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Paul S, Todd OA, Eichelberger KR, Tkaczyk C, Sellman BR, Noverr MC, Cassat JE, Fidel PL, Peters BM. A fungal metabolic regulator underlies infectious synergism during Candida albicans - Staphylococcus aureus intra-abdominal co-infection. bioRxiv 2024:2024.02.15.580531. [PMID: 38405692 PMCID: PMC10888754 DOI: 10.1101/2024.02.15.580531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Candida albicans and Staphylococcus aureus are two commonly associated pathogens that cause nosocomial infections with high morbidity and mortality. Our prior and current work using a murine model of polymicrobial intra-abdominal infection (IAI) uncovered synergistic lethality that was driven by Candida -induced upregulation of functional S. aureus ⍺-toxin leading to polymicrobial sepsis and organ damage. In order to determine the candidal effector(s) mediating enhanced virulence, an unbiased screen of C. albicans transcription factor mutants was undertaken and revealed that zcf13 Δ/Δ failed to drive augmented ⍺-toxin or lethal synergism during co-infection. Using a combination of transcriptional and phenotypic profiling approaches, ZCF13 was shown to regulate genes involved in pentose metabolism, including RBK1 and HGT7 that contribute to fungal ribose catabolism and uptake, respectively. Subsequent experiments revealed that ribose inhibited the staphylococcal agr quorum sensing system and concomitantly repressed toxicity. Unlike wild-type C. albicans , zcf13 Δ/Δ was unable to effectively utilize ribose during co-culture or co-infection leading to exogenous ribose accumulation and agr repression. Forced expression of RBK1 and HGT7 in the zcf13 Δ/Δ mutant fully restored pathogenicity during co-infection. Collectively, our results detail the interwoven complexities of cross-kingdom interactions and highlight how intermicrobial metabolism impacts polymicrobial disease pathogenesis with devastating consequences for the host.
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Nguyen NTQ, Doan TNM, Sato K, Tkaczyk C, Sellman BR, Diep BA. Monoclonal antibodies neutralizing alpha-hemolysin, bicomponent leukocidins, and clumping factor A protected against Staphylococcus aureus-induced acute circulatory failure in a mechanically ventilated rabbit model of hyperdynamic septic shock. Front Immunol 2023; 14:1260627. [PMID: 37781371 PMCID: PMC10541218 DOI: 10.3389/fimmu.2023.1260627] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 08/22/2023] [Indexed: 10/03/2023] Open
Abstract
Background Patients with septic shock caused by Staphylococcus aureus have mortality rates exceeding 50%, despite appropriate antibiotic therapy. Our objectives were to establish a rabbit model of S. aureus septic shock and to determine whether a novel immunotherapy can prevent or halt its natural disease progression. Methods Anesthetized rabbits were ventilated with lung-protective low-tidal volume, instrumented for advanced hemodynamic monitoring, and characterized for longitudinal changes in acute myocardial dysfunction by echocardiography and sepsis-associated biomarkers after S. aureus intravenous challenge. To demonstrate the potential utility of this hyperdynamic septic shock model for preclinical drug development, rabbits were randomized for prophylaxis with anti-Hla/Luk/ClfA monoclonal antibody combination that neutralizes alpha-hemolysin (Hla), the bicomponent pore-forming leukocidins (Luk) including Panton-Valentine leukocidin, leukocidin ED, and gamma-hemolysin, and clumping factor A (ClfA), or an irrelevant isotype-matched control IgG (c-IgG), and then challenged with S. aureus. Results Rabbits challenged with S. aureus, but not those with saline, developed a hyperdynamic state of septic shock characterized by elevated cardiac output (CO), increased stroke volume (SV) and reduced systemic vascular resistance (SVR), which was followed by a lethal hypodynamic state characterized by rapid decline in mean arterial pressure (MAP), increased central venous pressure, reduced CO, reduced SV, elevated SVR, and reduced left-ventricular ejection fraction, thereby reproducing the hallmark clinical features of human staphylococcal septic shock. In this model, rabbits pretreated with anti-Hla/Luk/ClfA mAb combination had 69% reduction in mortality when compared to those pretreated with c-IgG (P<0.001). USA300-induced acute circulatory failure-defined as >70% decreased in MAP from pre-infection baseline-occurred in only 20% (2/10) of rabbits pretreated with anti-Hla/Luk/ClfA mAb combination compared to 100% (9/9) of those pretreated with c-IgG. Prophylaxis with anti-Hla/Luk/ClfA mAb combination halted progression to lethal hypodynamic shock, as evidenced by significant protection against the development of hyperlactatemia, hypocapnia, hyperkalemia, leukopenia, neutropenia, monocytopenia, lymphopenia, as well as biomarkers associated with acute myocardial injury. Conclusion These results demonstrate the potential utility of a mechanically ventilated rabbit model that reproduced hallmark clinical features of hyperdynamic septic shock and the translational potential of immunotherapy targeting S. aureus virulence factors for the prevention of staphylococcal septic shock.
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Affiliation(s)
- 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 N. M. Doan
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Kei Sato
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Christine Tkaczyk
- Early Vaccines and Immune Therapies, AstraZeneca, Gaithersburg, MD, United States
| | - Bret R. Sellman
- Early Vaccines and Immune Therapies, AstraZeneca, Gaithersburg, MD, 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
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3
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Boyd J, Fuentes N, Tkaczyk C. Developing an Image Based Deep Learning Approach to Immune Cell Quantification in a Mouse Asthma Model. Microsc Microanal 2023; 29:1071-1072. [PMID: 37613378 DOI: 10.1093/micmic/ozad067.550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Jonathan Boyd
- Dynamic Omics, Centre of Genomics Research, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, Maryland, United States
| | - Nathalie Fuentes
- Late-Stage Formulation Sciences, Dosage Form Design and Development, Biopharmaceutical, AstraZeneca, Development, Gaithersburg, Maryland, United States
| | - Christine Tkaczyk
- Bacteriology, Early Vaccines & Immune Therapies, AstraZeneca, Gaithersburg, Maryland, United States
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4
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Tabor DE, Tkaczyk C, Tovchigrechko A, Sellman BR, McCarthy M, Ren P, Shoemaker K, Jafri HS, François B, Esser MT, Coppens J, Timbermont L, Xavier B, Lammens C, Goossens H, Malhotra-Kumar S, Ruzin A. 1486. Phylogenetic and alpha toxin variant analyses of Staphylococcus aureus strains isolated from patients during the SAATELLITE study. Open Forum Infect Dis 2020. [PMCID: PMC7777803 DOI: 10.1093/ofid/ofaa439.1667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Suvratoxumab is a human monoclonal antibody that neutralizes S. aureus (SA) alpha toxin (AT). SAATELLITE, a phase 2 study of the safety and efficacy of suvratoxumab for reducing the incidence of SA pneumonia (NCT02296320), was conducted within the consortium for Combatting Bacterial Resistance in Europe.
Methods
A total of 304 SA isolates (baseline, onset and last available isolates from suspected serious bacterial infections, SSBIs) collected from the lower respiratory tract samples from 165 subjects during SAATELLITE were subjected to whole genome sequencing.
AT gene (hla) sequences were translated and amino acid variation was identified in comparison to the reference SA USA300 FPR3757. Phylogenetic analysis, genomic annotation and ST analysis were performed.
AT expression in SA culture supernatants was performed by ELISA. Representative isolates with novel AT subtypes that had not been identified in previous studies were tested for hemolytic activity and suvratoxumab neutralizing activity.
Wilcoxon rank sum test and Fisher’s exact test were performed, respectively: a) to compare difference in baseline AT expression in relation to SA pneumonia incidence; b) to evaluate the association between occurrence of AT stop codons and incidence of SA pneumonia at baseline, as well as the association between occurrence of AT stop codons and treatment arms at post baseline.
Results
We identified a total of 44 sequence types (STs) and 21 unique AT subtypes, 7 of which have not been described previously. No substitutions were located in the suvratoxumab binding region and all novel AT subtypes displaying lytic activity were neutralized by suvratoxumab.
We detected stop codons Q113B and W205B in AT sequences in 53 and 2 SA isolates, respectively. We uncovered no significant associations of: 1) baseline AT expression with SA pneumonia incidence [p=0.967]; 2) occurrence of AT gene stop codon with either SA pneumonia incidence [p >0.999] or suvratoxumab treatment [p=0.103; lower frequency of stop codons in suvratoxumab arm versus placebo].
Conclusion
Our data indicated that: 1) suvratoxumab target region in (AT) remains conserved; 2) suvratoxumab is active against all AT variants identified to date; 3) suvratoxumab did not exert pressure on SA clinical isolates for selection of escape mutants.
Disclosures
David E. Tabor, PhD, AstraZeneca (Employee, Shareholder) Andrey Tovchigrechko, PhD, AstraZeneca (Employee, Shareholder)KitePharma, a Gilead company (Employee, Shareholder) Bret R. Sellman, PhD, AstraZeneca (Employee, Shareholder) Michael McCarthy, n/a, AstraZeneca (Employee) Kathryn Shoemaker, MS, AstraZeneca (Employee) Hasan S. Jafri, MD, FAAP, AstraZeneca (Employee) Mark T. Esser, PhD, AstraZeneca (Employee) Alexey Ruzin, PhD, AstraZeneca (Employee, Shareholder)
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Affiliation(s)
| | | | | | | | | | - Pin Ren
- AstraZeneca, South San Francisco, California
| | | | | | | | | | | | | | - Basil Xavier
- University of Antwerp, Wilrijk, Antwerpen, Belgium
| | - Christine Lammens
- University Antwerp, Department of Medical Microbiology, Antwerp, Antwerpen, Belgium
| | - Herman Goossens
- University of Antwerp, Antwerp, Antwerpen, Belgium, Antwerp, Antwerpen, Belgium
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Yanjie M, Valour F, Vu Vi Tran G, Vu T, Delaye T, Quynh Nhu Nguyen T, Tkaczyk C, Cheng L, Sellman BR, An Diep B. 713. Preventive Administration of MEDI6389, a Combination of Monoclonal Antibodies (mAbs) Targeting Alpha-Toxin (AT), Panton-Valentine Leukocidin (PVL), Leukocidin ED (LukED), Gamma-Hemolysin and Clumping Factor A (ClfA), in a Rabbit Model of USA300 MRSA Prosthetic Joint Infection (PJI). Open Forum Infect Dis 2019. [PMCID: PMC6810972 DOI: 10.1093/ofid/ofz360.781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Background mAbs targeting staphylococcal virulence factors could represent an interesting preventive strategy in PJI. We evaluate here MEDI6389 compared with isotype-matched control IgG (c-IgG) in a rabbit model of USA300 MRSA PJI. Methods Rabbits were randomized for prophylaxis with either c-IgG (n = 13; 30 mg/kg; controls) or MEDI6389 (n = 13; 30 mg/kg of each mAb) administered intravenously 12h before infection. A cemented screw and ultrahigh-molecular-weight polyethylene washer were placed intraarticularly in the external femoral condyle. After suturing the joint capsule and musculocutaneous layers, 300 µL of a standardized bacterial inoculum containing 5 × 105 CFU of a USA300 MRSA clinical isolate were injected intraarticularly. Animals were euthanized on day 8 and the knee joint was harvested for bacteriological analysis (synovial bacterial counts, and enumeration of screw-adherent bacteria after sonication) and histology (conventional pathology, and transmission electron microscopy [TEM] for neutrophils analysis). In vivo observations made on neutrophils were confirmed by TEM analysis of human neutrophils incubated in vitro with purified PVL, LukED, and gamma-hemolysin with or without the corresponding mAb. Results In comparison with the control group, the average amount of pus (1.7 ± 1.8 vs. 3.1 ± 1.2 g, P = 0.026) and the number of bacteria in the synovial pus (5.9±1.5 vs. 7.2±1.4 log10 CFU, P = 0.031) and on the screw (2.7 ± 1.5 vs. 4.1 ± 1.6 log10 CFU, P = 0.035) were decreased in animals pretreated by MEDI6389. Conventional pathological examination showed a marked reduction in synovitis of MEDI6389-pretreated animals. TEM of synovitis harvested from infected knee joints of control animals showed significant greater number of abnormal neutrophils that appeared rounded, with condensed nucleus and no granules, compared with those pretreated with MEDI6389 (P = 0.002). This classical leukocidin-induced neutrophilic killing phenotype could be neutralized with anti-leukocidin mAbs using ex vivo human neutrophils incubated with PVL, LukED, HlgAB, or HlgCB. Conclusion The preventive administration of MEDI6389 allows a reduction of local inflammation and bacterial burden in this USA300 MRSA rabbit PJI model. ![]()
Disclosures All authors: No reported disclosures.
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Affiliation(s)
- Mao Yanjie
- University of California at San Francisco, San Francisco, California
| | - Florent Valour
- Infectious Disease Department, CRIOAc Lyon (Reference Center for Complex BJI Management), Claude Bernard Lyon 1 University / UCSF, Lyon, Rhone-Alpes, France
| | - Giang Vu Vi Tran
- University of California at San Francisco, San Francisco, California
| | - Trang Vu
- University of California at San Francisco, San Francisco, California
| | - Thomas Delaye
- University of California at San Francisco, San Francisco, California
| | | | | | - Li Cheng
- MedImmune LLC, Gaithersburg, Maryland
| | | | - Binh An Diep
- University of California at San Francisco, San Francisco, California
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6
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Sharma-Kuinkel BK, Tkaczyk C, Bonnell J, Yu L, Tovchigrechko A, Tabor DE, Park LP, Ruffin F, Esser MT, Sellman BR, Fowler VG, Ruzin A. Associations of pathogen-specific and host-specific characteristics with disease outcome in patients with Staphylococcus aureus bacteremic pneumonia. Clin Transl Immunology 2019; 8:e01070. [PMID: 31360464 PMCID: PMC6640002 DOI: 10.1002/cti2.1070] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 06/24/2019] [Accepted: 06/30/2019] [Indexed: 11/08/2022] Open
Abstract
Objective To understand the relationships of Staphylococcus aureus (SA) bacteremic pneumonia (SABP) outcome with patient‐specific and SA‐specific variables. Methods We analysed SA bloodstream isolates and matching sera in SABP patients by sequencing SA isolates (n = 50) and measuring in vitro AT production, haemolytic activity and expression of ClfA and ClfB. Controls were sera from gram‐negative bacteremia patients with or without pneumonia and uninfected subjects. Levels of IgGs, IgMs and neutralizing antibodies (NAbs) against SA antigens were quantified and analysed by one‐way ANOVA. Associations of patient outcomes with patient variables, antibody levels and isolate characteristics were evaluated by univariate and multivariate logistic regression analyses. Results SABP patients had higher levels of IgGs against eight virulence factors and anti‐alpha toxin (AT) NAbs than uninfected controls. Levels of IgG against AT and IgMs against ClfA, FnbpA and SdrC were higher in clinically cured SABP patients than in clinical failures. Anti‐LukAB NAb levels were elevated in all cohorts. Increased odds of cure correlated with higher haemolytic activity of SA strains, longer time between surgery and bacteremia (> 30 days), longer duration of antibiotic therapy, lower acute physiology and total APACHE II scores, lack of persistent fever for > 72 h and higher levels of antibodies against AT (IgG), ClfA (IgM), FnbpA (IgM) and SdrC (IgM). Discussion Limitations included the cross‐sectional observational nature of the study, small sample size and inability to measure antibody levels against all SA virulence factors. Conclusion Our results suggest that SABP patients may benefit from immunotherapy targeting multiple SA antigens.
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Affiliation(s)
- Batu K Sharma-Kuinkel
- Division of Infectious Diseases, Department of Medicine, Duke University Durham NC USA
| | | | | | - Li Yu
- Statistical Sciences, AstraZeneca Gaithersburg MD USA
| | | | | | - Lawrence P Park
- Division of Infectious Diseases, Department of Medicine, Duke University Durham NC USA
| | - Felicia Ruffin
- Division of Infectious Diseases, Department of Medicine, Duke University Durham NC USA
| | - Mark T Esser
- Microbial Sciences, AstraZeneca Gaithersburg MD USA
| | | | - Vance G Fowler
- Division of Infectious Diseases, Department of Medicine, Duke University Durham NC USA
| | - Alexey Ruzin
- Microbial Sciences, AstraZeneca Gaithersburg MD USA
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7
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Valour F, Yanjie M, Vu T, Tran G, Delaye T, Nguyen T, Tkaczyk C, Cheng L, Sellman B, Diep B. Immunothérapie préventive par MEDI6389, combinaison d’anticorps monoclonaux anti-alpha-toxine (AT), leucocidine de Panton-Valentine (PVL) et ED (LukED), gamma-hémolysine (HlgABC) et clumping facteur A (ClfA) dans un modèle lapin d’infection de prothèse articulaire à SARM USA300. Med Mal Infect 2019. [DOI: 10.1016/j.medmal.2019.04.218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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8
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Thompson JM, Miller RJ, Ashbaugh AG, Dillen CA, Pickett JE, Wang Y, Ortines RV, Sterling RS, Francis KP, Bernthal NM, Cohen TS, Tkaczyk C, Yu L, Stover CK, DiGiandomenico A, Sellman BR, Thorek DL, Miller LS. Mouse model of Gram-negative prosthetic joint infection reveals therapeutic targets. JCI Insight 2018; 3:121737. [PMID: 30185667 DOI: 10.1172/jci.insight.121737] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [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: 04/19/2018] [Accepted: 07/26/2018] [Indexed: 12/23/2022] Open
Abstract
Bacterial biofilm infections of implantable medical devices decrease the effectiveness of antibiotics, creating difficult-to-treat chronic infections. Prosthetic joint infections (PJI) are particularly problematic because they require prolonged antibiotic courses and reoperations to remove and replace the infected prostheses. Current models to study PJI focus on Gram-positive bacteria, but Gram-negative PJI (GN-PJI) are increasingly common and are often more difficult to treat, with worse clinical outcomes. Herein, we sought to develop a mouse model of GN-PJI to investigate the pathogenesis of these infections and identify potential therapeutic targets. An orthopedic-grade titanium implant was surgically placed in the femurs of mice, followed by infection of the knee joint with Pseudomonas aeruginosa or Escherichia coli. We found that in vitro biofilm-producing activity was associated with the development of an in vivo orthopedic implant infection characterized by bacterial infection of the bone/joint tissue, biofilm formation on the implants, reactive bone changes, and inflammatory immune cell infiltrates. In addition, a bispecific antibody targeting P. aeruginosa virulence factors (PcrV and Psl exopolysaccharide) reduced the bacterial burden in vivo. Taken together, our findings provide a preclinical model of GN-PJI and suggest the therapeutic potential of targeting biofilm-associated antigens.
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Affiliation(s)
| | | | | | | | - Julie E Pickett
- Department of Radiology and Radiological Sciences, Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Yu Wang
- Department of Dermatology, and
| | | | | | - Kevin P Francis
- PerkinElmer, Hopkinton, Massachusetts, USA.,Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Santa Monica, California, USA
| | - Nicholas M Bernthal
- Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Santa Monica, California, USA
| | | | | | - Li Yu
- Statistical Sciences, MedImmune, Gaithersburg, Maryland, USA
| | | | | | | | - Daniel Lj Thorek
- Department of Radiology and Radiological Sciences, Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Cancer Molecular and Functional Imaging Program, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, and
| | - Lloyd S Miller
- Department of Orthopaedic Surgery.,Department of Dermatology, and.,Department of Medicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
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9
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Surewaard BGJ, Thanabalasuriar A, Zeng Z, Tkaczyk C, Cohen TS, Bardoel BW, Jorch SK, Deppermann C, Bubeck Wardenburg J, Davis RP, Jenne CN, Stover KC, Sellman BR, Kubes P. α-Toxin Induces Platelet Aggregation and Liver Injury during Staphylococcus aureus Sepsis. Cell Host Microbe 2018; 24:271-284.e3. [PMID: 30033122 DOI: 10.1016/j.chom.2018.06.017] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 05/15/2018] [Accepted: 06/27/2018] [Indexed: 01/09/2023]
Abstract
During sepsis, small blood vessels can become occluded by large platelet aggregates of poorly understood etiology. During Staphylococcal aureus infection, sepsis severity is linked to the bacterial α-toxin (α-hemolysin, AT) through unclear mechanisms. In this study, we visualized intravascular events in the microcirculation and found that intravenous AT injection induces rapid platelet aggregation, forming dynamic micro-thrombi in the microcirculation. These aggregates are retained in the liver sinusoids and kidney glomeruli, causing multi-organ dysfunction. Acute staphylococcal infection results in sequestration of most bacteria by liver macrophages. Platelets are initially recruited to these macrophages and help eradicate S. aureus. However, at later time points, AT causes aberrant and damaging thrombosis throughout the liver. Treatment with an AT neutralizing antibody (MEDI4893∗) prevents platelet aggregation and subsequent liver damage, without affecting the initial and beneficial platelet recruitment. Thus, AT neutralization may represent a promising approach to combat staphylococcal-induced intravascular coagulation and organ dysfunction.
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Affiliation(s)
- Bas G J Surewaard
- Department of Physiology and Pharmacology, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada; Department of Medical Microbiology, University Medical Center, Utrecht, the Netherlands
| | - Ajitha Thanabalasuriar
- Department of Physiology and Pharmacology, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
| | - Zhutian Zeng
- Department of Physiology and Pharmacology, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
| | - Christine Tkaczyk
- Department of Microbial Sciences, Medimmune, LLC, Gaithersburg, MD, USA
| | - Taylor S Cohen
- Department of Microbial Sciences, Medimmune, LLC, Gaithersburg, MD, USA
| | - Bart W Bardoel
- Department of Medical Microbiology, University Medical Center, Utrecht, the Netherlands
| | - Selina K Jorch
- Department of Physiology and Pharmacology, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
| | - Carsten Deppermann
- Department of Physiology and Pharmacology, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
| | - Juliane Bubeck Wardenburg
- Department of Pediatrics and Division of Pediatric Critical Care Medicine at Washington University School of Medicine, St. Louis, MO, USA
| | - Rachelle P Davis
- Department of Physiology and Pharmacology, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada; Department of Microbiology, Immunology and Infectious Disease, University of Calgary, Calgary, AB, Canada
| | - Craig N Jenne
- Department of Physiology and Pharmacology, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada; Department of Microbiology, Immunology and Infectious Disease, University of Calgary, Calgary, AB, Canada
| | - Kendall C Stover
- Department of Microbial Sciences, Medimmune, LLC, Gaithersburg, MD, USA
| | - Bret R Sellman
- Department of Microbial Sciences, Medimmune, LLC, Gaithersburg, MD, USA
| | - Paul Kubes
- Department of Physiology and Pharmacology, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.
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10
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Ortines R, Liu H, Cheng L, Cohen T, Lawlor H, Gami A, Wang Y, Dillen C, Archer N, Miller R, Ashbaugh A, Pinsker B, Marchitto M, Tkaczyk C, Stover C, Sellman B, Miller L. 1431 Neutralizing α-toxin accelerates healing of Staphylococcus aureus-infected wounds in normal and diabetic mice. J Invest Dermatol 2018. [DOI: 10.1016/j.jid.2018.03.1449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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11
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Ruzin A, Wu Y, Yu L, Yu XQ, Tabor DE, Mok H, Tkaczyk C, Jensen K, Bellamy T, Roskos L, Esser MT, Jafri HS. Characterisation of anti-alpha toxin antibody levels and colonisation status after administration of an investigational human monoclonal antibody, MEDI4893, against Staphylococcus aureus alpha toxin. Clin Transl Immunology 2018; 7:e1009. [PMID: 29484186 PMCID: PMC5822409 DOI: 10.1002/cti2.1009] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 12/20/2017] [Accepted: 12/29/2017] [Indexed: 01/07/2023] Open
Abstract
Objectives MEDI4893 is a novel, long‐acting human monoclonal antibody targeting Staphylococcus aureus (SA) alpha toxin (AT). This report presents the results of the exploratory analyses from a randomised phase 1 dose‐escalation study in healthy human subjects receiving single intravenous MEDI4893 doses or placebo. Methods Anti‐AT antibodies and AT expression were measured as described previously. Nasal swabs were analysed by culture and PCR. Data were summarised by treatment groups and visits by using SAS System Version 9.3. Results Subjects receiving 2250 or 5000 mg of MEDI4893 had the highest serum anti‐AT neutralising antibody (NAb) levels: approximately 180‐ to 240‐, 70‐ to 100‐ and sevenfold to 10‐fold higher than respective baseline levels at peak, 30 and 360 days, respectively. In these subjects, levels of serum anti‐AT NAbs were >3.2 International Units (IU) mL−1 for at least 211 days. In the upper respiratory tract, anti‐AT NAb levels increased with MEDI4893 dose. No apparent effect of MEDI4893 on SA nasal colonisation, hla gene sequence or AT expression was observed. Five AT variants were detected, their lytic activity was fully neutralised by MEDI4893. Discussion Our results indicate that (1) MEDI4893 administration at 2250 and 5000 mg would provide effective immunoprophylaxis against systemic SA disease; (2) MEDI4983 distributes to the upper respiratory tract and retains neutralising activity against AT; and (3) potential for emergence of MEDI4893 resistance is low. Conclusion Intravenous administration of MEDI4893 maintained levels of anti‐AT NAbs in serum and nasal mucosa that may provide effective immunoprophylaxis against SA disease and support continued clinical development of MEDI4893.
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Affiliation(s)
| | | | - Li Yu
- MedImmune Gaithersburg MD USA
| | - Xiang-Qing Yu
- MedImmune Gaithersburg MD USA.,Present address: Janssen Pharmaceuticals, Inc. Johnson & Johnson Spring House PA USA
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12
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Diep BA, Le VTM, Badiou C, Le HN, Pinheiro MG, Duong AH, Wang X, Dip EC, Aguiar-Alves F, Basuino L, Marbach H, Mai TT, Sarda MN, Kajikawa O, Matute-Bello G, Tkaczyk C, Rasigade JP, Sellman BR, Chambers HF, Lina G. IVIG-mediated protection against necrotizing pneumonia caused by MRSA. Sci Transl Med 2017; 8:357ra124. [PMID: 27655850 DOI: 10.1126/scitranslmed.aag1153] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 09/02/2016] [Indexed: 12/12/2022]
Abstract
New therapeutic approaches are urgently needed to improve survival outcomes for patients with necrotizing pneumonia caused by Staphylococcus aureus One such approach is adjunctive treatment with intravenous immunoglobulin (IVIG), but clinical practice guidelines offer conflicting recommendations. In a preclinical rabbit model, prophylaxis with IVIG conferred protection against necrotizing pneumonia caused by five different epidemic strains of community-associated methicillin-resistant S. aureus (MRSA) as well as a widespread strain of hospital-associated MRSA. Treatment with IVIG, either alone or in combination with vancomycin or linezolid, improved survival outcomes in this rabbit model. Two specific IVIG antibodies that neutralized the toxic effects of α-hemolysin (Hla) and Panton-Valentine leukocidin (PVL) conferred protection against necrotizing pneumonia in the rabbit model. This mechanism of action of IVIG was uncovered by analyzing loss-of-function mutant bacterial strains containing deletions in 17 genes encoding staphylococcal exotoxins, which revealed only Hla and PVL as having an impact on necrotizing pneumonia. These results demonstrate the potential clinical utility of IVIG in the treatment of severe pneumonia induced by S. aureus.
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Affiliation(s)
- Binh An Diep
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA.
| | - Vien T M Le
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Cedric Badiou
- INSERM U1111, Université Lyon 1, CNRS UMR5308, ENS Lyon, Lyon, France. Centre National de Référence des Staphylocoques, Hospices Civils de Lyon, Bron, France
| | - Hoan N Le
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Marcos Gabriel Pinheiro
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA. Pathology Program, Fluminense Federal University, Niterói, RJ, Brazil
| | - Au H Duong
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Xing Wang
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Etyene Castro Dip
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Fábio Aguiar-Alves
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA. Pathology Program, Fluminense Federal University, Niterói, RJ, Brazil
| | - Li Basuino
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Helene Marbach
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Thuy T Mai
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Marie N Sarda
- Laboratory of Immunology, Centre Hospitalier Lyon Sud, Hospices Civils de Lyon, Lyon, France
| | - Osamu Kajikawa
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98109, USA
| | - Gustavo Matute-Bello
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98109, USA
| | - Christine Tkaczyk
- Department of Infectious Diseases, MedImmune, LLC, Gaithersburg, MD 20878, USA
| | - Jean-Philippe Rasigade
- INSERM U1111, Université Lyon 1, CNRS UMR5308, ENS Lyon, Lyon, France. Centre National de Référence des Staphylocoques, Hospices Civils de Lyon, Bron, France
| | - Bret R Sellman
- Department of Infectious Diseases, MedImmune, LLC, Gaithersburg, MD 20878, USA
| | - Henry F Chambers
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Gerard Lina
- INSERM U1111, Université Lyon 1, CNRS UMR5308, ENS Lyon, Lyon, France. Centre National de Référence des Staphylocoques, Hospices Civils de Lyon, Bron, France.
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13
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WANG YU, Cheng L, Helfer DR, Ashbaugh AG, Miller RJ, Tzomides AJ, Thompson JM, Ortines RV, Tsai AS, Liu H, Dillen C, Archer N, Cohen TS, Tkaczyk C, Sellman BR, Miller LS. Staphylococcus aureus alpha-toxin and Clumping Factor A are pathogenic and immunotherapeutic targets against a hematogenous implant-related biofilm infection. The Journal of Immunology 2017. [DOI: 10.4049/jimmunol.198.supp.57.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
Infection is a major impediment to the long-term success of implantable medical devices. Treatment of these infections is complicated by bacteria biofilms, which form on the implants and block penetration of immune cells and antibiotics. Hematogenous implant-related infections following a transient bacteremia are particularly problematic because they can occur at any time in a previously stable implant. To evaluate alternative targeted immune-based therapies against these infections, we developed a hematogenous infection model in which an orthopaedic titanium implant was surgically placed in the legs of mice followed by an intravenous injection of Staphylococcus aureus 21 days later. This resulted in a marked propensity for a hematogenous implant-related infection comprised of septic arthritis, osteomyelitis with neutrophil abscess formation in the bone and biofilm formation on the implants in the surgical legs compared with sham surgical legs without implant placement or contralateral nonsurgical normal legs. Prophylaxis with two neutralizing human monoclonal antibodies directed against S. aureus virulence factors, secreted alpha-toxin (AT) and surface expressed clumping factor A (ClfA) inhibited biofilm formation in vitro and the hematogenous implant-related infection in vivo. Our findings suggest that AT and ClfA are important pathogenic factors that could be targeted as a novel immunotherapeutic against S. aureus hematogenous implant-related infections.
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Affiliation(s)
- YU WANG
- 1Department of Dermatology, Johns Hopkins University School of Medicine
| | - Lily Cheng
- 2Department of Translational Science, MedImmune, LLC
| | - David R Helfer
- 1Department of Dermatology, Johns Hopkins University School of Medicine
| | - Alyssa G Ashbaugh
- 1Department of Dermatology, Johns Hopkins University School of Medicine
| | - Robert J Miller
- 1Department of Dermatology, Johns Hopkins University School of Medicine
| | | | - John M Thompson
- 3Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine
| | - Roger V Ortines
- 1Department of Dermatology, Johns Hopkins University School of Medicine
| | - Andrew S Tsai
- 1Department of Dermatology, Johns Hopkins University School of Medicine
| | - Haiyun Liu
- 1Department of Dermatology, Johns Hopkins University School of Medicine
| | - Carly Dillen
- 1Department of Dermatology, Johns Hopkins University School of Medicine
| | - Nathan Archer
- 1Department of Dermatology, Johns Hopkins University School of Medicine
| | | | | | | | - Lloyd S Miller
- 1Department of Dermatology, Johns Hopkins University School of Medicine
- 3Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine
- 5Department of Mdicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine
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14
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Ortines RV, Cheng L, Cohen TS, Gami A, Dillen CA, Ashbaugh AG, Miller RJ, Wang Y, Tkaczyk C, Sellman BR, Miller LS. Anti-alpha-toxin immunoprohylaxis reduces disease severity against a Staphylococcus aureus full-thickness skin wound infection in immunocompetent and diabetic mice. The Journal of Immunology 2017. [DOI: 10.4049/jimmunol.198.supp.77.20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Staphylococcus aureus infection is a major complication of acute and chronic skin wounds that delays wound closure and healing. These infections are particularly problematic in diabetic foot ulcers as the infection can become invasive, leading to osteomyelitis that often necessitates limb amputation. Prior reports in S. aureus skin infection models have indicated that neutralizing S. aureus alpha-toxin decreases disease severity by reducing skin lesion size and restoring an appropriate host immune response, however whether alpha-toxin neutralization impacts S. aureus-infected skin wounds is not clear, especially in the setting of diabetes. Herein, we evaluated the efficacy of MEDI4893* a neutralizing human anti-alpha-toxin monoclonal antibody (mAb) in a S. aureus skin wound infection model. Three full-thickness cuts were made on the back skin of wildtype (wt) C57BL/6 and diabetic (TallyHo) mice and the cuts inoculated with a bioluminescent methicillin-resistant S. aureus (MRSA) strain. In both WT and diabetic mice, prophylaxis with MEDI4893* resulted in a significant reduction in skin lesion sizes, decreased bacterial burden, improved re-epithelialization, and a decreased percentage of neutrophils and an increased percentage of macrophages in the skin compared with control mAb treatment. Thus, in S. aureus-infected skin wounds, anti-alpha-toxin mAb treatment reduced disease severity by not only inhibiting dermonecrosis but also by resolving neutrophilic inflammation.
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Affiliation(s)
| | - Lily Cheng
- 2Department of Translational Science, MedImmune, LLC
| | | | - Abhishek Gami
- 1Department of Dermatology, Johns Hopkins University School of Medicine
| | - Carly A Dillen
- 1Department of Dermatology, Johns Hopkins University School of Medicine
| | - Alyssa G Ashbaugh
- 1Department of Dermatology, Johns Hopkins University School of Medicine
| | - Robert J Miller
- 1Department of Dermatology, Johns Hopkins University School of Medicine
| | - Yu Wang
- 1Department of Dermatology, Johns Hopkins University School of Medicine
| | | | | | - Lloyd S Miller
- 1Department of Dermatology, Johns Hopkins University School of Medicine
- 4Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine
- 5Department of Medicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine
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15
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Le VTM, Le HN, Pinheiro MG, Hahn KJ, Dinh ML, Larson KB, Flanagan SD, Badiou C, Lina G, Tkaczyk C, Sellman BR, Diep BA. Effects of Tedizolid Phosphate on Survival Outcomes and Suppression of Production of Staphylococcal Toxins in a Rabbit Model of Methicillin-Resistant Staphylococcus aureus Necrotizing Pneumonia. Antimicrob Agents Chemother 2017; 61:e02734-16. [PMID: 28137816 PMCID: PMC5365717 DOI: 10.1128/aac.02734-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Accepted: 01/24/2017] [Indexed: 01/30/2023] Open
Abstract
The protective efficacy of tedizolid phosphate, a novel oxazolidinone that potently inhibits bacterial protein synthesis, was compared to those of linezolid, vancomycin, and saline in a rabbit model of Staphylococcus aureus necrotizing pneumonia. Tedizolid phosphate was administered to rabbits at 6 mg/kg of body weight intravenously twice daily, which yielded values of the 24-h area under the concentration-time curve approximating those found in humans. The overall survival rate was 83% for rabbits treated with 6 mg/kg tedizolid phosphate twice daily and 83% for those treated with 50 mg/kg linezolid thrice daily (P = 0.66 by the log-rank test versus the results obtained with tedizolid phosphate). These survival rates were significantly greater than the survival rates of 17% for rabbits treated with 30 mg/kg vancomycin twice daily (P = 0.003) and 17% for rabbits treated with saline (P = 0.002). The bacterial count in the lungs of rabbits treated with tedizolid phosphate was significantly decreased compared to that in the lungs of rabbits treated with saline, although it was not significantly different from that in the lungs of rabbits treated with vancomycin or linezolid. The in vivo bacterial production of alpha-toxin and Panton-Valentine leukocidin, two key S. aureus-secreted toxins that play critical roles in the pathogenesis of necrotizing pneumonia, in the lungs of rabbits treated with tedizolid phosphate and linezolid was significantly inhibited compared to that in the lungs of rabbits treated with vancomycin or saline. Taken together, these results indicate that tedizolid phosphate is superior to vancomycin for the treatment of S. aureus necrotizing pneumonia because it inhibits the bacterial production of lung-damaging toxins at the site of infection.
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Affiliation(s)
- Vien T M Le
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, California, USA
| | - Hoan N Le
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, California, USA
| | - Marcos Gabriel Pinheiro
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, California, USA
| | - Kenneth J Hahn
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, California, USA
| | - Mary L Dinh
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, California, USA
| | | | | | - Cedric Badiou
- INSERM U1111, Université Lyon 1, CNRS UMR5308, ENS Lyon, Lyon, France
- Centre National de Référence des Staphylocoques, Hospices Civils de Lyon, Bron, France
| | - Gerard Lina
- INSERM U1111, Université Lyon 1, CNRS UMR5308, ENS Lyon, Lyon, France
- Centre National de Référence des Staphylocoques, Hospices Civils de Lyon, Bron, France
| | - Christine Tkaczyk
- Department of Infectious Diseases, MedImmune, Gaithersburg, Maryland, USA
| | - Bret R Sellman
- Department of Infectious Diseases, MedImmune, Gaithersburg, Maryland, USA
| | - Binh An Diep
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco, California, USA
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16
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Cohen TS, Hilliard JJ, Jones-Nelson O, Keller AE, O'Day T, Tkaczyk C, DiGiandomenico A, Hamilton M, Pelletier M, Wang Q, Diep BA, Le VTM, Cheng L, Suzich J, Stover CK, Sellman BR. Staphylococcus aureus α toxin potentiates opportunistic bacterial lung infections. Sci Transl Med 2016; 8:329ra31. [PMID: 26962155 DOI: 10.1126/scitranslmed.aad9922] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Broad-spectrum antibiotic use may adversely affect a patient's beneficial microbiome and fuel cross-species spread of drug resistance. Although alternative pathogen-specific approaches are rationally justified, a major concern for this precision medicine strategy is that co-colonizing or co-infecting opportunistic bacteria may still cause serious disease. In a mixed-pathogen lung infection model, we find that the Staphylococcus aureus virulence factor α toxin potentiates Gram-negative bacterial proliferation, systemic spread, and lethality by preventing acidification of bacteria-containing macrophage phagosomes, thereby reducing effective killing of both S. aureus and Gram-negative bacteria. Prophylaxis or early treatment with a single α toxin neutralizing monoclonal antibody prevented proliferation of co-infecting Gram-negative pathogens and lethality while also promoting S. aureus clearance. These studies suggest that some pathogen-specific, antibody-based approaches may also work to reduce infection risk in patients colonized or co-infected with S. aureus and disparate drug-resistant Gram-negative bacterial opportunists.
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Affiliation(s)
- Taylor S Cohen
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Jamese J Hilliard
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Omari Jones-Nelson
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Ashley E Keller
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Terrence O'Day
- Department of Translational Science, MedImmune, Gaithersburg, MD 20878, USA
| | - Christine Tkaczyk
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | | | - Melissa Hamilton
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Mark Pelletier
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Qun Wang
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Binh An Diep
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA. Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Vien T M Le
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Lily Cheng
- Department of Translational Science, MedImmune, Gaithersburg, MD 20878, USA
| | - JoAnn Suzich
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - C Kendall Stover
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA
| | - Bret R Sellman
- Department of Infectious Disease, MedImmune, Gaithersburg, MD 20878, USA.
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17
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Bhoi P, Bessette L, Bell M, Tkaczyk C, Nantel F, Maslova K. AB1040 Comparison of Adherence and Dosing Interval of Subcutaneous anti-TNF Biologics in Inflammatory Arthritis from A Canadian Administrative Database. Ann Rheum Dis 2016. [DOI: 10.1136/annrheumdis-2016-eular.3760] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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18
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Kelsall J, Choquette D, Rahman P, Arendse R, Teo M, Fortin I, Avina-Zubieta J, Rampakakis E, Psaradellis E, Maslova K, Osborne B, Tkaczyk C, Nantel F, Lehman A. FRI0421 What Is The Location of Enthesitis in Ankylosing Spondylitis and Psoriatic Arthritis Patients and How Do They Respond To Anti-TNF Treatment?: Table 1. Ann Rheum Dis 2016. [DOI: 10.1136/annrheumdis-2016-eular.3753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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19
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Arendse R, Haraoui B, Choquette D, Kelsall J, Baer P, Sholter D, Bensen W, Bell M, Teo M, Rampakakis E, Psaradellis E, Osborne B, Tkaczyk C, Maslova K, Nantel F, Lehman A. FRI0579 What Is The Variability of HAQ over Time in Patients with Rheumatoid Arthritis Treated with Anti-TNF? Ann Rheum Dis 2016. [DOI: 10.1136/annrheumdis-2016-eular.4273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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20
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Keystone E, Baer P, Olszynski W, Baker M, Haraoui B, Bensen W, Faraawi R, Rampakakis E, Sampalis J, Lehman A, Nantel F, Osborne B, Tkaczyk C, Maslova K. FRI0172 Primary and Secondary Non-Response in RA Patients Treated with An anti-TNF: An Analysis from A Prospective, Observational Registry. Ann Rheum Dis 2016. [DOI: 10.1136/annrheumdis-2016-eular.3766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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21
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Arendse R, Rahman P, Avina-Zubieta J, Choquette D, Zummer M, Baker M, Stewart J, Fortin I, Teo M, Rampakakis E, Psaradellis E, Osborne B, Tkaczyk C, Maslova K, Nantel F, Lehman A. FRI0429 What Is The Location of Dactylitis in Ankylosing Spondylitis and Psoriatic Arthritis Patients and How Do They Respond To Anti-TNF Treatment?: Table 1. Ann Rheum Dis 2016. [DOI: 10.1136/annrheumdis-2016-eular.4255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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22
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Tabor DE, Yu L, Mok H, Sellman B, Tkaczyk C, Wu Y, Oganesyan V, Jafri H, Mccarthy M, Slidel T, Bradford P, Esser MT. Staphylococcus aureus Alpha Toxin Expression is Highly Conserved in MSSA and MRSA Hospital Respiratory Isolates Collected From an International Surveillance Study. Open Forum Infect Dis 2015. [DOI: 10.1093/ofid/ofv133.588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Xiao X, Chen Y, Mugabe S, Gao C, Tkaczyk C, Mazor Y, Pavlik P, Wu H, Dall’Acqua W, Chowdhury PS. A Novel Dual Expression Platform for High Throughput Functional Screening of Phage Libraries in Product like Format. PLoS One 2015; 10:e0140691. [PMID: 26468955 PMCID: PMC4607404 DOI: 10.1371/journal.pone.0140691] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 09/28/2015] [Indexed: 11/18/2022] Open
Abstract
High throughput screenings of single chain Fv (scFv) antibody phage display libraries are currently done as soluble scFvs produced in E.coli. Due to endotoxin contaminations from bacterial cells these preparations cannot be reliably used in mammalian cell based assays. The monovalent nature and lack of Fc in soluble scFvs prevent functional assays that are dependent on target cross linking and/or Fc functions. A convenient approach is to convert scFvs into scFv.Fc fusion proteins and express them in mammalian cell lines for screening. This approach is low throughput and is only taken after primary screening of monovalent scFvs that are expressed in bacteria. There is no platform at present that combines the benefits of both bacterial and mammalian expression system for screening phage library output. We have, therefore, developed a novel dual expression vector, called pSplice, which can be used to express scFv.Fc fusion proteins both in E.coli and mammalian cell lines. The hallmark of the vector is an engineered intron which houses the bacterial promoter and signal peptide for expression and secretion of scFv.Fc in E.coli. When the vector is transfected into a mammalian cell line, the intron is efficiently spliced out resulting in a functional operon for expression and secretion of the scFv.Fc fusion protein into the culture medium. By applying basic knowledge of mammalian introns and splisosome, we designed this vector to enable screening of phage libraries in a product like format. Like IgG, the scFv.Fc fusion protein is bi-valent for the antigen and possesses Fc effector functions. Expression in E.coli maintains the speed of the bacterial expression platform and is used to triage clones based on binding and other assays that are not sensitive to endotoxin. Triaged clones are then expressed in a mammalian cell line without the need for any additional cloning steps. Conditioned media from the mammalian cell line containing the fusion proteins are then used for different types of cell based assays. Thus this system retains the speed of the current screening system for phage libraries and adds additional functionality to it.
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Affiliation(s)
- Xiaodong Xiao
- Dept. of Antibody Discovery and Protein Engineering, MedImmune, LLC., Gaithersburg, MD, 20878, United States of America
| | - Yan Chen
- Dept. of Antibody Discovery and Protein Engineering, MedImmune, LLC., Gaithersburg, MD, 20878, United States of America
| | - Sheila Mugabe
- Dept. of Biopharmaceutical Development, MedImmune, LLC., Gaithersburg, MD, 20878, United States of America
| | - Changshou Gao
- Dept. of Antibody Discovery and Protein Engineering, MedImmune, LLC., Gaithersburg, MD, 20878, United States of America
| | - Christine Tkaczyk
- Dept. of Infectious Diseases, MedImmune, LLC., Gaithersburg, MD, 20878, United States of America
| | - Yariv Mazor
- Dept. of Antibody Discovery and Protein Engineering, MedImmune, LLC., Gaithersburg, MD, 20878, United States of America
| | - Peter Pavlik
- Dept. of Antibody Discovery and Protein Engineering, MedImmune, LLC., Gaithersburg, MD, 20878, United States of America
| | - Herren Wu
- Dept. of Antibody Discovery and Protein Engineering, MedImmune, LLC., Gaithersburg, MD, 20878, United States of America
| | - William Dall’Acqua
- Dept. of Antibody Discovery and Protein Engineering, MedImmune, LLC., Gaithersburg, MD, 20878, United States of America
| | - Partha Sarathi Chowdhury
- Dept. of Antibody Discovery and Protein Engineering, MedImmune, LLC., Gaithersburg, MD, 20878, United States of America
- * E-mail:
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Chow A, Bensen W, Arendse R, Keystone E, Baer P, Kelsall J, Olszynski W, Rodrigues J, Avina-Zubieta A, Baker M, Olszynski W, Bensen W, Baer P, Choquette D, Kapur S, Jaroszynska A, Sampalis J, Choquette D, Rampakakis E, Kapur S, Stewart J, Tkaczyk C, Sampalis J, Shawi M, Rampakakis E, Lehman A, Nantel F, Otawa S, Tkaczyk C, Lehman A. SAT0062 What is the Effect of TNF Inhibitors on Employment Status in Rheumatoid Arthritis Patients and what are the Predictors of Progression to Unemployment? Ann Rheum Dis 2015. [DOI: 10.1136/annrheumdis-2015-eular.6199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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25
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Rahman P, Zummer M, Olszynski W, Khraishi M, Sholter D, Faraawi R, Bensen W, Baker M, Chow A, Vaillancourt J, Sampalis J, Nantel F, Otawa S, Lehman A, Tkaczyk C, Shawi M. FRI0204 What is the Correlation of Individual HAQ and Basdai Questions with Disease Activity Measures in Ankylosing Spondylitis? Implications for Instrument Reduction. Ann Rheum Dis 2015. [DOI: 10.1136/annrheumdis-2015-eular.2821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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26
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Sholter D, Olszynski W, Baer P, Sheriff M, Dixit S, Chow A, Haraoui B, Choquette D, Kelsall J, Sampalis J, Rampakakis E, Nantel F, Tkaczyk C, Lehman A. SAT0338 Does Treatment Improve HAQ or Do Patients Adjust How They Do Things? An Exploration of the HAQ-DI Vs the HAQ-ADI Over Time. Ann Rheum Dis 2015. [DOI: 10.1136/annrheumdis-2015-eular.3529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Faraawi R, Dixit S, Mulgund M, Bensen W, Kelsall J, Choquette D, Baker M, Fortin I, Sampalis J, Rampakakis E, Tkaczyk C, Lehman A, Nantel F. AB1163 Prevalence of Smoking and Impact on Disease Parameters Among Ankylosing Spondylitis, Rheumatoid Arthritis and Psoriatic Arthritis Patients Treated with Infliximab or Golimumab. Ann Rheum Dis 2015. [DOI: 10.1136/annrheumdis-2015-eular.2374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Rahman P, Jovaisas A, Bensen W, Olszynski W, Jaroszynska A, Baer P, Sheriff M, Sholter D, Psaradellis E, Sampalis J, Nantel F, Otawa S, Lehman A, Tkaczyk C, Shawi M. THU0196 Is the Basdai Score Driven by Pain in Ankylosing Spondylitis Patients Treated with Anti-TNF? Ann Rheum Dis 2015. [DOI: 10.1136/annrheumdis-2015-eular.2812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Faraawi R, Joshi R, Bensen W, Choquette D, Olszynski W, Arendse R, Sheriff M, Rahman P, Sampalis J, Rampakakis E, Tkaczyk C, Nantel F. SAT0168 What is the Treatment Durability and Safety Profile of Rheumatoid Arthritis Patients Treated with Infliximab Plus Methotrexate and/or Leflunomide? An Analysis from a Real-World Registry. Ann Rheum Dis 2015. [DOI: 10.1136/annrheumdis-2015-eular.2402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Arendse R, Kelsall J, Avina-Zubieta A, Baer P, Rodrigues J, Jovaisas A, Fortin I, Sheriff M, Khraishi M, Rampakakis E, Sampalis J, Nantel F, Shawi M, Tkaczyk C, Otawa S, Lehman A. THU0365 Do Patterns of Joint Swelling or Tenderness in Rheumatoid Arthritis Patients Impact Disease Activity Outcomes and Pain? Implications for Clinical Practice. Ann Rheum Dis 2015. [DOI: 10.1136/annrheumdis-2015-eular.3525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Bensen W, Keystone E, Baer P, Rodrigues J, Avina-Zubieta A, Olszynski W, Choquette D, Kapur S, Sampalis J, Rampakakis E, Tkaczyk C, Shawi M, Lehman A, Nantel F, Otawa S. SAT0090 Exploring The Das: What is the Level of Agreement in the Classification of Remission and Low Disease Activity Among the Various Versions of the Disease Activity Score (DAS) and Their Correlation? An Analysis from a Prospective, Observational Registry. Ann Rheum Dis 2015. [DOI: 10.1136/annrheumdis-2015-eular.2399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Choquette D, Thorne C, Khraishi M, Fortin I, Arendse R, Chow A, Kelsall J, Baker M, Vaillancourt J, Sampalis J, Nantel F, Otawa S, Lehman A, Tkaczyk C, Shawi M. SAT0565 Correlation of Individual HAQ Questions with Disease Activity Measures in Psoriatic Arthritis: Implications for Instrument Reduction. Ann Rheum Dis 2015. [DOI: 10.1136/annrheumdis-2015-eular.2796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Keystone E, Baer P, Avina-Zubieta A, Jaroszynska A, Rodrigues J, Arendse R, Sholter D, Starr M, Masetto A, Sampalis J, Rampakakis E, Tkaczyk C, Shawi M, Lehman A, Nantel F, Otawa S. FRI0036 What is the Level of Agreement Between Disease Activity Indices and Response Criteria Among Rheumatoid Arthritis Patients Treated with TNF Inhibitors? Ann Rheum Dis 2015. [DOI: 10.1136/annrheumdis-2015-eular.2389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Baer P, Keystone E, Bensen W, Thorne C, Haraoui B, Choquette D, Arendse R, Kelsall J, Sheriff M, Sampalis J, Rampakakis E, Tkaczyk C, Shawi M, Lehman A, Nantel F, Otawa S. AB0304 What Proportion of Patients Fail to Achieve Das, Cdai, Sdai Remission Based on Patient Global assessment? An Analysis from a Prospective, Observational Registry. Ann Rheum Dis 2015. [DOI: 10.1136/annrheumdis-2015-eular.2364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Sholter D, Kelsall J, Arendse R, Avina-Zubieta A, Bensen W, Zummer M, Faraawi R, Dixit S, Khraishi M, Fortin I, Sampalis J, Psaradellis E, Nantel F, Tkaczyk C, Lehman A. SAT0557 Predictors of Response in Patients with Psoriatic Arthritis Treated with Anti-TNF in a Real-World Setting. Ann Rheum Dis 2015. [DOI: 10.1136/annrheumdis-2015-eular.3538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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36
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Oganesyan V, Peng L, Damschroder MM, Cheng L, Sadowska A, Tkaczyk C, Sellman BR, Wu H, Dall'Acqua WF. Mechanisms of neutralization of a human anti-α-toxin antibody. J Biol Chem 2014; 289:29874-80. [PMID: 25210036 PMCID: PMC4207998 DOI: 10.1074/jbc.m114.601328] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
MEDI4893 is a neutralizing human monoclonal antibody that targets α-toxin (AT) and is currently undergoing evaluation in the field of Staphylococcus aureus-mediated diseases. We have solved the crystal structure of MEDI4893 Fab bound to monomeric AT at a resolution of 2.56 Å and further characterized its epitope using various engineered AT variants. We have found that MEDI4893 recognizes a novel epitope in the so-called “rim” domain of AT and exerts its neutralizing effect through a dual mechanism. In particular, MEDI4893 not only sterically blocks binding of AT to its cell receptor but also prevents it from adopting a lytic heptameric trans-membrane conformation.
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Affiliation(s)
- Vaheh Oganesyan
- From the Departments of Antibody Discovery and Protein Engineering and
| | - Li Peng
- From the Departments of Antibody Discovery and Protein Engineering and
| | | | - Li Cheng
- From the Departments of Antibody Discovery and Protein Engineering and
| | | | | | - Bret R Sellman
- Infectious Diseases, MedImmune, Gaithersburg, Maryland 20878
| | - Herren Wu
- From the Departments of Antibody Discovery and Protein Engineering and
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Tkaczyk C, Hamilton MM, Datta V, Yang XP, Hilliard JJ, Stephens GL, Sadowska A, Hua L, O’Day T, Suzich J, Stover CK, Sellman BR. Staphylococcus aureus alpha toxin suppresses effective innate and adaptive immune responses in a murine dermonecrosis model. PLoS One 2013; 8:e75103. [PMID: 24098366 PMCID: PMC3788755 DOI: 10.1371/journal.pone.0075103] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 08/09/2013] [Indexed: 12/18/2022] Open
Abstract
An optimal host response against Staphylococcus aureus skin and soft tissue infections (SSTI) is dependent on IL-1β and IL-17 mediated abscess formation. Alpha toxin (AT), an essential virulence factor for SSTI, has been reported to damage tissue integrity; however its effect on the immune response has not been investigated. Here, we demonstrate that infection with USA300 AT isogenic mutant (Δhla), or passive immunization with an AT neutralizing mAb, 2A3, 24 h prior to infection with wild type USA300 (WT), resulted in dermonecrotic lesion size reduction, and robust neutrophil infiltration. Infiltration correlates with increase in proinflammatory cytokines and chemokines, as well as enhanced bacterial clearance relative to immunization with a negative control mAb. In addition, infection with Δhla, or with WT +2A3, resulted in an early influx of innate IL-17+γδT cells and a more rapid induction of an adaptive immune response as measured by Th1 and Th17 cell recruitment at the site of infection. These results are the first direct evidence of a role for AT in subverting the innate and adaptive immune responses during a S. aureus SSTI. Further, these effects of AT can be overcome with a high affinity anti-AT mAb resulting in a reduction in disease severity.
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Affiliation(s)
- Christine Tkaczyk
- Department of Infectious Disease, MedImmune, LLC, Gaithersburg, Maryland, United States of America
| | - Melissa M. Hamilton
- Department of Infectious Disease, MedImmune, LLC, Gaithersburg, Maryland, United States of America
| | - Vivekananda Datta
- Pathology Department, MedImmune, LLC, Gaithersburg, Maryland, United States of America
| | - Xiang Ping Yang
- Department of Respiratory, Inflammatory and Autoimmune Diseases, MedImmune, LLC, Gaithersburg, Maryland, United States of America
| | - Jamese J. Hilliard
- Department of Infectious Disease, MedImmune, LLC, Gaithersburg, Maryland, United States of America
| | - Geoffrey L. Stephens
- Department of Respiratory, Inflammatory and Autoimmune Diseases, MedImmune, LLC, Gaithersburg, Maryland, United States of America
| | - Agnieszka Sadowska
- Department of Infectious Disease, MedImmune, LLC, Gaithersburg, Maryland, United States of America
| | - Lei Hua
- Department of Infectious Disease, MedImmune, LLC, Gaithersburg, Maryland, United States of America
| | - Terrence O’Day
- Biostatistics Department, MedImmune, LLC, Gaithersburg, Maryland, United States of America
| | - JoAnn Suzich
- Department of Infectious Disease, MedImmune, LLC, Gaithersburg, Maryland, United States of America
| | - Charles Kendall Stover
- Department of Infectious Disease, MedImmune, LLC, Gaithersburg, Maryland, United States of America
| | - Bret R. Sellman
- Department of Infectious Disease, MedImmune, LLC, Gaithersburg, Maryland, United States of America
- * E-mail:
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Chan-Chan LH, Tkaczyk C, Vargas-Coronado RF, Cervantes-Uc JM, Tabrizian M, Cauich-Rodriguez JV. Characterization and biocompatibility studies of new degradable poly(urea)urethanes prepared with arginine, glycine or aspartic acid as chain extenders. J Mater Sci Mater Med 2013; 24:1733-1744. [PMID: 23615787 DOI: 10.1007/s10856-013-4931-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 04/13/2013] [Indexed: 06/02/2023]
Abstract
Polyurethanes are very often used in the cardiovascular field due to their tunable physicochemical properties and acceptable hemocompatibility although they suffer from poor endothelialization. With this in mind, we proposed the synthesis of a family of degradable segmented poly(urea)urethanes (SPUUs) using amino acids (L-arginine, glycine and L-aspartic acid) as chain extenders. These polymers degraded slowly in PBS (pH 7.4) after 24 weeks via a gradual decrease in molecular weight. In contrast, accelerated degradation showed higher mass loss under acidic, alkaline and oxidative media. MTT tests on polyurethanes with L-arginine as chain extenders showed no adverse effect on the metabolism of human umbilical vein endothelial cells (HUVECs) indicating the leachables did not provoke any toxic responses. In addition, SPUUs containing L-arginine promoted higher levels of HUVECs adhesion, spreading and viability after 7 days compared to the commonly used Tecoflex(®) polyurethane. The biodegradability and HUVEC proliferation on L-arginine-based SPUUs suggests that they can be used in the design of vascular grafts for tissue engineering.
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Affiliation(s)
- L H Chan-Chan
- Centro de Investigación Científica de Yucatán A. C., Calle 43 # 130 Col. Chuburná de Hidalgo, C.P.97200, Mérida, Yucatán, Mexico
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Diep BA, Afasizheva A, Le HN, Kajikawa O, Matute-Bello G, Tkaczyk C, Sellman B, Badiou C, Lina G, Chambers HF. Effects of linezolid on suppressing in vivo production of staphylococcal toxins and improving survival outcomes in a rabbit model of methicillin-resistant Staphylococcus aureus necrotizing pneumonia. J Infect Dis 2013; 208:75-82. [PMID: 23532096 DOI: 10.1093/infdis/jit129] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Linezolid is recommended for treatment of pneumonia and other invasive infections caused by methicillin-resistant Staphylococcus aureus (MRSA). The premise underlying this recommendation is that linezolid inhibits in vivo production of potent staphylococcal exotoxins, including Panton-Valentine leukocidin (PVL) and α-hemolysin (Hla), although supporting evidence is lacking. METHODS A rabbit model of necrotizing pneumonia using MRSA clone USA300 was used to compare therapeutic effects of linezolid (50 mg/kg 3 times/day) and vancomycin (30 mg/kg 2 times/day) administered 1.5, 4, and 9 hours after infection on host survival outcomes and in vivo bacterial toxin production. RESULTS Mortality rates were 100% for untreated rabbits and 83%-100% for vancomycin-treated rabbits. In contrast, mortality rates were 25%, 50%, and 100% for rabbits treated with linezolid 1.5, 4, and 9 hours after infection, respectively. Compared with untreated and vancomycin-treated rabbits, improved survival of rabbits treated 1.5 hours after infection with linezolid was associated with a significant decrease in bacterial counts, suppressed bacterial production of PVL and Hla, and reduced production of the neutrophil-chemoattractant interleukin 8 in the lungs. CONCLUSIONS Across the study interval, only early treatment with linezolid resulted in significant suppression of exotoxin synthesis and improved survival outcomes in a rabbit model of MRSA necrotizing pneumonia.
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Affiliation(s)
- Binh An Diep
- Division of Infectious Diseases, Department of Medicine, University of California-San Francisco, 1001 Potrero Ave, San Francisco, CA 94110, USA.
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Oganesyan V, Barnes A, Tkaczyk C, Ferguson A, Wu H, Dall'Acqua WF. Crystallization and preliminary X-ray diffraction analysis of the complex between a human anti-alpha toxin antibody fragment and alpha toxin. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:302-5. [PMID: 23519809 PMCID: PMC3606579 DOI: 10.1107/s1744309113002881] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 01/28/2013] [Indexed: 12/18/2022]
Abstract
Staphylococcus aureus alpha toxin (AT) has been crystallized in complex with the Fab fragment of a human antibody (MEDI4893). This constitutes the first reported crystals of AT bound to an antibody. The monoclinic crystals belonged to space group P2₁, with unit-cell parameters a=85.52, b=148.50, c=93.82 Å, β=99.82°. The diffraction of the crystals extended to 2.56 Å resolution. The asymmetric unit contained two MEDI4893 Fab-AT complexes. This corresponds to a crystal volume per protein weight (VM) of 2.3 Å3 Da(-1) and a solvent content of 47%. The three-dimensional structure of this complex will contribute to an understanding of the molecular basis of the interaction of MEDI4893 with AT. It will also shed light on the mechanism of action of this antibody, the current evaluation of which in the field of S. aureus-mediated diseases makes it a particularly interesting case study. Finally, this study will provide the three-dimensional structure of AT in a monomeric state for the first time.
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Affiliation(s)
- Vaheh Oganesyan
- Department of Antibody Discovery and Protein Engineering, MedImmune, One MedImmune Way, Gaithersburg, MD 20878, USA
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Iwaki S, Spicka J, Tkaczyk C, Jensen BM, Furumoto Y, Charles N, Kovarova M, Rivera J, Horejsi V, Metcalfe DD, Gilfillan AM. Kit- and Fc epsilonRI-induced differential phosphorylation of the transmembrane adaptor molecule NTAL/LAB/LAT2 allows flexibility in its scaffolding function in mast cells. Cell Signal 2007; 20:195-205. [PMID: 17993265 DOI: 10.1016/j.cellsig.2007.10.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Accepted: 10/07/2007] [Indexed: 01/06/2023]
Abstract
The transmembrane adaptor protein (TRAP), NTAL, is phosphorylated in mast cells following FcvarepsilonRI aggregation whereby it cooperates with LAT to induce degranulation. The Kit ligand, stem cell factor (SCF), enhances antigen-induced degranulation and this also appears to be NTAL-dependent. However, Kit and FcvarepsilonRI appear to utilize different mechanisms to induce NTAL phosphorylation. Thus, we examined whether the responsible kinases selectively phosphorylated distinct tyrosines in NTAL and explored the implications for downstream signaling. Whereas FcvarepsilonRI required Lyn and Syk for NTAL phosphorylation, Kit appeared to directly phosphorylate NTAL. Furthermore, co-transfection studies with NTAL constructs revealed that Lyn, Syk, and Kit phosphorylate different tyrosines in NTAL. The tyrosines principally phosphorylated by Syk were recognized as Grb2-binding sites, whereas Lyn and Kit phosphorylated other tyrosines, both inside and outside of these motifs. Pull down studies revealed that PLCgamma1 associated with the two terminal Syk-phosphorylated Grb2-binding sites, which would help to explain the observed decrease in antigen-induced calcium signal and degranulation in NTAL-knock down-human mast cells. The observations reported herein support the conclusion that NTAL may be differentially utilized by specific receptors for relaying alternative signals and this suggests a flexibility in the function of TRAPs not previously appreciated.
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Affiliation(s)
- Shoko Iwaki
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 10 Center Drive, MSC 1881, Bethesda, MD 20892-1881, USA
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Tkaczyk C, Jensen BM, Iwaki S, Gilfillan AM. Adaptive and innate immune reactions regulating mast cell activation: from receptor-mediated signaling to responses. Immunol Allergy Clin North Am 2007; 26:427-50. [PMID: 16931287 DOI: 10.1016/j.iac.2006.05.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In this article, we have described studies that have demonstrated that mast cells can be activated as a consequence of adaptive and innate immune reactions and that these responses can be modified by ligands for other receptors expressed on the surface of mast cells. These various stimuli differentially activate multiple signaling pathways within the mast cells required for the generation and/or release of inflammatory mediators. Thus, the composition of the suite of mediators released and the physiologic ramifications of these responses are dependent on the stimuli and the microenvironment in which the mast cells are activated. Knowledge of the different signaling molecules used by cell surface receptors may allow selective pharmacologic targeting such that inhibiting the adverse effects of mast cell activation can be achieved without influencing the beneficial effects of mast cell activation. The exact interconnections between the signaling pathways initiated by the surface receptors described in this article remain to be completely worked out; thus, this remains a topic for future investigation.
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Affiliation(s)
- Christine Tkaczyk
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Building 10, Room 11C206, 10 Center Drive, MSC 1881, Bethesda, MD 20892, USA
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Abstract
Mast-cell activation mediated by the high-affinity receptor for IgE (FcepsilonRI) is considered to be a key event in the allergic inflammatory response. However, in a physiological setting, other receptors, such as KIT, might also markedly influence the release of mediators by mast cells. Recent studies have provided evidence that FcepsilonRI-dependent degranulation is regulated by two complementary signalling pathways, one of which activates phospholipase Cgamma and the other of which activates phosphatidylinositol 3-kinase, using specific transmembrane and cytosolic adaptor molecules. In this Review, we discuss the evidence for these interacting pathways and describe how the capacity of KIT, and other receptors, to influence FcepsilonRI-dependent mast-cell-mediator release might be a function of the relative abilities of these receptors to activate these alternative pathways.
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Affiliation(s)
- Alasdair M Gilfillan
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Building 10, Room 11C206, 10 Center Drive, MSC 1881, Bethesda, Maryland 20892-1881, USA.
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Abstract
The release of pro-inflammatory mediators from mast cells generally occurs following antigen-dependent aggregation of the high-affinity receptors for IgE (FcepsilonRI) expressed on the cell surface. Under the appropriate conditions, however, other receptors including the high-affinity receptor for IgG (FcgammaRI), Kit, the C3a complement component receptor, and adenosine receptors, can also induce or potentiate mast cell activation. In contrast, receptors such as the FcgammaRIIb low-affinity IgG receptor, and gp49b, when co-ligated with FcepsilonRI, down-regulate mast cell activation. The driving force by which the FcepsilonRI, the FcgammaRI, Kit, and potentially other receptors, lead to mast cell degranulation, arachidonic acid metabolism and cytokine gene expression, is a series of tyrosine kinase-mediated protein phosphorylation events which result in recruitment and subsequent activation of signaling enzymes. Similar processes are required by gp49b and FcgammaRIIb for the down-regulation of mast cell activation. The cellular localization and sequence of these events, the subsequent amplification and diversification of the signaling cascade, and potentially, the termination of these events, are regulated by an important group of signaling proteins termed adaptor molecules. In this chapter, we discuss the structure and properties of these molecules and how these proteins regulate the cellular processes associated with receptor-mediated mast cell activation.
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Affiliation(s)
- Christine Tkaczyk
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Md., USA
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Iwaki S, Tkaczyk C, Satterthwaite AB, Halcomb K, Beaven MA, Metcalfe DD, Gilfillan AM. Btk plays a crucial role in the amplification of Fc epsilonRI-mediated mast cell activation by kit. J Biol Chem 2005; 280:40261-70. [PMID: 16176929 DOI: 10.1074/jbc.m506063200] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Stem cell factor (SCF) acts in synergy with antigen to enhance the calcium signal, degranulation, activation of transcription factors, and cytokine production in human mast cells. However, the underlying mechanisms for this synergy remain unclear. Here we show, utilizing bone marrow-derived mast cells (BMMCs) from Btk and Lyn knock-out mice, that activation of Btk via Lyn plays a key role in promoting synergy. As in human mast cells, SCF enhanced degranulation and cytokine production in BMMCs. In Btk-/- BMMCs, in which there was a partial reduction in the capacity to degranulate in response to antigen, SCF was unable to enhance the residual antigen-mediated degranulation. Furthermore, as with antigen, the ability of SCF to promote cytokine production was abrogated in the Btk-/- BMMCs. The impairment of responses in Btk-/- cells correlated with an inability of SCF to augment phospholipase Cgamma1 activation and calcium mobilization, and to phosphorylate NFkappaB and NFAT for cytokine gene transcription in these cells. Similar studies with Lyn-/- and Btk-/-/Lyn-/- BMMCs indicated that Lyn was a regulator of Btk for these responses. These data demonstrate, for the first time, that Btk is a key regulator of a Kit-mediated amplification pathway that augments Fc epsilonRI-mediated mast cell activation.
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Affiliation(s)
- Shoko Iwaki
- Laboratory of Allergic Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-1881, USA
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Tkaczyk C, Iwaki S, Metcalfe D, Gilfillan A. NTAL and LAT regulation of degranulation and cytokine production by human mast cells (HMCs) after FcεRI and kit mediated activation. J Allergy Clin Immunol 2005. [DOI: 10.1016/j.jaci.2004.12.506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Ali K, Bilancio A, Thomas M, Pearce W, Gilfillan AM, Tkaczyk C, Kuehn N, Gray A, Giddings J, Peskett E, Fox R, Bruce I, Walker C, Sawyer C, Okkenhaug K, Finan P, Vanhaesebroeck B. Essential role for the p110delta phosphoinositide 3-kinase in the allergic response. Nature 2004; 431:1007-11. [PMID: 15496927 DOI: 10.1038/nature02991] [Citation(s) in RCA: 327] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2004] [Accepted: 09/02/2004] [Indexed: 12/20/2022]
Abstract
Inflammatory substances released by mast cells induce and maintain the allergic response. Mast cell differentiation and activation are regulated, respectively, by stem cell factor (SCF; also known as Kit ligand) and by allergen in complex with allergen-specific immunoglobulin E (IgE). Activated SCF receptors and high-affinity receptors for IgE (FcvarepsilonRI) engage phosphoinositide 3-kinases (PI(3)Ks) to generate intracellular lipid second messenger signals. Here, we report that genetic or pharmacological inactivation of the p110delta isoform of PI(3)K in mast cells leads to defective SCF-mediated in vitro proliferation, adhesion and migration, and to impaired allergen-IgE-induced degranulation and cytokine release. Inactivation of p110delta protects mice against anaphylactic allergic responses. These results identify p110delta as a new target for therapeutic intervention in allergy and mast-cell-related pathologies.
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Affiliation(s)
- Khaled Ali
- Ludwig Institute for Cancer Research, 91 Riding House Street, London W1W 7BS, UK
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Hundley TR, Gilfillan AM, Tkaczyk C, Andrade MV, Metcalfe DD, Beaven MA. Kit and FcepsilonRI mediate unique and convergent signals for release of inflammatory mediators from human mast cells. Blood 2004; 104:2410-7. [PMID: 15217825 DOI: 10.1182/blood-2004-02-0631] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In human mast cells, derived from CD34(+) peripheral blood cells, we observed that Kit ligand (KL) failed to induce degranulation but acted in synergy with antigen to markedly enhance degranulation, levels of cytokine gene transcripts, and production of cytokines. Further examination revealed that antigen and KL activated common and unique signaling pathways to account for these varied responses. KL, unlike antigen, failed to activate protein kinase C but activated phospholipase Cgamma and calcium mobilization and augmented these signals as well as degranulation when added together with antigen. Both KL and antigen induced signals that are associated with cytokine production, namely phosphorylation of the mitogen-activated protein kinases, phosphatidylinositol 3-kinase-dependent phosphorylation of protein kinase B (also known as Akt), and phosphorylation of nuclear factor kappaB (NFkappaB). However, only KL stimulated phosphorylation of signal transducer and activator of transcription 5 (STAT5) and STAT6, whereas antigen weakly stimulated the protein kinase C-dependent induction and phosphorylation of c-Jun and associated activating protein-1 (AP-1) components, an action that was markedly potentiated by costimulation with KL. Interestingly, most signals were down-regulated on continuous exposure to KL but were reactivated along with cytokine gene transcription on addition of antigen. The findings, in total, indicated that a combination of FcepsilonRI and Kit-mediated signals and transcriptional processes were required for optimal physiologic responses of human mast cells to antigen.
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Tkaczyk C, Okayama Y, Metcalfe DD, Gilfillan AM. Fcgamma receptors on mast cells: activatory and inhibitory regulation of mediator release. Int Arch Allergy Immunol 2004; 133:305-15. [PMID: 15017113 DOI: 10.1159/000077213] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Mast cell activation and subsequent release of proinflammatory mediators are primarily a consequence of aggregation of the high affinity receptors for IgE (FcepsilonRI) on the mast cell surface following antigen-dependent ligation of FcepsilonRI-bound IgE. However, data obtained from rodent and human mast cells have revealed that IgG receptors (FcgammaR) can both promote and inhibit mast cell activation. These responses appear to be species and/or mast cell phenotype dependent. In CD34+-derived human mast cells exposed to interferon-gamma, FcgammaRI is upregulated, FcgammaRII is expressed but not upregulated, and FcgammaRIII is not expressed. In contrast, in mouse mast cells, FcgammaRII and FcgammaRIII receptors are expressed, whereas FcgammaRI is not. Aggregation of FcgammaRI on human mast cells promotes mediator release in a manner generally similar to that observed following FcepsilonRI aggregation. Aggregation of FcgammaRIIb in mouse mast cells fails to influence cellular processes; however, when coligated with FcepsilonRI, signaling events thus activated downregulate antigen-dependent mediator release. These divergent responses are a consequence of different motifs contained within the cytosolic tails of the signaling subunits of these receptors and the specific signaling molecules recruited by these receptors following ligation. The studies described imply that data obtained in rodent models regarding the influence of FcgammaRs on mast cells may not be directly translatable to the human. The exploitation of FcgammaRs for a potential therapy for the treatment of allergic disorders is discussed in this context.
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Affiliation(s)
- Christine Tkaczyk
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-1881, USA
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Tkaczyk C, Horejsi V, Iwaki S, Draber P, Samelson LE, Satterthwaite AB, Nahm DH, Metcalfe DD, Gilfillan AM. NTAL phosphorylation is a pivotal link between the signaling cascades leading to human mast cell degranulation following Kit activation and Fc epsilon RI aggregation. Blood 2004; 104:207-14. [PMID: 15010370 DOI: 10.1182/blood-2003-08-2769] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aggregation of high-affinity receptors for immunoglobulin E (Fc epsilon RI) on the surface of mast cells results in degranulation, a response that is potentiated by binding of stem cell factor (SCF) to its receptor Kit. We observed that one of the major initial signaling events associated with Fc epsilon RI-mediated activation of human mast cells (HuMCs) is the rapid tyrosine phosphorylation of a protein of 25 to 30 kDa. The phosphorylation of this protein was also observed in response to SCF. This protein was identified as non-T-cell activation linker (NTAL), an adaptor molecule similar to linker for activated T cells (LAT). Unlike the Fc epsilon RI response, SCF induced NTAL phosphorylation in the absence of detectable LAT phosphorylation. When SCF and antigen were added concurrently, there was a marked synergistic effect on NTAL phosphorylation, however, SCF did not enhance the phosphorylation of LAT induced by Fc epsilon RI aggregation. Fc epsilon RI- and SCF-mediated NTAL phosphorylation appear to be differentially regulated by Src kinases and/or Kit kinase, respectively. Diminution of NTAL expression by silencing RNA oligonucleotides in HuMCs resulted in a reduction of both Kit- and Fc epsilon RI-mediated degranulation. NTAL, thus, appears to be an important link between the signaling pathways that are initiated by these receptors, culminating in mast cell degranulation.
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Affiliation(s)
- Christine Tkaczyk
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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