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Aghababa H, Loh JMS, Proft T. Methods to Analyze the Contribution of Complement Evasion Factor (CEF) to Streptococcus pyogenes Virulence. Methods Mol Biol 2023; 2674:119-129. [PMID: 37258964 DOI: 10.1007/978-1-0716-3243-7_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Group A Streptococcus (GAS, Streptococcus pyogenes) is an exclusively human pathogen that causes a range of diseases, including pharyngitis, tonsillitis, impetigo, erysipelas, necrotizing fasciitis, and toxic shock syndrome. Post-streptococcal sequelae include acute rheumatic fever and rheumatic heart disease. The bacterium produces a large arsenal of virulence factors that contribute to host tissue adhesion/colonization, bacterial spread, and host immune evasion. Immune evasion factors include proteins that interfere with complement, a system of plasma proteins that are activated by pathogens resulting in a variety of reactions on the surface of the pathogen. This leads to the activation of active components with a variety of effector functions, such as cell lysis, opsonization, and chemotaxis of phagocytes to the site of infection. We have recently identified a novel "complement evasion factor" (CEF) in S. pyogenes. CEF directly interacts with complement proteins C1r, C1s, C3, and C5, interrupts all three complement pathways, and prevents opsonization of the bacterial surface with C3b. We here present methods used to analyze the complement interference of CEF.
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Affiliation(s)
- Haniyeh Aghababa
- Department of Molecular Medicine & Pathology, School of Medical Sciences and Maurice Wilkins Centre for Biomolecular Discovery, The University of Auckland, Auckland, New Zealand
| | - Jacelyn M S Loh
- Department of Molecular Medicine & Pathology, School of Medical Sciences and Maurice Wilkins Centre for Biomolecular Discovery, The University of Auckland, Auckland, New Zealand
| | - Thomas Proft
- Department of Molecular Medicine & Pathology, School of Medical Sciences and Maurice Wilkins Centre for Biomolecular Discovery, The University of Auckland, Auckland, New Zealand.
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Functional Characterisation of Two Novel Deacetylases from Streptococcus pyogenes. MICROBIOLOGY RESEARCH 2022. [DOI: 10.3390/microbiolres13020025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Streptococcus pyogenes (Group A Streptococcus, GAS) is an exclusively human pathogen that causes a wide range of diseases. We have identified two novel proteins, Spy1094 and Spy1370, which show sequence similarity with peptidoglycan deacetylases (PGDAs) from other streptococcal species like S. pneumoniae and S. iniae, that represent important virulence factors. Recombinant Spy1094 and Spy1370 were active at a wide pH range (pH 4.0–9.0) and showed metal ion-dependence, with the highest activities observed in the presence of Mn2+, Mg2+and Zn2+. The enzymes showed typical Michaelis–Menten saturation kinetics with the pseudo-substrate GlcNAc3. Binding affinities for rSpy1094 and rSpy1370 were high (Km = 2.2 ± 0.9 μM and 3.1 ± 1.1 μM, respectively), but substrate turnover was low (Kcat = 0.0075/s and 0.0089/s, respectively) suggesting that peptidoglycan might not be the preferred target for deacetylation. Both enzymes were expressed during bacterial growth.
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Hashemzadeh MS, Tapeh BE, Mirhosseini SA. The Role of Bacterial Superantigens in the Immune Response: From Biology to Cancer Treatment. CURRENT CANCER THERAPY REVIEWS 2021. [DOI: 10.2174/1573394716666200812150402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aims:
Encouraging results have been indicated preclinically and in patients using the
bacterial superantigen. This review article intends to summarize the role of the superantigens that
have been recently used in the treatment of cancer. In addition, the vector systems, including lentiviral
vectors, adeno-associated vector systems and retroviral vectors that are increasingly being
used in basic and applied research, were discussed. Most importantly, the new CRISPR technique
has also been discussed in this literature review.
Discussion:
More successful therapies can be achieved by manipulating bacterial vector systems
through incorporating genes related to the superantigens and cytokines. The products of SAg and
cytokine genes contribute to the strong stimulation of the immune system against tumor cells. They
bind to MHC II molecules as well as the V beta regions of TCR and lead to the production of IL2
and other cytokines, the activation of antigen-presenting cells and T lymphocytes. Additionally, superantigens
can be used to eradicate tumor cells. Better results in cancer treatment can be achieved
by transferring superantigen genes and subsequent strong immune stimulation along with other cancer
immunotherapy agents.
Conclusion:
Superantigens induce the proliferation of T lymphocytes and antigen-presenting cells
by binding to MHCII molecules and V beta regions in T cell receptors. Therefore, the presentation
of tumor cell antigens is increased. Additionally, the production of important cytokines by T cells
and APCs contributes to the stimulation of immune response against tumor cells. The manipulation
of bacterial vector systems through incorporating genesrelated to SAgs and other immune response
factors is a good strategy for the immune system stimulating and eradicating tumor cells along with
other immunotherapy agents.
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Affiliation(s)
- Mohammad S. Hashemzadeh
- Nanobiotechnology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Behnam E.G. Tapeh
- Applied Microbiology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Seyed A. Mirhosseini
- Applied Microbiology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
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Heterogeneity in FoxP3- and GARP/LAP-Expressing T Regulatory Cells in an HLA Class II Transgenic Murine Model of Necrotizing Soft Tissue Infections by Group A Streptococcus. Infect Immun 2018; 86:IAI.00432-18. [PMID: 30224551 DOI: 10.1128/iai.00432-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 09/03/2018] [Indexed: 11/20/2022] Open
Abstract
Invasive group A streptococcus (GAS) infections include necrotizing soft tissue infections (NSTI) and streptococcal toxic shock syndrome (STSS). We have previously shown that host HLA class II allelic variations determine the risk for necrotizing fasciitis (NF), a dominant subgroup of NSTI, and STSS by modulating responses to GAS superantigens (SAgs). SAgs are pivotal mediators of uncontrolled T-cell activation, triggering a proinflammatory cytokine storm in the host. FoxP3-expressing CD4+ CD25+ T regulatory cells (Tregs) comprise phenotypically and functionally heterogeneous subsets with a profound ability to suppress inflammatory responses. Specifically, activated Tregs, which express glycoprotein A repetitions predominant (GARP) and display latent transforming growth factor β1 (TGF-β1) complexes (latency-associated peptide [LAP]), exhibit strong immunosuppressive functions. The significance of Tregs that may participate in suppressing inflammatory responses during NSTI is unknown. Here, we phenotypically characterized FoxP3/GARP/LAP-expressing Tregs in GAS-infected or SAg (SmeZ)-stimulated splenocytes from transgenic (tg) mice expressing human HLA-II DRB1*15 (DR15 allele associated with nonsevere NF/STSS-protective responses) or DRB1*0402/DQB1*0302 (DR4/DQ8 alleles associated with neutral risk for combined NF/STSS). We demonstrated both in vivo and in vitro that the neutral-risk allele upregulates expression of CD4+ CD25+ activated effector T cells, with a significantly lower frequency of Foxp3+/GARP+ LAP- but higher frequency of Foxp3- LAP+ Tregs than seen with the protective allele. Additional in vitro studies revealed that the presentation of SmeZ by the neutral-risk allele significantly increases proliferation and expression of effector cytokines gamma interferon (IFN-γ) and interleukin-2 (IL-2) and upregulates CD4+ CD25+ T cell receptors (TCRs) carrying specific Vβ 11 chain (TCRVβ11+) T cells and Th1 transcription factor Tbx21 mRNA levels. Our data suggest that neutral-risk alleles may drive Th1 differentiation while attenuating the induction of Tregs associated with suppressive function.
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A novel staphylococcal enterotoxin B subunit vaccine candidate elicits protective immune response in a mouse model. Toxicon 2017; 131:68-77. [PMID: 28359755 DOI: 10.1016/j.toxicon.2017.03.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 03/21/2017] [Accepted: 03/22/2017] [Indexed: 11/20/2022]
Abstract
Staphylococcal enterotoxin B (SEB), produced by the gram-positive bacterium Staphylococcus aureus, is responsible for food poisoning and toxic shock syndrome, and is considered a potential bioterrorism agent. Unfortunately, still now no approved vaccines are available against SEB. In this study, we constructed a series of nontoxic SEB mutants (mSEBs) and examined whether these mSEBs provide protective immunity against SEB challenge. These mSEB vaccine candidates did not demonstrate superantigen activity in mouse splenocyte cultures. Immunization with the vaccine candidates triggered the production of IgG-antibodies with neutralizing activity. In addition, increased production of IgG1 and IgG3 was observed after immunization, which signifies both Th1- and Th2-induced immune responses. Among the vaccine candidates tested, S9, a double mutant (N23A and Y90A) and S19, a quadruple mutant (N23A, Y90A, R110A, and F177A), demonstrated complete protection against a lethal SEB challenge. Altogether, our results strongly suggest that these mSEBs could be an effective recombinant SEB vaccine candidates for further/future preclinical and clinical studies.
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Barnett TC, Cole JN, Rivera-Hernandez T, Henningham A, Paton JC, Nizet V, Walker MJ. Streptococcal toxins: role in pathogenesis and disease. Cell Microbiol 2015; 17:1721-41. [PMID: 26433203 DOI: 10.1111/cmi.12531] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 08/13/2015] [Accepted: 09/02/2015] [Indexed: 12/15/2022]
Abstract
Group A Streptococcus (Streptococcus pyogenes), group B Streptococcus (Streptococcus agalactiae) and Streptococcus pneumoniae (pneumococcus) are host-adapted bacterial pathogens among the leading infectious causes of human morbidity and mortality. These microbes and related members of the genus Streptococcus produce an array of toxins that act against human cells or tissues, resulting in impaired immune responses and subversion of host physiological processes to benefit the invading microorganism. This toxin repertoire includes haemolysins, proteases, superantigens and other agents that ultimately enhance colonization and survival within the host and promote dissemination of the pathogen.
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Affiliation(s)
- Timothy C Barnett
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Jason N Cole
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia.,Department of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Tania Rivera-Hernandez
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Anna Henningham
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia.,Department of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - James C Paton
- Research Centre for Infectious Diseases, Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Victor Nizet
- Department of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Mark J Walker
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
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Moreland NJ, Waddington CS, Williamson DA, Sriskandan S, Smeesters PR, Proft T, Steer AC, Walker MJ, Baker EN, Baker MG, Lennon D, Dunbar R, Carapetis J, Fraser JD. Working towards a Group A Streptococcal vaccine: Report of a collaborative Trans-Tasman workshop. Vaccine 2014; 32:3713-20. [DOI: 10.1016/j.vaccine.2014.05.017] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 05/01/2014] [Indexed: 11/25/2022]
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Streptococcal superantigens: categorization and clinical associations. Trends Mol Med 2013; 20:48-62. [PMID: 24210845 DOI: 10.1016/j.molmed.2013.10.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 10/01/2013] [Accepted: 10/08/2013] [Indexed: 01/01/2023]
Abstract
Superantigens are key virulence factors in the immunopathogenesis of invasive disease caused by group A streptococcus. These protein exotoxins have also been associated with severe group C and group G streptococcal infections. A number of novel streptococcal superantigens have recently been described with some resulting confusion in their classification. In addition to clarifying the nomenclature of streptococcal superantigens and proposing guidelines for their categorization, this review summarizes the evidence supporting their involvement in various clinical diseases including acute rheumatic fever.
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Yang P, Peng X, Cui S, Shao J, Zhu X, Zhang D, Liang H, Wang Q. Development of a panel of seven duplex real-time PCR assays for detecting 13 streptococcal superantigens. Ann Clin Microbiol Antimicrob 2013; 12:18. [PMID: 23895694 PMCID: PMC3737041 DOI: 10.1186/1476-0711-12-18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 07/27/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Streptococcal superantigens (SAgs) are the major virulence factors of infection in humans for group A Streptococcus (GAS) bacteria. A panel consisting of seven duplex real-time PCR assays was developed to simultaneously detect 13 streptococcal SAgs and one internal control which may be important in the control of GAS-mediated diseases. METHODS Primer and probe sequences were selected based on the highly conserved region from an alignment of nucleotide sequences of the 13 streptococcal SAgs. The reaction conditions of the duplex real-time PCR were optimized and the specificity of the duplex assays was evaluated using SAg positive strains. The limit of detection of the duplex assays was determined by using 10-fold serial dilutions of the DNA of 13 streptococcal SAgs and compared to a conventional polymerase chain reaction (PCR) method for evaluating the duplex assays sensitivity. RESULTS Using the duplex assays, we were able to differentiate between 13 SAgs from Streptococcus strains and other non-Streptococcus bacteria without cross-reaction. On the other hand, the limit of detection of the duplex assays was at least one or two log dilutions lower than that of the conventional PCR. CONCLUSIONS The panel was highly specific (100%) and the limit of detection of these duplex groups was at least ten times lower than that obtained by using a conventional PCR method.
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Affiliation(s)
- Peng Yang
- Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control (CDC), Beijing Research Center for Preventive Medicine, Capital Medical University School of Public Health, No,16 He Pingli Middle Street, Dongcheng District, Beijing 100013, China
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Huvenne W, Hellings PW, Bachert C. Role of staphylococcal superantigens in airway disease. Int Arch Allergy Immunol 2013; 161:304-14. [PMID: 23689556 DOI: 10.1159/000350329] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Staphylococcus aureus is a common human pathogen, which is regularly part of the normal microflora found in the nose and skin. It represents a significant threat to human health, not in the least because of its capability to produce exotoxins, which have superantigenic properties. These exotoxins, in particular the staphylococcal enterotoxins (SEs), are known to be involved in the modulation and aggravation of airway inflammation. Indeed, recent studies show an important impact of SEs on the natural course of allergic rhinitis, nasal polyposis, asthma and COPD. This review outlines the current knowledge on the influence of SEs on airway inflammation. We highlight, in particular, the recent evidence on their role in asthma.
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Affiliation(s)
- Wouter Huvenne
- Upper Airways Research Laboratory, Department of Otorhinolaryngology - Head and Neck Surgery, Ghent University Hospital, Ghent, Belgium.
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11
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Friães A, Pinto FR, Silva-Costa C, Ramirez M, Melo-Cristino J. Superantigen gene complement of Streptococcus pyogenes--relationship with other typing methods and short-term stability. Eur J Clin Microbiol Infect Dis 2012; 32:115-25. [PMID: 22936424 DOI: 10.1007/s10096-012-1726-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 08/08/2012] [Indexed: 02/06/2023]
Abstract
The profiling of the superantigen (SAg) encoding genes has been frequently used as a complementary typing method for group A streptococci (GAS), but a confusing gene nomenclature and a large diversity of primers used in screening has led to some conflicting results. The aim of this work was to develop a polymerase chain reaction (PCR) method capable of efficiently amplifying all the known allelic variants of these genes, and to evaluate the congruence of this methodology with other commonly used molecular typing methods. The presence of the 11 known SAg genes and two other exotoxin-encoding genes (speB and speF) was tested in a collection of 480 clinical GAS isolates, using two multiplex PCR reactions. The SAg gene profile was compared with other typing methods. Four naturally occurring deletions involving the genes speB, speF, and rgg were characterized, two of which were found among invasive isolates. The absence of the chromosomally encoded genes speG and smeZ was supported by Southern blot hybridization and associated with specific GAS lineages, while the presence of phage-encoded genes was more variable. Positive associations between SAg genes or between SAg profiles and emm types or pulsed-field gel electrophoresis (PFGE) clusters were observed. The results suggest that the SAg profile diversifies faster than other properties commonly used for molecular typing, such as emm type and multilocus sequence typing (MLST) sequence types (STs), and can be a useful complement in GAS molecular epidemiology. Still, the short-term stability of the SAg gene profile among prevalent genetic lineages may largely explain the observed associations between SAg genes.
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Affiliation(s)
- A Friães
- Instituto de Microbiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av Prof Egas Moniz, 1649-028 Lisboa, Portugal
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Karauzum H, Chen G, Abaandou L, Mahmoudieh M, Boroun AR, Shulenin S, Devi VS, Stavale E, Warfield KL, Zeitlin L, Roy CJ, Sidhu SS, Aman MJ. Synthetic human monoclonal antibodies toward staphylococcal enterotoxin B (SEB) protective against toxic shock syndrome. J Biol Chem 2012; 287:25203-15. [PMID: 22645125 PMCID: PMC3408135 DOI: 10.1074/jbc.m112.364075] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/04/2012] [Indexed: 01/25/2023] Open
Abstract
Staphylococcal enterotoxin B (SEB) is a potent toxin that can cause toxic shock syndrome and act as a lethal and incapacitating agent when used as a bioweapon. There are currently no vaccines or immunotherapeutics available against this toxin. Using phage display technology, human antigen-binding fragments (Fabs) were selected against SEB, and proteins were produced in Escherichia coli cells and characterized for their binding affinity and their toxin neutralizing activity in vitro and in vivo. Highly protective Fabs were converted into full-length IgGs and produced in mammalian cells. Additionally, the production of anti-SEB antibodies was explored in the Nicotiana benthamiana plant expression system. Affinity maturation was performed to produce optimized lead anti-SEB antibody candidates with subnanomolar affinities. IgGs produced in N. benthamiana showed characteristics comparable with those of counterparts produced in mammalian cells. IgGs were tested for their therapeutic efficacy in the mouse toxic shock model using different challenge doses of SEB and a treatment with 200 μg of IgGs 1 h after SEB challenge. The lead candidates displayed full protection from lethal challenge over a wide range of SEB challenge doses. Furthermore, mice that were treated with anti-SEB IgG had significantly lower IFNγ and IL-2 levels in serum compared with mock-treated mice. In summary, these anti-SEB monoclonal antibodies represent excellent therapeutic candidates for further preclinical and clinical development.
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Affiliation(s)
- Hatice Karauzum
- From Integrated Biotherapeutics, Inc., Gaithersburg, Maryland 20878
| | - Gang Chen
- the Banting and Best Department of Medical Research, Department of Molecular Genetics, and the Terrence Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Laura Abaandou
- From Integrated Biotherapeutics, Inc., Gaithersburg, Maryland 20878
| | - Mahta Mahmoudieh
- From Integrated Biotherapeutics, Inc., Gaithersburg, Maryland 20878
| | - Atefeh R. Boroun
- From Integrated Biotherapeutics, Inc., Gaithersburg, Maryland 20878
| | - Sergey Shulenin
- From Integrated Biotherapeutics, Inc., Gaithersburg, Maryland 20878
| | - V. Sathya Devi
- From Integrated Biotherapeutics, Inc., Gaithersburg, Maryland 20878
| | - Eric Stavale
- From Integrated Biotherapeutics, Inc., Gaithersburg, Maryland 20878
| | | | - Larry Zeitlin
- Mapp Biopharmaceutical, San Diego, California 92121, and
| | - Chad J. Roy
- the Tulane National Primate Research Center, Tulane School of Medicine, Covington, Louisiana 70433
| | - Sachdev S. Sidhu
- the Banting and Best Department of Medical Research, Department of Molecular Genetics, and the Terrence Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - M. Javad Aman
- From Integrated Biotherapeutics, Inc., Gaithersburg, Maryland 20878
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Abstract
Superantigens (SAgs) are derived from diverse sources, including bacteria, viruses, and human hepatic tissue. SAgs initially cause lymphocyte activation but then result in clonal deletion and anergy, leading to immune tolerance. They can also act as superallergens by stimulating a broad spectrum of mast cells and basophils in patients with allergic conditions. The newly described staphylococcal SAg-like proteins subvert innate immune function by several mechanisms, which are distinct from SAgs' effects on lymphocytes and other acquired immune processes. There is mounting evidence to suggest that SAgs play a role in the pathophysiology of inflammatory airway disease. The pathophysiologic role of SAg-like proteins awaits clarification.
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Affiliation(s)
- Nicholas W Stow
- Department of Otorhinolaryngology-Head and Neck Surgery, North Shore Hospital, Private Bag 93-503 Takapuna, North Shore City 0740, Auckland, New Zealand.
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Group A Streptococcus virulence and host factors in two toddlers with rheumatic fever following toxic shock syndrome. Int J Infect Dis 2010; 14:e403-9. [DOI: 10.1016/j.ijid.2009.06.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 06/17/2009] [Accepted: 06/20/2009] [Indexed: 11/20/2022] Open
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Abstract
Toxic shock syndrome (TSS) is an acute, multi-system, toxin-mediated illness, often resulting in multi-organ failure. It represents the most fulminant expression of a spectrum of diseases caused by toxin-producing strains of Staphylococcus aureus and Streptococcus pyogenes (group A streptococcus). The importance of Gram-positive organisms as pathogens is increasing, and TSS is likely to be underdiagnosed in patients with staphylococcal or group A streptococcal infection who present with shock. TSS results from the ability of bacterial toxins to act as superantigens, stimulating immune-cell expansion and rampant cytokine expression in a manner that bypasses normal MHC-restricted antigen processing. A repetitive cycle of cell stimulation and cytokine release results in a cytokine avalanche that causes tissue damage, disseminated intravascular coagulation, and organ dysfunction. Specific therapy focuses on early identification of the illness, source control, and administration on antimicrobial agents including drugs capable of suppressing toxin production (eg, clindamycin, linezolid). Intravenous immunoglobulin has the potential to neutralise superantigen and to mitigate subsequent tissue damage.
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Streptococcal Infections. BACTERIAL INFECTIONS OF HUMANS 2009. [PMCID: PMC7121349 DOI: 10.1007/978-0-387-09843-2_35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
The streptococci are a large heterogeneous group of gram-positive spherically shaped bacteria widely distributed in nature. They include some of the most important agents of human disease as well as members of the normal human flora. Some streptococci have been associated mainly with disease in animals, while others have been domesticated and used for the culture of buttermilk, yogurt, and certain cheeses. Those known to cause human disease comprise two broad categories: First are the pyogenic streptococci, including the familiar β-hemolytic streptococci and the pneumococcus. These organisms are not generally part of the normal flora but cause acute, often severe, infections in normal hosts. Second are the more diverse enteric and oral streptococci, which are nearly always part of the normal flora and which are more frequently associated with opportunistic infections.
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17
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Microbial recognition of human cell surface glycoconjugates. Curr Opin Struct Biol 2008; 18:567-76. [PMID: 18809496 DOI: 10.1016/j.sbi.2008.08.001] [Citation(s) in RCA: 223] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Revised: 08/05/2008] [Accepted: 08/18/2008] [Indexed: 11/20/2022]
Abstract
Infection by pathogens is generally initiated by the specific recognition of host epithelia surfaces and subsequent adhesion is essential for invasion. In their infection strategy, microorganisms often use sugar-binding proteins, that is lectins and adhesins, to recognize and bind to host glycoconjugates where sialylated and fucosylated oligosaccharides are the major targets. The lectin/glycoconjugate interactions are characterized by their high specificity and most of the time by multivalency to generate higher affinity of binding. Recent crystal structures of viral, bacterial, and parasite receptors in complex with human histo-blood group epitopes or sialylated derivatives reveal new folds and novel sugar-binding modes. They illustrate the tight specificity between tissue glycosylation and lectins.
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18
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Maripuu L, Eriksson A, Norgren M. Superantigen gene profile diversity among clinical group A streptococcal isolates. ACTA ACUST UNITED AC 2008; 54:236-44. [PMID: 18754783 DOI: 10.1111/j.1574-695x.2008.00469.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This study examines the diversity of superantigen gene profiles between and within emm-genotypes of 92 clinical group A streptococcal isolates (30 STSS, 24 sepsis, 25 erysipelas, and 12 tonsillitis) collected in Sweden between 1986 and 2001. The emm-genotype and the distribution of smeZ, speG, speJ, speA, speC, speH, speI, speK/L, speL/M, speM, and ssa genes, and the smeZ allelic variant were determined using PCR and DNA sequencing. Forty-five emm1 isolates revealed 10 superantigen gene profiles. One profile dominated and was identified in 22 isolates collected over 14 years. The results indicate that a selective advantage maintained this genotype in circulation. The superantigen content among the emm1 isolates ranged from three to seven, with smeZ-1, speG, and speA present in all but one profile. The 47 isolates of 27 other emm-genotypes exhibited 29 superantigen gene profiles. Thus, the distribution of superantigen genes was highly variable within isolates regardless of emm-genotype. Two novel emm1 subtypes and 14 novel smeZ allelic variants were identified. The 22 smeZ alleles were generally linked to the emm-genotype. The results of the investigation show that superantigen gene profiling is useful for tracking spread of clones in the community.
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Affiliation(s)
- Linda Maripuu
- Biomedical Laboratory Science, Department of Clinical Microbiology, Umeå University, Umeå, Sweden.
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Saarinen S, Kato H, Uchiyama T, Miyoshi-Akiyama T, Papageorgiou AC. Crystal Structure of Streptococcus dysgalactiae-Derived Mitogen Reveals a Zinc-Binding Site and Alterations in TcR Binding. J Mol Biol 2007; 373:1089-97. [PMID: 17900619 DOI: 10.1016/j.jmb.2007.08.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Revised: 08/13/2007] [Accepted: 08/14/2007] [Indexed: 11/25/2022]
Abstract
Bacterial superantigens are protein toxins with an ability to cause serious diseases in humans by activating a large number of T cells. Streptococcus dysgalactiae-derived mitogen (SDM) is a novel superantigen that is distinct from other known superantigens based on phylogenetic analysis. The X-ray structure of SDM has been determined at 1.95 A resolution. SDM shares the same characteristic fold with other superantigens, but it shows a major structural difference due to the lack of the alpha5 helix between the beta10 and beta11 strands. A bound zinc ion was identified in the structure at the C-terminal domain of the molecule. SDM appears to bind to the major histocompatibility complex class II beta-chain through the zinc-binding site, as described by mutagenesis data and structural comparisons. T-cell binding instead shows a significant difference compared to other superantigens. The mutation of Asn11 (a conserved residue that is known to be significant for T-cell-receptor binding in other superantigens) and Lys15 to Ala did not cause any decrease in the mitogenic activity of SDM. This observation and the lack of the alpha5 helix suggest alterations in T-cell-receptor binding.
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Affiliation(s)
- Susanna Saarinen
- Turku Center for Biotechnology, University of Turku and Abo Akademi University, PO Box 123, Tykistökatu 6, BioCity, Turku 20521, Finland
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