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Gates-Hollingsworth MA, Kolton CB, Hoffmaster AR, Meister GT, Moore AE, Green HR, Pogoda JM, Pillai SP, Kozel TR. Rapid Capsular Antigen Immunoassay for Diagnosis of Inhalational Anthrax: Preclinical Studies and Evaluation in a Nonhuman Primate Model. mBio 2022; 13:e0093122. [PMID: 35546539 PMCID: PMC9239138 DOI: 10.1128/mbio.00931-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 04/15/2022] [Indexed: 11/20/2022] Open
Abstract
Inhalational anthrax is a fatal infectious disease. Rapid and effective treatment is critically dependent on early and accurate diagnosis. Blood culture followed by identification and confirmation may take days to provide clinically relevant information. In contrast, immunoassay for a shed antigen, the capsular polypeptide gamma-d-polyglutamate (γDPGA), can provide rapid results at the point of care. In this study, a lateral flow immunoassay for γDPGA was evaluated in a robust nonhuman primate model of inhalational anthrax. The results showed that the time to a positive result with the rapid test using either serum or blood as a clinical specimen was similar to the time after infection when a blood culture became positive. In vitro testing showed that the test was equally sensitive with cultures of the three major clades of Bacillus anthracis. Cultures from other Bacillus spp. that are known to produce γDPGA also produced positive results. The test was negative with human sera from 200 normal subjects and 45 subjects with culture-confirmed nonanthrax bacterial or fungal sepsis. Taken together, the results showed that immunoassay for γDPGA is an effective surrogate for blood culture in a relevant cynomolgus monkey model of inhalational anthrax. The test would be a valuable aid in early diagnosis of anthrax, which is critical for rapid intervention and a positive outcome. Use of the test could facilitate triage of patients with signs and symptoms of anthrax in a mass-exposure incident and in low-resource settings where laboratory resources are not readily available. IMPORTANCE Patient outcome in anthrax is critically dependent on early diagnosis followed by effective treatment. We describe a rapid lateral flow immunoassay that detects capsular antigen of Bacillus anthracis that is shed into blood during infection. The test was evaluated in a robust cynomolgus monkey model of inhalational anthrax. Rapid detection of capsular antigen is an effective surrogate for the time-consuming and laboratory-intensive diagnosis by blood culture, direct fluorescent antibody staining, or other molecular testing. The test can be performed at the point of patient contact, is rapid and inexpensive, and can be used by individuals with minimal training.
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Affiliation(s)
| | - Cari B. Kolton
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | | | | | - Addie E. Moore
- Battelle Biomedical Research Center, Columbus, Ohio, USA
| | - Heather R. Green
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | | | - Segaran P. Pillai
- Office of the Commissioner, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Thomas R. Kozel
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
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2
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O’Brien C, Varty K, Ignaszak A. The electrochemical detection of bioterrorism agents: a review of the detection, diagnostics, and implementation of sensors in biosafety programs for Class A bioweapons. MICROSYSTEMS & NANOENGINEERING 2021; 7:16. [PMID: 33585038 PMCID: PMC7872827 DOI: 10.1038/s41378-021-00242-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 01/03/2021] [Indexed: 05/10/2023]
Abstract
During the past year, disease has shown us the iron grip it can hold over a population of people. Health systems can be overwhelmed, economies can be brought into recession, and many people can be harmed or killed. When weaponized, diseases can be manipulated to create a detriment to health while becoming an economic burden on any society. It is consequently prudent that easy detection of bioweapons is available to governments for protecting their people. Electrochemical sensing displays many distinct advantages, such as its low limit of detection, low cost to run, rapid generation of results, and in many instances portability. We therefore present a wide array of electrochemical sensing platforms currently being fabricated, a brief summary of Class A bioweapons, and the potential future of bioweapon detection and biosafety.
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Affiliation(s)
- Connor O’Brien
- Department of Chemistry, University of New Brunswick, 30 Dineen Drive, Fredericton, NB E3B 5A3 Canada
| | - Kathleen Varty
- Department of Chemistry, University of New Brunswick, 30 Dineen Drive, Fredericton, NB E3B 5A3 Canada
| | - Anna Ignaszak
- Department of Chemistry, University of New Brunswick, 30 Dineen Drive, Fredericton, NB E3B 5A3 Canada
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Tournier JN, Rougeaux C. Anthrax Toxin Detection: From In Vivo Studies to Diagnostic Applications. Microorganisms 2020; 8:microorganisms8081103. [PMID: 32717946 PMCID: PMC7464488 DOI: 10.3390/microorganisms8081103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/19/2020] [Accepted: 07/21/2020] [Indexed: 11/16/2022] Open
Abstract
Anthrax toxins are produced by Bacillus anthracis throughout infection and shape the physiopathogenesis of the disease. They are produced in low quantities but are highly efficient. They have thus been long ignored, but recent biochemical methods have improved our knowledge in animal models. This article reviews the various methods that have been used and how they could be applied to clinical diagnosis.
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Affiliation(s)
- Jean-Nicolas Tournier
- Unité Bactériologie Biothérapies Anti-infectieuses et Immunité, Institut de Recherche Biomédicale des Armées (IRBA), 1 place Général Valérie André, 91220 Brétigny sur Orge, France;
- Centre National de Référence-Laboratoire Expert Charbon, 1 place Général Valérie André, 91220 Brétigny sur Orge, France
- Innovative Vaccine Laboratory, Institut Pasteur, 28 rue du docteur Roux, 75015 Paris, France
- Ecole du Val-de-Grâce, 1 place Alphonse Laveran, 75005 Paris, France
| | - Clémence Rougeaux
- Unité Bactériologie Biothérapies Anti-infectieuses et Immunité, Institut de Recherche Biomédicale des Armées (IRBA), 1 place Général Valérie André, 91220 Brétigny sur Orge, France;
- Centre National de Référence-Laboratoire Expert Charbon, 1 place Général Valérie André, 91220 Brétigny sur Orge, France
- Correspondence: ; Tel.: +33-178-651-891
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Solano MI, Woolfitt AR, Boyer AE, Lins RC, Isbell K, Gallegos-Candela M, Moura H, Pierce CL, Barr JR. Accurate and selective quantification of anthrax protective antigen in plasma by immunocapture and isotope dilution mass spectrometry. Analyst 2019; 144:2264-2274. [PMID: 30810119 PMCID: PMC7015108 DOI: 10.1039/c8an02479k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Anthrax protective antigen (83 kDa, PA83) is an essential component of two major binary toxins produced by Bacillus anthracis, lethal toxin (LTx) and edema toxin (ETx). During infection, LTx and ETx contribute to immune collapse, endothelial dysfunction, hemorrhage and high mortality. Following protease cleavage on cell receptors or in circulation, the 20 kDa (PA20) N-terminus is released, activating the 63 kDa (PA63) form which binds lethal factor (LF) and edema factor (EF), facilitating their entry into their cellular targets. Several ELISA-based PA methods previously developed are primarily qualitative or semi-quantitative. Here, we combined protein immunocapture, tryptic digestion and isotope dilution liquid chromatography-mass spectrometry (LC-MS/MS), to develop a highly selective and sensitive method for detection and accurate quantification of total-PA (PA83 + PA63) and PA83. Two tryptic peptides in the 63 kDa region measure total-PA and three in the 20 kDa region measure PA83 alone. Detection limits range from 1.3-2.9 ng mL-1 PA in 100 μL of plasma. Spiked recovery experiments with combinations of PA83, PA63, LF and EF in plasma showed that PA63 and PA83 were quantified accurately against the PA83 standard and that LF and EF did not interfere with accuracy. Applied to a study of inhalation anthrax in rhesus macaques, total-PA suggested triphasic kinetics, similar to that previously observed for LF and EF. This study is the first to report circulating PA83 in inhalation anthrax, typically at less than 4% of the levels of PA63, providing the first evidence that activated PA63 is the primary form of PA throughout infection.
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Affiliation(s)
- Maria I Solano
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway, Atlanta, GA 30341, USA.
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Mao Q, Liu X, Chen C, Ye J, Liang H, Li B, Sun X, Sun L, Sun Y, Mu X, Li L. A dual-label time-resolved fluorescence immunoassay for the simultaneous determination of carcinoembryonic antigen and squamous cell carcinoma antigen. Biotechnol Appl Biochem 2018; 65:816-821. [PMID: 29679420 DOI: 10.1002/bab.1663] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 04/14/2018] [Indexed: 01/15/2023]
Abstract
Among women worldwide, cervical cancer is the second-most common cancer, and cervical smears and DNA detection have low sensitivity or are too expensive. The concentrations of carcinoembryonic antigen (CEA) and squamous cell carcinoma (SCC) in the serum were detected using a sandwich immunoassay. The CEA and SCC in the serum were captured by anti-CEA and anti-SCC antibodies. After combining other anti-CEA- and anti-SCC-labeled antibodies with europium (III) (Eu3+ ) and samarium (III) (Sm3+ ) chelates, CEA and SCC were detected with time-resolved fluorometry (TRF). The linear correlation coefficients (R2 ) of the CEA and SCC standard curves were 0.9997 and 0.9997, respectively. The minimum detection level for CEA was 1.15 ng/mL (the linear dynamic range was 3.24-543.67 ng/mL), and the average recovery was 100.83%. The sensitivity for SCC detection was 0.54 ng/mL (the linear dynamic range was 2.47-96.58 ng/mL), and the average recovery was 101.02%. High R2 between the results of commercial assays and this method were obtained (R2 = 0.9983 for CEA, R2 = 0.9878 for SCC). These findings indicated that the dual-label TRFIA invented in this study has high sensitivity, accuracy, and specificity in clinical analysis, which indicates that this method could be used for the early diagnosis and follow-up surveillance of cervical cancer.
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Affiliation(s)
- Qian Mao
- Endocrinology Department, Hospital of Beihua University, Jilin, People's Republic of China
| | - Xiaohong Liu
- Endocrinology Department, Hospital of Beihua University, Jilin, People's Republic of China
| | - CuiCui Chen
- Guangzhou Youdi Bio-technology Co., Ltd., Guangzhou, People's Republic of China
| | - Jingwen Ye
- Guangzhou Youdi Bio-technology Co., Ltd., Guangzhou, People's Republic of China
| | - Huankun Liang
- Guangzhou Youdi Bio-technology Co., Ltd., Guangzhou, People's Republic of China
| | - Binxian Li
- Endocrinology Department, Hospital of Beihua University, Jilin, People's Republic of China
| | - Xinyi Sun
- Endocrinology Department, Hospital of Beihua University, Jilin, People's Republic of China
| | - Lin Sun
- Endocrinology Department, Hospital of Beihua University, Jilin, People's Republic of China
| | - Yuman Sun
- Endocrinology Department, Hospital of Beihua University, Jilin, People's Republic of China
| | - Xiaomei Mu
- Endocrinology Department, Hospital of Beihua University, Jilin, People's Republic of China
| | - Laiqing Li
- Guangzhou Youdi Bio-technology Co., Ltd., Guangzhou, People's Republic of China
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Gallegos-Candela M, Boyer AE, Woolfitt AR, Brumlow J, Lins RC, Quinn CP, Hoffmaster AR, Meister G, Barr JR. Validated MALDI-TOF-MS method for anthrax lethal factor provides early diagnosis and evaluation of therapeutics. Anal Biochem 2017; 543:97-107. [PMID: 29224733 PMCID: PMC7904043 DOI: 10.1016/j.ab.2017.12.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 12/01/2017] [Accepted: 12/06/2017] [Indexed: 01/12/2023]
Abstract
Anthrax lethal factor (LF) is a zinc-dependent endoprotease and a critical virulence factor for Bacillus anthracis, the causative agent of anthrax. The mass spectrometry (MS) method for total-LF quantification includes three steps; 1) LF specific antibody capture/concentration, 2) LF-specific hydrolysis of a peptide substrate, and 3) detection and quantification of LF-cleaved peptides by isotope-dilution MALDI-TOF/MS. Recombinant LF spiked plasma was used for calibration and quality control (QC) materials. Specificity was 100% from analysis of serum and plasma from 383 non-infected humans, 31 rabbits, and 24 rhesus macaques. Sensitivity was 100% from 32 human clinical anthrax cases including infections by inhalation, ingestion, cutaneous and injection exposures and experimental infections for 29 rabbits and 24 rhesus macaques with inhalation anthrax. Robustness evaluation included sample storage, serum and plasma, antimicrobial and antitoxin effects and long-term performance. Data from 100 independent runs gave detection limits 0.01 ng/mL (111 amol/mL) for the 4-h method and 0.0027 ng/mL (30 amol/mL) for an alternate 20-h method. QC precision ranged from 7.7 to 14.8% coefficient of variation and accuracy from 0.2 to 9.8% error. The validated LF MS method provides sensitive quantification of anthrax total-LF using a robust high throughput platform for early diagnosis and evaluation of therapeutics during an anthrax emergency.
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Affiliation(s)
- Maribel Gallegos-Candela
- Centers for Disease Control and Prevention, 4770 Buford Highway Mailstop F-50, Atlanta, GA 30341, USA
| | - Anne E Boyer
- Centers for Disease Control and Prevention, 4770 Buford Highway Mailstop F-50, Atlanta, GA 30341, USA.
| | - Adrian R Woolfitt
- Centers for Disease Control and Prevention, 4770 Buford Highway Mailstop F-50, Atlanta, GA 30341, USA
| | - Judy Brumlow
- Battelle Atlanta Analytical Services, 2987 Clairmont Road NE, Suite 450, Atlanta, GA 30329, USA
| | - Renato C Lins
- Battelle Atlanta Analytical Services, 2987 Clairmont Road NE, Suite 450, Atlanta, GA 30329, USA
| | - Conrad P Quinn
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30329, USA
| | - Alex R Hoffmaster
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30329, USA
| | - Gabriel Meister
- Battelle Biomedical Research Center, 1425 Plain City Georgesville Rd, West Jefferson, OH 43162, USA
| | - John R Barr
- Centers for Disease Control and Prevention, 4770 Buford Highway Mailstop F-50, Atlanta, GA 30341, USA
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7
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Anthrax immune globulin improves hemodynamics and survival during B. anthracis toxin-induced shock in canines receiving titrated fluid and vasopressor support. Intensive Care Med Exp 2017; 5:48. [PMID: 29058092 PMCID: PMC5651533 DOI: 10.1186/s40635-017-0159-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 09/22/2017] [Indexed: 11/10/2022] Open
Abstract
Background Although anthrax immune globulin (AIG) improved survival in antibiotic-treated Bacillus anthracis-challenged animal models, whether it adds to the benefit of conventional hemodynamic support for B. anthracis toxin-associated shock is unknown. Methods We therefore tested AIG in sedated, mechanically ventilated canines challenged with 24-h B. anthracis lethal and edema toxin infusions and supported for 96 h with a previously demonstrated protective regimen of titrated normal saline and norepinephrine. Results Compared to controls, proportional survival (%) was increased with AIG treatment started 4 h before (33 vs. 100%, n = 6 each) or 2 h (17 vs. 86%, n = 6 and 7 respectively) or 5 h (0 vs. 67%, n = 3 each) after the start of toxin (p ≤ 0.05) and overall [3 survivors of 15 controls (20%) vs. 14 of 16 AIG animals (88%); p = 0.006]. Averaged across treatment times, AIG increased blood pressure at 48 h and decreased norepinephrine requirements at 72 h (p ≤ 0.02), increased left ventricular ejection fraction at 48 and 72 h (p ≤ 0.02), and increased urine output and decreased net fluid balance at 72 and 96 h (p ≤ 0.04). AIG also reduced acidosis and renal and hepatic injury markers between 24 and 96 h. Conclusions These findings further support AIG’s potential benefit for patients with B. anthracis infection and developing toxin-associated shock. Electronic supplementary material The online version of this article (10.1186/s40635-017-0159-9) contains supplementary material, which is available to authorized users.
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8
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Goldstein JM, Lee J, Tang X, Boyer AE, Barr JR, Bagarozzi DA, Quinn CP. Phage Display Analysis of Monoclonal Antibody Binding to Anthrax Toxin Lethal Factor. Toxins (Basel) 2017. [PMCID: PMC5535168 DOI: 10.3390/toxins9070221] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
AVR1674 and AVR1675 are monoclonal antibodies (mAbs) that bind with high specificity to anthrax toxin lethal factor (LF) and lethal toxin (LTx). These mAbs have been used as pivotal reagents to develop anthrax toxin detection tests using mass spectrometry. The mAbs were demonstrated to bind LF with good affinity (KD 10−7–10−9 M) and to enhance LF-mediated cleavage of synthetic peptide substrates in vitro. Sequence analysis indicated that the mAbs shared 100% amino acid identity in their complementarity determining regions (CDR). A phage display library based on a combinatorial library of random heptapeptides fused to the pIII coat protein of M13 phage was enriched and screened to identify peptide sequences with mAb binding properties. Selection and sequence analysis of 18 anti-LF-reactive phage clones identified a 7-residue (P1–P7) AVR1674/1675 consensus target binding sequence of TP1-XP2-K/RP3-DP4-D/EP5-ZP6-X/ZP7 (X = aromatic, Z = non-polar). The phage peptide sequence with highest affinity binding to AVR1674/1675 was identified as T-F-K-D-E-I-V. Synthetic oligopeptides were designed based on the phage sequences and interacted with mAbs with high affinity (KD ~ 10−9 M). Single amino acid substitutions of A, H, or Q in the peptides identified positions P1–P5 as critical residues for mAb-peptide interactions. CLUSTALW alignment of phage sequences with native LF implicated residues 644–650 (sequence T-H-Q-D-E-I-Y) as a putative linear epitope component located within a structural loop (L2) of LF Domain IV. The activation effects of these mAbs contribute to the analytic sensitivity of function-based LF detection assays.
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Affiliation(s)
- Jason M. Goldstein
- Reagent and Diagnostic Services Branch, Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, MS-A03, 1600 Clifton Road, Atlanta, GA 30333, USA; (J.L.); (X.T.); (D.A.B.J.)
- Correspondence: ; Tel.: +1-404-639-2258
| | - Joo Lee
- Reagent and Diagnostic Services Branch, Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, MS-A03, 1600 Clifton Road, Atlanta, GA 30333, USA; (J.L.); (X.T.); (D.A.B.J.)
| | - Xiaoling Tang
- Reagent and Diagnostic Services Branch, Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, MS-A03, 1600 Clifton Road, Atlanta, GA 30333, USA; (J.L.); (X.T.); (D.A.B.J.)
| | - Anne E. Boyer
- Clinical Chemistry Branch, Division of Laboratory Services, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy, NE, Atlanta, GA 30341, USA; (A.E.B.); (J.R.B.)
| | - John R. Barr
- Clinical Chemistry Branch, Division of Laboratory Services, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy, NE, Atlanta, GA 30341, USA; (A.E.B.); (J.R.B.)
| | - Dennis A. Bagarozzi
- Reagent and Diagnostic Services Branch, Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, MS-A03, 1600 Clifton Road, Atlanta, GA 30333, USA; (J.L.); (X.T.); (D.A.B.J.)
| | - Conrad P. Quinn
- Meningitis and Vaccine Preventable Diseases Branch, Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, MS-D17, 1600 Clifton Road, Atlanta, GA 30333, USA;
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In vivo dynamics of active edema and lethal factors during anthrax. Sci Rep 2016; 6:23346. [PMID: 26996161 PMCID: PMC4800402 DOI: 10.1038/srep23346] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 02/26/2016] [Indexed: 01/21/2023] Open
Abstract
Lethal and edema toxins are critical virulence factors of Bacillus anthracis. However, little is known about their in vivo dynamics of production during anthrax. In this study, we unraveled for the first time the in vivo kinetics of production of the toxin components EF (edema factor) and LF (lethal factor) during cutaneous infection with a wild-type toxinogenic encapsulated strain in immuno-competent mice. We stratified the asynchronous infection process into defined stages through bioluminescence imaging (BLI), while exploiting sensitive quantitative methods by measuring the enzymatic activity of LF and EF. LF was produced in high amounts, while EF amounts steadily increased during the infectious process. This led to high LF/EF ratios throughout the infection, with variations between 50 to a few thousands. In the bloodstream, the early detection of active LF and EF despite the absence of bacteria suggests that they may exert long distance effects. Infection with a strain deficient in the protective antigen toxin component enabled to address its role in the diffusion of LF and EF within the host. Our data provide a picture of the in vivo complexity of the infectious process.
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Quantitative Determination of Lethal Toxin Proteins in Culture Supernatant of Human Live Anthrax Vaccine Bacillus anthracis A16R. Toxins (Basel) 2016; 8:toxins8030056. [PMID: 26927174 PMCID: PMC4810201 DOI: 10.3390/toxins8030056] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 02/04/2016] [Accepted: 02/05/2016] [Indexed: 12/26/2022] Open
Abstract
Bacillus anthracis (B. anthracis) is the etiological agent of anthrax affecting both humans and animals. Anthrax toxin (AT) plays a major role in pathogenesis. It includes lethal toxin (LT) and edema toxin (ET), which are formed by the combination of protective antigen (PA) and lethal factor (LF) or edema factor (EF), respectively. The currently used human anthrax vaccine in China utilizes live-attenuated B. anthracis spores (A16R; pXO1+, pXO2−) that produce anthrax toxin but cannot produce the capsule. Anthrax toxins, especially LT, have key effects on both the immunogenicity and toxicity of human anthrax vaccines. Thus, determining quantities and biological activities of LT proteins expressed by the A16R strain is meaningful. Here, we explored LT expression patterns of the A16R strain in culture conditions using another vaccine strain Sterne as a control. We developed a sandwich ELISA and cytotoxicity-based method for quantitative detection of PA and LF. Expression and degradation of LT proteins were observed in culture supernatants over time. Additionally, LT proteins expressed by the A16R and Sterne strains were found to be monomeric and showed cytotoxic activity, which may be the main reason for side effects of live anthrax vaccines. Our work facilitates the characterization of anthrax vaccines components and establishment of a quality control standard for vaccine production which may ultimately help to ensure the efficacy and safety of the human anthrax vaccine A16R.
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Das R, Goel AK, Sharma MK, Upadhyay S. Electrochemical DNA sensor for anthrax toxin activator gene atxA-detection of PCR amplicons. Biosens Bioelectron 2015; 74:939-46. [DOI: 10.1016/j.bios.2015.07.066] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 07/15/2015] [Accepted: 07/28/2015] [Indexed: 02/08/2023]
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Ascough S, Altmann DM. Anthrax in injecting drug users: the need for increased vigilance in the clinic. Expert Rev Anti Infect Ther 2015; 13:681-4. [DOI: 10.1586/14787210.2015.1032255] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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13
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High-sensitivity MALDI-TOF MS quantification of anthrax lethal toxin for diagnostics and evaluation of medical countermeasures. Anal Bioanal Chem 2015; 407:2847-58. [PMID: 25673244 PMCID: PMC4369318 DOI: 10.1007/s00216-015-8509-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 01/13/2015] [Accepted: 01/21/2015] [Indexed: 11/15/2022]
Abstract
Inhalation anthrax has a rapid progression and high fatality rate. Pathology and death from inhalation of Bacillus anthracis spores are attributed to the actions of secreted protein toxins. Protective antigen (PA) binds and imports the catalytic component lethal factor (LF), a zinc endoprotease, and edema factor (EF), an adenylyl cyclase, into susceptible cells. PA-LF is termed lethal toxin (LTx) and PA-EF, edema toxin. As the universal transporter for both toxins, PA is an important target for vaccination and immunotherapeutic intervention. However, its quantification has been limited to methods of relatively low analytic sensitivity. Quantification of LTx may be more clinically relevant than LF or PA alone because LTx is the toxic form that acts on cells. A method was developed for LTx-specific quantification in plasma using anti-PA IgG magnetic immunoprecipitation of PA and quantification of LF activity that co-purified with PA. The method was fast (<4 h total time to detection), sensitive at 0.033 ng/mL LTx in plasma for the fast analysis (0.0075 ng/mL LTx in plasma for an 18 h reaction), precise (6.3–9.9 % coefficient of variation), and accurate (0.1–12.7 %error; n ≥ 25). Diagnostic sensitivity was 100 % (n = 27 animal/clinical cases). Diagnostic specificity was 100 % (n = 141). LTx was detected post-antibiotic treatment in 6/6 treated rhesus macaques and 3/3 clinical cases of inhalation anthrax and as long as 8 days post-treatment. Over the course of infection in two rhesus macaques, LTx was first detected at 0.101 and 0.237 ng/mL at 36 h post-exposure and increased to 1147 and 12,107 ng/mL in late-stage anthrax. This demonstrated the importance of LTx as a diagnostic and therapeutic target. This method provides a sensitive, accurate tool for anthrax toxin detection and evaluation of PA-directed therapeutics. Method schematic for analysis of anthrax lethal toxin activity by ID-MALDI-TOF MS ![]()
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