraxella catarrhalis is one of the bacterial pathogens associated with childhood pneumonia, but its clinical importance is not clearly defined. OBJECTIVE This study aimed to investigate the microbiologic and virulence characteristics of M. catarrhalis isolates obtained from children with pneumonia in Lusaka, Zambia. METHODS This retrospective, cross-sectional study analyzed 91 M. catarrhalis isolates from induced sputum samples of children less than 5 years of age with pneumonia enrolled in the Pneumonia Etiology Research for Child Health study in Lusaka, Zambia between 2011 and 2014. Bacteria identification and virulence genes detection were performed by PCR and DNA sequencing, while antimicrobial susceptibility testing was determined by the Kirby-Bauer method. RESULTS All the M. catarrhalis isolates were obtained from good-quality sputum samples and were the predominant bacteria. These isolates harbored virulence genes copB (100%), ompE (69.2%), ompCD (71.4%), uspA1 (92.3%), and uspA2 (69.2%) and were all β-lactamase producers. They showed resistance to ampicillin (100%), amoxicillin (100%), trimethoprim-sulfamethoxazole (92.3%), ciprofloxacin (46.2%), chloramphenicol (45.1%), erythromycin (36.3%), tetracycline (25.3%), cefuroxime (11.0%), and amoxicillin-clavulanate (2.2%), with 71.4% displaying multi-drug resistant phenotype but all susceptible to imipenem (100%). CONCLUSION This study showed that M. catarrhalis isolates were the predominant or only bacterial isolates from the sputum samples analyzed. The findings provide supportive evidence for the pathogenic potential role of this bacterium in pediatric pneumonia. High multidrug resistance was also observed amongst the isolates, which can result in affected patients not responding to standard treatment, leading to prolonged illness, increased healthcare costs, and risk of death.
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Affiliation(s)
- Mukena Nawa
- Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.,Department of Biomedical Sciences, School of Health Sciences, University of Zambia, Lusaka, Zambia
| | - James Mwansa
- Department of Postgraduate Studies and Research, School of Medicine, Lusaka Apex Medical University, Lusaka, Zambia
| | - John Mwaba
- Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.,Department of Biomedical Sciences, School of Health Sciences, University of Zambia, Lusaka, Zambia
| | - Patrick Kaonga
- Department of Internal Medicine, School of Medicine, University of Zambia, Lusaka, Zambia
| | - Andrew N Mukubesa
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | | | | | - Peter Alabi
- Centre for Infectious Disease Research in Zambia, Lusaka, Zambia
| | - Lawrence Mwananyanda
- Department of Global Health, Boston University School of Public Health, Boston, Massachusetts, USA
| | - Donald M Thea
- Department of Global Health, Boston University School of Public Health, Boston, Massachusetts, USA
| | - Roma Chilengi
- Centre for Infectious Disease Research in Zambia, Lusaka, Zambia
| | - Geoffrey Kwenda
- Department of Biomedical Sciences, School of Health Sciences, University of Zambia, Lusaka, Zambia
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FHUSPA2/10 is a bactericidal monoclonal antibody targeting multiple repeated sequences of Moraxella catarrhalis UspA2. Vaccine 2022; 40:6520-6527. [PMID: 36202640 DOI: 10.1016/j.vaccine.2022.09.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/13/2022] [Accepted: 09/15/2022] [Indexed: 12/05/2022]
Abstract
Moraxella catarrhalis is an important and common respiratory pathogen that can cause Otitis Media, Community Acquired Pneumonia, and has been associated with an increased risk of exacerbations in chronic obstructive pulmonary disease in adults, leading to morbidity and mortality. Its ubiquitous surface protein A2 (UspA2) has been shown to interact with host structures and extracellular matrix proteins, suggesting a role at an early stage of infection and a contribution to bacterial serum resistance. The UspA proteins are homo-trimeric autotransporters that appear as a lollipop-shaped structure in electron micrographs. They are composed of an N-terminal head with adhesive properties, followed by a stalk, which ends by an amphipathic helix and a C-terminal membrane domain. The three family members UspA1, UspA2 and UspA2H, present different amino acid signatures both at the head and membrane-spanning regions. By combining electron microscopy, hydrogen deuterium exchange mass spectrometry and protein modeling, we identified a shared and repeated epitope recognized by FHUSPA2/10, a potent cross-bactericidal monoclonal antibody raised by UspA2 and deduced key amino acids involved in the binding. The finding strengthens the potential of UspA2 to be incorporated in a vaccine formulation against M. catarrhalis.
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3
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Shhadeh A, Galaski J, Alon-Maimon T, Fahoum J, Wiener R, Slade DJ, Mandelboim O, Bachrach G. CEACAM1 Activation by CbpF-Expressing E. coli. Front Cell Infect Microbiol 2021; 11:699015. [PMID: 34395310 PMCID: PMC8358318 DOI: 10.3389/fcimb.2021.699015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 07/13/2021] [Indexed: 01/04/2023] Open
Abstract
Recent studies on the oral, anaerobic, gram-negative bacterium Fusobacterium nucleatum revealed its presence and involvement in colorectal, esophageal and breast cancer. We previously demonstrated that F. nucleatum binds and activates the human inhibitory receptors TIGIT and CEACAM1 leading to inhibition of T and NK cell anti-tumor immunity. CEACAM1 was found to be bound and activated by the fusobacterial trimeric autotransporter adhesin CbpF. Here we report the generation of a recombinant E. coli expressing full-length CbpF that efficiently binds and activates CEACAM1.
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Affiliation(s)
- Amjad Shhadeh
- The Institute of Dental Sciences, The Hebrew University-Hadassah School of Dental Medicine, Jerusalem, Israel
| | - Johanna Galaski
- The Concern Foundation Laboratories at the Lautenberg Center for General and Tumor Immunology, Department of Immunology and Cancer Research, Institute for Medical Research Israel Canada (IMRIC), Faculty of Medicine, The Hebrew University Medical School, Jerusalem, Israel.,I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tamar Alon-Maimon
- The Institute of Dental Sciences, The Hebrew University-Hadassah School of Dental Medicine, Jerusalem, Israel
| | - Jamal Fahoum
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel Canada (IMRIC), Faculty of Medicine, The Hebrew University Medical School, Jerusalem, Israel
| | - Reuven Wiener
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel Canada (IMRIC), Faculty of Medicine, The Hebrew University Medical School, Jerusalem, Israel
| | - Daniel J Slade
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Ofer Mandelboim
- The Concern Foundation Laboratories at the Lautenberg Center for General and Tumor Immunology, Department of Immunology and Cancer Research, Institute for Medical Research Israel Canada (IMRIC), Faculty of Medicine, The Hebrew University Medical School, Jerusalem, Israel
| | - Gilad Bachrach
- The Institute of Dental Sciences, The Hebrew University-Hadassah School of Dental Medicine, Jerusalem, Israel
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4
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Riesbeck K. Complement evasion by the human respiratory tract pathogens Haemophilus influenzae and Moraxella catarrhalis. FEBS Lett 2020; 594:2586-2597. [PMID: 32053211 DOI: 10.1002/1873-3468.13758] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 01/26/2020] [Accepted: 02/09/2020] [Indexed: 12/14/2022]
Abstract
All infective bacterial species need to conquer the innate immune system in order to colonize and survive in their hosts. The human respiratory pathogens Haemophilus influenzae and Moraxella catarrhalis are no exceptions and have developed sophisticated mechanisms to evade complement-mediated killing. Both bacterial species carry lipooligosaccharides preventing complement attacks and attract and utilize host complement regulators C4b binding protein and factor H to inhibit the classical and alternative pathways of complement activation, respectively. In addition, the regulator of the terminal pathway of complement activation, vitronectin, is hijacked by both bacteria. An array of different outer membrane proteins (OMP) in H. influenzae and M. catarrhalis simultaneously binds complement regulators, but also plasminogen. Several of the bacterial complement-binding proteins are important adhesins and contain highly conserved regions for interactions with the host. Thus, some of the OMP are viable targets for new therapeutics, including vaccines aimed at preventing respiratory tract diseases such as otitis media in children and exacerbations in patients suffering from chronic obstructive pulmonary disease.
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Affiliation(s)
- Kristian Riesbeck
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
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5
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Mikula KM, Kolodziejczyk R, Goldman A. Structure of the UspA1 protein fragment from Moraxella catarrhalis responsible for C3d binding. J Struct Biol 2019; 208:77-85. [PMID: 31400508 PMCID: PMC6839023 DOI: 10.1016/j.jsb.2019.08.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 08/03/2019] [Accepted: 08/05/2019] [Indexed: 01/26/2023]
Abstract
UspA1299–452 is a left-handed coiled-coil structure that follows TAA rules. Structure of UspA1299–452 contains part of the long neck domain and of the stalk. UspA1-C3d binding does not saturate at C3d physiological concentrations. The binding constant as measured by thermophoresis is at least 140 μM. Full-length proteins or other factors are important for UspA1-C3d interactions.
The gram-negative bacterium Moraxella catarrhalis infects humans exclusively, causing various respiratory tract diseases, including acute otitis media in children, septicaemia or meningitis in adults, and pneumonia in the elderly. To do so, M. catarrhalis expresses virulence factors facilitating its entry and survival in the host. Among them are the ubiquitous surface proteins (Usps): A1, A2, and A2H, which all belong to the trimeric autotransporter adhesin family. They bind extracellular matrix molecules and inhibit the classical and alternative pathways of the complement cascade by recruiting complement regulators C3d and C4b binding protein. Here, we report the 2.5 Å resolution X-ray structure of UspA1299–452, which previous work had suggested contained the canonical C3d binding site found in both UspA1 and UspA2. We show that this fragment of the passenger domain contains part of the long neck domain (residues 299–336) and a fragment of the stalk (residues 337–452). The coiled-coil stalk is left-handed, with 7 polar residues from each chain facing the core and coordinating chloride ions or water molecules. Despite the previous reports of tight binding in serum-based assays, we were not able to demonstrate binding between C3d and UspA1299–452 using ELISA or biolayer interferometry, and the two proteins run separately on size-exclusion chromatography. Microscale thermophoresis suggested that the dissociation constant was 140.5 ± 8.4 μM. We therefore suggest that full-length proteins or other additional factors are important in UspA1-C3d interactions. Other molecules on the bacterial surface or present in serum may enhance binding of those two molecules.
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Affiliation(s)
- Kornelia M Mikula
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Robert Kolodziejczyk
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Adrian Goldman
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland; Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, UK.
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6
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Laabei M, Liu G, Ermert D, Lambris JD, Riesbeck K, Blom AM. Short Leucine-Rich Proteoglycans Modulate Complement Activity and Increase Killing of the Respiratory Pathogen Moraxella catarrhalis. THE JOURNAL OF IMMUNOLOGY 2018; 201:2721-2730. [PMID: 30266767 DOI: 10.4049/jimmunol.1800734] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 08/30/2018] [Indexed: 12/21/2022]
Abstract
The respiratory pathogen Moraxella catarrhalis is a human-specific commensal that frequently causes acute otitis media in children and stimulates acute exacerbations in chronic obstructive pulmonary disease patients. The exact molecular mechanisms defining host-pathogen interactions promoting pathogenesis are not clearly understood. Limited knowledge hampers vaccine and immunotherapeutic development required to treat this emerging pathogen. In this study, we reveal in detail a novel antibacterial role displayed by short leucine-rich proteoglycans (SLRPs) in concert with complement. We show that fibromodulin (FMOD), osteoadherin (OSAD), and biglycan (BGN) but not decorin (DCN) enhance serum killing of M. catarrhalis. Our results suggest that M. catarrhalis binding to SLRPs is a conserved feature, as the overwhelming majority of clinical and laboratory strains bound all four SLRPs. Furthermore, we resolve the binding mechanism responsible for this interaction and highlight the role of the ubiquitous surface protein (Usp) A2/A2H in mediating binding to host SLRPs. A conserved immune evasive strategy used by M. catarrhalis and other pathogens is the surface acquisition of host complement inhibitors such as C4b-binding protein (C4BP). We observed that FMOD, OSAD, and BGN competitively inhibit binding of C4BP to the surface of M. catarrhalis, resulting in increased C3b/iC3b deposition, membrane attack complex (MAC) formation, and subsequently decreased bacterial survival. Furthermore, both OSAD and BGN promote enhanced neutrophil killing in vitro, both in a complement-dependent and independent fashion. In summary, our results illustrate that SLRPs, FMOD, OSAD, and BGN portray complement-modulating activity enhancing M. catarrhalis killing, defining a new antibacterial role supplied by SLRPs.
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Affiliation(s)
- Maisem Laabei
- Division of Medical Protein Chemistry, Lund University, 21428 Malmö, Sweden
| | - Guanghui Liu
- Division of Medical Protein Chemistry, Lund University, 21428 Malmö, Sweden
| | - David Ermert
- Division of Medical Protein Chemistry, Lund University, 21428 Malmö, Sweden
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
| | - Kristian Riesbeck
- Division of Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, 21428 Malmö, Sweden
| | - Anna M Blom
- Division of Medical Protein Chemistry, Lund University, 21428 Malmö, Sweden;
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7
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Blakeway LV, Tan A, Peak IRA, Seib KL. Virulence determinants of Moraxella catarrhalis: distribution and considerations for vaccine development. MICROBIOLOGY-SGM 2017; 163:1371-1384. [PMID: 28893369 DOI: 10.1099/mic.0.000523] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Moraxella catarrhalis is a human-restricted opportunistic bacterial pathogen of the respiratory mucosa. It frequently colonizes the nasopharynx asymptomatically, but is also an important causative agent of otitis media (OM) in children, and plays a significant role in acute exacerbations of chronic obstructive pulmonary disease (COPD) in adults. As the current treatment options for M. catarrhalis infection in OM and exacerbations of COPD are often ineffective, the development of an efficacious vaccine is warranted. However, no vaccine candidates for M. catarrhalis have progressed to clinical trials, and information regarding the distribution of M. catarrhalis virulence factors and vaccine candidates is inconsistent in the literature. It is largely unknown if virulence is associated with particular strains or subpopulations of M. catarrhalis, or if differences in clinical manifestation can be attributed to the heterogeneous expression of specific M. catarrhalis virulence factors in the circulating population. Further investigation of the distribution of M. catarrhalis virulence factors in the context of carriage and disease is required so that vaccine development may be targeted at relevant antigens that are conserved among disease-causing strains. The challenge of determining which of the proposed M. catarrhalis virulence factors are relevant to human disease is amplified by the lack of a standardized M. catarrhalis typing system to facilitate direct comparisons of worldwide isolates. Here we summarize and evaluate proposed relationships between M. catarrhalis subpopulations and specific virulence factors in the context of colonization and disease, as well as the current methods used to infer these associations.
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Affiliation(s)
- Luke V Blakeway
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Aimee Tan
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Ian R A Peak
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia.,School of Medical Science, Griffith University, Gold Coast, Queensland, Australia
| | - Kate L Seib
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
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8
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Pettigrew MM, Alderson MR, Bakaletz LO, Barenkamp SJ, Hakansson AP, Mason KM, Nokso-Koivisto J, Patel J, Pelton SI, Murphy TF. Panel 6: Vaccines. Otolaryngol Head Neck Surg 2017; 156:S76-S87. [PMID: 28372533 DOI: 10.1177/0194599816632178] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Objective To review the literature on progress regarding (1) effectiveness of vaccines for prevention of otitis media (OM) and (2) development of vaccine antigens for OM bacterial and viral pathogens. Data Sources PubMed database of the National Library of Science. Review Methods We performed literature searches in PubMed for OM pathogens and candidate vaccine antigens, and we restricted the searches to articles in English that were published between July 2011 and June 2015. Panel members reviewed literature in their area of expertise. Conclusions Pneumococcal conjugate vaccines (PCVs) are somewhat effective for the prevention of pneumococcal OM, recurrent OM, OM visits, and tympanostomy tube insertions. Widespread use of PCVs has been associated with shifts in pneumococcal serotypes and bacterial pathogens associated with OM, diminishing PCV effectiveness against AOM. The 10-valent pneumococcal vaccine containing Haemophilus influenzae protein D (PHiD-CV) is effective for pneumococcal OM, but results from studies describing the potential impact on OM due to H influenzae have been inconsistent. Progress in vaccine development for H influenzae, Moraxella catarrhalis, and OM-associated respiratory viruses has been limited. Additional research is needed to extend vaccine protection to additional pneumococcal serotypes and other otopathogens. There are likely to be licensure challenges for protein-based vaccines, and data on correlates of protection for OM vaccine antigens are urgently needed. Implications for Practice OM continues to be a significant health care burden globally. Prevention is preferable to treatment, and vaccine development remains an important goal. As a polymicrobial disease, OM poses significant but not insurmountable challenges for vaccine development.
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Affiliation(s)
- Melinda M Pettigrew
- 1 Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven Connecticut, USA
| | | | - Lauren O Bakaletz
- 3 Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, and Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | | | | | - Kevin M Mason
- 3 Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, and Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | | | - Janak Patel
- 7 University of Texas Medical Branch, Galveston, Texas, USA
| | - Stephen I Pelton
- 8 Boston University School of Medicine, Boston, Massachusetts, USA
| | - Timothy F Murphy
- 9 University at Buffalo, The State University of New York, Buffalo, New York, USA
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Röttgerding F, Wagemakers A, Koetsveld J, Fingerle V, Kirschfink M, Hovius JW, Zipfel PF, Wallich R, Kraiczy P. Immune evasion of Borrelia miyamotoi: CbiA, a novel outer surface protein exhibiting complement binding and inactivating properties. Sci Rep 2017; 7:303. [PMID: 28331202 PMCID: PMC5428533 DOI: 10.1038/s41598-017-00412-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 02/27/2017] [Indexed: 12/13/2022] Open
Abstract
Borrelia (B.) miyamotoi, an emerging tick-borne relapsing fever spirochete, resists complement-mediated killing. To decipher the molecular principles of immune evasion, we sought to identify determinants contributing to complement resistance. Employing bioinformatics, we identified a gene encoding for a putative Factor H-binding protein, termed CbiA (complement binding and inhibitory protein A). Functional analyses revealed that CbiA interacted with complement regulator Factor H (FH), C3, C3b, C4b, C5, and C9. Upon binding to CbiA, FH retained its cofactor activity for Factor I-mediated inactivation of C3b. The Factor H-binding site within CbiA was mapped to domain 20 whereby the C-terminus of CbiA was involved in FH binding. Additionally, CbiA directly inhibited the activation of the classical pathway and the assembly of the terminal complement complex. Of importance, CbiA displayed inhibitory activity when ectopically produced in serum-sensitive B. garinii G1, rendering this surrogate strain resistant to human serum. In addition, long-term in vitro cultivation lead to an incremental loss of the cbiA gene accompanied by an increase in serum susceptibility. In conclusion, our data revealed a dual strategy of B. miyamotoi to efficiently evade complement via CbiA, which possesses complement binding and inhibitory activities.
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Affiliation(s)
- Florian Röttgerding
- Institute of Medical Microbiology and Infection Control, University Hospital of Frankfurt, Frankfurt, Germany
| | - Alex Wagemakers
- Center for Experimental and Molecular Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Joris Koetsveld
- Center for Experimental and Molecular Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Volker Fingerle
- National Reference Center for Borrelia, Oberschleißheim, Germany
| | | | - Joppe W Hovius
- Center for Experimental and Molecular Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany.,Friedrich Schiller University, Jena, Germany
| | - Reinhard Wallich
- Institute of Immunology, University of Heidelberg, Heidelberg, Germany
| | - Peter Kraiczy
- Institute of Medical Microbiology and Infection Control, University Hospital of Frankfurt, Frankfurt, Germany.
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10
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Jusko M, Miedziak B, Ermert D, Magda M, King BC, Bielecka E, Riesbeck K, Eick S, Potempa J, Blom AM. FACIN, a Double-Edged Sword of the Emerging Periodontal Pathogen Filifactor alocis: A Metabolic Enzyme Moonlighting as a Complement Inhibitor. THE JOURNAL OF IMMUNOLOGY 2016; 197:3245-3259. [PMID: 27638863 DOI: 10.4049/jimmunol.1600739] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 08/20/2016] [Indexed: 02/01/2023]
Abstract
Periodontal disease is one of the most common inflammatory infectious diseases worldwide and it is associated with other syndromes, such as cardiovascular disease or rheumatoid arthritis. Recent advances in sequencing allowed for identification of novel periodontopathogens such as Gram-positive Filifactor alocis, but its virulence mechanisms remain largely unknown. We confirmed that F. alocis is a prevalent species in periodontitis patients, and we also observed strong correlation of this bacterium with clinical parameters, highlighting its role in the pathogenesis of the disease. Further, we found that preincubation of human serum with F. alocis resulted in abolished bactericidal activity and that F. alocis was surviving readily in full blood. We demonstrated that one of the key contributors to F. alocis complement resistance is a unique protein, FACIN (F. alocis complement inhibitor), which binds to C3, resulting in suppression of all complement pathways. Interestingly, FACIN is a nonclassical cell surface protein, a cytosolic enzyme acetylornithine transaminase, for which we now identified a moonlighting function. FACIN binds to C3 alone, but more importantly it also captures activated complement factor 3 within the complex with factor B, thereby locking in the convertase in an inactive state. Because of the indispensable role of alternative pathway convertase in amplifying complement cascades, its inhibition by FACIN results in a very potent downregulation of activated complement factor 3 opsonization on the pathogen surface, accompanied by reduction of downstream C5 cleavage.
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Affiliation(s)
- Monika Jusko
- Section of Protein Chemistry, Department of Translational Medicine, Lund University, 205 02 Malmö, Sweden
| | - Beata Miedziak
- Section of Protein Chemistry, Department of Translational Medicine, Lund University, 205 02 Malmö, Sweden
| | - David Ermert
- Section of Protein Chemistry, Department of Translational Medicine, Lund University, 205 02 Malmö, Sweden
| | - Michal Magda
- Section of Protein Chemistry, Department of Translational Medicine, Lund University, 205 02 Malmö, Sweden
| | - Ben C King
- Section of Protein Chemistry, Department of Translational Medicine, Lund University, 205 02 Malmö, Sweden
| | - Ewa Bielecka
- Section of Protein Chemistry, Department of Translational Medicine, Lund University, 205 02 Malmö, Sweden.,Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland
| | - Kristian Riesbeck
- Section of Clinical Microbiology, Department of Translational Medicine, Lund University, 202 13 Malmö, Sweden
| | - Sigrun Eick
- Laboratory of Oral Microbiology, Department of Periodontology, University of Bern, 3010 Bern, Switzerland; and
| | - Jan Potempa
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland.,Centre for Oral Health and Systemic Diseases, University of Louisville School of Dentistry, Louisville, KY 40202
| | - Anna M Blom
- Section of Protein Chemistry, Department of Translational Medicine, Lund University, 205 02 Malmö, Sweden;
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11
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Moraxella catarrhalis Binds Plasminogen To Evade Host Innate Immunity. Infect Immun 2015; 83:3458-69. [PMID: 26099590 DOI: 10.1128/iai.00310-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 06/12/2015] [Indexed: 11/20/2022] Open
Abstract
Several bacterial species recruit the complement regulators C4b-binding protein, factor H, and vitronectin, resulting in resistance against the bactericidal activity of human serum. It was recently demonstrated that bacteria also bind plasminogen, which is converted to plasmin that degrades C3b and C5. In this study, we found that a series of clinical isolates (n = 58) of the respiratory pathogen Moraxella catarrhalis, which is commonly isolated from preschool children and adults with chronic obstructive pulmonary disease (COPD), significantly binds human plasminogen. Ubiquitous surface protein A2 (UspA2) and hybrid UspA2 (UspA2H) were identified as the plasminogen-binding factors in the outer membrane proteome of Moraxella. Furthermore, expression of a series of truncated recombinant UspA2 and UspA2H proteins followed by a detailed analysis of protein-protein interactions suggested that the N-terminal head domains bound to the kringle domains of plasminogen. The binding affinity constant (KD) values of full-length UspA2(30-539) (amino acids 30 to 539 of UspA2) and full-length UspA2H(50-720) for immobilized plasminogen were 4.8 × 10(-8) M and 3.13 × 10(-8) M, respectively, as measured by biolayer interferometry. Plasminogen bound to intact M. catarrhalis or to recombinant UspA2/UspA2H was readily accessible for a urokinase plasminogen activator that converted the zymogen into active plasmin, as verified by the specific substrate S-2251 and a degradation assay with fibrinogen. Importantly, plasmin bound at the bacterial surface also degraded C3b and C5, which consequently may contribute to reduced bacterial killing. Our findings suggest that binding of plasminogen to M. catarrhalis may lead to increased virulence and, hence, more efficient colonization of the host.
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Adler NRL, Stevens MP, Dean RE, Saint RJ, Pankhania D, Prior JL, Atkins TP, Kessler B, Nithichanon A, Lertmemongkolchai G, Galyov EE. Systematic mutagenesis of genes encoding predicted autotransported proteins of Burkholderia pseudomallei identifies factors mediating virulence in mice, net intracellular replication and a novel protein conferring serum resistance. PLoS One 2015; 10:e0121271. [PMID: 25830295 PMCID: PMC4382181 DOI: 10.1371/journal.pone.0121271] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 01/29/2015] [Indexed: 01/12/2023] Open
Abstract
Burkholderia pseudomallei is the causative agent of the severe tropical disease melioidosis, which commonly presents as sepsis. The B. pseudomallei K96243 genome encodes eleven predicted autotransporters, a diverse family of secreted and outer membrane proteins often associated with virulence. In a systematic study of these autotransporters, we constructed insertion mutants in each gene predicted to encode an autotransporter and assessed them for three pathogenesis-associated phenotypes: virulence in the BALB/c intra-peritoneal mouse melioidosis model, net intracellular replication in J774.2 murine macrophage-like cells and survival in 45% (v/v) normal human serum. From the complete repertoire of eleven autotransporter mutants, we identified eight mutants which exhibited an increase in median lethal dose of 1 to 2-log10 compared to the isogenic parent strain (bcaA, boaA, boaB, bpaA, bpaC, bpaE, bpaF and bimA). Four mutants, all demonstrating attenuation for virulence, exhibited reduced net intracellular replication in J774.2 macrophage-like cells (bimA, boaB, bpaC and bpaE). A single mutant (bpaC) was identified that exhibited significantly reduced serum survival compared to wild-type. The bpaC mutant, which demonstrated attenuation for virulence and net intracellular replication, was sensitive to complement-mediated killing via the classical and/or lectin pathway. Serum resistance was rescued by in trans complementation. Subsequently, we expressed recombinant proteins of the passenger domain of four predicted autotransporters representing each of the phenotypic groups identified: those attenuated for virulence (BcaA), those attenuated for virulence and net intracellular replication (BpaE), the BpaC mutant with defects in virulence, net intracellular replication and serum resistance and those displaying wild-type phenotypes (BatA). Only BcaA and BpaE elicited a strong IFN-γ response in a restimulation assay using whole blood from seropositive donors and were recognised by seropositive human sera from the endemic area. To conclude, several predicted autotransporters contribute to B. pseudomallei virulence and BpaC may do so by conferring resistance against complement-mediated killing.
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Affiliation(s)
- Natalie R. Lazar Adler
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Mark P. Stevens
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, United Kingdom
| | - Rachel E. Dean
- Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, United Kingdom
| | - Richard J. Saint
- Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, United Kingdom
| | - Depesh Pankhania
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Joann L. Prior
- Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, United Kingdom
| | - Timothy P. Atkins
- Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, United Kingdom
- School of Biosciences, Geoffrey Pope Building, University of Exeter, Exeter, United Kingdom
| | - Bianca Kessler
- The Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Arnone Nithichanon
- The Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Ganjana Lertmemongkolchai
- The Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Edouard E. Galyov
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
- * E-mail:
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Augustyniak D, Piekut M, Majkowska-Skrobek G, Skała J. Bactericidal, opsonophagocytic and anti-adhesive effectiveness of cross-reactive antibodies against Moraxella catarrhalis. Pathog Dis 2015; 73:ftu026. [PMID: 25743473 DOI: 10.1093/femspd/ftu026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Moraxella catarrhalis is a human-restricted significant respiratory tract pathogen. The bacteria accounts for 15-20% of cases of otitis media in children and is an important causative agent of infectious exacerbations of chronic obstructive pulmonary disease in adults. The acquisition of new M. catarrhalis strains plays a central role in the pathogenesis of both mentioned disorders. The antibody-dependent immune response to this pathogen is critical for its effective elimination. Thus, the knowledge about the protective threshold of cross-reactive antibodies with defined functionality seems to be important. The complex analysis of broad-spectrum effectiveness of cross-reactive antibodies against M. catarrhalis has never been performed. The goal of the present study was to demonstrate and compare the bactericidal, opsonophagocytic and blocking function of cross-reacting antibodies produced in response to this bacterium or purified outer membrane proteins incorporated in Zwittergent-based micelles. The multivalent immunogens were used in order to better mimic the natural response of the host. The demonstrated broad-spectrum effectiveness of cross-reactive antibodies in pathogen eradication or inhibition strongly indicates that this pool of antibodies by recognition of pivotal shared M. catarrhalis surface epitopes seems to be an essential additional source to control host-microbe interaction.
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Affiliation(s)
- Daria Augustyniak
- Department of Pathogen Biology and Immunology, Institute of Genetics and Microbiology, University of Wroclaw, Przybyszewskiego 63/77, 51-148 Wroclaw, Poland;
| | - Monika Piekut
- Department of Pathogen Biology and Immunology, Institute of Genetics and Microbiology, University of Wroclaw, Przybyszewskiego 63/77, 51-148 Wroclaw, Poland
| | - Grażyna Majkowska-Skrobek
- Department of Pathogen Biology and Immunology, Institute of Genetics and Microbiology, University of Wroclaw, Przybyszewskiego 63/77, 51-148 Wroclaw, Poland
| | - Jacek Skała
- Department of Genetics, Institute of Genetics and Microbiology, University of Wroclaw, Przybyszewskiego 63/77, 51-148 Wroclaw, Poland
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Xie Q, Brackenbury LS, Hill DJ, Williams NA, Qu X, Virji M. Moraxella catarrhalis adhesin UspA1-derived recombinant fragment rD-7 induces monocyte differentiation to CD14+CD206+ phenotype. PLoS One 2014; 9:e90999. [PMID: 24599281 PMCID: PMC3944954 DOI: 10.1371/journal.pone.0090999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 02/06/2014] [Indexed: 12/04/2022] Open
Abstract
Circulating monocytes in the bloodstream typically migrate to other tissues and differentiate into tissue resident macrophages, the process being determined by the constituents of the microenvironments encountered. These may include microbes and their products. In this study, we investigated whether Moraxella catarrhalis Ubiquitous Surface Protein A1 (UspA1), known to bind to a widely expressed human cell surface receptor CEACAM1, influences monocyte differentiation as receptor engagement has been shown to have profound effects on monocytes. We used the recombinant molecules corresponding to the regions of UspA1 which either bind (rD-7; UspA1527–665) or do not bind (r6–8; UspA1659–863) to CEACAM1 and investigated their effects on CD206, CD80 and CD86 expression on freshly isolated human CD14+ monocytes from peripheral blood mononuclear cells (PBMC). Exposure to rD-7, but not r6–8, biased monocyte differentiation towards a CD14+CD206+ phenotype, with reduced CD80 expression. Monocytes treated with rD-7 also secreted high levels of IL-1ra and chemokine IL-8 but not IL-10 or IL-12p70. The effects of rD-7 were independent of any residual endotoxin. Unexpectedly, these effects of rD-7 were also independent of its ability to bind to CEACAM1, as monocyte pre-treatment with the anti-CEACAM antibody A0115 known to inhibit rD-7 binding to the receptor, did not affect rD-7-driven differentiation. Further, another control protein rD-7/D (a mutant form of rD-7, known not to bind to CEACAMs), also behaved as the parent molecule. Our data suggest that specific regions of M. catarrhalis adhesin UspA1 may modulate inflammation during infection through a yet unknown receptor on monocytes.
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Affiliation(s)
- Qi Xie
- Institute of Basic Medical Sciences, Qilu Hospital, Shandong University, Jinan, Shandong, P.R. China
| | - Louise S. Brackenbury
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Darryl J. Hill
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Neil A. Williams
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
- * E-mail: (XQ); (NW)
| | - Xun Qu
- Institute of Basic Medical Sciences, Qilu Hospital, Shandong University, Jinan, Shandong, P.R. China
- * E-mail: (XQ); (NW)
| | - Mumtaz Virji
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
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Chen Q, Wiesener M, Eberhardt HU, Hartmann A, Uzonyi B, Kirschfink M, Amann K, Buettner M, Goodship T, Hugo C, Skerka C, Zipfel PF. Complement factor H-related hybrid protein deregulates complement in dense deposit disease. J Clin Invest 2013; 124:145-55. [PMID: 24334459 DOI: 10.1172/jci71866] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 10/07/2013] [Indexed: 12/16/2022] Open
Abstract
The renal disorder C3 glomerulopathy with dense deposit disease (C3G-DDD) pattern results from complement dysfunction and primarily affects children and young adults. There is no effective treatment, and patients often progress to end-stage renal failure. A small fraction of C3G-DDD cases linked to factor H or C3 gene mutations as well as autoantibodies have been reported. Here, we examined an index family with 2 patients with C3G-DDD and identified a chromosomal deletion in the complement factor H-related (CFHR) gene cluster. This deletion resulted in expression of a hybrid CFHR2-CFHR5 plasma protein. The recombinant hybrid protein stabilized the C3 convertase and reduced factor H-mediated convertase decay. One patient was refractory to plasma replacement and exchange therapy, as evidenced by the hybrid protein quickly returning to pretreatment plasma levels. Subsequently, complement inhibitors were tested on serum from the patient for their ability to block activity of CFHR2-CFHR5. Soluble CR1 restored defective C3 convertase regulation; however, neither eculizumab nor tagged compstatin had any effect. Our findings provide insight into the importance of CFHR proteins for C3 convertase regulation and identify a genetic variation in the CFHR gene cluster that promotes C3G-DDD. Monitoring copy number and sequence variations in the CFHR gene cluster in C3G-DDD and kidney patients with C3G-DDD variations will help guide treatment strategies.
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Ruiz-Ranwez V, Posadas DM, Estein SM, Abdian PL, Martin FA, Zorreguieta A. The BtaF trimeric autotransporter of Brucella suis is involved in attachment to various surfaces, resistance to serum and virulence. PLoS One 2013; 8:e79770. [PMID: 24236157 PMCID: PMC3827427 DOI: 10.1371/journal.pone.0079770] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 10/02/2013] [Indexed: 02/02/2023] Open
Abstract
The adhesion of bacterial pathogens to host cells is an event that determines infection, and ultimately invasion and intracellular multiplication. Several evidences have recently shown that this rule is also truth for the intracellular pathogen Brucella. Brucella suis displays the unipolar BmaC and BtaE adhesins, which belong to the monomeric and trimeric autotransporter (TA) families, respectively. It was previously shown that these adhesins are involved in bacterial adhesion to host cells and components of the extracellular matrix (ECM). In this work we describe the role of a new member of the TA family of B. suis (named BtaF) in the adhesive properties of the bacterial surface. BtaF conferred the bacteria that carried it a promiscuous adhesiveness to various ECM components and the ability to attach to an abiotic surface. Furthermore, BtaF was found to participate in bacterial adhesion to epithelial cells and was required for full virulence in mice. Similar to BmaC and BtaE, the BtaF adhesin was expressed in a small subpopulation of bacteria, and in all cases, it was detected at the new pole generated after cell division. Interestingly, BtaF was also implicated in the resistance of B. suis to porcine serum. Our findings emphasize the impact of TAs in the Brucella lifecycle.
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Amdahl H, Jongerius I, Meri T, Pasanen T, Hyvärinen S, Haapasalo K, van Strijp JA, Rooijakkers SH, Jokiranta TS. Staphylococcal Ecb protein and host complement regulator factor H enhance functions of each other in bacterial immune evasion. THE JOURNAL OF IMMUNOLOGY 2013; 191:1775-84. [PMID: 23863906 DOI: 10.4049/jimmunol.1300638] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Staphylococcus aureus is a major human pathogen causing more than a tenth of all septicemia cases and often superficial and deep infections in various tissues. One of the immune evasion strategies of S. aureus is to secrete proteins that bind to the central complement opsonin C3b. One of these, extracellular complement binding protein (Ecb), is known to interfere directly with functions of C3b. Because C3b is also the target of the physiological plasma complement regulator, factor H (FH), we studied the effect of Ecb on the complement regulatory functions of FH. We show that Ecb enhances acquisition of FH from serum onto staphylococcal surfaces. Ecb and FH enhance mutual binding to C3b and also the function of each other in downregulating complement activation. Both Ecb and the C-terminal domains 19-20 of FH bind to the C3d part of C3b. We show that the mutual enhancing effect of Ecb and FH on binding to C3b depends on binding of the FH domain 19 to the C3d part of C3b next to the binding site of Ecb on C3d. Our results show that Ecb, FH, and C3b form a tripartite complex. Upon exposure of serum-sensitive Haemophilus influenzae to human serum, Ecb protected the bacteria, and this effect was enhanced by the addition of the C-terminal domains 19-20 of FH. This finding indicates that the tripartite complex formation could give additional protection to bacteria and that S. aureus is thereby able to use host FH and bacterial Ecb in a concerted action to eliminate C3b at the site of infection.
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Affiliation(s)
- Hanne Amdahl
- Department of Bacteriology and Immunology, Haartman Institute, Research Programs Unit, Immunobiology, University of Helsinki, FIN-00014 Helsinki, Finland
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Moraxella catarrhalis uses a twin-arginine translocation system to secrete the β-lactamase BRO-2. BMC Microbiol 2013; 13:140. [PMID: 23782650 PMCID: PMC3695778 DOI: 10.1186/1471-2180-13-140] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 06/10/2013] [Indexed: 12/13/2022] Open
Abstract
Background Moraxella catarrhalis is a human-specific gram-negative bacterium readily isolated from the respiratory tract of healthy individuals. The organism also causes significant health problems, including 15-20% of otitis media cases in children and ~10% of respiratory infections in adults with chronic obstructive pulmonary disease. The lack of an efficacious vaccine, the rapid emergence of antibiotic resistance in clinical isolates, and high carriage rates reported in children are cause for concern. Virtually all Moraxella catarrhalis isolates are resistant to β-lactam antibiotics, which are generally the first antibiotics prescribed to treat otitis media in children. The enzymes responsible for this resistance, BRO-1 and BRO-2, are lipoproteins and the mechanism by which they are secreted to the periplasm of M. catarrhalis cells has not been described. Results Comparative genomic analyses identified M. catarrhalis gene products resembling the TatA, TatB, and TatC proteins of the well-characterized Twin Arginine Translocation (TAT) secretory apparatus. Mutations in the M. catarrhalis tatA, tatB and tatC genes revealed that the proteins are necessary for optimal growth and resistance to β-lactams. Site-directed mutagenesis was used to replace highly-conserved twin arginine residues in the predicted signal sequence of M. catarrhalis strain O35E BRO-2, which abolished resistance to the β-lactam antibiotic carbanecillin. Conclusions Moraxella catarrhalis possesses a TAT secretory apparatus, which plays a key role in growth of the organism and is necessary for secretion of BRO-2 into the periplasm where the enzyme can protect the peptidoglycan cell wall from the antimicrobial activity of β-lactam antibiotics.
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Murphy TF, Chonmaitree T, Barenkamp S, Kyd J, Nokso-Koivisto J, Patel JA, Heikkinen T, Yamanaka N, Ogra P, Swords WE, Sih T, Pettigrew MM. Panel 5: Microbiology and immunology panel. Otolaryngol Head Neck Surg 2013; 148:E64-89. [PMID: 23536533 DOI: 10.1177/0194599812459636] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE The objective is to perform a comprehensive review of the literature from January 2007 through June 2011 on the virology, bacteriology, and immunology related to otitis media. DATA SOURCES PubMed database of the National Library of Medicine. REVIEW METHODS Three subpanels with co-chairs comprising experts in the virology, bacteriology, and immunology of otitis media were formed. Each of the panels reviewed the literature in their respective fields and wrote draft reviews. The reviews were shared with all panel members, and a second draft was created. The entire panel met at the 10th International Symposium on Recent Advances in Otitis Media in June 2011 and discussed the review and refined the content further. A final draft was created, circulated, and approved by the panel. CONCLUSION Excellent progress has been made in the past 4 years in advancing an understanding of the microbiology and immunology of otitis media. Advances include laboratory-based basic studies, cell-based assays, work in animal models, and clinical studies. IMPLICATIONS FOR PRACTICE The advances of the past 4 years formed the basis of a series of short-term and long-term research goals in an effort to guide the field. Accomplishing these goals will provide opportunities for the development of novel interventions, including new ways to better treat and prevent otitis media.
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Affiliation(s)
- Timothy F Murphy
- Clinical and Translational Research Center, University at Buffalo, State University of New York, Buffalo, New York 14203, USA.
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Pelton SI, Pettigrew MM, Barenkamp SJ, Godfroid F, Grijalva CG, Leach A, Patel J, Murphy TF, Selak S, Bakaletz LO. Panel 6: Vaccines. Otolaryngol Head Neck Surg 2013; 148:E90-101. [PMID: 23536534 DOI: 10.1177/0194599812466535] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
OBJECTIVE To update progress on the effectiveness of vaccine for prevention of acute otitis media (AOM) and identification of promising candidate antigens against Streptococcus pneumoniae, nontypeable Haemophilus influenzae, and Moraxella catarrhalis. REVIEW METHODS Literature searches were performed in OvidSP and PubMed restricted to articles published between June 2007 and September 2011. Search terms included otitis media, vaccines, vaccine antigens, and each of the otitis pathogens and candidate antigens identified in the ninth conference report. CONCLUSIONS The current report provides further evidence for the effectiveness of pneumococcal conjugate vaccines (PCVs) in the prevention of otitis media. Observational studies demonstrate a greater decline in AOM episodes than reported in clinical efficacy trials. Unmet challenges include extending protection to additional serotypes and additional pathogens, the need to prevent early episodes, the development of correlates of protection for protein antigens, and the need to define where an otitis media vaccine strategy fits with priorities for child health. IMPLICATIONS FOR PRACTICE Acute otitis media continues to be a burden on children and families, especially those who suffer from frequent recurrences. The 7-valent PCV (PCV7) has reduced the burden of disease as well as shifted the pneumococcal serotypes and the distribution of otopathogens currently reported in children with AOM. Antibiotic resistance remains an ongoing challenge. Multiple candidate antigens have demonstrated the necessary requirements of conservation, surface exposure, immunogenicity, and protection in animal models. Further research on the role of each antigen in pathogenesis, in the development of correlates of protection in animal models, and in new adjuvants to elicit responses in the youngest infants is likely to be productive and permit more antigens to move into human clinical trials.
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Affiliation(s)
- Stephen I Pelton
- Boston University School of Medicine, Boston, Massachusetts, USA.
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Potempa M, Potempa J. Protease-dependent mechanisms of complement evasion by bacterial pathogens. Biol Chem 2013; 393:873-88. [PMID: 22944688 DOI: 10.1515/hsz-2012-0174] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 05/06/2012] [Indexed: 12/11/2022]
Abstract
The human immune system has evolved a variety of mechanisms for the primary task of neutralizing and eliminating microbial intruders. As the first line of defense, the complement system is responsible for rapid recognition and opsonization of bacteria, presentation to phagocytes and bacterial cell killing by direct lysis. All successful human pathogens have mechanisms of circumventing the antibacterial activity of the complement system and escaping this stage of the immune response. One of the ways in which pathogens achieve this is the deployment of proteases. Based on the increasing number of recent publications in this area, it appears that proteolytic inactivation of the antibacterial activities of the complement system is a common strategy of avoiding targeting by this arm of host innate immune defense. In this review, we focus on those bacteria that deploy proteases capable of degrading complement system components into non-functional fragments, thus impairing complement-dependent antibacterial activity and facilitating pathogen survival inside the host.
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Affiliation(s)
- Michal Potempa
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland.
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Su YC, Singh B, Riesbeck K. Moraxella catarrhalis: from interactions with the host immune system to vaccine development. Future Microbiol 2013; 7:1073-100. [PMID: 22953708 DOI: 10.2217/fmb.12.80] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Moraxella catarrhalis is a human-restricted commensal that over the last two decades has developed into an emerging respiratory tract pathogen. The bacterial species is equipped with various adhesins to facilitate its colonization. Successful evasion of the human immune system is a prerequisite for Moraxella infection. This strategy involves induction of an excessive proinflammatory response, intervention of granulocyte recruitment to the infection site, activation of selected pattern recognition receptors and cellular adhesion molecules to counteract the host bacteriolytic attack, as well as, finally, reprogramming of antigen presenting cells. Host immunomodulator molecules are also exploited by Moraxella to aid in resistance against complement killing and host bactericidal molecules. Thus, breaking the basis of Moraxella immune evasion mechanisms is fundamental for future invention of effective therapy in controlling Moraxella infection.
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Affiliation(s)
- Yu-Ching Su
- Medical Microbiology, Department of Laboratory Medicine Malmö, Lund University, Skåne University Hospital, Malmö, Sweden
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