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Sharma S, Bahl V, Srivastava G, Shamim R, Bhatnagar R, Gaur D. Recombinant full-length Bacillus Anthracis protective antigen and its 63 kDa form elicits protective response in formulation with addavax. Front Immunol 2023; 13:1075662. [PMID: 36713362 PMCID: PMC9877290 DOI: 10.3389/fimmu.2022.1075662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 12/16/2022] [Indexed: 01/14/2023] Open
Abstract
Introduction Bacillus anthracis is the causative agent for the lethal disease anthrax, primarily affecting animals and humans in close contact with an infected host. The pathogenicity of B. anthracis is attributed to the secreted exotoxins and their outer capsule. The host cell-binding exotoxin component "protective antigen" (PA) is reported to be a potent vaccine candidate. The aim of our study is to produce several PA constructs and analyze their vaccine potential. Methods We have designed the various subunit, PA-based recombinant proteins, i.e., full-length Protective antigen (PA-FL), C-terminal 63 kDa fragment (PA63), Protective antigen domain 1-domain 4 chimeras (PA-D1-4) and protective antigen domain 4 (PA-D4) and analyzed their vaccine potential with different human-compatible adjuvants in the mouse model. We have optimized the process and successfully expressed our recombinant antigens as soluble proteins, except full-length PA. All the recombinant antigen formulations with three different adjuvants i.e., Addavax, Alhydrogel, and Montanide ISA 720, were immunized in different mouse groups. The vaccine efficacy of the formulations was analyzed by mouse serum antigen-specific antibody titer, toxin neutralization assay, and survival analysis of mouse groups challenged with a lethal dose of B. anthracis virulent spores. Results We have demonstrated that the PA-FL addavax and PA63 addavax formulations were most effective in protecting spore-challenged mice and serum from the mice immunized with PAFL addavax, PA-FL alhydrogel, PA63 addavax, and PA63 alhydrogel formulations were equivalently efficient in neutralizing the anthrax lethal toxin. The higher levels of serum Th1, Th2, and Th17 cytokines in PA-FL addavax immunized mice correspond to the enhanced protection provided by the formulation in challenged mice. Discussion We have demonstrated that the PA-FL addavax and PA63 addavax formulations exhibit equivalent efficiency as vaccine formulation both in a mouse model of anthrax and mammalian cell lines. However, PA63 is a smaller antigen than PA-FL and more importantly, PA63 is expressed as a soluble protein in E. coli, which imparts a translational advantage to PA63-based formulation. Thus, the outcome of our study has significant implications for the development of protective antigen-based vaccine formulations for human use against the lethal disease anthrax.
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Affiliation(s)
- Shikhar Sharma
- Laboratory of Malaria & Vaccine Research, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India,Department of Oncology Science, University of Oklahoma Health Science Center, Oklahoma City, OK, United States,*Correspondence: Shikhar Sharma, ;
| | - Vanndita Bahl
- Laboratory of Malaria & Vaccine Research, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Gaurav Srivastava
- Food Technology Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
| | - Risha Shamim
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Rakesh Bhatnagar
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Deepak Gaur
- Laboratory of Malaria & Vaccine Research, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
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Firstova VV, Shakhova AS, Riabko AK, Silkina MV, Zeninskaya NA, Romanenko YO, Marin MA, Rogozin MM, Kartseva AS, Dyatlov IA, Shemyakin IG. Characterization of the adaptive immune response of donors receiving live anthrax vaccine. PLoS One 2021; 16:e0260202. [PMID: 34928976 PMCID: PMC8687594 DOI: 10.1371/journal.pone.0260202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 11/04/2021] [Indexed: 11/19/2022] Open
Abstract
Live anthrax vaccine containing spores from attenuated strains STI-1 of Bacillus anthracis is used in Russia and former CIS (Commonwealth of Independent States) to prevent anthrax. In this paper we studied the duration of circulation of antibodies specific to spore antigens, the protective antigen (PA), the lethal factor (LF) and their domains (D) in donors’ blood at different times after their immunization with live anthrax vaccine. The relationship between the toxin neutralization activity level and the level of antibodies to PA, LF and their domains was tested. The effect of age, gender and number of vaccinations on the level of adaptive post-vaccination immune response has been studied. It was shown that antibodies against PA-D1 circulate in the blood of donors for 1 year or more after immunization with live anthrax vaccine. Antibodies against all domains of LF and PA-D4 were detected in 11 months after vaccination. Antibodies against the spores were detected in 8 months after vaccination. A moderate positive correlation was found between the titers of antibodies to PA, LF, or their domains, and the TNA of the samples of blood serum from the donors.
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Affiliation(s)
- Victoria V. Firstova
- Laboratory of Molecular Biology, Federal Budget Institution of Science «State Research Center for Applied Microbiology and Biotechnology» of Federal Service of Consumer Right Surveillance & Human Welfare, Ministry of Health & Welfare, Obolensk, Moscow Region, Russian Federation
| | - Anastasia S. Shakhova
- Laboratory of Molecular Biology, Federal Budget Institution of Science «State Research Center for Applied Microbiology and Biotechnology» of Federal Service of Consumer Right Surveillance & Human Welfare, Ministry of Health & Welfare, Obolensk, Moscow Region, Russian Federation
| | - Alena K. Riabko
- Laboratory of Molecular Biology, Federal Budget Institution of Science «State Research Center for Applied Microbiology and Biotechnology» of Federal Service of Consumer Right Surveillance & Human Welfare, Ministry of Health & Welfare, Obolensk, Moscow Region, Russian Federation
- * E-mail:
| | - Marina V. Silkina
- Laboratory of Molecular Biology, Federal Budget Institution of Science «State Research Center for Applied Microbiology and Biotechnology» of Federal Service of Consumer Right Surveillance & Human Welfare, Ministry of Health & Welfare, Obolensk, Moscow Region, Russian Federation
| | - Natalia A. Zeninskaya
- Laboratory of Molecular Biology, Federal Budget Institution of Science «State Research Center for Applied Microbiology and Biotechnology» of Federal Service of Consumer Right Surveillance & Human Welfare, Ministry of Health & Welfare, Obolensk, Moscow Region, Russian Federation
| | - Yana O. Romanenko
- Laboratory of Molecular Biology, Federal Budget Institution of Science «State Research Center for Applied Microbiology and Biotechnology» of Federal Service of Consumer Right Surveillance & Human Welfare, Ministry of Health & Welfare, Obolensk, Moscow Region, Russian Federation
| | - Maksim A. Marin
- Laboratory of Molecular Biology, Federal Budget Institution of Science «State Research Center for Applied Microbiology and Biotechnology» of Federal Service of Consumer Right Surveillance & Human Welfare, Ministry of Health & Welfare, Obolensk, Moscow Region, Russian Federation
| | - Methun M. Rogozin
- Laboratory of Molecular Biology, Federal Budget Institution of Science «State Research Center for Applied Microbiology and Biotechnology» of Federal Service of Consumer Right Surveillance & Human Welfare, Ministry of Health & Welfare, Obolensk, Moscow Region, Russian Federation
| | - Alena S. Kartseva
- Laboratory of Molecular Biology, Federal Budget Institution of Science «State Research Center for Applied Microbiology and Biotechnology» of Federal Service of Consumer Right Surveillance & Human Welfare, Ministry of Health & Welfare, Obolensk, Moscow Region, Russian Federation
| | - Ivan A. Dyatlov
- Laboratory of Molecular Biology, Federal Budget Institution of Science «State Research Center for Applied Microbiology and Biotechnology» of Federal Service of Consumer Right Surveillance & Human Welfare, Ministry of Health & Welfare, Obolensk, Moscow Region, Russian Federation
| | - Igor G. Shemyakin
- Laboratory of Molecular Biology, Federal Budget Institution of Science «State Research Center for Applied Microbiology and Biotechnology» of Federal Service of Consumer Right Surveillance & Human Welfare, Ministry of Health & Welfare, Obolensk, Moscow Region, Russian Federation
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Kelly SM, Larsen KR, Darling R, Petersen AC, Bellaire BH, Wannemuehler MJ, Narasimhan B. Single-dose combination nanovaccine induces both rapid and durable humoral immunity and toxin neutralizing antibody responses against Bacillus anthracis. Vaccine 2021; 39:3862-3870. [PMID: 34090702 DOI: 10.1016/j.vaccine.2021.05.077] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/24/2021] [Accepted: 05/23/2021] [Indexed: 12/11/2022]
Abstract
Bacillus anthracis, the causative agent of anthrax, continues to be a prominent biological warfare and bioterrorism threat. Vaccination is likely to remain the most effective and user-friendly public health measure to counter this threat in the foreseeable future. The commercially available AVA BioThrax vaccine has a number of shortcomings where improvement would lead to a more practical and effective vaccine for use in the case of an exposure event. Identification of more effective adjuvants and novel delivery platforms is necessary to improve not only the effectiveness of the anthrax vaccine, but also enhance its shelf stability and ease-of-use. Polyanhydride particles have proven to be an effective platform at adjuvanting the vaccine-associated adaptive immune response as well as enhancing stability of encapsulated antigens. Another class of adjuvants, the STING pathway-targeting cyclic dinucleotides, have proven to be uniquely effective at inducing a beneficial inflammatory response that leads to the rapid induction of high titer antibodies post-vaccination capable of providing protection against bacterial pathogens. In this work, we evaluate the individual contributions of cyclic di-GMP (CDG), polyanhydride nanoparticles, and a combination thereof towards inducing neutralizing antibody (nAb) against the secreted protective antigen (PA) from B. anthracis. Our results show that the combination nanovaccine elicited rapid, high titer, and neutralizing IgG anti-PA antibody following single dose immunization that persisted for at least 108 DPI.
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Affiliation(s)
- Sean M Kelly
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States; Nanovaccine Institute, Ames, IA, United States
| | - Kristina R Larsen
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, United States; Interdepartmental Microbiology Program, Iowa State University, Ames, IA, United States
| | - Ross Darling
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, United States
| | - Andrew C Petersen
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, United States
| | - Bryan H Bellaire
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, United States; Interdepartmental Microbiology Program, Iowa State University, Ames, IA, United States; Nanovaccine Institute, Ames, IA, United States
| | - Michael J Wannemuehler
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, United States; Nanovaccine Institute, Ames, IA, United States.
| | - Balaji Narasimhan
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States; Nanovaccine Institute, Ames, IA, United States.
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Touhidinia M, Sefid F, Bidakhavidi M. Design of a Multi-epitope Vaccine Against Acinetobacter baumannii Using Immunoinformatics Approach. Int J Pept Res Ther 2021; 27:2417-2437. [PMID: 34483787 PMCID: PMC8397861 DOI: 10.1007/s10989-021-10262-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2021] [Indexed: 02/07/2023]
Abstract
Acinetobacter baumannii is one of the most successful pathogens causing nosocomial infections and has significantly multidrug-resistant. So far, there are no certain treatments to protect against infection with A. baumannii, therefore an effective A. baumannii vaccine needed. The purpose of this study was to predict antigenic epitopes of CarO protein for designing the A. baumannii vaccine using immunoinformatics analysis. CarO protein is one of the most important factors in the resistance against the antibiotic Carbapenem. In this study, T and B-cell epitopes of CarO protein were predicted and screened based on the antigenicity, toxicity, allergenicity features. The epitopes were linked by suitable linkers. Four different adjuvants were attached to the vaccine constructs which among them, vaccine construct 3 was chosen to predict the secondary and the 3D structure of the vaccine. The refinement process was performed to improve the quality of the 3D model structure; the validation process is performed using the Ramachandran plot and ProSA z-score. The designed vaccine's binding affinity to six various HLA molecules and TLR 2 and TLR4 were evaluated by molecular docking. Finally, in silico gene cloning was performed in the pET28a (+) vector. The findings suggest that the vaccine may be a promising vaccine to prevent A. baumannii infection.
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Affiliation(s)
- Maryam Touhidinia
- Department of Biology, Faculty of Science, Yazd University, Yazd, Iran
| | - Fatemeh Sefid
- Department of Medical Genetics, Shahid Sadoughi University of Medical Science, Yazd, Iran
- Department of Biology, Science and Art University, Yazd, Iran
| | - Mozhgan Bidakhavidi
- Department of Biology, Faculty of Science, Yazd University, Yazd, Iran
- Department of Nursing, Nursing and Midwifery Research, Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran
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5
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Alameh S, Bartolo G, O’Brien S, Henderson EA, Gonzalez LO, Hartmann S, Klimko CP, Shoe JL, Cote CK, Grill LK, Levitin A, Martchenko Shilman M. Anthrax toxin component, Protective Antigen, protects insects from bacterial infections. PLoS Pathog 2020; 16:e1008836. [PMID: 32866212 PMCID: PMC7458312 DOI: 10.1371/journal.ppat.1008836] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 07/24/2020] [Indexed: 01/23/2023] Open
Abstract
Anthrax is a major zoonotic disease of wildlife, and in places like West Africa, it can be caused by Bacillus anthracis in arid nonsylvatic savannahs, and by B. cereus biovar anthracis (Bcbva) in sylvatic rainforests. Bcbva-caused anthrax has been implicated in as much as 38% of mortality in rainforest ecosystems, where insects can enhance the transmission of anthrax-causing bacteria. While anthrax is well-characterized in mammals, its transmission by insects points to an unidentified anthrax-resistance mechanism in its vectors. In mammals, a secreted anthrax toxin component, 83 kDa Protective Antigen (PA83), binds to cell-surface receptors and is cleaved by furin into an evolutionary-conserved PA20 and a pore-forming PA63 subunits. We show that PA20 increases the resistance of Drosophila flies and Culex mosquitoes to bacterial challenges, without directly affecting the bacterial growth. We further show that the PA83 loop known to be cleaved by furin to release PA20 from PA63 is, in part, responsible for the PA20-mediated protection. We found that PA20 binds directly to the Toll activating peptidoglycan-recognition protein-SA (PGRP-SA) and that the Toll/NF-κB pathway is necessary for the PA20-mediated protection of infected flies. This effect of PA20 on innate immunity may also exist in mammals: we show that PA20 binds to human PGRP-SA ortholog. Moreover, the constitutive activity of Imd/NF-κB pathway in MAPKK Dsor1 mutant flies is sufficient to confer the protection from bacterial infections in a manner that is independent of PA20 treatment. Lastly, Clostridium septicum alpha toxin protects flies from anthrax-causing bacteria, showing that other pathogens may help insects resist anthrax. The mechanism of anthrax resistance in insects has direct implications on insect-mediated anthrax transmission for wildlife management, and with potential for applications, such as reducing the sensitivity of pollinating insects to bacterial pathogens.
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Affiliation(s)
- Saleem Alameh
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Gloria Bartolo
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Summer O’Brien
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Elizabeth A. Henderson
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Leandra O. Gonzalez
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Stella Hartmann
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Christopher P. Klimko
- Bacteriology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, United States of America
| | - Jennifer L. Shoe
- Bacteriology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, United States of America
| | - Christopher K. Cote
- Bacteriology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, United States of America
| | - Laurence K. Grill
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Anastasia Levitin
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
- * E-mail: (AL); (MMS)
| | - Mikhail Martchenko Shilman
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
- * E-mail: (AL); (MMS)
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Progress towards the Development of a NEAT Vaccine for Anthrax II: Immunogen Specificity and Alum Effectiveness in an Inhalational Model. Infect Immun 2020; 88:IAI.00082-20. [PMID: 32393506 DOI: 10.1128/iai.00082-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 04/23/2020] [Indexed: 12/24/2022] Open
Abstract
Bacillus anthracis is the causative agent of anthrax disease, presents with high mortality, and has been at the center of bioweapon efforts. The only currently U.S. FDA-approved vaccine to prevent anthrax in humans is anthrax vaccine adsorbed (AVA), which is protective in several animal models and induces neutralizing antibodies against protective antigen (PA), the cell-binding component of anthrax toxin. However, AVA requires a five-course regimen to induce immunity, along with an annual booster, and is composed of undefined culture supernatants from a PA-secreting strain. In addition, it appears to be ineffective against strains that lack anthrax toxin. Here, we investigated a vaccine formulation consisting of recombinant proteins from a surface-localized heme transport system containing near-iron transporter (NEAT) domains and its efficacy as a vaccine for anthrax disease. The cocktail of five NEAT domains was protective against a lethal challenge of inhaled bacillus spores at 3 and 28 weeks after vaccination. The reduction of the formulation to three NEATs (IsdX1, IsdX2, and Bslk) was as effective as a five-NEAT domain cocktail. The adjuvant alum, approved for use in humans, was as protective as Freund's Adjuvant, and protective vaccination correlated with increased anti-NEAT antibody reactivity and reduced bacterial levels in organs. Finally, the passive transfer of anti-NEAT antisera reduced mortality and disease severity, suggesting the protective component is comprised of antibodies. Collectively, these results provide evidence that a vaccine based upon recombinant NEAT proteins should be considered in the development of a next-generation anthrax vaccine.
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de Oliveira FFM, Mamillapalli S, Gonti S, Brey RN, Li H, Schiffer J, Casadevall A, Bann JG. Binding of the von Willebrand Factor A Domain of Capillary Morphogenesis Protein 2 to Anthrax Protective Antigen Vaccine Reduces Immunogenicity in Mice. mSphere 2020; 5:e00556-19. [PMID: 31941807 PMCID: PMC6968648 DOI: 10.1128/msphere.00556-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 12/09/2019] [Indexed: 11/24/2022] Open
Abstract
Protective antigen (PA) is a component of anthrax toxin that can elicit toxin-neutralizing antibody responses. PA is also the major antigen in the current vaccine to prevent anthrax, but stability problems with recombinant proteins have complicated the development of new vaccines containing recombinant PA. The relationship between antigen physical stability and immunogenicity is poorly understood, but there are theoretical reasons to think that this parameter can affect immune responses. We investigated the immunogenicity of anthrax PA, in the presence and absence of the soluble von Willebrand factor A domain of the human form of receptor capillary morphogenesis protein 2 (sCMG2), to elicit antibodies to PA in BALB/c mice. Prior studies showed that sCMG2 stabilizes the 83-kDa PA structure to pH, chemical denaturants, temperature, and proteolysis and slows the hydrogen-deuterium exchange rate of histidine residues far from the binding interface. In contrast to a vaccine containing PA without adjuvant, we found that mice immunized with PA in stable complex with sCMG2 showed markedly reduced antibody responses to PA, including toxin-neutralizing antibodies and antibodies to domain 4, which correlated with fewer toxin-neutralizing antibodies. In contrast, mice immunized with PA in concert with a nonbinding mutant of sCMG2 (D50A) showed anti-PA antibody responses similar to those observed with PA alone. Our results suggest that addition of sCMG2 to a PA vaccine formulation is likely to result in a significantly diminished immune response, but we discuss the multitude of factors that could contribute to reduced immunogenicity.IMPORTANCE The anthrax toxin PA is the major immunogen in the current anthrax vaccine (anthrax vaccine adsorbed). Improving the anthrax vaccine for avoidance of a cold chain necessitates improvements in the thermodynamic stability of PA. We address how stabilizing PA using sCMG2 affects PA immunogenicity in BALB/c mice. Although the stability of PA is increased by binding to sCMG2, PA immunogenicity is decreased. This study emphasizes that, while binding of a ligand retains or improves conformational stability without affecting the native sequence, epitope recognition or processing may be affected, abrogating an effective immune response.
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Affiliation(s)
- Fabiana Freire Mendes de Oliveira
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | | | - Srinivas Gonti
- Department of Chemistry, Wichita State University, Wichita, Kansas, USA
| | | | - Han Li
- Division of Bacterial Disease, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Jarad Schiffer
- Division of Bacterial Disease, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - James G Bann
- Department of Chemistry, Wichita State University, Wichita, Kansas, USA
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Kondakova OA, Nikitin NA, Evtushenko EA, Ryabchevskaya EM, Atabekov JG, Karpova OV. Vaccines against anthrax based on recombinant protective antigen: problems and solutions. Expert Rev Vaccines 2019; 18:813-828. [PMID: 31298973 DOI: 10.1080/14760584.2019.1643242] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Introduction: Anthrax is a dangerous bio-terror agent because Bacillus anthracis spores are highly resilient and can be easily aerosolized and disseminated. There is a threat of deliberate use of anthrax spores aerosol that could lead to serious fatal diseases outbreaks. Existing control measures against inhalation form of the disease are limited. All of this has provided an impetus to the development of new generation vaccines. Areas сovered: This review is devoted to challenges and achievements in the design of vaccines based on the anthrax recombinant protective antigen (rPA). Scientific databases have been searched, focusing on causes of PA instability and solutions to this problem, including new approaches of rPA expression, novel rPA-based vaccines formulations as well as the simultaneous usage of PA with other anthrax antigens. Expert opinion: PA is a central anthrax toxin component, playing a key role in the defense against encapsulated and unencapsulated strains. Subunit rPA-based vaccines have a good safety and protective profile. However, there are problems of PA instability that are greatly enhanced when using aluminum adjuvants. New adjuvant compositions, dry formulations and resistant to proteolysis and deamidation mutant PA forms can help to handle this issue. Devising a modern anthrax vaccine requires huge efforts.
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Affiliation(s)
- Olga A Kondakova
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
| | - Nikolai A Nikitin
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
| | - Ekaterina A Evtushenko
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
| | - Ekaterina M Ryabchevskaya
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
| | - Joseph G Atabekov
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
| | - Olga V Karpova
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
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Guimarães AJ, de Cerqueira MD, Zamith-Miranda D, Lopez PH, Rodrigues ML, Pontes B, Viana NB, DeLeon-Rodriguez CM, Rossi DCP, Casadevall A, Gomes AMO, Martinez LR, Schnaar RL, Nosanchuk JD, Nimrichter L. Host membrane glycosphingolipids and lipid microdomains facilitate Histoplasma capsulatum internalisation by macrophages. Cell Microbiol 2018; 21:e12976. [PMID: 30427108 DOI: 10.1111/cmi.12976] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 09/03/2018] [Accepted: 09/17/2018] [Indexed: 12/17/2022]
Abstract
Recognition and internalisation of intracellular pathogens by host cells is a multifactorial process, involving both stable and transient interactions. The plasticity of the host cell plasma membrane is fundamental in this infectious process. Here, the participation of macrophage lipid microdomains during adhesion and internalisation of the fungal pathogen Histoplasma capsulatum (Hc) was investigated. An increase in membrane lateral organisation, which is a characteristic of lipid microdomains, was observed during the first steps of Hc-macrophage interaction. Cholesterol enrichment in macrophage membranes around Hc contact regions and reduced levels of Hc-macrophage association after cholesterol removal also suggested the participation of lipid microdomains during Hc-macrophage interaction. Using optical tweezers to study cell-to-cell interactions, we showed that cholesterol depletion increased the time required for Hc adhesion. Additionally, fungal internalisation was significantly reduced under these conditions. Moreover, macrophages treated with the ceramide-glucosyltransferase inhibitor (P4r) and macrophages with altered ganglioside synthesis (from B4galnt1-/- mice) showed a deficient ability to interact with Hc. Coincubation of oligo-GM1 and treatment with Cholera toxin Subunit B, which recognises the ganglioside GM1, also reduced Hc association. Although purified GM1 did not alter Hc binding, treatment with P4 significantly increased the time required for Hc binding to macrophages. The content of CD18 was displaced from lipid microdomains in B4galnt1-/- macrophages. In addition, macrophages with reduced CD18 expression (CD18low ) were associated with Hc at levels similar to wild-type cells. Finally, CD11b and CD18 colocalised with GM1 during Hc-macrophage interaction. Our results indicate that lipid rafts and particularly complex gangliosides that reside in lipid rafts stabilise Hc-macrophage adhesion and mediate efficient internalisation during histoplasmosis.
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Affiliation(s)
- Allan J Guimarães
- Department of Microbiology and Parasitology, Biomedical Institute, Fluminense Federal University, Rio de Janeiro, Brazil.,Departments of Medicine (Division of Infectious Diseases) and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York
| | - Mariana Duarte de Cerqueira
- Department of General Microbiology, Microbiology Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Daniel Zamith-Miranda
- Department of General Microbiology, Microbiology Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Pablo H Lopez
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Marcio L Rodrigues
- Department of General Microbiology, Microbiology Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto Carlos Chagas, Fundação Oswaldo Cruz (Fiocruz), Curitiba, Brazil
| | - Bruno Pontes
- LPO-COPEA, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nathan B Viana
- LPO-COPEA, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,LPO-COPEA, Institute of Physics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Carlos M DeLeon-Rodriguez
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Diego Conrado Pereira Rossi
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Andre M O Gomes
- Program of Structural Biology, Institute of Medical Biochemistry Leopoldo de Meis and National Institute of Science and Technology of Structural Biology and Bioimaging, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luis R Martinez
- Biological Sciences, The University of Texas at El Paso, El Paso, Texas
| | - Ronald L Schnaar
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Joshua D Nosanchuk
- Departments of Medicine (Division of Infectious Diseases) and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York
| | - Leonardo Nimrichter
- Department of General Microbiology, Microbiology Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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10
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Serum-Mediated Cleavage of Bacillus anthracis Protective Antigen Is a Two-Step Process That Involves a Serum Carboxypeptidase. mSphere 2018; 3:3/3/e00091-18. [PMID: 29950379 PMCID: PMC6021598 DOI: 10.1128/msphere.00091-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 06/09/2018] [Indexed: 11/20/2022] Open
Abstract
Our findings identify a serum-mediated modification of PA20 that has not been previously described. These observations further imply that the processing of PA is more complex than currently thought. Additional study is needed to define the contribution of serum processing of PA to the host response and individual susceptibility to anthrax. Much of our understanding of the activity of anthrax toxin is based on in vitro systems, which delineate the interaction between Bacillus anthracis toxins and the cell surface. However, these systems fail to account for the intimate association of B. anthracis with the circulatory system, including the contribution of serum proteins to the host response and processing of anthrax toxins. Using a variety of immunological techniques to inhibit serum processing of B. anthracis protective antigen (PA) along with mass spectrometry analysis, we demonstrate that serum digests PA via 2 distinct reactions. In the first reaction, serum cleaves PA83 into 2 fragments to produce PA63 and PA20 fragments, similarly to that observed following furin digestion. This is followed by carboxypeptidase-mediated removal of the carboxy-terminal arginine and lysines from PA20. IMPORTANCE Our findings identify a serum-mediated modification of PA20 that has not been previously described. These observations further imply that the processing of PA is more complex than currently thought. Additional study is needed to define the contribution of serum processing of PA to the host response and individual susceptibility to anthrax.
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11
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Yang LL, Wu JB, Liu ZG, Liu L, Zeng MS, Yan SS, Chan HC, Xia YF. Preparation of anti-NYD-SP8 rabbit polyclonal antibody and its application in the analysis of NYD-SP8 expression in nasopharyngeal carcinoma cell lines and clinical tissues. TUMORI JOURNAL 2018; 97:655-9. [DOI: 10.1177/030089161109700519] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Aims and background NYD-SP8 is a recently identified protein, the biological characteristics of which are still unclear. The aim of this study was to prepare an anti-NYD-SP8 rabbit polyclonal antibody and investigate the expression of NYD-SP8 in human nasopharyngeal carcinoma cell lines and nasopharyngeal carcinoma tissues. Methods The anti-NYD-SP8 rabbit polyclonal antibody was prepared and ELISA was performed to assess the antibody titer. With this antibody, the NYD-SP8 expression in four nasopharyngeal carcinoma cell lines, CNE1, CNE2, 5–8F and 6–10B, was examined by Western blot and its expression in clinical tissues was also assessed by immunohistochemistry. Results The anti-NYD-SP8 rabbit polyclonal antibody with a high titer was successfully prepared. Western blot showed higher NYD-SP8 expression in CNE2 and 6–10B cells and lower expression in CNE1 and 5–8F cells. Immunohistochemistry demonstrated overexpression of NYD-SP8 in nasopharyngeal carcinoma tissue while the expression in normal nasopharyngeal tissue was negligible. Conclusions Our anti-NYD-SP8 rabbit polyclonal antibody can be used both for Western blot and immunohistochemistry, and can be a valuable tool to investigate the function and distribution of NYD-SP8. The different NYD-SP8 expression in various nasopharyngeal carcinoma cell lines indicated its complicated functions at different biological stages. The overexpression of NYD-SP8 in clinical nasopharyngeal carcinoma tissue indicated that it could play an important role in nasopharyngeal carcinoma carcinogenesis.
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Affiliation(s)
- Ling-Lin Yang
- State Key Laboratory of Oncology in South China, Guangzhou, Guangdong
- Affiliated Hospital of Luzhou Medical College, Luzhou, Sichuan
| | - Jing-Bo Wu
- Affiliated Hospital of Luzhou Medical College, Luzhou, Sichuan
| | - Zhi-Gang Liu
- State Key Laboratory of Oncology in South China, Guangzhou, Guangdong
| | - Li Liu
- State Key Laboratory of Oncology in South China, Guangzhou, Guangdong
| | - Mu-Sheng Zeng
- State Key Laboratory of Oncology in South China, Guangzhou, Guangdong
| | - Shan-Shan Yan
- State Key Laboratory of Oncology in South China, Guangzhou, Guangdong
| | - Hsiao-Chang Chan
- Epithelial Cell Biology Research Center, Li Ka Shing Institute of Health Sciences, Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Yun-Fei Xia
- State Key Laboratory of Oncology in South China, Guangzhou, Guangdong
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12
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Alves GG, Machado-de-Ávila RA, Chávez-Olórtegui CD, Silva ROS, Lobato FCF. Mapping of the continuous epitopes displayed on the Clostridium perfringens type D epsilon-toxin. Braz J Microbiol 2017; 48:570-575. [PMID: 28223027 PMCID: PMC5498415 DOI: 10.1016/j.bjm.2016.10.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 06/01/2016] [Accepted: 10/17/2016] [Indexed: 11/24/2022] Open
Abstract
The epsilon toxin, produced by Clostridium perfringens, is responsible for enterotoxemia in ruminants and is a potential bioterrorism agent. In the present study, 15 regions of the toxin were recognized by antibodies present in the serum, with different immunodominance scales, and may be antigen determinants that can be used to formulate subunit vaccines.
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Affiliation(s)
- Guilherme Guerra Alves
- Universidade Federal de Minas Gerais (UFMG), Escola de Veterinária, Belo Horizonte, MG, Brazil.
| | - Ricardo Andrez Machado-de-Ávila
- Universidade Federal de Minas Gerais (UFMG), Instituto de Ciências Biológicas, Belo Horizonte, MG, Brazil; Universidade do Extremo Sul Catarinense (UNESC), Criciúma, SC, Brazil
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13
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Letarov AV, Biryukova YK, Epremyan AS, Shevelev AB. Prospects of the use of bacteriophage-based virus-like particles in the creation of anthrax vaccines. APPL BIOCHEM MICRO+ 2017. [DOI: 10.1134/s0003683816090040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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McComb RC, Martchenko M. Neutralizing antibody and functional mapping of Bacillus anthracis protective antigen-The first step toward a rationally designed anthrax vaccine. Vaccine 2015; 34:13-9. [PMID: 26611201 DOI: 10.1016/j.vaccine.2015.11.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 10/05/2015] [Accepted: 11/09/2015] [Indexed: 12/14/2022]
Abstract
Anthrax is defined by the Centers for Disease Control and Prevention as a Category A pathogen for its potential use as a bioweapon. Current prevention treatments include Anthrax Vaccine Adsorbed (AVA). AVA is an undefined formulation of Bacillus anthracis culture supernatant adsorbed to aluminum hydroxide. It has an onerous vaccination schedule, is slow and cumbersome to produce and is slightly reactogenic. Next-generation vaccines are focused on producing recombinant forms of anthrax toxin in a well-defined formulation but these vaccines have been shown to lose potency as they are stored. In addition, studies have shown that a proportion of the antibody response against these vaccines is focused on non-functional, non-neutralizing regions of the anthrax toxin while some essential functional regions are shielded from eliciting an antibody response. Rational vaccinology is a developing field that focuses on designing vaccine antigens based on structural information provided by neutralizing antibody epitope mapping, crystal structure analysis, and functional mapping through amino acid mutations. This information provides an opportunity to design antigens that target only functionally important and conserved regions of a pathogen in order to make a more optimal vaccine product. This review provides an overview of the literature related to functional and neutralizing antibody epitope mapping of the Protective Antigen (PA) component of anthrax toxin.
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Affiliation(s)
- Ryan C McComb
- Keck Graduate Institute, School of Applied Life Science, 535 Watson Dr., Claremont, CA, United States
| | - Mikhail Martchenko
- Keck Graduate Institute, School of Applied Life Science, 535 Watson Dr., Claremont, CA, United States.
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15
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Evaluation of anthrax vaccine safety in 18 to 20 year olds: A first step towards age de-escalation studies in adolescents. Vaccine 2015; 33:2470-6. [DOI: 10.1016/j.vaccine.2015.03.071] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 03/02/2015] [Accepted: 03/24/2015] [Indexed: 11/18/2022]
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16
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Preparation and evaluation of human-murine chimeric antibody against protective antigen of Bacillus anthracis. Int J Mol Sci 2014; 15:18496-507. [PMID: 25318053 PMCID: PMC4227228 DOI: 10.3390/ijms151018496] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 09/25/2014] [Accepted: 09/30/2014] [Indexed: 12/24/2022] Open
Abstract
The aim of this research is to develop a human/murine chimeric Fab antibody which neutralizes the anthrax toxin, protective antigen (PA). The chimeric Fab was constructed using variable regions of murine anti-PA monoclonal antibody in combination with constant regions of human IgG. The chimeric PA6-Fab was expressed in E. coli. BL21 and evaluated by ELISA and co-immunoprecipitation- mass spectra. The potency of PA6-Fab to neutralize LeTx was examined in J774A.1 cell viability in vitro and in Fisher 344 rats in vivo. The PA6-Fab did not have domain similarity corresponding to the current anti PA mAbs, but specifically bound to anthrax PA at an affinity of 1.76 nM, and was able to neutralize LeTx in vitro and protected 56.9% cells at 20 μg/mL against anthrax LeTx. One hundred μg PA6-Fab could neutralize 300 μg LeTx in vivo. The PA6-Fab has potential as a therapeutic mAb for treatment of anthrax.
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17
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Whiting G, Wheeler JX, Rijpkema S. Identification of peptide sequences as a measure of Anthrax vaccine stability during storage. Hum Vaccin Immunother 2014; 10:1669-81. [PMID: 24637775 PMCID: PMC4185962 DOI: 10.4161/hv.28443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The UK anthrax vaccine is an alum precipitate of a sterile filtrate of Bacillus anthracis Sterne culture (AVP). An increase in shelf life of AVP from 3 to 5 years prompted us to investigate the in vivo potency and the antigen content of 12 batches with a shelf life of 6.4 to 9.9 years and one bulk with a shelf life of 23.8 years. All batches, except for a 9.4-year-old batch, passed the potency test. Mass spectrometry (MS) and in-gel difference 2-dimensional gel electrophoresis (DIGE) were used to examine antigens of the pellet and supernatant of AVP. The pellet contained proteins with a MW in excess of 15 kDa. DIGE of desorbed proteins from the pellet revealed that with aging, 19 spots showed a significant change in size or intensity, a sign of protein degradation. MS identified 21 proteins including protective antigen (PA), enolase, lethal factor (LF), nucleoside diphosphate kinase, edema factor, and S-layer proteins. Fifteen proteins were detected for the first time including metabolic enzymes, iron binding proteins, and manganese dependent superoxide dismutase (MnSOD). The supernatant contained131 peptide sequences. Peptides representing septum formation inhibitor protein and repeat domain protein were most abundant. Five proteins were shared with the pellet: 2,3,4,5-tetrahydropyridine-6-dicarboxylate N-succinyltransferase, enolase, LF, MnSOD, and PA. The number of peptide sequences increased with age. Peptides from PA and LF appeared once batches exceeded their shelf life by 2 and 4 years, respectively. In conclusion, changes in antigen content resulting from decay or desorption only had a limited effect on in vivo potency of AVP. The presence of PA and LF peptides in the supernatant can inform on the age and stability of AVP.
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Affiliation(s)
- Gail Whiting
- Division of Bacteriology; National Institute for Biological Standards and Control; Hertfordshire, UK
| | - Jun X Wheeler
- Laboratory of Molecular Structure; National Institute for Biological Standards and Control; Hertfordshire, UK
| | - Sjoerd Rijpkema
- Division of Bacteriology; National Institute for Biological Standards and Control; Hertfordshire, UK
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18
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Chow SK, Smith C, MacCarthy T, Pohl MA, Bergman A, Casadevall A. Disease-enhancing antibodies improve the efficacy of bacterial toxin-neutralizing antibodies. Cell Host Microbe 2014; 13:417-28. [PMID: 23601104 DOI: 10.1016/j.chom.2013.03.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 01/14/2013] [Accepted: 02/13/2013] [Indexed: 12/25/2022]
Abstract
During infection, humoral immunity produces a polyclonal response with various immunoglobulins recognizing different epitopes within the microbe or toxin. Despite this diverse response, the biological activity of an antibody (Ab) is usually assessed by the action of a monoclonal population. We demonstrate that a combination of monoclonal antibodies (mAbs) that are individually disease enhancing or neutralizing to Bacillus anthracis protective antigen (PA), a component of anthrax toxin, results in significantly augmented protection against the toxin. This boosted protection is Fc gamma receptor (FcγR) dependent and involves the formation of stoichiometrically defined mAb-PA complexes that requires immunoglobulin bivalence and simultaneous interaction between PA and the two mAbs. The formation of these mAb-PA complexes inhibits PA oligomerization, resulting in protection. These data suggest that functional assessments of single Abs may inaccurately predict how the same Abs will operate in polyclonal preparations and imply that potentially therapeutic mAbs may be overlooked in single Ab screens.
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Affiliation(s)
- Siu-Kei Chow
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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19
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Brojatsch J, Casadevall A, Goldman DL. Molecular determinants for a cardiovascular collapse in anthrax. Front Biosci (Elite Ed) 2014; 6:139-47. [PMID: 24389148 DOI: 10.2741/e697] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Bacillus anthracis releases two bipartite proteins, lethal toxin and edema factor, that contribute significantly to the progression of anthrax-associated shock. As blocking the anthrax toxins prevents disease, the toxins are considered the main virulence factors of the bacterium. The anthrax bacterium and the anthrax toxins trigger multi-organ failure associated with enhanced vascular permeability, hemorrhage and cardiac dysfunction in animal challenge models. A recent study using mice that either lacked the anthrax toxin receptor in specific cells and corresponding mice expressing the receptor in specific cell types demonstrated that cardiovascular cells are critical for disease mediated by anthrax lethal toxin. These studies are consistent with involvement of the cardiovascular system, and with an increase of cardiac failure markers observed in human anthrax and in animal models using B. anthracis and anthrax toxins. This review discusses the current state of knowledge regarding the pathophysiology of anthrax and tries to provide a mechanistic model and molecular determinants for the circulatory shock in anthrax.
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Affiliation(s)
- Jurgen Brojatsch
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY
| | - Arturo Casadevall
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY
| | - David L Goldman
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY
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20
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Garman L, Dumas EK, Kurella S, Hunt JJ, Crowe SR, Nguyen ML, Cox PM, James JA, Farris AD. MHC class II and non-MHC class II genes differentially influence humoral immunity to Bacillus anthracis lethal factor and protective antigen. Toxins (Basel) 2013; 4:1451-67. [PMID: 23342680 PMCID: PMC3528256 DOI: 10.3390/toxins4121451] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Anthrax Lethal Toxin consists of Protective Antigen (PA) and Lethal Factor (LF), and current vaccination strategies focus on eliciting antibodies to PA. In human vaccination, the response to PA can vary greatly, and the response is often directed toward non-neutralizing epitopes. Variable vaccine responses have been shown to be due in part to genetic differences in individuals, with both MHC class II and other genes playing roles. Here, we investigated the relative contribution of MHC class II versus non-MHC class II genes in the humoral response to PA and LF immunization using three immunized strains of inbred mice: A/J (H-2k at the MHC class II locus), B6 (H-2b), and B6.H2k (H-2k). IgG antibody titers to LF were controlled primarily by the MHC class II locus, whereas IgG titers to PA were strongly influenced by the non-MHC class II genetic background. Conversely, the humoral fine specificity of reactivity to LF appeared to be controlled primarily through non-MHC class II genes, while the specificity of reactivity to PA was more dependent on MHC class II. Common epitopes, reactive in all strains, occurred in both LF and PA responses. These results demonstrate that MHC class II differentially influences humoral immune responses to LF and PA.
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Affiliation(s)
- Lori Garman
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA; E-Mails: (L.G.); (E.K.D.); (S.K.); (S.R.C.); (M.L.N.); (P.M.C.); (J.A.J.)
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA; E-Mail:
| | - Eric K. Dumas
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA; E-Mails: (L.G.); (E.K.D.); (S.K.); (S.R.C.); (M.L.N.); (P.M.C.); (J.A.J.)
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA; E-Mail:
| | - Sridevi Kurella
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA; E-Mails: (L.G.); (E.K.D.); (S.K.); (S.R.C.); (M.L.N.); (P.M.C.); (J.A.J.)
| | - Jonathan J. Hunt
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA; E-Mail:
| | - Sherry R. Crowe
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA; E-Mails: (L.G.); (E.K.D.); (S.K.); (S.R.C.); (M.L.N.); (P.M.C.); (J.A.J.)
| | - Melissa L. Nguyen
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA; E-Mails: (L.G.); (E.K.D.); (S.K.); (S.R.C.); (M.L.N.); (P.M.C.); (J.A.J.)
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA; E-Mail:
| | - Philip M. Cox
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA; E-Mails: (L.G.); (E.K.D.); (S.K.); (S.R.C.); (M.L.N.); (P.M.C.); (J.A.J.)
| | - Judith A. James
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA; E-Mails: (L.G.); (E.K.D.); (S.K.); (S.R.C.); (M.L.N.); (P.M.C.); (J.A.J.)
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA; E-Mail:
- Departments of Medicine and Pathology, University of Oklahoma Health Sciences Center, 1000 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
| | - A. Darise Farris
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA; E-Mails: (L.G.); (E.K.D.); (S.K.); (S.R.C.); (M.L.N.); (P.M.C.); (J.A.J.)
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-405-271-7389; Fax: +1-405-271-4110
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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: 15] [Impact Index Per Article: 1.4] [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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22
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Klöhn PC, Wuellner U, Zizlsperger N, Zhou Y, Tavares D, Berger S, Zettlitz KA, Proetzel G, Yong M, Begent RH, Reichert JM. IBC's 23rd Annual Antibody Engineering, 10th Annual Antibody Therapeutics international conferences and the 2012 Annual Meeting of The Antibody Society: December 3-6, 2012, San Diego, CA. MAbs 2013; 5:178-201. [PMID: 23575266 PMCID: PMC3893229 DOI: 10.4161/mabs.23655] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 01/17/2013] [Indexed: 01/13/2023] Open
Abstract
The 23rd Annual Antibody Engineering, 10th Annual Antibody Therapeutics international conferences, and the 2012 Annual Meeting of The Antibody Society, organized by IBC Life Sciences with contributions from The Antibody Society and two Scientific Advisory Boards, were held December 3-6, 2012 in San Diego, CA. The meeting drew over 800 participants who attended sessions on a wide variety of topics relevant to antibody research and development. As a prelude to the main events, a pre-conference workshop held on December 2, 2012 focused on intellectual property issues that impact antibody engineering. The Antibody Engineering Conference was composed of six sessions held December 3-5, 2012: (1) From Receptor Biology to Therapy; (2) Antibodies in a Complex Environment; (3) Antibody Targeted CNS Therapy: Beyond the Blood Brain Barrier; (4) Deep Sequencing in B Cell Biology and Antibody Libraries; (5) Systems Medicine in the Development of Antibody Therapies/Systematic Validation of Novel Antibody Targets; and (6) Antibody Activity and Animal Models. The Antibody Therapeutics conference comprised four sessions held December 4-5, 2012: (1) Clinical and Preclinical Updates of Antibody-Drug Conjugates; (2) Multifunctional Antibodies and Antibody Combinations: Clinical Focus; (3) Development Status of Immunomodulatory Therapeutic Antibodies; and (4) Modulating the Half-Life of Antibody Therapeutics. The Antibody Society's special session on applications for recording and sharing data based on GIATE was held on December 5, 2012, and the conferences concluded with two combined sessions on December 5-6, 2012: (1) Development Status of Early Stage Therapeutic Antibodies; and (2) Immunomodulatory Antibodies for Cancer Therapy.
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Affiliation(s)
- Peter-Christian Klöhn
- MRC Prion Unit; Department of Neurodegenerative Diseases; UCL Institute of Neurology; London, UK
| | | | - Nora Zizlsperger
- Protein Engineering and Antibody Technologies; EMD Serono Research Institute, Inc.; Billerica MA USA
| | - Yu Zhou
- Department of Anesthesia; University of California, San Francisco; San Francisco, CA USA
| | | | - Sven Berger
- Institut de Recherche, Centre d'Immunologie Pierre Fabre; St Julien en Genevois, France
| | - Kirstin A. Zettlitz
- Crump Institute for Molecular Imaging; Department of Molecular and Medical Pharmacology; David Geffen School of Medicine at UCLA; California NanoSystems Institute; University of California Los Angeles; Los Angeles, CA USA
| | | | - May Yong
- UCL Cancer Institute; London, UK
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Abstract
Antibiotic treatment may fail to protect individuals, if not started early enough, after infection with Bacillus anthracis, due to the continuing activity of toxins that the bacterium produces. Stable and easily stored inhibitors of the edema factor toxin (EF), an adenylyl cyclase, could save lives in the event of an outbreak, due to natural causes or a bioweapon attack. The toxin’s basic activity is to convert ATP to cAMP, and it is thus in principle a simple phosphatase, which means that many mammalian enzymes, including intracellular adenylcyclases, may have a similar activity. While nucleotide based inhibitors, similar to its natural substrate, ATP, were identified early, these compounds had low activity and specificity for EF. We used a combined structural and computational approach to choose small organic molecules in large, web-based compound libraries that would, based on docking scores, bind to residues within the substrate binding pocket of EF. A family of fluorenone-based inhibitors was identified that inhibited the release of cAMP from cells treated with EF. The lead inhibitor was also shown to inhibit the diarrhea caused by enterotoxigenic E. coli (ETEC) in a murine model, perhaps by serving as a quorum sensor. These inhibitors are now being tested for their ability to inhibit Anthrax infection in animal models and may have use against other pathogens that produce toxins similar to EF, such as Bordetella pertussis or Vibrio cholera.
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A three-dose intramuscular injection schedule of anthrax vaccine adsorbed generates sustained humoral and cellular immune responses to protective antigen and provides long-term protection against inhalation anthrax in rhesus macaques. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2012; 19:1730-45. [PMID: 22933399 DOI: 10.1128/cvi.00324-12] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A 3-dose (0, 1, and 6 months) intramuscular (3-IM) priming series of a human dose (HuAVA) and dilutions of up to 1:10 of anthrax vaccine adsorbed (AVA) provided statistically significant levels of protection (60 to 100%) against inhalation anthrax for up to 4 years in rhesus macaques. Serum anti-protective antigen (anti-PA) IgG and lethal toxin neutralization activity (TNA) were detectable following a single injection of HuAVA or 1:5 AVA or following two injections of diluted vaccine (1:10, 1:20, or 1:40 AVA). Anti-PA and TNA were highly correlated (overall r(2) = 0.89 for log(10)-transformed data). Peak responses were seen at 6.5 months. In general, with the exception of animals receiving 1:40 AVA, serum anti-PA and TNA responses remained significantly above control levels at 28.5 months (the last time point measured for 1:20 AVA), and through 50.5 months for the HuAVA and 1:5 and 1:10 AVA groups (P < 0.05). PA-specific gamma interferon (IFN-γ) and interleukin-4 (IL-4) CD4(+) cell frequencies and T cell stimulation indices were sustained through 50.5 months (the last time point measured). PA-specific memory B cell frequencies were highly variable but, in general, were detectable in peripheral blood mononuclear cells (PBMC) by 2 months, were significantly above control levels by 7 months, and remained detectable in the HuAVA and 1:5 and 1:20 AVA groups through 42 months (the last time point measured). HuAVA and diluted AVA elicited a combined Th1/Th2 response and robust immunological priming, with sustained production of high-avidity PA-specific functional antibody, long-term immune cell competence, and immunological memory (30 months for 1:20 AVA and 52 months for 1:10 AVA). Vaccinated animals surviving inhalation anthrax developed high-magnitude anamnestic anti-PA IgG and TNA responses.
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Chow SK, Casadevall A. Monoclonal antibodies and toxins--a perspective on function and isotype. Toxins (Basel) 2012; 4:430-54. [PMID: 22822456 PMCID: PMC3398419 DOI: 10.3390/toxins4060430] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Revised: 06/06/2012] [Accepted: 06/07/2012] [Indexed: 11/16/2022] Open
Abstract
Antibody therapy remains the only effective treatment for toxin-mediated diseases. The development of hybridoma technology has allowed the isolation of monoclonal antibodies (mAbs) with high specificity and defined properties, and numerous mAbs have been purified and characterized for their protective efficacy against different toxins. This review summarizes the mAb studies for 6 toxins—Shiga toxin, pertussis toxin, anthrax toxin, ricin toxin, botulinum toxin, and Staphylococcal enterotoxin B (SEB)—and analyzes the prevalence of mAb functions and their isotypes. Here we show that most toxin-binding mAbs resulted from immunization are non-protective and that mAbs with potential therapeutic use are preferably characterized. Various common practices and caveats of protection studies are discussed, with the goal of providing insights for the design of future research on antibody-toxin interactions.
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Affiliation(s)
- Siu-Kei Chow
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA;
| | - Arturo Casadevall
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA;
- Division of Infectious Diseases of the Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA
- Author to whom correspondence should be addressed; ; Tel.: +1-718-430-2811; Fax: +1-718-430-8711
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O'Hara JM, Yermakova A, Mantis NJ. Immunity to ricin: fundamental insights into toxin-antibody interactions. Curr Top Microbiol Immunol 2012; 357:209-41. [PMID: 22113742 PMCID: PMC4433546 DOI: 10.1007/82_2011_193] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ricin toxin is an extraordinarily potent inducer of cell death and inflammation. Ricin is also a potent provocateur of the humoral immune system, eliciting a mixture of neutralizing, non-neutralizing and even toxin-enhancing antibodies. The characterization of dozens of monoclonal antibodies (mAbs) against the toxin's enzymatic (RTA) and binding (RTB) subunits has begun to reveal fundamental insights into the underlying mechanisms by which antibodies neutralize (or fail to neutralize) ricin in systemic and mucosal compartments. This information has had immediate applications in the design, development and evaluation of ricin subunit vaccines and immunotherapeutics.
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Affiliation(s)
- Joanne M. O'Hara
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, NY 12208, USA; Department of Biomedical Sciences, University at Albany School of Public Health, Albany, NY 12201, USA
| | - Anastasiya Yermakova
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, NY 12208, USA; Department of Biomedical Sciences, University at Albany School of Public Health, Albany, NY 12201, USA
| | - Nicholas J. Mantis
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, NY 12208, USA; Department of Biomedical Sciences, University at Albany School of Public Health, Albany, NY 12201, USA
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Bacillus anthracis produces membrane-derived vesicles containing biologically active toxins. Proc Natl Acad Sci U S A 2010. [PMID: 20956325 DOI: 10.1073/pnas.1008843107.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Extracellular vesicle production is a ubiquitous process in Gram-negative bacteria, but little is known about such process in Gram-positive bacteria. We report the isolation of extracellular vesicles from the supernatants of Bacillus anthracis, a Gram-positive bacillus that is a powerful agent for biological warfare. B. anthracis vesicles formed at the outer layer of the bacterial cell had double-membrane spheres and ranged from 50 to 150 nm in diameter. Immunoelectron microscopy with mAbs to protective antigen, lethal factor, edema toxin, and anthrolysin revealed toxin components and anthrolysin in vesicles, with some vesicles containing more than one toxin component. Toxin-containing vesicles were also visualized inside B. anthracis-infected macrophages. ELISA and immunoblot analysis of vesicle preparations confirmed the presence of B. anthracis toxin components. A mAb to protective antigen protected macrophages against vesicles from an anthrolysin-deficient strain, but not against vesicles from Sterne 34F2 and Sterne δT strains, consistent with the notion that vesicles delivered both toxin and anthrolysin to host cells. Vesicles were immunogenic in BALB/c mice, which produced a robust IgM response to toxin components. Furthermore, vesicle-immunized mice lived significantly longer than controls after B. anthracis challenge. Our results indicate that toxin secretion in B. anthracis is, at least, partially vesicle-associated, thus allowing concentrated delivery of toxin components to target host cells, a mechanism that may increase toxin potency. Our observations may have important implications for the design of vaccines, for passive antibody strategies, and provide a previously unexplored system for studying secretory pathways in Gram-positive bacteria.
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Bacillus anthracis produces membrane-derived vesicles containing biologically active toxins. Proc Natl Acad Sci U S A 2010; 107:19002-7. [PMID: 20956325 DOI: 10.1073/pnas.1008843107] [Citation(s) in RCA: 274] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Extracellular vesicle production is a ubiquitous process in Gram-negative bacteria, but little is known about such process in Gram-positive bacteria. We report the isolation of extracellular vesicles from the supernatants of Bacillus anthracis, a Gram-positive bacillus that is a powerful agent for biological warfare. B. anthracis vesicles formed at the outer layer of the bacterial cell had double-membrane spheres and ranged from 50 to 150 nm in diameter. Immunoelectron microscopy with mAbs to protective antigen, lethal factor, edema toxin, and anthrolysin revealed toxin components and anthrolysin in vesicles, with some vesicles containing more than one toxin component. Toxin-containing vesicles were also visualized inside B. anthracis-infected macrophages. ELISA and immunoblot analysis of vesicle preparations confirmed the presence of B. anthracis toxin components. A mAb to protective antigen protected macrophages against vesicles from an anthrolysin-deficient strain, but not against vesicles from Sterne 34F2 and Sterne δT strains, consistent with the notion that vesicles delivered both toxin and anthrolysin to host cells. Vesicles were immunogenic in BALB/c mice, which produced a robust IgM response to toxin components. Furthermore, vesicle-immunized mice lived significantly longer than controls after B. anthracis challenge. Our results indicate that toxin secretion in B. anthracis is, at least, partially vesicle-associated, thus allowing concentrated delivery of toxin components to target host cells, a mechanism that may increase toxin potency. Our observations may have important implications for the design of vaccines, for passive antibody strategies, and provide a previously unexplored system for studying secretory pathways in Gram-positive bacteria.
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Abboud N, Chow SK, Saylor C, Janda A, Ravetch JV, Scharff MD, Casadevall A. A requirement for FcγR in antibody-mediated bacterial toxin neutralization. ACTA ACUST UNITED AC 2010; 207:2395-405. [PMID: 20921285 PMCID: PMC2964574 DOI: 10.1084/jem.20100995] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Constant regions of antibodies influence toxin neutralization in a manner dependent on FcγR. One important function of humoral immunity is toxin neutralization. The current view posits that neutralization results from antibody-mediated interference with the binding of toxins to their targets, a phenomenon viewed as dependent only on antibody specificity. To investigate the role of antibody constant region function in toxin neutralization, we generated IgG2a and IgG2b variants of the Bacillus anthracis protective antigen–binding IgG1 monoclonal antibody (mAb) 19D9. These antibodies express identical variable regions and display the same specificity. The efficacy of antibody-mediated neutralization was IgG2a > IgG2b > IgG1, and neutralization activity required competent Fcγ receptor (FcγR). The IgG2a mAb prevented lethal toxin cell killing and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase cleavage more efficiently than the IgG1 mAb. Passive immunization with IgG1 and IgG2a mAb protected wild-type mice, but not FcγR-deficient mice, against B. anthracis infection. These results establish that constant region isotype influences toxin neutralization efficacy of certain antibodies through a mechanism that requires engagement of FcγR. These findings highlight a new parameter for evaluating vaccine responses and the possibility of harnessing optimal FcγR interactions in the design of passive immunization strategies.
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Affiliation(s)
- Nareen Abboud
- Department of Microbiology and Immunology, Division of Infectious Diseases, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Sedegah M, Kim Y, Peters B, McGrath S, Ganeshan H, Lejano J, Abot E, Banania G, Belmonte M, Sayo R, Farooq F, Doolan DL, Regis D, Tamminga C, Chuang I, Bruder JT, King CR, Ockenhouse CF, Faber B, Remarque E, Hollingdale MR, Richie TL, Sette A. Identification and localization of minimal MHC-restricted CD8+ T cell epitopes within the Plasmodium falciparum AMA1 protein. Malar J 2010; 9:241. [PMID: 20735847 PMCID: PMC2939619 DOI: 10.1186/1475-2875-9-241] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 08/24/2010] [Indexed: 12/14/2022] Open
Abstract
Background Plasmodium falciparum apical membrane antigen-1 (AMA1) is a leading malaria vaccine candidate antigen that is expressed by sporozoite, liver and blood stage parasites. Since CD8+ T cell responses have been implicated in protection against pre-erythrocytic stage malaria, this study was designed to identify MHC class I-restricted epitopes within AMA1. Methods A recombinant adenovirus serotype 5 vector expressing P. falciparum AMA1 was highly immunogenic when administered to healthy, malaria-naive adult volunteers as determined by IFN-γ ELISpot responses to peptide pools containing overlapping 15-mer peptides spanning full-length AMA1. Computerized algorithms (NetMHC software) were used to predict minimal MHC-restricted 8-10-mer epitope sequences within AMA1 15-mer peptides active in ELISpot. A subset of epitopes was synthesized and tested for induction of CD8+ T cell IFN-γ responses by ELISpot depletion and ICS assays. A 3-dimensional model combining Domains I + II of P. falciparum AMA1 and Domain III of P. vivax AMA1 was used to map these epitopes. Results Fourteen 8-10-mer epitopes were predicted to bind to HLA supertypes A01 (3 epitopes), A02 (4 epitopes), B08 (2 epitopes) and B44 (5 epitopes). Nine of the 14 predicted epitopes were recognized in ELISpot or ELISpot and ICS assays by one or more volunteers. Depletion of T cell subsets confirmed that these epitopes were CD8+ T cell-dependent. A mixture of the 14 minimal epitopes was capable of recalling CD8+ T cell IFN-γ responses from PBMC of immunized volunteers. Thirteen of the 14 predicted epitopes were polymorphic and the majority localized to the more conserved front surface of the AMA1 model structure. Conclusions This study predicted 14 and confirmed nine MHC class I-restricted CD8+ T cell epitopes on AMA1 recognized in the context of seven HLA alleles. These HLA alleles belong to four HLA supertypes that have a phenotypic frequency between 23% - 100% in different human populations.
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Affiliation(s)
- Martha Sedegah
- USMMVP, Malaria Department, NMRC, Silver Spring, MD 20910, USA
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Oscherwitz J, Yu F, Cease KB. A synthetic peptide vaccine directed against the 2ß2-2ß3 loop of domain 2 of protective antigen protects rabbits from inhalation anthrax. THE JOURNAL OF IMMUNOLOGY 2010; 185:3661-8. [PMID: 20696862 DOI: 10.4049/jimmunol.1001749] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The current vaccines for anthrax in the United States and United Kingdom are efficacious in the two most accepted animal models of inhalation anthrax, nonhuman primates and rabbits, but require extensive immunization protocols. We previously demonstrated that a linear determinant in domain 2 of Bacillus anthracis protective Ag (PA) is a potentially important target for an epitope-specific vaccine for anthrax, as Abs specific for this site, referred to as the loop-neutralizing determinant (LND), neutralize lethal toxin in vitro, yet are virtually absent in PA-immunized rabbits. In this study, we evaluated the immunogenicity and protective efficacy in rabbits of multiple antigenic peptides (MAPs) consisting of aa 304-319 from the LND of PA colinearly synthesized at the C terminus (T-B MAP) or N terminus (B-T MAP) with a heterologous T cell epitope from Plasmodium falciparum. Immunogenicity studies demonstrated that both MAPs elicited toxin-neutralizing Ab in rabbits. To evaluate the MAPs as potential anthrax vaccines, we immunized groups of rabbits (n = 7) with each MAP in Freund's adjuvant and then exposed all rabbits to a 200-LD(50) challenge with aerosolized spores of B. anthracis Ames strain. All seven rabbits immunized with the B-T MAP and 89% (six of seven) of rabbits immunized with the T-B MAP survived the spore challenge. Corollary studies with reference sera from human vaccinees immunized with rPA or anthrax vaccine absorbed and nonhuman primates immunized with PA revealed no detectable Ab with specificity for the LND. We conclude that a synthetic peptide vaccine targeting the LND would be a potentially efficacious vaccine for anthrax.
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Affiliation(s)
- Jon Oscherwitz
- Division of Hematology-Oncology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48105, USA.
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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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Induction of neutralizing antibody responses to anthrax protective antigen by using influenza virus vectors: implications for disparate immune system priming pathways. J Virol 2010; 84:8300-7. [PMID: 20504926 DOI: 10.1128/jvi.00183-10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Viral vectors based on influenza virus, rabies virus (RV), and vaccinia virus (VV) were used to express large polypeptide segments derived from the Bacillus anthracis protective antigen (PA). For the infectious influenza virus vector and recombinant VV constructs, the receptor binding domain (RBD or domain 4) or the lethal and edema factor binding domain (LEF or domain 1') were engineered into functional chimeric hemagglutinin (HA) glycoproteins. In the case of the RV vector, the viral glycoprotein (G) was used as a carrier for RBD in an inactivated form of the vector. These constructs were examined by using multiple homologous and heterologous prime/boost immunization regimens in order to optimize the induction of alpha-PA antibody responses. Several immunization combinations were shown to induce high titers of antibody recognizing the anthrax RBD and LEF domains, as well as the full-length PA protein in mice. The heterologous prime/boost immunization regimens that involved an initial intranasal administration of a live influenza virus vector, followed by an intramuscular boost with either the killed RV vector or the VV vector, were particularly effective, inducing antigen-specific antibodies at levels severalfold higher than homologous or alternative heterologous protocols. Furthermore, sera from several groups of the immunized mice demonstrated neutralization activity in an in vitro anthrax toxin neutralization assay. In some cases, such toxin-neutralizing activity was notably high, indicating that the mechanisms by which immunity is primed by live influenza virus vectors may have beneficial properties.
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Radiolabeled antibodies to Bacillus anthracis toxins are bactericidal and partially therapeutic in experimental murine anthrax. Antimicrob Agents Chemother 2009; 53:4860-8. [PMID: 19704133 DOI: 10.1128/aac.01269-08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus anthracis is a powerful agent for use in biological warfare, and infection with the organism is associated with a high rate of mortality, underscoring the need for additional effective therapies for anthrax. Radioimmunotherapy (RIT) takes advantage of the specificity and affinity of the antigen-antibody interaction to deliver a microbicidal radioactive nuclide to a site of infection. RIT has proven therapeutic in experimental models of viral, bacterial, and fungal infections; but it is not known whether this approach can successfully employ toxin binding monoclonal antibodies (MAbs) for diseases caused by toxigenic bacteria. Indirect immunofluorescence studies with MAbs to protective antigen (MAbs 7.5G gamma2b and 10F4 gamma1) and lethal factor (MAb 14FA gamma2b) revealed the surface expression of toxins on bacterial cells. Scatchard analysis of MAbs revealed high binding constants and numerous binding sites on the bacterial surface. To investigate the microbicidal properties of these MAbs, our group radiolabeled MAbs with either (188)Re or (213)Bi. In vitro, (213)Bi was more efficient than (188)Re in mediating microbicidal activity against B. anthracis. The administration of MAbs [(213)Bi]10F4 gamma1 and [(213)Bi]14FA gamma2b prolonged the survival of A/JCr mice infected with B. anthracis Sterne bacterial cells but not B. anthracis Sterne spores. These results indicate that RIT with MAbs that target B. anthracis toxin components can be used to treat experimental anthrax infection and suggest that toxigenic bacteria may be targeted with radiolabeled MAbs.
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