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Hmaidi R, Ksouri A, Benabderrazek R, Antonietti V, Sonnet P, Gautier M, Bouhaouala-Zahar B, Ouadid-Ahidouch H. The Pharmacological and Structural Basis of the AahII–NaV1.5 Interaction and Modulation by the Anti-AahII Nb10 Nanobody. Front Pharmacol 2022; 13:821181. [PMID: 35295326 PMCID: PMC8918821 DOI: 10.3389/fphar.2022.821181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 01/17/2022] [Indexed: 11/13/2022] Open
Abstract
Scorpion α-toxins are neurotoxins that target the fast inactivation mechanism of voltage-gated sodium (NaV) channels leading to several neuro- and cardiotoxic effects in mammals. The toxin AahII is the most active α-toxin from the North African scorpion Androctonus australis Hector that slows the fast inactivation of NaV channels. To fight scorpion envenomation, an anti-AahII nanobody named NbAahII10 (Nb10) was developed. The efficiency of this nanobody has been evaluated in vivo on mice, but its mechanism of action at the cellular level remains unknown. Here we have shown that AahII toxin slows the fast inactivation of the adult cardiac NaV1.5 channels, expressed in HEK293 cells, in a dose-dependent manner, while current amplitude was not affected. The inactivation of NaV1.5 is slower by a factor of 4, 7, and 35 in the presence of [AahII] at 75, 150, and 300 nM, respectively. The washout partially reversed the toxin effect on inactivation from 8.3 ± 0.9 ms to 5.2 ± 1.2 ms at 75 nM. We have also demonstrated that the highly neutralizing Nb10 can fully reverse the effect of AahII toxin on the channel inactivation kinetics even at the 1:1 M ratio. However, the 1:0.5 M ratio is not able to neutralize completely the AahII effect. Therefore, the application of Nb10 promotes a partial abolishment of AahII action. Bioinformatic analysis and prediction of NaV1.5-driven docking with AahII show that Ala39 and Arg62 of AahII play a crucial role to establish a stable interaction through H-bound interactions with Gln1615 and Lys1616 (S3–S4 extracellular loop) and Asp1553 (S1–S2 loop) from the voltage-sensing domain IV (VSD4) of NaV1.5, respectively. From this, we notice that AahII shares the same contact surface with Nb10. This strongly suggests that Nb10 dynamically replaces AahII toxin from its binding site on the NaV1.5 channel. At the physiopathological level, Nb10 completely neutralized the enhancement of breast cancer cell invasion induced by AahII. In summary, for the first time, we made an electrophysiological and structural characterization of the neutralization potent of Nb10 against the α-scorpion toxin AahII in a cellular model overexpressing NaV1.5 channels.
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Affiliation(s)
- Riadh Hmaidi
- Laboratory of Biomolecules, Venoms, and Theranostic Applications, Institut Pasteur Tunis, University of Tunis El Manar, Tunis, Tunisia
- Laboratory of Cellular and Molecular Physiology UR 4667, UFR of Sciences, University of Picardie Jules Verne, Amiens, France
| | - Ayoub Ksouri
- Laboratory of Biomolecules, Venoms, and Theranostic Applications, Institut Pasteur Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Rahma Benabderrazek
- Laboratory of Biomolecules, Venoms, and Theranostic Applications, Institut Pasteur Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Viviane Antonietti
- Infectious Agents, Resistance and Chemotherapy UR 4294, UFR of Pharmacy, University of Picardie Jules Verne, Amiens, France
| | - Pascal Sonnet
- Infectious Agents, Resistance and Chemotherapy UR 4294, UFR of Pharmacy, University of Picardie Jules Verne, Amiens, France
| | - Mathieu Gautier
- Laboratory of Cellular and Molecular Physiology UR 4667, UFR of Sciences, University of Picardie Jules Verne, Amiens, France
- *Correspondence: Mathieu Gautier, ; Balkiss Bouhaouala-Zahar, ; Halima Ouadid-Ahidouch,
| | - Balkiss Bouhaouala-Zahar
- Laboratory of Biomolecules, Venoms, and Theranostic Applications, Institut Pasteur Tunis, University of Tunis El Manar, Tunis, Tunisia
- Medical School of Tunis, University of Tunis El Manar, Tunis, Tunisia
- *Correspondence: Mathieu Gautier, ; Balkiss Bouhaouala-Zahar, ; Halima Ouadid-Ahidouch,
| | - Halima Ouadid-Ahidouch
- Laboratory of Cellular and Molecular Physiology UR 4667, UFR of Sciences, University of Picardie Jules Verne, Amiens, France
- *Correspondence: Mathieu Gautier, ; Balkiss Bouhaouala-Zahar, ; Halima Ouadid-Ahidouch,
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Synthetic peptides to produce antivenoms against the Cys-rich toxins of arachnids. Toxicon X 2020; 6:100038. [PMID: 32550593 PMCID: PMC7285918 DOI: 10.1016/j.toxcx.2020.100038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 04/15/2020] [Accepted: 04/24/2020] [Indexed: 12/15/2022] Open
Abstract
Scorpion and spider envenomation is treated with the appropriate antivenoms, prepared as described by Césaire Auguste Phisalix and Albert Calmette in 1894. Such treatment requires the acquisition and manipulation of arachnid venoms, both very complicated procedures. Most of the toxins in the venoms of spiders and scorpions are extremely stable cysteine-rich peptide neurotoxins. Many strategies have been developed to obtain synthetic immunogens to facilitate the production of antivenoms against these toxins. For example, whole peptide toxins can be synthesized by solid-phase peptide synthesis (SPPS). Also, epitopes of the toxins can be identified and after the chemical synthesis of these peptide epitopes by SPPS, they can be coupled to protein carriers to develop efficient immunogens. Moreover, multiple antigenic peptides with a polylysine core can be designed and synthesized. This review focuses on the strategies developed to obtain synthetic immunogens for the production of antivenoms against the toxic Cys-rich peptides of scorpions and spiders.
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Martin-Eauclaire MF, Adi-Bessalem S, Hammoudi-Triki D, Laraba-Djebari F, Bougis PE. Serotherapy against Voltage-Gated Sodium Channel-Targeting αToxins from Androctonus Scorpion Venom. Toxins (Basel) 2019; 11:toxins11020063. [PMID: 30678116 PMCID: PMC6410273 DOI: 10.3390/toxins11020063] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/18/2019] [Accepted: 01/21/2019] [Indexed: 12/12/2022] Open
Abstract
Because of their venom lethality towards mammals, scorpions of the Androctonus genus are considered a critical threat to human health in North Africa. Several decades of exploration have led to a comprehensive inventory of their venom components at chemical, pharmacological, and immunological levels. Typically, these venoms contain selective and high affinity ligands for the voltage-gated sodium (Nav) and potassium (Kv) channels that dictate cellular excitability. In the well-studied Androctonus australis and Androctonus mauretanicus venoms, almost all the lethality in mammals is due to the so-called α-toxins. These peptides commonly delay the fast inactivation process of Nav channels, which leads to increased sodium entry and a subsequent cell membrane depolarization. Markedly, their neutralization by specific antisera has been shown to completely inhibit the venom’s lethal activity, because they are not only the most abundant venom peptide but also the most fatal. However, the structural and antigenic polymorphisms in the α-toxin family pose challenges to the design of efficient serotherapies. In this review, we discuss past and present accomplishments to improve serotherapy against Androctonus scorpion stings.
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Affiliation(s)
| | - Sonia Adi-Bessalem
- Laboratory of Cellular and Molecular Biology, Faculty of Biological Sciences, USTHB, BP 32, El-Alia Bab Ezzouar, 16111 Algiers, Algeria.
| | - Djelila Hammoudi-Triki
- Laboratory of Cellular and Molecular Biology, Faculty of Biological Sciences, USTHB, BP 32, El-Alia Bab Ezzouar, 16111 Algiers, Algeria.
| | - Fatima Laraba-Djebari
- Laboratory of Cellular and Molecular Biology, Faculty of Biological Sciences, USTHB, BP 32, El-Alia Bab Ezzouar, 16111 Algiers, Algeria.
| | - Pierre E Bougis
- Laboratory of Cognitive Neuroscience, CNRS, Aix Marseille Univ, UMR 7291, 13003 Marseille, France.
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Bermúdez-Méndez E, Fuglsang-Madsen A, Føns S, Lomonte B, Gutiérrez JM, Laustsen AH. Innovative Immunization Strategies for Antivenom Development. Toxins (Basel) 2018; 10:toxins10110452. [PMID: 30400220 PMCID: PMC6265855 DOI: 10.3390/toxins10110452] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 10/29/2018] [Accepted: 10/30/2018] [Indexed: 12/13/2022] Open
Abstract
Snakes, scorpions, and spiders are venomous animals that pose a threat to human health, and severe envenomings from the bites or stings of these animals must be treated with antivenom. Current antivenoms are based on plasma-derived immunoglobulins or immunoglobulin fragments from hyper-immunized animals. Although these medicines have been life-saving for more than 120 years, opportunities to improve envenoming therapy exist. In the later decades, new biotechnological tools have been applied with the aim of improving the efficacy, safety, and affordability of antivenoms. Within the avenues explored, novel immunization strategies using synthetic peptide epitopes, recombinant toxins (or toxoids), or DNA strings as immunogens have demonstrated potential for generating antivenoms with high therapeutic antibody titers and broad neutralizing capacity. Furthermore, these approaches circumvent the need for venom in the production process of antivenoms, thereby limiting some of the complications associated with animal captivity and venom collection. Finally, an important benefit of innovative immunization approaches is that they are often compatible with existing antivenom manufacturing setups. In this review, we compile all reported studies examining venom-independent innovative immunization strategies for antivenom development. In addition, a brief description of toxin families of medical relevance found in snake, scorpion, and spider venoms is presented, as well as how biochemical, bioinformatic, and omics tools could aid the development of next-generation antivenoms.
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Affiliation(s)
| | - Albert Fuglsang-Madsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
- Department of Biology, University of Copenhagen, DK-2200 København N, Denmark.
| | - Sofie Føns
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
| | - Bruno Lomonte
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501-2060, Costa Rica.
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501-2060, Costa Rica.
| | - Andreas Hougaard Laustsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
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Ksouri A, Ghedira K, Ben Abderrazek R, Shankar BG, Benkahla A, Bishop OT, Bouhaouala-Zahar B. Homology modeling and docking of AahII-Nanobody complexes reveal the epitope binding site on AahII scorpion toxin. Biochem Biophys Res Commun 2018; 496:1025-1032. [DOI: 10.1016/j.bbrc.2018.01.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 01/04/2018] [Indexed: 11/25/2022]
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Fabrichny IP, Mondielli G, Conrod S, Martin-Eauclaire MF, Bourne Y, Marchot P. Structural insights into antibody sequestering and neutralizing of Na+ channel α-type modulator from old world scorpion venom. J Biol Chem 2012; 287:14136-48. [PMID: 22371498 DOI: 10.1074/jbc.m111.315382] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The Old World scorpion Androctonus australis hector (Aah) produces one of the most lethal venoms for humans. Peptidic α-toxins AahI to AahIV are responsible for its potency, with AahII accounting for half of it. All four toxins are high affinity blockers of the fast inactivation phase of mammalian voltage-activated Na(+) channels. However, the high antigenic polymorphism of α-toxins prevents production of a polyvalent neutralizing antiserum, whereas the determinants dictating their trapping by neutralizing antibodies remain elusive. From an anti-AahII mAb, we generated an antigen binding fragment (Fab) with high affinity and selectivity for AahII and solved a 2.3 Å-resolution crystal structure of the complex. Sequestering of the C-terminal region of the bound toxin within a groove formed by the Fab combining loops is associated with a toxin orientation and main and side chain conformations that dictate the AahII antigenic specificity and efficient neutralization. From an anti-AahI mAb, we also preformed and crystallized a high affinity AahI-Fab complex. The 1.6 Å-resolution structure solved revealed a Fab molecule devoid of a bound AahI and with combining loops involved in packing interactions, denoting expulsion of the bound antigen upon crystal formation. Comparative analysis of the groove-like combining site of the toxin-bound anti-AahII Fab and planar combining surface of the unbound anti-AahI Fab along with complementary data from a flexible docking approach suggests occurrence of distinctive trapping orientations for the two toxins relative to their respective Fab. This study provides complementary templates for designing new molecules aimed at capturing Aah α-toxins and suitable for immunotherapy.
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Affiliation(s)
- Igor P Fabrichny
- Faculté de Médecine Secteur Nord, Centre de Recherche en Neurobiologie-Neurophysiologie de Marseille, CRN2M, CNRS/Aix-Marseille Université UMR-6231, Institut Fédératif de Recherche Jean Roche, CS80011, F-13344 Marseille cedex 15, France
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Alvarenga L, Moreau V, Felicori L, Nguyen C, Duarte C, Chavez-Olortegui C, Molina F, Martin-Eauclaire MF, Granier C. Design of antibody-reactive peptides from discontinuous parts of scorpion toxins. Vaccine 2010; 28:970-80. [DOI: 10.1016/j.vaccine.2009.10.135] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 10/27/2009] [Accepted: 10/28/2009] [Indexed: 10/20/2022]
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Duarte CG, Alvarenga LM, Dias-Lopes C, Machado-de-Avila RA, Nguyen C, Molina F, Granier C, Chávez-Olórtegui C. In vivo protection against Tityus serrulatus scorpion venom by antibodies raised against a discontinuous synthetic epitope. Vaccine 2009; 28:1168-76. [PMID: 19948263 DOI: 10.1016/j.vaccine.2009.11.039] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Revised: 11/06/2009] [Accepted: 11/11/2009] [Indexed: 11/16/2022]
Abstract
Scorpion stings cause human fatalities in numerous countries. Serotherapy is the only specific means to try to circumvent the noxious effects of venom toxins. TsNTxP is a natural anatoxin from the venom of the scorpion Tityus serrulatus that may be useful to raise therapeutic anti-venom sera. Linear epitopes recognized by anti-TsNTxP antibodies have previously been mapped. Here, we attempted to identify discontinuous epitopes in TsNTxP since neutralizing epitopes are often associated with such complex entities. One hundred and fifty-three octadecapeptides with the general formula (P1)-(Gly-Gly)-(P2) were synthesized by the Spot method on cellulose membranes. P1 and P2 were octapeptides from the TsNTxP N-terminal and C-terminal sections, respectively. Each sequence of eight amino acids was frameshifted in turn by three residues, in order to cover TsNTxP entire sequence. Binding of neutralizing anti-TsNTxP rabbit antibodies to spotted peptides revealed GREGYPADGGGLPDSVKI as the more reactive peptide sequence. This epitope was made from the first eight residues of the protein (GREGYPAD) and from residues 47 to 54 (GLPDSVKI) of the C-terminal part of TsNTxP. BALB/c mice were immunized with synthetic GREGYPADGGGLPDSVKI peptide conjugated to ovalbumin. One week after the last immunization, in vivo protection assays showed that immunized mice could resist a challenge by an amount of T.serrulatus whole venom equivalent to 1.75 LD(100), a dose that killed all control non-immune mice. Based on molecular models of TsNTxP and related Tityus toxins, we found that the above peptide matches with a discontinuous epitope, well exposed at the toxin molecular surface which contains residues known to be important for the bioactivity of toxins.
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Affiliation(s)
- Clara Guerra Duarte
- Departamentos de Bioquímica-Imunologia, ICB, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, Pampulha, CP 486, CEP 31270901, Belo Horizonte-MG, Brazil
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Larsen JEP, Lund O, Nielsen M. Improved method for predicting linear B-cell epitopes. Immunome Res 2006; 2:2. [PMID: 16635264 PMCID: PMC1479323 DOI: 10.1186/1745-7580-2-2] [Citation(s) in RCA: 817] [Impact Index Per Article: 45.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2006] [Accepted: 04/24/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND B-cell epitopes are the sites of molecules that are recognized by antibodies of the immune system. Knowledge of B-cell epitopes may be used in the design of vaccines and diagnostics tests. It is therefore of interest to develop improved methods for predicting B-cell epitopes. In this paper, we describe an improved method for predicting linear B-cell epitopes. RESULTS In order to do this, three data sets of linear B-cell epitope annotated proteins were constructed. A data set was collected from the literature, another data set was extracted from the AntiJen database and a data sets of epitopes in the proteins of HIV was collected from the Los Alamos HIV database. An unbiased validation of the methods was made by testing on data sets on which they were neither trained nor optimized on. We have measured the performance in a non-parametric way by constructing ROC-curves. CONCLUSION The best single method for predicting linear B-cell epitopes is the hidden Markov model. Combining the hidden Markov model with one of the best propensity scale methods, we obtained the BepiPred method. When tested on the validation data set this method performs significantly better than any of the other methods tested. The server and data sets are publicly available at http://www.cbs.dtu.dk/services/BepiPred.
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Affiliation(s)
- Jens Erik Pontoppidan Larsen
- Center for Biological Sequence Analysis, BioCentrum-DTU, Building 208, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Ole Lund
- Center for Biological Sequence Analysis, BioCentrum-DTU, Building 208, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Morten Nielsen
- Center for Biological Sequence Analysis, BioCentrum-DTU, Building 208, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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Alvarenga LM, Diniz CR, Granier C, Chávez-Olórtegui C. Induction of neutralizing antibodies against Tityus serrulatus scorpion toxins by immunization with a mixture of defined synthetic epitopes. Toxicon 2002; 40:89-95. [PMID: 11602284 DOI: 10.1016/s0041-0101(01)00197-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We have used the Spot method of multiple peptide synthesis to prepare sets of immobilized overlapping peptides of uniform size (15 mer), covering the complete amino acid sequences of TsNTxP a non-toxic and immunogenic protein and TsIV, an alpha-type toxin that is the major lethal component of the venom of scorpion Tityus serrulatus. Anti-TsNTxP antibodies binding to peptides, revealed three antigenic regions, one in the N-terminal, the second in the central part and the other in the C-terminal part of TsNTxP. One peptide epitope in the C-terminal part of TsIV was identified with anti-TsIV neutralizing rabbit antibodies. Anti-peptide antibodies were raised against these four peptides all together covalently coupled to keyhole limpet hemocyanin (KLH) and found to neutralize in vitro the toxic effects of the T. serrulatus venom. Quantities of venom equivalent to 13.5 LD(50) were effectively neutralized by 1ml of the anti-peptide serum. The antigenic specificities of the anti-peptides were compared by an indirect enzyme-linked immunosorbent assay (ELISA) using synthetic peptides and crude venoms from T. serrulatus, T. bahiensis, T. cambridgei, T. stigmurus, Androctonus autralis Hector and Centruroides sculpturatus to coat the microtitration plates. The anti-peptide antibodies had a comparable high reactivity with the crude venom of T. serrulatus, moderate binding to T. bahiensis, T. cambridgei, T. stigmurus and Centruroides sculpturatus venoms but were unable to recognize the venom of Androctonus autralis Hector. These results show that by using peptides derived from the sequence of scorpion toxins, the generation of anti-peptide antibodies able to neutralize the cognate venom appears to be an alternative strategy for the easy preparation of antivenoms.
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Affiliation(s)
- L M Alvarenga
- Fundação Ezequiel Dias, Rua Conde Pereira Carneiro 80, 30550-010, MG, Belo Horizonte, Brazil
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Calderon-Aranda ES, Selisko B, York EJ, Gurrola GB, Stewart JM, Possani LD. Mapping of an epitope recognized by a neutralizing monoclonal antibody specific to toxin Cn2 from the scorpion Centruroides noxius, using discontinuous synthetic peptides. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 264:746-55. [PMID: 10491120 DOI: 10.1046/j.1432-1327.1999.00620.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The Na+-channel-affecting toxin Cn2 represents the major and one of the most toxic components of the venom of the Mexican scorpion Centruroides noxius Hoffmann. A monoclonal antibody BCF2 raised against Cn2 has been shown previously to be able to neutralize the toxic effect of Cn2 and of the whole venom of C. noxius. In the present study the epitope was mapped to a surface region comprising the N- and C-terminal segments of Cn2, using continuous and discontinuous synthetic peptides, designed on the basis of the sequence and a three-dimensional model of Cn2. The study of peptides of varying length resulted in the identification of segments 5-14 and 56-65 containing residues essential for recognition by BCF2. The peptide (abbreviated SP7) with the highest affinity to BCF2 (IC50 = 5.1 microM) was a synthetic heterodimer comprising the amino acid sequence from position 3-15 (amidated) of Cn2, bridged by disulfide to peptide from position 54-66, acetylated and amidated. Similar affinity was found with peptide SP1 [heterodimer comprising residues 1-14 (amidated) of Cn2, bridged with synthetic peptide 52-66 (acetylated)]. SP1 and SP7 were used to induce anti-peptide antibodies in mouse and rabbit. Both peptides were highly immunogenic. The sera obtained were able to recognize Cn2 and to neutralize Cn2 in vitro. The most efficient protection (8.3 microgram Cn2 neutralized per mL of serum) was induced by rabbit anti-SP1 serum.
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Affiliation(s)
- E S Calderon-Aranda
- Department of Molecular Recognition, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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Gomme PT, Stanton PG, Hearn MT. Evaluation of a pepscan approach to identify epitopes recognised by anti-hTSH monoclonal antibodies. JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS 1999; 38:53-70. [PMID: 10078873 DOI: 10.1016/s0165-022x(98)00037-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In this study, several methodological aspects of the pepscan strategy have been investigated with the objective to delineate the amino acid sequences of peptide segments that form the epitopes of thyrotropin beta-subunit (TSHbeta) recognised by monoclonal antibodies. Hitherto, the pepscan strategy has found application as an effective method to identify linear sequence regions that constitute contiguous epitopes within the primary structure of some proteins. However, with heterodimeric glycoprotein hormones and their subunits such as TSHbeta, as well as for many other globular proteins, the majority of the epitopes recognised by anti-protein antibodies will be derived from discontinuous segments that collectively form the epitope. In these cases the pepscan technique will only be able to identify individual segments of the overall discontinuous epitope site as linear peptides, some of which may interact with relatively low binding affinity. Consequently, additional attention must thus be given to the optimisation of the specific binding and detection conditions. Knowledge of the structures of these peptide segments can, however, provide a valuable basis to develop peptide structures that more closely mimic the topographical features of the epitope in the mature, folded protein. In an attempt to identify functional segments involved in the epitopes recognised by the anti-hTSH monoclonal antibodies, mAb279 and mAb299, the impact of various experimental conditions on the efficacy of the pepscan strategy has been investigated. The strategy involved the synthesis of a series of overlapping pin-bound octapeptides with amino acid sequences derived from the TSH beta-subunit. The ability of these pin-bound octapeptides to bind to either mAb279 or mAb299 in ELISA-based assay was then determined under conditions involving different concentrations of the primary and/or secondary antibodies, and changes in buffer composition, incubation times and washing procedures. Theresults of this study illustrate some of the constraints and limitations of the pepscan technique when used to delineate discontinuous epitopes of globular proteins, as well as providing insight into potential avenues to optimise and refine this method.
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Affiliation(s)
- P T Gomme
- Centre for Bioprocess Technology, Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
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Takahashi T, Conforti A, Kikumoto Y, Hoon DS, Morton DL, Irie RF. Augmentation of IgM antibody to gp43 tumor-associated antigen peptide by melanoma cell vaccine. J Clin Immunol 1998; 18:299-305. [PMID: 9710747 DOI: 10.1023/a:1027342024618] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We previously reported that gp43 tumor-associated antigen peptide (DLTMKYQIF; designated 810 antigen) on human melanoma cells is recognized by IgM human monoclonal antibody L92 and by cytotoxic T lymphocytes (CTL). In this study, we retrospectively tested sera of 44 patients with regional metastatic melanoma (22 who recurred within 1 year and 22 who survived longer than 5 years) to determine if antibody responses to 810 antigen could be induced by immunization with an allogeneic melanoma cell vaccine that contained 810 peptide. IgM and IgG antibodies were assessed by enzyme-linked immunosorbent assay using a synthetic 810 nonamer peptide. A significant augmentation of IgM antibody was demonstrated 4 weeks after initiation of vaccine therapy, and the IgM level was significantly higher in patients who survived more than 5 years. The antigen epitope recognized by antibodies was located within TMKYQI. Of this epitope sequence, K appears to play a central role in antigenicity. The 810 antigen recognized by antibody and CTL may have clinical relevance as a potential source of melanoma vaccine.
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Affiliation(s)
- T Takahashi
- Department of Biotechnology Sciences, John Wayne Cancer Institute, Santa Monica, California
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Lecomte C, Sabatier JM, Van Rietschoten J, Rochat H. Synthetic peptides as tools to investigate the structure and pharmacology of potassium channel-acting short-chain scorpion toxins. Biochimie 1998; 80:151-4. [PMID: 9587672 DOI: 10.1016/s0300-9084(98)80021-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In the last decade, numerous polypeptide toxins acting on ion channels have been isolated and characterized from diverse scorpion venoms. These toxins are useful pharmacological probes to study ion-specific channel proteins because they interact selectively with these channels and modulate their activities. Since low amounts of natural toxins can be isolated from scorpion venoms, the chemical synthesis approach is extremely useful to produce larger quantities of toxins and toxin analogs. This report is a succinct overview of the possibilities offered by the chemical synthesis to investigate pharmacological and structural properties of these compounds.
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Affiliation(s)
- C Lecomte
- Laboratoire de Biochimie, Ingéniérie des Protéines, CNRS UMR 6560, IFR Jean Roche, Faculté de Médecine Nord, Marseille, France
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15
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Devaux C, Clot-Faybesse O, Juin M, Mabrouk K, Sabatier JM, Rochat H. Monoclonal antibodies neutralizing the toxin II from Androctonus australis hector scorpion venom: usefulness of a synthetic, non-toxic analog. FEBS Lett 1997; 412:456-60. [PMID: 9276446 DOI: 10.1016/s0014-5793(97)00826-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Scorpion venom contains toxins that act on ion channels. Some are responsible for the noxious effects observed when people are stung by scorpions. The study of the neutralization of these molecules and the production of monoclonal antibodies (mAbs) should prove valuable. Toxin II from Androctonus australis hector scorpion (AahII) is one of the most potent toxins and has been well-characterized and studied. Producing mAbs against such molecules is often difficult due to their toxicity. We used a synthetic, non-toxic analog, (Abu)8-AahII, to obtain mAbs which recognize and neutralize the native toxin AahII. Sets of peptides spanning the entire sequence of AahII were assayed to identify the binding sites of the mAbs. The various mAbs recognized only the largest peptides (12-17 residues). They recognized peptides corresponding to different parts of the AahII sequence, suggesting that several regions of the (Abu)8-AahII sequence mimic AahII epitopes and then elicit mAbs directed against toxin.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/administration & dosage
- Antibodies, Monoclonal/biosynthesis
- Antibodies, Monoclonal/chemistry
- Binding Sites, Antibody
- Binding, Competitive/immunology
- Epitope Mapping
- Female
- Hybridomas/metabolism
- Injections, Intraperitoneal
- Injections, Intraventricular
- Injections, Subcutaneous
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Molecular Sequence Data
- Neurotoxins/chemical synthesis
- Neurotoxins/immunology
- Neurotoxins/toxicity
- Peptides/chemical synthesis
- Peptides/immunology
- Rats
- Reptilian Proteins
- Scorpion Venoms/chemical synthesis
- Scorpion Venoms/immunology
- Scorpion Venoms/toxicity
- Synaptosomes/immunology
- Synaptosomes/metabolism
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Affiliation(s)
- C Devaux
- CNRS UMR 6560, Laboratoire d'Ingénierie des Protéines, Faculté de Médecine-Nord, Marseille, France.
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16
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Zenouaki I, Kharrat R, Sabatier JM, Devaux C, Karoui H, Van Rietschoten J, el Ayeb M, Rochat H. In vivo protection against Androctonus australis hector scorpion toxin and venom by immunization with a synthetic analog of toxin II. Vaccine 1997; 15:187-94. [PMID: 9066037 DOI: 10.1016/s0264-410x(97)00144-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A synthetic peptide mimicking the North African scorpion Androctonus australis hector toxin II was designed and produced by chemical solid-phase synthesis. It contains the entire sequence of toxin II (64 amino acid residues), with each half-cystine being replaced by the isosteric residue a-aminobutyric acid, and was thus devoid of disulfide bridges. This construct was totally nontoxic in mice even if large amounts, equivalent to 1000 times the LD50 of the original toxin, were injected by the intracerebroventricular route. The synthetic peptide, either as a monomer or polymerized by means of glutaraldehyde, induced the production of antitoxin neutralizing antibodies in immunized mice and rabbits. After three injections with either the monomeric or polymerized synthetic peptide, the immunized mice were protected against several lethal doses of the corresponding native toxin or scorpion venom. Six months after immunization, the mice were completely protected against challenge with eight LD50 of the original toxin. The protection was better when the polymerized synthetic peptide was used. One month after the start of the immunization program, it showed a good correlation between antibody titer and protection. However, antibody titer decreased with time but protection remained high. This suggests that additional factors other than circulating antibodies play a role in protective activity.
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Affiliation(s)
- I Zenouaki
- Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, Tunisia
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17
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Devaux C, Fourquet P, Granier C. A conserved sequence region of scorpion toxins rendered immunogenic induces broadly cross-reactive, neutralizing antibodies. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 242:727-35. [PMID: 9022703 DOI: 10.1111/j.1432-1033.1996.0727r.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Scorpion toxins constitute a family of proteins with a high degree of sequence diversity but a common mode of action. Neutralization of the toxic effects of scorpion stings by serotherapy is limited due to the various serotypes expressed by these proteins. We explored the possibility of raising antibodies to conserved parts of the toxins which could recognize several members of the family. We established the variability profile of a set of 25 scorpion toxin sequences, then evaluated systematically by peptide-scanning methods the antigenicity of one scorpion toxin. The most conserved regions were generally very poorly antigenic. One exception was the N-terminal region, which is both conserved and antigenic. Antibodies were raised in rabbits against an eight-residue synthetic peptide mimicking the N-terminal region. These peptide antibodies were cross-reactive with several scorpion toxins belonging to different serotypes and neutralized both the pharmacological effects (binding to rat brain synaptosomes) and the biological activity (toxicity in mice) of the parent toxin. The molecular model of the toxin indicates that antibody binding to residues 1-8 probably either masks some residue(s) of the N-terminus critical for the biological activity or overlaps with the epitope previously defined by neutralizing monoclonal antibody. These findings could open the way for new therapeutic strategies for the medical care of envenomations.
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Affiliation(s)
- C Devaux
- CNRS URA 1455, Laboratoire de Biochimie, IFR Jean Roche, Faculté de Médecine Nord, Marseille, France
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18
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Koshy BT, Karande AA, Adiga PR. Antigenic determinants at the carboxy terminus of chicken egg white riboflavin carrier protein (RCP): epitope mapping and antibody-mediated pregnancy curtailment in rodents. Vaccine 1996; 14:307-12. [PMID: 8744558 DOI: 10.1016/0264-410x(95)00199-b] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The epitopic core sequences recognized by three monoclonal antibodies raised to chicken riboflavin carrier protein (RCP) were mapped to the C-terminal tail-end of the protein using the pepscan method. A 21-residue synthetic peptide corresponding to residues 200-219 of the protein and comprising the regions corresponding to the antibodies was synthesized. Administration of polyclonal antibodies specific to this peptide led to termination of early pregnancy in mice. Also, active immunization of rats with the peptide-purified protein derivative conjugate inhibited establishment of pregnancy. These results demonstrate the functional importance of the C-terminal 200-219 region of chicken RCP.
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Affiliation(s)
- B T Koshy
- Center for Reproductive Biology and Molecular Endocrinology, Indian Institute of Science, Bangalore, India
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19
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Calderon-Aranda ES, Olamendi-Portugal T, Possani LD. The use of synthetic peptides can be a misleading approach to generate vaccines against scorpion toxins. Vaccine 1995; 13:1198-206. [PMID: 8578804 DOI: 10.1016/0264-410x(95)00059-a] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Seven peptides corresponding to the amino acid sequence of toxin 2 from the scorpion Centruroides noxius were chemically synthesized, purified and assayed in mice for their putative neutralizing properties against scorpion toxins. All the peptides were immunogenic and some produced neutralizing antibodies, as verified by injecting the antisera with toxin into naive animals. However, direct challenge of pre-immunized mice (with the longest synthetic peptides of 27 and 57 amino acid residues) revealed an unexpected sensitization phenomena: the animals did not resist injection of one LD50 of purified toxin 2 (5% survival), but pre-immunization of mice with native toxin protected 100% of the animals. These findings suggest that vaccine preparations with synthetic peptides corresponding to the amino acid sequence of certain toxins should be analyzed cautiously.
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Affiliation(s)
- E S Calderon-Aranda
- Department of Molecular Recognition and Structural Biology, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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