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Mass-vaccination against COVID-19 is still a distant goal for most low-to-middle income countries. The experience gained through decades producing polyclonal immunotherapeutics (such as antivenoms) in many of those countries is being redirected to develop similar products able to neutralize SARS-CoV-2 infection. In this study we analyzed the biological activity (viral neutralization or NtAb) and immunochemical properties of hyperimmune horses' sera (HHS) obtained during initial immunization (I) and posterior re-immunization (R) cycles using the RBD domain of the SARS-CoV-2 spike protein as antigen. HHS at the end of the R cycle showed higher NtAb titers when compared to those after the I cycle (35,585 vs. 7000 mean NtAb, respectively). Moreover, this increase paralleled an increase in avidity (95.2% to 65.2% mean avidity units, respectively). The results presented herein are relevant for manufacturers of these therapeutic tools against COVID-19.

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We developed experimental equine polyvalent and monovalent antivenoms against the venoms of Micrurus (M.) fulvius, M. nigrocinctus and M. surinamensis and studied their immunochemical reactivity on the venoms used as immunogens and on M. pyrrhocryptus, M altirostris and M. balyocoriphus venoms. Assessment of the neutralizing capacity of the polyvalent experimental antivenom was based on inhibition of lethality (preincubation and rescue assay experiments in mice) and indirect hemolytic and phospholipase activities. The immunochemical reactivity and neutralizing capacity were compared with those of two therapeutic antivenoms used for the treatment of coral snake envenomation in North America and in Argentina. In general, the experimental antivenom conferred a comparable level of neutralization against the venoms used as immunogens when compared to the therapeutic antivenoms and a certain level of cross-neutralization against the other venoms. The results suggest the need for additional venoms in the immunogenic mixture used, in order to obtain a broad spectrum anti-Micrurus antivenom with a good neutralizing potency. Paraspecific neutralization of South American coral snake venoms, although present at a higher level than the neutralization conferred by available nonspecific Micrurus therapeutic antivenoms, was rather low in relation to the specific neutralizing capacity.

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Envenomation by scorpions of the genus Tityus is an important public health problem in Argentina, involving near 8000 stings and 2 deaths each year. Treatment for envenomation is the use of specific antivenom and intensive hospital care. Antivenom is produced by the Ministry of Health and freely distributed throughout the country. For antivenom production it is necessary to collect scorpion venom, which is a difficult task because although scorpions can be found in Argentina, they are less abundant than in warmer latitudes. For this reason venom collection constitutes a bottleneck for antivenom production. Although in Argentina several species of Tityus can be found, most of the accidents are caused by Tityus trivittatus, and the venom of this scorpion has historically been the venom used for antivenom production. We analyzed retrospectively 26 pools of telson homogenates (6964 telsons) and 37 pools of milked venom obtained by electrical stimulation (equivalent to 6841 milkings). Lethal potencies of samples from different provinces were very similar, although venom from scorpions of Buenos Aires city showed the lowest potency. The venom obtained by milking (median LD50 12.3 µg), provided batches containing LD50s more potent when compared with the venom obtained from telson homogenates (p < 0.0001). Many batches of telson homogenates (30%) showed lower potencies than acceptable for antivenom production and control. In addition to the study of the venom yield, the records of immunization of horses, the potency of the batches and the protein content of each batch of anti-scorpion antivenom produced were analyzed, comparing those produced using milked venom with those using telson homogenates as immunogens. Batches produced using milked venom required a shorter period of immunization (p < 0.0001), rendered higher neutralizing titers (p 0.0350) and possessed lower protein content (p 0.0092). Results clearly showed that the milking of scorpions is a more efficient tool to obtain venom for antivenom production in comparison to the use of telson homogenates.

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Strains of Shiga toxin-producing Escherichia coli (STEC) can cause the severe Hemolytic Uremic Syndrome (HUS). Shiga toxins are protein toxins that bind and kill microvascular cells, damaging vital organs. No specific therapeutics or vaccines have been licensed for use in humans yet. The most common route of infection is by consumption of dairy or farm products contaminated with STEC. Domestic cattle colonized by STEC strains represent the main reservoir, and thus a source of contamination. Outer Membrane Vesicles (OMV) obtained after detergent treatment of gram-negative bacteria have been used over the past decades for producing many licensed vaccines. These nanoparticles are not only multi-antigenic in nature but also potent immunopotentiators and immunomodulators. Formulations based on chemical-inactivated OMV (OMVi) obtained from a virulent STEC strain (O157:H7 serotype) were found to protect against pathogenicity in a murine model and to be immunogenic in calves. These initial studies suggest that STEC-derived OMV has a potential for the formulation of both human and veterinary vaccines.

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Injuries caused by venomous animals affect vast areas of Latin America, Southern Asia, Southeast Asia, sub-Saharan Africa, and Oceania, and pose a serious problem for global public health. Based on an analysis of the current panorama of global production of ophidian and arachnid antivenoms, it is concluded that they are semi-orphaned products. This is a favorable scenario in which to strengthen public laboratory production. Governments should make a political decision in this regard in the interest of equity in population health. In the Region of the Americas, these actions could be part of a program led by the Pan American Health Organization to ensure the availability of these biologicals in strategically located health centers. Twelve public facilities producing antivenoms have been identified in the Region, including Brazil and Mexico, which are the biggest public producers. These laboratories should be managed like industrial operations that produce tangible goods without ignoring strategic planning. National regulatory authorities should help the public laboratories that produce them by providing necessary technical assistance and consultancy without any loss of impartiality or rigor in the evaluation of their quality management systems. New superior production technologies using hyperimmune mammalian plasma are in the experimental phase; no information on its production has been found in the literature.

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Los accidentes causados por animales ponzoñosos afectan vastas zonas de América Latina, Sur de Asia, Sudeste Asiático, África subsahariana y Oceanía y representan un serio problema para la salud pública mundial. A partir de un análisis del panorama actual en materia de producción global de los antivenenos ofídicos y aracnídicos, se concluye que son productos semi-huérfanos. Esta situación plantea un escenario favorable para fortalecer su producción por parte de los laboratorios públicos. Los gobiernos deberán tomar una decisión política al respecto en aras de la equidad en la salud de la población. En la Región de las Américas, estas acciones podrían enmarcarse en un programa liderado por la Organización Panamericana de la Salud, para garantizar la disponibilidad de estos productos biológicos en centros asistenciales estratégicamente localizados. Se han identificado 12 establecimientos públicos productores de antivenenos en la Región entre los cuales los de Brasil y México son los mayores productores públicos. La gestión de estos laboratorios debe ser la propia de una organización industrial productora de bienes tangibles que no soslaye la planificación estratégica. Las autoridades regulatorias nacionales deberían ayudar a los laboratorios públicos que los producen prestándoles asesoramiento y consultoría sin perder la imparcialidad ni el rigor necesarios en la evaluación de sus sistemas de gestión de la calidad. Las nuevas tecnologías superiores de la producción a partir de plasma hiperinmune de mamíferos se encuentran en fase experimental. No se ha encontrado en la bibliografía información sobre su incorporación en las líneas de producción.

Injuries caused by venomous animals affect vast areas of Latin America, Southern Asia, Southeast Asia, sub-Saharan Africa, and Oceania, and pose a serious problem for global public health. Based on an analysis of the current panorama of global production of ophidian and arachnid antivenoms, it is concluded that they are semi-orphaned products. This is a favorable scenario in which to strengthen public laboratory production. Governments should make a political decision in this regard in the interest of equity in population health. In the Region of the Americas, these actions could be part of a program led by the Pan American Health Organization to ensure the availability of these biologicals in strategically located health centers. Twelve public facilities producing antivenoms have been identified in the Region, including Brazil and Mexico, which are the biggest public producers. These laboratories should be managed like industrial operations that produce tangible goods without ignoring strategic planning. National regulatory authorities should help the public laboratories that produce them by providing necessary technical assistance and consultancy without any loss of impartiality or rigor in the evaluation of their quality management systems. New superior production technologies using hyperimmune mammalian plasma are in the experimental phase; no information on its production has been found in the literature.

Os acidentes causados por animais peçonhentos se distribuem por vastas áreas da América Latina, sul da Ásia, Sudeste Asiático, África subsaariana e Oceania, representando um sério problema à saúde pública mundial. A partir de uma análise do panorama atual da produção mundial de soros antiofídicos e antiaracnídeos se concluiu que são produtos semiórfãos. Tal situação cria um cenário favorável para estimular a produção destes produtos por laboratórios públicos. Os governos devem tomar uma decisão política neste sentido para assegurar a equidade em saúde da população. Na Região das Américas, as ações poderiam englobar um programa encabeçado pela Organização Pan-Americana da Saúde para garantir a disponibilidade dos produtos biológicos em centros de atenção estrategicamente localizados. Existem 12 instituições públicas que produzem soros antivenenos na Região, sendo que os maiores produtores estão no Brasil e no México. Estes laboratórios devem ser geridos como uma indústria produtora de bens tangíveis sujeita a um planejamento estratégico. Os órgãos reguladores nacionais devem auxiliar os laboratórios públicos prestando assessoria e consultoria com a imparcialidade e o rigor necessários para avaliar a gestão da qualidade. Novas tecnologias avançadas de produção de soro baseadas em plasma hiperimune de mamíferos estão em fase experimental. Não há informação na literatura sobre a inclusão destas tecnologias nas linhas de produção.

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Snake venom toxicity is the consequence of a combination of peptides and proteins whose identification and characterization are of great importance to understand envenomation and develop new clinical treatments. The Elapinae subfamily includes coral snakes whose bite causes mainly neurotoxic effects which disable muscle contraction and paralyse the heart as well as inhibit respiration. However, the structure-function relationship of venom toxins has been investigated only for a few species. We herein study biological aspects of the Micrurus pyrrhocryptus venom such as LD(50), hemorrhagic, necrotic, coagulant, myotoxic and hemolytic activity as well as the ability of venom components to compete with alpha-Bungarotoxin for the ligand-binding site of the nicotinic acetylcholine receptor. Besides, we report the determination of the molecular mass and N-terminal sequence of toxins including PLA2s, short, long and weak neurotoxins. The complete sequence of one of the short neurotoxins has also been obtained, this being the first sequence of an alpha-neurotoxin determined in the M. pyrrhocryptus venom and one of the few fully determined in members of the Micrurus genus.

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Bites by Loxosceles (L.) laeta spiders can produce severe envenomation in humans. The only specific treatment is the early administration of antivenom. The production of anti-Loxosceles antivenom is hampered by the extremely low venom yield by these spiders and by the difficulties in maintaining a large breeder of Loxosceles. We developed an experimental equinum L. laeta antivenom, using as immunogen venom glands homogenates from spiders captured in Argentina. Horses immunized with venom gland homogenate (1.0 mg total protein per horse) by the subcutaneous route were bled after completion of the immunization scheme. Plasma was fractionated by ammonium sulfate precipitation and treated with pepsin to obtain F(ab')2 fragments. The protein composition of the experimental antivenom was assessed by SDS-PAGE, and its immunochemical reactivity was compared with those of other anti-Loxosceles antivenoms available for therapeutic use in Argentina by ELISA and Western blot. The experimental, homologous anti-L. laeta antivenom appeared to be more efficient in neutralizing the lethal potency in mice and the necrotizing activity in rabbits than of the heterologous antivenom.

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