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Wahlenmayer ER, Hammers DE. Streptococcal peptides and their roles in host-microbe interactions. Front Cell Infect Microbiol 2023; 13:1282622. [PMID: 37915845 PMCID: PMC10617681 DOI: 10.3389/fcimb.2023.1282622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 10/02/2023] [Indexed: 11/03/2023] Open
Abstract
The genus Streptococcus encompasses many bacterial species that are associated with hosts, ranging from asymptomatic colonizers and commensals to pathogens with a significant global health burden. Streptococci produce numerous factors that enable them to occupy their host-associated niches, many of which alter their host environment to the benefit of the bacteria. The ability to manipulate host immune systems to either evade detection and clearance or induce a hyperinflammatory state influences whether bacteria are able to survive and persist in a given environment, while also influencing the propensity of the bacteria to cause disease. Several bacterial factors that contribute to this inter-species interaction have been identified. Recently, small peptides have become increasingly appreciated as factors that contribute to Streptococcal relationships with their hosts. Peptides are utilized by streptococci to modulate their host environment in several ways, including by directly interacting with host factors to disrupt immune system function and signaling to other bacteria to control the expression of genes that contribute to immune modulation. In this review, we discuss the many contributions of Streptococcal peptides in terms of their ability to contribute to pathogenesis and disruption of host immunity. This discussion will highlight the importance of continuing to elucidate the functions of these Streptococcal peptides and pursuing the identification of new peptides that contribute to modulation of host environments. Developing a greater understanding of how bacteria interact with their hosts has the potential to enable the development of techniques to inhibit these peptides as therapeutic approaches against Streptococcal infections.
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Affiliation(s)
| | - Daniel E. Hammers
- Biology Department, Houghton University, Houghton, NY, United States
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2
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De Gaetano GV, Coppolino F, Lentini G, Famà A, Cullotta C, Raffaele I, Motta C, Teti G, Speziale P, Pietrocola G, Beninati C. Streptococcus pneumoniae
binds collagens and C1q
via
the SSURE repeats of the PfbB adhesin. Mol Microbiol 2022; 117:1479-1492. [PMID: 35570359 PMCID: PMC9328315 DOI: 10.1111/mmi.14920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 04/17/2022] [Accepted: 05/12/2022] [Indexed: 11/29/2022]
Abstract
The binding of Streptococcus pneumoniae to collagen is likely an important step in the pathogenesis of pneumococcal infections, but little is known of the underlying molecular mechanisms. Streptococcal surface repeats (SSURE) are highly conserved protein domains present in cell wall adhesins from different Streptococcus species. We find here that SSURE repeats of the pneumococcal adhesin plasminogen and fibronectin binding protein B (PfbB) bind to various types of collagen. Moreover, deletion of the pfbB gene resulted in a significant impairment of the ability of encapsulated or unencapsulated pneumococci to bind collagen. Notably, a PfbB SSURE domain is also bound to the complement component C1q that bears a collagen‐like domain and promotes adherence of pneumococci to host cells by acting as a bridge between bacteria and epithelial cells. Accordingly, deletion of PfbB or pre‐treatment with anti‐SSURE antibodies markedly decreased pneumococcal binding to C1q as well as C1q‐dependent adherence to epithelial and endothelial cells. Further data indicated that C1q promotes pneumococcal adherence by binding to integrin α2β1. In conclusion, our results indicate that the SSURE domains of the PfbB protein promote interactions of pneumococci with various types of collagen and with C1q. These repeats may be useful targets in strategies to control S. pneumoniae infections.
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Affiliation(s)
| | - Francesco Coppolino
- Department of BiomedicalDental and Imaging SciencesUniversity of MessinaMessinaItaly
| | - Germana Lentini
- Department of Human PathologyUniversity of MessinaMessinaItaly
| | - Agata Famà
- Department of Human PathologyUniversity of MessinaMessinaItaly
| | - Chiara Cullotta
- Department of Human PathologyUniversity of MessinaMessinaItaly
| | - Ivana Raffaele
- Department of Human PathologyUniversity of MessinaMessinaItaly
| | - Chiara Motta
- Department of Molecular MedicineUniversity of PaviaPaviaItaly
| | | | - Pietro Speziale
- Department of Molecular MedicineUniversity of PaviaPaviaItaly
| | | | - Concetta Beninati
- Department of Human PathologyUniversity of MessinaMessinaItaly
- Scylla Biotech SrlMessinaItaly
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3
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Dobrut A, Ochońska D, Brzozowska E, Górska S, Kaszuba-Zwoinska J, Gołda-Cępa M, Gamian A, Brzychczy-Wloch M. Molecular Characteristic, Antibiotic Resistance, and Detection of Highly Immunoreactive Proteins of Group B Streptococcus Strains Isolated From Urinary Tract Infections in Polish Adults. Front Microbiol 2022; 13:809724. [PMID: 35391726 PMCID: PMC8981152 DOI: 10.3389/fmicb.2022.809724] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/21/2022] [Indexed: 12/02/2022] Open
Abstract
Group B streptococcus (GBS) is one of the uropathogens that causes urinary tract infections (UTIs). The aims of this article were molecular characterization, an analysis of antimicrobial susceptibility profiles, adherence to bladder endothelial cells, and the detection of immunoreactive proteins of 94 clinical strains of GBS isolated from adult Polish patients with UTI. Antibiotic susceptibilities were determined by disk diffusion. Serotyping and Alp family genes detection were studied using multiplex PCR. Genetic profiles were determined by pulsed-field gel electrophoresis. The adherence ability of the studied strains was estimated by incubation on human bladder microvascular endothelial cell line. Immunoreactive proteins were studied by immunoblotting. Antibiotic susceptibility investigation revealed that 22% of GBS strains were resistant to erythromycin, whereas 18% demonstrated resistance to clindamycin. cMLSB was present in 76% of the resistant strains, M phenotype was detected in 14%, whereas iMLSB was present for 10%. The most common serotype was serotype III (31%), followed by serotype V (27%), and serotype Ia (17%). The genes that dominated among other Alp genes were: epsilon (29%), alp2 (27%), and rib (23%). The most common co-occurring serotypes and Alp genes were: Ia and epsilon, III and rib, III and alp2, V and alp2, and V and alp3 (p < 0.001). The PFGE method showed high clonality for serotype V and cMLSB (p < 001). The PFGE method showed high clonality for serotype V. Furthermore, this serotype was significantly associated with the cMLSB phenotype (p < 0.001). The most common immunoreactive proteins demonstrated masses of 50 kDa and 45–47 kDa. Although examined GBS isolates showed high genetic diversity, immunoreactive proteins were common for most of the studied GBS isolates, which may indicate their conservation, and allows to consider them as potential immunodiagnostic markers. Although the examined GBS isolates showed high genetic diversity, immunoreactive proteins were shared by most of the studied GBS isolates. It may indicate their conservation, thus allowing to consider them as potential immunodiagnostic markers.
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Affiliation(s)
- Anna Dobrut
- Department of Molecular Medical Microbiology, Chair of Microbiology, Faculty of Medicine, Jagiellonian University Medical College, Kraków, Poland
| | - Dorota Ochońska
- Department of Molecular Medical Microbiology, Chair of Microbiology, Faculty of Medicine, Jagiellonian University Medical College, Kraków, Poland
| | - Ewa Brzozowska
- Laboratory of Medical Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Sabina Górska
- Laboratory of Microbiome Immunobiology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Jolanta Kaszuba-Zwoinska
- Chair of Pathophysiology, Faculty of Medicine, Jagiellonian University Medical College, Kraków, Poland
| | | | - Andrzej Gamian
- Laboratory of Medical Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Monika Brzychczy-Wloch
- Department of Molecular Medical Microbiology, Chair of Microbiology, Faculty of Medicine, Jagiellonian University Medical College, Kraków, Poland
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4
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Dobrut A, Brzychczy-Włoch M. Immunogenic Proteins of Group B Streptococcus-Potential Antigens in Immunodiagnostic Assay for GBS Detection. Pathogens 2021; 11:43. [PMID: 35055991 PMCID: PMC8778278 DOI: 10.3390/pathogens11010043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 12/29/2021] [Accepted: 12/29/2021] [Indexed: 12/21/2022] Open
Abstract
Streptococcus agalactiae (Group B Streptococcus, GBS) is an opportunistic pathogen, which asymptomatically colonizes the gastrointestinal and genitourinary tract of up to one third of healthy adults. Nevertheless, GBS carriage in pregnant women may lead to several health issues in newborns causing life threatening infection, such as sepsis, pneumonia or meningitis. Recommended GBS screening in pregnant women significantly reduced morbidity and mortality in infants. Nevertheless, intrapartum antibiotic prophylaxis, recommended following the detection of carriage or in case of lack of a carriage test result for pregnant women who demonstrate certain risk factors, led to the expansion of the adverse phenomenon of bacterial resistance to antibiotics. In our paper, we reviewed some immunogenic GBS proteins, i.e., Alp family proteins, β protein, Lmb, Sip, BibA, FsbA, ScpB, enolase, elongation factor Tu, IMPDH, and GroEL, which possess features characteristic of good candidates for immunodiagnostic assays for GBS carriage detection, such as immunoreactivity and specificity. We assume that they can be used as an alternative diagnostic method to the presently recommended bacteriological cultivation and MALDI.
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Affiliation(s)
| | - Monika Brzychczy-Włoch
- Department of Molecular Medical Microbiology, Faculty of Medicine, Medical College, Jagiellonian University, 31-121 Krakow, Poland;
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5
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Mancuso G, Midiri A, Beninati C, Zummo S, Biondo C. Protective role of IL-18 in host defenses against group B Streptococcus. Eur J Clin Microbiol Infect Dis 2021; 40:2657-2663. [PMID: 34218324 DOI: 10.1007/s10096-021-04299-y] [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] [Received: 04/08/2021] [Accepted: 06/21/2021] [Indexed: 11/30/2022]
Abstract
The aim of this study was to investigate the role of IL-18, a member of the IL-1 family, in group B Streptococcus (GBS) infection. Both in a neonatal and adult model of GBS infection, IL-18-deficient animals were significantly more susceptible to infection than WT animals. The lack of IL18 was associated with a marked reduction in IFN-γ-levels after bacterial stimulation but did not play a significant role in the recruitment of PMN to sites of GBS infection. Collectively, our data document a fundamental function of IL-18 signaling in boosting the host immune responses against GBS infection.
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Affiliation(s)
- G Mancuso
- Department of Human Pathology, University of Messina, Messina, Italy.
| | - A Midiri
- Department of Human Pathology, University of Messina, Messina, Italy
| | - C Beninati
- Department of Human Pathology, University of Messina, Messina, Italy
| | - S Zummo
- Department of Human Pathology, University of Messina, Messina, Italy
| | - C Biondo
- Department of Human Pathology, University of Messina, Messina, Italy
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6
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Reinscheid F. A new proposal for the causative agent of the sporadic form of Alzheimer's disease. Med Hypotheses 2020; 146:110453. [PMID: 33373829 DOI: 10.1016/j.mehy.2020.110453] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/07/2020] [Accepted: 12/07/2020] [Indexed: 10/22/2022]
Abstract
Group B streptococcus (Streptococcus agalactiae) is proposed as causative agent for the development of the sporadic form of Alzheimer's disease. Using a fibrinogen binding protein, aggregates are formed including A-beta. After triggering Alzheimer's disease by the bacterium, the next down-stream events mainly follow the well known so called A-beta hypothesis. The combination of the two hypotheses is able to explain a number of epidemiological and biochemial aspects of Alzheimer's disease.
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Affiliation(s)
- Frauke Reinscheid
- Institution: GoePharmResearch, Pfaffenstück 16, 37077 Göttingen, Germany.
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7
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Abstract
In the last two decades, phage display technology has been used for investigating complex biological processes and isolating molecules of practical value in several applications. Bacteriophage lambda, representing a classical cloning and expression system, has also been exploited for generating display libraries of small peptides and protein domains. More recently, large cDNA and whole-genome lambda display libraries of human pathogens have been generated for the discovery of new antigens for biomedical applications. Here, we describe the construction of a whole-genome library of a common pathogen-Streptococcus pneumoniae-and the use of this library for the molecular dissection of the human B-cell response against bacterial infection and colonization.
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8
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De Gaetano GV, Pietrocola G, Romeo L, Galbo R, Lentini G, Giardina M, Biondo C, Midiri A, Mancuso G, Venza M, Venza I, Firon A, Trieu-Cuot P, Teti G, Speziale P, Beninati C. The Streptococcus agalactiae cell wall-anchored protein PbsP mediates adhesion to and invasion of epithelial cells by exploiting the host vitronectin/α v integrin axis. Mol Microbiol 2018; 110:82-94. [PMID: 30030946 DOI: 10.1111/mmi.14084] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2018] [Indexed: 01/02/2023]
Abstract
Binding of microbial pathogens to host vitronectin (Vtn) is a common theme in the pathogenesis of invasive infections. In this study, we characterized the role of Vtn in the invasion of mucosal epithelial cells by Streptococcus agalactiae (i.e. group B streptococcus or GBS), a frequent human pathogen. Moreover, we identified PbsP, a previously described plasminogen-binding protein of GBS, as a dual adhesin that can also interact with human Vtn through its streptococcal surface repeat (SSURE) domains. Deletion of the pbsP gene decreases both bacterial adhesion to Vtn-coated inert surfaces and the ability of GBS to interact with epithelial cells. Bacterial adherence to and invasion of epithelial cells were either inhibited or enhanced by cell pretreatment with, respectively, anti-Vtn antibodies or Vtn, confirming the role of Vtn as a GBS ligand on host cells. Finally, antibodies directed against the integrin αv subunit inhibited Vtn-dependent cell invasion by GBS. Collectively, these results indicate that Vtn acts as a bridge between the SSURE domains of PbsP on the GBS surface and host integrins to promote bacterial invasion of epithelial cells. Therefore, inhibition of interactions between PbsP and extracellular matrix components could represent a viable strategy to prevent colonization and invasive disease by GBS.
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Affiliation(s)
- Giuseppe Valerio De Gaetano
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Giampiero Pietrocola
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy
| | - Letizia Romeo
- IRCCS Centro Neurolesi Bonino Pulejo, Messina, Italy
| | - Roberta Galbo
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Germana Lentini
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Miriam Giardina
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Carmelo Biondo
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Angelina Midiri
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Giuseppe Mancuso
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Mario Venza
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Isabella Venza
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Arnaud Firon
- Institut Pasteur, Unite de Biologie des Bacteriés Pathogènes a Gram positif, CNRS ERL6002, 75015, Paris, France
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unite de Biologie des Bacteriés Pathogènes a Gram positif, CNRS ERL6002, 75015, Paris, France
| | - Giuseppe Teti
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy
| | - Pietro Speziale
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy.,Department of Industrial and Information Engineering, University of Pavia, Pavia, Italy
| | - Concetta Beninati
- Metchnikoff Laboratory, Departments of Human Pathology, Medicine, Biomedical Sciences and Chemical Sciences, University of Messina, Messina, Italy.,Scylla Biotech Srl, Messina, Italy
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9
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The plasminogen binding protein PbsP is required for brain invasion by hypervirulent CC17 Group B streptococci. Sci Rep 2018; 8:14322. [PMID: 30254272 PMCID: PMC6156580 DOI: 10.1038/s41598-018-32774-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 08/30/2018] [Indexed: 01/09/2023] Open
Abstract
Streptococcus agalactiae (Group B Streptococcus or GBS) is a frequent cause of serious disease in newborns and adults. Epidemiological evidence indicates a strong association between GBS strains belonging to the hypervirulent CC17 clonal complex and the occurrence of meningitis in neonates. We investigate here the role of PbsP, a cell wall plasminogen binding protein, in colonization of the central nervous system by CC17 GBS. Deletion of pbsP selectively impaired the ability of the CC17 strain BM110 to colonize the mouse brain after intravenous challenge, despite its unchanged capacity to persist at high levels in the blood and to invade the kidneys. Moreover, immunization with a recombinant form of PbsP considerably reduced brain infection and lethality. In vitro, pbsP deletion markedly decreased plasmin-dependent transmigration of BM110 through brain microvascular endothelial cells. Although PbsP was modestly expressed in bacteria grown under standard laboratory conditions, pbsP expression was markedly upregulated during in vivo infection or upon contact with cultured brain endothelial cells. Collectively, our studies indicate that PbsP is a highly conserved Plg binding adhesin, which is functionally important for invasion of the central nervous system by the hypervirulent CC17 GBS. Moreover, this antigen is a promising candidate for inclusion in a universal GBS vaccine.
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10
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Pietrocola G, Arciola CR, Rindi S, Montanaro L, Speziale P. Streptococcus agalactiae Non-Pilus, Cell Wall-Anchored Proteins: Involvement in Colonization and Pathogenesis and Potential as Vaccine Candidates. Front Immunol 2018; 9:602. [PMID: 29686667 PMCID: PMC5900788 DOI: 10.3389/fimmu.2018.00602] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 03/09/2018] [Indexed: 11/13/2022] Open
Abstract
Group B Streptococcus (GBS) remains an important etiological agent of several infectious diseases including neonatal septicemia, pneumonia, meningitis, and orthopedic device infections. This pathogenicity is due to a variety of virulence factors expressed by Streptococcus agalactiae. Single virulence factors are not sufficient to provoke a streptococcal infection, which is instead promoted by the coordinated activity of several pathogenicity factors. Such determinants, mostly cell wall-associated and secreted proteins, include adhesins that mediate binding of the pathogen to host extracellular matrix/plasma ligands and cell surfaces, proteins that cooperate in the invasion of and survival within host cells and factors that neutralize phagocytosis and/or modulate the immune response. The genome-based approaches and bioinformatics tools and the extensive use of biophysical and biochemical methods and animal model studies have provided a great wealth of information on the molecular structure and function of these virulence factors. In fact, a number of new GBS surface-exposed or secreted proteins have been identified (GBS immunogenic bacterial adhesion protein, leucine-rich repeat of GBS, serine-rich repeat proteins), the three-dimensional structures of known streptococcal proteins (αC protein, C5a peptidase) have been solved and an understanding of the pathogenetic role of "old" and new determinants has been better defined in recent years. Herein, we provide an update of our current understanding of the major surface cell wall-anchored proteins from GBS, with emphasis on their biochemical and structural properties and the pathogenetic roles they may have in the onset and progression of host infection. We also focus on the antigenic profile of these compounds and discuss them as targets for therapeutic intervention.
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Affiliation(s)
- Giampiero Pietrocola
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Carla Renata Arciola
- Research Unit on Implant Infections, Rizzoli Orthopaedic Institute, Bologna, Italy.,Department of Experimental, Diagnostic, and Specialty Medicine, University of Bologna, Bologna, Italy
| | - Simonetta Rindi
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Lucio Montanaro
- Research Unit on Implant Infections, Rizzoli Orthopaedic Institute, Bologna, Italy.,Department of Experimental, Diagnostic, and Specialty Medicine, University of Bologna, Bologna, Italy
| | - Pietro Speziale
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia, Pavia, Italy.,Department of Industrial and Information Engineering, University of Pavia, Pavia, Italy
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11
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Domina M, Lanza Cariccio V, Benfatto S, Venza M, Venza I, Borgogni E, Castellino F, Midiri A, Galbo R, Romeo L, Biondo C, Masignani V, Teti G, Felici F, Beninati C. Functional characterization of a monoclonal antibody epitope using a lambda phage display-deep sequencing platform. Sci Rep 2016; 6:31458. [PMID: 27530334 PMCID: PMC4987625 DOI: 10.1038/srep31458] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 07/18/2016] [Indexed: 11/10/2022] Open
Abstract
We have recently described a method, named PROFILER, for the identification of antigenic regions preferentially targeted by polyclonal antibody responses after vaccination. To test the ability of the technique to provide insights into the functional properties of monoclonal antibody (mAb) epitopes, we used here a well-characterized epitope of meningococcal factor H binding protein (fHbp), which is recognized by mAb 12C1. An fHbp library, engineered on a lambda phage vector enabling surface expression of polypeptides of widely different length, was subjected to massive parallel sequencing of the phage inserts after affinity selection with the 12C1 mAb. We detected dozens of unique antibody-selected sequences, the most enriched of which (designated as FrC) could largely recapitulate the ability of fHbp to bind mAb 12C1. Computational analysis of the cumulative enrichment of single amino acids in the antibody-selected fragments identified two overrepresented stretches of residues (H248-K254 and S140-G154), whose presence was subsequently found to be required for binding of FrC to mAb 12C1. Collectively, these results suggest that the PROFILER technology can rapidly and reliably identify, in the context of complex conformational epitopes, discrete “hot spots” with a crucial role in antigen-antibody interactions, thereby providing useful clues for the functional characterization of the epitope.
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Affiliation(s)
| | | | | | - Mario Venza
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Isabella Venza
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | | | | | - Angelina Midiri
- Department of Human Pathology, University of Messina, Messina, Italy
| | - Roberta Galbo
- Department of Biological, Chemical and Environmental Sciences, University of Messina, Messina, Italy
| | - Letizia Romeo
- Department of Human Pathology, University of Messina, Messina, Italy
| | - Carmelo Biondo
- Department of Human Pathology, University of Messina, Messina, Italy
| | | | - Giuseppe Teti
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy.,Charybdis Vaccines Srl, Messina, Italy
| | - Franco Felici
- Department of Biosciences and Territory, University of Molise, Pesche, Isernia, Italy
| | - Concetta Beninati
- Scylla Biotech Srl, Messina, Italy.,Department of Human Pathology, University of Messina, Messina, Italy
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12
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Mohammadi N, Midiri A, Mancuso G, Patanè F, Venza M, Venza I, Passantino A, Galbo R, Teti G, Beninati C, Biondo C. Neutrophils Directly Recognize Group B Streptococci and Contribute to Interleukin-1β Production during Infection. PLoS One 2016; 11:e0160249. [PMID: 27509078 PMCID: PMC4980021 DOI: 10.1371/journal.pone.0160249] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 07/15/2016] [Indexed: 11/29/2022] Open
Abstract
Previous studies have shown that the pro-inflammatory cytokine IL-1β has a crucial role in host defenses against group B streptococcus (GBS), a frequent human pathogen, by recruiting neutrophils to infection sites. We examined here the cell types and mechanisms involved in IL-1β production during infection. Using a GBS-induced peritonitis model in mice, we first found that a large proportion of exudate cells contain intracellular IL-1β by immunofluorescence. Of the IL-1β positive cells, 82 and 7% were neutrophils and macrophages, respectively, suggesting that the former cell type might significantly contribute to IL-1β production. Accordingly, depletion of neutrophils with anti-Ly6G antibodies resulted in a significant reduction in the levels of IL-1β, but not of TNF-α or IL-6. We next found that neutrophils are capable of releasing mature IL-1β and TNF-α directly in response to in vitro stimulation with GBS. The production of pro-IL-1β and TNF-α in these cells required the Toll-like receptor (TLR) adaptor MyD88 and the chaperone protein UNC93B1, which is involved in mobilization of a subfamily of TLRs to the endosomes. Moreover, pro-IL-1β processing and IL-1β release was triggered by GBS hemolysin and required components of the canonical inflammasome, including caspase-1, ASC and NLRP3. Collectively our findings indicate that neutrophils make a significant contribution to IL-1β production during GBS infection, thereby amplifying their own recruitment. These cells directly recognize GBS by means of endosomal TLRs and cytosolic sensors, leading to activation of the caspase-1 inflammasome.
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Affiliation(s)
- Nastaran Mohammadi
- Department of Clinical and Experimental Medicine, University of Messina, 98125, Messina, Italy
| | - Angelina Midiri
- Department of Human Pathology, University of Messina, 98125, Messina, Italy
| | - Giuseppe Mancuso
- Department of Human Pathology, University of Messina, 98125, Messina, Italy
| | - Francesco Patanè
- Department of Human Pathology, University of Messina, 98125, Messina, Italy
| | - Mario Venza
- Department of Clinical and Experimental Medicine, University of Messina, 98125, Messina, Italy
| | - Isabella Venza
- Department of Clinical and Experimental Medicine, University of Messina, 98125, Messina, Italy
| | | | - Roberta Galbo
- Department of Biological, Chemical and Environmental Sciences, University of Messina, 98125, Messina, Italy
| | - Giuseppe Teti
- Department of Clinical and Experimental Medicine, University of Messina, 98125, Messina, Italy
- Charybdis Vaccines Srl, 98125, Messina, Italy
- * E-mail:
| | - Concetta Beninati
- Department of Human Pathology, University of Messina, 98125, Messina, Italy
- Scylla Biotech Srl, 98125, Messina, Italy
| | - Carmelo Biondo
- Department of Human Pathology, University of Messina, 98125, Messina, Italy
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Epitope Mapping of a Monoclonal Antibody Directed against Neisserial Heparin Binding Antigen Using Next Generation Sequencing of Antigen-Specific Libraries. PLoS One 2016; 11:e0160702. [PMID: 27508302 PMCID: PMC4980009 DOI: 10.1371/journal.pone.0160702] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 07/22/2016] [Indexed: 01/07/2023] Open
Abstract
We explore here the potential of a newly described technology, which is named PROFILER and is based on next generation sequencing of gene-specific lambda phage-displayed libraries, to rapidly and accurately map monoclonal antibody (mAb) epitopes. For this purpose, we used a novel mAb (designated 31E10/E7) directed against Neisserial Heparin-Binding Antigen (NHBA), a component of the anti-group B meningococcus Bexsero® vaccine. An NHBA phage-displayed library was affinity-selected with mAb 31E10/E7, followed by massive sequencing of the inserts present in antibody-selected phage pools. Insert analysis identified an amino acid stretch (D91-A128) in the N-terminal domain, which was shared by all of the mAb-enriched fragments. Moreover, a recombinant fragment encompassing this sequence could recapitulate the immunoreactivity of the entire NHBA molecule against mAb 31E10/E7. These results were confirmed using a panel of overlapping recombinant fragments derived from the NHBA vaccine variant and a set of chemically synthetized peptides covering the 10 most frequent antigenic variants. Furthermore, hydrogen-deuterium exchange mass-spectrometry analysis of the NHBA-mAb 31E10/E7 complex was also compatible with mapping of the epitope to the D91-A128 region. Collectively, these results indicate that the PROFILER technology can reliably identify epitope-containing antigenic fragments and requires considerably less work, time and reagents than other epitope mapping methods.
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Cariccio VL, Domina M, Benfatto S, Venza M, Venza I, Faleri A, Bruttini M, Bartolini E, Giuliani MM, Santini L, Brunelli B, Norais N, Borgogni E, Midiri A, Galbo R, Romeo L, Biondo C, Masignani V, Teti G, Felici F, Beninati C. Phage display revisited: Epitope mapping of a monoclonal antibody directed against Neisseria meningitidis adhesin A using the PROFILER technology. MAbs 2016; 8:741-50. [PMID: 26963435 DOI: 10.1080/19420862.2016.1158371] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
There is a strong need for rapid and reliable epitope mapping methods that can keep pace with the isolation of increasingly larger numbers of mAbs. We describe here the identification of a conformational epitope using Phage-based Representation OF ImmunoLigand Epitope Repertoire (PROFILER), a recently developed high-throughput method based on deep sequencing of antigen-specific lambda phage-displayed libraries. A novel bactericidal monoclonal antibody (mAb 9F11) raised against Neisseria meningitidis adhesin A (NadA), an important component of the Bexsero(®) anti-meningococcal vaccine, was used to evaluate the technique in comparison with other epitope mapping methods. The PROFILER technology readily identified NadA fragments that were capable of fully recapitulating the reactivity of the entire antigen against mAb 9F11. Further analysis of these fragments using mutagenesis and hydrogen-deuterium exchange mass-spectrometry allowed us to identify the binding site of mAb 9F11 (A250-D274) and an adjoining sequence (V275-H312) that was also required for the full functional reconstitution of the epitope. These data suggest that, by virtue of its ability to detect a great variety of immunoreactive antigen fragments in phage-displayed libraries, the PROFILER technology can rapidly and reliably identify epitope-containing regions and provide, in addition, useful clues for the functional characterization of conformational mAb epitopes.
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Affiliation(s)
| | | | - Salvatore Benfatto
- b Department of Human Pathology , University of Messina , Messina , Italy
| | - Mario Venza
- c Department Clinical and Experimental Medicine , University of Messina , Messina , Italy
| | - Isabella Venza
- c Department Clinical and Experimental Medicine , University of Messina , Messina , Italy
| | | | - Marco Bruttini
- d GSK Vaccines , Siena , Italy.,e Department of Life Sciences , University of Siena , Siena , Italy
| | | | | | | | | | | | | | - Angelina Midiri
- b Department of Human Pathology , University of Messina , Messina , Italy
| | - Roberta Galbo
- b Department of Human Pathology , University of Messina , Messina , Italy
| | - Letizia Romeo
- b Department of Human Pathology , University of Messina , Messina , Italy
| | - Carmelo Biondo
- b Department of Human Pathology , University of Messina , Messina , Italy
| | | | - Giuseppe Teti
- c Department Clinical and Experimental Medicine , University of Messina , Messina , Italy.,f Charybdis Vaccines Srl , Messina , Italy
| | - Franco Felici
- g Department of Biosciences and Territory , University of Molise , Pesche , Isernia , Italy
| | - Concetta Beninati
- a Scylla Biotech Srl , Messina , Italy.,b Department of Human Pathology , University of Messina , Messina , Italy
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Dangor Z, Kwatra G, Izu A, Adrian P, Cutland CL, Velaphi S, Ballot D, Reubenson G, Zell ER, Lala SG, Madhi SA. Association between maternal Group B Streptococcus surface-protein antibody concentrations and invasive disease in their infants. Expert Rev Vaccines 2015; 14:1651-60. [PMID: 26364978 DOI: 10.1586/14760584.2015.1085307] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVES Group B Streptococcus (GBS) surface-proteins have been shown to be immunogenic and potential vaccine candidates. We aim to determine the association between maternal IgG antibodies to select GBS surface-proteins and invasive GBS disease in their infants. METHODS Using a matched case-control study, maternal antibody levels for GBS-immunogenic bacterial adhesin, fibrinogen-binding protein A and pilus-island (PI) PI-1, PI-2a, PI-2b were compared between infants with invasive GBS disease and well-baby controls. RESULTS The absolute risk of disease did not differ between cases and colonized controls with increasing antibody concentrations for these surface-proteins. There was, however, a relative risk reduction in invasive disease associated with fibrinogen-binding protein A, with an adjusted odds ratio of 0.04 (95% CI: 0.01-0.69) at antibody levels ≥10,000 AU/ml. CONCLUSION We have not demonstrated an association between naturally occurring fibrinogen-binding protein A, GBS-immunogenic bacterial adhesin, and PI surface-protein antibodies and the risk of invasive disease in young infants. These surface-proteins may not be suitable GBS vaccine candidates.
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Affiliation(s)
- Ziyaad Dangor
- a 1 Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,b 2 Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,c 3 Department of Paediatrics & Child Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Gaurav Kwatra
- a 1 Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,b 2 Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Alane Izu
- a 1 Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,b 2 Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Peter Adrian
- a 1 Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,b 2 Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Clare L Cutland
- a 1 Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,b 2 Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Sithembiso Velaphi
- c 3 Department of Paediatrics & Child Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Daynia Ballot
- c 3 Department of Paediatrics & Child Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Gary Reubenson
- c 3 Department of Paediatrics & Child Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | | | - Sanjay G Lala
- c 3 Department of Paediatrics & Child Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Shabir A Madhi
- a 1 Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,b 2 Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,e 5 National Institute for Communicable Diseases: a division of National Health Laboratory Service, Centre for Vaccines and Immunology, Sandringham, South Africa
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16
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Buscetta M, Papasergi S, Firon A, Pietrocola G, Biondo C, Mancuso G, Midiri A, Romeo L, Teti G, Speziale P, Trieu-Cuot P, Beninati C. FbsC, a novel fibrinogen-binding protein, promotes Streptococcus agalactiae-host cell interactions. J Biol Chem 2015; 289:21003-21015. [PMID: 24904056 DOI: 10.1074/jbc.m114.553073] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Streptococcus agalactiae (group B Streptococcus or GBS) is a common cause of invasive infections in newborn infants and adults. The ability of GBS to bind human fibrinogen is of crucial importance in promoting colonization and invasion of host barriers. We characterized here a novel fibrinogen-binding protein of GBS, designated FbsC (Gbs0791), which is encoded by the prototype GBS strain NEM316. FbsC, which bears two bacterial immunoglobulin-like tandem repeat domains and a C-terminal cell wall-anchoring motif (LPXTG), was found to be covalently linked to the cell wall by the housekeeping sortase A. Studies using recombinant FbsC indicated that it binds fibrinogen in a dose-dependent and saturable manner, and with moderate affinity. Expression of FbsC was detected in all clinical GBS isolates, except those belonging to the hypervirulent lineage ST17. Deletion of fbsC decreases NEM316 abilities to adhere to and invade human epithelial and endothelial cells, and to form biofilm in vitro. Notably, bacterial adhesion to fibrinogen and fibrinogen binding to bacterial cells were abolished following fbsC deletion in NEM316. Moreover, the virulence of the fbsC deletion mutant and its ability to colonize the brain were impaired in murine models of infection. Finally, immunization with recombinant FbsC significantly protected mice from lethal GBS challenge. In conclusion, FbsC is a novel fibrinogen-binding protein expressed by most GBS isolates that functions as a virulence factor by promoting invasion of epithelial and endothelial barriers. In addition, the protein has significant immunoprotective activity and may be a useful component of an anti-GBS vaccine.
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Role of Toll-like receptor 13 in innate immune recognition of group B streptococci. Infect Immun 2014; 82:5013-22. [PMID: 25225249 DOI: 10.1128/iai.02282-14] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Murine Toll-like receptor 13 (TLR13), an endosomal receptor that is not present in humans, is activated by an unmethylated motif present in the large ribosomal subunit of bacterial RNA (23S rRNA). Little is known, however, of the impact of TLR13 on antibacterial host defenses. Here we examined the role of this receptor in the context of infection induced by the model pathogen group B streptococcus (GBS). To this end, we used bacterial strains masked from TLR13 recognition by virtue of constitutive expression of the ErmC methyltransferase, which results in dimethylation of the 23S rRNA motif at a critical adenine residue. We found that TLR13-mediated rRNA recognition was required for optimal induction of tumor necrosis factor alpha and nitrous oxide in dendritic cell and macrophage cultures stimulated with heat-killed bacteria or purified bacterial RNA. However, TLR13-dependent recognition was redundant when live bacteria were used as a stimulus. Moreover, masking bacterial rRNA from TLR13 recognition did not increase the ability of GBS to avoid host defenses and replicate in vivo. In contrast, increased susceptibility to infection was observed under conditions in which signaling by all endosomal TLRs was abolished, i.e., in mice with a loss-of-function mutation in the chaperone protein UNC93B1. Our data lend support to the conclusion that TLR13 participates in GBS recognition, although blockade of the function of this receptor can be compensated for by other endosomal TLRs. Lack of selective pressure by bacterial infections might explain the evolutionary loss of TLR13 in humans. However, further studies using different bacterial species are needed to prove this hypothesis.
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Abstract
Signal transduction via MyD88, an adaptor protein engaged by the Toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) family receptors, has a crucial role in host defenses against group B streptococcus (GBS). To examine the contribution of IL-1R signaling to MyD88-dependent host defenses, we analyzed GBS infection in type I IL-1R (IL-1RI)-deficient mice. Most of these animals displayed clinical signs of sepsis and neurological disease and died after a challenge with a bacterial dose that did not cause illness or death in any of the wild-type animals. Moreover, bacterial numbers in the blood and brains of the immunodefective mice were considerably increased. The ability of blood leukocytes or bone marrow-derived macrophages to kill GBS in vitro was not affected by a lack of IL-1RI. However, it was found in a newly developed model of GBS-induced peritoneal inflammation that IL-1 signaling selectively promoted the production of the chemokines KC and MIP-1α and neutrophil recruitment. Moreover, the secretion of KC and MIP-1α, but not tumor necrosis factor alpha, by peritoneal macrophages stimulated with GBS was significantly decreased in the absence of IL-1RI. Accordingly, the number of neutrophils in the blood and the concentration of myeloperoxidase, a neutrophil marker, in infected organs were severely reduced in the immunodefective mice during GBS disease, concomitantly with a reduction in tissue KC and MIP-1α levels. In conclusion, IL-1RI plays a crucial role in host defenses against GBS by inducing the high-level production of chemokines and the subsequent recruitment of neutrophilic polymorphonuclear leukocytes to infection sites. Group B streptococcus (GBS) is a serious and frequent human pathogen. Experimental infection with this bacterium has been widely used to understand the mechanism whereby the body’s first line of defense, represented by cells and molecules of the innate immune system, fights infections. In both humans and mice, defective function of the adaptor molecule MyD88 has been associated with extreme susceptibility to infection by GBS and other extracellular bacteria. We show here that lack of signaling by interleukin-1 (IL-1) cytokines can largely, although not completely, explain the increased susceptibility to infection observed in the absence of MyD88 function. We show, in particular, that IL-1 signaling through the IL-1 receptor promotes the production of the leukocyte attractant chemokines KC and MIP-1α and recruitment of neutrophils to GBS infection sites, thereby enabling these leukocytes to clear the infection. Our findings indicate that stimulation of IL-1 signaling may be useful as an alternative therapeutic strategy to treat GBS infections.
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The interleukin-1β/CXCL1/2/neutrophil axis mediates host protection against group B streptococcal infection. Infect Immun 2014; 82:4508-17. [PMID: 25114117 DOI: 10.1128/iai.02104-14] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous studies have indicated that group B streptococcus (GBS), a frequent human pathogen, potently induces the release of interleukin-1β (IL-1β), an important mediator of inflammatory responses. Since little is known about the role of this cytokine in GBS disease, we analyzed the outcome of infection in IL-1β-deficient mice. These animals were markedly sensitive to GBS infection, with most of them dying under challenge conditions that caused no deaths in wild-type control mice. Lethality was due to the inability of the IL-1β-deficient mice to control local GBS replication and dissemination to target organs, such as the brain and the kidneys. Moreover, in a model of inflammation induced by the intraperitoneal injection of killed GBS, a lack of IL-1β was associated with selective impairment in the production of the neutrophil chemokines CXCL1 and CXCL2 and in neutrophil recruitment to the peritoneal cavity. Decreased blood neutrophil counts and impaired neutrophil recruitment to the brain and kidneys were also observed during GBS infection in IL-1β-deficient mice concomitantly with a reduction in CXCL1 and CXCL2 tissue levels. Notably, the hypersusceptibility to GBS infection observed in the immune-deficient animals was recapitulated by neutrophil depletion with anti-Gr1 antibodies. Collectively, our data identify a cytokine circuit that involves IL-1β-induced production of CXCL1 and CXCL2 and leads the recruitment of neutrophils to GBS infection sites. Moreover, our data point to an essential role of these cells in controlling the progression and outcome of GBS disease.
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20
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Wang NY, Patras KA, Seo HS, Cavaco CK, Rösler B, Neely MN, Sullam PM, Doran KS. Group B streptococcal serine-rich repeat proteins promote interaction with fibrinogen and vaginal colonization. J Infect Dis 2014; 210:982-91. [PMID: 24620021 DOI: 10.1093/infdis/jiu151] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Group B streptococcus (GBS) can cause severe disease in susceptible hosts, including newborns, pregnant women, and the elderly. GBS serine-rich repeat (Srr) surface glycoproteins are important adhesins/invasins in multiple host tissues, including the vagina. However, exact molecular mechanisms contributing to their importance in colonization are unknown. We have recently determined that Srr proteins contain a fibrinogen-binding region (BR) and hypothesize that Srr-mediated fibrinogen binding may contribute to GBS cervicovaginal colonization. In this study, we observed that fibrinogen enhanced wild-type GBS attachment to cervical and vaginal epithelium, and that this was dependent on Srr1. Moreover, purified Srr1-BR peptide bound directly to host cells, and peptide administration in vivo reduced GBS recovery from the vaginal tract. Furthermore, a GBS mutant strain lacking only the Srr1 "latching" domain exhibited decreased adherence in vitro and decreased persistence in a mouse model of GBS vaginal colonization, suggesting the importance of Srr-fibrinogen interactions in the female reproductive tract.
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Affiliation(s)
- Nai-Yu Wang
- Department of Biology and Center for Microbial Sciences, San Diego State University
| | - Kathryn A Patras
- Department of Biology and Center for Microbial Sciences, San Diego State University
| | - Ho Seong Seo
- Division of Infectious Diseases, Veteran Affairs Medical Center and the University of California San Francisco, California Radiation Biotechnology Research Division, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Republic of Korea
| | - Courtney K Cavaco
- Department of Biology and Center for Microbial Sciences, San Diego State University
| | - Berenice Rösler
- Department of Biology and Center for Microbial Sciences, San Diego State University
| | - Melody N Neely
- Department of Immunology and Microbiology, School of Medicine, Wayne State University, Detroit, Michigan
| | - Paul M Sullam
- Division of Infectious Diseases, Veteran Affairs Medical Center and the University of California San Francisco, California
| | - Kelly S Doran
- Department of Biology and Center for Microbial Sciences, San Diego State University Department of Pediatrics, University of California San Diego School of Medicine, La Jolla
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