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Chen Z, Zhang P, Matsuoka Y, Tsybovsky Y, West K, Santos C, Boyd LF, Nguyen H, Pomerenke A, Stephens T, Olia AS, Zhang B, De Giorgi V, Holbrook MR, Gross R, Postnikova E, Garza NL, Johnson RF, Margulies DH, Kwong PD, Alter HJ, Buchholz UJ, Lusso P, Farci P. Potent monoclonal antibodies neutralize Omicron sublineages and other SARS-CoV-2 variants. Cell Rep 2022; 41:111528. [PMID: 36302375 PMCID: PMC9554601 DOI: 10.1016/j.celrep.2022.111528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 07/29/2022] [Accepted: 09/28/2022] [Indexed: 11/17/2022] Open
Abstract
The emergence and global spread of the SARS-CoV-2 Omicron variants, which carry an unprecedented number of mutations, raise serious concerns due to the reduced efficacy of current vaccines and resistance to therapeutic antibodies. Here, we report the generation and characterization of two potent human monoclonal antibodies, NA8 and NE12, against the receptor-binding domain of the SARS-CoV-2 spike protein. NA8 interacts with a highly conserved region and has a breadth of neutralization with picomolar potency against the Beta variant and the Omicron BA.1 and BA.2 sublineages and nanomolar potency against BA.2.12.1 and BA.4. Combination of NA8 and NE12 retains potent neutralizing activity against the major SARS-CoV-2 variants of concern. Cryo-EM analysis provides the structural basis for the broad and complementary neutralizing activity of these two antibodies. We confirm the in vivo protective and therapeutic efficacies of NA8 and NE12 in the hamster model. These results show that broad and potent human antibodies can overcome the continuous immune escape of evolving SARS-CoV-2 variants.
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Affiliation(s)
- Zhaochun Chen
- Hepatic Pathogenesis Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
| | - Peng Zhang
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Yumiko Matsuoka
- RNA Viruses Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Yaroslav Tsybovsky
- Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Kamille West
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Celia Santos
- RNA Viruses Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Lisa F Boyd
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Hanh Nguyen
- Hepatic Pathogenesis Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Anna Pomerenke
- Hepatic Pathogenesis Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Tyler Stephens
- Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Adam S Olia
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Baoshan Zhang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Valeria De Giorgi
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Michael R Holbrook
- National Institute of Allergy and Infectious Diseases (NIAID) Integrated Research Facility, National Institutes of Health, Frederick, MD, USA
| | - Robin Gross
- National Institute of Allergy and Infectious Diseases (NIAID) Integrated Research Facility, National Institutes of Health, Frederick, MD, USA
| | - Elena Postnikova
- National Institute of Allergy and Infectious Diseases (NIAID) Integrated Research Facility, National Institutes of Health, Frederick, MD, USA
| | - Nicole L Garza
- SARS-CoV-2 Virology Core, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Reed F Johnson
- SARS-CoV-2 Virology Core, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - David H Margulies
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Harvey J Alter
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Ursula J Buchholz
- RNA Viruses Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Paolo Lusso
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Patrizia Farci
- Hepatic Pathogenesis Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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Avril A, Tournier JN, Paucod JC, Fournes B, Thullier P, Pelat T. Antibodies against Anthrax Toxins: A Long Way from Benchlab to the Bedside. Toxins (Basel) 2022; 14:toxins14030172. [PMID: 35324669 PMCID: PMC8955606 DOI: 10.3390/toxins14030172] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 02/01/2023] Open
Abstract
Anthrax is an acute disease caused by the bacterium Bacillus anthracis, and is a potential biowarfare/bioterrorist agent. Its pulmonary form, caused by inhalation of the spores, is highly lethal and is mainly related to injury caused by the toxins secretion. Antibodies neutralizing the toxins of B. anthracis are regarded as promising therapeutic drugs, and two are already approved by the Federal Drug Administration. We developed a recombinant human-like humanized antibody, 35PA83 6.20, that binds the protective antigen and that neutralized anthrax toxins in-vivo in White New Zealand rabbits infected with the lethal 9602 strain by intranasal route. Considering these promising results, the preclinical and clinical phase one development was funded and a program was started. Unfortunately, after 5 years, the preclinical development was cancelled due to industrial and scientific issues. This shutdown underlined the difficulty particularly, but not only, for an academic laboratory to proceed to clinical development, despite the drug candidate being promising. Here, we review our strategy and some preliminary results, and we discuss the issues that led to the no-go decision of the pre-clinical development of 35PA83 6.20 mAb. Our review provides general information to the laboratories planning a (pre-)clinical development.
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Affiliation(s)
- Arnaud Avril
- Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France; (J.-N.T.); (J.-C.P.); (P.T.); (T.P.)
- Correspondence: ; Tel.: +33-(0)-1-78-65-10-72
| | - Jean-Nicolas Tournier
- Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France; (J.-N.T.); (J.-C.P.); (P.T.); (T.P.)
- Ecole du Val-de-Grâce, 75005 Paris, France
| | - Jean-Charles Paucod
- Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France; (J.-N.T.); (J.-C.P.); (P.T.); (T.P.)
| | - Bénédicte Fournes
- Laboratoire Français du Fractionnement et des Biotechnologies, 91940 Les Ulis, France;
| | - Philippe Thullier
- Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France; (J.-N.T.); (J.-C.P.); (P.T.); (T.P.)
| | - Thibaut Pelat
- Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France; (J.-N.T.); (J.-C.P.); (P.T.); (T.P.)
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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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On the Use of Surface Plasmon Resonance Biosensing to Understand IgG-FcγR Interactions. Int J Mol Sci 2021; 22:ijms22126616. [PMID: 34205578 PMCID: PMC8235063 DOI: 10.3390/ijms22126616] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 01/01/2023] Open
Abstract
Surface plasmon resonance (SPR)-based optical biosensors offer real-time and label-free analysis of protein interactions, which has extensively contributed to the discovery and development of therapeutic monoclonal antibodies (mAbs). As the biopharmaceutical market for these biologics and their biosimilars is rapidly growing, the role of SPR biosensors in drug discovery and quality assessment is becoming increasingly prominent. One of the critical quality attributes of mAbs is the N-glycosylation of their Fc region. Other than providing stability to the antibody, the Fc N-glycosylation influences immunoglobulin G (IgG) interactions with the Fcγ receptors (FcγRs), modulating the immune response. Over the past two decades, several studies have relied on SPR-based assays to characterize the influence of N-glycosylation upon the IgG-FcγR interactions. While these studies have unveiled key information, many conclusions are still debated in the literature. These discrepancies can be, in part, attributed to the design of the reported SPR-based assays as well as the methodology applied to SPR data analysis. In fact, the SPR biosensor best practices have evolved over the years, and several biases have been pointed out in the development of experimental SPR protocols. In parallel, newly developed algorithms and data analysis methods now allow taking into consideration complex biomolecular kinetics. In this review, we detail the use of different SPR biosensing approaches for characterizing the IgG-FcγR interactions, highlighting their merit and inherent experimental complexity. Furthermore, we review the latest SPR-derived conclusions on the influence of the N-glycosylation upon the IgG-FcγR interactions and underline the differences and similarities across the literature. Finally, we explore new avenues taking advantage of novel computational analysis of SPR results as well as the latest strategies to control the glycoprofile of mAbs during production, which could lead to a better understanding and modelling of the IgG-FcγRs interactions.
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Manish M, Verma S, Kandari D, Kulshreshtha P, Singh S, Bhatnagar R. Anthrax prevention through vaccine and post-exposure therapy. Expert Opin Biol Ther 2020; 20:1405-1425. [DOI: 10.1080/14712598.2020.1801626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Manish Manish
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Shashikala Verma
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | - Divya Kandari
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Parul Kulshreshtha
- Department of Zoology, Shivaji College, University of Delhi, Delhi, India
| | - Samer Singh
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
- Department of Microbial Biotechnology, Panjab University, Chandigarh, India
| | - Rakesh Bhatnagar
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
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Human monoclonal anti-protective antigen antibody for the low-dose post-exposure prophylaxis and treatment of Anthrax. BMC Infect Dis 2018; 18:640. [PMID: 30526504 PMCID: PMC6288905 DOI: 10.1186/s12879-018-3542-6] [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: 01/17/2018] [Accepted: 11/23/2018] [Indexed: 12/21/2022] Open
Abstract
Background Disease caused by Bacillus anthracis is often accompanied by high mortality primarily due to toxin-mediated injury. In the early disease course, anthrax toxins are secreted; thus, antibiotic use is limited to the early stage. In this regard, antibodies against the toxin component, protective antigen (PA), play an important role in protecting against anthrax. Therefore, we developed PA21, a fully human anti-PA immunoglobulin G monoclonal antibody. Methods Combining human Fab was screened from a phage library with human heavy constant regions. Enzyme-linked immune sorbent assay, Western blot analysis and immunoprecipitation test evaluated the binding ability of PA21. Moreover, the affinity and neutralizing activity of the antibody was detected in vitro while the protective effectiveness in 60 rats was also examined in vivo. Results The Fischer 344 rats challenged with the lethal toxin can be protected by PA21 at a concentration of 0.067 mg/kg. All six rats remained alive although PA21 was injected 24 h before the toxin challenge. PA21 did not influence the binding of PA to cell receptors and that of a lethal factor to PA. Conclusion The PA21 monoclonal antibody against PA can be used for emergency prophylaxis and anthrax treatment.
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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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Ubah O, Palliyil S. Monoclonal Antibodies and Antibody Like Fragments Derived from Immunised Phage Display Libraries. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1053:99-117. [PMID: 29549637 PMCID: PMC7120432 DOI: 10.1007/978-3-319-72077-7_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Morbidity and mortality associated with infectious diseases are always on the rise, especially in poorer countries and in the aging population. The inevitable, but unpredictable emergence of new infectious diseases has become a global threat. HIV/AIDS, severe acute respiratory syndrome (SARS), and the more recent H1N1 influenza are only a few of the numerous examples of emerging infectious diseases in the modern era. However despite advances in diagnostics, therapeutics and vaccines, there is need for more specific, efficacious, cost-effective and less toxic treatment and preventive drugs. In this chapter, we discuss a powerful combinatorial technology in association with animal immunisation that is capable of generating biologic drugs with high affinity, efficacy and limited off-site toxicity, and diagnostic tools with great precision. Although time consuming, immunisation still remains the preferred route for the isolation of high-affinity antibodies and antibody-like fragments. Phage display is a molecular diversity technology that allows the presentation of large peptide and protein libraries on the surface of filamentous phage. The selection of binding fragments from phage display libraries has proven significant for routine isolation of invaluable peptides, antibodies, and antibody-like domains for diagnostic and therapeutic applications. Here we highlight the many benefits of combining immunisation with phage display in combating infectious diseases, and how our knowledge of antibody engineering has played a crucial role in fully exploiting these platforms in generating therapeutic and diagnostic biologics towards antigenic targets of infectious organisms.
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Affiliation(s)
- Obinna Ubah
- Scottish Biologics Facility, Elasmogen Ltd, Aberdeen, UK
| | - Soumya Palliyil
- Scottish Biologics Facility, University of Aberdeen, Aberdeen, UK.
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Langdon A, Crook N, Dantas G. The effects of antibiotics on the microbiome throughout development and alternative approaches for therapeutic modulation. Genome Med 2016; 8:39. [PMID: 27074706 PMCID: PMC4831151 DOI: 10.1186/s13073-016-0294-z] [Citation(s) in RCA: 515] [Impact Index Per Article: 64.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The widespread use of antibiotics in the past 80 years has saved millions of human lives, facilitated technological progress and killed incalculable numbers of microbes, both pathogenic and commensal. Human-associated microbes perform an array of important functions, and we are now just beginning to understand the ways in which antibiotics have reshaped their ecology and the functional consequences of these changes. Mounting evidence shows that antibiotics influence the function of the immune system, our ability to resist infection, and our capacity for processing food. Therefore, it is now more important than ever to revisit how we use antibiotics. This review summarizes current research on the short-term and long-term consequences of antibiotic use on the human microbiome, from early life to adulthood, and its effect on diseases such as malnutrition, obesity, diabetes, and Clostridium difficile infection. Motivated by the consequences of inappropriate antibiotic use, we explore recent progress in the development of antivirulence approaches for resisting infection while minimizing resistance to therapy. We close the article by discussing probiotics and fecal microbiota transplants, which promise to restore the microbiota after damage of the microbiome. Together, the results of studies in this field emphasize the importance of developing a mechanistic understanding of gut ecology to enable the development of new therapeutic strategies and to rationally limit the use of antibiotic compounds.
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Affiliation(s)
- Amy Langdon
- Center for Genome Sciences, Washington University School of Medicine, Campus Box 8510, 4515 McKinley Research Building, St. Louis, MO, 63108, USA
- Clinical Research Training Center, Washington University School of Medicine, Campus Box 8051, 660 South Euclid Avenue, St. Louis, MO, 63110-1093, USA
| | - Nathan Crook
- Center for Genome Sciences, Washington University School of Medicine, Campus Box 8510, 4515 McKinley Research Building, St. Louis, MO, 63108, USA
- Department of Pathology & Immunology, Washington University School of Medicine, Campus Box 8118, 660 South Euclid Ave, St. Louis, MO, 63110, USA
| | - Gautam Dantas
- Center for Genome Sciences, Washington University School of Medicine, Campus Box 8510, 4515 McKinley Research Building, St. Louis, MO, 63108, USA.
- Department of Pathology & Immunology, Washington University School of Medicine, Campus Box 8118, 660 South Euclid Ave, St. Louis, MO, 63110, USA.
- Department of Biomedical Engineering, Washington University in Saint Louis, Campus Box 1097, 1 Brookings Drive, Saint Louis, MO, 63130, USA.
- Department of Molecular Microbiology, Washington University School of Medicine, Campus Box 8230, 660 S. Euclid Ave, St. Louis, MO, 63110, USA.
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Xiong S, Tang Q, Liang X, Zhou T, Yang J, Liu P, Chen Y, Wang C, Feng Z, Zhu J. A Novel Chimeric Anti-PA Neutralizing Antibody for Postexposure Prophylaxis and Treatment of Anthrax. Sci Rep 2015; 5:11776. [PMID: 26134518 PMCID: PMC4488766 DOI: 10.1038/srep11776] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 05/28/2015] [Indexed: 12/11/2022] Open
Abstract
Anthrax is a highly lethal infectious disease caused by the bacterium Bacillus anthracis, and the associated shock is closely related to the lethal toxin (LeTx) produced by the bacterium. The central role played by the 63 kDa protective antigen (PA63) region of LeTx in the pathophysiology of anthrax makes it an excellent therapeutic target. In the present study, a human/murine chimeric IgG mAb, hmPA6, was developed by inserting murine antibody variable regions into human constant regions using antibody engineering technology. hmPA6 expressed in 293F cells could neutralize LeTx both in vitro and in vivo. At a dose of 0.3 mg/kg, it could protect all tested rats from a lethal dose of LeTx. Even administration of 0.6 mg/kg hmPA6 48 h before LeTx challenge protected all tested rats. The results indicate that hmPA6 is a potential candidate for clinical application in anthrax treatment.
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Affiliation(s)
- Siping Xiong
- 1] Department of Pathology, Nanjing Medical University, Nanjing 210029, China [2] Key Laboratory of Antibody Technique of Ministry of Health, Nanjing Medical University, Nanjing 210029, China
| | - Qi Tang
- Key Laboratory of Antibody Technique of Ministry of Health, Nanjing Medical University, Nanjing 210029, China
| | - Xudong Liang
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206 China
| | - Tingting Zhou
- Huadong Medical Institute of Biotechniques, Nanjing 210002, China
| | - Jin Yang
- Key Laboratory of Antibody Technique of Ministry of Health, Nanjing Medical University, Nanjing 210029, China
| | - Peng Liu
- Huadong Medical Institute of Biotechniques, Nanjing 210002, China
| | - Ya Chen
- 1] Department of Pathology, Nanjing Medical University, Nanjing 210029, China [2] Key Laboratory of Antibody Technique of Ministry of Health, Nanjing Medical University, Nanjing 210029, China
| | - Changjun Wang
- Huadong Medical Institute of Biotechniques, Nanjing 210002, China
| | - Zhenqing Feng
- 1] Department of Pathology, Nanjing Medical University, Nanjing 210029, China [2] Key Laboratory of Antibody Technique of Ministry of Health, Nanjing Medical University, Nanjing 210029, China
| | - Jin Zhu
- 1] Huadong Medical Institute of Biotechniques, Nanjing 210002, China [2] Key Laboratory of Antibody Technique of Ministry of Health, Nanjing Medical University, Nanjing 210029, China
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Bacillus anthracis Capsular Conjugates Elicit Chimpanzee Polyclonal Antibodies That Protect Mice from Pulmonary Anthrax. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2015; 22:902-8. [PMID: 26041039 DOI: 10.1128/cvi.00137-15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 05/17/2015] [Indexed: 01/12/2023]
Abstract
The immunogenicity of Bacillus anthracis capsule (poly-γ-D-glutamic acid [PGA]) conjugated to recombinant B. anthracis protective antigen (rPA) or to tetanus toxoid (TT) was evaluated in two anthrax-naive juvenile chimpanzees. In a previous study of these conjugates, highly protective monoclonal antibodies (MAbs) against PGA were generated. This study examines the polyclonal antibody response of the same animals. Preimmune antibodies to PGA with titers of >10(3) were detected in the chimpanzees. The maximal titer of anti-PGA was induced within 1 to 2 weeks following the 1st immunization, with no booster effects following the 2nd and 3rd immunizations. Thus, the anti-PGA response in the chimpanzees resembled a secondary immune response. Screening of sera from nine unimmunized chimpanzees and six humans revealed antibodies to PGA in all samples, with an average titer of 10(3). An anti-PA response was also observed following immunization with PGA-rPA conjugate, similar to that seen following immunization with rPA alone. However, in contrast to anti-PGA, preimmune anti-PA antibody titers and those following the 1st immunization were ≤300, with the antibodies peaking above 10(4) following the 2nd immunization. The polyclonal anti-PGA shared the MAb 11D epitope and, similar to the MAbs, exerted opsonophagocytic killing of B. anthracis. Most important, the PGA-TT-induced antibodies protected mice from a lethal challenge with virulent B. anthracis spores. Our data support the use of PGA conjugates, especially PGA-rPA targeting both toxin and capsule, as expanded-spectrum anthrax vaccines.
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Ohanjanian L, Remy KE, Li Y, Cui X, Eichacker PQ. An overview of investigational toxin-directed therapies for the adjunctive management of Bacillus anthracis infection and sepsis. Expert Opin Investig Drugs 2015; 24:851-65. [PMID: 25920540 DOI: 10.1517/13543784.2015.1041587] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Sepsis with Bacillus anthracis infection has a very high mortality rate despite appropriate antibiotic and supportive therapies. Over the past 15 years, recent outbreaks in the US and in Europe, coupled with anthrax's bioterrorism weapon potential, have stimulated efforts to develop adjunctive therapies to improve clinical outcomes. Since lethal toxin and edema toxin (LT and ET) make central contributions to the pathogenesis of B. anthracis, these have been major targets in this effort. AREAS COVERED Here, the authors review different investigative biopharmaceuticals that have been recently identified for their therapeutic potential as inhibitors of LT or ET. Among these inhibitors are two antibody preparations that have been included in the Strategic National Stockpile (SNS) and several more that have reached Phase I testing. Presently, however, many of these candidate agents have only been studied in vitro and very few tested in bacteria-challenged models. EXPERT OPINION Although a large number of drugs have been identified as potential therapeutic inhibitors of LT and ET, in most cases their testing has been limited. The use of the two SNS antibody therapies during a large-scale exposure to B. anthracis will be difficult. Further testing and development of agents with oral bioavailability and relatively long shelf lives should be a focus for future research.
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Affiliation(s)
- Lernik Ohanjanian
- National Institutes of Health, Clinical Center, Critical Care Medicine Department , Building 10, Room 2C145, Bethesda, MD 20892 , USA +1 301 402 2914 ; +1 301 402 1213 ;
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Generation and Characterization of Human Monoclonal Antibodies Targeting Anthrax Protective Antigen following Vaccination with a Recombinant Protective Antigen Vaccine. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2015; 22:553-60. [PMID: 25787135 DOI: 10.1128/cvi.00792-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 03/03/2015] [Indexed: 12/20/2022]
Abstract
The anthrax protective antigen (PA) is the central component of the three-part anthrax toxin, and it is the primary immunogenic component in the approved AVA anthrax vaccine and the "next-generation" recombinant PA (rPA) anthrax vaccines. Animal models have indicated that PA-specific antibodies (AB) are sufficient to protect against infection with Bacillus anthracis. In this study, we investigated the PA domain specificity, affinity, mechanisms of neutralization, and synergistic effects of PA-specific antibodies from a single donor following vaccination with the rPA vaccine. Antibody-secreting cells were isolated 7 days after the donor received a boost vaccination, and 34 fully human monoclonal antibodies (hMAb) were identified. Clones 8H6, 4A3, and 22F1 were able to neutralize lethal toxin (LeTx) both in vitro and in vivo. Clone 8H6 neutralized LeTx by preventing furin cleavage of PA in a dose-dependent manner. Clone 4A3 enhanced degradation of nicked PA, thereby interfering with PA oligomerization. The mechanism of 22F1 is still unclear. A fourth clone, 2A6, that was protective only in vitro was found to be neutralizing in vivo in combination with a toxin-enhancing antibody, 8A7, which binds to domain 3 of PA and PA oligomers. These results provide novel insights into the antibody response elicited by the rPA vaccine and may be useful for PA-based vaccine and immunotherapeutic cocktail design.
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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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Bouzianas DG. Potential biological targets ofBacillus anthracisin anti-infective approaches against the threat of bioterrorism. Expert Rev Anti Infect Ther 2014; 5:665-84. [PMID: 17678429 DOI: 10.1586/14787210.5.4.665] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The terrorist attacks of 2001 involving anthrax underscore the imperative that safe and effective medical countermeasures should be readily available. Vaccination appears to be the most effective form of mass protection against a biological attack, but the current vaccines have drawbacks that justify the enormous amount of effort currently being put into developing more effective vaccines and other treatment modalities. After providing a comprehensive overview of the organism Bacillus anthracis as a biological weapon and its pathogenicity, this review briefly summarizes the current knowledge vital to the management of anthrax disease. This knowledge has been acquired since 2001 as a result of the progress on anthrax research and focuses on the possible development of improved human anti-infective strategies targeting B. anthracis spore components, as well as strategies based on host-pathogen interactions.
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Affiliation(s)
- Dimitrios G Bouzianas
- Department of Medical Laboratories, Faculty of Health and Care Professions, University-level Technological Educational Institute of Thessaloniki, Greece.
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16
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Sizing up large protein complexes by electrospray ionisation-based electrophoretic mobility and native mass spectrometry: morphology selective binding of Fabs to hepatitis B virus capsids. Anal Bioanal Chem 2013; 406:1437-46. [PMID: 24357008 DOI: 10.1007/s00216-013-7548-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 11/29/2013] [Accepted: 12/02/2013] [Indexed: 12/29/2022]
Abstract
The capsid of hepatitis B virus (HBV) is a major viral antigen and important diagnostic indicator. HBV capsids have prominent protrusions ('spikes') on their surface and are unique in having either T = 3 or T = 4 icosahedral symmetry. Mouse monoclonal and also human polyclonal antibodies bind either near the spike apices (historically the 'α-determinant') or in the 'floor' regions between them (the 'β-determinant'). Native mass spectrometry (MS) and gas-phase electrophoretic mobility molecular analysis (GEMMA) were used to monitor the titration of HBV capsids with the antigen-binding domain (Fab) of mAb 3120, which has long defined the β-determinant. Both methods readily distinguished Fab binding to the two capsid morphologies and could provide accurate masses and dimensions for these large immune complexes, which range up to ~8 MDa. As such, native MS and GEMMA provide valuable alternatives to a more time-consuming cryo-electron microscopy analysis for preliminary characterisation of virus-antibody complexes.
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Development of Norwalk virus-specific monoclonal antibodies with therapeutic potential for the treatment of Norwalk virus gastroenteritis. J Virol 2013; 87:9547-57. [PMID: 23785216 DOI: 10.1128/jvi.01376-13] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Passive immunoprophylaxis or immunotherapy with norovirus-neutralizing monoclonal antibodies (MAbs) could be a useful treatment for high-risk populations, including infants and young children, the elderly, and certain patients who are debilitated or immunocompromised. In order to obtain antinorovirus MAbs with therapeutic potential, we stimulated a strong adaptive immune response in chimpanzees to the prototype norovirus strain Norwalk virus (NV) (genogroup I.1). A combinatorial phage Fab display library derived from mRNA of the chimpanzees' bone marrow was prepared, and four distinct Fabs reactive with Norwalk recombinant virus-like particles (rVLPs) were recovered, with estimated binding affinities in the subnanomolar range. Mapping studies showed that the four Fabs recognized three different conformational epitopes in the protruding (P) domain of NV VP1, the major capsid protein. The epitope of one of the Fabs, G4, was further mapped to a specific site involving a key amino acid residue, Gly365. One additional specific Fab (F11) was recovered months later from immortalized memory B cells and partially characterized. The anti-NV Fabs were converted into full-length IgG (MAbs) with human γ1 heavy chain constant regions. The anti-NV MAbs were tested in the two available surrogate assays for Norwalk virus neutralization, which showed that the MAbs could block carbohydrate binding and inhibit hemagglutination by NV rVLP. By mixing a single MAb with live Norwalk virus prior to challenge, MAbs D8 and B7 neutralized the virus and prevented infection in a chimpanzee. Because chimpanzee immunoglobulins are virtually identical to human immunoglobulins, these chimpanzee anticapsid MAbs may have a clinical application.
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Oleksiewicz MB, Nagy G, Nagy E. Anti-bacterial monoclonal antibodies: Back to the future? Arch Biochem Biophys 2012; 526:124-31. [DOI: 10.1016/j.abb.2012.06.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 06/01/2012] [Accepted: 06/02/2012] [Indexed: 01/08/2023]
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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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Smith K, Crowe SR, Garman L, Guthridge CJ, Muther JJ, McKee E, Zheng NY, Farris AD, Guthridge JM, Wilson PC, James JA. Human monoclonal antibodies generated following vaccination with AVA provide neutralization by blocking furin cleavage but not by preventing oligomerization. Vaccine 2012; 30:4276-83. [PMID: 22425791 DOI: 10.1016/j.vaccine.2012.03.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 02/09/2012] [Accepted: 03/01/2012] [Indexed: 12/28/2022]
Abstract
In order to identify the combination of antibody-mediated mechanisms of neutralization that result from vaccination with anthrax vaccine adsorbed (AVA), we isolated antibody secreting cells from a single donor seven days after booster vaccination with AVA and generated nine fully human monoclonal antibodies (hmAb) with high specificity for protective antigen (PA). Two of the antibodies were able to neutralize lethal toxin in vitro at low concentrations (IC(50): p6C01, 0.12 μg/ml and p6F01, 0.45 μg/ml). Passive transfer of either of these hmAbs to A/J mice prior to challenge with lethal toxin conferred 80-90% protection. We demonstrate that hmAb p6C01 is neutralizing by preventing furin cleavage of PA in a dose-dependent manner, but the mechanism of p6F01 is unclear. Three additional antibodies were found to bind to domain 3 of PA and prevent oligomerization, although they did not confer significant protection in vivo and showed a significant prozone-like effect in vitro. These fully human antibodies provide insight into the neutralizing response to AVA for future subunit vaccine and passive immunotherapeutic cocktail design.
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Affiliation(s)
- Kenneth Smith
- Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK 73104, USA
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Vuyisich M, Sanders CK, Graves SW. Binding and cell intoxication studies of anthrax lethal toxin. Mol Biol Rep 2012; 39:5897-903. [PMID: 22219086 DOI: 10.1007/s11033-011-1401-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 12/17/2011] [Indexed: 11/25/2022]
Abstract
Anthrax lethal toxin (LT) is a major virulence factor of Bacillus anthracis. The vast majority of the anthrax toxin-related literature describes the assembly of LT as a cell-dependent process. However, some reports have provided evidence for the existence of a fully assembled LT, either in vitro or in the bloodstream of anthrax-infected animals. To follow up on this work, we present studies on fully-assembled LT. We first demonstrate facile and cell-free assembly and purification of LT. We then show that fully assembled LT binds an anthrax toxin receptor with almost 100-fold higher affinity than the protective antigen (PA) alone. Quantitative cell intoxication assays were used to determine the LD(50) (lethal dose 50) for LT. The cell-binding studies revealed that LT binds mammalian cells using a different mode from PA. Even when PA-specific receptors were blocked, fully assembled LT was able to bind the cell surface. Our studies support the existing evidence that LT fully assembles in the blood stream and can bind and intoxicate mammalian cells with very high affinity and efficacy. More importantly, the data presented here invoke the possibility that LT may bind cells in a receptor-independent fashion, or recognize receptors that do not interact with PA. Hence, blood borne LT may emerge as a novel therapeutic target for combating anthrax.
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Affiliation(s)
- Momchilo Vuyisich
- Los Alamos National Lab, MS M888, P.O. Box 1663, Los Alamos, NM 87545, USA.
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Gjelstrup LC, Kaspersen JD, Behrens MA, Pedersen JS, Thiel S, Kingshott P, Oliveira CLP, Thielens NM, Vorup-Jensen T. The role of nanometer-scaled ligand patterns in polyvalent binding by large mannan-binding lectin oligomers. THE JOURNAL OF IMMUNOLOGY 2012; 188:1292-306. [PMID: 22219330 DOI: 10.4049/jimmunol.1103012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Mannan-binding lectin (MBL) is an important protein of the innate immune system and protects the body against infection through opsonization and activation of the complement system on surfaces with an appropriate presentation of carbohydrate ligands. The quaternary structure of human MBL is built from oligomerization of structural units into polydisperse complexes typically with three to eight structural units, each containing three lectin domains. Insight into the connection between the structure and ligand-binding properties of these oligomers has been lacking. In this article, we present an analysis of the binding to neoglycoprotein-coated surfaces by size-fractionated human MBL oligomers studied with small-angle x-ray scattering and surface plasmon resonance spectroscopy. The MBL oligomers bound to these surfaces mainly in two modes, with dissociation constants in the micro to nanomolar order. The binding kinetics were markedly influenced by both the density of ligands and the number of ligand-binding domains in the oligomers. These findings demonstrated that the MBL-binding kinetics are critically dependent on structural characteristics on the nanometer scale, both with regard to the dimensions of the oligomer, as well as the ligand presentation on surfaces. Therefore, our work suggested that the surface binding of MBL involves recognition of patterns with dimensions on the order of 10-20 nm. The recent understanding that the surfaces of many microbes are organized with structural features on the nanometer scale suggests that these properties of MBL ligand recognition potentially constitute an important part of the pattern-recognition ability of these polyvalent oligomers.
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Affiliation(s)
- Louise C Gjelstrup
- Biophysical Immunology Laboratory, Aarhus University, DK-8000 Aarhus C, Denmark
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Makiya M, Dolan M, Agulto L, Purcell R, Chen Z. Structural basis of anthrax edema factor neutralization by a neutralizing antibody. Biochem Biophys Res Commun 2011; 417:324-9. [PMID: 22155239 DOI: 10.1016/j.bbrc.2011.11.108] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 11/19/2011] [Indexed: 11/16/2022]
Abstract
Fine epitope mapping of EF13D, a highly potent neutralizing monoclonal antibody specific for the anthrax edema factor (EF), was accomplished through random mutagenesis and yeast surface display. A yeast-displayed library of single point mutants of an EF domain III (DIII), comprising amino acids 624-800, was constructed by random mutagenesis and screened for reduced binding to EF13D. With this method, residues Leu 667, Ser 668, Arg 671, and Arg 672 were identified as key residues important for EF13D binding. They form a contiguous patch on a solvent-exposed surface at one end of the four-helix bundle of DIII. Computational protein-protein docking experiments between anEF13D model and a crystal structure of EF indicate that the EF13D heavy chain complementarity-determining region 3 (HCDR3) is deeply buried within a hydrophobic cleft between two helices of DIII and interacts directly with residues Leu 667, Ser 668, Arg 671 and Arg 672, providing an explanation for the high binding affinity. In addition, they show that the HCDR3 binding site overlaps with the binding site of the N-terminal lobe of calmodulin (CaM), an EF enzymatic activator, consistent with a previous finding showing direct competition with CaM that results in neutralization of EF. Identifying the neutralization epitope of EF13D on EF improves our understanding of the neutralization mechanism and has implications for vaccine development.
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Affiliation(s)
- Michelle Makiya
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, United States
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Antibodies against anthrax: mechanisms of action and clinical applications. Toxins (Basel) 2011; 3:1433-52. [PMID: 22174979 PMCID: PMC3237005 DOI: 10.3390/toxins3111433] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 11/03/2011] [Accepted: 11/07/2011] [Indexed: 12/23/2022] Open
Abstract
B. anthracis is a bioweapon of primary importance and its pathogenicity depends on its lethal and edema toxins, which belong to the A-B model of bacterial toxins, and on its capsule. These toxins are secreted early in the course of the anthrax disease and for this reason antibiotics must be administered early, in addition to other limitations. Antibodies (Abs) may however neutralize those toxins and target this capsule to improve anthrax treatment, and many Abs have been developed in that perspective. These Abs act at various steps of the cell intoxication and their mechanisms of action are detailed in the present review, presented in correlation with structural and functional data. The potential for clinical application is discussed for Abs targeting each step of entry, with four of these molecules already advancing to clinical trials. Paradoxically, certain Abs may also enhance the lethal toxin activity and this aspect will also be presented. The unique paradigm of Abs neutralizing anthrax toxins thus exemplifies how they may act to neutralize A-B toxins and, more generally, be active against infectious diseases.
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Monoclonal antibody therapies against anthrax. Toxins (Basel) 2011; 3:1004-19. [PMID: 22069754 PMCID: PMC3202866 DOI: 10.3390/toxins3081004] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 08/06/2011] [Accepted: 08/10/2011] [Indexed: 12/15/2022] Open
Abstract
Anthrax is a highly lethal infectious disease caused by the spore-forming bacterium Bacillus anthracis. It not only causes natural infection in humans but also poses a great threat as an emerging bioterror agent. The lethality of anthrax is primarily attributed to the two major virulence factors: toxins and capsule. An extensive effort has been made to generate therapeutically useful monoclonal antibodies to each of the virulence components: protective antigen (PA), lethal factor (LF) and edema factor (EF), and the capsule of B. anthracis. This review summarizes the current status of anti-anthrax mAb development and argues for the potential therapeutic advantage of a cocktail of mAbs that recognize different epitopes or different virulence factors.
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Altaweel L, Chen Z, Moayeri M, Cui X, Li Y, Su J, Fitz Y, Johnson S, Leppla SH, Purcell R, Eichacker PQ. Delayed treatment with W1-mAb, a chimpanzee-derived monoclonal antibody against protective antigen, reduces mortality from challenges with anthrax edema or lethal toxin in rats and with anthrax spores in mice. Crit Care Med 2011; 39:1439-47. [PMID: 21336113 DOI: 10.1097/ccm.0b013e3182120691] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE W1-mAb is a chimpanzee-derived monoclonal antibody to protective antigen that improved survival when administered before anthrax lethal toxin challenge in rats. To better define W1-mAb's efficacy for anthrax, we administered it after initiation of 24-hr infusions of edema toxin and lethal toxin either alone or together in rats or following anthrax spore challenge in mice. INTERVENTIONS W1-mAb or placebo treatment. METHODS AND MAIN RESULTS In toxin-challenged rats treated with placebo, survival rates were lower with edema toxin (500 μg/kg) compared to lethal toxin either alone (175 μg/kg) or with edema toxin (175 μg/kg each) (8%, 33%, and 32%, respectively), but the median time to death was longer (36, 11, and 9 hrs, respectively) (p ≤ .01 for all comparisons). W1-mAb administered up to 12 hrs after edema toxin and 6 hrs after lethal toxin increased survival and reduced hypotension (p ≤ .01). However, only administration of W1-mAb at 0 hrs improved these variables with lethal toxin and edema toxin together (p ≤ .0002). In C57BL/6J mice challenged with anthrax spores subcutaneously, compared to placebo treatment (0 of 15 animals survived), W1-mAb administered beginning 24 hrs after challenge increased survival (13 of 15 survived) (p ≤ .0001). CONCLUSION While rapidity of lethality may influence the effectiveness of delayed W1-mAb treatment, these rat and mouse studies provide a basis for further exploring this agent's usefulness for anthrax.
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Affiliation(s)
- Laith Altaweel
- Critical Care Medicine Department, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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Inhibition of anthrax toxins with a bispecific monoclonal antibody that cross reacts with edema factor as well as lethal factor of Bacillus anthracis. Mol Immunol 2011; 48:1958-65. [PMID: 21704379 DOI: 10.1016/j.molimm.2011.05.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 05/26/2011] [Accepted: 05/26/2011] [Indexed: 01/29/2023]
Abstract
Bacillus anthracis overwhelms its victims by way of two toxins, namely edema toxin and lethal toxin. Lethal toxin is formed by the combination of protective antigen with lethal factor while edema toxin is formed by the combination of Protective Antigen with edema factor. Overlapping regions between edema factor and lethal factor have been reported in past. For the first time, this study reports characterization of a bispecific monoclonal antibody (mAb), H10, which showed high affinity interaction with both edema factor and lethal factor of B. anthracis. H10 mAb not only neutralized the adenylate cyclase activity of edema toxin but it could also neutralize the cytotoxic activity of lethal toxin. Passive immunization with this antibody gave 100% protection to mice from in vivo challenge with lethal toxin and edema toxin. The results of this study suggest future application of this bispecific monoclonal antibody as passive immunization prophylactics in cases of B. anthracis exposure and infection.
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Abstract
Human inter-α inhibitor proteins are endogenous human plasma proteins that function as serine protease inhibitors. Inter-α inhibitor proteins can block the systemic release of proteases in sepsis and block furin-mediated assembly of protective antigen, an essential stop in the intracellular delivery of the anthrax exotoxins, lethal toxin and edema toxin. Inter-α inhibitor proteins administered on hour or up to 24 h after spore challenge with Bacillus anthracis Sterne strain protected mice from lethality if administered with antimicrobial therapy (P < 0.001). These human plasma proteins possess combined actions against anthrax as general inhibitors of excess serine proteases in sepsis and specific inhibitors of anthrax toxin assembly. Inter-α inhibitor proteins could represent a novel adjuvant therapy for the treatment of established anthrax infection.
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Chimpanzee-human monoclonal antibodies for treatment of chronic poliovirus excretors and emergency postexposure prophylaxis. J Virol 2011; 85:4354-62. [PMID: 21345966 DOI: 10.1128/jvi.02553-10] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Six poliovirus-neutralizing Fabs were recovered from a combinatorial Fab phage display library constructed from bone marrow-derived lymphocytes of immunized chimpanzees. The chimeric chimpanzee-human full-length IgGs (hereinafter called monoclonal antibodies [MAbs]) were generated by combining a chimpanzee IgG light chain and a variable domain of heavy chain with a human constant Fc region. The six MAbs neutralized vaccine strains and virulent strains of poliovirus. Five MAbs were serotype specific, while one MAb cross-neutralized serotypes 1 and 2. Epitope mapping performed by selecting and sequencing antibody-resistant viral variants indicated that the cross-neutralizing MAb bound between antigenic sites 1 and 2, thereby covering the canyon region containing the receptor-binding site. Another serotype 1-specific MAb recognized a region located between antigenic sites 2 and 3 that included parts of capsid proteins VP1 and VP3. Both serotype 2-specific antibodies recognized antigenic site 1. No escape mutants to serotype 3-specific MAbs could be generated. The administration of a serotype 1-specific MAb to transgenic mice susceptible to poliovirus at a dose of 5 μg/mouse completely protected them from paralysis after challenge with a lethal dose of wild-type poliovirus. Moreover, MAb injection 6 or 12 h after virus infection provided significant protection. The MAbs described here could be tested in clinical trials to determine whether they might be useful for treatment of immunocompromised chronic virus excretors and for emergency protection of contacts of a paralytic poliomyelitis case.
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Chen Z, Schneerson R, Lovchik J, Lyons CR, Zhao H, Dai Z, Kubler-Kielb J, Leppla SH, Purcell RH. Pre- and postexposure protection against virulent anthrax infection in mice by humanized monoclonal antibodies to Bacillus anthracis capsule. Proc Natl Acad Sci U S A 2011; 108:739-44. [PMID: 21187383 PMCID: PMC3021070 DOI: 10.1073/pnas.1017677108] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
One of the two essential virulence factors of Bacillus anthracis is the poly-γ-D-glutamic acid (γDPGA) capsule. Five γDPGA-specific antibody antigen-binding fragments (Fabs) were generated from immunized chimpanzees. The two selected for further study, Fabs 11D and 4C, were both converted into full-length IgG1 and IgG3 mAbs having human IgG1 or IgG3 constant regions. These two mAbs had similar binding affinities, in vitro opsonophagocytic activities, and in vivo efficacies, with the IgG1 and IgG3 subclasses reacting similarly. The mAbs bound to γDPGA specifically with estimated binding affinities (K(d)) of 35-70 nM and effective affinities (effective K(d)) of 0.1-0.3 nM. The LD(50) in an opsonophagocytic bactericidal assay was ≈10 ng/mL of 11D or 4C. A single 30-μg dose of either mAb given to BALB/c mice 18 h before challenge conferred about 50% protection against a lethal intratracheal spore challenge by the virulent B. anthracis Ames strain. More importantly, either mAb given 8 h or 20 h after challenge provided significant protection against lethal infection. Thus, these anti-γDPGA mAbs should be useful, alone or in combination with antitoxin mAbs, for achieving a safe and efficacious postexposure therapy for anthrax.
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Affiliation(s)
| | - Rachel Schneerson
- Program on Developmental and Molecular Immunity, National Institute of Child Health and Human Development, and
| | - Julie Lovchik
- Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131
| | - C. Rick Lyons
- Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131
| | - Huaying Zhao
- National Institute for Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892; and
| | - Zhongdong Dai
- Program on Developmental and Molecular Immunity, National Institute of Child Health and Human Development, and
| | - Joanna Kubler-Kielb
- Program on Developmental and Molecular Immunity, National Institute of Child Health and Human Development, and
| | - Stephen H. Leppla
- Laboratory of Bacterial Diseases, National Institute of Allergy and Infectious Diseases
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32
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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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33
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Bouzianas DG. Current and future medical approaches to combat the anthrax threat. J Med Chem 2010; 53:4305-31. [PMID: 20102155 DOI: 10.1021/jm901024b] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Dimitrios G Bouzianas
- Laboratory of Molecular Endocrinology, Division of Endocrinology and Metabolism, AHEPA University Hospital, 1 S. Kyriakidi Street, P.C. 54636, Thessaloniki, Macedonia, Greece.
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Abstract
Antibiotic resistance is one of the greatest challenges of the twenty-first century. However, the increasing understanding of bacterial pathogenesis and intercellular communication has revealed many potential strategies to develop novel drugs to treat bacteria-mediated disease. Interference with bacterial virulence and/or cell-to-cell signalling pathways is an especially compelling approach, as it is thought to apply less selective pressure for the development of bacterial resistance than traditional strategies, which are aimed at killing bacteria or preventing their growth. Here, we discuss the mechanisms of bacterial virulence and present promising anti-virulence strategies and compounds for the future treatment of bacterial infections.
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35
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Bouzianas DG. Medical countermeasures to protect humans from anthrax bioterrorism. Trends Microbiol 2009; 17:522-8. [PMID: 19781945 DOI: 10.1016/j.tim.2009.08.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 07/25/2009] [Accepted: 08/24/2009] [Indexed: 12/27/2022]
Abstract
The deliberate dissemination of Bacillus anthracis spores via the US mail system in 2001 confirmed their potential use as a biological weapon for mass human casualties. This dramatically highlighted the need for specific medical countermeasures to enable the authorities to protect individuals from a future bioterrorism attack. Although vaccination appears to be the most effective and economical form of mass protection, current vaccines have significant drawbacks that justify the immense research effort to develop improved treatment modalities. After eight years and an expenditure of more than $50 billion, only marginal progress has been made in developing effective therapeutics. This article summarizes the most important medical countermeasures that have mostly been developed since the 2001 events, and highlights current problems and possible avenues for future research.
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Affiliation(s)
- Dimitrios G Bouzianas
- Technological Educational Institute of Thessaloniki, Department of Medical Laboratories, Laboratory of Immunology and Microbiology, PO Box 145-61, Thessaloniki 541-01, Macedonia, Greece.
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36
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Neutralizing monoclonal antibodies directed against defined linear epitopes on domain 4 of anthrax protective antigen. Infect Immun 2009; 77:4859-67. [PMID: 19703971 DOI: 10.1128/iai.00117-09] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The anthrax protective antigen (PA) is the receptor-binding subunit common to lethal toxin (LT) and edema toxin (ET), which are responsible for the high mortality rates associated with inhalational Bacillus anthracis infection. Although recombinant PA (rPA) is likely to be an important constituent of any future anthrax vaccine, evaluation of the efficacies of the various candidate rPA vaccines is currently difficult, because the specific B-cell epitopes involved in toxin neutralization have not been completely defined. In this study, we describe the identification and characterization of two murine monoclonal immunoglobulin G1 antibodies (MAbs), 1-F1 and 2-B12, which recognize distinct linear neutralizing epitopes on domain 4 of PA. 1-F1 recognized a 12-mer peptide corresponding to residues 692 to 703; this epitope maps to a region of domain 4 known to interact with the anthrax toxin receptor CMG-2 and within a conformation-dependent epitope recognized by the well-characterized neutralizing MAb 14B7. As expected, 1-F1 blocked PA's ability to associate with CMG-2 in an in vitro solid-phase binding assay, and it protected murine macrophage cells from intoxication with LT. 2-B12 recognized a 12-mer peptide corresponding to residues 716 to 727, an epitope located immediately adjacent to the core 14B7 binding site and a stretch of amino acids not previously identified as a target of neutralizing antibodies. 2-B12 was as effective as 1-F1 in neutralizing LT in vitro, although it only partially inhibited PA binding to its receptor. Mice passively administered 1-F1 or 2-B12 were partially protected against a lethal challenge with LT. These results advance our fundamental understanding of the mechanisms by which antibodies neutralize anthrax toxin and may have future application in the evaluation of candidate rPA vaccines.
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37
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Chen Z, Moayeri M, Zhao H, Crown D, Leppla SH, Purcell RH. Potent neutralization of anthrax edema toxin by a humanized monoclonal antibody that competes with calmodulin for edema factor binding. Proc Natl Acad Sci U S A 2009; 106:13487-92. [PMID: 19651602 PMCID: PMC2726367 DOI: 10.1073/pnas.0906581106] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Indexed: 11/18/2022] Open
Abstract
This study describes the isolation and characterization of a neutralizing monoclonal antibody (mAb) against anthrax edema factor, EF13D. EF13D neutralized edema toxin (ET)-mediated cyclic AMP (cAMP) responses in cells and protected mice from both ET-induced footpad edema and systemic ET-mediated lethality. The antibody epitope was mapped to domain IV of EF. The mAb was able to compete with calmodulin (CaM) for EF binding and displaced CaM from EF-CaM complexes. EF-mAb binding affinity (0.05-0.12 nM) was 50- to 130-fold higher than that reported for EF-CaM. This anti-EF neutralizing mAb could potentially be used alone or with an anti-PA mAb in the emergency prophylaxis and treatment of anthrax infection.
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Affiliation(s)
| | - Mahtab Moayeri
- Laboratory of Bacterial Diseases, National Institute of Allergy and Infectious Diseases, and
| | - Huaying Zhao
- National Institute for Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
| | - Devorah Crown
- Laboratory of Bacterial Diseases, National Institute of Allergy and Infectious Diseases, and
| | - Stephen H. Leppla
- Laboratory of Bacterial Diseases, National Institute of Allergy and Infectious Diseases, and
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38
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Rosenfeld R, Marcus H, Ben-Arie E, Lachmi BE, Mechaly A, Reuveny S, Gat O, Mazor O, Ordentlich A. Isolation and chimerization of a highly neutralizing antibody conferring passive protection against lethal Bacillus anthracis infection. PLoS One 2009; 4:e6351. [PMID: 19629185 PMCID: PMC2710523 DOI: 10.1371/journal.pone.0006351] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2009] [Accepted: 06/22/2009] [Indexed: 11/18/2022] Open
Abstract
Several studies have demonstrated that the passive transfer of protective antigen (PA)-neutralizing antibodies can protect animals against Bacillus anthracis infection. The standard protocol for the isolation of PA-neutralizing monoclonal antibodies is based upon a primary selection of the highest PA-binders by ELISA, and usually yields only few candidates antibodies. We demonstrated that by applying a PA-neutralization functionality-based screen as the primary criterion for positive clones, it was possible to isolate more than 100 PA-neutralizing antibodies, some of which exhibited no measurable anti-PA titers in ELISA. Among the large panel of neutralizing antibodies identified, mAb 29 demonstrated the most potent activity, and was therefore chimerized. The variable region genes of the mAb 29 were fused to human constant region genes, to form the chimeric 29 antibody (cAb 29). Guinea pigs were fully protected against infection by 40LD(50)B. anthracis spores following two separate administrations with 10 mg/kg of cAb 29: the first administration was given before the challenge, and a second dose was administered on day 4 following exposure. Moreover, animals that survived the challenge and developed endogenous PA-neutralizing antibodies with neutralizing titers above 100 were fully protected against repeat challenges with 40LD(50) of B. anthracis spores. The data presented here emphasize the importance of toxin neutralization-based screens for the efficient isolation of protective antibodies that were probably overlooked in the standard screening protocol. The protective activity of the chimeric cAb 29 demonstrated in this study suggest that it may serve as an effective immunotherapeutic agent against anthrax.
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Affiliation(s)
- Ronit Rosenfeld
- Departments of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Hadar Marcus
- Department of Biotechnology, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Einat Ben-Arie
- Departments of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Bat-El Lachmi
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Adva Mechaly
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Shaul Reuveny
- Department of Biotechnology, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Orit Gat
- Departments of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Ohad Mazor
- Departments of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Arie Ordentlich
- Departments of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
- * E-mail:
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39
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Novel chimpanzee/human monoclonal antibodies that neutralize anthrax lethal factor, and evidence for possible synergy with anti-protective antigen antibody. Infect Immun 2009; 77:3902-8. [PMID: 19528217 DOI: 10.1128/iai.00200-09] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Three chimpanzee Fabs reactive with lethal factor (LF) of anthrax toxin were isolated and converted into complete monoclonal antibodies (MAbs) with human gamma1 heavy-chain constant regions. In a macrophage toxicity assay, two of the MAbs, LF10E and LF11H, neutralized lethal toxin (LT), a complex of LF and anthrax protective antigen (PA). LF10E has the highest reported affinity for a neutralizing MAb against LF (dissociation constant of 0.69 nM). This antibody also efficiently neutralized LT in vitro, with a 50% effective concentration (EC(50)) of 0.1 nM, and provided 100% protection of rats against toxin challenge with a 0.5 submolar ratio relative to LT. LF11H, on the other hand, had a slightly lower binding affinity to LF (dissociation constant of 7.4 nM) and poor neutralization of LT in vitro (EC(50) of 400 nM) and offered complete protection in vivo only at an equimolar or higher ratio to toxin. Despite this, LF11H, but not LF10E, provided robust synergistic protection when combined with MAb W1, which neutralizes PA. Epitope mapping and binding assays indicated that both LF10E and LF11H recognize domain I of LF (amino acids 1 to 254). Although domain I is responsible for binding to PA, neither MAb prevented LF from binding to activated PA. Although two unique MAbs could protect against anthrax when used alone, even more efficient and broader protection should be gained by combining them with anti-PA MAbs.
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40
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Vuyisich M, Gnanakaran S, Lovchik JA, Lyons CR, Gupta G. A dual-purpose protein ligand for effective therapy and sensitive diagnosis of anthrax. Protein J 2009; 27:292-302. [PMID: 18649128 DOI: 10.1007/s10930-008-9137-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This article reports the design of a bivalent protein ligand with dual use in therapy and diagnosis of anthrax caused by Bacillus anthracis. The ligand specifically binds to PA and thereby blocks the intracellular delivery of LF and EF toxins that, respectively, cause cell lysis and edema. The ligand is a chimeric scaffold with two PA-binding domains (called VWA) linked to an IgG-Fc frame. Molecular modeling and binding measurements reveal that the VWA-Fc dimer binds to PA with high affinity (K(D)=0.2 nM). An in vitro bio-luminescence assay shows that VWA-Fc (at nanomolar concentration) protects mouse macrophages from lysis by PA/LF. In vivo studies demonstrate that VWA-Fc at low doses (approximately 50 microg/animal) are able to rescue animals from lethal doses of PA/LF and B. anthracis spores. Finally, VWA-Fc is utilized as the capture molecule in the sensitive (down to 30 picomolar) detection of PA using surface plasmon resonance.
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Affiliation(s)
- Momchilo Vuyisich
- Biosciences Division, Group B-7, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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41
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Crystal structure of the engineered neutralizing antibody M18 complexed to domain 4 of the anthrax protective antigen. J Mol Biol 2009; 387:680-93. [PMID: 19361425 DOI: 10.1016/j.jmb.2009.02.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 02/03/2009] [Accepted: 02/03/2009] [Indexed: 11/24/2022]
Abstract
The virulence of Bacillus anthracis is critically dependent on the cytotoxic components of the anthrax toxin, lethal factor (LF) and edema factor (EF). LF and EF gain entry into host cells through interactions with the protective antigen (PA), which binds to host cellular receptors such as CMG2. Antibodies that neutralize PA have been shown to confer protection in animal models and are undergoing intense clinical development. A murine monoclonal antibody, 14B7, has been reported to interact with domain 4 of PA (PAD4) and block its binding to CMG2. More recently, the 14B7 antibody was used as the platform for the selection of very high affinity, single-chain antibodies that have tremendous potential as a combination anthrax prophylactic and treatment. Here, we report the high-resolution X-ray structures of three high-affinity, single-chain antibodies in the 14B7 family; 14B7 and two high-affinity variants 1H and M18. In addition, we present the first neutralizing antibody-PA structure, M18 in complex with PAD4 at 3.8 A resolution. These structures provide insights into the mechanism of neutralization, and the effect of various mutations on antibody affinity, and enable a comparison between the binding of the M18 antibody and CMG2 with PAD4.
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42
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Detection of anthrax toxin by an ultrasensitive immunoassay using europium nanoparticles. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2009; 16:408-13. [PMID: 19129473 DOI: 10.1128/cvi.00412-08] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We developed a europium nanoparticle-based immunoassay (ENIA) for the sensitive detection of anthrax protective antigen (PA). The ENIA exhibited a linear dose-dependent pattern within the detection range of 0.01 to 100 ng/ml and was approximately 100-fold more sensitive than enzyme-linked immunosorbent assay (ELISA). False-positive results were not observed with serum samples from healthy adults, mouse plasma without PA, or plasma samples collected from mice injected with anthrax lethal factor or edema factor alone. For the detection of plasma samples spiked with PA, the detection sensitivities for ENIA and ELISA were 100% (11/11 samples) and 36.4% (4/11 samples), respectively. The assay exhibited a linear but qualitative correlation between the PA injected and the PA detected in murine blood (r=0.97731; P<0.0001). Anthrax PA was also detected in the circulation of mice infected with spores from a toxigenic Sterne-like strain of Bacillus anthracis, but only in the later stages of infection. These results indicate that the universal labeling technology based on europium nanoparticles and its application may provide a rapid and sensitive testing platform for clinical diagnosis and laboratory research.
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43
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Gorshkova II, Svitel J, Razjouyan F, Schuck P. Bayesian analysis of heterogeneity in the distribution of binding properties of immobilized surface sites. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:11577-86. [PMID: 18816013 PMCID: PMC2574969 DOI: 10.1021/la801186w] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Once a homogeneous ensemble of a protein ligand is taken from solution and immobilized to a surface, for many reasons the resulting ensemble of surface binding sites to soluble analytes may be heterogeneous. For example, this can be due to the intrinsic surface roughness causing variations in the local microenvironment, nonuniform density distribution of polymeric linkers, or nonuniform chemical attachment producing different protein orientations and conformations. We previously described a computational method for determining the distribution of affinity and rate constants of surface sites from analysis of experimental surface binding data. It fully exploits the high signal/noise ratio and reproducibility provided by optical biosensor technology, such as surface plasmon resonance. Since the computational analysis is ill conditioned, the previous approach used a regularization strategy assuming a priori all binding parameters to be equally likely, resulting in the broadest possible parameter distribution consistent with the experimental data. We now extended this method in a Bayesian approach to incorporate the opposite assumption, i.e., that the surface sites a priori are expected to be uniform (as one would expect in free solution). This results in a distribution of binding parameters as close to monodispersity as possible given the experimental data. Using several model protein systems immobilized on a carboxymethyl dextran surface and probed with surface plasmon resonance, we show microheterogeneity of the surface sites in addition to broad populations of significantly altered affinity. The distributions obtained are highly reproducible. Immobilization conditions and the total surface density of immobilized sites can have a substantial impact on the functional distribution of the binding sites.
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Affiliation(s)
- Inna I. Gorshkova
- Dynamics of Macromolecular Assembly Section, Laboratory of Bioengineering and Physical Science, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
| | | | - Faezeh Razjouyan
- Dynamics of Macromolecular Assembly Section, Laboratory of Bioengineering and Physical Science, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
| | - Peter Schuck
- Dynamics of Macromolecular Assembly Section, Laboratory of Bioengineering and Physical Science, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
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44
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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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45
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Affiliation(s)
- Sean V Shadomy
- Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
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46
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Improvement of an Antibody Neutralizing the Anthrax Toxin by Simultaneous Mutagenesis of Its Six Hypervariable Loops. J Mol Biol 2008; 378:1094-103. [DOI: 10.1016/j.jmb.2008.03.045] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2007] [Revised: 03/17/2008] [Accepted: 03/21/2008] [Indexed: 11/22/2022]
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47
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In vivo efficacy of beta-cyclodextrin derivatives against anthrax lethal toxin. Antimicrob Agents Chemother 2008; 52:2239-41. [PMID: 18378717 DOI: 10.1128/aac.00009-08] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We evaluated the in vivo efficacy of three beta-cyclodextrin derivatives that block the anthrax protective antigen pore. These compounds were at least 15-fold more potent than previously described beta-cyclodextrins in protecting against anthrax lethal toxin in a rat model. One of the drugs was shown to protect mice from bacterial infection.
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48
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Antibody Phage Display. SPRINGER PROTOCOLS HANDBOOKS 2008. [PMCID: PMC7123299 DOI: 10.1007/978-1-60327-375-6_34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Li Y, Sherer K, Cui X, Eichacker PQ. New insights into the pathogenesis and treatment of anthrax toxin-induced shock. Expert Opin Biol Ther 2007; 7:843-54. [PMID: 17555370 DOI: 10.1517/14712598.7.6.843] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Inhalational Bacillus anthracis infection is a leading bioterrorist health threat in the US today. Lethal (LeTx) and edema toxin production are key to the virulent effects of this lethal bacteria. Recent insights into the structure and function of these toxins have increased the understanding of both the pathogenesis and treatment of anthrax. These are binary type toxins comprised of protective antigen necessary for their cellular uptake and either lethal or edema factors, the toxigenic moieties. Primary cellular receptors for protective antigen have been identified and the processing of the completed toxins clarified. Consistent with the ability of lethal factor to cleave mitogen activated protein kinase kinases, the evidence indicates that an excessive inflammatory response does not contribute to shock with LeTx. Rather, the immunosuppressive effects of LeTx could promote infection; however, direct endothelial dysfunction may have an important role in shock due to LeTx. Recent studies show that edema factor, a potent adenyl cyclase, may have a major role in shock during anthrax and that it may also be immunosuppresive. Therapies under development which target several steps in the cellular uptake and function of these two toxins have been effective in both in vitro and in vivo systems. Understanding how best to apply these agents in combination with conventional treatments should be a goal of future research.
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MESH Headings
- Adenylyl Cyclases/immunology
- Adenylyl Cyclases/metabolism
- Animals
- Anthrax/complications
- Anthrax/drug therapy
- Anthrax/metabolism
- Anthrax Vaccines/therapeutic use
- Antibodies, Monoclonal/therapeutic use
- Antigens, Bacterial/immunology
- Antigens, Bacterial/metabolism
- Bacillus anthracis/immunology
- Bacillus anthracis/metabolism
- Bacillus anthracis/pathogenicity
- Bacterial Toxins/immunology
- Bacterial Toxins/metabolism
- Endothelium, Vascular/microbiology
- Endothelium, Vascular/physiopathology
- Humans
- Receptors, Peptide/metabolism
- Shock, Septic/drug therapy
- Shock, Septic/metabolism
- Shock, Septic/microbiology
- Shock, Septic/physiopathology
- Virulence
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Affiliation(s)
- Yan Li
- National Institutes of Health, Critical Care Medicine Department, Clinical Center, Bethesda, MD 20892, USA
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Svitel J, Boukari H, Van Ryk D, Willson RC, Schuck P. Probing the functional heterogeneity of surface binding sites by analysis of experimental binding traces and the effect of mass transport limitation. Biophys J 2007; 92:1742-58. [PMID: 17158569 PMCID: PMC1796841 DOI: 10.1529/biophysj.106.094615] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2006] [Accepted: 11/16/2006] [Indexed: 11/18/2022] Open
Abstract
Many techniques rely on the binding activity of surface-immobilized proteins, including antibody-based affinity biosensors for the detection of analytes, immunoassays, protein arrays, and surface plasmon resonance biosensors for the study of thermodynamic and kinetic aspects of protein interactions. To study the functional homogeneity of the surface sites and to characterize their binding properties, we have recently proposed a computational tool to determine the distribution of affinity and kinetic rate constants from surface binding progress curves. It is based on modeling the experimentally measured binding signal as a superposition of signals from binding to sites spanning a range of rate and equilibrium constants, with regularization providing the most parsimonious distribution consistent with the data. In the present work, we have expanded the scope of this approach to include a compartment-like transport step, which can describe competitive binding to different surface sites in a zone of depleted analyte close to the sensor surface. This approach addresses a major difficulty in the analysis of surface binding where both transport limitation as well as unknown surface site heterogeneity may be present. In addition to the kinetic binding parameters of the ensemble of surface sites, it can provide estimates for effective transport rate constants. Using antibody-antigen interactions as experimental model systems, we studied the effects of the immobilization matrix and of the analyte flow-rate on the effective transport rate constant. Both were experimentally observed to influence mass transport. The approximate description of mass transport by a compartment model becomes critical when applied to strongly transport-controlled data, and we examined the limitations of this model. In the presence of only moderate mass transport limitation the compartment model provides a good description, but this approximation breaks down for strongly transport-limited surface binding. In the latter regime, we report experimental evidence for the formation of gradients within the sensing volume of the evanescent field biosensor used.
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Affiliation(s)
- Juraj Svitel
- National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland, USA
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