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Savin A, Anderson EE, Dyzenhaus S, Podkowik M, Shopsin B, Pironti A, Torres VJ. Staphylococcus aureus senses human neutrophils via PerR to coordinate the expression of the toxin LukAB. Infect Immun 2024; 92:e0052623. [PMID: 38235972 PMCID: PMC10863418 DOI: 10.1128/iai.00526-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 12/20/2023] [Indexed: 01/19/2024] Open
Abstract
Staphylococcus aureus is a gram-positive pathogen that poses a major health concern, in part due to its large array of virulence factors that allow infection and evasion of the immune system. One of these virulence factors is the bicomponent pore-forming leukocidin LukAB. The regulation of lukAB expression is not completely understood, especially in the presence of immune cells such as human polymorphonuclear neutrophils (hPMNs). Here, we screened for transcriptional regulators of lukAB during the infection of primary hPMNs. We uncovered that PerR, a peroxide sensor, is vital for hPMN-mediated induction of lukAB and that PerR upregulates cytotoxicity during the infection of hPMNs. Exposure of S. aureus to hydrogen peroxide (H2O2) alone also results in increased lukAB promoter activity, a phenotype dependent on PerR. Collectively, our data suggest that S. aureus uses PerR to sense the H2O2 produced by hPMNs to stimulate the expression of lukAB, allowing the bacteria to withstand these critical innate immune cells.IMPORTANCEStaphylococcus aureus utilizes a diverse set of virulence factors, such as leukocidins, to subvert human neutrophils, but how these toxins are regulated is incompletely defined. Here, we identified the peroxide-sensitive repressor, PerR, as a required protein involved in the induction of lukAB in the presence of primary human neutrophils, a phenotype directly linked to the ability of PerR to sense H2O2. Thus, we show that S. aureus coordinates sensing and resistance to oxidative stress with toxin production to promote pathogen survival.
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Affiliation(s)
- Avital Savin
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
- Department of Biology, New York University, New York, New York, USA
| | - Exene E. Anderson
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Sophie Dyzenhaus
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Magdalena Podkowik
- Antimicrobial-Resistant Pathogens Program, New York University Grossman School of Medicine, New York, New York, USA
- Division of Infectious Diseases, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
| | - Bo Shopsin
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
- Antimicrobial-Resistant Pathogens Program, New York University Grossman School of Medicine, New York, New York, USA
- Division of Infectious Diseases, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
| | - Alejandro Pironti
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
- Antimicrobial-Resistant Pathogens Program, New York University Grossman School of Medicine, New York, New York, USA
| | - Victor J. Torres
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
- Department of Host-Microbe Interactions, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
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Langouët-Astrié C, Oshima K, McMurtry SA, Yang Y, Kwiecinski JM, LaRivière WB, Kavanaugh JS, Zakharevich I, Hansen KC, Shi D, Zhang F, Boguslawski KM, Perelman SS, Su G, Torres VJ, Liu J, Horswill AR, Schmidt EP. The influenza-injured lung microenvironment promotes MRSA virulence, contributing to severe secondary bacterial pneumonia. Cell Rep 2022; 41:111721. [PMID: 36450248 PMCID: PMC10082619 DOI: 10.1016/j.celrep.2022.111721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 10/12/2022] [Accepted: 11/03/2022] [Indexed: 12/03/2022] Open
Abstract
Influenza infection is substantially worsened by the onset of secondary pneumonia caused by bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA). The bidirectional interaction between the influenza-injured lung microenvironment and MRSA is poorly understood. By conditioning MRSA ex vivo in bronchoalveolar lavage fluid collected from mice at various time points of influenza infection, we found that the influenza-injured lung microenvironment dynamically induces MRSA to increase cytotoxin expression while decreasing metabolic pathways. LukAB, a SaeRS two-component system-dependent cytotoxin, is particularly important to the severity of post-influenza MRSA pneumonia. LukAB's activity is likely shaped by the post-influenza lung microenvironment, as LukAB binds to (and is activated by) heparan sulfate (HS) oligosaccharide sequences shed from the epithelial glycocalyx after influenza. Our findings indicate that post-influenza MRSA pneumonia is shaped by bidirectional host-pathogen interactions: host injury triggers changes in bacterial expression of toxins, the activity of which may be shaped by host-derived HS fragments.
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Affiliation(s)
| | - Kaori Oshima
- Division of Pulmonary Sciences and Critical Care, University of Colorado Denver, Aurora, CO 80045, USA
| | - Sarah A McMurtry
- Division of Pulmonary Sciences and Critical Care, University of Colorado Denver, Aurora, CO 80045, USA
| | - Yimu Yang
- Division of Pulmonary Sciences and Critical Care, University of Colorado Denver, Aurora, CO 80045, USA
| | - Jakub M Kwiecinski
- Department of Immunology & Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA; Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow 30387, Poland
| | - Wells B LaRivière
- Division of Pulmonary Sciences and Critical Care, University of Colorado Denver, Aurora, CO 80045, USA; Medical Scientist Training Program, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Jeffrey S Kavanaugh
- Department of Immunology & Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Igor Zakharevich
- Department of Biochemistry and Molecular Genetics, University of Colorado, Aurora, CO 80045, USA
| | - Kirk C Hansen
- Department of Biochemistry and Molecular Genetics, University of Colorado, Aurora, CO 80045, USA
| | - Deling Shi
- Department of Chemistry, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Fuming Zhang
- Department of Chemistry, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Kristina M Boguslawski
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - Sofya S Perelman
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - Gouwei Su
- University of North Carolina Eshelman School of Pharmacy, Chapel Hill, NC 27599, USA
| | - Victor J Torres
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - Jian Liu
- University of North Carolina Eshelman School of Pharmacy, Chapel Hill, NC 27599, USA
| | - Alexander R Horswill
- Department of Immunology & Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Eric P Schmidt
- Division of Pulmonary Sciences and Critical Care, University of Colorado Denver, Aurora, CO 80045, USA; Department of Medicine, Massachusetts General Hospital, Boston, MA 02115, USA
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Zheng X, Ma SX, St John A, Torres VJ. The Major Autolysin Atl Regulates the Virulence of Staphylococcus aureus by Controlling the Sorting of LukAB. Infect Immun 2022;:e0005622. [PMID: 35258336 DOI: 10.1128/iai.00056-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Infections caused by the Gram-positive bacterium Staphylococcus aureus remain a significant health threat globally. The production of bicomponent pore-forming leukocidins plays an important role in S. aureus pathogenesis. Transcriptionally, these toxins are primarily regulated by the Sae and Agr regulatory systems. However, the posttranslational regulation of these toxins is largely unexplored. In particular, one of the leukocidins, LukAB, has been shown to be both secreted into the extracellular milieu and associated with the bacterial cell envelope. Here, we report that a major cell wall hydrolase, autolysin (Atl), controls the sorting of LukAB from the cell envelope to the extracellular milieu, an effect independent of transcriptional regulation. By influencing the sorting of LukAB, Atl modulates S. aureus cytotoxicity toward primary human neutrophils. Mechanistically, we found that the reduction in peptidoglycan cleavage and increased LukAB secretion in the atl mutant can be reversed through the supplementation of exogenous mutanolysin. Altogether, our study revealed that the cell wall hydrolase activity of Atl and the cleavage of peptidoglycan play an important role in controlling the sorting of S. aureus toxins during secretion.
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Kailasan S, Kort T, Mukherjee I, Liao GC, Kanipakala T, Williston N, Ganjbaksh N, Venkatasubramaniam A, Holtsberg FW, Karauzum H, Adhikari RP, Aman MJ. Rational Design of Toxoid Vaccine Candidates for Staphylococcus aureus Leukocidin AB ( LukAB). Toxins (Basel) 2019; 11:E339. [PMID: 31207937 DOI: 10.3390/toxins11060339] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Wood JB, Jones LS, Soper NR, Xu M, Torres VJ, Buddy Creech C, Thomsen IP. Serologic Detection of Antibodies Targeting the Leukocidin LukAB Strongly Predicts Staphylococcus aureus in Children With Invasive Infection. J Pediatric Infect Dis Soc 2018. [PMID: 29538707 PMCID: PMC6510946 DOI: 10.1093/jpids/piy017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Staphylococcus aureus is among the most commonly identified causes of invasive bacterial infection in children; however, reliable results from cultures of sterile-site samples often cannot be obtained, which necessitates prescription of a broad empiric antimicrobial agent(s). Children with invasive S aureus infection rapidly generate high antibody titers to the cytotoxin LukAB; therefore, the aim of this study was to assess the diagnostic utility of an anti-LukAB antibody assay for children with musculoskeletal infection (MSKI). METHODS We conducted a 2-year prospective study of all eligible children admitted to Vanderbilt Children's Hospital with an MSKI. Acute and convalescent sera were obtained, and antibodies that target LukAB were measured by an enzyme-linked immunosorbent assay. RESULTS Forty-two children were enrolled. The median concentrations of LukAB antibodies for children with S aureus infection were 130.3 U/mL in the acute phase and 455 U/mL in the convalescent phase (P < .001). The median concentrations of LukAB antibodies in children with a non-S aureus MSKI were 8.6 U/mL in the acute phase and 9.7 U/mL in the convalescent phase. The assay discriminated between S aureus and non-S aureus infection with areas under the receiver operating characteristic curve of 0.81 (95% confidence interval, 0.67-0.95; P < .001) and 0.95 (95% confidence interval, 0.86-1; P < .001) for samples tested in the acute and follow-up periods, respectively. With no false-negative results, the assay accurately ruled out S aureus in samples obtained during the convalescent phase. CONCLUSION Culture-independent diagnostics have the potential to improve care by narrowing antimicrobial therapy on the basis of the likelihood of S aureus infection. The results of this proof-of-concept study suggest that a LukAB serologic assay might be useful in the diagnosis of invasive bacterial infections, and larger-scale validation studies are warranted.
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Affiliation(s)
- James B Wood
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Nashville, Tennessee,Correspondence: J. B. Wood, Vanderbilt University Medical Center, Division of Pediatric Infectious Diseases, 1161 21st Ave South, D-7235 MCN, Nashville, TN 37232 ()
| | - Lauren S Jones
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Nashville, Tennessee
| | - Nicole R Soper
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Nashville, Tennessee
| | - Meng Xu
- Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Victor J Torres
- Department of Microbiology, New York University School of Medicine, New York
| | - C Buddy Creech
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Nashville, Tennessee
| | - Isaac P Thomsen
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Nashville, Tennessee
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Wood JB, Jones LS, Soper NR, Nagarsheth M, Creech CB, Thomsen IP. Commercial Intravenous Immunoglobulin Preparations Contain Functional Neutralizing Antibodies against the Staphylococcus aureus Leukocidin LukAB (LukGH). Antimicrob Agents Chemother 2017; 61:e00968-17. [PMID: 28874371 DOI: 10.1128/AAC.00968-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 08/26/2017] [Indexed: 11/20/2022] Open
Abstract
The pathogenesis of Staphylococcus aureus is mediated by an array of important virulence factors, including the two-component leukocidin family of toxins. LukAB (also known as LukGH), the most recently discovered leukocidin, is potently lethal to phagocytes, produced during invasive human disease, and present in all known clinical isolates of S. aureus Intravenous immunoglobulin (IVIg) is often used clinically in severe S. aureus infections. The primary aim of this study was to assess the binding and neutralization potential of IVIg against LukAB. A secondary aim was to examine the lot-to-lot variability of IVIg in the binding and neutralization of LukAB. We studied 24 distinct lots of IVIg and compared them to serum from children with invasive S. aureus infection (in the acute and convalescent phases) and from healthy, uninfected controls. We found that all lots of IVIg contained functional antibodies targeting LukAB. After adjusting for total antibody content per sample, we found that the amount of anti-LukAB antibody in IVIg was similar to that seen with healthy controls and less than that seen with patients with invasive S. aureus infection. IVIg samples had lower neutralization capacity than samples from healthy controls and children with invasive infection. IVIg had remarkably little lot-to-lot variation in LukAB binding but had significantly more variation in toxin neutralization. These results represent the first report of functional antibodies against the important S. aureus leukocidin LukAB in IVIg. Given the frequent clinical use of IVIg for severe S. aureus infections, improving our understanding of functional antibody properties exhibited by this therapeutic is essential.
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Thomsen IP, Sapparapu G, James DBA, Cassat JE, Nagarsheth M, Kose N, Putnam N, Boguslawski KM, Jones LS, Wood JB, Creech CB, Torres VJ, Crowe JE. Monoclonal Antibodies Against the Staphylococcus aureus Bicomponent Leukotoxin AB Isolated Following Invasive Human Infection Reveal Diverse Binding and Modes of Action. J Infect Dis 2017; 215:1124-1131. [PMID: 28186295 PMCID: PMC5426380 DOI: 10.1093/infdis/jix071] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Accepted: 01/30/2017] [Indexed: 12/15/2022] Open
Abstract
The 2-component leukotoxin LukAB is critical for Staphylococcus aureus targeting and killing of human neutrophils ex vivo and is produced in the setting of human infection. We report 3 LukAB-specific human monoclonal antibodies (mAbs) with distinct mechanisms of toxin neutralization and in vivo efficacy. Three hybridomas secreting mAbs with anti-LukAB activity (designated SA-13, -15, and -17) were generated from B cells obtained from a 12-year-old boy with S. aureus osteomyelitis. Each of the 3 mAbs neutralized LukAB-mediated neutrophil toxicity, exhibited differing levels of potency, recognized different antigenic sites on the toxin, and displayed at least 2 distinct mechanisms for cytotoxic inhibition. SA-15 bound exclusively to the dimeric form of the toxin, suggesting that human B cells recognize epitopes on the dimerized form of LukAB during natural infection. Both SA-13 and SA-17 bound the LukA monomer and the LukAB dimer. Although all 3 mAbs potently neutralized cytotoxicity, only SA-15 and SA-17 significantly inhibited toxin association with the cell surface. Treatment with a 1:1 mixture of mAbs SA-15 and SA-17 resulted in significantly lower bacterial colony counts in heart, liver, and kidneys in a murine model of S. aureus sepsis. These data describe the isolation of diverse and efficacious antitoxin mAbs.
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Affiliation(s)
| | | | - David B A James
- Department of Microbiology, New York University School of Medicine, New York, New York
| | - James E Cassat
- Department of Pediatrics
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee ; and
| | | | | | - Nicole Putnam
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee; and
| | | | | | | | | | - Victor J Torres
- Department of Microbiology, New York University School of Medicine, New York, New York
| | - James E Crowe
- Department of Pediatrics
- Vanderbilt Vaccine Center, and
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee ; and
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Münzenmayer L, Geiger T, Daiber E, Schulte B, Autenrieth SE, Fraunholz M, Wolz C. Influence of Sae-regulated and Agr-regulated factors on the escape of Staphylococcus aureus from human macrophages. Cell Microbiol 2016; 18:1172-83. [PMID: 26895738 DOI: 10.1111/cmi.12577] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 01/12/2016] [Accepted: 01/26/2016] [Indexed: 02/03/2023]
Abstract
Although Staphylococcus aureus is not a classical intracellular pathogen, it can survive within phagocytes and many other cell types. However, the pathogen is also able to escape from cells by mechanisms that are only partially understood. We analysed a series of isogenic S. aureus mutants of the USA300 derivative JE2 for their capacity to destroy human macrophages from within. Intracellular S. aureus JE2 caused severe cell damage in human macrophages and could efficiently escape from within the cells. To obtain this full escape phenotype including an intermittent residency in the cytoplasm, the combined action of the regulatory systems Sae and Agr is required. Mutants in Sae or mutants deficient in the Sae target genes lukAB and pvl remained in high numbers within the macrophages causing reduced cell damage. Mutants in the regulatory system Agr or in the Agr target gene psmα were largely similar to wild-type bacteria concerning cell damage and escape efficiency. However, these strains were rarely detectable in the cytoplasm, emphasizing the role of phenol-soluble modulins (PSMs) for phagosomal escape. Thus, Sae-regulated toxins largely determine damage and escape from within macrophages, whereas PSMs are mainly responsible for the escape from the phagosome into the cytoplasm. Damage of macrophages induced by intracellular bacteria was linked neither to activation of apoptosis-related caspase 3, 7 or 8 nor to NLRP3-dependent inflammasome activation.
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Affiliation(s)
- Lisa Münzenmayer
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Tobias Geiger
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany.,School of Medicine, Section of Microbial Pathogenesis Boyer Center for Molecular Medicine Yale University, New Haven, CT, 06536, USA
| | - Ellen Daiber
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Berit Schulte
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Stella E Autenrieth
- Department of Internal Medicine II, University of Tübingen, Tübingen, Germany
| | - Martin Fraunholz
- Department of Microbiology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Christiane Wolz
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
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Chadha AD, Thomsen IP, Jimenez-Truque N, Soper NR, Jones LS, Sokolow AG, Torres VJ, Creech CB. Host response to Staphylococcus aureus cytotoxins in children with cystic fibrosis. J Cyst Fibros 2016; 15:597-604. [PMID: 26821814 DOI: 10.1016/j.jcf.2015.12.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 12/22/2015] [Accepted: 12/23/2015] [Indexed: 12/14/2022]
Abstract
BACKGROUND Staphylococcus aureus is one of the earliest bacterial pathogens to colonize the lungs of children with cystic fibrosis and is an important contributor to pulmonary exacerbations. The adaptive host response to S. aureus in cystic fibrosis remains inadequately defined and has important implications for pathogenesis and potential interventions. The objectives of this study were to determine the functional antibody response to select staphylococcal exotoxins (LukAB, alpha-hemolysin, and PVL) in children with cystic fibrosis and to evaluate the relationship of this response with pulmonary exacerbations. METHODS Fifty children with cystic fibrosis were enrolled and followed prospectively for 12months. Clinical characteristics and serologic profiles were assessed at routine visits and during pulmonary exacerbations, and functional antibody assessments were performed to measure neutralization of LukAB-mediated cytotoxicity. RESULTS For each antigen, geometric mean titers were significantly higher if S. aureus was detected at the time of exacerbation. For LukAB, geometric mean titers were significantly higher at exacerbation follow-up compared to titers during the exacerbation, consistent with expression during human disease, and the humoral response capably neutralized LukAB-mediated cytotoxicity. Moreover, the presence of a positive S. aureus culture during a pulmonary exacerbation was associated with 31-fold higher odds of having a LukA titer ≥1:160, suggesting potential diagnostic capability of this assay. CONCLUSIONS The leukotoxin LukAB is expressed by S. aureus and recognized by the human adaptive immune response in the setting of pulmonary infection in cystic fibrosis. Anti-LukAB antibodies were not only predictive of positive staphylococcal culture during exacerbation, but also functional in the neutralization of this toxin.
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Affiliation(s)
- Ashley D Chadha
- Department of Pediatrics, Division of Allergy, Immunology, and Pulmonary Medicine, The Monroe Carell, Jr. Children's Hospital at Vanderbilt and the Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Isaac P Thomsen
- Department of Pediatrics, Division of Infectious Diseases, The Monroe Carell, Jr. Children's Hospital at Vanderbilt and the Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Natalia Jimenez-Truque
- Department of Pediatrics, Division of Infectious Diseases, The Monroe Carell, Jr. Children's Hospital at Vanderbilt and the Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Nicole R Soper
- Department of Pediatrics, Division of Infectious Diseases, The Monroe Carell, Jr. Children's Hospital at Vanderbilt and the Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Lauren S Jones
- Department of Pediatrics, Division of Infectious Diseases, The Monroe Carell, Jr. Children's Hospital at Vanderbilt and the Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Andrew G Sokolow
- Department of Pediatrics, Division of Allergy, Immunology, and Pulmonary Medicine, The Monroe Carell, Jr. Children's Hospital at Vanderbilt and the Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Victor J Torres
- Department of Microbiology, New York University School of Medicine, New York, NY
| | - C Buddy Creech
- Department of Pediatrics, Division of Infectious Diseases, The Monroe Carell, Jr. Children's Hospital at Vanderbilt and the Vanderbilt University School of Medicine, Nashville, Tennessee
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