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Georgopoulos AP, James LM. Anthrax Vaccines in the 21st Century. Vaccines (Basel) 2024; 12:159. [PMID: 38400142 PMCID: PMC10892718 DOI: 10.3390/vaccines12020159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/24/2024] [Accepted: 01/30/2024] [Indexed: 02/25/2024] Open
Abstract
Vaccination against Bacillus anthracis is the best preventive measure against the development of deadly anthrax disease in the event of exposure to anthrax either as a bioweapon or in its naturally occurring form. Anthrax vaccines, however, have historically been plagued with controversy, particularly related to their safety. Fortunately, recent improvements in anthrax vaccines have been shown to confer protection with reduced short-term safety concerns, although questions about long-term safety remain. Here, we (a) review recent and ongoing advances in anthrax vaccine development, (b) emphasize the need for thorough characterization of current (and future) vaccines, (c) bring to focus the importance of host immunogenetics as the ultimate determinant of successful antibody production and protection, and (d) discuss the need for the systematic, active, and targeted monitoring of vaccine recipients for possible Chronic Multisymptom Illness (CMI).
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Affiliation(s)
- Apostolos P. Georgopoulos
- The Gulf War Illness Working Group, Brain Sciences Center, Department of Veterans Affairs Health Care System, Minneapolis, MN 55417, USA;
- Department of Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA
- Department of Psychiatry, University of Minnesota Medical School, Minneapolis, MN 55455, USA
- Department of Neurology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Lisa M. James
- The Gulf War Illness Working Group, Brain Sciences Center, Department of Veterans Affairs Health Care System, Minneapolis, MN 55417, USA;
- Department of Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA
- Department of Psychiatry, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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2
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Dyson EH, Simpson AJH, Gwyther RJ, Cuthbertson H, Patient DH, Matheson M, Gregg A, Hepburn MJ, Hallis B, Williamson ED. Serological responses to Anthrax Vaccine Precipitated (AVP) increase with time interval between booster doses. Vaccine 2022; 40:6163-6178. [PMID: 36153153 DOI: 10.1016/j.vaccine.2022.08.052] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 08/09/2022] [Accepted: 08/23/2022] [Indexed: 10/14/2022]
Abstract
We undertook a Phase 4 clinical trial to assess the effect of time interval between booster doses on serological responses to AVP. The primary objective was to evaluate responses to a single booster dose in two groups of healthy adults who had previously received a complete 4-dose primary course. Group A had received doses on schedule while Group B had not had one for ≥2 years. Secondary objectives were to evaluate the safety and tolerability of AVP booster doses, and to gain information on correlates of protection to aid future anthrax vaccine development. Blood samples were taken on Day 1 before dosing, and on Days 8, 15, 29 and 120, to measure Toxin Neutralisation Assay (TNA) NF50 values and concentrations of IgG antibodies against Protective Antigen (PA), Lethal Factor (LF) and Edema Factor (EF) by ELISA. For each serological parameter, fold changes from baseline following the trial AVP dose were greater in Group B than Group A at every time-point studied. Peak responses correlated positively with time since last AVP dose (highest values being observed after intervals of ≥10 years), and negatively with number of previous doses (highest values occurring in individuals who had received a primary course only). In 2017, having reviewed these results, the Joint Committee on Vaccination and Immunisation (JCVI) updated UK anthrax vaccination guidelines, extending the interval between routine AVP boosters from one to 10 years. Booster doses of AVP induce significant IgG responses against the three anthrax toxin components, particularly PA and LF. Similarly high responses were observed in TNA, a recognised surrogate for anthrax vaccine efficacy. Analysis of the 596 TNA results showed that anti-PA and anti-LF IgG make substantial independent contributions to neutralisation of anthrax lethal toxin. AVP may therefore have advantages over anthrax vaccines that depend on generating immunity to PA alone.
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Affiliation(s)
- E Hugh Dyson
- Defence Science and Technology Laboratory (DSTL), Porton Down, Salisbury, UK.
| | - Andrew J H Simpson
- Defence Science and Technology Laboratory (DSTL), Porton Down, Salisbury, UK.
| | - Robert J Gwyther
- Defence Science and Technology Laboratory (DSTL), Porton Down, Salisbury, UK.
| | - Hannah Cuthbertson
- UK Health Security Agency (UKHSA), formerly Public Health England (PHE), Porton Down, Salisbury, UK.
| | - Dawn H Patient
- Defence Science and Technology Laboratory (DSTL), Porton Down, Salisbury, UK.
| | - Mary Matheson
- UK Health Security Agency (UKHSA), formerly Public Health England (PHE), Porton Down, Salisbury, UK.
| | - Anya Gregg
- UK Health Security Agency (UKHSA), formerly Public Health England (PHE), Porton Down, Salisbury, UK.
| | - Matthew J Hepburn
- Defence Science and Technology Laboratory (DSTL), Porton Down, Salisbury, UK; US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, MD, USA.
| | - Bassam Hallis
- UK Health Security Agency (UKHSA), formerly Public Health England (PHE), Porton Down, Salisbury, UK.
| | - E Diane Williamson
- Defence Science and Technology Laboratory (DSTL), Porton Down, Salisbury, UK.
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Smith K, Garman L, Norris K, Muther J, Duke A, Engler RJM, Nelson MR, Collins LC, Spooner C, Guthridge C, James JA. Insufficient Anthrax Lethal Toxin Neutralization Is Associated with Antibody Subclass and Domain Specificity in the Plasma of Anthrax-Vaccinated Individuals. Microorganisms 2021; 9:microorganisms9061204. [PMID: 34199431 PMCID: PMC8229884 DOI: 10.3390/microorganisms9061204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 05/25/2021] [Accepted: 05/28/2021] [Indexed: 11/17/2022] Open
Abstract
Anthrax vaccine adsorbed (AVA) is a significant line of defense against bioterrorist attack from Bacillus anthracis spores. However, in a subset of individuals, this vaccine may produce a suboptimal quantity of anti-protective antigen (PA), antibodies that are poorly neutralizing, and/or antibody titers that wane over time, necessitating annual boosters. To study individuals with such poor responses, we examine the properties of anti-PA in a subset of vaccinated individuals that make significant quantities of antibody but are still unable to neutralize toxin. In this cohort, characterized by poorly neutralizing antibody, we find that increased IgG4 to IgG1 subclass ratios, low antibody avidity, and insufficient antibody targeting domain 4 associate with improper neutralization. Thus, future vaccines and vaccination schedules should be formulated to improve these deficiencies.
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Affiliation(s)
- Kenneth Smith
- Department of Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, 825 NE 13th St., Oklahoma City, OK 73104, USA; (K.N.); (J.M.); (A.D.); (C.G.)
- Correspondence: (K.S.); (J.A.J.); Tel.: +1-405-271-3275 (K.S.); +1-405-271-4987 (J.A.J.)
| | - Lori Garman
- Department of Genes and Human Disease, Oklahoma Medical Research Foundation, 825 NE 13th St., Oklahoma City, OK 73104, USA;
| | - Kathleen Norris
- Department of Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, 825 NE 13th St., Oklahoma City, OK 73104, USA; (K.N.); (J.M.); (A.D.); (C.G.)
| | - Jennifer Muther
- Department of Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, 825 NE 13th St., Oklahoma City, OK 73104, USA; (K.N.); (J.M.); (A.D.); (C.G.)
| | - Angie Duke
- Department of Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, 825 NE 13th St., Oklahoma City, OK 73104, USA; (K.N.); (J.M.); (A.D.); (C.G.)
| | - Renata J. M. Engler
- Walter Reed National Military Medical Center, 8901 Wisconsin Ave, Bethesda, MD 20814, USA; (R.J.M.E.); (M.R.N.); (L.C.C.); (C.S.)
| | - Michael R. Nelson
- Walter Reed National Military Medical Center, 8901 Wisconsin Ave, Bethesda, MD 20814, USA; (R.J.M.E.); (M.R.N.); (L.C.C.); (C.S.)
| | - Limone C. Collins
- Walter Reed National Military Medical Center, 8901 Wisconsin Ave, Bethesda, MD 20814, USA; (R.J.M.E.); (M.R.N.); (L.C.C.); (C.S.)
| | - Christina Spooner
- Walter Reed National Military Medical Center, 8901 Wisconsin Ave, Bethesda, MD 20814, USA; (R.J.M.E.); (M.R.N.); (L.C.C.); (C.S.)
| | - Carla Guthridge
- Department of Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, 825 NE 13th St., Oklahoma City, OK 73104, USA; (K.N.); (J.M.); (A.D.); (C.G.)
| | - Judith A. James
- Department of Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, 825 NE 13th St., Oklahoma City, OK 73104, USA; (K.N.); (J.M.); (A.D.); (C.G.)
- Department of Microbiology and Immunology, Oklahoma University Health Science Center, 940 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
- Departments of Medicine and Pathology, Oklahoma University Health Science Center, 1000 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
- Correspondence: (K.S.); (J.A.J.); Tel.: +1-405-271-3275 (K.S.); +1-405-271-4987 (J.A.J.)
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4
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Gallagher TB, Mellado-Sanchez G, Jorgensen AL, Moore S, Nataro JP, Pasetti MF, Baillie LW. Development of a multiple-antigen protein fusion vaccine candidate that confers protection against Bacillus anthracis and Yersinia pestis. PLoS Negl Trop Dis 2019; 13:e0007644. [PMID: 31430284 PMCID: PMC6716679 DOI: 10.1371/journal.pntd.0007644] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 08/30/2019] [Accepted: 07/19/2019] [Indexed: 12/25/2022] Open
Abstract
Bacillus anthracis and Yersinia pestis are zoonotic bacteria capable of causing severe and sometimes fatal infections in animals and humans. Although considered as diseases of antiquity in industrialized countries due to animal and public health improvements, they remain endemic in vast regions of the world disproportionally affecting the poor. These pathogens also remain a serious threat if deployed in biological warfare. A single vaccine capable of stimulating rapid protection against both pathogens would be an extremely advantageous public health tool. We produced multiple-antigen fusion proteins (MaF1 and MaF2) containing protective regions from B. anthracis protective antigen (PA) and lethal factor (LF), and from Y. pestis V antigen (LcrV) and fraction 1 (F1) capsule. The MaF2 sequence was also expressed from a plasmid construct (pDNA-MaF2). Immunogenicity and protective efficacy were investigated in mice following homologous and heterologous prime-boost immunization. Antibody responses were determined by ELISA and anthrax toxin neutralization assay. Vaccine efficacy was determined against lethal challenge with either anthrax toxin or Y. pestis. Both constructs elicited LcrV and LF-specific serum IgG, and MaF2 elicited toxin-neutralizing antibodies. Immunizations with MaF2 conferred 100% and 88% protection against Y. pestis and anthrax toxin, respectively. In contrast, pDNA-MaF2 conferred only 63% protection against Y. pestis and no protection against anthrax toxin challenge. pDNA-MaF2-prime MaF2-boost induced 75% protection against Y. pestis and 25% protection against anthrax toxin. Protection was increased by the molecular adjuvant CARDif. In conclusion, MaF2 is a promising multi-antigen vaccine candidate against anthrax and plague that warrants further investigation. Anthrax and plague are ancient infectious diseases that continue to affect people living in poor, endemic regions and to threaten industrialized nations due to their potential use in biowarfare. Candidate vaccines need improvement to minimize non-desirable effects and increase their efficacy. The purpose of this work was to develop and evaluate a single subunit vaccine capable of conferring protection against Bacillus anthracis and Yersinia pestis. To this end, specific regions from their genome or key protective protein sequences from both microorganisms were combined to obtain either recombinant plasmids or recombinant proteins and tested as vaccine candidates in mice. The recombinant protein MaF2 induced specific antibody responses and afforded full and partial protection against Y. pestis and B. anthracis, respectively. Meanwhile, the DNA vaccine equivalent to MaF2 conferred only partial protection against Y. pestis, which increased when combined with an MaF2 protein boost. MaF2 emerged as a promising dual pathogen recombinant vaccine that warrants further investigation.
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Affiliation(s)
- Theresa B. Gallagher
- Center for Vaccine Development and Global Health, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Gabriela Mellado-Sanchez
- Center for Vaccine Development and Global Health, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Ana L. Jorgensen
- Center for Vaccine Development and Global Health, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Stephen Moore
- BIOMET, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - James P. Nataro
- Department of Pediatrics, University of Virginia School of Medicine, Box, Charlottesville, VA, United States of America
| | - Marcela F. Pasetti
- Center for Vaccine Development and Global Health, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States of America
- * E-mail: (MFP); (LWB)
| | - Les W. Baillie
- The Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, Wales, United Kingdom
- * E-mail: (MFP); (LWB)
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Dumas EK, Garman L, Cuthbertson H, Charlton S, Hallis B, Engler RJM, Choudhari S, Picking WD, James JA, Farris AD. Lethal factor antibodies contribute to lethal toxin neutralization in recipients of anthrax vaccine precipitated. Vaccine 2017; 35:3416-3422. [PMID: 28504191 DOI: 10.1016/j.vaccine.2017.05.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 05/03/2017] [Indexed: 01/08/2023]
Abstract
A major difference between two currently licensed anthrax vaccines is presence (United Kingdom Anthrax Vaccine Precipitated, AVP) or absence (United States Anthrax Vaccine Adsorbed, AVA) of quantifiable amounts of the Lethal Toxin (LT) component Lethal Factor (LF). The primary immunogen in both vaccine formulations is Protective Antigen (PA), and LT-neutralizing antibodies directed to PA are an accepted correlate of vaccine efficacy; however, vaccination studies in animal models have demonstrated that LF antibodies can be protective. In this report we compared humoral immune responses in cohorts of AVP (n=39) and AVA recipients (n=78) matched 1:2 for number of vaccinations and time post-vaccination, and evaluated whether the LF response contributes to LT neutralization in human recipients of AVP. PA response rates (≥95%) and PA IgG concentrations were similar in both groups; however, AVP recipients exhibited higher LT neutralization ED50 values (AVP: 1464.0±214.7, AVA: 544.9±83.2, p<0.0001) and had higher rates of LF IgG positivity (95%) compared to matched AVA vaccinees (1%). Multiple regression analysis revealed that LF IgG makes an independent and additive contribution to the LT neutralization response in the AVP group. Affinity purified LF antibodies from two independent AVP recipients neutralized LT and bound to LF Domain 1, confirming contribution of LF antibodies to LT neutralization. This study documents the benefit of including an LF component to PA-based anthrax vaccines.
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Affiliation(s)
- Eric K Dumas
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation (OMRF), 825 NE 13th St., Oklahoma City, OK 73104, USA; Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center (OUHSC), 940 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
| | - Lori Garman
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation (OMRF), 825 NE 13th St., Oklahoma City, OK 73104, USA; Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center (OUHSC), 940 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
| | - Hannah Cuthbertson
- Public Health England, National Infection Service, Porton Down, Salisbury, Wiltshire SP4 0JG, United Kingdom
| | - Sue Charlton
- Public Health England, National Infection Service, Porton Down, Salisbury, Wiltshire SP4 0JG, United Kingdom
| | - Bassam Hallis
- Public Health England, National Infection Service, Porton Down, Salisbury, Wiltshire SP4 0JG, United Kingdom
| | - Renata J M Engler
- Walter Reed National Military Medical Center, 8901 Wisconsin Ave, Bethesda, MD 20814, USA
| | - Shyamal Choudhari
- Department of Pharmaceutical Chemistry, University of Kansas, 320B Multidisciplinary Research Building, 2030 Becker Dr., Lawrence, KS 66047, USA
| | - William D Picking
- Department of Pharmaceutical Chemistry, University of Kansas, 320B Multidisciplinary Research Building, 2030 Becker Dr., Lawrence, KS 66047, USA
| | - Judith A James
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation (OMRF), 825 NE 13th St., Oklahoma City, OK 73104, USA; Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center (OUHSC), 940 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA; Departments of Medicine and Pathology, OUHSC, 1000 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
| | - A Darise Farris
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation (OMRF), 825 NE 13th St., Oklahoma City, OK 73104, USA; Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center (OUHSC), 940 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA.
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6
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Head BM, Rubinstein E, Meyers AFA. Alternative pre-approved and novel therapies for the treatment of anthrax. BMC Infect Dis 2016; 16:621. [PMID: 27809794 PMCID: PMC5094018 DOI: 10.1186/s12879-016-1951-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 10/22/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bacillus anthracis, the causative agent of anthrax, is a spore forming and toxin producing rod-shaped bacterium that is classified as a category A bioterror agent. This pathogenic microbe can be transmitted to both animals and humans. Clinical presentation depends on the route of entry (direct contact, ingestion, injection or aerosolization) with symptoms ranging from isolated skin infections to more severe manifestations such as cardiac or pulmonary shock, meningitis, and death. To date, anthrax is treatable if antibiotics are administered promptly and continued for 60 days. However, if treatment is delayed or administered improperly, the patient's chances of survival are decreased drastically. In addition, antibiotics are ineffective against the harmful anthrax toxins and spores. Therefore, alternative therapeutics are essential. In this review article, we explore and discuss advances that have been made in anthrax therapy with a primary focus on alternative pre-approved and novel antibiotics as well as anti-toxin therapies. METHODS A literature search was conducted using the University of Manitoba search engine. Using this search engine allowed access to a greater variety of journals/articles that would have otherwise been restricted for general use. In order to be considered for discussion for this review, all articles must have been published later than 2009. RESULTS The alternative pre-approved antibiotics demonstrated high efficacy against B. anthracis both in vitro and in vivo. In addition, the safety profile and clinical pharmacology of these drugs were already known. Compounds that targeted underexploited bacterial processes (DNA replication, RNA synthesis, and cell division) were also very effective in combatting B. anthracis. In addition, these novel compounds prevented bacterial resistance. Targeting B. anthracis virulence, more specifically the anthrax toxins, increased the length of which treatment could be administered. CONCLUSIONS Several novel and pre-existing antibiotics, as well as toxin inhibitors, have shown increasing promise. A combination treatment that targets both bacterial growth and toxin production would be ideal and probably necessary for effectively combatting this armed bacterium.
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Affiliation(s)
- Breanne M. Head
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB R3E 0J9 Canada
| | - Ethan Rubinstein
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB R3E 0J9 Canada
| | - Adrienne F. A. Meyers
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB R3E 0J9 Canada
- National Laboratory for HIV Immunology, JC Wilt Infectious Disease Research Centre, Public Health Agency of Canada, Winnipeg, Canada
- Department of Medical Microbiology, University of Nairobi, Nairobi, Kenya
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Ascough S, Ingram RJ, Chu KKY, Musson JA, Moore SJ, Gallagher T, Baillie L, Williamson ED, Robinson JH, Maillere B, Boyton RJ, Altmann DM. CD4+ T Cells Targeting Dominant and Cryptic Epitopes from Bacillus anthracis Lethal Factor. Front Microbiol 2016; 6:1506. [PMID: 26779161 PMCID: PMC4700811 DOI: 10.3389/fmicb.2015.01506] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 12/14/2015] [Indexed: 12/31/2022] Open
Abstract
Anthrax is an endemic infection in many countries, particularly in the developing world. The causative agent, Bacillus anthracis, mediates disease through the secretion of binary exotoxins. Until recently, research into adaptive immunity targeting this bacterial pathogen has largely focused on the humoral response to these toxins. There is, however, growing recognition that cellular immune responses involving IFNγ producing CD4+ T cells also contribute significantly to a protective memory response. An established concept in adaptive immunity to infection is that during infection of host cells, new microbial epitopes may be revealed, leading to immune recognition of so called ‘cryptic’ or ‘subdominant’ epitopes. We analyzed the response to both cryptic and immunodominant T cell epitopes derived from the toxin component lethal factor and presented by a range of HLA-DR alleles. Using IFNγ-ELISpot assays we characterized epitopes that elicited a response following immunization with synthetic peptide and the whole protein and tested their capacities to bind purified HLA-DR molecules in vitro. We found that DR1 transgenics demonstrated T cell responses to a greater number of domain III cryptic epitopes than other HLA-DR transgenics, and that this pattern was repeated with the immunodominant epitopes, as a greater proportion of these epitopes induced a T cell response when presented within the context of the whole protein. Immunodominant epitopes LF457-476 and LF467-487 were found to induce a T cell response to the peptide, as well as to the whole native LF protein in DR1 and DR15, but not in DR4 transgenics. The analysis of Domain I revealed the presence of several unique cryptic epitopes all of which showed a strong to moderate relative binding affinity to HLA-DR4 molecules. However, none of the cryptic epitopes from either domain III or I displayed notably high binding affinities across all HLA-DR alleles assayed. These responses were influenced by the specific HLA alleles presenting the peptide, and imply that construction of future epitope string vaccines which are immunogenic across a wide range of HLA alleles could benefit from a combination of both cryptic and immunodominant anthrax epitopes.
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Affiliation(s)
| | - Rebecca J Ingram
- Centre for Infection and Immunity, Queen's University Belfast Belfast UK
| | - Karen K Y Chu
- Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London London, UK
| | - Julie A Musson
- Institute of Cellular Medicine, Newcastle University Newcastle upon Tyne, UK
| | - Stephen J Moore
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine Baltimore, MD, USA
| | - Theresa Gallagher
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine Baltimore, MD, USA
| | - Les Baillie
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University Cardiff, UK
| | | | - John H Robinson
- Institute of Cellular Medicine, Newcastle University Newcastle upon Tyne, UK
| | - Bernard Maillere
- Service d'Ingénierie Moléculaire des Protéines, Insititut de Biologie et de Technologies de Saclay, Commiseriat à l'Energie Atomique, Gif Sur Yvette France
| | - Rosemary J Boyton
- Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London London, UK
| | - Daniel M Altmann
- Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London London, UK
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Ascough S, Ingram RJ, Chu KK, Reynolds CJ, Musson JA, Doganay M, Metan G, Ozkul Y, Baillie L, Sriskandan S, Moore SJ, Gallagher TB, Dyson H, Williamson ED, Robinson JH, Maillere B, Boyton RJ, Altmann DM. Anthrax lethal factor as an immune target in humans and transgenic mice and the impact of HLA polymorphism on CD4+ T cell immunity. PLoS Pathog 2014; 10:e1004085. [PMID: 24788397 PMCID: PMC4006929 DOI: 10.1371/journal.ppat.1004085] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 03/07/2014] [Indexed: 11/23/2022] Open
Abstract
Bacillus anthracis produces a binary toxin composed of protective antigen (PA) and one of two subunits, lethal factor (LF) or edema factor (EF). Most studies have concentrated on induction of toxin-specific antibodies as the correlate of protective immunity, in contrast to which understanding of cellular immunity to these toxins and its impact on infection is limited. We characterized CD4+ T cell immunity to LF in a panel of humanized HLA-DR and DQ transgenic mice and in naturally exposed patients. As the variation in antigen presentation governed by HLA polymorphism has a major impact on protective immunity to specific epitopes, we examined relative binding affinities of LF peptides to purified HLA class II molecules, identifying those regions likely to be of broad applicability to human immune studies through their ability to bind multiple alleles. Transgenics differing only in their expression of human HLA class II alleles showed a marked hierarchy of immunity to LF. Immunogenicity in HLA transgenics was primarily restricted to epitopes from domains II and IV of LF and promiscuous, dominant epitopes, common to all HLA types, were identified in domain II. The relevance of this model was further demonstrated by the fact that a number of the immunodominant epitopes identified in mice were recognized by T cells from humans previously infected with cutaneous anthrax and from vaccinated individuals. The ability of the identified epitopes to confer protective immunity was demonstrated by lethal anthrax challenge of HLA transgenic mice immunized with a peptide subunit vaccine comprising the immunodominant epitopes that we identified. Anthrax is of concern with respect to human exposure in endemic regions, concerns about bioterrorism and the considerable global burden of livestock infections. The immunology of this disease remains poorly understood. Vaccination has been based on B. anthracis filtrates or attenuated spore-based vaccines, with more recent trials of next-generation recombinant vaccines. Approaches generally require extensive vaccination regimens and there have been concerns about immunogenicity and adverse reactions. An ongoing need remains for rationally designed, effective and safe anthrax vaccines. The importance of T cell stimulating vaccines is inceasingly recognized. An essential step is an understanding of immunodominant epitopes and their relevance across the diverse HLA immune response genes of human populations. We characterized CD4 T cell immunity to anthrax Lethal Factor (LF), using HLA transgenic mice, as well as testing candidate peptide epitopes for binding to a wide range of HLA alleles. We identified anthrax epitopes, noteworthy in that they elicit exceptionally strong immunity with promiscuous binding across multiple HLA alleles and isotypes. T cell responses in humans exposed to LF through either natural anthrax infection or vaccination were also examined. Epitopes identified as candidates were used to protect HLA transgenic mice from anthrax challenge.
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Affiliation(s)
- Stephanie Ascough
- Department of Medicine, Imperial College London, London, United Kingdom
| | - Rebecca J. Ingram
- Centre for Infection and Immunity, Queen's University Belfast, Belfast, United Kingdom
| | - Karen K. Chu
- Department of Medicine, Imperial College London, London, United Kingdom
| | | | - Julie A. Musson
- Institute for Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Mehmet Doganay
- Department of Infectious Disease, Erciyes University Hospital, Kayseri, Turkey
| | - Gökhan Metan
- Department of Infectious Disease, Erciyes University Hospital, Kayseri, Turkey
| | - Yusuf Ozkul
- Department of Medical Genetics, Erciyes University Hospital, Kayseri, Turkey
| | - Les Baillie
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom
| | | | - Stephen J. Moore
- BIOMET, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Theresa B. Gallagher
- BIOMET, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Hugh Dyson
- Defence Science Technology Laboratory, Porton Down, Salisbury, United Kingdom
| | - E. Diane Williamson
- Defence Science Technology Laboratory, Porton Down, Salisbury, United Kingdom
| | - John H. Robinson
- Institute for Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Bernard Maillere
- CEA, iBiTecS, Service d'Ingénierie Moléculaire des Protéines (SIMOPRO), Gif Sur Yvette, France
| | | | - Daniel M. Altmann
- Department of Medicine, Imperial College London, London, United Kingdom
- * E-mail:
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Rezaee M, Honari H, Kooshk MRA. Cloning, expression and purification of binding domains of lethal factor and protective antigen of Bacillus anthracis in Escherichia coli and evaluation of their related murine antibody. Mol Biol Rep 2014; 41:2445-52. [PMID: 24430302 DOI: 10.1007/s11033-014-3099-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 01/04/2014] [Indexed: 11/25/2022]
Abstract
Anthrax is common disease between human and animals caused by Bacillus anthracis. The cell binding domain of protective antigen (PAD4) and the binding domain of lethal factor (LFD1) have high immunogenicity potential and always were considered as a vaccine candidate against anthrax. The aims of this study are cloning and expressing of PAD4 and LFD1 in Escherichia coli, purification of the recombinant proteins and determination of their immunogenicity through evaluating of the relative produced polyclonal antibodies in mice. PAD4 and LFD1 genes were cloned in pET28a(+) vector and expressed in E. coli Bl21(DE3)PlysS. Expression and purification of the two recombinant proteins were confirmed by SDS-PAGE and Western blotting techniques. The PAD4 and LFD1 were purified using Ni(+)-NTA affinity chromatography (95-98 %), yielding 37.5 and 45 mg/l of culture, respectively. The antigens were injected three times into mice and production of relative antibodies was evaluated by ELISA test. The results showed that both PAD4 and LFD1 are immunogenic, but LFD1 has higher potential to stimulate Murine immune system. With regard to the high level of LFD1 and PAD4 expression and also significant increment in produced polyclonal antibodies, these recombinant proteins can be considered as a recombinant vaccine candidate against anthrax.
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Affiliation(s)
- Mehdi Rezaee
- Faculty of Basic Sciences, Biology Research Center, Imam Hossein University, Tehran, Iran
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10
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Tournier JN, Ulrich RG, Quesnel-Hellmann A, Mohamadzadeh M, Stiles BG. Anthrax, toxins and vaccines: a 125-year journey targetingBacillus anthracis. Expert Rev Anti Infect Ther 2014; 7:219-36. [DOI: 10.1586/14787210.7.2.219] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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11
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Combinations of monoclonal antibodies to anthrax toxin manifest new properties in neutralization assays. Infect Immun 2013; 81:1880-8. [PMID: 23509144 DOI: 10.1128/iai.01328-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Monoclonal antibodies (MAbs) are potential therapeutic agents against Bacillus anthracis toxins, since there is no current treatment to counteract the detrimental effects of toxemia. In hopes of isolating new protective MAbs to the toxin component lethal factor (LF), we used a strain of mice (C57BL/6) that had not been used in previous studies, generating MAbs to LF. Six LF-binding MAbs were obtained, representing 3 IgG isotypes and one IgM. One MAb (20C1) provided protection from lethal toxin (LeTx) in an in vitro mouse macrophage system but did not provide significant protection in vivo. However, the combination of two MAbs to LF (17F1 and 20C1) provided synergistic increases in protection both in vitro and in vivo. In addition, when these MAbs were mixed with MAbs to protective antigen (PA) previously generated in our laboratory, these MAb combinations produced synergistic toxin neutralization in vitro. But when 17F1 was combined with another MAb to LF, 19C9, the combination resulted in enhanced lethal toxicity. While no single MAb to LF provided significant toxin neutralization, LF-immunized mice were completely protected from infection with B. anthracis strain Sterne, which suggested that a polyclonal response is required for effective toxin neutralization. In total, these studies show that while a single MAb against LeTx may not be effective, combinations of multiple MAbs may provide the most effective form of passive immunotherapy, with the caveat that these may demonstrate emergent properties with regard to protective efficacy.
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12
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Cote CK, Kaatz L, Reinhardt J, Bozue J, Tobery SA, Bassett AD, Sanz P, Darnell SC, Alem F, O'Brien AD, Welkos SL. Characterization of a multi-component anthrax vaccine designed to target the initial stages of infection as well as toxaemia. J Med Microbiol 2012; 61:1380-1392. [PMID: 22767539 DOI: 10.1099/jmm.0.045393-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Current vaccine approaches to combat anthrax are effective; however, they target only a single protein [the protective antigen (PA) toxin component] that is produced after spore germination. PA production is subsequently increased during later vegetative cell proliferation. Accordingly, several aspects of the vaccine strategy could be improved. The inclusion of spore-specific antigens with PA could potentially induce protection to initial stages of the disease. Moreover, adding other epitopes to the current vaccine strategy will decrease the likelihood of encountering a strain of Bacillus anthracis (emerging or engineered) that is refractory to the vaccine. Adding recombinant spore-surface antigens (e.g. BclA, ExsFA/BxpB and p5303) to PA has been shown to augment protection afforded by the latter using a challenge model employing immunosuppressed mice challenged with spores derived from the attenuated Sterne strain of B. anthracis. This report demonstrated similar augmentation utilizing guinea pigs or mice challenged with spores of the fully virulent Ames strain or a non-toxigenic but encapsulated ΔAmes strain of B. anthracis, respectively. Additionally, it was shown that immune interference did not occur if optimal amounts of antigen were administered. By administering the toxin and spore-based immunogens simultaneously, a significant adjuvant effect was also observed in some cases. Thus, these data further support the inclusion of recombinant spore antigens in next-generation anthrax vaccine strategies.
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Affiliation(s)
- C K Cote
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - L Kaatz
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - J Reinhardt
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - J Bozue
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - S A Tobery
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - A D Bassett
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - P Sanz
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - S C Darnell
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - F Alem
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - A D O'Brien
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - S L Welkos
- Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
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13
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Hicks CW, Sweeney DA, Cui X, Li Y, Eichacker PQ. An overview of anthrax infection including the recently identified form of disease in injection drug users. Intensive Care Med 2012; 38:1092-104. [PMID: 22527064 DOI: 10.1007/s00134-012-2541-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 02/14/2012] [Indexed: 02/06/2023]
Abstract
PURPOSE Bacillus anthracis infection (anthrax) can be highly lethal. Two recent outbreaks related to contaminated mail in the USA and heroin in the UK and Europe and its potential as a bioterrorist weapon have greatly increased concerns over anthrax in the developed world. METHODS This review summarizes the microbiology, pathogenesis, diagnosis, and management of anthrax. RESULTS AND CONCLUSIONS Anthrax, a gram-positive bacterium, has typically been associated with three forms of infection: cutaneous, gastrointestinal, and inhalational. However, the anthrax outbreak among injection drug users has emphasized the importance of what is now considered a fourth disease form (i.e., injectional anthrax) that is characterized by severe soft tissue infection. While cutaneous anthrax is most common, its early stages are distinct and prompt appropriate treatment commonly produces a good outcome. However, early symptoms with the other three disease forms can be nonspecific and mistaken for less lethal conditions. As a result, patients with gastrointestinal, inhalational, or injectional anthrax may have advanced infection at presentation that can be highly lethal. Once anthrax is suspected, the diagnosis can usually be made with gram stain and culture from blood or tissue followed by confirmatory testing (e.g., PCR). While antibiotics are the mainstay of anthrax treatment, use of adjunctive therapies such as anthrax toxin antagonists are a consideration. Prompt surgical therapy appears to be important for successful management of injectional anthrax.
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Affiliation(s)
- Caitlin W Hicks
- Cleveland Clinic Lerner College of Medicine, Cleveland, OH 44122, USA
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14
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Crowe SR, Garman L, Engler RJ, Farris AD, Ballard JD, Harley JB, James JA. Anthrax vaccination induced anti-lethal factor IgG: fine specificity and neutralizing capacity. Vaccine 2011; 29:3670-8. [PMID: 21420416 PMCID: PMC3233230 DOI: 10.1016/j.vaccine.2011.03.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 02/24/2011] [Accepted: 03/03/2011] [Indexed: 10/18/2022]
Abstract
The efficacy biomarker of the currently licensed anthrax vaccine (AVA) is based on quantity and neutralizing capacity of anti-protective antigen (anti-PA) antibodies. However, animal studies have demonstrated that antibodies to lethal factor (LF) can provide protection against in vivo bacterial spore challenges. Improved understanding of the fine specificities of humoral immune responses that provide optimum neutralization capacity may enhance the efficacy of future passive immune globulin preparations to treat and prevent inhalation anthrax morbidity and mortality. This study (n=1000) was designed to identify AVA vaccinated individuals who generate neutralizing antibodies and to determine what specificities correlate with protection. The number of vaccine doses, years post vaccination, and PA titer were associated with in vitro neutralization, reinforcing previous reports. In addition, African American individuals had lower serologic neutralizing activity than European Americans, suggesting a genetic role in the generation of these neutralizing antibodies. Of the vaccinated individuals, only 69 (6.9%) had moderate levels of anti-LF IgG compared to 244 (24.4%) with low and 687 (68.7%) with extremely low levels of IgG antibodies to LF. Using overlapping decapeptide analysis, we identified six common LF antigenic regions targeted by those individuals with moderate levels of antibodies to LF and high in vitro toxin neutralizing activity. Affinity purified antibodies directed against antigenic epitopes within the PA binding and ADP-ribotransferase-like domains of LF were able to protect mice against lethal toxin challenge. Findings from these studies have important implications for vaccine design and immunotherapeutic development.
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Affiliation(s)
- Sherry R. Crowe
- Oklahoma Medical Research Foundation, 825 N.E. 13 Street, Oklahoma City, OK, U.S.A. 73104
| | - Lori Garman
- Oklahoma Medical Research Foundation, 825 N.E. 13 Street, Oklahoma City, OK, U.S.A. 73104
- Oklahoma University Health Science Center, 1100 N. Lindsay, Oklahoma City, OK, U.S.A. 73104
| | - Renata J.M. Engler
- Vaccine Healthcare Centers (VHC) Network, Walter Reed Army Medical Center, Red Cross Building 41 Suite 021 PO Box 6900 Georgia Avenue, NW Washington, DC, U.S.A. 20012
| | - A. Darise Farris
- Oklahoma Medical Research Foundation, 825 N.E. 13 Street, Oklahoma City, OK, U.S.A. 73104
- Oklahoma University Health Science Center, 1100 N. Lindsay, Oklahoma City, OK, U.S.A. 73104
| | - Jimmy D. Ballard
- Oklahoma University Health Science Center, 1100 N. Lindsay, Oklahoma City, OK, U.S.A. 73104
| | - John B. Harley
- Oklahoma University Health Science Center, 1100 N. Lindsay, Oklahoma City, OK, U.S.A. 73104
- Cincinnati Children's Hospital Medical Center, 3333 Burnet, ML 4010, Cincinnati, OH, U.S.A. 45229
| | - Judith A. James
- Oklahoma Medical Research Foundation, 825 N.E. 13 Street, Oklahoma City, OK, U.S.A. 73104
- Oklahoma University Health Science Center, 1100 N. Lindsay, Oklahoma City, OK, U.S.A. 73104
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15
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Brenneman KE, Doganay M, Akmal A, Goldman S, Galloway DR, Mateczun AJ, Cross AS, Baillie LW. The early humoral immune response to Bacillus anthracis toxins in patients infected with cutaneous anthrax. ACTA ACUST UNITED AC 2011; 62:164-72. [PMID: 21401726 DOI: 10.1111/j.1574-695x.2011.00800.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Bacillus anthracis, the causative agent of anthrax, produces a tripartite toxin composed of two enzymatically active subunits, lethal factor (LF) and edema factor (EF), which, when associated with a cell-binding component, protective antigen (PA), form lethal toxin and edema toxin, respectively. In this preliminary study, we characterized the toxin-specific antibody responses observed in 17 individuals infected with cutaneous anthrax. The majority of the toxin-specific antibody responses observed following infection were directed against LF, with immunoglobulin G (IgG) detected as early as 4 days after the onset of symptoms in contrast to the later and lower EF- and PA-specific IgG responses. Unlike the case with infection, the predominant toxin-specific antibody response of those immunized with the US anthrax vaccine absorbed and UK anthrax vaccine precipitated licensed anthrax vaccines was directed against PA. We observed that the LF-specific human antibodies were, like anti-PA antibodies, able to neutralize toxin activity, suggesting the possibility that they may contribute to protection. We conclude that an antibody response to LF might be a more sensitive diagnostic marker of anthrax than to PA. The ability of human LF-specific antibodies to neutralize toxin activity supports the possible inclusion of LF in future anthrax vaccines.
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Affiliation(s)
- Karen E Brenneman
- Biological Defense Research Directorate, Naval Medical Research Center, Rockville, MD, USA
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16
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Bagheri V, Motamedi H, Shapouri MRS. An efficient fusion protein system for expression of Bacillus anthracis protective antigen as immunogenic and diagnostic antigen. ASIAN PAC J TROP MED 2010. [DOI: 10.1016/s1995-7645(10)60184-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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17
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Baillie LW, Huwar TB, Moore S, Mellado-Sanchez G, Rodriguez L, Neeson BN, Flick-Smith HC, Jenner DC, Atkins HS, Ingram RJ, Altmann DM, Nataro JP, Pasetti MF. An anthrax subunit vaccine candidate based on protective regions of Bacillus anthracis protective antigen and lethal factor. Vaccine 2010; 28:6740-8. [PMID: 20691267 DOI: 10.1016/j.vaccine.2010.07.075] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 07/08/2010] [Accepted: 07/21/2010] [Indexed: 10/19/2022]
Abstract
Studies have confirmed the key role of Bacillus anthracis protective antigen (PA) in the US and UK human anthrax vaccines. However, given the tripartite nature of the toxin, other components, including lethal factor (LF), are also likely to contribute to protection. We examined the antibody and T cell responses to PA and LF in human volunteers immunized with the UK anthrax vaccine (AVP). Individual LF domains were assessed for immunogenicity in mice when given alone or with PA. Based on the results obtained, a novel fusion protein comprising D1 of LF and the host cell-binding domain of PA (D4) was assessed for protective efficacy. Murine protection studies demonstrated that both full-length LF and D1 of LF conferred complete protection against a lethal intraperitoneal challenge with B. anthracis STI spores. Subsequent studies with the LFD1-PAD4 fusion protein showed a similar level of protection. LF is immunogenic in humans and is likely to contribute to the protection stimulated by AVP. A single vaccine comprising protective regions from LF and PA would simplify production and confer a broader spectrum of protection than that seen with PA alone.
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Affiliation(s)
- Les W Baillie
- Welsh School of Pharmacy, Cardiff University, King Edward VII Avenue, Cardiff, CF10 3NB, Wales, UK.
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18
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Crowe SR, Ash LL, Engler RJM, Ballard JD, Harley JB, Farris AD, James JA. Select human anthrax protective antigen epitope-specific antibodies provide protection from lethal toxin challenge. J Infect Dis 2010; 202:251-60. [PMID: 20533877 DOI: 10.1086/653495] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Bacillus anthracis remains a serious bioterrorism concern, and the currently licensed vaccine remains an incomplete solution for population protection from inhalation anthrax and has been associated with concerns regarding efficacy and safety. Thus, understanding how to generate long-lasting protective immunity with reduced immunizations or provide protection through postexposure immunotherapeutics are long-sought goals. Through evaluation of a large military cohort, we characterized the levels of antibodies against protective antigen and found that over half of anthrax vaccinees had low serum levels of in vitro toxin neutralization capacity. Using solid-phase epitope mapping and confirmatory assays, we identified several neutralization-associated humoral epitopes and demonstrated that select antipeptide responses mediated protection in vitro. Finally, passively transferred antibodies specific for select epitopes provided protection in an in vivo lethal toxin mouse model. Identification of these antigenic regions has important implications for vaccine design and the development of directed immunotherapeutics.
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Affiliation(s)
- Sherry R Crowe
- Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
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19
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Ingram RJ, Metan G, Maillere B, Doganay M, Ozkul Y, Kim LU, Baillie L, Dyson H, Williamson ED, Chu KK, Ascough S, Moore S, Huwar TB, Robinson JH, Sriskandan S, Altmann DM. Natural exposure to cutaneous anthrax gives long-lasting T cell immunity encompassing infection-specific epitopes. THE JOURNAL OF IMMUNOLOGY 2010; 184:3814-21. [PMID: 20208010 DOI: 10.4049/jimmunol.0901581] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
There has been a long history of defining T cell epitopes to track viral immunity and to design rational vaccines, yet few data of this type exist for bacterial infections. Bacillus anthracis, the causative agent of anthrax, is both an endemic pathogen in many regions and a potential biological warfare threat. T cell immunity in naturally infected anthrax patients has not previously been characterized, which is surprising given concern about the ability of anthrax toxins to subvert or ablate adaptive immunity. We investigated CD4 T cell responses in patients from the Kayseri region of Turkey who were previously infected with cutaneous anthrax. Responses to B. anthracis protective Ag and lethal factor (LF) were investigated at the protein, domain, and epitope level. Several years after antibiotic-treated anthrax infection, strong T cell memory was detectable, with no evidence of the expected impairment in specific immunity. Although serological responses to existing anthrax vaccines focus primarily on protective Ag, the major target of T cell immunity in infected individuals and anthrax-vaccinated donors was LF, notably domain IV. Some of these anthrax epitopes showed broad binding to several HLA class alleles, but others were more constrained in their HLA binding patterns. Of specific CD4 T cell epitopes targeted within LF domain IV, one is preferentially seen in the context of bacterial infection, as opposed to vaccination, suggesting that studies of this type will be important in understanding how the human immune system confronts serious bacterial infection.
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Affiliation(s)
- Rebecca J Ingram
- Department of Infectious Diseases and Immunity, Imperial College London, London, United Kingdom
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20
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Klinman DM, Yamamoto M, Tross D, Tomaru K. Anthrax prevention and treatment: utility of therapy combining antibiotic plus vaccine. Expert Opin Biol Ther 2010; 9:1477-86. [PMID: 19769541 DOI: 10.1517/14712590903307347] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The intentional release of anthrax spores in 2001 confirmed this pathogen's ability to cause widespread panic, morbidity and mortality. While individuals exposed to anthrax can be successfully treated with antibiotics, pre-exposure vaccination can reduce susceptibility to infection-induced illness. Concern over the safety and immunogenicity of the licensed US vaccine (Anthrax Vaccine Adsorbed (AVA)) has fueled research into alternatives. Second-generation anthrax vaccines based on purified recombinant protective antigen (rPA) have entered clinical trials. These rPA vaccines induce neutralizing antibodies that prevent illness, but the magnitude and duration of the resultant protective response is modest. Efforts are underway to bolster the immunogenicity of rPA by combining it with adjuvants and other immunostimulatory agents. Third generation vaccines are under development that utilize a wide variety of immunization platforms, antigens, adjuvants, delivery methods and routes of delivery to optimize the induction of a protective immunity. For the foreseeable future, vaccination will rely on first and second generation vaccines co-administered with immune adjuvants. Optimal post-exposure treatment of immunologically naive individuals should include a combination of vaccine plus antibiotic therapy.
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Affiliation(s)
- Dennis M Klinman
- National Cancer Institute (NCI), NCI, NIH, Frederick, MD 21702, USA.
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21
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Cybulski RJ, Sanz P, O'Brien AD. Anthrax vaccination strategies. Mol Aspects Med 2009; 30:490-502. [PMID: 19729034 DOI: 10.1016/j.mam.2009.08.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Accepted: 08/24/2009] [Indexed: 01/10/2023]
Abstract
The biological attack conducted through the US postal system in 2001 broadened the threat posed by anthrax from one pertinent mainly to soldiers on the battlefield to one understood to exist throughout our society. The expansion of the threatened population placed greater emphasis on the reexamination of how we vaccinate against Bacillus anthracis. The currently-licensed Anthrax Vaccine, Adsorbed (AVA) and Anthrax Vaccine, Precipitated (AVP) are capable of generating a protective immune response but are hampered by shortcomings that make their widespread use undesirable or infeasible. Efforts to gain US Food and Drug Administration (FDA) approval for licensure of a second generation recombinant protective antigen (rPA)-based anthrax vaccine are ongoing. However, this vaccine's reliance on the generation of a humoral immune response against a single virulence factor has led a number of scientists to conclude that the vaccine is likely not the final solution to optimal anthrax vaccine design. Other vaccine approaches, which seek a more comprehensive immune response targeted at multiple components of the B. anthracis organism, are under active investigation. This review seeks to summarize work that has been done to build on the current PA-based vaccine methodology and to evaluate the search for future anthrax prophylaxis strategies.
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Affiliation(s)
- Robert J Cybulski
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, United States
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22
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Abboud N, De Jesus M, Nakouzi A, Cordero RJB, Pujato M, Fiser A, Rivera J, Casadevall A. Identification of linear epitopes in Bacillus anthracis protective antigen bound by neutralizing antibodies. J Biol Chem 2009; 284:25077-86. [PMID: 19617628 DOI: 10.1074/jbc.m109.022061] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Protective antigen (PA), the binding subunit of anthrax toxin, is the major component in the current anthrax vaccine, but the fine antigenic structure of PA is not well defined. To identify linear neutralizing epitopes of PA, 145 overlapping peptides covering the entire sequence of the protein were synthesized. Six monoclonal antibodies (mAbs) and antisera from mice specific for PA were tested for their reactivity to the peptides by enzyme-linked immunosorbent assays. Three major linear immunodominant B-cell epitopes were mapped to residues Leu(156) to Ser(170), Val(196) to Ile(210), and Ser(312) to Asn(326) of the PA protein. Two mAbs with toxin-neutralizing activity recognized two different epitopes in close proximity to the furin cleavage site in domain 1. The three-dimensional complex structure of PA and its neutralizing mAbs 7.5G and 19D9 were modeled using the molecular docking method providing models for the interacting epitope and paratope residues. For both mAbs, LeTx neutralization was associated with interference with furin cleavage, but they differed in effectiveness depending on whether they bound on the N- or C-terminal aspect of the cleaved products. The two peptides containing these epitopes that include amino acids Leu(156)-Ser(170) and Val(196)-Ile(210) were immunogenic and elicited neutralizing antibody responses to PA. These results identify the first linear neutralizing epitopes of PA and show that peptides containing epitope sequences can elicit neutralizing antibody responses, a finding that could be exploited for vaccine design.
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Affiliation(s)
- Nareen Abboud
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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23
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Midha S, Bhatnagar R. Anthrax protective antigen administered by DNA vaccination to distinct subcellular locations potentiates humoral and cellular immune responses. Eur J Immunol 2009; 39:159-77. [PMID: 19130551 DOI: 10.1002/eji.200838058] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Based on the hypothesis that immune outcome can be influenced by the form of antigen administered and its ability to access various antigen-processing pathways, we targeted the 63 kDa fragment of protective antigen (PA) of Bacillus anthracis to various subcellular locations by DNA chimeras bearing a set of signal sequences. These targeting signals, namely, lysosome-associated membrane protein 1 (LAMP1), tissue plasminogen activator (TPA) and ubiquitin, encoded various forms of PA viz. lysosomal, secreted and cytosolic, respectively. Examination of IgG subclass distribution arising as a result of DNA vaccination indicated a higher IgG1:IgG2a ratio whenever the groups were immunized with chimeras bearing TPA, LAMP1 signals alone or when combined together. Importantly, high end-point titers of IgG antibodies were maintained until 24 wk. It was paralleled by high avidity toxin neutralizing antibodies (TNA) and effective cellular adaptive immunity in the systemic compartment. Anti-PA and TNA titers of approximately 10(5) and approximately 10(3), respectively, provided protection to approximately 90% of vaccinated animals in the group pTPA-PA63-LAMP1. A significant correlation was found between survival percentage and post-challenge anti-PA titers and TNA titers. Overall, immune kinetics pointed that differential processing through various compartments gave rise to qualitative differences in the immune response generated by various chimeras.
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Affiliation(s)
- Shuchi Midha
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
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24
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Zarebski LM, Vaughan K, Sidney J, Peters B, Grey H, Janda KD, Casadevall A, Sette A. Analysis of epitope information related to Bacillus anthracis and Clostridium botulinum. Expert Rev Vaccines 2008; 7:55-74. [PMID: 18251694 DOI: 10.1586/14760584.7.1.55] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We have reviewed the information about epitopes of immunological interest from Clostridium botulinum and Bacillus anthracis, by mining the Immune Epitope Database and Analysis Resource. For both pathogens, the vast majority of epitopes reported to date are derived from a single protein: the protective antigen of B. anthracis and the neurotoxin type A of C. botulinum. A detailed analysis of the data was performed to characterize the function, localization and conservancy of epitopes identified as neutralizing and/or protective. In order to broaden the scope of this analysis, we have also included data describing immune responses against defined fragments (over 50 amino acids long) of the relevant antigens. The scarce information on T-cell determinants and on epitopes from other antigens besides the toxins, highlights a gap in our knowledge and identifies areas for future research. Despite this, several distinct structures at the epitope and fragment level are described herein, which could be potential additions to future vaccines or targets of novel immunotherapeutics and diagnostic reagents.
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Affiliation(s)
- Laura M Zarebski
- Immune Epitope Database and Analysis Resource, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, CA 9203,7 USA.
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25
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The anthrax vaccine adsorbed vaccine generates protective antigen (PA)-Specific CD4+ T cells with a phenotype distinct from that of naive PA T cells. Infect Immun 2008; 76:4538-45. [PMID: 18678674 DOI: 10.1128/iai.00324-08] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cellular immune responses against protective antigen (PA) of Bacillus anthracis in subjects that received the anthrax vaccine adsorbed (AVA) vaccine were examined. Multiple CD4(+) T-cell epitopes within PA were identified by using tetramer-guided epitope mapping. PA-reactive CD4(+) T cells with a CD45RA(-) phenotype were also detected by direct ex vivo staining of peripheral blood mononuclear cells (PBMC) with PA-specific tetramers. Surprisingly, PA-specific T cells were also detected in PBMC of nonvaccinees after a single cycle of in vitro PA stimulation. However, PA-reactive CD4(+) T cells in nonvaccinees occurred at lower frequencies than those in vaccinees. The majority of PA-reactive T cells from nonvaccinees were CD45RA(+) and exhibited a Th0/Th1 cytokine profile. In contrast, phenotyping and cytokine profile analyses of PA-reactive CD4(+) T cells from vaccinees indicated that vaccination leads to commitment of PA-reactive T cells to a Th2 lineage, including generation of PA-specific, pre-Th2 central memory T cells. These results demonstrate that the current AVA vaccine is effective in skewing the development of PA CD4(+) T cells to the Th2 lineage. The data also demonstrated the feasibility of using class II tetramers to analyze CD4(+) cell responses and lineage development after vaccination.
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26
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Polymeric glycoconjugates protect and activate macrophages to promote killing of Bacillus cereus spores during phagocytosis. Glycoconj J 2008; 25:473-80. [DOI: 10.1007/s10719-007-9097-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Revised: 11/21/2007] [Accepted: 12/04/2007] [Indexed: 10/22/2022]
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27
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Hepburn MJ, Hugh Dyson E, Simpson AJH, Brenneman KE, Bailey N, Wilkinson L, Hornby R, Mateczun AJ, Bell MG, Baillie LWJ. Immune response to two different dosing schedules of the anthrax vaccine precipitated (AVP) vaccine. Vaccine 2007; 25:6089-97. [PMID: 17604880 DOI: 10.1016/j.vaccine.2007.05.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Revised: 05/09/2007] [Accepted: 05/12/2007] [Indexed: 11/18/2022]
Abstract
A pilot study compared the immune response of regular (0, 3, 6, 32 weeks) and extended (0, 10, 13, 32 weeks) schedules of the UK anthrax vaccine (anthrax vaccine precipitated, AVP). Concentrations of antibodies to protective antigen (PA) were higher (p<0.05) among recipients of the extended (n=7) versus regular schedule (n=6) at week 32, and 2 weeks after the second and third vaccinations. Toxin neutralisation assay levels and anti-lethal factor antibodies followed patterns similar to anti-PA antibodies. Extending the interval between the first two AVP vaccinations may produce a stronger immune response, but persistence of this effect needs further study.
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Affiliation(s)
- Matthew J Hepburn
- Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Wiltshire, United Kingdom.
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28
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Grunow R, Porsch-Ozcürümez M, Splettstoesser W, Buckendahl A, Hahn U, Beyer W, Böhm R, Huber M, vd Esche U, Bessler W, Frangoulidis D, Finke EJ. Monitoring of ELISA-reactive antibodies against anthrax protective antigen (PA), lethal factor (LF), and toxin-neutralising antibodies in serum of individuals vaccinated against anthrax with the PA-based UK anthrax vaccine. Vaccine 2007; 25:3679-83. [PMID: 17287051 DOI: 10.1016/j.vaccine.2007.01.056] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Revised: 12/07/2006] [Accepted: 01/11/2007] [Indexed: 11/20/2022]
Abstract
The human anthrax vaccines currently licensed contain the protective antigen (PA) of Bacillus anthracis as main antigen together with traces of some other bacillus components, e.g. lethal factor (LF). The present study aimed at monitoring the course of specific antibody titres against PA and LF by enzyme linked immunosorbent assays (ELISA), as well as the levels of toxin-neutralising antibodies, in 11 volunteers vaccinated with the human anthrax vaccine UK. After an initial seroconversion in all vaccinees, a significant reduction of both antibody titres against PA and LF, and of neutralising antibodies, was detected just prior to a vaccine boost 6 months after completion of the basic immunisation. Following the booster injection, titres increased again to levels comparable to those after the fourth immunisation. ELISA titres against PA correlated significantly with neutralising antibodies (r=0.816, p<0.001). Therefore, the less work- and time-consuming ELISA should be favoured to monitor the efficacy of an anthrax vaccination.
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Affiliation(s)
- Roland Grunow
- Institut fuer Mikrobiologie der Bundeswehr, D-80937 Munich, Germany.
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29
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Semenova VA, Schmidt DS, Taylor TH, Li H, Steward-Clark E, Soroka SD, Ballard MM, Quinn CP. Analysis of anti-protective antigen IgG subclass distribution in recipients of anthrax vaccine adsorbed (AVA) and patients with cutaneous and inhalation anthrax. Vaccine 2006; 25:1780-8. [PMID: 17229495 DOI: 10.1016/j.vaccine.2006.11.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Revised: 11/06/2006] [Accepted: 11/13/2006] [Indexed: 10/23/2022]
Abstract
The anti-PA IgG1, IgG2, IgG3, and IgG4 subclass responses to clinical anthrax and to different numbers of anthrax vaccine adsorbed (AVA, BioThrax) injections were determined in a cross-sectional study of sera from 63 vaccinees and 13 clinical anthrax patients. The data show that both vaccination with three AVA injections and clinical anthrax elicit anti-PA IgG1, IgG2, and IgG3 subclass responses. An anti-PA IgG4 response was detected in AVA recipients after the fourth injection. The anthrax lethal toxin (LTx) neutralization efficacy of sera from recipients who received 4 to > or =10 AVA injections did not vary significantly in relation to changes in distribution of anti-PA IgG1 and IgG4 subclasses.
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Affiliation(s)
- V A Semenova
- Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
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30
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Gubbins MJ, Berry JD, Corbett CR, Mogridge J, Yuan XY, Schmidt L, Nicolas B, Kabani A, Tsang RS. Production and characterization of neutralizing monoclonal antibodies that recognize an epitope in domain 2 of Bacillus anthracis protective antigen. ACTA ACUST UNITED AC 2006; 47:436-43. [PMID: 16872381 PMCID: PMC7110350 DOI: 10.1111/j.1574-695x.2006.00114.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Antibodies against the protective antigen (PA) of Bacillus anthracis play a key role in response to infection by this important pathogen. The aim of this study was to produce and characterize monoclonal antibodies (mAbs) specific for PA and to identify novel neutralizing epitopes. Three murine mAbs with high specificity and nanomolar affinity for B. anthracis recombinant protective antigen (rPA) were produced and characterized. Western immunoblot analysis, coupled with epitope mapping using overlapping synthetic peptides, revealed that these mAbs recognize a linear epitope within domain 2 of rPA. Neutralization assays demonstrate that these mAbs effectively neutralize lethal toxin in vitro.
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Affiliation(s)
- Michael J. Gubbins
- Division of Vaccine Preventable Diseases, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Jody D. Berry
- Emerging Bacterial Pathogens Division and Monoclonal Antibody Section, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
- Correspondence: Jody D. Berry, CSCHAH, 1015 Arlington St, Winnipeg, MB, Canada R3E 3R2. Tel.: +1 204 789 6063; fax: +1 204 789 5009; e-mail:
| | - Cindi R. Corbett
- Emerging Bacterial Pathogens Division and Monoclonal Antibody Section, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Jeremy Mogridge
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Xin Y. Yuan
- Emerging Bacterial Pathogens Division and Monoclonal Antibody Section, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Lisa Schmidt
- Division of Vaccine Preventable Diseases, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Brigitte Nicolas
- Emerging Bacterial Pathogens Division and Monoclonal Antibody Section, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Amin Kabani
- Bacteriology Section, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Raymond S. Tsang
- Division of Vaccine Preventable Diseases, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
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31
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Abstract
AIM Anthrax is caused by the bacterium Bacillus anthracis. Although primarily a disease of animals, it can also infect man, sometimes with fatal consequences. As a result of concerns over the illicit use of this organism, considerable effort is focussed on the development of therapies capable of conferring protection against anthrax. This brief review will describe the efforts being made to address these issues. METHODS AND RESULTS A review of the literature and the proceedings of the sixth international conference on anthrax, held in Santa Fe, USA in 2005 shows intense activity, but there has been as yet no real progress. While effective antibiotics, antitoxins and vaccines are available, concerns over their toxicity and the emergence of resistant strains have driven the development of second-generation products. The principal target for vaccine development is Protective Antigen (PA), the nontoxic cell-binding component of anthrax lethal toxin. While the recombinant products currently undergoing human clinical trials will offer considerable advantages in terms of reduced side effects and ease of production, they would still require multiple, needle-based dosing, and the inclusion of the adjuvant alum makes them expensive to administer and stockpile. To address these issues, researchers are developing vaccine formulations, which stimulate rapid protection following needle-free injection (nasal, oral or transcutaneous), and are stable at room temperature to facilitate stockpiling and mass vaccination programs. CONCLUSIONS An array of medical countermeasures targeting B. anthracis will become available over the next 5-10 years. SIGNIFICANCE AND IMPACT OF THE STUDY The huge investment of research dollars is expected to dramatically expand the knowledge base. A better understanding of basic issues, such as survival in nature and pathogenesis in humans, will facilitate the development of new modalities to eliminate the threat posed by this organism.
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Affiliation(s)
- L W J Baillie
- Biodefence Initiative, Medical Biotechnology Center, University of Maryland Biotechnology Institute, Baltimore, 21201, USA.
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32
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Kang TJ, Fenton MJ, Weiner MA, Hibbs S, Basu S, Baillie L, Cross AS. Murine macrophages kill the vegetative form of Bacillus anthracis. Infect Immun 2005; 73:7495-501. [PMID: 16239551 PMCID: PMC1273904 DOI: 10.1128/iai.73.11.7495-7501.2005] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Anti-protective antigen antibody was reported to enhance macrophage killing of ingested Bacillus anthracis spores, but it was unclear whether the antibody-mediated macrophage killing mechanism was directed against the spore itself or the vegetative form emerging from the ingested and germinating spore. To address this question, we compared the killing of germination-proficient (gp) and germination-deficient (DeltagerH) Sterne 34F2 strain spores by murine peritoneal macrophages. While macrophages similarly ingested both spores, only gp Sterne was killed at 5 h (0.37 log kill). Pretreatment of macrophages with gamma interferon (IFN-gamma) or opsonization with immunoglobulin G (IgG) isolated from a subject immunized with an anthrax vaccine enhanced the killing of Sterne to 0.49 and 0.73 log, respectively, but the combination of IFN-gamma and IgG was no better than either treatment alone. Under no condition was there killing of DeltagerH spores. To examine the ability of the exosporium to protect spores from macrophages, we compared the macrophage-mediated killing of nonsonicated (exosporium+) and sonicated (exosporium-) Sterne 34F2 spores. More sonicated spores than nonsonicated spores were killed at 5 h (0.98 versus 0.37 log kill, respectively). Pretreatment with IFN-gamma increased the sonicated spore killing to 1.39 log. However, the opsonization with IgG was no better than no treatment or pretreatment with IFN-gamma. We conclude that macrophages appear unable to kill the spore form of B. anthracis and that the exosporium may play a role in the protection of spores from macrophages.
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Affiliation(s)
- Tae Jin Kang
- Center for Vaccine Development, Department of Medicine, University of Maryland, 685 W. Baltimore Street, HSF I-480, Baltimore, MD 21201,USA
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33
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Abstract
Bacillus anthracis is a pathogen of animals which rarely infects humans. Its use as a bioweapon has stimulated efforts to develop genetic typing methods and therapeutics to respond to an attack. Of particular concern is the transfer of virulence genes from B. anthracis to other closely related strains of bacillus.
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Affiliation(s)
- L W J Baillie
- Medical Biotechnology Center, University of Maryland Biotechnology Institute, Baltimore, MD 21201, USA.
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34
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Abstract
The current human anthrax vaccines licensed in the US and UK consist of aluminum hydroxide-adsorbed or alum-precipitated culture supernatant material from fermentor cultures of toxigenic noncapsulated strains of Bacillus anthracis. The threat of B. anthracis being used as a biowarfare agent has led to a wider usage of these vaccines, which has heightened concerns regarding the need for frequent boosters and the occasional local reactogenicity associated with vaccination. These concerns have provided the impetus for the development of better characterized vaccines. This review summarizes the work of numerous laboratories in the search for alternative vaccines against anthrax that are well tolerated, provide long-lasting immunity, and are efficacious.
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Affiliation(s)
- Stephen F Little
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
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