Venomics and antivenomics of the poorly studied Brazil's lancehead, Bothrops brazili (Hoge, 1954), from the Brazilian State of Pará

The Brazil's lancehead, Bothrops brazili, is a poorly studied pit viper distributed in lowlands of the equatorial rainforests of southern Colombia, northeastern Peru, eastern Ecuador, southern and southeastern Venezuela, Guyana, Suriname, French Guiana, Brazil, and northern Bolivia. Few studies have been reported on toxins isolated from venom of Ecuadorian and Brazilian B. brazili. The aim of the present study was to elucidate the qualitative and quantitative protein composition of B. brazili venom from Pará (Brazil), and to carry out a comparative antivenomics assessment of the immunoreactivity of the Brazilian antibothropic pentavalent antivenom [soro antibotrópico (SAB) in Portuguese] against the venoms of B. brazili and reference species, B. jararaca. Methods: We have applied a quantitative snake venomics approach, including reverse-phase and two-dimensional electrophoretic decomplexation of the venom toxin arsenal, LC-ESI-MS mass profiling and peptide-centric MS/MS proteomic analysis, to unveil the overall protein composition of B. brazili venom from Pará (Brazil). Using third-generation antivenomics, the specific and paraspecific immunoreactivity of the Brazilian SAB against homologous (B. jararaca) and heterologous (B. brazili) venoms was investigated. Results: The venom proteome of the Brazil's lancehead (Pará) is predominantly composed of two major and three minor acidic (19%) and two major and five minor basic (14%) phospholipase A2 molecules; 7-11 snake venom metalloproteinases of classes PI (21%) and PIII (6%); 10-12 serine proteinases (14%), and 1-2 L-amino acid oxidases (6%). Other toxins, including two cysteine-rich secretory proteins, one C-type lectin-like molecule, one nerve growth factor, one 5'-nucleotidase, one phosphodiesterase, one phospholipase B, and one glutaminyl cyclase molecule, represent together less than 2.7% of the venom proteome. Third generation antivenomics profile of the Brazilian pentabothropic antivenom showed paraspecific immunoreactivity against all the toxin classes of B. brazili venom, with maximal binding capacity of 132.2 mg venom/g antivenom. This figure indicates that 19% of antivenom's F(ab')2 antibodies bind B. brazili venom toxins. Conclusion: The proteomics outcome contribute to a deeper insight into the spectrum of toxins present in the venom of the Brazil's lancehead, and rationalize the pathophysiology underlying this snake bite envenomings. The comparative qualitative and quantitative immunorecognition profile of the Brazilian pentabothropic antivenom toward the venom toxins of B. brazili and B. jararaca (the reference venom for assessing the bothropic antivenom's potency in Brazil), provides clues about the proper use of the Brazilian antibothropic polyvalent antivenom in the treatment of bites by the Brazil's lancehead.(AU)

A biodistribution study of Hemiscorpius lepturus scorpion venom and available polyclonal antivenom in rats

The purpose of the present study was to investigate the biodistribution profile of the venom of Hemiscorpius lepturus, the most dangerous scorpion in Iran. Blood and tissue samples were taken at various predetermined intervals during a 400-minute period for the venom and a 360-minute period for the antivenom in rats. The radio-iodination was carried out using the chloramine-T method. The results showed that the descending order of venom uptake was skin, kidneys and intestine, respectively. The descending order of polyclonal antivenom uptake was kidneys, intestine, heart and lungs. The calculated pharmacokinetic parameters of the venom were Telimination half-life = 521.5 ± 12.6 minutes; Vd/F (apparent volume of distribution) = 14.9 ± 3.3 mL; clearance (CL/F, apparent total clearance of the drug from plasma) 0.02 ± 0.005 mL/minute and for the antivenom Telimination half-life = 113.7 ± 7.4 minutes; Vd/F = 13 ± 1.2 mL and CL/F 0.08 ± 0.01 mL/minute. The pharmacokinetics profile comparison of the venom with that of the antivenom shows that serotherapy may be more effective if administered within 2-4 hours following envenomation by H. lepturus.(AU)