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Wang P, Fredj Z, Zhang H, Rong G, Bian S, Sawan M. Blocking Superantigen-Mediated Diseases: Challenges and Future Trends. J Immunol Res 2024; 2024:2313062. [PMID: 38268531 PMCID: PMC10807946 DOI: 10.1155/2024/2313062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/15/2023] [Accepted: 12/30/2023] [Indexed: 01/26/2024] Open
Abstract
Superantigens are virulence factors secreted by microorganisms that can cause various immune diseases, such as overactivating the immune system, resulting in cytokine storms, rheumatoid arthritis, and multiple sclerosis. Some studies have demonstrated that superantigens do not require intracellular processing and instated bind as intact proteins to the antigen-binding groove of major histocompatibility complex II on antigen-presenting cells, resulting in the activation of T cells with different T-cell receptor Vβ and subsequent overstimulation. To combat superantigen-mediated diseases, researchers have employed different approaches, such as antibodies and simulated peptides. However, due to the complex nature of superantigens, these approaches have not been entirely successful in achieving optimal therapeutic outcomes. CD28 interacts with members of the B7 molecule family to activate T cells. Its mimicking peptide has been suggested as a potential candidate to block superantigens, but it can lead to reduced T-cell activity while increasing the host's infection risk. Thus, this review focuses on the use of drug delivery methods to accurately target and block superantigens, while reducing the adverse effects associated with CD28 mimic peptides. We believe that this method has the potential to provide an effective and safe therapeutic strategy for superantigen-mediated diseases.
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Affiliation(s)
- Pengbo Wang
- CenBRAIN Neurotech, School of Engineering, Westlake University, Hangzhou 310030, China
| | - Zina Fredj
- CenBRAIN Neurotech, School of Engineering, Westlake University, Hangzhou 310030, China
| | - Hongyong Zhang
- CenBRAIN Neurotech, School of Engineering, Westlake University, Hangzhou 310030, China
| | - Guoguang Rong
- CenBRAIN Neurotech, School of Engineering, Westlake University, Hangzhou 310030, China
| | - Sumin Bian
- CenBRAIN Neurotech, School of Engineering, Westlake University, Hangzhou 310030, China
| | - Mohamad Sawan
- CenBRAIN Neurotech, School of Engineering, Westlake University, Hangzhou 310030, China
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Knopick P, Terman D, Riha N, Alvine T, Larson R, Badiou C, Lina G, Ballantyne J, Bradley D. Endogenous HLA-DQ8αβ programs superantigens (SEG/SEI) to silence toxicity and unleash a tumoricidal network with long-term melanoma survival. J Immunother Cancer 2021; 8:jitc-2020-001493. [PMID: 33109631 PMCID: PMC7592263 DOI: 10.1136/jitc-2020-001493] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/10/2020] [Indexed: 12/17/2022] Open
Abstract
Background As the most powerful T cell agonists known, superantigens (SAgs) have enormous potential for cancer immunotherapy. Their development has languished due to high incidence (60%–80%) of seroreactive neutralizing antibodies in humans and tumor necrosis factor-α (TNFα)-mediated cardiopulmonary toxicity. Such toxicity has narrowed their therapeutic index while neutralizing antibodies have nullified their therapeutic effects. Methods Female HLA-DQ8 (DQA*0301/DQB*0302) tg mice expressing the human major histocompatibility complex II (MHCII) HLA-DQ8 allele on a high proportion of PBL, spleen and lymph node cells were used. In the established tumor model, staphylococcal enterotoxin G and staphylococcal enterotoxin I (SEG/ SEI) (50 µg each) were injected on days 6 and 9 following tumor inoculation. Lymphoid, myeloid cells and tumor cell digests from tumor tissue were assayed using flow cytometry or quantitated using a cytometric bead array. Tumor density, necrotic and viable areas were quantitated using the ImageJ software. Results In a discovery-driven effort to address these problems we introduce a heretofore unrecognized binary complex comprizing SEG/SEI SAgs linked to the endogenous human MHCII HLA-DQ8 allele in humanized mice. By contrast to staphylococcal enterotoxin A (SEA) and staphylococcal enterotoxin B (SEB) deployed previously in clinical trials, SEG and SEI does not exhibit neutralizing antibodies in humans or TNFα-mediated toxicity in humanized HLA-DQ8 mice. In the latter model wherein SAg behavior is known to be ‘human-like’, SEG/SEI induced a powerful tumoricidal response and long-term survival against established melanoma in 82% of mice. Other SAgs deployed in the same model displayed toxic shock. Initially, HLA-DQ8 mediated melanoma antigen priming, after which SEG/SEI unleashed a broad CD4+ and CD8+ antitumor network marked by expansion of melanoma reactive T cells and interferon-γ (IFNy) in the tumor microenvironment (TME). SEG/SEI further initiated chemotactic recruitment of tumor reactive T cells to the TME converting the tumor from ‘cold’ to a ‘hot’. Long-term survivors displayed remarkable resistance to parental tumor rechallenge along with the appearance of tumor specific memory and tumor reactive T memory cells. Conclusions Collectively, these findings show for the first time that the SEG/SEI-(HLA-DQ8) empowers priming, expansion and recruitment of a population of tumor reactive T cells culminating in tumor specific memory and long-term survival devoid of toxicity. These properties distinguish SEG/SEI from other SAgs used previously in human tumor immunotherapy. Consolidation of these principles within the SEG/SEI-(HLA-DQ8) complex constitutes a conceptually new therapeutic weapon with compelling translational potential.
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Affiliation(s)
- Peter Knopick
- Biomedical Sciences, Universtiy of North Dakota School of Medicine, Grand Forks, North Dakota, USA
| | - David Terman
- Biomedical Sciences, Universtiy of North Dakota School of Medicine, Grand Forks, North Dakota, USA
| | - Nathan Riha
- Biomedical Sciences, Universtiy of North Dakota School of Medicine, Grand Forks, North Dakota, USA
| | - Travis Alvine
- Biomedical Sciences, Universtiy of North Dakota School of Medicine, Grand Forks, North Dakota, USA
| | - Riley Larson
- Biomedical Sciences, Universtiy of North Dakota School of Medicine, Grand Forks, North Dakota, USA
| | - Cedric Badiou
- University of Lyon, Lyon, Auvergne-Rhône-Alpes, France
| | - Gerard Lina
- University of Lyon 1 University Institute of Tecnology Lyon 1, Villeurbanne, Auvergne-Rhône-Alpes, France
| | | | - David Bradley
- Biomedical Sciences, Universtiy of North Dakota School of Medicine, Grand Forks, North Dakota, USA
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Hu N, Qiao C, Wang J, Wang Z, Li X, Zhou L, Wu J, Zhang D, Feng J, Shen B, Zhang J, Luo L. Identification of a novel protective human monoclonal antibody, LXY8, that targets the key neutralizing epitopes of staphylococcal enterotoxin B. Biochem Biophys Res Commun 2021; 549:120-127. [PMID: 33667709 DOI: 10.1016/j.bbrc.2021.02.057] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Accepted: 02/14/2021] [Indexed: 10/22/2022]
Abstract
Staphylococcal enterotoxin B (SEB), one of the exotoxins produced by Staphylococcus aureus, is the key toxin that causes poisoning reactions and toxic shock syndrome. In the current research work, a novel human antibody named LXY8 was screened from a human phage display antibody library, and LXY8 blocked the interaction between SEB and the T cell receptor (TCR). The binding activity between LXY8 and SEB was 0.525 nM. Furthermore, LXY8 could effectively inhibit the SEB-induced activation of peripheral blood mononuclear cells and release of cytokines. In the BALB/c mouse model, LXY8 effectively neutralized SEB toxicity in vivo. Finally, based on computer-guided molecular modeling, we designed a series of SEB mutation sites; these sites facilitated the determination of the key residues (i.e.176EFNN179) of SEB recognized by LXY8. The research revealed that the 176EFNN179 residues of SEB are important for specific antibody-antigen recognition. The results may be helpful for the development of antibody-based therapy for SEB-induced toxic shock syndrome.
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Affiliation(s)
- Naijing Hu
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing, 100850, China; School of Medical Devices, Shenyang Pharmaceutical University, Shenyang, 117004, China.
| | - Chunxia Qiao
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing, 100850, China.
| | - Jing Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing, 100850, China.
| | - Zhihong Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing, 100850, China.
| | - Xinying Li
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing, 100850, China.
| | - Liuzhong Zhou
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing, 100850, China.
| | - Jiaguo Wu
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing, 100850, China.
| | - Dingmu Zhang
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing, 100850, China.
| | - Jiannan Feng
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing, 100850, China.
| | - Beifen Shen
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing, 100850, China.
| | - Jinghai Zhang
- School of Medical Devices, Shenyang Pharmaceutical University, Shenyang, 117004, China.
| | - Longlong Luo
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing, 100850, China.
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Popugailo A, Rotfogel Z, Supper E, Hillman D, Kaempfer R. Staphylococcal and Streptococcal Superantigens Trigger B7/CD28 Costimulatory Receptor Engagement to Hyperinduce Inflammatory Cytokines. Front Immunol 2019; 10:942. [PMID: 31114583 PMCID: PMC6503043 DOI: 10.3389/fimmu.2019.00942] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 04/12/2019] [Indexed: 11/13/2022] Open
Abstract
Staphylococcal and streptococcal superantigens are virulence factors that cause toxic shock by hyperinducing inflammatory cytokines. Effective T-cell activation requires interaction between the principal costimulatory receptor CD28 and its two coligands, B7-1 (CD80) and B7-2 (CD86). To elicit an inflammatory cytokine storm, bacterial superantigens must bind directly into the homodimer interfaces of CD28 and B7-2. Recent evidence revealed that by engaging CD28 and B7-2 directly at their dimer interface, staphylococcal enterotoxin B (SEB) potently enhances intercellular synapse formation mediated by B7-2 and CD28, resulting in T-cell hyperactivation. Here, we addressed the question, whether diverse bacterial superantigens share the property of triggering B7-2/CD28 receptor engagement and if so, whether they are capable of enhancing also the interaction between B7-1 and CD28, which occurs with an order-of-magnitude higher affinity. To this end, we compared the ability of distinct staphylococcal and streptococcal superantigens to enhance intercellular B7-2/CD28 engagement. Each of these diverse superantigens promoted B7-2/CD28 engagement to a comparable extent. Moreover, they were capable of triggering the intercellular B7-1/CD28 interaction, analyzed by flow cytometry of co-cultured cell populations transfected separately to express human CD28 or B7-1. Streptococcal mitogenic exotoxin Z (SMEZ), the most potent superantigen known, was as sensitive as SEB, SEA and toxic shock syndrome toxin-1 (TSST-1) to inhibition of inflammatory cytokine induction by CD28 and B7-2 dimer interface mimetic peptides. Thus, superantigens act not only by mediating unconventional interaction between MHC-II molecule and T-cell receptor but especially, by strongly promoting engagement of CD28 by its B7-2 and B7-1 coligands, a critical immune checkpoint, forcing the principal costimulatory axis to signal excessively. Our results show that the diverse superantigens use a common mechanism to subvert the inflammatory response, strongly enhancing B7-1/CD28 and B7-2/CD28 costimulatory receptor engagement.
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Affiliation(s)
- Andrey Popugailo
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Ziv Rotfogel
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Emmanuelle Supper
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Dalia Hillman
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Raymond Kaempfer
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
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Staphylococcal Superantigens: Pyrogenic Toxins Induce Toxic Shock. Toxins (Basel) 2019; 11:toxins11030178. [PMID: 30909619 PMCID: PMC6468478 DOI: 10.3390/toxins11030178] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 03/18/2019] [Accepted: 03/20/2019] [Indexed: 01/01/2023] Open
Abstract
Staphylococcal enterotoxin B (SEB) and related superantigenic toxins produced by Staphylococcus aureus are potent activators of the immune system. These protein toxins bind to major histocompatibility complex (MHC) class II molecules and specific Vβ regions of T-cell receptors (TCRs), resulting in the activation of both monocytes/macrophages and T lymphocytes. The bridging of TCRs with MHC class II molecules by superantigens triggers an early “cytokine storm” and massive polyclonal T-cell proliferation. Proinflammatory cytokines, tumor necrosis factor α, interleukin 1 (IL-1), IL-2, interferon γ (IFNγ), and macrophage chemoattractant protein 1 elicit fever, inflammation, multiple organ injury, hypotension, and lethal shock. Upon MHC/TCR ligation, superantigens induce signaling pathways, including mitogen-activated protein kinase cascades and cytokine receptor signaling, which results in NFκB activation and the phosphoinositide 3-kinase/mammalian target of rapamycin pathways. In addition, gene profiling studies have revealed the essential roles of innate antimicrobial defense genes in the pathogenesis of SEB. The genes expressed in a murine model of SEB-induced shock include intracellular DNA/RNA sensors, apoptosis/DNA damage-related molecules, endoplasmic reticulum/mitochondrial stress responses, immunoproteasome components, and IFN-stimulated genes. This review focuses on the signaling pathways induced by superantigens that lead to the activation of inflammation and damage response genes. The induction of these damage response genes provides evidence that SEB induces danger signals in host cells, resulting in multiorgan injury and toxic shock. Therapeutics targeting both host inflammatory and cell death pathways can potentially mitigate the toxic effects of staphylococcal superantigens.
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Shir A, Klein S, Sagiv-Barfi I, Geiger T, Zigler M, Langut Y, Edinger N, Levitzki A. S101, an Inhibitor of Proliferating T Cells, Rescues Mice From Superantigen-Induced Shock. J Infect Dis 2018; 217:288-297. [PMID: 29149330 DOI: 10.1093/infdis/jix576] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 11/14/2017] [Indexed: 12/16/2022] Open
Abstract
Superantigens (SAgs) are extremely potent bacterial toxins, which evoke a virulent immune response, inducing nonspecific T-cell proliferation, rapid cytokine release, and lethal toxic shock, for which there is no effective treatment. We previously developed a small molecule, S101, which potently inhibits proliferating T cells. In a severe mouse model of toxic shock, a single injection of S101 given together with superantigen challenge rescued 100% of the mice. Even when given 2 hours after challenge, S101 rescued 40% of the mice. S101 targets the T-cell receptor, inflammatory response, and actin cytoskeleton pathways. S101 inhibits the aryl hydrocarbon receptor, a ligand-activated transcription factor that is involved in the differentiation of T-helper cells, especially Th17, and regulatory T cells. Our results provide the rationale for developing S101 to treat superantigen-induced toxic shock and other pathologies characterized by T-cell activation and proliferation.
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Affiliation(s)
- Alexei Shir
- Unit of Cellular Signaling, Silberman Life Sciences Institute, Hebrew University of Jerusalem, Safra Campus, Israel
| | - Shoshana Klein
- Unit of Cellular Signaling, Silberman Life Sciences Institute, Hebrew University of Jerusalem, Safra Campus, Israel
| | - Idit Sagiv-Barfi
- Unit of Cellular Signaling, Silberman Life Sciences Institute, Hebrew University of Jerusalem, Safra Campus, Israel
| | - Tamar Geiger
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Maya Zigler
- Unit of Cellular Signaling, Silberman Life Sciences Institute, Hebrew University of Jerusalem, Safra Campus, Israel
| | - Yael Langut
- Unit of Cellular Signaling, Silberman Life Sciences Institute, Hebrew University of Jerusalem, Safra Campus, Israel
| | - Nufar Edinger
- Unit of Cellular Signaling, Silberman Life Sciences Institute, Hebrew University of Jerusalem, Safra Campus, Israel
| | - Alexander Levitzki
- Unit of Cellular Signaling, Silberman Life Sciences Institute, Hebrew University of Jerusalem, Safra Campus, Israel
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Karau MJ, Tilahun ME, Krogman A, Osborne BA, Goldsby RA, David CS, Mandrekar JN, Patel R, Rajagopalan G. Passive therapy with humanized anti-staphylococcal enterotoxin B antibodies attenuates systemic inflammatory response and protects from lethal pneumonia caused by staphylococcal enterotoxin B-producing Staphylococcus aureus. Virulence 2017; 8:1148-1159. [PMID: 27925510 PMCID: PMC5711449 DOI: 10.1080/21505594.2016.1267894] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 11/21/2016] [Accepted: 11/28/2016] [Indexed: 02/08/2023] Open
Abstract
Drugs such as linezolid that inhibit bacterial protein synthesis may be beneficial in treating infections caused by toxigenic Staphylococcus aureus. As protein synthesis inhibitors have no effect on preformed toxins, neutralization of pathogenic exotoxins with anti-toxin antibodies may be beneficial in conjunction with antibacterial therapy. Herein, we evaluated the efficacy of human-mouse chimeric high-affinity neutralizing anti-staphylococcal enterotoxin B (SEB) antibodies in the treatment of experimental pneumonia caused by SEB-producing S. aureus. Since HLA class II transgenic mice mount a stronger systemic immune response following challenge with SEB and are more susceptible to SEB-induced lethal toxic shock than conventional mice strains, HLA-DR3 transgenic mice were used. Lethal pneumonia caused by SEB-producing S. aureus in HLA-DR3 transgenic mice was characterized by robust T cell activation and elevated systemic levels of several pro-inflammatory cytokines and chemokines. Prophylactic administration of a single dose of linezolid 30 min prior to the onset of infection attenuated the systemic inflammatory response and protected from mortality whereas linezolid administered 60 min after the onset of infection failed to confer significant protection. Human-mouse chimeric high-affinity neutralizing anti-SEB antibodies alone, but not polyclonal human IgG, mitigated this response and protected from death when administered immediately after initiation of infection. Further, anti-SEB antibodies as well as intact polyclonal human IgG, but not its Fab or Fc fragments, protected from lethal pneumonia when followed with linezolid therapy 60 min later. In conclusion, neutralization of superantigens with high-affinity antibodies may have beneficial effects in pneumonia.
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Affiliation(s)
- Melissa J. Karau
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Mulualem E. Tilahun
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, USA
- Department of Biology, Amherst College, Amherst, MA, USA
| | - Ashton Krogman
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Barbara A. Osborne
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, USA
| | | | - Chella S. David
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Jayawant N. Mandrekar
- Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Robin Patel
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
- Division of Infectious Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Govindarajan Rajagopalan
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN, USA
- Division of Infectious Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
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Abstract
Staphylococcal enterotoxin B is one of the most potent bacterial superantigens that exerts profound toxic effects upon the immune system, leading to stimulation of cytokine release and inflammation. It is associated with food poisoning, nonmenstrual toxic shock, atopic dermatitis, asthma, and nasal polyps in humans. Currently, there is no treatment or vaccine available. Passive immunotherapy using monoclonal antibodies made in several different species has shown significant inhibition in in vitro studies and reduction in staphylococcal enterotoxin B-induced lethal shock in in vivo studies. This should encourage future endeavors to develop these antibodies as therapeutic reagents.
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Xia T, Liang S, Wang H, Hu S, Sun Y, Yu X, Han J, Li J, Guo S, Dai J, Lou Z, Guo Y. Structural basis for the neutralization and specificity of Staphylococcal enterotoxin B against its MHC Class II binding site. MAbs 2014; 6:119-29. [PMID: 24423621 DOI: 10.4161/mabs.27106] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Staphylococcal enterotoxin (SE) B is among the potent toxins produced by Staphylococcus aureus that cause toxic shock syndrome (TSS), which can result in multi-organ failure and death. Currently, neutralizing antibodies have been shown to be effective immunotherapeutic agents against this toxin, but the structural basis of the neutralizing mechanism is still unknown. In this study, we generated a neutralizing monoclonal antibody, 3E2, against SEB, and analyzed the crystal structure of the SEB-3E2 Fab complex. Crystallographic analysis suggested that the neutralizing epitope overlapped with the MHC II molecule binding site on SEB, and thus 3E2 could inhibit SEB function by preventing interaction with the MHC II molecule. Mutagenesis studies were done on SEB, as well as the related Staphylococcus aureus toxins SEA and SEC. These studies revealed that tyrosine (Y)46 and lysine (K)71 residues of SEB are essential to specific antibody-antigen recognition and neutralization. Substitution of Y at SEA glutamine (Q)49, which corresponds to SEB Y46, increased both 3E2's binding to SEA in vitro and the neutralization of SEA in vivo. These results suggested that SEB Y46 is responsible for distinguishing SEB from SEA. These findings may be helpful for the development of antibody-based therapy for SEB-induced TSS.
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Affiliation(s)
- Tian Xia
- International Joint Cancer Institute; Second Military Medical University; Shanghai, P.R. China; College of Pharmacy; Liaocheng University; Liaocheng, P.R. China
| | - Shuaiyi Liang
- Laboratory of Structural Biology and MOE Laboratory of Protein Science; School of Medicine and Life Science; Tsinghua University; Beijing, P.R. China
| | - Huajing Wang
- International Joint Cancer Institute; Second Military Medical University; Shanghai, P.R. China; State Key Laboratory of Antibody Medicine and Targeting Therapy and Shanghai Key Laboratory of Cell Engineering and Antibody; Shanghai, P.R. China
| | - Shi Hu
- International Joint Cancer Institute; Second Military Medical University; Shanghai, P.R. China; State Key Laboratory of Antibody Medicine and Targeting Therapy and Shanghai Key Laboratory of Cell Engineering and Antibody; Shanghai, P.R. China
| | - Yuna Sun
- National Laboratory of Macromolecules; Institute of Biophysics; Chinese Academy of Science; Beijing, P.R. China
| | - Xiaojie Yu
- International Joint Cancer Institute; Second Military Medical University; Shanghai, P.R. China; State Key Laboratory of Antibody Medicine and Targeting Therapy and Shanghai Key Laboratory of Cell Engineering and Antibody; Shanghai, P.R. China
| | - Jun Han
- College of Pharmacy; Liaocheng University; Liaocheng, P.R. China
| | - Jun Li
- College of Pharmacy; Liaocheng University; Liaocheng, P.R. China
| | - Shangjing Guo
- College of Pharmacy; Liaocheng University; Liaocheng, P.R. China
| | - Jianxin Dai
- International Joint Cancer Institute; Second Military Medical University; Shanghai, P.R. China; State Key Laboratory of Antibody Medicine and Targeting Therapy and Shanghai Key Laboratory of Cell Engineering and Antibody; Shanghai, P.R. China; College of Pharmacy; Liaocheng University; Liaocheng, P.R. China
| | - Zhiyong Lou
- Laboratory of Structural Biology and MOE Laboratory of Protein Science; School of Medicine and Life Science; Tsinghua University; Beijing, P.R. China
| | - Yajun Guo
- International Joint Cancer Institute; Second Military Medical University; Shanghai, P.R. China; State Key Laboratory of Antibody Medicine and Targeting Therapy and Shanghai Key Laboratory of Cell Engineering and Antibody; Shanghai, P.R. China; College of Pharmacy; Liaocheng University; Liaocheng, P.R. China
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Models matter: the search for an effective Staphylococcus aureus vaccine. Nat Rev Microbiol 2014; 12:585-91. [PMID: 24998740 DOI: 10.1038/nrmicro3308] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Staphylococcus aureus is a highly successful bacterial pathogen owing to its abundance of cell surface and secreted virulence factors. It is estimated that 30% of the population is colonized with S. aureus, usually on mucosal surfaces, and methicillin-resistant S. aureus is a major public health concern. There have been multiple attempts to develop an S. aureus vaccine using one or more cell surface virulence factors as antigens; all of these vaccine trials have failed. In this Opinion article, we suggest that an over-reliance on rodent models and a focus on targeting cell surface components have been major contributing factors to this failure.
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Abstract
SUMMARY This review begins with a discussion of the large family of Staphylococcus aureus and beta-hemolytic streptococcal pyrogenic toxin T lymphocyte superantigens from structural and immunobiological perspectives. With this as background, the review then discusses the major known and possible human disease associations with superantigens, including associations with toxic shock syndromes, atopic dermatitis, pneumonia, infective endocarditis, and autoimmune sequelae to streptococcal illnesses. Finally, the review addresses current and possible novel strategies to prevent superantigen production and passive and active immunization strategies.
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Krakauer T. Update on staphylococcal superantigen-induced signaling pathways and therapeutic interventions. Toxins (Basel) 2013; 5:1629-54. [PMID: 24064719 PMCID: PMC3798877 DOI: 10.3390/toxins5091629] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 09/13/2013] [Accepted: 09/13/2013] [Indexed: 12/20/2022] Open
Abstract
Staphylococcal enterotoxin B (SEB) and related bacterial toxins cause diseases in humans and laboratory animals ranging from food poisoning, acute lung injury to toxic shock. These superantigens bind directly to the major histocompatibility complex class II molecules on antigen-presenting cells and specific Vβ regions of T-cell receptors (TCR), resulting in rapid hyper-activation of the host immune system. In addition to TCR and co-stimulatory signals, proinflammatory mediators activate signaling pathways culminating in cell-stress response, activation of NFκB and mammalian target of rapamycin (mTOR). This article presents a concise review of superantigen-activated signaling pathways and focuses on the therapeutic challenges against bacterial superantigens.
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Affiliation(s)
- Teresa Krakauer
- Department of Immunology, Integrated Toxicology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702 5011, USA.
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Krakauer T. PI3K/Akt/mTOR, a pathway less recognized for staphylococcal superantigen-induced toxicity. Toxins (Basel) 2012; 4:1343-66. [PMID: 23202320 PMCID: PMC3509712 DOI: 10.3390/toxins4111343] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 11/12/2012] [Accepted: 11/13/2012] [Indexed: 12/27/2022] Open
Abstract
Immunostimulating staphylococcal enterotoxin B (SEB) and related superantigenic toxins cause diseases in humans and laboratory animals by activating cells of the immune system. These toxins bind directly to the major histocompatibility complex (MHC) class II molecules on antigen-presenting cells and specific Vβ regions of T-cell receptors (TCR), resulting in hyperactivation of both T lymphocytes and monocytes/macrophages. Activated host cells produce excessive amounts of proinflammatory cytokines and chemokines, especially tumor necrosis factor α, interleukin 1 (IL-1), IL-2, interferon γ (IFNγ), and macrophage chemoattractant protein 1 causing clinical symptoms of fever, hypotension, and shock. The well-explored signal transduction pathways for SEB-induced toxicity downstream from TCR/MHC ligation and interaction of cell surface co-stimulatory molecules include the mitogen-activated protein kinase cascades and cytokine receptor signaling, culminating in NFκB activation. Independently, IL-2, IFNγ, and chemokines from activated T cells signal via the phosphoinositide 3-kinase (PI3K), the serine/threonine kinases, Akt and mammalian target of rapamycin (mTOR) pathways. This article reviews the signaling molecules induced by superantigens in the activation of PI3K/Akt/mTOR pathways leading to staphylococcal superantigen-induced toxicity and updates potential therapeutics against superantigens.
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Affiliation(s)
- Teresa Krakauer
- Department of Immunology, Integrated Toxicology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, USA.
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Tilahun AY, Karau MJ, Clark CR, Patel R, Rajagopalan G. The impact of tacrolimus on the immunopathogenesis of staphylococcal enterotoxin-induced systemic inflammatory response syndrome and pneumonia. Microbes Infect 2012; 14:528-36. [PMID: 22273732 DOI: 10.1016/j.micinf.2012.01.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 12/28/2011] [Accepted: 01/02/2012] [Indexed: 01/24/2023]
Abstract
Staphylococcal superantigens (SAg) are a family of potent exotoxins produced by Staphylococcus aureus. They play an important role in the pathogenesis of staphylococcal shock and pneumonia by causing a robust activation of the immune system and eliciting a strong surge in systemic cytokine and chemokine levels. Given the biological functions of SAg, we evaluated the efficacy of tacrolimus, a potent immunosuppressive agent, in the prophylaxis and therapy of staphylococcal TSS and pneumonia using human leukocyte antigen (HLA)-DR3 transgenic mice. Tacrolimus significantly inhibited staphylococcal SAg induced T cell activation in vitro. In vivo, tacrolimus significantly suppressed the SAg-induced elevation in serum cytokine and chemokine levels when given prophylactically, when administered immediately or even 2 h following systemic SAg challenge. Paradoxically, neither the prophylactic nor post-exposure treatment with tacrolimus protected mice from lethal SAg-induced TSS. A closer examination revealed that tacrolimus failed to suppress SAg-induced T cell proliferation and systemic pathology, including gut dysfunction. Tacrolimus also failed to protect from lethal pneumonia induced by a SAg-producing S. aureus strain. Thus, our study showed that even though T cell activation by SAg plays a major role in the immunopathogenesis of TSS and pneumonia, tacrolimus alone has no beneficial effect.
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Chimeric anti-staphylococcal enterotoxin B antibodies and lovastatin act synergistically to provide in vivo protection against lethal doses of SEB. PLoS One 2011; 6:e27203. [PMID: 22102880 PMCID: PMC3216929 DOI: 10.1371/journal.pone.0027203] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 10/12/2011] [Indexed: 11/19/2022] Open
Abstract
Staphylococcal enterotoxin B (SEB) is one of a family of toxins secreted by Staphylococcus aureus that act as superantigens, activating a large fraction of the T-cell population and inducing production of high levels of inflammatory cytokines that can cause toxic shock syndrome (TSS) and death. Extracellular engagement of the TCR of T-cells and class II MHC of antigen presenting cells by SEB triggers the activation of many intracellular signaling processes. We engineered chimeric antibodies to block the extracellular engagement of cellular receptors by SEB and used a statin to inhibit intracellular signaling. Chimeric human-mouse antibodies directed against different neutralizing epitopes of SEB synergistically inhibited its activation of human T-cells in vitro. In the in vivo model of lethal toxic shock syndrome (TSS) in HLA-DR3 transgenic mice, two of these antibodies conferred significant partial protection when administered individually, but offered complete protection in a synergistic manner when given together. Similarly, in vivo, lovastatin alone conferred only partial protection from TSS similar to single anti-SEB antibodies. However, used in combination with one chimeric neutralizing anti-SEB antibody, lovastatin provided complete protection against lethal TSS in HLA-DR3 transgenic mice. These experiments demonstrate that in vivo protection against lethal doses of SEB can be achieved by a statin of proven clinical safety and chimeric human-mouse antibodies, agents now widely used and known to be of low immunogenicity in human hosts.
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Human leukocyte antigen class II transgenic mouse model unmasks the significant extrahepatic pathology in toxic shock syndrome. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:2760-73. [PMID: 21641398 DOI: 10.1016/j.ajpath.2011.02.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2010] [Revised: 01/10/2011] [Accepted: 02/07/2011] [Indexed: 11/22/2022]
Abstract
Among the exotoxins produced by Staphylococcus aureus and Streptococcus pyogenes, the superantigens (SAgs) are the most potent T-cell activators known to date. SAgs are implicated in several serious diseases including toxic shock syndrome (TSS), Kawasaki disease, and sepsis. However, the immunopathogenesis of TSS and other diseases involving SAgs are still not completely understood. The commonly used conventional laboratory mouse strains do not respond robustly to SAgs in vivo. Therefore, they must be artificially rendered susceptible to TSS by using sensitizing agents such as d-galactosamine (d-galN), which skews the disease exclusively to the liver and, hence, is not representative of the disease in humans. SAg-induced TSS was characterized using transgenic mice expressing HLA class II molecules that are extremely susceptible to TSS without d-galN. HLA-DR3 transgenic mice recapitulated TSS in humans with extensive multiple-organ inflammation affecting the lung, liver, kidneys, heart, and small intestines. Heavy infiltration with T lymphocytes (both CD4(+) and CD8+), neutrophils, and macrophages was noted. In particular, the pathologic changes in the small intestines were extensive and accompanied by significantly altered absorptive functions of the enterocytes. In contrast to massive liver failure alone in the d-galN sensitization model of TSS, findings of the present study suggest that gut dysfunction might be a key pathogenic event that leads to high morbidity and mortality in humans with TSS.
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Arad G, Levy R, Nasie I, Hillman D, Rotfogel Z, Barash U, Supper E, Shpilka T, Minis A, Kaempfer R. Binding of superantigen toxins into the CD28 homodimer interface is essential for induction of cytokine genes that mediate lethal shock. PLoS Biol 2011; 9:e1001149. [PMID: 21931534 PMCID: PMC3172200 DOI: 10.1371/journal.pbio.1001149] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 08/02/2011] [Indexed: 01/04/2023] Open
Abstract
Bacterial superantigens, a diverse family of toxins, induce an inflammatory cytokine storm that can lead to lethal shock. CD28 is a homodimer expressed on T cells that functions as the principal costimulatory ligand in the immune response through an interaction with its B7 coligands, yet we show here that to elicit inflammatory cytokine gene expression and toxicity, superantigens must bind directly into the dimer interface of CD28. Preventing access of the superantigen to CD28 suffices to block its lethality. Mice were protected from lethal superantigen challenge by short peptide mimetics of the CD28 dimer interface and by peptides selected to compete with the superantigen for its binding site in CD28. Superantigens use a conserved β-strand/hinge/α-helix domain of hitherto unknown function to engage CD28. Mutation of this superantigen domain abolished inflammatory cytokine gene induction and lethality. Structural analysis showed that when a superantigen binds to the T cell receptor on the T cell and major histocompatibility class II molecule on the antigen-presenting cell, CD28 can be accommodated readily as third superantigen receptor in the quaternary complex, with the CD28 dimer interface oriented towards the β-strand/hinge/α-helix domain in the superantigen. Our findings identify the CD28 homodimer interface as a critical receptor target for superantigens. The novel role of CD28 as receptor for a class of microbial pathogens, the superantigen toxins, broadens the scope of pathogen recognition mechanisms.
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Affiliation(s)
- Gila Arad
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Revital Levy
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Iris Nasie
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Dalia Hillman
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Ziv Rotfogel
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Uri Barash
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Emmanuelle Supper
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Tomer Shpilka
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Adi Minis
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Raymond Kaempfer
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
- * E-mail:
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Brosnahan AJ, Schlievert PM. Gram-positive bacterial superantigen outside-in signaling causes toxic shock syndrome. FEBS J 2011; 278:4649-67. [PMID: 21535475 DOI: 10.1111/j.1742-4658.2011.08151.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Staphylococcus aureus and Streptococcus pyogenes (group A streptococci) are Gram-positive pathogens capable of producing a variety of bacterial exotoxins known as superantigens. Superantigens interact with antigen-presenting cells (APCs) and T cells to induce T cell proliferation and massive cytokine production, which leads to fever, rash, capillary leak and subsequent hypotension, the major symptoms of toxic shock syndrome. Both S. aureus and group A streptococci colonize mucosal surfaces, including the anterior nares and vagina for S. aureus, and the oropharynx and less commonly the vagina for group A streptococci. However, due to their abilities to secrete a variety of virulence factors, the organisms can also cause illnesses from the mucosa. This review provides an updated discussion of the biochemical and structural features of one group of secreted virulence factors, the staphylococcal and group A streptococcal superantigens, and their abilities to cause toxic shock syndrome from a mucosal surface. The main focus of this review, however, is the abilities of superantigens to induce cytokines and chemokines from epithelial cells, which has been linked to a dodecapeptide region that is relatively conserved among all superantigens and is distinct from the binding sites required for interactions with APCs and T cells. This phenomenon, termed outside-in signaling, acts to recruit adaptive immune cells to the submucosa, where the superantigens can then interact with those cells to initiate the final cytokine cascades that lead to toxic shock syndrome.
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Affiliation(s)
- Amanda J Brosnahan
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, USA
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Tilahun AY, Holz M, Wu TT, David CS, Rajagopalan G. Interferon gamma-dependent intestinal pathology contributes to the lethality in bacterial superantigen-induced toxic shock syndrome. PLoS One 2011; 6:e16764. [PMID: 21304813 PMCID: PMC3033413 DOI: 10.1371/journal.pone.0016764] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Accepted: 01/05/2011] [Indexed: 12/22/2022] Open
Abstract
Toxic shock syndrome (TSS) caused by the superantigen exotoxins of Staphylococcus aureus and Streptococcus pyogenes is characterized by robust T cell activation, profound elevation in systemic levels of multiple cytokines, including interferon-γ (IFN-γ), followed by multiple organ dysfunction and often death. As IFN-γ possesses pro- as well as anti-inflammatory properties, we delineated its role in the pathogenesis of TSS. Antibody-mediated in vivo neutralization of IFN-γ or targeted disruption of IFN-γ gene conferred significant protection from lethal TSS in HLA-DR3 transgenic mice. Following systemic high dose SEB challenge, whereas the HLA-DR3.IFN-γ+/+ mice became sick and succumbed to TSS, HLA-DR3.IFN-γ−/− mice appeared healthy and were significantly protected from SEB-induced lethality. SEB-induced systemic cytokine storm was significantly blunted in HLA-DR3.IFN-γ−/− transgenic mice. Serum concentrations of several cytokines (IL-4, IL-10, IL-12p40 and IL-17) and chemokines (KC, rantes, eotaxin and MCP-1) were significantly lower in HLA-DR3.IFN-γ−/− transgenic mice. However, SEB-induced T cell expansion in the spleens was unaffected and expansion of SEB-reactive TCR Vβ8+ CD4+ and CD8+ T cells was even more pronounced in HLA-DR3.IFN-γ−/− transgenic mice when compared to HLA-DR3.IFN-γ+/+ mice. A systematic histopathological examination of several vital organs revealed that both HLA-DR3.IFN-γ+/+ and HLA-DR3.IFN-γ−/− transgenic mice displayed comparable severe inflammatory changes in lungs, and liver during TSS. Remarkably, whereas the small intestines from HLA-DR3.IFN-γ+/+ transgenic mice displayed significant pathological changes during TSS, the architecture of small intestines in HLA-DR3.IFN-γ−/− transgenic mice was preserved. In concordance with these histopathological changes, the gut permeability to macromolecules was dramatically increased in HLA-DR3.IFN-γ+/+ but not HLA-DR3.IFN-γ−/− mice during TSS. Overall, IFN-γ seemed to play a lethal role in the immunopathogenesis of TSS by inflicting fatal small bowel pathology. Our study thus identifies the important role for IFN-γ in TSS.
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Affiliation(s)
- Ashenafi Y. Tilahun
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Marah Holz
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Tsung-Teh Wu
- Department of Anatomic Pathology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Chella S. David
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Govindarajan Rajagopalan
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
- * E-mail:
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Varshney AK, Wang X, Cook E, Dutta K, Scharff MD, Goger MJ, Fries BC. Generation, characterization, and epitope mapping of neutralizing and protective monoclonal antibodies against staphylococcal enterotoxin B-induced lethal shock. J Biol Chem 2011; 286:9737-47. [PMID: 21233204 DOI: 10.1074/jbc.m110.212407] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
T-cell stimulating activity of Staphylococcal enterotoxin B (SEB) is an important factor in the pathogenesis of certain staphylococcal diseases including SEB mediated shock. SEB is one of the most potent superantigens known and treatment of SEB induced shock remains a challenge. We generated and characterized murine monoclonal antibodies (mAbs) to SEB in mice. We tested mAbs neutralize mitogenic effects of SEB in vitro and in vivo with T-cell proliferation assays and 2 murine models for SEB induced lethal shock (SEBILS). Epitope mapping suggests that all these mAbs recognize conformational epitopes that are destroyed by deleting the C terminus of the protein. Further site-directed mutagenesis identified potential residues involved in binding to SEB that differ between Methicillin resistant and sensitive Staphylococcus aureus strains. Only mAb 20B1 was effective as a monotherapy in treating SEBILS in HLA DR3 transgenic mice, which exhibit enhanced sensitivity to SEB. It is noteworthy that mAbs, 14G8 and 6D3 were not protective when given alone in the HLA DR3 mice but their efficacy of protection could be greatly enhanced when mAbs were co-administered simultaneously. Our data suggest combinations of defined mAbs may constitute a better treatment strategy and provide a new insight for the development of passive immunotherapy.
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Affiliation(s)
- Avanish K Varshney
- Department of Medicine (Infectious Diseases), Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Therapeutic down-modulators of staphylococcal superantigen-induced inflammation and toxic shock. Toxins (Basel) 2010; 2:1963-83. [PMID: 22069668 PMCID: PMC3153276 DOI: 10.3390/toxins2081963] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 07/16/2010] [Accepted: 07/28/2010] [Indexed: 12/21/2022] Open
Abstract
Staphylococcal enterotoxin B (SEB) and related superantigenic toxins are potent stimulators of the immune system and cause a variety of diseases in humans, ranging from food poisoning to toxic shock. These toxins bind directly to major histocompatibility complex (MHC) class II molecules on antigen-presenting cells and specific Vβ regions of T-cell receptors (TCR), resulting in hyperactivation of both monocytes/macrophages and T lymphocytes. Activated host cells produce massive amounts of proinflammatory cytokines and chemokines, activating inflammation and coagulation, causing clinical symptoms that include fever, hypotension, and shock. This review summarizes the in vitro and in vivo effects of staphylococcal superantigens, the role of pivotal mediators induced by these toxins in the pathogenic mechanisms of tissue injury, and the therapeutic agents to mitigate the toxic effects of superantigens.
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Tilahun AY, Theuer JE, Patel R, David CS, Rajagopalan G. Detrimental effect of the proteasome inhibitor, bortezomib in bacterial superantigen- and lipopolysaccharide-induced systemic inflammation. Mol Ther 2010; 18:1143-54. [PMID: 20372109 DOI: 10.1038/mt.2010.53] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Bacterial superantigen (BSAg)-induced toxic shock syndrome (TSS) and bacterial lipopolysaccharide (LPS)-induced shock are characterized by severe systemic inflammation. As nuclear factor kappaB (NF kappaB) plays an important role in inflammation and bortezomib, a proteasome inhibitor widely used in cancer chemotherapy, is a potent inhibitor of NF kappaB activation, we evaluated the therapeutic and prophylactic use of bortezomib in these conditions using murine models. Bortezomib prophylaxis significantly reduced serum levels of many cytokines and chemokines induced by BSAg. However, at 3 hours, serum level of TNF-a, an important cytokine implicated in TSS, was significantly reduced but not abolished. At 6 hours, there was no difference in the serum TNF-a levels between bortezomib treated and untreated mice challenged with staphylococcal enterotoxin B (SEB). Paradoxically, all mice treated with bortezomib either before or after BSAg challenge succumbed to TSS. Neither bortezomib nor BSAg was lethal if given alone. Serum biochemical parameters and histopathological findings suggested acute liver failure as the possible cause of mortality. Liver tissue from SEB-challenged mice treated with bortezomib showed a significant reduction in NF kappaB activation. Because NF kappaB-dependent antiapoptotic pathways protect hepatocytes from TNF-alpha-induced cell death, inhibition of NF kappaB brought forth by bortezomib in the face of elevated TNF-alpha levels caused by BSAg or LPS is detrimental.
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Affiliation(s)
- Ashenafi Y Tilahun
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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23
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Potent neutralization of staphylococcal enterotoxin B by synergistic action of chimeric antibodies. Infect Immun 2010; 78:2801-11. [PMID: 20308304 DOI: 10.1128/iai.01121-09] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Staphylococcal enterotoxin B (SEB), a shock-inducing exotoxin synthesized by Staphylococcus aureus, is an important cause of food poisoning and is a class B bioterrorism agent. SEB mediates antigen-independent activation of a major subset of the T-cell population by cross-linking T-cell receptors (TCRs) with class II major histocompatibility complex (MHC-II) molecules of antigen-presenting cells, resulting in the induction of antigen independent proliferation and cytokine secretion by a significant fraction of the T-cell population. Neutralizing antibodies inhibit SEB-mediated T-cell activation by blocking the toxin's interaction with the TCR or MHC-II and provide protection against the debilitating effects of this superantigen. We derived and searched a set of monoclonal mouse anti-SEB antibodies to identify neutralizing anti-SEB antibodies that bind to different sites on the toxin. A pair of non-cross-reactive, neutralizing anti-SEB monoclonal antibodies (MAbs) was found, and a combination of these antibodies inhibited SEB-induced T-cell proliferation in a synergistic rather than merely additive manner. In order to engineer antibodies more suitable than mouse MAbs for use in humans, the genes encoding the VL and VH gene segments of a synergistically acting pair of mouse MAbs were grafted, respectively, onto genes encoding the constant regions of human Igkappa and human IgG1, transfected into mammalian cells, and used to generate chimeric versions of these antibodies that had affinity and neutralization profiles essentially identical to their mouse counterparts. When tested in cultures of human peripheral blood mononuclear cells or splenocytes derived from HLA-DR3 transgenic mice, the chimeric human-mouse antibodies synergistically neutralized SEB-induced T-cell activation and cytokine production.
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Abstract
Bacterial superantigens are a family of exotoxins that are the most potent T-cell activators known. Because of their ability to induce strong immune activation, superantigens have been implicated in a variety of diseases ranging from self-limiting food poisoning to more severe toxic shock syndrome (TSS) and have the potential to be used as agents of bioterrorism. Nonetheless, the precise molecular mechanisms by which T-cell activation by superantigens lead to acute systemic inflammatory response, multiple organ dysfunction, and ultimately death are unclear. Inadequate understanding of the pathogenesis has resulted in lack of development of effective therapy for superantigen-induced TSS. To fill these deficiencies, we systematically dissected the molecular pathogenesis of superantigen-induced TSS using the humanized human leukocyte antigen-DR3 transgenic mouse model by microarray-based gene expression profiling. Splenic expression of prostaglandin-endoperoxide synthase 2 (PTGS-2; also called cyclooxygenase 2 or COX-2) gene was increased by several hundred folds shortly after systemic superantigen (staphylococcal enterotoxin B [SEB]) exposure. In addition, expressions of several genes associated with eicosanoid pathway were significantly modulated by SEB, as analyzed by dedicated software. Given the importance of the COX-2 pathway in inflammation, we examined whether therapeutic inhibition of COX-2 by a highly selective inhibitor, CAY10404, could be beneficial. Our studies showed that i.p. administration of CAY10404 (50 mg/kg) immediately after challenge with 10 microg of SEB was unable to inhibit SEB-induced in vivo cytokine/chemokine production or T-cell activation/proliferation and did not prevent superantigen-associated thymocyte apoptosis.
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Rajagopalan G, Tilahun AY, Asmann YW, David CS. Early gene expression changes induced by the bacterial superantigen staphylococcal enterotoxin B and its modulation by a proteasome inhibitor. Physiol Genomics 2009; 37:279-93. [PMID: 19336531 DOI: 10.1152/physiolgenomics.90385.2008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Toxic shock syndrome (TSS) is an acute, serious systemic illness caused by bacterial superantigens. Nonavailability of a suitable animal model until recently has hampered an in-depth understanding of the pathogenesis of TSS. In the current study, we characterized the early molecular events underlying TSS using our HLA-DR3 transgenic mouse model. Gene expression profiling using DNA microarrays identified a rapid and significant upregulation of several pro- as well as anti-inflammatory mediators, many of which have never been previously described in TSS. In vivo administration of staphylococcal enterotoxin B (SEB) led to an increase in the expression of Th0- (IL-2, 240-fold); Th1- (IFN-gamma, 360-fold; IL-12, 8-fold); Th2- (IL-4, 53-fold; IL-5, 4-fold) as well as Th17-type cytokines (IL-21, 19-fold; IL-17, 5-fold). The immunoregulatory cytokines (IL-6, 700-fold; IL-10, 18-fold); CC chemokines (such as CCL 2, 11, 3, 24, 17, 12, 7), CXC chemokines (such as CXCL 1, 2, 5, 11, 10, 19); and several proteases (matrix metalloproteinases 13, 8, 3, and 9) were also upregulated. Serum levels of several of these cytokines/chemokines were also significantly elevated. Pathway analyses revealed significant modulation in a variety of biochemical and cellular functions, providing molecular insights into the pathogenesis of TSS. Administration of bortezomib, a clinically approved proteasome inhibitor capable of blocking NF-kappaB pathway, was able to significantly modulate the expression of a variety of genes induced by SEB. Thus, our study showed that TSS is a complex process and emphasized the potential of use of bortezomib in the therapy of superantigen-induced TSS.
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Brosnahan AJ, Schaefers MM, Amundson WH, Mantz MJ, Squier CA, Peterson ML, Schlievert PM. Novel toxic shock syndrome toxin-1 amino acids required for biological activity. Biochemistry 2009; 47:12995-3003. [PMID: 19012411 DOI: 10.1021/bi801468w] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Superantigens interact with T lymphocytes and macrophages to cause T lymphocyte proliferation and overwhelming cytokine production, which lead to toxic shock syndrome. Staphylococcus aureus superantigen toxic shock syndrome toxin-1 is a major cause of menstrual toxic shock syndrome. In general, superantigen-secreting S. aureus remains localized at the vaginal surface, and the superantigen must therefore penetrate the vaginal mucosa to interact with underlying immune cells to cause toxic shock syndrome. A dodecapeptide region (toxic shock syndrome toxin-1 amino acids F119-D130), relatively conserved among superantigens, has been implicated in superantigen penetration of the epithelium. The purpose of this study was to determine amino acids within this dodecapeptide region that are required for interaction with vaginal epithelium. Alanine mutations were constructed in S. aureus toxic shock syndrome toxin-1 amino acids D120 to D130. All mutants maintained superantigenicity, and selected mutants were lethal when given intravenously to rabbits. Toxic shock syndrome toxin-1 induces interleukin-8 from immortalized human vaginal epithelial cells; however, three toxin mutants (S127A, T128A, and D130A) induced low levels of interleukin-8 compared to wild type toxin. When carboxy-terminal mutants (S127A to D130A) were administered vaginally to rabbits, D130A was nonlethal, while S127A and T128A demonstrated delayed lethality compared to wild type toxin. In a porcine ex vivo permeability model, mutant D130A penetrated the vaginal mucosa more quickly than wild type toxin. Toxic shock syndrome toxin-1 residue D130 may contribute to binding an epithelial receptor, which allows it to penetrate the vaginal mucosa, induce interleukin-8, and cause toxic shock syndrome.
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Affiliation(s)
- Amanda J Brosnahan
- Department of Microbiology, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, Minnesota 55455, USA
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Abstract
Population studies have shown that among all the genetic factors linked with autoimmune disease development, MHC class II genes on chromosome 6 accounts for majority of familial clustering in the common autoimmune diseases. Despite the highly polymorphic nature of HLA class II genes, majority of autoimmune diseases are linked to a limited set of class II-DR or -DQ alleles. Thus a more detailed study of these HLA-DR and -DQ alleles were needed to understand their role in genetic predisposition and pathogenesis of autoimmune diseases. Although in vitro studies using class-II restricted CD4 T cells and purified class II molecules have helped us in understanding some aspects of HLA class-II association with disease, it is difficult to study the role of class II genes in vivo because of heterogeneity of human population, complexity of MHC, and strong linkage disequilibrium among different class II genes. To overcome this problem, we pioneered the generation of HLA-class II transgenic mice to study role of these molecule in inflammatory disease. These HLA class II transgenic mice were used to develop novel in vivo disease model for common autoimmune diseases such as rheumatoid arthritis, multiple sclerosis, insulin-dependent diabetes mellitus, myasthenia gravis, celiac disease, autoimmune relapsing polychondritis, autoimmune myocarditis, thyroiditis, uveitis, as well as other inflammatory disease such as allergy, tuberculosis and toxic shock syndrome. As the T-cell repertoire in these humanized HLA transgenic mice are shaped by human class II molecules, they show the same HLA restriction as humans, implicate potential triggering mechanism and autoantigens, and identify similar antigenic epitopes seen in human. This review describes the value of these humanized transgenic mice in deciphering role of HLA class II molecules in immunopathogenesis of inflammatory diseases.
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Rajagopalan G, Polich G, Sen MM, Singh M, Epstein BE, Lytle AK, Rouse MS, Patel R, David CS. Evaluating the role of HLA-DQ polymorphisms on immune response to bacterial superantigens using transgenic mice. ACTA ACUST UNITED AC 2007; 71:135-45. [PMID: 18086265 DOI: 10.1111/j.1399-0039.2007.00986.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bacterial superantigens bind directly to human leukocyte antigen (HLA) class II molecules and vigorously activate T cells expressing certain T-cell receptor variable region families. As interaction with HLA class II molecules is the primary step in this process, polymorphic variations in HLA class II can determine the extent of superantigen binding to HLA class II molecules, govern the magnitude of immune activation induced by given superantigens and determine the outcome of superantigen-mediated diseases. As direct assessment of the influence of HLA class II polymorphism in humans is impossible because of expression of more than one HLA class II alleles in a given individual and toxicity of superantigens, transgenic mice expressing HLA-DQ6 (HLA-DQA1*0103 and HLA-DQB1*0601) and HLA-DQ8 (HLA-DQA1*0301 and HLA-DQB1*0302) were used to achieve this goal. HLA-DQ6 and HLA-DQ8 elicited comparable in vitro and in vivo immune response to staphylococcal enterotoxins (SE) A, SEB, SEH and SEK, toxic shock syndrome toxin-1, streptococcal pyrogenic exotoxin (SPE) A and SPEC and streptococcal mitogenic exotoxin Z (SMEZ). However, each superantigen had a unique T-cell receptor activation profile. In vivo challenge with Streptococcus pyogenes, H305, capable of elaborating SPEA and SMEZ, yielded a similar clinical outcome in HLA-DQ6 and HLA-DQ8 transgenic mice. In conclusion, HLA-DQ6 and HLA-DQ8 elicited comparable response to certain bacterial superantigens. Our report highlights the advantages of HLA class II transgenic mice in such studies.
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Affiliation(s)
- G Rajagopalan
- Department of Immunology, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN 55905, USA.
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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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Cook E, Wang X, Robiou N, Fries BC. Measurement of staphylococcal enterotoxin B in serum and culture supernatant with a capture enzyme-linked immunosorbent assay. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2007; 14:1094-101. [PMID: 17634506 PMCID: PMC2043325 DOI: 10.1128/cvi.00183-07] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Staphylococcal enterotoxin B (SEB) is a select agent because it is a potent mitogen that elicits life-threatening polyclonal T-cell proliferation and cytokine production at very low concentrations. Efforts are in progress to develop therapeutic reagents and vaccines that neutralize or prevent the devastating effects of this toxin. Because of its rapid binding to in vivo receptors, this toxin is difficult to detect in serum. This rapid binding also constitutes a major challenge for the development of effective therapeutic reagents that can neutralize the effects of the toxin in vivo. We have developed a highly sensitive capture enzyme-linked immunosorbent assay that detects SEB in body fluids at very low levels. With this assay, the peak levels of SEB in serum and renal clearance can be measured in mice. After either oral ingestion or nasal inhalation of SEB by mice, this assay documents the transcytosis of SEB across the mucosal membranes into serum within 2 h. Furthermore, this assay was used to compare the SEB levels in different murine models for SEB-induced lethal shock and demonstrated that the coadministration of toxin-enhancing chemicals, such as D-galactosamine and lipopolysaccharide, can alter the peak serum SEB levels. Hence, this assay is a potentially useful tool for the study of the pharmacokinetics of SEB and the effects of potential therapeutic reagents on serum SEB levels.
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Affiliation(s)
- E Cook
- Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park, Bronx, NY 10461, USA
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Rajagopalan G, Smart MK, Patel R, David CS. Acute systemic immune activation following conjunctival exposure to staphylococcal enterotoxin B. Infect Immun 2006; 74:6016-9. [PMID: 16988282 PMCID: PMC1594882 DOI: 10.1128/iai.00671-06] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Conjunctival exposure to the Staphylococcus aureus superantigen staphylococcal enterotoxin B (SEB) may occur accidentally, as a result of bioterrorism, or during colonization or infection of the external eye. Using human leukocyte antigen class II transgenic mice, we show for the first time that conjunctival exposure to SEB can cause robust systemic immune activation.
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Affiliation(s)
- Govindarajan Rajagopalan
- Department of Immunology, Mayo Clinic College of Medicine, 200 First St., SW, Rochester, MN 55905, USA
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Rajagopalan G, Sen MM, Singh M, Murali NS, Nath KA, Iijima K, Kita H, Leontovich AA, Gopinathan U, Patel R, David CS. INTRANASAL EXPOSURE TO STAPHYLOCOCCAL ENTEROTOXIN B ELICITS AN ACUTE SYSTEMIC INFLAMMATORY RESPONSE. Shock 2006; 25:647-56. [PMID: 16721274 DOI: 10.1097/01.shk.0000209565.92445.7d] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Staphylococcus aureus produces a variety of superantigen exotoxins, including staphylococcal enterotoxin B (SEB). Little is known regarding the pathogenesis of SEB entering through the intranasal route. Intranasal exposure to SEB might occur because of nasal packing following surgical procedure, biologic warfare, or even S. aureus colonization. We evaluated the local and systemic effects of intranasally delivered SEB using a series of human leukocyte antigen (HLA) class II transgenic mice as conventional mice expressing endogenous class II molecules mount a poor immune response to SEB. Gene expression profiling using microarrays showed robust up-regulation of genes involved in several proinflammatory pathways as early as 3 h post-intranasal challenge with SEB in HLA class II transgenic mice. This was accompanied by a several hundred-fold increase in serum levels of pro-inflammatory cytokines such as IL-12, IL-6, TNF-alpha, IFN-gamma, as well as MCP-1 in HLA class II transgenic mice but not in C57BL/6 mice; CD4 or CD8 T-cells independently contributed to the systemic cytokine response. Defective IL-12 or IL-4 receptor signaling significantly decreased or increased serum IFN-gamma, respectively. Intranasal exposure to SEB resulted in neutrophil influx into bronchoalveolar lavage fluid and caused expansion of both CD4 and CD8 T-cells expressing TCR V beta 8 in the spleen. This was accompanied by mononuclear cell infiltration in the liver reminiscent of the systemic inflammatory response syndrome. Thus, we have shown, for the first time, that intranasal administration of SEB can cause systemic immune activation.
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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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Rajagopalan G, Iijima K, Singh M, Kita H, Patel R, David CS. Intranasal exposure to bacterial superantigens induces airway inflammation in HLA class II transgenic mice. Infect Immun 2006; 74:1284-96. [PMID: 16428778 PMCID: PMC1360368 DOI: 10.1128/iai.74.2.1284-1296.2006] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus is widely prevalent in the nasopharynges of healthy individuals (carriers) but can also cause serious infections. S. aureus can elaborate a variety of superantigen exotoxins in "carrier" or "pathogenic" states. Streptococcus pyogenes can also colonize the nasopharynx and elaborate superantigens. Unlike the acute effects of superantigen exotoxins absorbed through the gut or vaginal mucosa, little is known regarding the pathogenesis of superantigens entering through the intranasal route. In the current study, we evaluated the local and systemic effects of staphylococcal enterotoxin B (SEB) and streptococcal pyrogenic exotoxin A (SPEA) delivered through the intranasal route. Superantigens were administered intranasally on multiple occasions, and experimental animals were sacrificed on day 8 for experimental analyses. SEB-induced airway inflammation was more pronounced for HLA-DR3 transgenic mice than for BALB/c mice, consistent with bacterial superantigens binding more efficiently to human than murine major histocompatibility complex class II. The nature of the airway inflammation in HLA-DR3 mice was determined by the concentration of SEB applied intranasally. Low concentrations (20 ng) induced eosinophilic airway inflammation as well as eosinophil degranulation, whereas intranasal exposure to higher concentrations (2,000 ng) resulted in neutrophilic airway inflammation, permanent airway destruction, toxic shock, and mortality. SEB-induced eosinophilic inflammatory response was enhanced in signal transducer and activator of transcription (STAT)-4-deficient HLA-DQ8 transgenic mice with defective interleukin-12 signaling. Intranasal administration of SPEA induced airway inflammation and systemic immune activation in HLA-DQ8 transgenic mice. In conclusion, repeated chronic intranasal exposure to bacterial superantigens causes airway inflammation and systemic immune activation.
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Affiliation(s)
- Govindarajan Rajagopalan
- Department of Immunology, Mayo Clinic College of Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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Krakauer T, Little SF, Stiles BG. Bacillus anthracis edema toxin inhibits Staphylococcus aureus enterotoxin B effects in vitro: a potential protein therapeutic? Infect Immun 2005; 73:7069-73. [PMID: 16177395 PMCID: PMC1230970 DOI: 10.1128/iai.73.10.7069-7073.2005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Various in vitro effects of staphylococcal enterotoxin B (SEB) on human peripheral blood mononuclear cells were mitigated by Bacillus anthracis edema toxin. In particular, levels of some SEB-induced cytokines (tumor necrosis factor alpha, gamma interferon) and chemokines (monocyte chemoattractant protein 1, macrophage inflammatory protein 1 alpha [MIP-1alpha], MIP-1beta) were significantly diminished or even nonexistent, depending upon the timing of edema toxin administration. Overall, these results suggest a novel use of B. anthracis edema toxin against a bacterial superantigen.
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Affiliation(s)
- Teresa Krakauer
- Integrated Toxicology, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702-5011, USA
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Rajagopalan G, Singh M, Sen MM, Murali NS, Nath KA, David CS. Endogenous superantigens shape response to exogenous superantigens. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2005; 12:1119-22. [PMID: 16148182 PMCID: PMC1235787 DOI: 10.1128/cdli.12.9.1119-1122.2005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Endogenous superantigen-mediated thymic negative selection resulted in a paucity of mature T cells bearing T-cell receptor (TCR) Vbeta8 in the periphery. Consequently, the magnitude of immune response to exogenous superantigen staphylococcal enterotoxin B, which activates TCR Vbeta8(+) T cells, was significantly reduced and conferred protection from superantigen-induced mortality.
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Affiliation(s)
- Govindarajan Rajagopalan
- Department of Immunology, Mayo Clinic College of Medicine, Mayo Clinic, SW, Rochester, MN 55905, USA
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Altmann D. Antagonist peptide for the treatment of bacterial superantigen toxic shock in a clinical or biowarfare setting. Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.15.6.741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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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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