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Mechaly A, Diamant E, Alcalay R, Ben David A, Dor E, Torgeman A, Barnea A, Girshengorn M, Levin L, Epstein E, Tennenhouse A, Fleishman SJ, Zichel R, Mazor O. Highly Specific Monoclonal Antibody Targeting the Botulinum Neurotoxin Type E Exposed SNAP-25 Neoepitope. Antibodies (Basel) 2022; 11:21. [PMID: 35323195 PMCID: PMC8944829 DOI: 10.3390/antib11010021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/07/2022] [Accepted: 03/13/2022] [Indexed: 12/31/2022] Open
Abstract
Botulinum neurotoxin type E (BoNT/E), the fastest acting toxin of all BoNTs, cleaves the 25 kDa synaptosomal-associated protein (SNAP-25) in motor neurons, leading to flaccid paralysis. The specific detection and quantification of the BoNT/E-cleaved SNAP-25 neoepitope can facilitate the development of cell-based assays for the characterization of anti-BoNT/E antibody preparations. In order to isolate highly specific monoclonal antibodies suitable for the in vitro immuno-detection of the exposed neoepitope, mice and rabbits were immunized with an eight amino acid peptide composed of the C-terminus of the cleaved SNAP-25. The immunized rabbits developed a specific and robust polyclonal antibody response, whereas the immunized mice mostly demonstrated a weak antibody response that could not discriminate between the two forms of SNAP-25. An immune scFv phage-display library was constructed from the immunized rabbits and a panel of antibodies was isolated. The sequence alignment of the isolated clones revealed high similarity between both heavy and light chains with exceptionally short HCDR3 sequences. A chimeric scFv-Fc antibody was further expressed and characterized, exhibiting a selective, ultra-high affinity (pM) towards the SNAP-25 neoepitope. Moreover, this antibody enabled the sensitive detection of cleaved SNAP-25 in BoNT/E treated SiMa cells with no cross reactivity with the intact SNAP-25. Thus, by applying an immunization and selection procedure, we have isolated a novel, specific and high-affinity antibody against the BoNT/E-derived SNAP-25 neoepitope. This novel antibody can be applied in in vitro assays that determine the potency of antitoxin preparations and reduce the use of laboratory animals for these purposes.
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Affiliation(s)
- Adva Mechaly
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona 7410001, Israel;
| | - Eran Diamant
- Department of Biotechnology, Israel Institute for Biological Research, Ness-Ziona 7410001, Israel; (E.D.); (A.B.D.); (E.D.); (A.T.); (A.B.); (M.G.); (L.L.); (E.E.); (R.Z.)
| | - Ron Alcalay
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona 7410001, Israel;
| | - Alon Ben David
- Department of Biotechnology, Israel Institute for Biological Research, Ness-Ziona 7410001, Israel; (E.D.); (A.B.D.); (E.D.); (A.T.); (A.B.); (M.G.); (L.L.); (E.E.); (R.Z.)
| | - Eyal Dor
- Department of Biotechnology, Israel Institute for Biological Research, Ness-Ziona 7410001, Israel; (E.D.); (A.B.D.); (E.D.); (A.T.); (A.B.); (M.G.); (L.L.); (E.E.); (R.Z.)
| | - Amram Torgeman
- Department of Biotechnology, Israel Institute for Biological Research, Ness-Ziona 7410001, Israel; (E.D.); (A.B.D.); (E.D.); (A.T.); (A.B.); (M.G.); (L.L.); (E.E.); (R.Z.)
| | - Ada Barnea
- Department of Biotechnology, Israel Institute for Biological Research, Ness-Ziona 7410001, Israel; (E.D.); (A.B.D.); (E.D.); (A.T.); (A.B.); (M.G.); (L.L.); (E.E.); (R.Z.)
| | - Meni Girshengorn
- Department of Biotechnology, Israel Institute for Biological Research, Ness-Ziona 7410001, Israel; (E.D.); (A.B.D.); (E.D.); (A.T.); (A.B.); (M.G.); (L.L.); (E.E.); (R.Z.)
| | - Lilach Levin
- Department of Biotechnology, Israel Institute for Biological Research, Ness-Ziona 7410001, Israel; (E.D.); (A.B.D.); (E.D.); (A.T.); (A.B.); (M.G.); (L.L.); (E.E.); (R.Z.)
| | - Eyal Epstein
- Department of Biotechnology, Israel Institute for Biological Research, Ness-Ziona 7410001, Israel; (E.D.); (A.B.D.); (E.D.); (A.T.); (A.B.); (M.G.); (L.L.); (E.E.); (R.Z.)
| | - Ariel Tennenhouse
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7600001, Israel; (A.T.); (S.J.F.)
| | - Sarel J. Fleishman
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7600001, Israel; (A.T.); (S.J.F.)
| | - Ran Zichel
- Department of Biotechnology, Israel Institute for Biological Research, Ness-Ziona 7410001, Israel; (E.D.); (A.B.D.); (E.D.); (A.T.); (A.B.); (M.G.); (L.L.); (E.E.); (R.Z.)
| | - Ohad Mazor
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona 7410001, Israel;
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Li Z, Xu H, Ma B, Luo L, Guo L, Zhang P, Zhao Y, Wang L, Xie J. Neutralizing Monoclonal Antibody, mAb 10D8, Is an Effective Detoxicant against Abrin-a Both In Vitro and In Vivo. Toxins (Basel) 2022; 14:toxins14030164. [PMID: 35324661 PMCID: PMC8955035 DOI: 10.3390/toxins14030164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/17/2022] [Accepted: 02/21/2022] [Indexed: 02/05/2023] Open
Abstract
Abrin is a types II ribosome-inactivating protein (RIP) isolated from Abrus precatorious seeds, which comprises a catalytically active A chain and a lectin-like B chain linked by a disulfide bond. Four isotoxins of abrin have been reported with similar amino-acid composition but different cytotoxicity, of which abrin-a is the most potent toxin. High lethality and easy availability make abrin a potential bioterrorism agent. However, there are no antidotes available for managing abrin poisoning, and treatment is only symptomatic. Currently, neutralizing antibodies remain the most effective therapy against biotoxin poisoning. In this study, we prepared, identified, and acquired a high-affinity neutralizing monoclonal antibody (mAb) 10D8 with a potent pre- and post-exposure protective effect against cytotoxicity and animal toxicity induced by abrin-a or abrin crude extract. The mAb 10D8 could rescue the mouse injected intraperitoneally with a 25 × LD50 dose of abrin-a from lethality and prevent tissue damages. Results indicated that 10D8 does not prevent the binding and internalization of abrin-a to cells but inhibits the enzymatic activity of abrin-a and reduces protein synthesis inhibition of cells. The high affinity, good specificity, and potent antitoxic efficiency of 10D8 make it a promising candidate for therapeutic antibodies against abrin.
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Affiliation(s)
- Zhi Li
- State Key Laboratory of Toxicology and Medical Countermeasures, Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China; (Z.L.); (B.M.); (L.L.); (L.G.); (L.W.)
| | - Hua Xu
- State Key Laboratory of Toxicology and Medical Countermeasures, Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China; (Z.L.); (B.M.); (L.L.); (L.G.); (L.W.)
- Correspondence: (H.X.); (J.X.); Tel.: +86-10-66930621 (H.X.); +86-10-68225893 (J.X.)
| | - Bo Ma
- State Key Laboratory of Toxicology and Medical Countermeasures, Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China; (Z.L.); (B.M.); (L.L.); (L.G.); (L.W.)
| | - Li Luo
- State Key Laboratory of Toxicology and Medical Countermeasures, Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China; (Z.L.); (B.M.); (L.L.); (L.G.); (L.W.)
| | - Lei Guo
- State Key Laboratory of Toxicology and Medical Countermeasures, Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China; (Z.L.); (B.M.); (L.L.); (L.G.); (L.W.)
| | - Pingping Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Key Laboratory of POCT for Bioemergency and Clinic, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China; (P.Z.); (Y.Z.)
| | - Yong Zhao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Key Laboratory of POCT for Bioemergency and Clinic, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China; (P.Z.); (Y.Z.)
| | - Lili Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China; (Z.L.); (B.M.); (L.L.); (L.G.); (L.W.)
| | - Jianwei Xie
- State Key Laboratory of Toxicology and Medical Countermeasures, Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China; (Z.L.); (B.M.); (L.L.); (L.G.); (L.W.)
- Correspondence: (H.X.); (J.X.); Tel.: +86-10-66930621 (H.X.); +86-10-68225893 (J.X.)
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3
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Peng J, Wu J, Shi N, Xu H, Luo L, Wang J, Li X, Xiao H, Feng J, Li X, Chai L, Qiao C. A Novel Humanized Anti-Abrin A Chain Antibody Inhibits Abrin Toxicity In Vitro and In Vivo. Front Immunol 2022; 13:831536. [PMID: 35185923 PMCID: PMC8855095 DOI: 10.3389/fimmu.2022.831536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 01/11/2022] [Indexed: 11/13/2022] Open
Abstract
Abrin, a type-II ribosome inactivating protein from the seed of Abrus precatorius, is classified as a Category B bioterrorism warfare agent. Due to its high toxicity, ingestion by animals or humans will lead to death from multiple organ failure. Currently, no effective agents have been reported to treat abrin poisoning. In this study, a novel anti-abrin neutralizing antibody (S008) was humanized using computer-aided design, which possessed lower immunogenicity. Similar to the parent antibody, a mouse anti-abrin monoclonal antibody, S008 possessed high affinity and showed a protective effect against abrin both in vitro and in vivo, and protected mice that S008 was administered 6 hours after abrin. S008 was found that it did not inhibit entry of abrin into cells, suggesting an intracellular blockade capacity against the toxin. In conclusion, this work demonstrates that S008 is a high affinity anti-abrin antibody with both a neutralizing and protective effect and may be an excellent candidate for clinical treatment of abrin poisoning.
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Affiliation(s)
- Jingyi Peng
- Joint National Laboratory for Antibody Drug Engineering, The First Affiliated Hospital, School of Medicine, Henan University, Kaifeng, China
- State key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Jiaguo Wu
- State key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
- Department of Anatomy, School of Basic Medical Sciences of Dali University, Dali, China
| | - Ning Shi
- State key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
- Cancer Research Institute, School of Basic Medical Science, Central South University, Changsha, China
| | - Hua Xu
- State key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Longlong Luo
- State key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Jing Wang
- State key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Xinying Li
- State key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - He Xiao
- State key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Jiannan Feng
- State key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Xia Li
- Joint National Laboratory for Antibody Drug Engineering, The First Affiliated Hospital, School of Medicine, Henan University, Kaifeng, China
| | - Lihui Chai
- Joint National Laboratory for Antibody Drug Engineering, The First Affiliated Hospital, School of Medicine, Henan University, Kaifeng, China
- *Correspondence: Lihui Chai, ; Chunxia Qiao,
| | - Chunxia Qiao
- State key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
- School of Pharmacy, Henan University, Kaifeng, China
- *Correspondence: Lihui Chai, ; Chunxia Qiao,
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4
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Worbs S, Kampa B, Skiba M, Hansbauer EM, Stern D, Volland H, Becher F, Simon S, Dorner MB, Dorner BG. Differentiation, Quantification and Identification of Abrin and Abrus precatorius Agglutinin. Toxins (Basel) 2021; 13:toxins13040284. [PMID: 33919561 PMCID: PMC8073929 DOI: 10.3390/toxins13040284] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 04/10/2021] [Accepted: 04/13/2021] [Indexed: 12/21/2022] Open
Abstract
Abrin, the toxic lectin from the rosary pea plant Abrus precatorius, has gained considerable interest in the recent past due to its potential malevolent use. However, reliable and easy-to-use assays for the detection and discrimination of abrin from related plant proteins such as Abrus precatorius agglutinin or the homologous toxin ricin from Ricinus communis are sparse. To address this gap, a panel of highly specific monoclonal antibodies was generated against abrin and the related Abrus precatorius agglutinin. These antibodies were used to establish two sandwich ELISAs to preferentially detect abrin or A. precatorius agglutinin (limit of detection 22 pg/mL for abrin; 35 pg/mL for A. precatorius agglutinin). Furthermore, an abrin-specific lateral flow assay was developed for rapid on-site detection (limit of detection ~1 ng/mL abrin). Assays were validated for complex food, environmental and clinical matrices illustrating broad applicability in different threat scenarios. Additionally, the antibodies turned out to be suitable for immuno-enrichment strategies in combination with mass spectrometry-based approaches for unambiguous identification. Finally, we were able to demonstrate for the first time how the developed assays can be applied to detect, identify and quantify abrin from a clinical sample derived from an attempted suicide case involving A. precatorius.
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Affiliation(s)
- Sylvia Worbs
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany; (S.W.); (B.K.); (M.S.); (E.-M.H.); (D.S.); (M.B.D.)
| | - Bettina Kampa
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany; (S.W.); (B.K.); (M.S.); (E.-M.H.); (D.S.); (M.B.D.)
| | - Martin Skiba
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany; (S.W.); (B.K.); (M.S.); (E.-M.H.); (D.S.); (M.B.D.)
| | - Eva-Maria Hansbauer
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany; (S.W.); (B.K.); (M.S.); (E.-M.H.); (D.S.); (M.B.D.)
- Département Médicaments et Technologies pour la Santé, Université Paris Saclay, CEA, INRAE, SPI, 91191 Gif-sur-Yvette, France; (H.V.); (F.B.); (S.S.)
| | - Daniel Stern
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany; (S.W.); (B.K.); (M.S.); (E.-M.H.); (D.S.); (M.B.D.)
| | - Hervé Volland
- Département Médicaments et Technologies pour la Santé, Université Paris Saclay, CEA, INRAE, SPI, 91191 Gif-sur-Yvette, France; (H.V.); (F.B.); (S.S.)
| | - François Becher
- Département Médicaments et Technologies pour la Santé, Université Paris Saclay, CEA, INRAE, SPI, 91191 Gif-sur-Yvette, France; (H.V.); (F.B.); (S.S.)
| | - Stéphanie Simon
- Département Médicaments et Technologies pour la Santé, Université Paris Saclay, CEA, INRAE, SPI, 91191 Gif-sur-Yvette, France; (H.V.); (F.B.); (S.S.)
| | - Martin B. Dorner
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany; (S.W.); (B.K.); (M.S.); (E.-M.H.); (D.S.); (M.B.D.)
| | - Brigitte G. Dorner
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany; (S.W.); (B.K.); (M.S.); (E.-M.H.); (D.S.); (M.B.D.)
- Correspondence: ; Tel.: +49-30-18754-2500
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Makdasi E, Levy Y, Alcalay R, Noy-Porat T, Zahavy E, Mechaly A, Epstein E, Peretz E, Cohen H, Bar-On L, Chitlaru T, Cohen O, Glinert I, Achdout H, Israely T, Rosenfeld R, Mazor O. Neutralizing Monoclonal Anti-SARS-CoV-2 Antibodies Isolated from Immunized Rabbits Define Novel Vulnerable Spike-Protein Epitope. Viruses 2021; 13:566. [PMID: 33810465 PMCID: PMC8065470 DOI: 10.3390/v13040566] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/19/2021] [Accepted: 03/24/2021] [Indexed: 12/23/2022] Open
Abstract
Monoclonal antibodies represent an important avenue for COVID-19 therapy and are routinely used for rapid and accessible diagnosis of SARS-CoV-2 infection. The recent emergence of SARS-CoV-2 genetic variants emphasized the need to enlarge the repertoire of antibodies that target diverse epitopes, the combination of which may improve immune-diagnostics, augment the efficiency of the immunotherapy and prevent selection of escape-mutants. Antigen-specific controlled immunization of experimental animals may elicit antibody repertoires that significantly differ from those generated in the context of the immune response mounted in the course of disease. Accordingly, rabbits were immunized by several recombinant antigens representing distinct domains of the viral spike protein and monoclonal antibodies were isolated from single cells obtained by cell sorting. Characterization of a panel of successfully isolated anti-receptor binding domain (RBD) and anti-N-terminal domain (NTD) antibodies demonstrated that they exhibit high specificity and affinity profiles. Anti-RBD antibodies revealing significant neutralizing potency against SARS-CoV-2 in vitro were found to target at least three distinct epitopes. Epitope mapping established that two of these antibodies recognized a novel epitope located on the surface of the RBD. We suggest that the antibodies isolated in this study are useful for designing SARS-CoV-2 diagnosis and therapy approaches.
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Epitope Binning of Novel Monoclonal Anti F1 and Anti LcrV Antibodies and Their Application in a Simple, Short, HTRF Test for Clinical Plague Detection. Pathogens 2021; 10:pathogens10030285. [PMID: 33801490 PMCID: PMC8001648 DOI: 10.3390/pathogens10030285] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 11/18/2022] Open
Abstract
Mouse monoclonal antibodies were raised against plague disease biomarkers: the bacterial capsular protein fraction 1 (F1) and the low-calcium response—LcrV virulence factor (Vag). A novel tandem assay, employing BioLayer Interferometry (BLI), enabled the isolation of antibodies against four different epitopes on Vag. The tandem assay was carried out with hybridoma supernatants, circumventing the need for antibody purification. The BioLayer assay was further adopted for characterization of epitope-repetitive antigens, enabling the discovery of two unique epitopes on F1. The selected antibodies were purified and applied as “oligo-clonal” reagents for the immuno-detection of both biomarkers. The developed Homogenous Time Resolved Fluorescence (HTRF) tests were short (10 min) and simple (no washing steps), allowing for detection of 10 ng/mL F1 and 2.5 ng/mL Vag. The tests were successfully applied for detection of disease biomarkers produced by various Y. pestis strains during growth in blood culture vials.
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Alcalay R, Falach R, Gal Y, Sapoznikov A, Sabo T, Kronman C, Mazor O. Mapping Immunodominant Antibody Epitopes of Abrin. Antibodies (Basel) 2020; 9:antib9020011. [PMID: 32349421 PMCID: PMC7344891 DOI: 10.3390/antib9020011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 04/21/2020] [Accepted: 04/22/2020] [Indexed: 11/22/2022] Open
Abstract
Abrin, a toxin isolated from the seeds of Abrus precatorius (jequirity pea) is considered a biological threat agent by the Center for Disease Control and Prevention. To date, there is no effective postexposure treatment for abrin poisoning, and efforts are being made to develop an efficient vaccine and measures for postexposure therapy. Epitope mapping is widely applied as an efficient tool for discovering the antigenic moieties of toxins, thus providing invaluable information needed for the development of vaccines and therapies. Aiming to identify the immunodominant epitopes of abrin, several neutralizing antiabrin polyclonal antibodies were screened using a set of 15-mer peptides spanning the amino acid sequence of either the A or B subunits of abrin. Analysis of the antibody-binding pattern revealed 11 linear epitopes for the A subunit and 14 epitopes for the B subunit that are located on the surface of the toxin and thus accessible for antibody interactions. Moreover, the spatial location of several of these epitopes suggests they may block the galactose-binding pockets or the catalytic domain, thus neutralizing the toxin. These findings provide useful information and suggest a possible strategy for the development and design of an improved abrin-based vaccine and therapeutic antibodies.
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Affiliation(s)
- Ron Alcalay
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona 76100, Israel; (R.A.); (R.F.); (Y.G.); (A.S.); (T.S.); (C.K.)
| | - Reut Falach
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona 76100, Israel; (R.A.); (R.F.); (Y.G.); (A.S.); (T.S.); (C.K.)
| | - Yoav Gal
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona 76100, Israel; (R.A.); (R.F.); (Y.G.); (A.S.); (T.S.); (C.K.)
| | - Anita Sapoznikov
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona 76100, Israel; (R.A.); (R.F.); (Y.G.); (A.S.); (T.S.); (C.K.)
| | - Tamar Sabo
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona 76100, Israel; (R.A.); (R.F.); (Y.G.); (A.S.); (T.S.); (C.K.)
| | - Chanoch Kronman
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona 76100, Israel; (R.A.); (R.F.); (Y.G.); (A.S.); (T.S.); (C.K.)
| | - Ohad Mazor
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona 76100, Israel
- Correspondence: ; Tel.: +972-8-9385862; Fax: +972-8-9381544
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Equal Neutralization Potency of Antibodies Raised against Abrin Subunits. Antibodies (Basel) 2020; 9:antib9010004. [PMID: 32041179 PMCID: PMC7148520 DOI: 10.3390/antib9010004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 01/22/2020] [Accepted: 01/25/2020] [Indexed: 11/17/2022] Open
Abstract
Abrin and ricin are potent AB toxins, which are considered biological threats. To date, there are no approved treatments against abrin or ricin intoxications. Previously, we showed that the administration of polyclonal anti-abrin antibodies to mice that were intranasally exposed to abrin, even very late post-exposure, conferred an exceedingly high-level of protection, while following ricin intoxication, similar treatment with anti-ricin antibodies resulted in negligible survival rates. To probe this unexpected difference in protection ability, we first examined whether the efficient anti-abrin-induced protection was due to neutralization of the A-subunit responsible for the catalytic effect, or of the B-subunit, which enables binding/internalization, by evaluating the protection conferred by antibodies directed against one of the two subunits. To this end, we generated and immunized rabbits with chimeric toxins containing a single abrin subunit, AabrinBricin in which abrin A-subunit was linked to ricin B-subunit, and AricinBabrin in which ricin A-subunit is linked to abrin B-subunit. Here, we show that antibodies raised against either AabrinBricin or AricinBabrin conferred exceptionally high protection levels to mice following intranasal exposure to a a lethal dose of abrin, suggesting that the high level of protection conferred by anti-abrin antibodies is not related to the neutralization of a particular subunit.
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Inhibition of Francisella tularensis phagocytosis using a novel anti-LPS scFv antibody fragment. Sci Rep 2019; 9:11418. [PMID: 31388083 PMCID: PMC6684794 DOI: 10.1038/s41598-019-47931-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 07/25/2019] [Indexed: 12/23/2022] Open
Abstract
Francisella tularensis (Ft), the causative agent of lethal tularemia, is classified as a category A biological warfare threat agent. While Ft infection is treatable by antibiotics, many failed antibiotic treatments were reported, highlighting the need for effective new treatments. It has been demonstrated that binding of antibody-coated bacteria to the Fc receptor located on phagocytic cells is a key process needed for efficient protection against Ft. Yet, Ft utilizes the same receptor to enter the phagocytic cells in order to escape the immune system. To address the question whether an anti-Ft LPS antibody lacking the ability to bind the Fc receptor may inhibit the entry of Ft into host cells, a soluble scFv (TL1-scFv) was constructed from an anti Ft-LPS antibody (TL1) that was isolated from an immune single-chain (scFv) phage-display library. Bacterial uptake was assessed upon infection of macrophages with Ft live attenuated strain (LVS) in the presence of either TL1 or TL1-scFv. While incubation of LVS in the presence of TL1 greatly enhanced bacterial uptake, LVS uptake was significantly inhibited in the presence of TL1-scFv. These results prompt further experiments probing the therapeutic efficacy of TL1-scFv, alone or in combination with antibiotic treatment.
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Xu Y, Li P, Nie J, Zhao Q, Guan S, Kuai Z, Qiao Y, Jiang X, Li Y, Li W, Shi Y, Kong W, Shan Y. Humanization and directed evolution of the selenium-containing scFv phage abzyme. RSC Adv 2018; 8:17218-17223. [PMID: 35539266 PMCID: PMC9080455 DOI: 10.1039/c8ra02798f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 05/03/2018] [Indexed: 12/22/2022] Open
Abstract
According to the binding site structure and the catalytic mechanism of the native glutathione peroxidase (GPX), three glutathione derivatives, GSH-S-DNP butyl ester (hapten Be), GSH-S-DNP hexyl ester (hapten He) and GSH-S-DNP hexamethylene ester (hapten Hme) were synthesized. By a four-round panning with a human synthetic scFv phage library against three haptens, the enrichment of the scFv phage particles with specific binding activity could be determined. Three phage particles were selected binding to each glutathione derivative, respectively. After a two-step chemical mutation to convert the serine residues of the scFv phage particles into selenocysteine residues, GPX activity could be observed and determined upto 3000 U μmol-1 in the selenium-containing scFv phage abzyme which was isolated by affinity capture against the hapten Be. Also the scFv phage abzymes elicited by different antigens displayed different catalytic activities. After a directed evolution by DNA shuffling to improve the affinity to the hapten Be, a secondary library with GPX activity was created in which the catalytic activity of the selenium-containing scFv phage abzyme could be increased 17%. This study might be helpful for new haptens or antigens design to optimize the abzymes with high binding activities and might also provide a novel scheme for GPX mimic candidates for drug development.
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Affiliation(s)
- Yan Xu
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University Changchun Jilin China +86 431 85167751 +86 431 89228979
| | - Pengju Li
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University Changchun Jilin China +86 431 85167751 +86 431 89228979
| | - Jiaojiao Nie
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University Changchun Jilin China +86 431 85167751 +86 431 89228979
| | - Qi Zhao
- Faculty of Health Sciences, University of Macau Macau China
| | - Shanshan Guan
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University Changchun Jilin China +86 431 85167751 +86 431 89228979
| | - Ziyu Kuai
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University Changchun Jilin China +86 431 85167751 +86 431 89228979
| | - Yongbo Qiao
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University Changchun Jilin China +86 431 85167751 +86 431 89228979
| | - Xiaoyu Jiang
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University Changchun Jilin China +86 431 85167751 +86 431 89228979
| | - Ying Li
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University Changchun Jilin China +86 431 85167751 +86 431 89228979
| | - Wei Li
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University Changchun Jilin China +86 431 85167751 +86 431 89228979
| | - Yuhua Shi
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University Changchun Jilin China +86 431 85167751 +86 431 89228979
| | - Wei Kong
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University Changchun Jilin China +86 431 85167751 +86 431 89228979.,Key Laboratory for Molecular Enzymology and Engineering, The Ministry of Education, School of Life Sciences, Jilin University Changchun Jilin China
| | - Yaming Shan
- National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University Changchun Jilin China +86 431 85167751 +86 431 89228979.,Key Laboratory for Molecular Enzymology and Engineering, The Ministry of Education, School of Life Sciences, Jilin University Changchun Jilin China
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