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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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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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Khosravi M, Boroun F, Nemati M. The anti-penicillin antibodies levels in sensitive and insensitive people to intradermal skin test. Hum Antibodies 2018; 27:63-68. [PMID: 30223394 DOI: 10.3233/hab-180349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The hypersensitivity reaction to penicillin is a public health problem. Immunological responses to penicillin and other beta-lactam antibiotics can be classified into immediate and non-immediate responses. The immediate hypersensitivity is mediated by IgE; however, the non-immediate sensitivity is facilitated by other isotypes of antibody or T lymphocytes. OBJECTIVE This research detected the non-IgE antibody value against penicillin in allergic and normal people. METHODS Thirty-eight samples from patients with positive or negative intradermal skin testing results of penicillin allergy were included in this study. The total antibody and IgM levels against penicillin G were defined by in-house ELISA test. RESULTS The results showed a significant (P< 0.05) elevation in total immunoglobulin and non-IgM anti-penicillin antibody of sensitive groups; however, the anti-penicillin IgM was significantly greater in non-sensitive peoples. CONCLUSIONS Although the sensitized people to penicillin cannot be certainly detected with the total antibody, specific IgG and IgM value against penicillin, these values are good indicators for prediction of immediate and late response of the immune system to penicillin.
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Affiliation(s)
- Mohammad Khosravi
- Department of Pathobiology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Fatemeh Boroun
- Graduated Student of Microbiology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Mohammad Nemati
- Department of Venomous Animals and Toxins, Razi Vaccine and Serum Research Institute, Ahvaz Branch, Agriculture Research Education and Extension Organization (AREEO), Iran
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Laustsen AH, Solà M, Jappe EC, Oscoz S, Lauridsen LP, Engmark M. Biotechnological Trends in Spider and Scorpion Antivenom Development. Toxins (Basel) 2016; 8:E226. [PMID: 27455327 PMCID: PMC4999844 DOI: 10.3390/toxins8080226] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 06/19/2016] [Accepted: 07/13/2016] [Indexed: 12/28/2022] Open
Abstract
Spiders and scorpions are notorious for their fearful dispositions and their ability to inject venom into prey and predators, causing symptoms such as necrosis, paralysis, and excruciating pain. Information on venom composition and the toxins present in these species is growing due to an interest in using bioactive toxins from spiders and scorpions for drug discovery purposes and for solving crystal structures of membrane-embedded receptors. Additionally, the identification and isolation of a myriad of spider and scorpion toxins has allowed research within next generation antivenoms to progress at an increasingly faster pace. In this review, the current knowledge of spider and scorpion venoms is presented, followed by a discussion of all published biotechnological efforts within development of spider and scorpion antitoxins based on small molecules, antibodies and fragments thereof, and next generation immunization strategies. The increasing number of discovery and development efforts within this field may point towards an upcoming transition from serum-based antivenoms towards therapeutic solutions based on modern biotechnology.
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Affiliation(s)
- Andreas Hougaard Laustsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen East, Denmark.
| | - Mireia Solà
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
| | - Emma Christine Jappe
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
| | - Saioa Oscoz
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
| | - Line Præst Lauridsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
| | - Mikael Engmark
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
- Department of Bio and Health Informatics, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
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Carmo AO, Chatzaki M, Horta CCR, Magalhães BF, Oliveira-Mendes BBR, Chávez-Olórtegui C, Kalapothakis E. Evolution of alternative methodologies of scorpion antivenoms production. Toxicon 2015; 97:64-74. [PMID: 25701676 DOI: 10.1016/j.toxicon.2015.02.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Revised: 11/10/2014] [Accepted: 02/17/2015] [Indexed: 12/23/2022]
Abstract
Scorpionism represents a serious public health problem resulting in the death of children and debilitated individuals. Scorpion sting treatment employs various strategies including the use of specific medicines such as antiserum, especially for patients with severe symptoms. In 1909 Charles Todd described the production of an antiserum against the venom of the scorpion Buthus quinquestriatus. Based on Todd's work, researchers worldwide began producing antiserum using the same approach i.e., immunization of horses with crude venom as antigen. Despite achieving satisfactory results using this approach, researchers in this field have developed alternative approaches for the production of scorpion antivenom serum. In this review, we describe the work published by experts in toxinology to the development of scorpion venom antiserum. Methods and results describing the use of specific antigens, detoxified venom or toxins, purified toxins and or venom fractions, native toxoids, recombinant toxins, synthetic peptides, monoclonal and recombinant antibodies, and alternative animal models are presented.
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Affiliation(s)
- A O Carmo
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil.
| | - M Chatzaki
- Department of Molecular Biology & Genetics, Democritus University of Thrace, University Campus, 69100 Komotini, Greece.
| | - C C R Horta
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil.
| | - B F Magalhães
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil.
| | - B B R Oliveira-Mendes
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil.
| | - C Chávez-Olórtegui
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil.
| | - E Kalapothakis
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil.
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Khoobdel M, NikbakhtBoroujeni G, ZahraeiSalehi T, Khosravi M, Sasani F, Bokaei S, Koochakzadeh A, Zamani-Ahmadmahmudi M, Akbari A. Diagnosis of Mesobuthus eupeus envenomation by skin test: reverse passive Arthus reaction. Toxicon 2013; 77:133-40. [PMID: 24269785 DOI: 10.1016/j.toxicon.2013.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 11/07/2013] [Accepted: 11/12/2013] [Indexed: 11/30/2022]
Abstract
While being stung by two large families of scorpions, Buthidae and Scorpionidae have different symptoms and complications, a similar maintenance treatment usually considers as the scorpion species could not be identified easily. Therefore, this study was an attempt to develop an immunologic response for designing a skin sensitivity test that can be used to determine the poisoning. The sensitivity and the specificity of RPA reaction for detecting experimental envenomated mice were evaluated. The inflammatory response for detection of envenomation was obtained by the injection of a solution containing complement, polyelectrolytes and purified monovalent antibodies. As the result, 84.44% sensitivity and 100% specificity recorded 15 min after challenge. Macroscopic findings were also confirmed histologically. No cross-reactions were observed with other species of scorpions and snake venoms. Designed Skin test induced obvious inflammatory reaction without any histological lesions. Besides adding the complement components and polyelectrolyte to the monovalent antibody leads to an increased susceptibility of inflammatory cells in this reaction, resulting in forming a visible inflammation in a short time. According to satisfactory specificity and sensitivity and visible results in about 15 min, non-harmful and cost benefity of reverse passive Arthus test can be used for diagnosis of scorpion envenomation.
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Affiliation(s)
- M Khoobdel
- Health Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Gh NikbakhtBoroujeni
- Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - T ZahraeiSalehi
- Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - M Khosravi
- Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran.
| | - F Sasani
- Department of Pathology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - S Bokaei
- Department of Epidemiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - A Koochakzadeh
- Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - M Zamani-Ahmadmahmudi
- Department of Clinical Science, Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran
| | - A Akbari
- Razi Vaccine and Serum Research Institute-Karaj Branch, Karaj, Iran
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Khoobdel M, Nayeri Fasaei B, Zahraei Salehi T, Khosravi M, Taheri M, Koochakzadeh A, Masihipour B, Motedayen MH, Akbari S. The production of monovalent and anti-idiotype antivenom against Mesobuthus eupeus (Scorpionida: Buthidae) venom in rabbits. Toxicon 2013; 76:44-9. [PMID: 24055069 DOI: 10.1016/j.toxicon.2013.09.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 08/30/2013] [Accepted: 09/06/2013] [Indexed: 11/28/2022]
Abstract
The antivenom production against poisonous creatures encounters a number of difficulties. Interestingly, according to the network theory the conventional antigens are not necessarily needed for producing antibodies against the venoms. In this investigation, the antivenom against Mesobuthus eupeus venom was produced based on the aforementioned theory. Polyclonal antibodies against M. eupeus venom were obtained from the immunized rabbits and the specific antibodies were isolated. After separation of Fab2, immunization process and production of the monovalent and anti-idiotype, these antivenoms were analyzed for the determination of their neutralizing power. The level of the produced antibodies in different stages of this study was also measured by ELISA assay. Four hundred and fifty micrograms of the venom can be neutralized by 4.2, 18 and 291 mg of monovalent, polyvalent and anti-idiotype antivenom, respectively. The ELISA results revealed that idiotypic antigens were six times more immunogenic than anti-idiotypes. The anti-idiotype antivenom can be produced on a large scale with minimum venom consumption. In addition, they are non-toxicant in immunized animals and can be used as a vaccine in people at the risk of scorpion stings.
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Affiliation(s)
- M Khoobdel
- Health Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
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Brenneis C, Sisignano M, Coste O, Altenrath K, Fischer MJ, Angioni C, Fleming I, Brandes RP, Reeh PW, Woolf CJ, Geisslinger G, Scholich K. Soluble epoxide hydrolase limits mechanical hyperalgesia during inflammation. Mol Pain 2011; 7:78. [PMID: 21970373 PMCID: PMC3195722 DOI: 10.1186/1744-8069-7-78] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 10/04/2011] [Indexed: 11/29/2022] Open
Abstract
Background Cytochrome-P450 (CYP450) epoxygenases metabolise arachidonic acid (AA) into four different biologically active epoxyeicosatrienoic acid (EET) regioisomers. Three of the EETs (i.e., 8,9-, 11,12- and 14,15-EET) are rapidly hydrolysed by the enzyme soluble epoxide hydrolase (sEH). Here, we investigated the role of sEH in nociceptive processing during peripheral inflammation. Results In dorsal root ganglia (DRG), we found that sEH is expressed in medium and large diameter neurofilament 200-positive neurons. Isolated DRG-neurons from sEH-/- mice showed higher EET and lower DHET levels. Upon AA stimulation, the largest changes in EET levels occurred in culture media, indicating both that cell associated EET concentrations quickly reach saturation and EET-hydrolyzing activity mostly effects extracellular EET signaling. In vivo, DRGs from sEH-deficient mice exhibited elevated 8,9-, 11,12- and 14,15-EET-levels. Interestingly, EET levels did not increase at the site of zymosan-induced inflammation. Cellular imaging experiments revealed direct calcium flux responses to 8,9-EET in a subpopulation of nociceptors. In addition, 8,9-EET sensitized AITC-induced calcium increases in DRG neurons and AITC-induced calcitonin gene related peptide (CGRP) release from sciatic nerve axons, indicating that 8,9-EET sensitizes TRPA1-expressing neurons, which are known to contribute to mechanical hyperalgesia. Supporting this, sEH-/- mice showed increased nociceptive responses to mechanical stimulation during zymosan-induced inflammation and 8,9-EET injection reduced mechanical thresholds in naive mice. Conclusion Our results show that the sEH can regulate mechanical hyperalgesia during inflammation by inactivating 8,9-EET, which sensitizes TRPA1-expressing nociceptors. Therefore we suggest that influencing the CYP450 pathway, which is actually highly considered to treat cardiovascular diseases, may cause pain side effects.
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Affiliation(s)
- Christian Brenneis
- Pharmazentrum Frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe-University, Frankfurt, Germany.
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Abbas N, Rosso JP, Céard B, Belghazi M, Lebrun R, Bougis PE, Martin-Eauclaire MF. Characterization of three "Birtoxin-like" toxins from the Androctonus amoreuxi scorpion venom. Peptides 2011; 32:911-9. [PMID: 21335045 DOI: 10.1016/j.peptides.2011.02.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 02/07/2011] [Accepted: 02/09/2011] [Indexed: 12/19/2022]
Abstract
The venom of the North African scorpion Androctonus amoreuxi (Aam) was analyzed using a combination of gel filtration, C18 reverse phase HPLC together with mass spectrometry analysis and bioassays. Three novel Birtoxin-like (BTX-L) peptides of 58 amino acid residues comprising three disulfide bridges were isolated and chemically characterized. One peptide, AamBTX-L3, induced serious toxic symptoms in mice and was lethal at nanogram quantities using intracerebroventricular injection. The three BTX-L peptides were tested in competition experiments on rat brain synaptosomes against the (125)I-labeled "classical" α- and β-toxins of reference, as well as with the (125)I-KTX, a voltage-gated potassium channel blocker. Only AamBTX-L3 was able to prevent the equilibrium binding of the β-toxin (125)I-Css IV to its receptor site 4 with a IC(50) value of 189 nM. Even if previous electrophysiological data allowed the classification of other BTX-L peptides among the β-type toxins, this report clearly shows that AamBTX-L3 is pharmacologically a β-toxin, which recognizes the voltage-gated Na(+) (Na(v)) channels from central mammalian neurons. In order to uncover the residues functionally essential for interaction between the AamBTX-L3 with the putative receptor site of (125)I-Css IV on Na(v)1.2, molecular models of the three novel Aam BTX-L molecules were made and their surfaces were compared to the already described Css IV biologically interactive surfaces. A hypothesis is given that in BTX-L3, three residues found in the α-helix play a key role during target binding.
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Affiliation(s)
- Najwa Abbas
- CNRS UMR6231, CRN2M, Université de la Méditerranée, Faculté de Médecine secteur Nord, CS80011, Bd Pierre Dramard, F-13344 Marseille Cedex 15, France
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García-Gómez BI, Olamendi-Portugal TC, Paniagua J, van der Walt J, Dyason K, Possani LD. Heterologous expression of a gene that codes for Pg8, a scorpion toxin of Parabuthus granulatus, capable of generating protecting antibodies in mice. Toxicon 2009; 53:770-8. [DOI: 10.1016/j.toxicon.2009.02.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Revised: 01/22/2009] [Accepted: 02/02/2009] [Indexed: 10/21/2022]
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Gulumian M. The Perception and Practice of Toxicology in South Africa. Chem Res Toxicol 2008; 22:3-5. [DOI: 10.1021/tx800387j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mary Gulumian
- National Institute for Occupational Health andDepartment of Haematology and Molecular MedicineFaculty of Health SciencesUniversity of the WitwatersrandP.O. Box 4788Johannesburg 2000, South AfricaTel: E-mail:
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Immunological characterization of a non-toxic peptide conferring protection against the toxic fraction (AahG50) of the Androctonus australis hector venom. Toxicon 2008; 51:353-62. [PMID: 18054371 DOI: 10.1016/j.toxicon.2007.10.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2007] [Revised: 09/01/2007] [Accepted: 10/16/2007] [Indexed: 11/20/2022]
Abstract
KAaH1 and KAaH2 are non-toxic peptides, isolated from the venom of the Androctonus australis hector (Aah) scorpion. In a previous study, we showed these peptides to be the most abundant (approximately 10% each) in the toxic fraction (AahG50) of the Aah venom. KAaH1 and KAaH2 showed high sequence identities (approximately 60%) with birtoxin-like peptides, which likewise are the major peptidic components of Parabuthus transvaalicus scorpion venom. Here, we report the immunological characterization of KAaH1 and KAaH2. These peptides were found to be specifically recognized by polyclonal antibodies raised against AahII, the most toxic peptide of Aah venom, and represents the second antigenic group, including toxins from different scorpion species in the world. Moreover, KAaH1 partially inhibits AahII binding to its specific antibody, suggesting some common epitopes between these two peptides. The identification of possible key antigenic residues in KAaH1 was deduced from comparison of its 3-D model with the experimental structure of AahII. Two clusters of putative antigenically important residues were found at the exposed surface; one could be constituted of V3 and D53, the other of D10, T15 and Y16. Polyclonal antibodies raised against KAaH1 in mice were found to cross-react with both AahII and AahG50, and neutralizing 5LD(50)/ml of the toxic fraction. Mice vaccinated with KAaH1 were protected against a challenge of 2LD(50) of AahG50 fraction. All these data suggest that KAaH1 has clear advantages over the use of the whole or part of the venom. KAaH1 is not toxic and could produce sera-neutralizing scorpion toxins, not only from Aah venom, but also toxins of other venoms from Buthus, Leiurus, or Parabuthus scorpion species presenting antigenically related toxins.
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