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Kim SO, Park I, Vernet T, Moreau C, Hong S, Park TH. Duffy Antigen Receptor for Chemokines (DARC) Nanodisc-Based Biosensor for Detection of Staphylococcal Bicomponent Pore-Forming Leukocidins. ACS APPLIED MATERIALS & INTERFACES 2024; 16:37390-37400. [PMID: 39007843 DOI: 10.1021/acsami.4c02079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Staphylococcus aureus (S. aureus) is an opportunistic infectious pathogen, which causes a high mortality rate during bloodstream infections. The early detection of virulent strains in patients' blood samples is of medical interest for rapid diagnosis. The main virulent factors identified in patient isolates include leukocidins that bind to specific membrane receptors and lyse immune cells and erythrocytes. Duffy antigen receptor for chemokines (DARC) on the surface of specific cells is a main target of leukocidins such as gamma-hemolysin AB (HlgAB) and leukocidin ED (LukED). Among them, HlgAB is a conserved and critical leukocidin that binds to DARC and forms pores on the cell membranes, leading to cell lysis. Current methods are based on ELISA or bacterial culture, which takes hours to days. For detecting HlgAB with faster response and higher sensitivity, we developed a biosensor that combines single-walled carbon nanotube field effect transistors (swCNT-FETs) with immobilized DARC receptors as biosensing elements. DARC was purified from a bacterial expression system and successfully reconstituted into nanodiscs that preserve binding capability for HlgAB. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) showed an increase of the DARC-containing nanodisc size in the presence of HlgAB, indicating the formation of HlgAB prepore or pore complexes. We demonstrate that this sensor can specifically detect the leukocidins HlgA and HlgAB in a quantitative manner within the dynamic range of 1 fM to 100 pM with an LOD of 0.122 fM and an LOQ of 0.441 fM. The sensor was challenged with human serum spiked with HlgAB as simulated clinical samples. After dilution for decreasing nonspecific binding, it selectively detected the toxin with a similar detection range and apparent dissociation constant as in the buffer. This biosensor was demonstrated with remarkable sensitivity to detect HlgAB rapidly and has the potential as a tool for fundamental research and clinical applications, although this sensor cannot differentiate between HlgAB and LukED as both have the same receptor.
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Affiliation(s)
- So-Ong Kim
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea
| | - Inkyoung Park
- Department of Physics and Astronomy, Institute of Applied Physics, Seoul National University, Seoul 08826, Republic of Korea
| | - Thierry Vernet
- Univ. Grenoble Alpes, CNRS, CEA, IBS, Grenoble F-38000, France
| | | | - Seunghun Hong
- Department of Physics and Astronomy, Institute of Applied Physics, Seoul National University, Seoul 08826, Republic of Korea
| | - Tai Hyun Park
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea
- Department of Nutritional Science and Food Management, Ewha Womans University, Seoul 03760, Republic of Korea
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2
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Lichota A, Gwozdzinski K, Kowalczyk E, Kowalczyk M, Sienkiewicz M. Contribution of staphylococcal virulence factors in the pathogenesis of thrombosis. Microbiol Res 2024; 283:127703. [PMID: 38537329 DOI: 10.1016/j.micres.2024.127703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 03/20/2024] [Accepted: 03/20/2024] [Indexed: 04/17/2024]
Abstract
Staphylococci are responsible for many infections in humans, starting with skin and soft tissue infections and finishing with invasive diseases such as endocarditis, sepsis and pneumonia, which lead to high mortality. Patients with sepsis often demonstrate activated clotting pathways, decreased levels of anticoagulants, decreased fibrinolysis, activated endothelial surfaces and activated platelets. This results in disseminated intravascular coagulation and formation of a microthrombus, which can lead to a multiorgan failure. This review describes various staphylococcal virulence factors that contribute to vascular thrombosis, including deep vein thrombosis in infected patients. The article presents mechanisms of action of different factors released by bacteria in various host defense lines, which in turn can lead to formation of blood clots in the vessels.
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Affiliation(s)
- Anna Lichota
- Department of Pharmaceutical Microbiology and Microbiological Diagnostics, Medical University of Lodz, Lodz, Poland.
| | | | - Edward Kowalczyk
- Department of Pharmacology and Toxicology, Medical University of Lodz, Lodz, Poland
| | | | - Monika Sienkiewicz
- Department of Pharmaceutical Microbiology and Microbiological Diagnostics, Medical University of Lodz, Lodz, Poland
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3
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Zou X, Cai S, Wang T, Zheng S, Cui X, Hao J, Chen X, Liu Y, Zhang Z, Li Y. Natural antibacterial agent-based nanoparticles for effective treatment of intracellular MRSA infection. Acta Biomater 2023; 169:410-421. [PMID: 37557944 DOI: 10.1016/j.actbio.2023.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 07/17/2023] [Accepted: 08/03/2023] [Indexed: 08/11/2023]
Abstract
Intracellular MRSA is extremely difficult to eradicate by traditional antibiotics, leading to infection dissemination and drug resistance. A general lack of facile and long-term strategies to effectively eliminate intracellular MRSA. In this study, glabridin (GLA)-loaded pH-responsive nanoparticles (NPs) were constructed using cinnamaldehyde (CA)-dextran conjugates as carriers. These NPs targeted infected macrophages/MRSA via dextran mediation and effectively accumulated at the MRSA infection site. The NPs were then destabilized in response to the low pH of the lysosomes, which triggered the release of CA and GLA. The released CA downregulated the expression of cytotoxic pore-forming toxins, thereby decreasing the damage of macrophage and risk of the intracellular bacterial dissemination. Meanwhile, GLA could rapidly kill intracellularly entrapped MRSA with a low possibility of developing resistance. Using a specific combination of the natural antibacterial agents CA and GLA, NPs effectively eradicated intracellular MRSA with low toxicity to normal tissues in a MRSA-induced peritonitis model. This strategy presents a potential alternative for enhancing intracellular MRSA therapy, particularly for repeated and long-term clinical applications. STATEMENT OF SIGNIFICANCE: Intracellular MRSA infections are a growing threat to public health, and there is a general lack of a facile strategy for efficiently eliminating intracellular MRSA while reducing the ever-increasing drug resistance. In this study, pH-responsive and macrophage/MRSA-targeting nanoparticles were prepared by conjugating the phytochemical cinnamaldehyde to dextran to encapsulate the natural antibacterial agent glabridin. Using a combination of traditional Chinese medicine, the NPs significantly increased drug accumulation in MRSA and showed superior intracellular and extracellular bactericidal activity. Importantly, the NPs can inhibit potential intracellular bacteria dissemination and reduce the development of drug resistance, thus allowing for repeated treatment. Natural antibacterial agent-based drug delivery systems are an attractive alternative for facilitating the clinical treatment of intracellular MRSA infections.
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Affiliation(s)
- Xinshu Zou
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China; Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin 150030, PR China
| | - Shuang Cai
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China; Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin 150030, PR China
| | - Tingting Wang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China; Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin 150030, PR China
| | - Sidi Zheng
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China; Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin 150030, PR China
| | - Xilong Cui
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China; Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin 150030, PR China
| | - Jingyou Hao
- Harbin Lvdasheng Animal Medicine Manufacture Co., Ltd., Harbin 150000, PR China
| | - Xueying Chen
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China; Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin 150030, PR China
| | - Yanyan Liu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China; Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin 150030, PR China
| | - Zhiyun Zhang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China; Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin 150030, PR China.
| | - Yanhua Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China; Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin 150030, PR China.
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4
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Le H, Dé E, Le Cerf D, Karakasyan C. Using Targeted Nano-Antibiotics to Improve Antibiotic Efficacy against Staphylococcus aureus Infections. Antibiotics (Basel) 2023; 12:1066. [PMID: 37370385 DOI: 10.3390/antibiotics12061066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 06/15/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
The poor bioavailability of antibiotics at infection sites is one of the leading causes of treatment failure and increased bacterial resistance. Therefore, developing novel, non-conventional antibiotic delivery strategies to deal with bacterial pathogens is essential. Here, we investigated the encapsulation of two fluoroquinolones, ciprofloxacin and levofloxacin, into polymer-based nano-carriers (nano-antibiotics), with the goal of increasing their local bioavailability at bacterial infection sites. The formulations were optimized to achieve maximal drug loading. The surfaces of nano-antibiotics were modified with anti-staphylococcal antibodies as ligand molecules to target S. aureus pathogens. The interaction of nano-antibiotics with the bacterial cells was investigated via fluorescent confocal microscopy. Conventional tests (MIC and MBC) were used to examine the antibacterial properties of nano-antibiotic formulations. Simultaneously, a bioluminescence assay model was employed, revealing the rapid and efficient assessment of the antibacterial potency of colloidal systems. In comparison to the free-form antibiotic, the targeted nano-antibiotic exhibited enhanced antimicrobial activity against both the planktonic and biofilm forms of S. aureus. Furthermore, our data suggested that the efficacy of a targeted nano-antibiotic treatment can be influenced by its antibiotic release profile.
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Affiliation(s)
- Hung Le
- Sciences & Technic Faculty, Univ Rouen Normandie, INSA Rouen Normandie, CNRS, PBS UMR 6270, 76000 Rouen, France
| | - Emmanuelle Dé
- Sciences & Technic Faculty, Univ Rouen Normandie, INSA Rouen Normandie, CNRS, PBS UMR 6270, 76000 Rouen, France
| | - Didier Le Cerf
- Sciences & Technic Faculty, Univ Rouen Normandie, INSA Rouen Normandie, CNRS, PBS UMR 6270, 76000 Rouen, France
| | - Carole Karakasyan
- Sciences & Technic Faculty, Univ Rouen Normandie, INSA Rouen Normandie, CNRS, PBS UMR 6270, 76000 Rouen, France
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5
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Hosseini A, Alipour A, Baradaran Rahimi V, Askari VR. A comprehensive and mechanistic review on protective effects of kaempferol against natural and chemical toxins: Role of NF-κB inhibition and Nrf2 activation. Biofactors 2022; 49:322-350. [PMID: 36471898 DOI: 10.1002/biof.1923] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022]
Abstract
Different toxins, including chemicals and natural, can be entered from various routes and influence human health. Herbal medicines and their active components can attenuate the toxicity of agents via multiple mechanisms. For example, kaempferol, as a flavonoid, can be found in fruits and vegetables, and has an essential role in improving disorders such as cardiovascular disorders, neurological diseases, cancer, pain, and inflammation situations. The beneficial effects of kaempferol may be related to the inhibition of oxidative stress, attenuation of inflammatory factors such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), cyclooxygenase-2 (COX-2) and nuclear factor ĸB (NF-ĸB) as well as the modulation of apoptosis and mitogen-activated protein kinase (MAPK) signaling pathways. This flavonoid boasts a wide spectrum of toxin targeting effects in tissue fibrosis, inflammation, and oxidative stress thus shows promising protective effects against natural and chemical toxin induced hepatotoxicity, nephrotoxicity, cardiotoxicity, neurotoxicity, lung, and intestinal in the in vitro and in vivo setting. The most remarkable aspect of kaempferol is that it does not focus its efforts on just one organ or one molecular pathway. Although its significance as a treatment option remains questionable and requires more clinical studies, it seems to be a low-risk therapeutic option. It is crucial to emphasize that kaempferol's poor bioavailability is a significant barrier to its use as a therapeutic option. Nanotechnology can be a promising way to overcome this challenge, reviving optimism in using kaempferol as a viable treatment agent against toxin-induced disorders.
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Affiliation(s)
- Azar Hosseini
- Pharmacological Research Centre of Medicinal Plants, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Alieh Alipour
- Pharmacological Research Centre of Medicinal Plants, Mashhad University of Medical Sciences, Mashhad, Iran
- International UNESCO Center for Health-Related Basic Sciences and Human Nutrition, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Vafa Baradaran Rahimi
- Department of Cardiovascular Diseases, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Vahid Reza Askari
- International UNESCO Center for Health-Related Basic Sciences and Human Nutrition, Mashhad University of Medical Sciences, Mashhad, Iran
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
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6
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Han X, Ortines R, Mukherjee I, Kanipakala T, Kort T, Sherchand SP, Liao G, Mednikov M, Chenine AL, Aman MJ, Nykiforuk CL, Adhikari RP. Hyperimmune Targeting Staphylococcal Toxins Effectively Protect Against USA 300 MRSA Infection in Mouse Bacteremia and Pneumonia Models. Front Immunol 2022; 13:893921. [PMID: 35655774 PMCID: PMC9152286 DOI: 10.3389/fimmu.2022.893921] [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: 03/11/2022] [Accepted: 04/07/2022] [Indexed: 11/13/2022] Open
Abstract
Staphylococcus aureus has been acquiring multiple drug resistance and has evolved into superbugs such as Methicillin/Vancomycin-resistant S. aureus (MRSA/VRSA) and, consequently, is a major cause of nosocomial and community infections associated with high morbidity and mortality for which no FDA-approved vaccines or biotherapeutics are available. Previous efforts targeting the surface-associated antigens have failed in clinical testing. Here, we generated hyperimmune products from sera in rabbits against six major S. aureus toxins targeted by an experimental vaccine (IBT-V02) and demonstrated significant efficacy for an anti-virulence passive immunization strategy. Extensive in vitro binding and neutralizing titers were analyzed against six extracellular toxins from individual animal sera. All IBT-V02 immunized animals elicited the maximum immune response upon the first boost dose against all pore-forming vaccine components, while for superantigen (SAgs) components of the vaccine, second and third doses of a boost were needed to reach a plateau in binding and toxin neutralizing titers. Importantly, both anti-staphylococcus hyperimmune products consisting of full-length IgG (IBT-V02-IgG) purified from the pooled sera and de-speciated F(ab')2 (IBT-V02-F(ab')2) retained the binding and neutralizing titers against IBT-V02 target toxins. F(ab')2 also exhibited cross-neutralization titers against three leukotoxins (HlgAB, HlgCB, and LukED) and four SAgs (SEC1, SED, SEK, and SEQ) which were not part of IBT-V02. F(ab')2 also neutralized toxins in bacterial culture supernatant from major clinical strains of S. aureus. In vivo efficacy data generated in bacteremia and pneumonia models using USA300 S. aureus strain demonstrated dose-dependent protection by F(ab')2. These efficacy data confirmed the staphylococcal toxins as viable targets and support the further development effort of hyperimmune products as a potential adjunctive therapy for emergency uses against life-threatening S. aureus infections.
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Affiliation(s)
- Xiaobing Han
- Research and Development, Emergent BioSolutions Canada Inc., Winnipeg, MB, Canada.,Department of Immunology, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB, Canada
| | - Roger Ortines
- Integrated Biotherapeutics Inc. (IBT), Rockville, MD, United States
| | - Ipsita Mukherjee
- Integrated Biotherapeutics Inc. (IBT), Rockville, MD, United States
| | | | - Thomas Kort
- Integrated Biotherapeutics Inc. (IBT), Rockville, MD, United States
| | | | - Grant Liao
- Integrated Biotherapeutics Inc. (IBT), Rockville, MD, United States
| | - Mark Mednikov
- Integrated Biotherapeutics Inc. (IBT), Rockville, MD, United States
| | - Agnes L Chenine
- Integrated Biotherapeutics Inc. (IBT), Rockville, MD, United States
| | - M Javad Aman
- Integrated Biotherapeutics Inc. (IBT), Rockville, MD, United States
| | - Cory L Nykiforuk
- Research and Development, Emergent BioSolutions Canada Inc., Winnipeg, MB, Canada
| | - Rajan P Adhikari
- Integrated Biotherapeutics Inc. (IBT), Rockville, MD, United States
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7
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Expression of Staphylococcal Virulence Genes In Situ in Human Skin and Soft Tissue Infections. Antibiotics (Basel) 2022; 11:antibiotics11040527. [PMID: 35453277 PMCID: PMC9032627 DOI: 10.3390/antibiotics11040527] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/08/2022] [Accepted: 04/10/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Staphylococcus aureus, the most common pathogen in skin and soft tissue infections (SSTI), harbors many well-characterized virulence genes. However, the expression of many of them in SSTIs is unknown. In this study, S. aureus virulence genes expressed in SSTI were investigated. Methods: Fifty-three subjects presenting to the outpatient’s care and emergency departments with a purulent SSTI at two medical centers in Wisconsin, USA, were enrolled in the study. Total mRNA was extracted from the purulent or swab materials, made into cDNA and sequenced on MiSeq platform. The relative cDNA counts to gmk and identifications of the transcripts were carried out with respect to USA300 reference genome and using SAMTOOLS v.1.3 and BWA, respectively. Result: A significantly higher cDNA count was observed for many of the virulence and regulatory gene transcripts in the pus samples compared to the swab samples relative to the cDNA counts for gmk, a housekeeping gene. They were for lukS-PV (18.6 vs. 14.2), isaA (13.4 vs. 8.5), ssaA (4.8 vs. 3.1), hlgC (1.4 vs. 1.33), atl (17.7 vs. 8.33), clfA (3.9 vs. 0.83), eno (6.04 vs. 3.16), fnbA (5.93 vs. 0.33), saeS (6.3 vs. 1.33), saeR (5.4 vs. 3.33) and agrC (5.6 vs. 1.5). Conclusions: A relative increase in the transcripts of several toxins, adhesion and regulatory genes with respect to a gmk in purulent materials suggests their role in situ during SSTIs, perhaps in an orchestrated manner.
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Wong Fok Lung T, Chan LC, Prince A, Yeaman MR, Archer NK, Aman MJ, Proctor RA. Staphylococcus aureus adaptive evolution: Recent insights on how immune evasion, immunometabolic subversion and host genetics impact vaccine development. Front Cell Infect Microbiol 2022; 12:1060810. [PMID: 36636720 PMCID: PMC9831658 DOI: 10.3389/fcimb.2022.1060810] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 11/16/2022] [Indexed: 12/28/2022] Open
Abstract
Despite meritorious attempts, a S. aureus vaccine that prevents infection or mitigates severity has not yet achieved efficacy endpoints in prospective, randomized clinical trials. This experience underscores the complexity of host-S. aureus interactions, which appear to be greater than many other bacterial pathogens against which successful vaccines have been developed. It is increasingly evident that S. aureus employs strategic countermeasures to evade or exploit human immune responses. From entering host cells to persist in stealthy intracellular reservoirs, to sensing the environmental milieu and leveraging bacterial or host metabolic products to reprogram host immune responses, S. aureus poses considerable challenges for the development of effective vaccines. The fact that this pathogen causes distinct types of infections and can undergo transient genetic, transcriptional or metabolic adaptations in vivo that do not occur in vitro compounds challenges in vaccine development. Notably, the metabolic versatility of both bacterial and host immune cells as they compete for available substrates within specific tissues inevitably impacts the variable repertoire of gene products that may or may not be vaccine antigens. In this respect, S. aureus has chameleon phenotypes that have alluded vaccine strategies thus far. Nonetheless, a number of recent studies have also revealed important new insights into pathogenesis vulnerabilities of S. aureus. A more detailed understanding of host protective immune defenses versus S. aureus adaptive immune evasion mechanisms may offer breakthroughs in the development of effective vaccines, but at present this goal remains a very high bar. Coupled with the recent advances in human genetics and epigenetics, newer vaccine technologies may enable such a goal. If so, future vaccines that protect against or mitigate the severity of S. aureus infections are likely to emerge at the intersection of precision and personalized medicine. For now, the development of S. aureus vaccines or alternative therapies that reduce mortality and morbidity must continue to be pursued.
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Affiliation(s)
| | - Liana C Chan
- Department of Medicine, David Geffen School of Medicine at University of California Loss Angeles (UCLA), Los Angeles, CA, United States.,Divisions of Molecular Medicine and Infectious Diseases, Harbor-University of California Loss Angeles (UCLA) Medical Center, Torrance, CA, United States.,Lundquist Institute for Biomedical Innovation at Harbor-University of California Loss Angeles (UCLA) Medical Center, Torrance, CA, United States
| | - Alice Prince
- Department of Pediatrics, Columbia University, New York, NY, United States
| | - Michael R Yeaman
- Department of Medicine, David Geffen School of Medicine at University of California Loss Angeles (UCLA), Los Angeles, CA, United States.,Divisions of Molecular Medicine and Infectious Diseases, Harbor-University of California Loss Angeles (UCLA) Medical Center, Torrance, CA, United States.,Lundquist Institute for Biomedical Innovation at Harbor-University of California Loss Angeles (UCLA) Medical Center, Torrance, CA, United States
| | - Nathan K Archer
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - M Javad Aman
- Integrated BioTherapeutics, Rockville, MD, United States
| | - Richard A Proctor
- Department of Medicine and Medical Microbiology/Immunology, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
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9
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Kailasan S, Kant R, Noonan-Shueh M, Kanipakala T, Liao G, Shulenin S, Leung DW, Alm RA, Adhikari RP, Amarasinghe GK, Gross ML, Aman MJ. Antigenic landscapes on Staphylococcus aureus pore-forming toxins reveal insights into specificity and cross-neutralization. MAbs 2022; 14:2083467. [PMID: 35730685 PMCID: PMC9225675 DOI: 10.1080/19420862.2022.2083467] [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] [Indexed: 11/29/2022] Open
Abstract
Staphylococcus aureus carries an exceptional repertoire of virulence factors that aid in immune evasion. Previous single-target approaches for S. aureus-specific vaccines and monoclonal antibodies (mAbs) have failed in clinical trials due to the multitude of virulence factors released during infection. Emergence of antibiotic-resistant strains demands a multi-target approach involving neutralization of different, non-overlapping pathogenic factors. Of the several pore-forming toxins that contribute to S. aureus pathogenesis, efforts have largely focused on mAbs that neutralize α-hemolysin (Hla) and target the receptor-binding site. Here, we isolated two anti-Hla and three anti-Panton-Valentine Leukocidin (LukSF-PV) mAbs, and used a combination of hydrogen deuterium exchange mass spectrometry (HDX-MS) and alanine scanning mutagenesis to delineate and validate the toxins’ epitope landscape. Our studies identified two novel, neutralizing epitopes targeted by 2B6 and CAN6 on Hla that provided protection from hemolytic activity in vitro and showed synergy in rodent pneumonia model against lethal challenge. Of the anti-LukF mAbs, SA02 and SA131 showed specific neutralization activity to LukSF-PV while SA185 showed cross-neutralization activity to LukSF-PV, γ-hemolysin HlgAB, and leukotoxin ED. We further compared these antigen-specific mAbs to two broadly neutralizing mAbs, H5 (targets Hla, LukSF-PV, HlgAB, HlgCB, and LukED) and SA185 (targeting LukSF-PV, HlgAB, and LukED), and identified molecular level markers for broad-spectrum reactivity among the pore-forming toxins by HDX-MS. To further underscore the need to target the cross-reactive epitopes on leukocidins for the development of broad-spectrum therapies, we annotated Hla sequences isolated from patients in multiple countries for genomic variations within the perspective of our defined epitopes.
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Affiliation(s)
| | - Ravi Kant
- Department of Chemistry, Washington University in St. Louis, St. Louis, USA
| | | | | | - Grant Liao
- Integrated BioTherapeutics, Rockville, USA
| | | | - Daisy W Leung
- Department of Medicine, Washington University in St. Louis, St. Louis, USA
| | - Richard A Alm
- Boston University School of Law, Boston University, Boston, USA
| | | | - Gaya K Amarasinghe
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, USA
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, USA
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10
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Yin N, Yang X, Wang L, Zhang C, Guan J, Tao Y, Guo X, Zhao Y, Song W, Wang B, Tang Y. Kaempferol inhibits the expression of α-hemolysin and protects mice from methicillin-resistant Staphylococcus aureus-induced lethal pneumonia. Microb Pathog 2021; 162:105336. [PMID: 34856361 DOI: 10.1016/j.micpath.2021.105336] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 11/27/2021] [Accepted: 11/27/2021] [Indexed: 01/15/2023]
Abstract
Staphylococcus aureus (S. aureus) is a common pathogenic bacterium that induces a variety of diseases in humans and animals. The significant pathogenicity of S. aureus is due to its expression of several virulence factors. Alpha-hemolysin (Hla) has attracted attention as a virulence factor in staphylococcal pathogenesis and has been the predominant focus of intense research. In this study, we found that kaempferol, a flavonoid compound, inhibited hemolysis at a low concentration (32 μg/mL) and exerted no effect on bacterial growth. Western blot and RT-qPCR assays further demonstrated that kaempferol downregulated the expression of Hla in S. aureus. We observed that kaempferol alleviated the damage from S. aureus Hla in A549 cells. More importantly, kaempferol showed a potent protective effect on mice pneumonia induced by MRSA, as evidenced by a significant improvement in the survival of mice, a reduction in the number of colonized colonies in lung tissue and a decrease in the pathological damage to lung tissues. In summary, the results demonstrate the protective effect of kaempferol on MRSA-induced lethal pneumonia in mice and indicate that kaempferol could be developed as a potential anti-MRSA drug.
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Affiliation(s)
- Ning Yin
- Changchun University of Chinese Medicine, Changchun, 130117, China
| | - Xin Yang
- MOE Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing, 210096, China; Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, 271016, China
| | - Li Wang
- Changchun University of Chinese Medicine, Changchun, 130117, China
| | - Chi Zhang
- Changchun University of Chinese Medicine, Changchun, 130117, China
| | - Jiyu Guan
- Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Ye Tao
- Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, 130021, China
| | - Xuerui Guo
- Changchun University of Chinese Medicine, Changchun, 130117, China; School of Pharmacy, Jilin University, Changchun, 130021, China
| | - Yicheng Zhao
- Changchun University of Chinese Medicine, Changchun, 130117, China
| | - Wu Song
- Changchun University of Chinese Medicine, Changchun, 130117, China.
| | - Bingmei Wang
- Changchun University of Chinese Medicine, Changchun, 130117, China.
| | - Yong Tang
- Changchun University of Chinese Medicine, Changchun, 130117, China.
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11
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Karauzum H, Venkatasubramaniam A, Adhikari RP, Kort T, Holtsberg FW, Mukherjee I, Mednikov M, Ortines R, Nguyen NTQ, Doan TMN, Diep BA, Lee JC, Aman MJ. IBT-V02: A Multicomponent Toxoid Vaccine Protects Against Primary and Secondary Skin Infections Caused by Staphylococcus aureus. Front Immunol 2021; 12:624310. [PMID: 33777005 PMCID: PMC7987673 DOI: 10.3389/fimmu.2021.624310] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 02/08/2021] [Indexed: 12/12/2022] Open
Abstract
Staphylococcus aureus causes a wide range of diseases from skin infections to life threatening invasive diseases such as bacteremia, endocarditis, pneumonia, surgical site infections, and osteomyelitis. Skin infections such as furuncles, carbuncles, folliculitis, erysipelas, and cellulitis constitute a large majority of infections caused by S. aureus (SA). These infections cause significant morbidity, healthcare costs, and represent a breeding ground for antimicrobial resistance. Furthermore, skin infection with SA is a major risk factor for invasive disease. Here we describe the pre-clinical efficacy of a multicomponent toxoid vaccine (IBT-V02) for prevention of S. aureus acute skin infections and recurrence. IBT-V02 targets six SA toxins including the pore-forming toxins alpha hemolysin (Hla), Panton-Valentine leukocidin (PVL), leukocidin AB (LukAB), and the superantigens toxic shock syndrome toxin-1 and staphylococcal enterotoxins A and B. Immunization of mice and rabbits with IBT-V02 generated antibodies with strong neutralizing activity against toxins included in the vaccine, as well as cross-neutralizing activity against multiple related toxins, and protected against skin infections by several clinically relevant SA strains of USA100, USA300, and USA1000 clones. Efficacy of the vaccine was also shown in non-naïve mice pre-exposed to S. aureus. Furthermore, vaccination with IBT-V02 not only protected mice from a primary infection but also demonstrated lasting efficacy against a secondary infection, while prior challenge with the bacteria alone was unable to protect against recurrence. Serum transfer studies in a primary infection model showed that antibodies are primarily responsible for the protective response.
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Affiliation(s)
| | | | | | - Tom Kort
- Integrated BioTherapeutics, Rockville, MD, United States
| | | | | | - Mark Mednikov
- Integrated BioTherapeutics, Rockville, MD, United States
| | - Roger Ortines
- Integrated BioTherapeutics, Rockville, MD, United States
| | - Nhu T. Q. Nguyen
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Thien M. N. Doan
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Binh An Diep
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Jean C. Lee
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States
| | - M. Javad Aman
- Integrated BioTherapeutics, Rockville, MD, United States
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12
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Venkatasubramaniam A, Liao G, Cho E, Adhikari RP, Kort T, Holtsberg FW, Elsass KE, Kobs DJ, Rudge TL, Kauffman KD, Lora NE, Barber DL, Aman MJ, Karauzum H. Safety and Immunogenicity of a 4-Component Toxoid-Based Staphylococcus aureus Vaccine in Rhesus Macaques. Front Immunol 2021; 12:621754. [PMID: 33717122 PMCID: PMC7947289 DOI: 10.3389/fimmu.2021.621754] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 01/19/2021] [Indexed: 12/17/2022] Open
Abstract
Staphylococcus aureus is a leading cause of significant morbidity and mortality and an enormous economic burden to public health worldwide. Infections caused by methicillin-resistant S. aureus (MRSA) pose a major threat as MRSA strains are becoming increasingly prevalent and multi-drug resistant. To this date, vaccines targeting surface-bound antigens demonstrated promising results in preclinical testing but have failed in clinical trials. S. aureus pathogenesis is in large part driven by immune destructive and immune modulating toxins and thus represent promising vaccine targets. Hence, the objective of this study was to evaluate the safety and immunogenicity of a staphylococcal 4-component vaccine targeting secreted bi-component pore-forming toxins (BCPFTs) and superantigens (SAgs) in non-human primates (NHPs). The 4-component vaccine proved to be safe, even when repeated vaccinations were given at a dose that is 5 to 10- fold higher than the proposed human dose. Vaccinated rhesus macaques did not exhibit clinical signs, weight loss, or changes in hematology or serum chemistry parameters related to the administration of the vaccine. No acute, vaccine-related elevation of serum cytokine levels was observed after vaccine administration, confirming the toxoid components lacked superantigenicity. Immunized animals demonstrated high level of toxin-specific total and neutralizing antibodies toward target antigens of the 4-component vaccine as well as cross-neutralizing activity toward staphylococcal BCPFTs and SAgs that are not direct targets of the vaccine. Cross-neutralization was also observed toward the heterologous streptococcal pyogenic exotoxin B. Ex vivo stimulation of PBMCs with individual vaccine components demonstrated an overall increase in several T cell cytokines measured in supernatants. Immunophenotyping of CD4 T cells ex vivo showed an increase in Ag-specific polyfunctional CD4 T cells in response to antigen stimulation. Taken together, we demonstrate that the 4-component vaccine is well-tolerated and immunogenic in NHPs generating both humoral and cellular immune responses. Targeting secreted toxin antigens could be the next-generation vaccine approach for staphylococcal vaccines if also proven to provide efficacy in humans.
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Affiliation(s)
| | - Grant Liao
- Integrated BioTherapeutics, Rockville, MD, United States
| | - Eunice Cho
- Integrated BioTherapeutics, Rockville, MD, United States
| | | | - Tom Kort
- Integrated BioTherapeutics, Rockville, MD, United States
| | | | | | - Dean J. Kobs
- Batelle - West Jefferson, West Jefferson, OH, United States
| | | | - Keith D. Kauffman
- Laboratory of Parasitic Diseases, T Lymphocyte Biology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Nickiana E. Lora
- Laboratory of Parasitic Diseases, T Lymphocyte Biology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Daniel L. Barber
- Laboratory of Parasitic Diseases, T Lymphocyte Biology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - M. Javad Aman
- Integrated BioTherapeutics, Rockville, MD, United States
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13
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Mourenza Á, Gil JA, Mateos LM, Letek M. Alternative Anti-Infective Treatments to Traditional Antibiotherapy against Staphylococcal Veterinary Pathogens. Antibiotics (Basel) 2020; 9:antibiotics9100702. [PMID: 33076497 PMCID: PMC7602553 DOI: 10.3390/antibiotics9100702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/13/2020] [Accepted: 10/14/2020] [Indexed: 12/29/2022] Open
Abstract
The genus Staphylococcus encompasses many species that may be pathogenic to both humans and farm animals. These bacteria have the potential to acquire multiple resistant traits to the antimicrobials currently used in the veterinary or medical settings. These pathogens may commonly cause zoonoses, and the infections they cause are becoming difficult to treat due to antimicrobial resistance. Therefore, the development of novel alternative treatments to traditional antibiotherapy has gained interest in recent years. Here, we reviewed the most promising therapeutic strategies developed to control staphylococcal infections in the veterinary field to overcome antibiotic resistance.
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Affiliation(s)
- Álvaro Mourenza
- Departamento de Biología Molecular, Área de Microbiología, Universidad de León, 24071 León, Spain; (Á.M.); (J.A.G.)
| | - José A. Gil
- Departamento de Biología Molecular, Área de Microbiología, Universidad de León, 24071 León, Spain; (Á.M.); (J.A.G.)
- Instituto de Biología Molecular, Genómica y Proteómica (INBIOMIC), Universidad de León, 24071 León, Spain
| | - Luis M. Mateos
- Departamento de Biología Molecular, Área de Microbiología, Universidad de León, 24071 León, Spain; (Á.M.); (J.A.G.)
- Instituto de Biología Molecular, Genómica y Proteómica (INBIOMIC), Universidad de León, 24071 León, Spain
- Correspondence: (L.M.M.); (M.L.)
| | - Michal Letek
- Departamento de Biología Molecular, Área de Microbiología, Universidad de León, 24071 León, Spain; (Á.M.); (J.A.G.)
- Instituto de Desarrollo Ganadero y Sanidad Animal (INDEGSAL), Universidad de León, 24071 León, Spain
- Correspondence: (L.M.M.); (M.L.)
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14
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Tran VG, Venkatasubramaniam A, Adhikari RP, Krishnan S, Wang X, Le VTM, Le HN, Vu TTT, Schneider-Smith E, Aman MJ, Diep BA. Efficacy of Active Immunization With Attenuated α-Hemolysin and Panton-Valentine Leukocidin in a Rabbit Model of Staphylococcus aureus Necrotizing Pneumonia. J Infect Dis 2020; 221:267-275. [PMID: 31504652 DOI: 10.1093/infdis/jiz437] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 08/21/2019] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus is a common pathogen causing infections in humans with various degrees of severity, with pneumonia being one of the most severe infections. In as much as staphylococcal pneumonia is a disease driven in large part by α-hemolysin (Hla) and Panton-Valentine leukocidin (PVL), we evaluated whether active immunization with attenuated forms of Hla (HlaH35L/H48L) alone, PVL components (LukS-PVT28F/K97A/S209A and LukF-PVK102A) alone, or combination of all 3 toxoids could prevent lethal challenge in a rabbit model of necrotizing pneumonia caused by the USA300 community-associated methicillin-resistant S. aureus (MRSA). Rabbits vaccinated with Hla toxoid alone or PVL components alone were only partially protected against lethal pneumonia, whereas those vaccinated with all 3 toxoids had 100% protection against lethality. Vaccine-mediated protection correlated with induction of polyclonal antibody response that neutralized not only α-hemolysin and PVL, but also other related toxins, produced by USA300 and other epidemic MRSA clones.
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Affiliation(s)
- Vuvi G Tran
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, University of California, San Francisco
| | | | | | | | - Xing Wang
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, University of California, San Francisco
| | - Vien T M Le
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, University of California, San Francisco
| | - Hoan N Le
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, University of California, San Francisco
| | - Trang T T Vu
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, University of California, San Francisco
| | - Erika Schneider-Smith
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, University of California, San Francisco
| | - M Javad Aman
- Integrated Biotherapeutics, Inc, Rockville, Maryland
| | - Binh An Diep
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, University of California, San Francisco
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15
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Miller LS, Fowler VG, Shukla SK, Rose WE, Proctor RA. Development of a vaccine against Staphylococcus aureus invasive infections: Evidence based on human immunity, genetics and bacterial evasion mechanisms. FEMS Microbiol Rev 2020; 44:123-153. [PMID: 31841134 PMCID: PMC7053580 DOI: 10.1093/femsre/fuz030] [Citation(s) in RCA: 144] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 12/13/2019] [Indexed: 12/12/2022] Open
Abstract
Invasive Staphylococcus aureus infections are a leading cause of morbidity and mortality in both hospital and community settings, especially with the widespread emergence of virulent and multi-drug resistant methicillin-resistant S. aureus strains. There is an urgent and unmet clinical need for non-antibiotic immune-based approaches to treat these infections as the increasing antibiotic resistance is creating a serious threat to public health. However, all vaccination attempts aimed at preventing S. aureus invasive infections have failed in human trials, especially all vaccines aimed at generating high titers of opsonic antibodies against S. aureus surface antigens to facilitate antibody-mediated bacterial clearance. In this review, we summarize the data from humans regarding the immune responses that protect against invasive S. aureus infections as well as host genetic factors and bacterial evasion mechanisms, which are important to consider for the future development of effective and successful vaccines and immunotherapies against invasive S. aureus infections in humans. The evidence presented form the basis for a hypothesis that staphylococcal toxins (including superantigens and pore-forming toxins) are important virulence factors, and targeting the neutralization of these toxins are more likely to provide a therapeutic benefit in contrast to prior vaccine attempts to generate antibodies to facilitate opsonophagocytosis.
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Affiliation(s)
- Lloyd S Miller
- Immunology, Janssen Research and Development, 1400 McKean Road, Spring House, PA, 19477, USA.,Department of Dermatology, Johns Hopkins University School of Medicine, 1550 Orleans Street, Cancer Research Building 2, Suite 209, Baltimore, MD, 21231, USA.,Department of Medicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine, 1830 East Monument Street, Baltimore, MD, 21287, USA.,Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, 601 North Caroline Street, Baltimore, MD, 21287, USA.,Department of Materials Science and Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD, 21218, USA
| | - Vance G Fowler
- Department of Medicine, Division of Infectious Diseases, Duke University Medical Center, 315 Trent Drive, Hanes House, Durham, NC, 27710, USA.,Duke Clinical Research Institute, Duke University Medical Center, 40 Duke Medicine Circle, Durham, NC, 27710, USA
| | - Sanjay K Shukla
- Center for Precision Medicine Research, Marshfield Clinic Research Institute, 1000 North Oak Avenue, Marshfield, WI, 54449, USA.,Computation and Informatics in Biology and Medicine, University of Wisconsin, 425 Henry Mall, Room 3445, Madison, WI, 53706, USA
| | - Warren E Rose
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, 1685 Highland Avenue, 5158 Medical Foundation Centennial Building, Madison, WI, 53705, USA.,Pharmacy Practice Division, University of Wisconsin-Madison, 777 Highland Avenue, 4123 Rennebohm Hall, Madison, WI, 53705 USA
| | - Richard A Proctor
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, 1685 Highland Avenue, 5158 Medical Foundation Centennial Building, Madison, WI, 53705, USA.,Department of Medical Microbiology and Immunology, University of Wisconsin-Madison School of Medicine and Public Health, 1550 Linden Drive, Microbial Sciences Building, Room 1334, Madison, WI, 53705, USA
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16
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Rational Design of Toxoid Vaccine Candidates for Staphylococcus aureus Leukocidin AB (LukAB). Toxins (Basel) 2019; 11:toxins11060339. [PMID: 31207937 PMCID: PMC6628420 DOI: 10.3390/toxins11060339] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/10/2019] [Accepted: 06/12/2019] [Indexed: 11/16/2022] Open
Abstract
Staphylococcus aureus (SA) infections cause high mortality and morbidity in humans. Being central to its pathogenesis, S. aureus thwarts the host defense by secreting a myriad of virulence factors, including bicomponent, pore-forming leukotoxins. While all vaccine development efforts that aimed at achieving opsonophagocytic killing have failed, targeting virulence by toxoid vaccines represents a novel approach to preventing mortality and morbidity that are caused by SA. The recently discovered leukotoxin LukAB kills human phagocytes and monocytes and it is present in all known S. aureus clinical isolates. While using a structure-guided approach, we generated a library of mutations that targeted functional domains within the LukAB heterodimer to identify attenuated toxoids as potential vaccine candidates. The mutants were evaluated based on expression, solubility, yield, biophysical properties, cytotoxicity, and immunogenicity, and several fully attenuated LukAB toxoids that were capable of eliciting high neutralizing antibody titers were identified. Rabbit polyclonal antibodies against the lead toxoid candidate provided potent neutralization of LukAB. While the neutralization of LukAB alone was not sufficient to fully suppress leukotoxicity in supernatants of S. aureus USA300 isolates, a combination of antibodies against LukAB, α-toxin, and Panton-Valentine leukocidin completely neutralized the cytotoxicity of these strains. These data strongly support the inclusion of LukAB toxoids in a multivalent toxoid vaccine for the prevention of S. aureus disease.
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17
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Liu Q, Mazhar M, Miller LS. Immune and Inflammatory Reponses to Staphylococcus aureus Skin Infections. CURRENT DERMATOLOGY REPORTS 2018; 7:338-349. [PMID: 30989002 DOI: 10.1007/s13671-018-0235-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Purpose of Review There have been recent advances in our understanding of cutaneous immune responses to the important human skin pathogen, Staphylococcus aureus (S. aureus). This review will highlight these insights into innate and adaptive immune mechanisms in host defense and cutaneous inflammation in response to S. aureus skin infections. Recent Findings Antimicrobial peptides, pattern recognition receptors and inflammasome activation function in innate immunity as well as T cells and their effector cytokines play a key role in adaptive immunity against S. aureus skin infections. In addition, certain mechanisms by which S. aureus contributes to aberrant cutaneous inflammation, such as in flares of the inflammatory skin disease atopic dermatitis have also been identified. Summary These cutaneous immune mechanisms could provide new targets for future vaccines and immune-based therapies to combat skin infections and cutaneous inflammation caused by S. aureus.
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Affiliation(s)
- Qi Liu
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Momina Mazhar
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Lloyd S Miller
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
- Department of Medicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
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18
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Venkatasubramaniam A, Kanipakala T, Ganjbaksh N, Mehr R, Mukherjee I, Krishnan S, Bae T, Aman MJ, Adhikari RP. A Critical Role for HlgA in Staphylococcus aureus Pathogenesis Revealed by A Switch in the SaeRS Two-Component Regulatory System. Toxins (Basel) 2018; 10:E377. [PMID: 30231498 PMCID: PMC6162840 DOI: 10.3390/toxins10090377] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 09/11/2018] [Accepted: 09/11/2018] [Indexed: 12/18/2022] Open
Abstract
Cytolytic pore-forming toxins including alpha hemolysin (Hla) and bicomponent leukotoxins play an important role in the pathogenesis of Staphylococcus aureus. These toxins kill the polymorphonuclear phagocytes (PMNs), disrupt epithelial and endothelial barriers, and lyse erythrocytes to provide iron for bacterial growth. The expression of these toxins is regulated by the two-component sensing systems Sae and Agr. Here, we report that a point mutation (L18P) in SaeS, the histidine kinase sensor of the Sae system, renders the S. aureus Newman hemolytic activity fully independent of Hla and drastically increases the PMN lytic activity. Furthermore, this Hla-independent activity, unlike Hla itself, can lyse human erythrocytes. The Hla-independent activity towards human erythrocytes was also evident in USA300, however, under strict agr control. Gene knockout studies revealed that this Hla-independent Sae-regulated activity was entirely dependent on gamma hemolysin A subunit (HlgA). In contrast, hemolytic activity of Newman towards human erythrocytes from HlgAB resistant donors was completely dependent on agr. The culture supernatant from Newman S. aureus could be neutralized by antisera against two vaccine candidates based on LukS and LukF subunits of Panton-Valentine leukocidin but not by an anti-Hla neutralizing antibody. These findings display the complex involvement of Sae and Agr systems in regulating the virulence of S. aureus and have important implications for vaccine and immunotherapeutics development for S. aureus disease in humans.
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Affiliation(s)
| | | | | | - Rana Mehr
- Integrated Biotherapeutics Inc., Rockville, MD 20850, USA.
| | | | | | - Taeok Bae
- Department of Microbiology and Immunology, Indiana University School of Medicine-Northwest, Gary, IN 46408, USA.
| | - M Javad Aman
- Integrated Biotherapeutics Inc., Rockville, MD 20850, USA.
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19
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Pahal V. Quercetin, a secondary metabolite present in methanolic extract of Calendula officinalis, is a potent inhibitor of peptide deformylase, undecaprenyl pyrophosphate synthase and DNA primase enzymes of Staphylococcus aureus: an in vitro and in silico result analysis. ACTA ACUST UNITED AC 2018. [DOI: 10.15406/mojddt.2018.02.00050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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20
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Perumal N, Dass BS, Mani S, Krishnan P. Prevalence of bi-component pore-forming toxin genotypes of Staphylococcus aureus causing skin and soft tissue infections. Indian J Med Microbiol 2018; 35:146-147. [PMID: 28303840 DOI: 10.4103/ijmm.ijmm_16_424] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Nagaraj Perumal
- Department of Microbiology, Dr. ALM PG Institute of Basic Medical Sciences, University of Madras, Chennai, India
| | - Betsy Sowndarya Dass
- Department of Microbiology, Dr. ALM PG Institute of Basic Medical Sciences, University of Madras, Chennai, India
| | - Stalin Mani
- Department of Microbiology, Government Dharmapuri Medical College, Dharmapuri, Tamil Nadu, India
| | - Padma Krishnan
- Department of Microbiology, Dr. ALM PG Institute of Basic Medical Sciences, University of Madras, Chennai, India
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21
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Genetics of bi-component leukocidin and drug resistance in nasal and clinical Staphylococcus aureus in Lagos, Nigeria. Microb Pathog 2017; 115:1-7. [PMID: 29246634 DOI: 10.1016/j.micpath.2017.12.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 12/09/2017] [Accepted: 12/09/2017] [Indexed: 11/20/2022]
Abstract
BACKGROUND Resistant and virulent Staphylococcus aureus is a global public health challenge. Staphylococcal Bi-component leukotoxins are cytolytic to immune cells and evolve to disarm the innate immunity during infections, hence the severity of the disease. OBJECTIVE We studied drug resistance profile and the occurrence of bi-component leukocidin in clinical and nasal S. aureus in Lagos, Nigeria. METHOD Ninety-two S. aureus (70 clinical and 22 nasal) strains were characterized by conventional and molecular methods. RESULT Of the resistance profiles generated, no isolate was resistant to fosfomycin, fusidic acid, teicoplanin, vancomycin, linezolid, mupirocin, nitrofurantoin and tigecycline. Twelve MRSA carrying staphylococcal cassette chromosome mecA gene types I, III, and IV elements were identified only in the clinical samples and type I dominated. High rates of lukE/D (100% among MRSA) and lukPV (dominated MSSA) were recorded among the nasal and clinical isolates. Staphylococcus aureus harboring only lukE/D (from clinical & colonizing MSSA) and combined lukE/D and lukPV (mostly from clinical MSSA, colonizing MSSA and clinical MRSA) toxins were found. CONCLUSION Although, mecA resistant genes were found only among clinical MRSA, the occurrence of other bi-component leukocidin genes in a large proportion among the isolates from both community and clinical settings is a major concern. The need for effective resistance and virulence factor surveillance, re-enforcement of antibiotic stewardship and good infection control policy, to prevent dissemination of epidemic strains is highlighted.
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22
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Melo MCDA, Rodrigues CG, Pol-Fachin L. Staphylococcus aureus δ-toxin in aqueous solution: Behavior in monomeric and multimeric states. Biophys Chem 2017; 227:21-28. [DOI: 10.1016/j.bpc.2017.05.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 05/15/2017] [Accepted: 05/24/2017] [Indexed: 01/01/2023]
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23
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El-Aouar Filho RA, Nicolas A, De Paula Castro TL, Deplanche M, De Carvalho Azevedo VA, Goossens PL, Taieb F, Lina G, Le Loir Y, Berkova N. Heterogeneous Family of Cyclomodulins: Smart Weapons That Allow Bacteria to Hijack the Eukaryotic Cell Cycle and Promote Infections. Front Cell Infect Microbiol 2017; 7:208. [PMID: 28589102 PMCID: PMC5440457 DOI: 10.3389/fcimb.2017.00208] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 05/09/2017] [Indexed: 12/13/2022] Open
Abstract
Some bacterial pathogens modulate signaling pathways of eukaryotic cells in order to subvert the host response for their own benefit, leading to successful colonization and invasion. Pathogenic bacteria produce multiple compounds that generate favorable conditions to their survival and growth during infection in eukaryotic hosts. Many bacterial toxins can alter the cell cycle progression of host cells, impairing essential cellular functions and impeding host cell division. This review summarizes current knowledge regarding cyclomodulins, a heterogeneous family of bacterial effectors that induce eukaryotic cell cycle alterations. We discuss the mechanisms of actions of cyclomodulins according to their biochemical properties, providing examples of various cyclomodulins such as cycle inhibiting factor, γ-glutamyltranspeptidase, cytolethal distending toxins, shiga toxin, subtilase toxin, anthrax toxin, cholera toxin, adenylate cyclase toxins, vacuolating cytotoxin, cytotoxic necrotizing factor, Panton-Valentine leukocidin, phenol soluble modulins, and mycolactone. Special attention is paid to the benefit provided by cyclomodulins to bacteria during colonization of the host.
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Affiliation(s)
- Rachid A El-Aouar Filho
- STLO, Agrocampus Ouest Rennes, Institut National de la Recherche AgronomiqueRennes, France.,Departamento de Biologia Geral, Laboratório de Genética Celular e Molecular (LGCM), Instituto de Ciências Biológicas, Universidade Federal de Minas GeraisBelo Horizonte, Brazil
| | - Aurélie Nicolas
- STLO, Agrocampus Ouest Rennes, Institut National de la Recherche AgronomiqueRennes, France
| | - Thiago L De Paula Castro
- Departamento de Biologia Geral, Laboratório de Genética Celular e Molecular (LGCM), Instituto de Ciências Biológicas, Universidade Federal de Minas GeraisBelo Horizonte, Brazil
| | - Martine Deplanche
- STLO, Agrocampus Ouest Rennes, Institut National de la Recherche AgronomiqueRennes, France
| | - Vasco A De Carvalho Azevedo
- Departamento de Biologia Geral, Laboratório de Genética Celular e Molecular (LGCM), Instituto de Ciências Biológicas, Universidade Federal de Minas GeraisBelo Horizonte, Brazil
| | - Pierre L Goossens
- HistoPathologie et Modèles Animaux/Pathogénie des Toxi-Infections Bactériennes, Institut PasteurParis, France
| | - Frédéric Taieb
- CHU Purpan USC INRA 1360-CPTP, U1043 Institut National de la Santé et de la Recherche Médicale, Pathogénie Moléculaire et Cellulaire des Infections à Escherichia coliToulouse, France
| | - Gerard Lina
- International Center for Infectiology ResearchLyon, France.,Centre National de la Recherche Scientifique, UMR5308, Institut National de la Santé et de la Recherche Médicale U1111, Ecole Normale Supérieure de Lyon, Université Lyon 1Lyon, France.,Département de Biologie, Institut des Agents Infectieux, Hospices Civils de LyonLyon, France
| | - Yves Le Loir
- STLO, Agrocampus Ouest Rennes, Institut National de la Recherche AgronomiqueRennes, France
| | - Nadia Berkova
- STLO, Agrocampus Ouest Rennes, Institut National de la Recherche AgronomiqueRennes, France
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Wang D, Zhang L, Yong C, Shen M, Ali T, Shahid M, Han K, Zhou X, Han B. Relationships among superantigen toxin gene profiles, genotypes, and pathogenic characteristics of Staphylococcus aureus isolates from bovine mastitis. J Dairy Sci 2017; 100:4276-4286. [PMID: 28434738 DOI: 10.3168/jds.2016-12405] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 02/07/2017] [Indexed: 11/19/2022]
Abstract
Staphylococcus aureus is one of the major etiological agents of bovine mastitis, harboring a wide variety of staphylococcal superantigen (SAg) toxin genes. The SAg toxin genes are reported to be closely associated with the pathogenicity of the Staph. aureus causing the bovine mastitis. This study was conducted to investigate SAg toxin gene profiles and to assess the relationships among SAg toxin genes, genotypes of Staph. aureus, and their pathogenic properties. A total of 327 quarter milk samples were collected from bovine mastitis cases for isolation and identification of pathogens. In total, 35 isolates were identified as Staph. aureus, and the prevalence of Staph. aureus in milk samples was 13.6% (35/256). Polymerase chain reaction (PCR) and randomly amplified polymorphic DNA (RAPD) assays were used to detect the SAg toxin genes and to genotype Staph. aureus strains isolated from milk samples of bovine mastitis in 10 dairy herds located in Ningxia, China, respectively. The results showed that among the Staph. aureus isolates (n = 35), 71.4% (n = 25) of isolates carried at least one SAg toxin gene. In total, 18 SAg genes and 21 different gene combination patterns were detected among these isolates. The most common SAg genes in Staph. aureus isolates were sei, sen, and seu (44.0% each), followed by seo, tst, and etB (28.0% each), etA (24.0%), sem and sep (16.0% each), seb, sec, sed, and sek (12.0% each), and sea and seh genes (8.0% each); the seg, sej, and ser genes were present in 4.0% of the isolates. Three gene combinations were found to be related to mobile genetic elements that carried 2 or more genes. The egc-cluster of the seg-sei-sem-sen-seo genes, located on the pathogenicity island Type I υSaβ, was detected in 16% of isolates. Interestingly, we observed 6 RAPD genotypes (I to VI) in Staph. aureus isolates, and 2 of these genotypes were strongly associated with the severity of bovine mastitis; there was a close relationship between the RAPD genotypes and SAg genes. Isolates of RAPD type III were more frequently associated with clinical and subclinical mastitis, whereas strains of type VI were mostly related to subclinical mastitis. In addition, SAg genes were related to severity of bovine mastitis. We conclude that an obvious relationship exists among RAPD genotypes, SAg toxin genes, and severity of bovine mastitis.
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Affiliation(s)
- Dong Wang
- Key Laboratory of the Ministry of Education for the Conservation and Utilization of Special Biological Resources of Western China, College of Life Science, Ningxia University, Yinchuan, Ningxia 750021, China
| | - Limei Zhang
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Changfu Yong
- Animal Disease Control and Prevention Center of Shapotou District, Zhongwei, Ningxia 755000, China
| | - Mingliang Shen
- Agriculture and Animal Husbandry Bureau of Shizuishan, Shizuishan, Ningxia 753000, China
| | - Tariq Ali
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Muhammad Shahid
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Kun Han
- Ningxia Center for Disease Control and Prevention, Yinchuan, Ningxia 750004, China
| | - Xuezhang Zhou
- Key Laboratory of the Ministry of Education for the Conservation and Utilization of Special Biological Resources of Western China, College of Life Science, Ningxia University, Yinchuan, Ningxia 750021, China
| | - Bo Han
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
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25
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Spaan AN, van Strijp JAG, Torres VJ. Leukocidins: staphylococcal bi-component pore-forming toxins find their receptors. Nat Rev Microbiol 2017; 15:435-447. [PMID: 28420883 DOI: 10.1038/nrmicro.2017.27] [Citation(s) in RCA: 223] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Staphylococcus aureus is a major bacterial pathogen that causes disease worldwide. The emergence of strains that are resistant to commonly used antibiotics and the failure of vaccine development have resulted in a renewed interest in the pathophysiology of this bacterium. Staphylococcal leukocidins are a family of bi-component pore-forming toxins that are important virulence factors. During the past five years, cellular receptors have been identified for all of the bi-component leukocidins. The identification of the leukocidin receptors explains the cellular tropism and species specificity that is exhibited by these toxins, which has important biological consequences. In this Review, we summarize the recent discoveries that have reignited interest in these toxins and provide an outlook for future research.
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Affiliation(s)
- András N Spaan
- Department of Medical Microbiology, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Jos A G van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, The Netherlands
| | - Victor J Torres
- Department of Microbiology, New York University School of Medicine, 430 East 29th Street, 10016 New York, USA
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26
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Janesch P, Rouha H, Weber S, Malafa S, Gross K, Maierhofer B, Badarau A, Visram ZC, Stulik L, Nagy E. Selective sensitization of human neutrophils to LukGH mediated cytotoxicity by Staphylococcus aureus and IL-8. J Infect 2017; 74:473-483. [PMID: 28237625 DOI: 10.1016/j.jinf.2017.02.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 02/14/2017] [Accepted: 02/17/2017] [Indexed: 01/03/2023]
Abstract
OBJECTIVES Staphylococcus aureus produces up to five bi-component leukocidins - LukSF-PV, gamma-hemolysins AB and CB, LukGH (LukAB) and LukED - to evade innate immunity by lysing phagocytic cells. Species specificity of these leukocidins limits the relevance of animal models, therefore we assessed their individual contribution using human neutrophils. METHODS Human polymorphonuclear leukocytes (PMNs) were activated with stimuli relevant during bacterial infections and sensitivity to recombinant leukocidins was measured in cell-viability assays. Leukocidin receptor expression was quantified by flow cytometry. RESULTS We observed greatly variable sensitivities of different PMN preparations towards LukGH. Activation of PMNs by lipopolysaccharide (LPS) or S. aureus culture supernatant (CS) lacking all leukocidins resulted in higher surface expression of CD11b, the LukGH receptor, and greatly enhanced the sensitivity towards LukGH, eliminating the variability observed with unstimulated cells. In contrast, CS induced a decrease in sensitivity of PMNs to the other four leukocidins and reduced surface staining for their cognate receptors (CXCR1, CXCR2, C5aR, C5L2). Delta-toxin and peptidoglycan mimicked the effect of CS. Moreover, IL-8, an important cytokine in neutrophil activation, also selectively increased LukGH sensitivity. Deletion of lukGH, but not other leukocidin genes, prevented PMN killing upon infection with USA300 CA-MRSA. CONCLUSION Inflammatory signals enhance the susceptibility of human PMNs to lysis by LukGH rendering this toxin dominant among the S. aureus leukocidins in vitro.
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27
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Wang F, Fang RH, Luk BT, Hu CMJ, Thamphiwatana S, Dehaini D, Angsantikul P, Kroll AV, Pang Z, Gao W, Lu W, Zhang L. Nanoparticle-Based Antivirulence Vaccine for the Management of Methicillin-Resistant Staphylococcus aureus Skin Infection. ADVANCED FUNCTIONAL MATERIALS 2016; 26:1628-1635. [PMID: 27325913 PMCID: PMC4912041 DOI: 10.1002/adfm.201505231] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
With the rising threat of antibiotic-resistant bacteria, vaccination is becoming an increasingly important strategy to prevent and manage bacterial infections. Made from deactivated bacterial toxins, toxoid vaccines are widely used in the clinic as they help to combat the virulence mechanisms employed by different pathogens. Herein, the efficacy of a biomimetic nanoparticle-based anti-virulence vaccine is examined in a mouse model of methicillin-resistant Staphylococcus aureus (MRSA) skin infection. Vaccination with nanoparticle-detained staphylococcal α-hemolysin (Hla) effectively triggers the formation of germinal centers and induces high anti-Hla titers. Compared to mice vaccinated with control samples, those vaccinated with the nanoparticle toxoid show superior protective immunity against MRSA skin infection. The vaccination not only inhibits lesion formation at the site of bacterial challenge, but also reduces the invasiveness of MRSA, preventing dissemination into other organs. Overall, this biomimetic nanoparticle-based toxin detainment strategy is a promising method for the design of potent anti-virulence vaccines for managing bacterial infections.
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Affiliation(s)
- Fei Wang
- Department of NanoEngineering and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, U.S.A. Department of Pharmaceutics, School of Pharmacy, Fudan University, and Key Laboratory of Smart Drug Delivery (Fudan University), Ministry of Education, Shanghai 201203, P.R. China
| | - Ronnie H. Fang
- Department of NanoEngineering and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, U.S.A
| | - Brian T. Luk
- Department of NanoEngineering and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, U.S.A
| | - Che-Ming J. Hu
- Department of NanoEngineering and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, U.S.A. Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Soracha Thamphiwatana
- Department of NanoEngineering and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, U.S.A
| | - Diana Dehaini
- Department of NanoEngineering and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, U.S.A
| | - Pavimol Angsantikul
- Department of NanoEngineering and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, U.S.A
| | - Ashley V. Kroll
- Department of NanoEngineering and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, U.S.A
| | - Zhiqing Pang
- Department of NanoEngineering and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, U.S.A. Department of Pharmaceutics, School of Pharmacy, Fudan University, and Key Laboratory of Smart Drug Delivery (Fudan University), Ministry of Education, Shanghai 201203, P.R. China
| | - Weiwei Gao
- Department of NanoEngineering and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, U.S.A
| | - Weiyue Lu
- Department of Pharmaceutics, School of Pharmacy, Fudan University, and Key Laboratory of Smart Drug Delivery (Fudan University), Ministry of Education, Shanghai 201203, P.R. China
| | - Liangfang Zhang
- Department of NanoEngineering and Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, U.S.A
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28
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Reyes-Robles T, Lubkin A, Alonzo F, Lacy DB, Torres VJ. Exploiting dominant-negative toxins to combat Staphylococcus aureus pathogenesis. EMBO Rep 2016; 17:428-40. [PMID: 26882549 DOI: 10.15252/embr.201540994] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 01/05/2016] [Indexed: 12/12/2022] Open
Abstract
Staphylococcus aureus (S. aureus) is a human pathogen that relies on the subversion of host phagocytes to support its pathogenic lifestyle. S. aureus strains can produce up to five beta-barrel, bi-component, pore-forming leukocidins that target and kill host phagocytes. Thus, preventing immune cell killing by these toxins is likely to boost host immunity. Here, we describe the identification of glycine-rich motifs within the membrane-penetrating stem domains of the leukocidin subunits that are critical for killing primary human neutrophils. Remarkably, leukocidins lacking these glycine-rich motifs exhibit dominant-negative inhibitory effects toward their wild-type toxin counterparts as well as other leukocidins. Biochemical and cellular assays revealed that these dominant-negative toxins work by forming mixed complexes that are impaired in pore formation. The dominant-negative leukocidins inhibited S. aureus cytotoxicity toward primary human neutrophils, protected mice from lethal challenge by wild-type leukocidin, and reduced bacterial burden in a murine model of bloodstream infection. Thus, we describe the first example of staphylococcal bi-component dominant-negative toxins and their potential as novel therapeutics to combat S. aureus infection.
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Affiliation(s)
- Tamara Reyes-Robles
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Ashira Lubkin
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Francis Alonzo
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - D Borden Lacy
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Victor J Torres
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
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29
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Abstract
Staphylococcus aureus is a leading pathogen in surgical site, intensive care unit, and skin infections, as well as healthcare-associated pneumonias. These infections are associated with an enormous burden of morbidity, mortality, and increase of hospital length of stay and patient cost. S. aureus is impressively fast in acquiring antibiotic resistance, and multidrug-resistant strains are a serious threat to human health. Due to resistance or insufficient effectiveness, antibiotics and bundle measures leave a tremendous unmet medical need worldwide. There are no licensed vaccines on the market despite the significant efforts done by public and private initiatives. Indeed, vaccines tested in clinical trials in the last two decades have failed to show efficacy. However, they targeted single antigens and contained no adjuvants and efficacy trials were performed in severely ill subjects. Herein, we provide a comprehensive evaluation of potential target populations for efficacy trials taking into account key factors such as population size, incidence of S. aureus infection, disease outcome, primary endpoints, as well as practical advantages and disadvantages. We describe the whole-blood assay as a potential surrogate of protection, and we show the link between phase III clinical trial data of failed vaccines with their preclinical observations. Finally, we give our perspective on how new vaccine formulations and clinical development approaches may lead to successful S. aureus vaccines.
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30
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Petinaki E, Spiliopoulou I. Methicillin-resistant Staphylococcus aureus colonization and infection risks from companion animals: current perspectives. VETERINARY MEDICINE-RESEARCH AND REPORTS 2015; 6:373-382. [PMID: 30101122 PMCID: PMC6067666 DOI: 10.2147/vmrr.s91313] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) remains one of the most virulent human pathogens and has also recently been recognized as such in the veterinary settings. Companion animals, including dogs, cats, horses, small exotic animals, wildlife animals, and livestock, may constitute a reservoir for MRSA transmission to humans and vice versa. The evolution, emergence, and risk factors for MRSA transmission among colonized or infected animals are reviewed in the present paper, and infection control practices are discussed.
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Affiliation(s)
- Efthimia Petinaki
- Department of Microbiology, School of Medicine, University of Thessalia, Larissa
| | - Iris Spiliopoulou
- Department of Microbiology, School of Medicine, University of Patras, Patras, Greece,
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31
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Rouha H, Badarau A, Visram ZC, Battles MB, Prinz B, Magyarics Z, Nagy G, Mirkina I, Stulik L, Zerbs M, Jägerhofer M, Maierhofer B, Teubenbacher A, Dolezilkova I, Gross K, Banerjee S, Zauner G, Malafa S, Zmajkovic J, Maier S, Mabry R, Krauland E, Wittrup KD, Gerngross TU, Nagy E. Five birds, one stone: neutralization of α-hemolysin and 4 bi-component leukocidins of Staphylococcus aureus with a single human monoclonal antibody. MAbs 2015; 7:243-54. [PMID: 25523282 PMCID: PMC5045134 DOI: 10.4161/19420862.2014.985132] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Staphylococcus aureus is a major human pathogen associated with high mortality. The emergence of antibiotic resistance and the inability of antibiotics to counteract bacterial cytotoxins involved in the pathogenesis of S. aureus call for novel therapeutic approaches, such as passive immunization with monoclonal antibodies (mAbs). The complexity of staphylococcal pathogenesis and past failures with single mAb products represent considerable barriers for antibody-based therapeutics. Over the past few years, efforts have focused on neutralizing α-hemolysin. Recent findings suggest that the concerted actions of several cytotoxins, including the bi-component leukocidins play important roles in staphylococcal pathogenesis. Therefore, we aimed to isolate mAbs that bind to multiple cytolysins by employing high diversity human IgG1 libraries presented on the surface of yeast cells. Here we describe cross-reactive antibodies with picomolar affinity for α-hemolysin and 4 different bi-component leukocidins that share only ∼26% overall amino acid sequence identity. The molecular basis of cross-reactivity is the recognition of a conformational epitope shared by α-hemolysin and F-components of gamma-hemolysin (HlgAB and HlgCB), LukED and LukSF (Panton-Valentine Leukocidin). The amino acids predicted to form the epitope are conserved and known to be important for cytotoxic activity. We found that a single cross-reactive antibody prevented lysis of human phagocytes, epithelial and red blood cells induced by α-hemolysin and leukocidins in vitro, and therefore had superior effectiveness compared to α-hemolysin specific antibodies to protect from the combined cytolytic effect of secreted S. aureus toxins. Such mAb afforded high levels of protection in murine models of pneumonia and sepsis.
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Key Words
- BLI, biolayer interferometry
- EC50, effective concentration
- Hla, α-hemolysin
- HlgAB and HlgCB, gamma-hemolysins
- IC50, inhibitory concentration
- LukED, leukocidin ED
- LukSF, leukocidin SF
- PMN, polymorphonuclear cells
- RBC, red blood cell
- Staphylococcus aureus
- engineered cross-reactivity
- exotoxins
- in vitro potency
- in vivo efficacy
- mAb, monoclonal antibody
- monoclonal antibody
- toxin neutralization
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32
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Adhikari RP, Kort T, Shulenin S, Kanipakala T, Ganjbaksh N, Roghmann MC, Holtsberg FW, Aman MJ. Antibodies to S. aureus LukS-PV Attenuated Subunit Vaccine Neutralize a Broad Spectrum of Canonical and Non-Canonical Bicomponent Leukotoxin Pairs. PLoS One 2015; 10:e0137874. [PMID: 26367030 PMCID: PMC4569305 DOI: 10.1371/journal.pone.0137874] [Citation(s) in RCA: 24] [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: 05/21/2015] [Accepted: 08/22/2015] [Indexed: 11/18/2022] Open
Abstract
S. aureus vaccine development has proven particularly difficult. The conventional approach to achieve sterile immunity through opsonophagocytic killing has been largely unsuccessful. S. aureus is highly toxigenic and a great body of evidence suggests that a successful future vaccine for this organism should target extracellular toxins which are responsible for host tissue destruction and immunosuppression. Major staphylococcal toxins are alpha toxin (a single subunit hemolysin) along with a group of bicomponent pore-forming toxins (BCPFT), namely Panton-Valentine leukocidin (PVL), gamma hemolysins (HlgCB and AB), LukAB and LukED. In our previous report, an attenuated mutant of LukS-PV (PVL- S subunit) named as “LukS-mut9” elicited high immunogenic response as well as provided a significant protection in a mouse sepsis model. Recent discovery of PVL receptors shows that mice lack receptors for this toxin, thus the reported protection of mice with the PVL vaccine may relate to cross protective responses against other homologous toxins. This manuscript addresses this issue by demonstrating that polyclonal antibody generated by LukS-mut9 can neutralize other canonical and non-canonical leukotoxin pairs. In this report, we also demonstrated that several potent toxins can be created by non-canonical pairing of subunits. Out of 5 pairs of canonical and 8 pairs of non-canonical toxins tested, anti-LukS-mut9 polyclonal antibodies neutralized all except for LukAB. We also studied the potential hemolytic activities of canonical and noncanonical pairs among biocomponent toxins and discovered that a novel non-canonical pair consisting of HlgA and LukD is a highly toxic combination. This pair can lyse RBC from different species including human blood far better than alpha hemolysin. Moreover, to follow-up our last report, we explored the correlation between the levels of pre-existing antibodies to new sets of leukotoxins subunits and clinical outcomes in adult patients with S. aureus bacteremia. We found that there is an inversed correlation between the antibody titer to sepsis for leukotoxins LukS-mut9, LukF-PV, HlgC, LukE and LukAB, suggesting the risk of sepsis was significantly lower in the patients with higher antibody titer against those toxins.
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Affiliation(s)
- Rajan P. Adhikari
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
- * E-mail:
| | - Thomas Kort
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | - Sergey Shulenin
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | | | - Nader Ganjbaksh
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
| | - Mary-Claire Roghmann
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- VA Maryland Health Care System, Baltimore, Maryland, United States of America
| | | | - M. Javad Aman
- Integrated Biotherapeutics Inc., Gaithersburg, Maryland, United States of America
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33
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Badarau A, Rouha H, Malafa S, Logan DT, Håkansson M, Stulik L, Dolezilkova I, Teubenbacher A, Gross K, Maierhofer B, Weber S, Jägerhofer M, Hoffman D, Nagy E. Structure-function analysis of heterodimer formation, oligomerization, and receptor binding of the Staphylococcus aureus bi-component toxin LukGH. J Biol Chem 2014; 290:142-56. [PMID: 25371205 DOI: 10.1074/jbc.m114.598110] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The bi-component leukocidins of Staphylococcus aureus are important virulence factors that lyse human phagocytic cells and contribute to immune evasion. The γ-hemolysins (HlgAB and HlgCB) and Panton-Valentine leukocidin (PVL or LukSF) were shown to assemble from soluble subunits into membrane-bound oligomers on the surface of target cells, creating barrel-like pore structures that lead to cell lysis. LukGH is the most distantly related member of this toxin family, sharing only 30-40% amino acid sequence identity with the others. We observed that, unlike other leukocidin subunits, recombinant LukH and LukG had low solubility and were unable to bind to target cells, unless both components were present. Using biolayer interferometry and intrinsic tryptophan fluorescence we detected binding of LukH to LukG in solution with an affinity in the low nanomolar range and dynamic light scattering measurements confirmed formation of a heterodimer. We elucidated the structure of LukGH by x-ray crystallography at 2.8-Å resolution. This revealed an octameric structure that strongly resembles that reported for HlgAB, but with important structural differences. Structure guided mutagenesis studies demonstrated that three salt bridges, not found in other bi-component leukocidins, are essential for dimer formation in solution and receptor binding. We detected weak binding of LukH, but not LukG, to the cellular receptor CD11b by biolayer interferometry, suggesting that in common with other members of this toxin family, the S-component has the primary contact role with the receptor. These new insights provide the basis for novel strategies to counteract this powerful toxin and Staphylococcus aureus pathogenesis.
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Affiliation(s)
- Adriana Badarau
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Harald Rouha
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Stefan Malafa
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Derek T Logan
- SARomics Biostructures AB, Medicon Village, S-223 81 Lund, Sweden
| | - Maria Håkansson
- SARomics Biostructures AB, Medicon Village, S-223 81 Lund, Sweden
| | - Lukas Stulik
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Ivana Dolezilkova
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Astrid Teubenbacher
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Karin Gross
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Barbara Maierhofer
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Susanne Weber
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Michaela Jägerhofer
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - David Hoffman
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
| | - Eszter Nagy
- From Arsanis Biosciences, Vienna Biocenter Campus, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria and
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