Snake venomics of Lachesis muta rhombeata and genus-wide antivenomics assessment of the paraspecific immunoreactivity of two antivenoms evidence the high compositional and immunological conservation across Lachesis.

We report the proteomic analysis of the Atlantic bushmaster, Lachesis muta rhombeata, from Brazil. Along with previous characterization of the venom proteomes of L. stenophrys (Costa Rica), L. melanocephala (Costa Rica), L. acrochorda (Colombia), and L. muta muta (Bolivia), the present study provides the first overview of the composition and distribution of venom proteins across this wide-ranging genus, and highlights the remarkable similar compositional and pharmacological profiles across Lachesis venoms. The paraspecificity of two antivenoms, produced at Instituto Vital Brazil (Brazil) and Instituto Clodomiro Picado (Costa Rica) using different conspecific taxa in the immunization mixtures, was assessed using genus-wide comparative antivenomics. This study confirms that the proteomic similarity among Lachesis sp. venoms is mirrored in their high immunological conservation across the genus. The clinical and therapeutic consequences of genus-wide venomics and antivenomics investigations of Lachesis venoms are discussed. BIOLOGICAL SIGNIFICANCE: The proteomics characterization of L. m. rhombeata venom completes the overview of Lachesis venom proteomes and confirms the remarkable toxin profile conservation across the five clades of this wide-ranging genus. Genus-wide antivenomics showed that two antivenoms, produced against L. stenophrys or L. m. rhombeata, exhibit paraspecificity towards all other congeneric venoms. Our venomics study shows that, despite the broad geographic distribution of the genus, monospecific antivenoms may achieve clinical coverage for any Lachesis sp. envenoming.

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.

Preclinical assessment of the neutralizing capacity of antivenoms produced in six Latin American countries against medically-relevant Bothrops snake venoms.

Species of the genus Bothrops induce the vast majority of snakebite envenomings in Latin America. A preclinical study was performed in the context of a regional network of public laboratories involved in the production, quality control and development of antivenoms in Latin America. The ability of seven polyspecific antivenoms, produced in Argentina, Brazil, Peru, Bolivia, Colombia and Costa Rica, to neutralize lethal, hemorrhagic, coagulant, defibrinogenating and myotoxic activities of the venoms of Bothrops neuwiedi (diporus) (Argentina), Bothrops jararaca (Brazil), B. neuwiedi (mattogrossensis) (Bolivia), Bothrops atrox (Peru and Colombia) and Bothrops asper (Costa Rica) was assessed using standard laboratory tests. Despite differences in the venom mixtures used in the immunization of animals for the production of these antivenoms, a pattern of extensive cross-neutralization was observed between these antivenoms and all the venoms tested, with quantitative differences in the values of effective doses. This study reveals the capacity of these antivenoms to neutralize, in preclinical tests, homologous and heterologous Bothrops venoms in Central and South America, and also highlight quantitative differences in the values of Median Effective Doses (ED50s) between the various antivenoms.

Assessment of the impact of solvent/detergent treatment on the quality and potency of a whole IgG equine antivenom.

We have evaluated for the first time the impact of a solvent/detergent (S/D) treatment on the quality and in vivo neutralization potency of horse-derived whole IgG antivenom used in the treatment of viperid snake bite envenoming in Central America. The S/D treatment by 1% tri (n-butyl) phosphate (TnBP) - 1% Triton X-45 at 22-25 degrees C was applied either on starting plasma or on purified immunoglobulins. The S/D agents were removed from both fractions by extractions with oil. S/D-treated plasma was subjected to caprylic acid precipitation to purify the immunoglobulins. Products were formulated, sterile-filtered, and filled into 10-mL vials, stored at 5+/-3 degrees C, and subjected to routine quality controls, SDS-PAGE, determination of anti-Bothrops asper venom antibody titre by ELISA, in vivo B. asper venom-neutralization potency tests, and safety test, comparatively with an antivenom manufactured by caprylic acid fractionation without S/D treatment. Results indicate that these conditions of S/D treatment on purified immunoglobulin yielded an antivenom of high turbidity that induced weight loss in animals. In contrast, antivenom fractionated from the S/D-treated plasma had physico-chemical and biological characteristics indistinguishable from those of the non-S/D-treated antivenom. S/D treatment of horse plasma may be considered to increase the viral safety of antivenoms.

Immunization with native and cobalt 60-irradiated Crotalus durissus terrificus venom in swiss mice: assessment of the neutralizing potency of antisera

ELISA was used to evaluate, follow, and compare the humoral immune response of Swiss mice during hyperimmunization with natural and Cobalt 60-irradiated (60Co) Crotalus durissus terrificus venom. Potency and neutralization were evaluated by in vitro challenges. After hyperimmunization, immunity was observed by “in vivo” challenge and the side effects were assessed. The animals immunization with one LD50 of the venom was on days one, 15, 21, 30, and 45, when blood samples were collected; the challenges occurred on the 60th day. Results showed that ELISA was efficient in evaluating, following, and comparing mouse immune response during hyperimmunization. Serum titers produced with natural venom were similar to those produced with irradiated venom. Immunogenic capacity was maintained after 60Co irradiation. Serum produced from Crotalus durissus terrificus irradiated venom showed higher potency and neutralization capacity than that from natural venom. All antibodies were able to neutralize five LD50 from these venoms. Clinical alterations were minimum during hyperimmunization with irradiated venom