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Baek SH, Joung O, Lee HY, Shin JC, Choi WS, Lee TH, Hwang JS, Nam SH, Son HU, Lee SH. Anti-oxidative Fraction of Lycorma delicatula Alleviates Inflammatory Indicators. Nat Prod Commun 2018. [DOI: 10.1177/1934578x1801300413] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Lycorma delicatula is a reluctant pest capable of living in the stems of several tree species. The population has recently expanded in Korea due to several environmental factors including climate change. However, the precise reasons for this rapid and drastic increase in population size remain unknown. In order to examine the potential utility of this surplus biomass of Lycorma delicatula, we prepared an aqueous fraction from a dried imago, and tested its various anti-inflammatory activities and effects on cytokine levels in lipopolysaccharide (LPS)-activated RAW264.7 cells. The aqueous extract of Lycorma delicatula showed potent inhibitory activity on nitric oxide production, by more than 60% at a concentration of 300 μg/mL. We also evaluated interleukin (IL)-13 level using enzyme-linked immunosorbent assays (ELISAs). The anti-oxidative fraction of Lycorma delicatula inhibited LPS-induced IL-13 production in a dose-dependent manner, and T-bet promoter activity of cells treated with 300 μg/mL of Lycorma delicatula extract was also dramatically inhibited to 62% of that of LPS-treated cells. Furthermore, we compared matrix metalloproteinase-7 (MMP-7), -9, -14 and -17 expressions using reverse transcription-polymerase chain reaction (RT-PCR), which showed a drastic decrease in RNA levels in cells treated with the anti-oxidative fraction. Together, the present results suggest that the aqueous fraction of Lycorma delicatula has potential to ameliorate inflammatory characteristics during an inflammation event, supporting the idea that the fraction may be applied as a biomaterial to prevent inflammatory damage in skin tissues.
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Affiliation(s)
- Seung-Hwa Baek
- School of Food Science & Biotechnology, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Okjin Joung
- New & New Co., Ltd., Cheonan 31094, Republic of Korea
| | - Ho-Young Lee
- New & New Co., Ltd., Cheonan 31094, Republic of Korea
| | | | - Won-Sik Choi
- JeonJinBio Co., Ltd., Daegu 42716, Republic of Korea
| | - Tae Hun Lee
- JeonJinBio Co., Ltd., Daegu 42716, Republic of Korea
| | - Jae-Sam Hwang
- Department of Agricultural Biology, National Academy of Agricultural Science, RDA, Jeon-ju 54875, Republic of Korea
| | - Sung-Hee Nam
- Department of Agricultural Biology, National Academy of Agricultural Science, RDA, Jeon-ju 54875, Republic of Korea
| | - Hyeong-U Son
- School of Food Science & Biotechnology, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Sang-Han Lee
- School of Food Science & Biotechnology, Kyungpook National University, Daegu 41566, Republic of Korea
- Food & Bio-Industry Research Institute, Kyungpook National University, Daegu 41566, Republic of Korea
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2
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Alaoui H, Belhadj A, Aissaoui Y, Seddiki R, Zoubir M, Bougalem M. [Staphylococcal toxic shock syndrome at a chronic hemodialysis]. Pan Afr Med J 2017; 27:230. [PMID: 28979632 PMCID: PMC5622844 DOI: 10.11604/pamj.2017.27.230.12737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 05/18/2017] [Indexed: 11/19/2022] Open
Abstract
Le syndrome de choc toxique staphylococcique est un syndrome infectieux aigu et systémique lié à l'activité super-antigénique des toxines staphylococciques. C'est une pathologie qui est assez rare mais reste grevée d'une mortalité considérable malgré la prise en charge thérapeutique. La porte d'entrée est le plus souvent cutanée avec dissémination bactériémique secondaire pourrait être sujet de mesures préventives. Nous rapportons le cas d'un choc toxique à staphylocoque doré d'évolution rapidement mortelle, développé chez un hémodialysé chronique dont la porte d'entrée à partir de la fistule artério-veineuse était soupçonnée.
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Affiliation(s)
- Hassan Alaoui
- Pole d'Anesthésie-Réanimation, Hôpital Militaire Avicenne, Faculté de Médecine 40000 Marrakech, Maroc
| | - Ayoub Belhadj
- Pole d'Anesthésie-Réanimation, Hôpital Militaire Avicenne, Faculté de Médecine 40000 Marrakech, Maroc
| | - Younes Aissaoui
- Pole d'Anesthésie-Réanimation, Hôpital Militaire Avicenne, Faculté de Médecine 40000 Marrakech, Maroc
| | - Rachid Seddiki
- Pole d'Anesthésie-Réanimation, Hôpital Militaire Avicenne, Faculté de Médecine 40000 Marrakech, Maroc
| | - Mohamed Zoubir
- Pole d'Anesthésie-Réanimation, Hôpital Militaire Avicenne, Faculté de Médecine 40000 Marrakech, Maroc
| | - Mohamed Bougalem
- Pole d'Anesthésie-Réanimation, Hôpital Militaire Avicenne, Faculté de Médecine 40000 Marrakech, Maroc
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3
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[Staphylococcal toxic shock syndrome after breast surgery]. ACTA ACUST UNITED AC 2014; 43:526-9. [PMID: 24636869 DOI: 10.1016/j.jgyn.2014.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Revised: 01/27/2014] [Accepted: 02/06/2014] [Indexed: 11/23/2022]
Abstract
The surgical site infection occurs within 30 days after surgery. It is the most common complication of surgery, with a rate of 1 to 5% without antibiotic prophylaxis and less than 1% with antibiotic prophylaxis. The toxic shock syndrome (TSS) is a dramatic complication. We report the case 39-year-old woman who presented a life-threatening TSS acquired after breast surgery. We describe the signs and symptoms of this condition as well as treatment principles.
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Gui Z, Wang H, Ding T, Zhu W, Zhuang X, Chu W. Azithromycin Reduces the Production of α-hemolysin and Biofilm Formation in Staphylococcus aureus. Indian J Microbiol 2013; 54:114-7. [PMID: 24426177 DOI: 10.1007/s12088-013-0438-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 11/09/2013] [Indexed: 11/26/2022] Open
Abstract
Staphylococcus aureus causes a broad range of life-threatening diseases in humans. This bacterium produces a large number of extracellular virulence factors that are closely associated with specific diseases which are controlled by quorum sensing. In this study, we show that azithromycin was active against methicillin-resistant Staphylococcus aureus (MRSA) strains with MICs ranged from 32 to 64 μg/mL. Azithromycin at subinhibitory concentration, markedly reduced the production of α-hemolysin at (1/16MIC, 1/8MIC) and biofilm formation at (1/16MIC, 1/8MIC), respectively. The results indicated that sub-inhibitory concentrations of azithromycin decreased the production of α-hemolysin and biofilm formation in MRSA in a dose-dependent manner. Therefore, azithromycin may be useful in the treatment of α-hemolysin producing and biofilm formation MRSA infections.
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Affiliation(s)
- Zhihong Gui
- Lishui People's Hospital, Lishui, 323000 China
| | - Huafu Wang
- Lishui People's Hospital, Lishui, 323000 China
| | - Ting Ding
- Lishui People's Hospital, Lishui, 323000 China
| | - Wei Zhu
- Department of Microbiology, School of Life Science and Technology, China Pharmaceutical University, Nanjing, 210009 China
| | - Xiyi Zhuang
- Department of Microbiology, School of Life Science and Technology, China Pharmaceutical University, Nanjing, 210009 China
| | - Weihua Chu
- Department of Microbiology, School of Life Science and Technology, China Pharmaceutical University, Nanjing, 210009 China
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5
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Targeting the host–pathogen interface for treatment of Staphylococcus aureus infection. Semin Immunopathol 2011; 34:299-315. [DOI: 10.1007/s00281-011-0297-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 10/17/2011] [Indexed: 12/15/2022]
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6
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Tidswell M, LaRosa SP. Toll-like receptor-4 antagonist eritoran tetrasodium for severe sepsis. Expert Rev Anti Infect Ther 2011; 9:507-20. [PMID: 21609262 DOI: 10.1586/eri.11.27] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The human innate immune system initiates inflammation in response to bacterial molecules, particularly Gram-negative bacterial endotoxin. The steps by which endotoxin exposure leads to systemic inflammation include binding to Toll-like receptor-4 that specifically recognizes endotoxin and subsequently triggers cellular and molecular inflammatory responses. Severe sepsis is a systemic inflammatory response to infection that induces organ dysfunction and threatens a person's survival. Severe sepsis is frequently associated with increased blood levels of endotoxin. It is a significant medical problem that effects approximately 700,000 patients every year in the USA, resulting in 250,000 deaths. Eritoran tetrasodium is a nonpathogenic analog of bacterial endotoxin that antagonizes inflammatory signaling by the immune receptor Toll-like receptor-4. Eritoran is being evaluated for the treatment of patients with severe sepsis.
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Affiliation(s)
- Mark Tidswell
- Adult Critical Care Division, Baystate Medical Center, 759 Chestnut Street, Springfield, MA 01199, USA.
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8
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Abstract
Severe sepsis, defined as inflammation and organ failure due to infection, continues to result in a mortality of approximately 30% despite advances in critical care. Current therapy includes timely administration of antibiotics, source control of infection, aggressive fluid resuscitation, support of failing organs, and use of activated protein C where clinically indicated. Bacterial mediators, including endotoxin and superantigens, as well endogenous proinflammatory cytokines are considered important to the pathogenesis of sepsis-induced organ failure and are being targeted with numerous molecules and removal devices. Additional therapeutic strategies are aimed at restoring the natural anticoagulant levels, blocking deleterious effects of the complement cascade, reversing cytopathic hypoxia, and inhibiting excessive lymphocyte apoptosis. Molecules with pluripotent activity, such as interalpha inhibitor proteins and estrogen-receptor ligands, are also being investigated.
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Affiliation(s)
- Steven P LaRosa
- Warren Alpert School of Medicine, Brown University, Providence, RI, USA.
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9
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Choc toxique staphylococcique dans un contexte menstruel de port de tampons vaginaux d’évolution favorable après optimisation hémodynamique précoce et administration de protéine C activée. ACTA ACUST UNITED AC 2009; 28:91-5. [DOI: 10.1016/j.annfar.2008.10.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Accepted: 10/30/2008] [Indexed: 11/22/2022]
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10
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Kiran MD, Adikesavan NV, Cirioni O, Giacometti A, Silvestri C, Scalise G, Ghiselli R, Saba V, Orlando F, Shoham M, Balaban N. Discovery of a quorum-sensing inhibitor of drug-resistant staphylococcal infections by structure-based virtual screening. Mol Pharmacol 2008; 73:1578-86. [PMID: 18314496 DOI: 10.1124/mol.107.044164] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Staphylococci are a major health threat because of increasing resistance to antibiotics. An alternative to antibiotic treatment is preventing virulence by inhibition of bacterial cell-to-cell communication using the quorum-sensing inhibitor RNAIII-inhibiting peptide (RIP). In this work, we identified 2',5-di-O-galloyl-d-hamamelose (hamamelitannin) as a nonpeptide analog of RIP by virtual screening of a RIP-based pharmacophore against a database of commercially available small-molecule compounds. Hamamelitannin is a natural product found in the bark of Hamamelis virginiana (witch hazel), and it has no effect on staphylococcal growth in vitro; but like RIP, it does inhibit the quorum-sensing regulator RNAIII. In a rat graft model, hamamelitannin prevented device-associated infections in vivo, including infections caused by methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis strains. These findings suggest that hamamelitannin may be used as a suppressor to staphylococcal infections.
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Affiliation(s)
- Madanahally D Kiran
- Department of Biomedical Sciences, Cummings School of Veterinary Medicine, Tufts University, 200 Westboro Rd., North Grafton, MA 01536, USA
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11
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One in five mortality in non-menstrual toxic shock syndrome versus no mortality in menstrual cases in a balanced French series of 55 cases. Eur J Clin Microbiol Infect Dis 2007; 27:37-43. [DOI: 10.1007/s10096-007-0405-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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12
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Krakauer T, Stephens J, Buckley M, Tate M. Superantigen-induced cytokine release from whole-blood cell culture as a functional measure of drug efficacy after oral dosing in nonhuman primates. Res Vet Sci 2007; 83:182-7. [PMID: 17412377 DOI: 10.1016/j.rvsc.2006.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2006] [Revised: 10/03/2006] [Accepted: 12/09/2006] [Indexed: 10/23/2022]
Abstract
Evaluation of drug efficacy for human diseases is routinely performed in animal models for efficiency and in accordance with FDA regulations. Rhesus macaques have been used as models for various lethal diseases and correlates of immunity, as nonhuman primates (NHP) closely resemble humans. We examined the ex vivo cytokine response of superantigen-stimulated whole-blood cells as a first step to therapeutic efficacy testing for bacterial superantigen-induced shock in NHP after oral dosing of pentoxifylline. Doses of 120mg/kg of pentoxifylline effectively attenuated staphylococcal enterotoxin B-induced tumor necrosis factor alpha (TNFalpha), gamma interferon (IFNgamma) and interleukin 2 (IL-2) in ex vivo culture of NHP whole-blood cells by 88%, 81%, and 76%, respectively, whereas lower doses of 48 or 72mg/kg had no inhibitory effect. Thus cytokine release of stimulated peripheral blood cells provides a convenient biological measurement of the anti-inflammatory potency of pentoxifylline and has the advantage of assessing functional responses to a specific biotoxin of interest.
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Affiliation(s)
- Teresa Krakauer
- Integrated Toxicology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702-5011, USA.
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13
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Krakauer T, Buckley M. Dexamethasone attenuates staphylococcal enterotoxin B-induced hypothermic response and protects mice from superantigen-induced toxic shock. Antimicrob Agents Chemother 2006; 50:391-5. [PMID: 16377721 PMCID: PMC1346818 DOI: 10.1128/aac.50.1.391-395.2006] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The superantigenic staphylococcal enterotoxins are important virulence factors and contribute to various diseases, including food poisoning and toxic shock. Dexamethasone, an anti-inflammatory agent, attenuated staphylococcal enterotoxin B (SEB)-induced hypothermia and serum proinflammatory cytokines and improved survival from 0% to 86% in a lethal mouse model of SEB-mediated shock.
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Affiliation(s)
- Teresa Krakauer
- Integrated Toxicology Division, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, Maryland 21702-5011, USA.
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14
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Burnett JC, Henchal EA, Schmaljohn AL, Bavari S. The evolving field of biodefence: therapeutic developments and diagnostics. Nat Rev Drug Discov 2005; 4:281-97. [PMID: 15803193 PMCID: PMC7096857 DOI: 10.1038/nrd1694] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Bioweapons are a clear threat to both military and civilian populations. Here, the latest advances in the pursuit of inhibitors against biothreat threat toxins, current therapeutic strategies for treating biodefence related pathogens, and strategies for improving detection and exposure survivability are covered. There are numerous lead therapeutics that have emerged from drug discovery efforts. However, many of these are toxic and/or fail to possess conventional drug-like properties. One clear advantage of small (non-peptidic) molecules is that they possess scaffolds that are inherently more likely to evolve into real therapeutics. One of the major obstacles impeding the translation of these lead therapeutics into viable drugs is the lack of involvement of the pharmaceutical industry, which has been discovering leads and translating them into drugs for decades. The expertise of the pharmaceutical industry therefore needs to be more effectively engaged in developing drugs against biothreat agents. New methods for rapidly detecting and diagnosing biothreat agents are also in development. The detection and diagnosis of biothreats is inherently linked with treatment. The means for detecting the release of bioweapons are being deployed, and new technologies are shortening the timeframe between initial sample collection and conclusive agent determination. However, the organization of this process is imperfect. At present, a unifying entity that orchestrates the biodefence response is clearly needed to reduce the time-to-drug process and redundancies in drug development efforts. Such a central entity could formulate and implement plans to coordinate all participants, including academic institutions, government agencies and the private sector. This could accelerate the development of countermeasures against high probability biothreat agents.
The threat of bioterrorism and the potential use of biological weapons against both military and civilian populations has become a major concern for governments around the world. For example, in 2001 anthrax-tainted letters resulted in several deaths, caused widespread public panic and exerted a heavy economic toll. If such a small-scale act of bioterrorism could have such a huge impact, then the effects of a large-scale attack would be catastrophic. This review covers recent progress in developing therapeutic countermeasures against, and diagnostics for, such agents.
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Affiliation(s)
- James C. Burnett
- Developmental Therapeutics Program, Target Structure-Based Drug Discovery Group, National Cancer Institute-SAIC, Frederick, 21702 Maryland USA
| | - Erik A. Henchal
- United States Army Medical Research Institute of Infectious Diseases, Frederick, 21702 Maryland USA
| | - Alan L. Schmaljohn
- United States Army Medical Research Institute of Infectious Diseases, Frederick, 21702 Maryland USA
| | - Sina Bavari
- United States Army Medical Research Institute of Infectious Diseases, Frederick, 21702 Maryland USA
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15
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Rajagopalan G, Sen MM, David CS. In vitro and in vivo evaluation of staphylococcal superantigen peptide antagonists. Infect Immun 2004; 72:6733-7. [PMID: 15501813 PMCID: PMC522998 DOI: 10.1128/iai.72.11.6733-6737.2004] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Superantigen peptide antagonists failed to block T-cell activation and cytokine production as well as toxic shock induced by staphylococcal enterotoxin B (SEB) in HLA class II transgenic mice. They also failed to inhibit the binding of SEB to HLA class II molecules as well as activation of human T lymphocytes in vitro.
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Affiliation(s)
- Govindarajan Rajagopalan
- Department of Immunology, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN 55905, USA
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16
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De Marzí MC, Fernández MM, Sundberg EJ, Molinero L, Zwirner NW, Llera AS, Mariuzza RA, Malchiodi EL. Cloning, expression and interaction of human T-cell receptors with the bacterial superantigen SSA. ACTA ACUST UNITED AC 2004; 271:4075-83. [PMID: 15479236 DOI: 10.1111/j.1432-1033.2004.04345.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Superantigens (SAgs) are a class of disease-causing and immunostimulatory proteins of bacterial or viral origin that activate a large number of T-cells through interaction with the Vbeta domain of T-cell receptors (TCRs). In this study, recombinant TCR beta chains were constructed with human variable domains Vbeta5.2, Vbeta1 and Vbeta2.1, expressed as inclusion bodies, refolded and purified. The Streptococcus pyogenes SAg SSA-1 was cloned and expressed as a soluble periplasmic protein. SSA-1 was obtained both as a monomer and a dimer that has an intermolecular disulfide bond. We analyzed the biological activity of the recombinant SAgs by proliferation assays. The results suggest that SSA dimerization occludes the TCR interaction site. Naturally occurring SSA dimerization was also observed in supernatants of S. pyogenes isolates. An SSA mutant [SSA(C26S)] was produced to eliminate the Cys responsible for dimerization. Affinity assays using a resonant biosensor showed that both the mutant and monomeric wild type SSA have affinity for human Vbeta5.2 and Vbeta1 with Kd of 9-11 microm with a fast kass and a moderately fast kdiss. In spite of the reported stimulation of Vbeta2.1 bearing T-cells by SSA, we observed no measurable interaction.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigens, Bacterial/chemistry
- Antigens, Bacterial/immunology
- Antigens, Bacterial/metabolism
- Cloning, Molecular
- Dimerization
- Dose-Response Relationship, Immunologic
- Electrophoresis, Polyacrylamide Gel
- Gene Expression
- Humans
- Immunoblotting
- Lymphocyte Activation
- Mice
- Models, Molecular
- Molecular Sequence Data
- Protein Binding
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- Recombinant Proteins/metabolism
- Streptococcus pyogenes/immunology
- Superantigens/chemistry
- Superantigens/immunology
- Superantigens/metabolism
- Superantigens/pharmacology
- T-Lymphocytes/cytology
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
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Affiliation(s)
- Mauricio C De Marzí
- Cátedra de Inmunología and Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
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17
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Gov Y, Borovok I, Korem M, Singh VK, Jayaswal RK, Wilkinson BJ, Rich SM, Balaban N. Quorum Sensing in Staphylococci Is Regulated via Phosphorylation of Three Conserved Histidine Residues. J Biol Chem 2004; 279:14665-72. [PMID: 14726534 DOI: 10.1074/jbc.m311106200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Staphylococcus aureus cause infections by producing toxins, a process regulated by cell-cell communication (quorum sensing) through the histidine-phosphorylation of the target of RNAIII-activating protein (TRAP). We show here that TRAP is highly conserved in staphylococci and contains three completely conserved histidine residues (His-66, His-79, His-154) that are phosphorylated and essential for its activity. This was tested by constructing a TRAP(-) strain with each of the conserved histidine residues changed to alanine by site-directed mutagenesis. All mutants were tested for pathogenesis in vitro (expression of RNAIII and hemolytic activity) and in vivo (murine cellulitis model). Results show that RNAIII is not expressed in the TRAP(-) strain, that it is non hemolytic, and that it does not cause disease in vivo. These pathogenic phenotypes could be rescued in the strain containing the recovered traP, confirming the importance of TRAP in S. aureus pathogenesis. The phosphorylation of TRAP mutated in any of the conserved histidine residues was significantly reduced, and mutants defective in any one of these residues were non-pathogenic in vitro or in vivo, whereas those mutated in a non-conserved histidine residue (His-124) were as pathogenic as the wild type. These results confirm the importance of the three conserved histidine residues in TRAP activity. The phosphorylation pattern, structure, and gene organization of TRAP deviates from signaling molecules known to date, suggesting that TRAP belongs to a novel class of signal transducers.
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Affiliation(s)
- Yael Gov
- Department of Human Microbiology, Sackler School of Medicine, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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18
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Hong-Geller E, Möllhoff M, Shiflett PR, Gupta G. Design of Chimeric Receptor Mimics with Different TcRVβ Isoforms. J Biol Chem 2004; 279:5676-84. [PMID: 14604991 DOI: 10.1074/jbc.m309388200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Staphylococcus aureus enterotoxins (S.E.) A-I, and toxic-shock syndrome toxin TSST-1 act as superantigens to cause overstimulation of the host immune system, leading to the onset of various diseases including food poisoning and toxic shock syndrome. SAgs bind as intact proteins to the DRalpha1 domain of the MHC class II receptor and the TcRVbeta domain from the T cell receptor and cause excessive release of cytokines such as IL-2, TNF-alpha, and IFN-gamma, and hyperproliferation of T cells. In addition, different SAgs bind and activate different TcRVbeta isoforms during pathogenesis of human immune cells. These two properties of SAgs prompted us to design several chimeric DRalpha1-linker-TcRVbeta proteins using different TcRVbeta isoforms to create chimeras that would specifically inhibit the pathogenesis of SAgs against which they were designed. In this study, we compare the design, interaction, and inhibitory properties of three different DRalpha1-linker-TcRVbeta chimeras targeted against three different SAgs, SEB, SEC3, and TSST-1. The inhibitory properties of the chimeras were tested by monitoring IL-2 release and T cell proliferation using a primary human cell model. We demonstrate that the three chimeras specifically inhibit the pathogenesis of their target superantigen. We performed molecular modeling to analyze the structural basis of the type specificity exhibited by different chimeras designed against their target SAgs, examine the role of the linker in determining binding and specificity, and suggest site-specific mutations in the chimera to enhance binding affinity. The fact that our strategy works equally well for SEB and TSST-1, two widely different phylogenic variants, suggests that the DRalpha1-linker-TcRVbeta chimeras may be developed as a general therapy against a broad spectrum of superantigens released during Staphylococcal infection.
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MESH Headings
- Amino Acid Sequence
- Antigens/chemistry
- Cell Division
- Cell Line
- Cloning, Molecular
- Enterotoxins/chemistry
- Humans
- Interleukin-2/metabolism
- Kinetics
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Protein Binding
- Protein Isoforms
- Protein Structure, Tertiary
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/physiology
- Recombinant Fusion Proteins/metabolism
- Sequence Homology, Amino Acid
- Staphylococcus aureus/metabolism
- T-Lymphocytes/metabolism
- Temperature
- Time Factors
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Affiliation(s)
- Elizabeth Hong-Geller
- Los Alamos National Laboratory, Biosciences Division, HRL-1, MS-M888, Los Alamos, New Mexico 87544, USA
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19
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Degl'Innocenti D, Taddei N, Ramazzotti M, Stefani M, Chiti F, Ramponi G. Selection of antibody fragments specific for an alpha-helix region of acylphosphatase. J Mol Recognit 2004; 17:62-6. [PMID: 14872538 DOI: 10.1002/jmr.653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The native state of common-type acylphosphatase (AcP) elicits two alpha-helices spanning residues 22-32 and 55-67 in the protein sequence. A peptide corresponding to the second alpha-helix (helix-2) of the protein was used to select phage antibodies consisting of a single chain fragment variable. The selection was performed in the presence of trifluoroethanol, a cosolvent known to induce the formation of helical structure in peptides and proteins. Phage scFv antibodies capable of binding the peptide specifically in a trifluoroethanol-induced alpha-helical conformation were isolated by affinity selection (biopanning). Some of these scFvs were also able to bind the native protein but not the peptide in a non-helical unstructured state. This indicates that the structural determinant recognized by the selected antibodies is the alpha-helical conformation of this specific region, rather than simply its amino acid sequence. This study shows that phage display libraries can be used to raise antibodies one can use as reagents able to target regions of a protein with a specific native-like secondary structure.
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Affiliation(s)
- Donatella Degl'Innocenti
- Dipartimento di Scienze Biochimiche, Università degli Studi di Firenze, Viale Morgagni 50, Firenze 50134, Italy.
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