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Toxin-neutralizing antibodies elicited by naturally acquired cutaneous anthrax are elevated following severe disease and appear to target conformational epitopes. PLoS One 2020; 15:e0230782. [PMID: 32294093 PMCID: PMC7159215 DOI: 10.1371/journal.pone.0230782] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 03/09/2020] [Indexed: 01/03/2023] Open
Abstract
Understanding immune responses to native antigens in response to natural infections can lead to improved approaches to vaccination. This study sought to characterize the humoral immune response to anthrax toxin components, capsule and spore antigens in individuals (n = 46) from the Kayseri and Malatya regions of Turkey who had recovered from mild or severe forms of cutaneous anthrax infection, compared to regional healthy controls (n = 20). IgG antibodies to each toxin component, the poly-γ-D-glutamic acid capsule, the Bacillus collagen-like protein of anthracis (BclA) spore antigen, and the spore carbohydrate anthrose, were detected in the cases, with anthrax toxin neutralization and responses to Protective Antigen (PA) and Lethal Factor (LF) being higher following severe forms of the disease. Significant correlative relationships among responses to PA, LF, Edema Factor (EF) and capsule were observed among the cases. Though some regional control sera exhibited binding to a subset of the tested antigens, these samples did not neutralize anthrax toxins and lacked correlative relationships among antigen binding specificities observed in the cases. Comparison of serum binding to overlapping decapeptides covering the entire length of PA, LF and EF proteins in 26 cases compared to 8 regional controls revealed that anthrax toxin-neutralizing antibody responses elicited following natural cutaneous anthrax infection are directed to conformational epitopes. These studies support the concept of vaccination approaches that preserve conformational epitopes.
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Davis CW, Jackson KJL, McElroy AK, Halfmann P, Huang J, Chennareddy C, Piper AE, Leung Y, Albariño CG, Crozier I, Ellebedy AH, Sidney J, Sette A, Yu T, Nielsen SCA, Goff AJ, Spiropoulou CF, Saphire EO, Cavet G, Kawaoka Y, Mehta AK, Glass PJ, Boyd SD, Ahmed R. Longitudinal Analysis of the Human B Cell Response to Ebola Virus Infection. Cell 2019; 177:1566-1582.e17. [PMID: 31104840 PMCID: PMC6908968 DOI: 10.1016/j.cell.2019.04.036] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 02/11/2019] [Accepted: 04/16/2019] [Indexed: 01/12/2023]
Abstract
Ebola virus (EBOV) remains a public health threat. We performed a longitudinal study of B cell responses to EBOV in four survivors of the 2014 West African outbreak. Infection induced lasting EBOV-specific immunoglobulin G (IgG) antibodies, but their subclass composition changed over time, with IgG1 persisting, IgG3 rapidly declining, and IgG4 appearing late. Striking changes occurred in the immunoglobulin repertoire, with massive recruitment of naive B cells that subsequently underwent hypermutation. We characterized a large panel of EBOV glycoprotein-specific monoclonal antibodies (mAbs). Only a small subset of mAbs that bound glycoprotein by ELISA recognized cell-surface glycoprotein. However, this subset contained all neutralizing mAbs. Several mAbs protected against EBOV disease in animals, including one mAb that targeted an epitope under evolutionary selection during the 2014 outbreak. Convergent antibody evolution was seen across multiple donors, particularly among VH3-13 neutralizing antibodies specific for the GP1 core. Our study provides a benchmark for assessing EBOV vaccine-induced immunity. Ebola virus infection causes massive recruitment of naive B cells Virus-specific antibodies continue to class-switch and mutate for months after acute infection Protective antibodies can be neutralizing or non-neutralizing and can appear early Convergent, protective antibody rearrangements are seen in multiple donors
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Affiliation(s)
- Carl W Davis
- Emory Vaccine Center and Department of Microbiology and Immunology, Emory University, Atlanta, GA, USA
| | - Katherine J L Jackson
- Department of Pathology, Stanford University, Stanford, CA, USA; Immunology Division, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
| | - Anita K McElroy
- Viral Special Pathogens Branch, US Centers for Disease Control and Prevention, Atlanta, GA, USA; Division of Pediatric Infectious Disease, Emory University, Atlanta, GA, USA; Division of Pediatric Infectious Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Peter Halfmann
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, WI, USA
| | - Jessica Huang
- Emory Vaccine Center and Department of Microbiology and Immunology, Emory University, Atlanta, GA, USA
| | - Chakravarthy Chennareddy
- Emory Vaccine Center and Department of Microbiology and Immunology, Emory University, Atlanta, GA, USA
| | - Ashley E Piper
- Virology Division, United States Army Medical Research Institute for Infectious Diseases, Fort Detrick, MD, USA
| | | | - César G Albariño
- Viral Special Pathogens Branch, US Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Ian Crozier
- Integrated Research Facility at Fort Detrick, Clinical Monitoring Research Program Directorate, Frederick National Laboratory for Cancer Research sponsored by the National Cancer Institutes, Frederick, MD, USA
| | - Ali H Ellebedy
- Emory Vaccine Center and Department of Microbiology and Immunology, Emory University, Atlanta, GA, USA; Division of Immunobiology, Department of Pathology and Immunology Washington University School of Medicine, St. Louis, MO, USA
| | - John Sidney
- Division of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA
| | - Alessandro Sette
- Division of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA; Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Tianwei Yu
- Department of Biostatistics and Bioinformatics, Emory University, Atlanta, GA, USA
| | | | - Arthur J Goff
- Virology Division, United States Army Medical Research Institute for Infectious Diseases, Fort Detrick, MD, USA
| | - Christina F Spiropoulou
- Viral Special Pathogens Branch, US Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Erica Ollman Saphire
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, USA; La Jolla Institute for Immunology, La Jolla, CA, USA
| | | | - Yoshihiro Kawaoka
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, WI, USA; Division of Virology, Department of Microbiology and Immunology, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Aneesh K Mehta
- Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, GA, USA
| | - Pamela J Glass
- Virology Division, United States Army Medical Research Institute for Infectious Diseases, Fort Detrick, MD, USA
| | - Scott D Boyd
- Department of Pathology, Stanford University, Stanford, CA, USA
| | - Rafi Ahmed
- Emory Vaccine Center and Department of Microbiology and Immunology, Emory University, Atlanta, GA, USA.
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Humoral and Cell-Mediated Immune Responses to Alternate Booster Schedules of Anthrax Vaccine Adsorbed in Humans. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2016; 23:326-38. [PMID: 26865594 DOI: 10.1128/cvi.00696-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/02/2016] [Indexed: 12/28/2022]
Abstract
Protective antigen (PA)-specific antibody and cell-mediated immune (CMI) responses to annual and alternate booster schedules of anthrax vaccine adsorbed (AVA; BioThrax) were characterized in humans over 43 months. Study participants received 1 of 6 vaccination schedules: a 3-dose intramuscular (IM) priming series (0, 1, and 6 months) with a single booster at 42 months (4-IM); 3-dose IM priming with boosters at 18 and 42 months (5-IM); 3-dose IM priming with boosters at 12, 18, 30, and 42 months (7-IM); the 1970 licensed priming series of 6 doses (0, 0.5, 1, 6, 12, and 18 months) and two annual boosters (30 and 42 months) administered either subcutaneously (SQ) (8-SQ) or IM (8-IM); or saline placebo control at all eight time points. Antibody response profiles included serum anti-PA IgG levels, subclass distributions, avidity, and lethal toxin neutralization activity (TNA). CMI profiles included frequencies of gamma interferon (IFN-γ)- and interleukin 4 (IL-4)-secreting cells and memory B cells (MBCs), lymphocyte stimulation indices (SI), and induction of IFN-γ, IL-2, IL-4, IL-6, IL-1β, and tumor necrosis factor alpha (TNF-α) mRNA. All active schedules elicited high-avidity PA-specific IgG, TNA, MBCs, and T cell responses with a mixed Th1-Th2 profile and Th2 dominance. Anti-PA IgG and TNA were highly correlated (e.g., month 7,r(2)= 0.86,P< 0.0001, log10 transformed) and declined in the absence of boosters. Boosters administered IM generated the highest antibody responses. Increasing time intervals between boosters generated antibody responses that were faster than and superior to those obtained with the final month 42 vaccination. CMI responses to the 3-dose IM priming remained elevated up to 43 months. (This study has been registered at ClinicalTrials.gov under registration no. NCT00119067.).
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A heterologous helper T-cell epitope enhances the immunogenicity of a multiple-antigenic-peptide vaccine targeting the cryptic loop-neutralizing determinant of Bacillus anthracis protective antigen. Infect Immun 2009; 77:5509-18. [PMID: 19805525 DOI: 10.1128/iai.00899-09] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously showed that a multiple antigenic peptide (MAP) displaying amino acids (aa) 305 to 319 from the 2beta2-2beta3 loop of protective antigen (PA) can elicit high-titered antibody that neutralizes lethal toxin (LeTx) in vitro and that this loop-neutralizing determinant (LND) specificity is absent in PA-immune rabbits. Some immune rabbits were, however, nonresponders to the MAP. We hypothesized that the immunogen elicited suboptimal major histocompatibility complex (MHC) class II-restricted T-cell help and that introduction of a functional helper T-cell epitope would increase MHC-restricted responsiveness and the magnitude and affinity of the antibody responses. In the current study, we characterized the T- and B-cell responses to LND peptides in mice, then designed second-generation MAP immunogens for eliciting LND-specific immunity, and tested them in rabbits. The 305-319 sequence was devoid of helper T-cell epitopes in three strains of mice; however, a T-B peptide comprising aa 305 to 319, colinearly synthesized with the P30 helper epitope of tetanus toxin, elicited robust LeTx-neutralizing immunity in mice. T-B MAPs displaying B-cell epitopes 304 to 319 (MAP304) or 305 to 319 (MAP305) elicited high-titer, durable antibody responses in rabbits which exhibited potent neutralization of LeTx in vitro. All MAP304-immune rabbits demonstrated neutralization titers exceeding that of hyperimmune sera of rabbits immunized with PA in Freund's adjuvant, with peak neutralization titers 23-, 6-, and 3-fold higher than that of the PA antiserum. Overall, immunization with MAPs containing the P30 epitope elicited higher antibody and toxin neutralization titers and peptide-specific affinity than immunization with an LND MAP lacking a helper epitope. P30-containing MAP304 represents a promising LND-specific vaccine for anthrax.
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Galen JE, Chinchilla M, Pasetti MF, Wang JY, Zhao L, Arciniega-Martinez I, Silverman DJ, Levine MM. Mucosal immunization with attenuated Salmonella enterica serovar Typhi expressing protective antigen of anthrax toxin (PA83) primes monkeys for accelerated serum antibody responses to parenteral PA83 vaccine. J Infect Dis 2009; 199:326-35. [PMID: 19099487 DOI: 10.1086/596066] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Salmonella enterica serovar Typhi vaccine strain CVD 908-htrA was genetically engineered for stable plasmid-based expression of protective antigen of anthrax toxin (PA83) fused with the export protein ClyA (ClyA-PA83). The priming potential of CVD 908-htrA expressing ClyA-PA83 was assessed in 12 rhesus and 20 cynomolgus macaques that were immunized mucosally (i.e., intranasally) on days 0 and 14. A parenteral booster with purified PA83 plus alum was given to rhesus macaques on days 42 and 225; cynomolgus monkeys received a booster with either PA or licensed anthrax vaccine (BioThrax; Emergent Biosolutions) only one time, 3 months after priming. Monkeys primed with S. Typhi expressing ClyA-PA83 developed high levels of serum toxin-neutralization activity (TNA) antibodies (50% effective dose [ED50], >1.3x10(3)), 7 days after receipt of the booster, whereas unprimed controls lacked serum TNA (ED50, 0). In nonhuman primates, the success of this anthrax vaccine strategy based on heterologous mucosal priming followed by a parenteral subunit vaccine booster paves the way for clinical trials.
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Affiliation(s)
- James E Galen
- Center for Vaccine Development, Division of Geographic Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Li H, Soroka SD, Taylor TH, Stamey KL, Stinson KW, Freeman AE, Abramson DR, Desai R, Cronin LX, Oxford JW, Caba J, Pleatman C, Pathak S, Schmidt DS, Semenova VA, Martin SK, Wilkins PP, Quinn CP. Standardized, mathematical model-based and validated in vitro analysis of anthrax lethal toxin neutralization. J Immunol Methods 2008; 333:89-106. [PMID: 18304568 DOI: 10.1016/j.jim.2008.01.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 01/11/2008] [Accepted: 01/17/2008] [Indexed: 01/15/2023]
Abstract
Quantification of anthrax lethal toxin (LTx) neutralization activity (TNA) is pivotal in assessing protective antibody responses to anthrax vaccines and for evaluation of immunotherapies for anthrax. We have adapted and redesigned the TNA assay to establish a unifying, standardized, quantitative and validated technology platform for LTx neutralization in the J774A.1 murine cell line. Critical design features of this platform are 1) the application of a free-form or constrained 4 parameter logistic (4-PL) function to model neutralization responses within and between boundary limits of 100% cell survival and 95% cell lysis and 2) to exploit innovative assay curve recognition algorithms for interpretive endpoints. The assay was validated using human serum ED50 (dilution of serum effecting 50% neutralization) as the primary reportable value (RV). Intra-operator and intermediate precision, expressed as the coefficient of variation (%CV), were high at 10.5-15.5%CV and 13.5-14.5%CV respectively. TNA assay dilutional linearity was demonstrated for human sera using linear regression analysis of log(10) transformed data with slope=0.99, intercept=-0.03 and r(2)=0.985. Assay accuracy, inferred from the precision and linearity data and using a spike-recovery approach, was high with a percent error (%E) range of only 3.4-20.5%E. The lower limit of detection (LLOD) was ED50=12 and the lower limit of quantification (LLOQ) was ED50=36. The cell-based assay was robust, tolerating incubation temperatures from 35 to 39 degrees C, CO(2) concentrations from 3% to 7% and reporter substrate (MTT) concentrations of 2.5-7.5 mg/ml. Strict assay quality control parameters were met for up to 25 cell culture passages. The long term (50 month) assay stability, determined using human reference standards AVR414 and AVR801, indicated high precision, consistent accuracy and no detectable assay drift. A customized software program provided two additional assay metrics, Quantification Titer (QT) and Threshold Titer (TT), both of which demonstrate acceptable accuracy, precision and dilutional linearity. The TT was also used to establish the assay reactivity threshold (RT). The application of the assay to sera from humans, Rhesus macaques and rabbits was demonstrated separately and by aggregate dilutional linearity analysis of the ED50 (slope=0.98, intercept=0.003, r(2)=0.989). We propose this TNA assay format with a qualified standard reference serum and customized interpretive software as a unifying platform technology for determination of functional serologic responses to anthrax vaccines and for evaluation of anthrax immunotherapeutics.
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Affiliation(s)
- Han Li
- Microbial Pathogenesis & Immune Response Laboratory, Meningitis and Vaccine Preventable Diseases Branch, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, United States
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