Intraspecies variability in Vipera ammodytes ammodytes venom related to its toxicity and immunogenic potential

High throughput identification of human monoclonal antibodies and heavy-chain-only antibodies to treat snakebite

Snakebite envenoming is a priority Neglected Tropical Disease that causes an estimated 81,000-135,000 fatalities each year. The development of a new generation of safer, affordable, and accessible antivenom therapies is urgently needed. With this goal in mind, rigorous characterisation of the specific toxins in snake venom is key to generating novel therapies for snakebite. Monoclonal antibodies directed against venom toxins are emerging as potentially strong candidates in the development of new snakebite diagnostics and treatment. Venoms comprise many different toxins of which several are responsible for their pathological effects. Due to the large variability of venoms within and between species, formulations of combinations of human antibodies are proposed as the next generation antivenoms. Here a high-throughput screening method employing antibody-based ligand fishing of venom toxins in 384 filter-well plate format has been developed to determine the antibody target/s The approach uses Protein G beads for antibody capture followed by exposure to a full venom or purified toxins to bind their respective ligand toxin(s). This is followed by a washing/centrifugation step to remove non-binding toxins and an in-well tryptic digest. Finally, peptides from each well are analysed by nanoLC-MS/MS and subsequent Mascot database searching to identify the bound toxin/s for each antibody under investigation. The approach was successfully validated to rapidly screen antibodies sourced from hybridomas, derived from venom-immunised mice expressing either regular human antibodies or heavy-chain-only human antibodies (HCAbs).

Venom-Induced Blood Disturbances by Palearctic Viperid Snakes, and Their Relative Neutralization by Antivenoms and Enzyme-Inhibitors

Palearctic vipers are medically significant snakes in the genera Daboia, Macrovipera, Montivipera, and Vipera which occur throughout Europe, Central Asia, Near and Middle East. While the ancestral condition is that of a small-bodied, lowland species, extensive diversification has occurred in body size, and niche specialization. Using 27 venom samples and a panel of in vitro coagulation assays, we evaluated the relative coagulotoxic potency of Palearctic viper venoms and compared their neutralization by three antivenoms (Insoserp Europe, VIPERFAV and ViperaTAb) and two metalloprotease inhibitors (prinomastat and DMPS). We show that variation in morphology parallels variation in the Factor X activating procoagulant toxicity, with the three convergent evolutions of larger body sizes (Daboia genus, Macrovipera genus, and Vipera ammodytes uniquely within the Vipera genus) were each accompanied by a significant increase in procoagulant potency. In contrast, the two convergent evolutions of high altitude specialization (the Montivipera genus and Vipera latastei uniquely within the Vipera genus) were each accompanied by a shift away from procoagulant action, with the Montivipera species being particularly potently anticoagulant. Inoserp Europe and VIPERFAV antivenoms were both effective against a broad range of Vipera species, with Inoserp able to neutralize additional species relative to VIPERFAV, reflective of its more complex antivenom immunization mixture. In contrast, ViperaTAb was extremely potent in neutralizing V. berus but, reflective of this being a monovalent antivenom, it was not effective against other Vipera species. The enzyme inhibitor prinomastat efficiently neutralized the metalloprotease-driven Factor X activation of the procoagulant venoms. In contrast, DMPS (2,3-dimercapto-1-propanesulfonic acid), which as been suggested as another potential treatment option in the absence of antivenom, DMPS failed against all venoms tested. Overall, our results highlight the evolutionary variations within Palearctic vipers and help to inform clinical management of viper envenomation.

Biological Activities and Proteomic Profile of the Venom of Vipera ursinii ssp., a very Rare Karst Viper from Croatia

The karst viper (Vipera ursinii ssp.) favours high-mountain dry grasslands in southern and south-eastern Croatia. It is medically less important than other Vipera species, because of its remote habitat and the very small amount of venom that it injects by its relatively short fangs. The scientific literature on Vipera ursinii deals mostly with the morphology, ecology and distribution range of this snake, due to the species’ conservation issues, while the toxinological aspects of its venom have not so far been investigated. Here we report on the composition and biological activity of the Vipera ursinii ssp. venom. Using a proteomics approach, we have identified 25 proteins in the venom that belong to seven protein families: snake venom metalloproteinase, serine protease, secreted phospholipase A₂, cysteine-rich secretory protein, snake C-type lectin-like protein, serine protease inhibitor and nerve growth factor. The Vipera ursinii ssp. venom was found to be distinctively insecticidal. Its lethal toxicity towards crickets was more than five times greater than that of Vipera ammodytes ammodytes venom, while the opposite held in mice. Interestingly, the mode of dying after injecting a mouse with Vipera ursinii ssp. venom may suggest the presence of a neurotoxic component. Neurotoxic effects of European vipers have so far been ascribed exclusively to ammodytoxins and ammodytoxin-like basic secreted phospholipases A₂. Structural and immunological analyses of the Vipera ursinii ssp. venom, however, confirmed that ammodytoxin-like proteins are not present in this venom.

Development of an LC-MS multivariate nontargeted methodology for differential analysis of the peptide profile of Asian hornet venom (Vespa velutina nigrithorax): application to the investigation of the impact of collection period variation

Insect venom is a highly complex mixture of bioactive compounds, containing proteins, peptides, and small molecules. Environmental factors can alter the venom composition and lead to intraspecific variation in its bioactivity properties. The investigation of discriminating compounds caused by variation impacts can be a key to manage sampling and explore the bioactive compounds. The present study reports the development of a peptidomic methodology based on UHPLC-ESI-QTOF-HRMS analysis followed by a nontargeted multivariate analysis to reveal the profile variance of Vespa velutina venom collected in different conditions. The reliability of the approach was enhanced by optimizing certain XCMS data processing parameters and determining the sample peak threshold to eliminate the interfering features. This approach demonstrated a good repeatability and a criterion coefficient of variation (CV) > 30% was set for deleting nonrepeatable features from the matrix. The methodology was then applied to investigate the impact of collection period variation. PCA and PLS-DA models were used and validated by cross-validation and permutation tests. A slight discrimination was found between winter and summer hornet venom in two successive years with 10 common discriminating compounds. Graphical abstract.

Protein structure of the venom in nine species of snake: from bio-compounds to possible healing agents

Due to its various structures in bio-compounds, snake venom is the indisputable result of evolutionary stages of molecules with an increasingly complex structure, high specificity, and of great importance for medicine because of their potential. The present study proposed an underpinning examination of venom composition from nine species of venomous snakes using a useful and replicable methodology. The objective was the extension of the evaluation of protein fractions in the field up to 230 kDa to permit possible identification of some fractions that are insufficiently studied. The gel capillary electrophoresis method on the chip was performed using an Agilent 2100 bioassay with the 80 and 230-LabChip Protein kits. Interpretation of electrophoresis was performed using the Protein 2100 expert (Agilent) test software as follows: a) Protein 80 (peak size scale): 1.60, 3.5, 6.50, 15.00, 28.00, 46.00, 63.00, 95.00 kDa; b) Protein 230 (peak size scale): 4.50, 7.00, 15.00, 28.00, 46.00, 63.00, 95.00, 150.00, 240.00 kDa. The screening revealed the presence of compounds with a molecular weight greater than 80 kDa, in the case of Vipera aspis and Vipera xantina palestinae. For V. aspis, a 125 kDa molecular weight pro-coagulant protein was identified, known as being involved in the reduction of plasma clotting time without any direct activity in the fibrinogen coagulation process. The samples examined on the Protein 230-LabChip electrophoresis chip can be considered as a novelty with possible uses in medicine, requiring further approaches by advanced proteomics techniques to confirm the intimate structural features and biological properties of snake venoms.

Preclinical Assessment of a New Polyvalent Antivenom (Inoserp Europe) against Several Species of the Subfamily Viperinae

The European continent is inhabited by medically important venomous Viperinae snakes. Vipera ammodytes, Vipera berus, and Vipera aspis cause the greatest public health problems in Europe, but there are other equally significant snakes in specific regions of the continent. Immunotherapy is indicated for patients with systemic envenoming, of which there are approximately 4000 annual cases in Europe, and was suggested as an indication for young children and pregnant women, even if they do not have systemic symptoms. In the present study, the safety and venom-neutralizing efficacy of Inoserp Europe-a new F(ab')₂ polyvalent antivenom, designed to treat envenoming by snakes in the Eurasian region-were evaluated. In accordance with World Health Organization recommendations, several quality control parameters were applied to evaluate the safety of this antivenom. The venom-neutralizing efficacy of the antivenom was evaluated in mice and the results showed it had appropriate neutralizing potency against the venoms of several species of Vipera, Montivipera, and Macrovipera. Paraspecificity of the antivenom was demonstrated as well, since it neutralized venoms of species not included in the immunization schemes and contains satisfactory levels of total proteins and F(ab')₂ fragment concentration. Therefore, this new polyvalent antivenom could be effective in the treatment of snake envenoming in Europe, including Western Russia and Turkey.

Application of the 3R Concept in the Production of European Antiviperinum on Horses – Multisite, Low Volumes Immunization Protocol and Elisa

During time, both professionals and general public became aware of the importance of animal welfare. This term not only covers endangered wild animal species, animals used in food industry, pets and experimental animals, but also animals used in production of biologics. The implementation of the 3R concept (Replacement, Reduction and Refinement) is especially important in this type of production. In this article, we describe for the first time the low dose, low volume and multi-site immunization protocol, as well as appropriate ELISA we developed for production of European anti-viper (V. ammodytes, long horned) antivenom in horses, which can help to significantly improve the welfare of the used animals.

Anti-Ophidian Properties of Herbal Medicinal Plants: Could it be a Remedy for Snake Bite Envenomation?

Snake bite envenoming causes high rates of morbidity and mortality and is one of the serious health-related concerns all over the globe. Around 3200 species of snakes have been discovered till date. Amid these species, about 1300 species of snakes are venomous. On account of its severity, World Health Organization (WHO) recently included snakebite envenoming in the list of neglected tropical diseases. Immunotherapy has partially solved the issues related to snakebite envenomation. However, it is associated with numerous adverse effects, due to which alternative treatment strategies are required for the treatment of snakebite. Traditionally, a large repository of herbal medicinal plants is known to possess activity against snake venom. An exploration of the therapeutic benefits of these medicinal plants used for the treatment of snakebites reveals the presence of various potential phytochemicals. The aim of the present review is to provide an outline regarding poisonous snakes all over the world, various compositions of snake venom, adverse effects related to anti-snake venom and numerous medicinal plants used for the anti-ophidian activity.

Vipera ammodytes bites treated with antivenom ViperaTAb: a case series with pharmacokinetic evaluation

CONTEXT

In clinical practice it is difficult to differentiate between V. berus and V. ammodytes venomous bites. In the past this was not a concern, but due to the current shortage in Viperfav™ and European viper venom antiserum availability, V. a. ammodytes venomous bites have recently been treated with ViperaTAb^®, which is a pharmaceutical formulation containing a monospecific ovine Fab fragments against the venom of V. berus.

OBJECTIVE

To evaluate ViperaTAb^® in V. a. ammodytes envenomations.

MATERIALS AND METHODS

This is a prospective case series of three consecutive patients envenomed by V. a. ammodytes snakebite treated with ViperaTAb^®. V. ammodytes venom, neurotoxic ammodytoxins, and Fab fragment levels were determined in serum samples and a pharmacokinetic analysis of the antivenom Fab fragments was carried out.

RESULTS

Three patients bitten by V. a. ammodytes with extensive local swelling, neurological symptoms and recurrent thrombocytopenia were treated with ViperaTAb^®. V. ammodytes venom was detected in serum of all three patients. Ammodytoxins were detected in the serum of only the most severely envenomed patient who developed neurological symptoms. In the presented moderate cases, a dose of 8 mL of ViperaTAb^® reduced swelling and improved systemic effects, such as thrombocytopenia. However, this dose of ViperaTAb^® was not effective in the most severely envenomed patient with the highest serum values of V. ammodytes venom. In this case ViperaTAb^® did not stop local swelling and it had no effect on neurological signs. ViperaTAb^®'s systemic clearance, distribution and elimination half-lives were 4.3-13.4 mL/h/kg, 1.2-3.2 h and 14.1-55.4 h, respectively.

CONCLUSIONS

In patients envenomed by V. a. ammodytes venom, ViperaTAb^® reduces moderate swelling and temporarily improves systemic effects, except neurological symptoms. ViperaTAb^® application induces a decrement of V. ammodytes venom level in the blood, but did not affect serum concentration of neurotoxic ammodytoxins in the one patient with measurable concentrations.

Influence of post-starvation extraction time and prey-specific diet in Tityus serrulatus scorpion venom composition and hyaluronidase activity

The role of diet in venom composition has been a topic of intense research interest. This work presents evidence that the variation in the venom composition from the scorpion Tityus serrulatus (Ts) is closely associated with post-starvation extraction time and prey-specific diet. The scorpions were fed with cockroach, cricket, peanut beetle or giant Tenebrio. The venoms demonstrated a pronounced difference in the total protein and toxins composition, which was evaluated by electrophoresis, reversed-phase chromatography, densitometry, hyaluronidase activity and N-terminal sequencing. Indeed, many toxins and peptides, such as Ts1, Ts2, Ts4, Ts5, Ts6, Ts15, Ts19 frag. II, hypotensins 1 and 3, PAPE peptide and peptide 9797 (first described in Ts venom), were all identified in different proportions in the analyzed Ts venoms. This study is pioneer on assessing the influence of the starvation time and the prey diet on hyaluronidase activity as well as to describe a modification of Tricine-gel-electrophoresis to evaluate this enzyme activity. Altogether, this study reveal a large contribution of the extraction time and diet on Ts venom variability as well as present a background to recommend the cockroach diet to obtain higher protein content and the cricket diet to obtain higher hyaluronidase specific activity.

Chip electrophoretic separation of highly homologous ammodytoxin isoforms: three neurotoxic phospholipases A2 of Vipera ammodytes ammodytes venom

Ammodytoxins (Atxs), a group of Ca(2+) -dependent neurotoxic phospholipases A2 of Vipera ammodytes ammodytes venom, are mainly responsible for venom toxicity. Within the Atx group, LD50 values between three isoforms, A, B, and C are differing with AtxA exhibiting an LD50 value by an order of magnitude lower (more toxic) than the other two isoforms. This difference in toxicity justifies the necessity to prepare suitable antibodies and thus isoform separation to characterize the Atx content of Vipera ammodytes ammodytes venom is of importance. However, a high homology between the three Atx isoforms (differences in only two, respectively, three residues within the last 18 amino acids at the C-terminus, total length 122 residues) hindered the successful separation of isoforms to date. As the investigated phospholipases A2 were reported to exhibit differences in pI values, we concentrate with the current work on the separation of Atx isoforms after fluorescence labeling via chip electrophoresis on a commercially available instrument to build the basis for a fast and easy to handle screening method. In the course of our work, we were able to show that samples of AtxA, AtxB, and AtxC declared to be homogenous by standard analytical techniques consisted indeed of more than one isoform of which the relative amounts were calculated by using the newly developed method.