Anti-Cancer Activity of Buthus occitanus Venom on Hepatocellular Carcinoma in 3D Cell Culture.

Hepatocellular carcinoma (HCC) is the most dominant primary liver cancer, which can be caused by chronic hepatitis virus infections and other environmental factors. Resection, liver transplantation, and local ablation are only a few of the highly effective and curative procedures presently accessible. However, other complementary treatments can reduce cancer treatment side effects. In this present work, we evaluated the activity of Moroccan scorpion venom Buthus occitanus and its fractions obtained by chromatography gel filtration against HCC cells using a 3D cell culture model. The venom was fractionated by gel filtration chromatography, each fraction and the crude venom was tested on normal hepatocytes (Fa2N-4 cells). Additionally, the fractions and the crude venom were tested on MCTSs (multicellular tumor spheroids), and this latter was generated by cultivate Huh7.5 cancer cell line with WI38 cells, LX2 cells, and human endothelial cells (HUVEC). Our results indicate that Buthus occitanus venom toxin has no cytotoxic effects on normal hepatocytes. Moreover, it is reported that F3 fraction could significantly inhibit the MCTS cells. Other Protein Separation Techniques (High-performance liquid chromatography) are needed in order to identify the most active molecule.

Characterization of Am IT, an anti-insect ß-toxin isolated from the venom of scorpion Androctonus mauretanicus.

In the present study, a 'novel' toxin, called Am IT from the venom of scorpion Androctonus mauretanicus is isolated and characterized. A detailed analysis of the action of Am IT on insect axonal sodium currents is reported. Am IT was purified through gel filtration followed by C18 reversed-phase HPLC. Toxicity of Am IT in vivo was assessed on male German cockroach (Blattella germanica) larvae and C57/BL6 mice. Cross-reactivity of Am IT with two ß-toxins was evidenced using (125)I-iodinated toxin-based radioimmunoassays with synaptosomal preparations from rat brain. The complete amino acid sequence of Am IT was finally determined by Edman sequencing. Am IT was observed to compete with AaH IT4 purified from the venom of scorpion Androctonus australis in binding assays. It was recognized by an antibody raised against a ß-type toxin, which indicated some structural similarity with ß-toxins (or related toxin family). The 'novel' toxin exhibited dual activity since it competed with anti-mammal toxins in binding assays as well as showed contracting activity to insect. The toxin competed with radio-labeled ß-toxin Css IV by binding to Na(+) channels of rat brain synaptosomes. Analysis of toxin amino acid sequences showed that Am IT shares high structural identity (92%) with AaH IT4. In conclusion, Am IT not only reveals an anti-insect compound properties secreted by 'Old World' scorpions, paralyzing insect larvae by binding to Na(+) channels on larvae's nerve-cell membranes, but also exerts toxic activity in mice, which is similar to anti-mammal toxins from 'New World' scorpions (North and South Americas). Therefore, Am IT appears to be structurally and functionally similar to AaH IT4.

Development and Efficacy of the Antivenom Specific to Severe Envenomations in Morocco and North Africa: Advancements in Scorpion Envenomation Management.

Scorpion envenomation poses a global public health issue, with an estimated 1,500,000 cases worldwide annually resulting in 2600 deaths. North Africa, particularly Morocco, experiences severe envenomations, mainly attributed to Androctonus mauretanicus and Buthus occitanus in Morocco, and Buthus occitanus and Androctonus australis hector in Algeria and Tunisia, with case numbers often underestimated. Current treatment relies mainly on symptomatic approaches, except in Morocco, where management is limited to symptomatic treatment due to controversies regarding specific treatment. In Morocco, between 30,000 and 50,000 scorpion envenomation cases are reported annually, leading to hundreds of deaths, mainly among children. Controversies among clinicians persist regarding the appropriate course of action, often limiting treatments to symptomatic measures. The absence of a specific antivenom for the venoms of the most lethal scorpions further exacerbates the situation. This study aims to address this gap by developing a monovalent antivenom against the endemic and most dangerous scorpion, Androctonus mauretanicus. The antivenom was produced by immunizing albino rabbits with a mixture of Androctonus mauretanicus venom collected from high-risk areas in Morocco. Immunizations were performed by subcutaneous injections at multiple sites near the lymphatic system, following an immunization schedule. Production control of neutralizing antibody titers was conducted through immunodiffusion. Once a sufficient antibody titer was achieved, blood collection was performed, and the recovered plasma underwent affinity chromatography. The efficacy of purified IgG was evaluated by determining the ED50 in mice, complemented by histological and immunohistochemical studies on its ability to neutralize venom-induced tissue alterations and the neutralization of toxins bound to receptors in the studied organs. The monovalent antivenom demonstrated specificity against Androctonus mauretanicus venom and effective cross-protection against the venom of the scorpions Buthus occitanus and Androctonus australis hector, highly implicated in lethal envenomations in the Maghreb. This study shows that the developed monovalent antivenom exhibits notable efficacy against local scorpions and a surprising ability to neutralize the most lethal envenomations in North Africa. These results pave the way for a new, more specific, and promising therapeutic approach to countering severe scorpion envenomations, especially in Morocco, where specific treatment is lacking.

Epidemiological, clinical, biological and evolutionary profile of scorpion envenomed children under one year to 15 years in the Souss Massa region of Morocco.

Morocco is one of the main countries affected in North African with the scorpion envenomations. Faced with the threat, significant morbidity and a major risk of death especially in children, a detailed identification of scorpionic profile of stings remains important for health authorities at national or even regional level. The current study aims to establish the epidemiological, clinical, biological and evolutionary data of the scorpionism by analyzing 383 cases of scorpion stings in children from three age groups (<1 year, 1-5 years and >5 years), admitted at the Regional Hospital Hassan II-Agadir in the Souss Massa region during the period of 9 years and 10 months from January 2013 to October 2022. Our results showed that patients under 1 year of age presented the most severe cases and had the highest mortality rate. However, the clinical signs and symptoms observed illustrated severe damages to vital systems, particularly the cardiovascular, neurological and pulmonary systems, although the signs associated with the latter were present only in cases admitted in grades 2 and 3 for the three age categories studied. Fluctuations in vital constants (temperature and peripheral oxygen saturation, blood pressure, heart rate and respiratory rate), biochemical parameters (ASAT, ALAT, urea and blood creatine, as well as blood sugar) and CBC results revealed major functional disturbances in vital organs, especially in envenomated cases admitted in grade 3. A positive correlation was mentioned between the state of evolution and the various epidemiological parameters, digestive symptoms, as well as signs and symptoms linked to hemodynamic state, general and neurological state. The main interest is to illustrate the seriousness of scorpion envenomations, especially in the high-risk population, for whom an improved therapeutic approach in health centers will undoubtedly be reinforced, and the admission of immunotherapy, as a fundamental part of the treatment, remains important.

Comparative Proteomic Analysis of the Venoms from the Most Dangerous Scorpions in Morocco: Androctonus mauritanicus and Buthus occitanus.

Morocco is known to harbor two of the world's most dangerous scorpion species: the black Androctonus mauritanicus (Am) and the yellow Buthus occitanus (Bo), responsible for 83% and 14% of severe envenomation cases, respectively. Scorpion venom is a mixture of biological molecules of variable structures and activities, most of which are proteins of low molecular weights referred to as toxins. In addition to toxins, scorpion venoms also contain biogenic amines, polyamines, and enzymes. With the aim of investigating the composition of the Am and Bo venoms, we conducted an analysis of the venoms by mass spectrometry (ESI-MS) after separation by reversed-phase HPLC chromatography. Results from a total of 19 fractions obtained for the Am venom versus 22 fractions for the Bo venom allowed the identification of approximately 410 and 252 molecular masses, respectively. In both venoms, the most abundant toxins were found to range between 2-5 kDa and 6-8 kDa. This proteomic analysis not only allowed the drawing of an extensive mass fingerprint of the Androctonus mauritanicus and Buthus occitanus venoms but also provided a better insight into the nature of their toxins.

Insight into the Toxicological and Pathophysiological Effects of Moroccan Vipers' Venom: Assessing the Efficacy of Commercial Antivenom for Neutralization.

Morocco is one of the richest countries in biodiversity in the Mediterranean region, especially in its ophidian fauna. In total, there are eight species of venomous snakes, with seven belonging to the Viperidae family, responsible for 67.2% of severe envenomation cases in the country. Cerastes cerastes, Daboia mauritanica and Bitis arietans are considered among the most venomous vipers whose bites cause high levels of morbidity, disability or mortality. Despite their wide distribution in the kingdom, the incidence of these snakebites remains poorly understood and largely underestimated. Moreover, intraspecific variations in the venom composition significantly affect the effectiveness of antivenoms. Due to the unavailability of locally produced antivenoms, we evaluated the efficacy of Inoserp-MENA, the only available antivenom in Morocco, against C. cerastes, D. mauritanica and B. arietans. First, we conducted a comprehensive characterization of these venoms, including an LD50 test to examine their toxicity and SDS-PAGE as a technique to analyze the enzymes responsible for biological activities, such as hemorrhagic and edematous activities and myotoxicity, which generate physiopathological effects in the skin, paws and muscles of envenomed mice. Then, we assessed the ability of Inoserp-MENA antivenom to neutralize the toxic activities of Moroccan vipers. Our results indicate that the venom of C. cerastes, D. mauritanica and B. arietans are toxic, causing severe alterations such as edema, myotoxicity, myonecrosis and significant hemorrhages with the formation of hemorrhagic foci. C. cerastes venom is more dangerous in terms of lethality and hemorrhages, while B. arietans venom is more edematous. The effects of C. cerastes venom were effectively neutralized, but Inoserp-MENA antivenom failed to protect mice against the toxic effects induced by B. arietans and D. mauritanica venom. The study reveals alarming shortcomings in the effectiveness of the current commercially available antivenom's dosage and neutralization capabilities, highlighting the urgent need to develop a region-specific viper envenomation therapy.

Assessing the Efficacy of Monovalent and Commercialized Antivenoms for Neutralizing Moroccan Cobra Naja haje Venom: A Comparative Study.

In Morocco, eight species of venomous snakes belonging to the Viperidae and Elapidae families are responsible for severe envenomation cases. The species from the Elapidae family is only represented by the medically relevant cobra Naja haje, which is widely distributed in North Africa. However, there is little information on the systemic effects of Moroccan cobra venom on vital organs due to regional variations. It has been demonstrated that the venom of Naja haje from Egypt causes hemorrhage, while the venom of the Moroccan cobra is neurotoxic and devoid of systemic bleeding. This variability is known to significantly influence treatment efficacy against Naja haje cobra bites in the Middle East. In this study, we examined the pathophysiological mechanisms responsible for the lethality induced by Naja haje venom, as well as the evaluation of the neutralizing capacity of two antivenoms; the monospecific antivenom made for Naja haje only and the antivenom marketed in the Middle East and North Africa. We first determined the toxicity of Naja haje venom by LD50 test, then compared the neutralizing capacity of the two antivenoms studied by determining the ED50. We also performed histological analysis on Swiss mice envenomed and treated with these antivenoms to observe signs of cobra venom envenomation and the degree of reduction of induced systemic alterations. The results showed significant differences between both antivenoms in terms of neutralization. The monospecific antivenom was four times more effective than the marketed antivenom. These results were confirmed by a histological study, which showed that monospecific antivenoms neutralized severe signs of mortality, such as congestion of blood vessels in the heart and kidneys, pulmonary and renal edema, cytoplasmic vacuolization of hepatocytes in the liver, and infiltration of inflammatory cells in the brain and spleen. However, the polyvalent antivenom failed to protect all severe lesions induced by Naja haje venom in mice. These findings highlight the negative impact of geographic variation on the effectiveness of conventional antivenom therapy and confirm the need for a specific Naja haje antivenom for the effective treatment of cobra envenomation in Morocco.

Neutralization Capacity of Tissue Alterations Caused by the Venoms of the Most Dangerous Scorpions in North Africa Using a Selective Antivenom.

In North Africa, scorpion stings pose an urgent public health problem, particularly for children with high morbidity and mortality rates. The main species implicated are the Androctonus mauretanicus (Am), Androctonus australis hector (Aah), and Buthus occitanus (Bo). Immunotherapy is the specific therapeutic approach aimed at directly neutralizing toxins, despite their severity and rapid diffusion. In the present study, we evaluate, histologically and immunohistologically, the neutralization potency of the selective antivenom produced against, among other species, the Am, Aah, and Bo at the level of the tissue alterations in Swiss mice, as experimental subjects. Firstly, the lethal doses 50 test was conducted to assess the venom's toxic activity, and then the median effective dose of the antivenom was determined against each venom. The histological and immunohistological analyses were performed by injecting the sublethal dose of venom, the complex venom and antivenom, or the antivenom 2 h following inoculation of venom. Our study revealed the highest toxicity of the Am, followed by the Aah and then the Bo venom. The neutralizing ability and effectiveness of the antivenom to completely or partially neutralize the tissular damages were demonstrated in all organs studied: brain, heart, lungs, liver, and kidneys. Our results highlighted the important cytoplasmic and membranous staining in the heart compared to the brain tissue for the three scorpion venoms. Therefore, the scorpionic antivenoms are able to reach their target even at the tissue level. Immunotherapy represents the specific and recommended treatment against the scorpionic stings in North Africa.

Computational screening of potential drugs against COVID-19 disease: the Neuropilin-1 receptor as molecular target.

The transmembrane receptor Neuropilin-1 (NRP-1) was reported to serve as a host cell entry factor for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of COVID-19 disease. Therefore, molecular compounds interfering with SARS-CoV-2 binding to NRP-1 seem to be potential candidates as new antiviral drugs. In this study, NRP-1 receptor was targeted using a library of 1167 compounds previously analyzed in COVID-19 related studies. The results show the effectiveness of Nafamostat, Y96, Selinexor, Ebastine and UGS, in binding to NRP-1 receptor, with docking scores lower than - 8.2 kcal/mol. These molecules interact with NRP-1 receptor key residues, which makes them promising drugs to pursue further biological assays to explore their potential use in the treatment of COVID-19. Supplementary Information: The online version contains supplementary material available at 10.1007/s13337-021-00751-x.

Mass spectrometry-based top-down and bottom-up approaches for proteomic analysis of the Moroccan Buthus occitanus scorpion venom.

Buthus occitanus (B. occitanus) is one of the most dangerous scorpions in the world. Despite the involvement of B. occitanus scorpion in severe cases of envenomation in Morocco, no study has focused yet on the proteomic composition of the Moroccan B. occitanus scorpion venom. Mass spectrometry-based proteomic techniques are commonly used in the study of scorpion venoms. The implementation of top-down and bottom-up approaches for proteomic analyses facilitates screening by allowing a global view of the structural aspects of such complex matrices. Here, we provide a partial overview of the venom of B. occitanus scorpion, in order to explore the diversity of its toxins and hereafter understand their effects. To this end, a combination of top-down and bottom-up approaches was applied using nano-high liquid chromatography coupled to nano-electrospray tandem mass spectrometry (nano-LC-ESI MS/MS). The LC-MS results showed that B. occitanus venom contains around 200 molecular masses ranging from 1868 to 16 720 Da, the most representative of which are those between 5000 and 8000 Da. Interestingly, combined top-down and bottom-up LC-MS/MS results allowed the identification of several toxins, which were mainly those acting on ion channels, including those targeting sodium (NaScTxs), potassium (KScTxs), chloride (ClScTxs), and calcium channels (CaScTx), as well as antimicrobial peptides (AMPs), amphipathic peptides, myotropic neuropeptides, and hypothetical secreted proteins. This study reveals the molecular diversity of B. occitanus scorpion venom and identifies components that may have useful pharmacological activities.

Anti-Cancer Effect of Moroccan Cobra Naja haje Venom and Its Fractions against Hepatocellular Carcinoma in 3D Cell Culture.

Hepatocellular carcinoma (HCC) is the most common primary liver cancer in adults, the fifth most common malignancy worldwide and the third leading cause of cancer related death. An alternative to the surgical treatments and drugs, such as sorafenib, commonly used in medicine is necessary to overcome this public health problem. In this study, we determine the anticancer effect on HCC of Moroccan cobra Naja haje venom and its fraction obtained by gel filtration chromatography against Huh7.5 cancer cell line. Cells were grown together with WI38 human fibroblast cells, LX2 human hepatic stellate cell line, and human endothelial cells (HUVEC) in MCTS (multi-cellular tumor spheroids) models. The hepatotoxicity of venom and its fractions were also evaluated using the normal hepatocytes cell line (Fa2N-4 cells). Our results showed that an anti HCC activity of Moroccan cobra Naja haje venom and, more specifically, the F7 fraction of gel filtration chromatography exhibited the greatest anti-hepatocellular carcinoma effect by decreasing the size of MCTS. This effect is associated with a low toxicity against normal hepatocytes. These results strongly suggest that the F7 fraction of Moroccan cobra Naja haje venom obtained by gel filtration chromatography possesses the ability to inhibit cancer cells proliferation. More research is needed to identify the specific molecule(s) responsible for the anticancer effect and investigate their mechanism of action.

The new COST Action European Venom Network (EUVEN)-synergy and future perspectives of modern venomics.

Venom research is a highly multidisciplinary field that involves multiple subfields of biology, informatics, pharmacology, medicine, and other areas. These different research facets are often technologically challenging and pursued by different teams lacking connection with each other. This lack of coordination hampers the full development of venom investigation and applications. The COST Action CA19144-European Venom Network was recently launched to promote synergistic interactions among different stakeholders and foster venom research at the European level.

New analysis of the toxic compounds from the Androctonus mauretanicus mauretanicus scorpion venom.

Scorpion venoms are very complex mixtures of molecules, most of which are peptides displaying different kinds of biological activity. Indeed, these peptides specifically bind to a variety of pharmacological targets, in particular ionic channels located in prey tissues, resulting in neurotoxic effects. Toxins modulating Na+, K+, Ca2+ and Cl(-) currents have been described in scorpion venoms. In this work, we have used several specific antibodies raised against the most lethal scorpion toxins already described to screen the Moroccan scorpion Androctonus mauretanicus mauretanicus venom in order to characterize new compounds. This immunological screening was also implemented by toxicity tests in mice and with mass spectrometry study, providing new informations on the molecular composition of this venom. In fine, we were able to determine the molecular masses of 70-80 different compounds. According to the immunological data obtained, many toxins cross-react with three sera raised against the most lethal alpha-toxins found in North African scorpion venoms, but not at all with those raised against the main beta-toxins from South and North American venoms. Some of the previously described toxins from Androctonus mauretanicus mauretanicus venom could thus be detected by combining immunological tests, toxicity in mice and molecular masses. Among these toxins, one of them, which showed a mild cross-reaction with the serum raised against AaH I (a highly potent toxin from the venom of Androctonus australis), was identified as Amm III and fully sequenced.

Consequences of Androctonus mauretanicus and Buthus occitanus scorpion venoms on electrolyte levels in rabbits.

Androctonus mauretanicus (A. mauretanicus) and Buthus occitanus (B. occitanus) scorpions, which belong to the Buthidae family, are the most venomous scorpions in Morocco. For the first time, we investigated the effects of such scorpion venoms on serum electrolytes in subcutaneously injected rabbits. For this purpose, 3 groups of 6 albinos adult male rabbits (New Zealand) were used in this experiment. Two of the groups were given a single subcutaneous injection of either crude Am venom (5 µg/kg) or Bo venom (8 µg/kg) whereas the third group (control group) only received physiological saline solution (NaCl 0.9%). The blood samples were collected from injected rabbits via the marginal vein at time intervals of 30 min, 1 h, 2 h, 4 h, 6 h and 24 h after venom injection. The concentrations of electrolytes in the serum samples were measured. Our study indicates that scorpion envenomation in vivo, rabbit animal model, caused severe and persistent hypomagnesaemia and hypochloremia, which are accompanied of hypernatremia, hyperkalemia and hypercalcaemia. The intensity of electrolytes imbalance was clearly superior in the case of A. mauretanicus scorpion venom (although a lower quantity of venom was injected). This is coherent with the experimental data which indicate that A. mauretanicus venom is more toxic than B. occitanus venom.

Comparison of the neurotoxic and myotoxic effects of two Moroccan scorpion venoms and their neutralization by experimental polyclonal antivenom.

AIMS: Scorpion venoms contain complex mixtures of molecules, including peptides. These peptides specifically bind to various targets, in particular ion channels. Toxins modulating Na(+), K(+), Ca(2+) and Cl(-) currents were described from venoms. The Androctonus and Buthus geni of scorpions are widely distributed in Morocco. Their stings can cause pain, inflammation, necrosis, muscle paralysis and death. The myotoxicity is predominantly associated with neurotoxic effects and is a cause of mortality and morbidity. In this study, pharmacological effects of venoms were investigated in vitro on neuromuscular transmission. MAIN METHODS: Effects of Androctonus mauretanicus (Am) and Buthus occitanus (Bo) venoms were investigated using the chick biventer cervicis nerve-muscle preparations. The protective activity of antivenom was also investigated. The antivenom was made from serum of horse that was hyperimmunized with Bo and Androctonus australis hector (Aah) venoms and one venom from Middle East species (Lq). The protective activity of the antivenom was assessed on the neuromuscular system by using stimulated chick nerve-muscle. The results were compared with lethal activity neutralization in mice. KEY FINDINGS: Am and Bo venoms contain myotoxins and postsynaptic neurotoxins. In agreement with lethal potencies of these venoms in mice, Am venom displays greater neurotoxicity and myotoxicity. The antivenom prevented lethality caused by Am, Bo and Aah venoms. The antivenom did not prevent toxic effects caused by Am venom whereas it neutralized Bo venom. SIGNIFICANCE: Am and Bo venoms contain distinct toxins that are responsible for myotoxicity and neurotoxicity. It would be appropriate to add Am venom to produce more efficient antivenom.

Evaluation of the lethal potency of scorpion and snake venoms and comparison between intraperitoneal and intravenous injection routes.

Scorpion stings and snake bites are major health hazards that lead to suffering of victims and high mortality. Thousands of injuries associated with such stings and bites of venomous animals occur every year worldwide. In North Africa, more than 100,000 scorpion stings and snake bites are reported annually. An appropriate determination of the 50% lethal doses (LD50) of scorpion and snake venoms appears to be an important step to assess (and compare) venom toxic activity. Such LD50 values are also commonly used to evaluate the neutralizing capacity of specific anti-venom batches. In the present work, we determined experimentally the LD50 values of reference scorpion and snake venoms in Swiss mice, and evaluated the influence of two main venom injection routes (i.e., intraperitoneal (IP) versus intravenous (IV)). The analysis of experimental LD50 values obtained with three collected scorpion venoms indicates that Androctonus mauretanicus (Am) is intrinsically more toxic than Androctonus australis hector (Aah) species, whereas the latter is more toxic than Buthus occitanus (Bo). Similar analysis of three representative snake venoms of the Viperidae family shows that Cerastes cerastes (Cc) is more toxic than either Bitis arietans (Ba) or Macrovipera lebetina (Ml) species. Interestingly, the venom of Elapidae cobra snake Naja haje (Nh) is far more toxic than viper venoms Cc, Ml and Ba, in agreement with the known severity of cobra-related envenomation. Also, our data showed that viper venoms are about three-times less toxic when injected IP as compared to IV, distinct from cobra venom Nh which exhibited a similar toxicity when injected IP or IV. Overall, this study clearly highlights the usefulness of procedure standardization, especially regarding the administration route, for evaluating the relative toxicity of individual animal venoms. It also evidenced a marked difference in lethal activity between venoms of cobra and vipers, which, apart from the nature of toxins, might be attributed to the rich composition of high molecular weight enzymes in the case of viper venoms.

Comparison between two methods of scorpion venom milking in Morocco.

BACKGROUND: The present study compared two methods used successfully in a large-scale program for the collection of scorpion venoms, namely the milking of adult scorpions via manual and electrical stimulation. RESULTS: Our immunobiochemical characterizations clearly demonstrate that regularly applied electrical stimulation obtains scorpion venom more easily and, most importantly, in greater quantity. Qualitatively, the electrically collected venom showed lack of hemolymph contaminants such as hemocyanin. In contrast, manual obtainment of venom subjects scorpions to maximal trauma, leading to hemocyanin secretion. Our study highlighted the importance of reducing scorpion trauma during venom milking. CONCLUSIONS: In conclusion, to produce high quality antivenom with specific antibodies, it is necessary to collect venom by the gentler electrical stimulation method.

Venomics and antivenomics profiles of North African Cerastes cerastes and C. vipera populations reveals a potentially important therapeutic weakness.

We report the proteomic analysis of the venom of the medically relevant snake, Cerastes cerastes, from Morocco, and the immunoreactivity profile of an experimental monospecific (CcMo_AV against Moroccan C. cerastes venom) and a commercial (Gamma-VIP against Tunisian C. cerastes and M. lebetina venoms) F(ab')(2) antivenoms towards geographic variants of C. cerastes and C. vipera venoms. The venom of C. cerastes is a low-complexity proteome composed of 25-30 toxins belonging to 6 protein families, mainly targetting the hemostatic system. This toxin arsenal explains the clinical picture observed in C. cerastes envenomings. Despite geographic compositional variation, the monospecific CcMo_AV and the Gamma-VIP divalent antivenom produced at Institut Pasteur de Tunis, showed similar immunocapturing capability towards Moroccan, Tunisian, and Egyptian C. cerastes venom proteins. Proteins partially escaping immunorecognition were all identified as PLA(2) molecules. Antivenomic analysis showed low degree of cross-reactivity of Moroccan CcMo_AV and Tunisian Gamma-VIP antivenoms towards C. vipera venom toxins. This study indicates that a more complete therapeutic cover could be achieved by including C. vipera venom in the formulation of venom immunization mixtures, thereby generating a pan-Cerastes antivenom.

Snake venomics of Macrovipera mauritanica from Morocco, and assessment of the para-specific immunoreactivity of an experimental monospecific and a commercial antivenoms.

Proteomic analysis of the venom of the medically relevant snake Macrovipera mauritanica from Morocco revealed a complex proteome composed of at least 45 toxins from 9 protein families targeting the hemostatic system of the prey or victim. The toxin profile of Moroccan M. mauritanica displays great similarity, but also worth noting departures, with the previously reported venom proteome of M. lebetina from Tunisia. Despite fine compositional differences between these Macrovipera taxa, their overall venom phenotypes explain the clinical picture observed in M. mauritanica and M. lebetina envenomings. However, M. mauritanica venom also contains significant amounts of orphan molecules whose presence in the venom seems to be difficult to rationalize in the context of a predator-prey arms race. The paraspecific immunoreactivity of an experimental monospecific (M. mauritanica) antivenom and a commercial bivalent antivenom, anti-C. cerastes and anti-M. lebetina, against the venoms of Moroccan M. mauritanica and Tunisian M. lebetina, was also investigated through an affinity chromatography-based antivenomics approach. Both antivenoms very efficiently immunodepleted homologous venom toxins and displayed a high degree of paraspecificity, suggesting the clinical utility of the two antivenoms for treating bites of both M. mauritanica or M. lebetina.