Comparison of Phylogeny, Venom Composition and Neutralization by Antivenom in Diverse Species of Bothrops Complex
Figure 8
Neutralizing ability of Bothrops antivenom (SAB) against the major toxic activities of Bothropoides jararaca and Bothrops atrox venoms.
In the neutralization assays, the Bothrops atrox venom was pooled from 8 adult snakes collected in FLONA Tapajós, Santarém, Pará, Brazil. For the neutralization of lethality and hemorrhagic activity, doses of B. jararaca or B. atrox venoms were pre-incubated with SAB at ratios of 1, 2 or 4 times the SAB volume required to neutralize an equal amount of reference venom according to the manufacturer. To assess hemorrhage, 10 µg was incubated and injected intradermically in the dorsum of a group of 5 mice. The results show the % neutralization of the mean values, taken as 100% activity, of the data obtained after injection with venom incubated with saline. For the neutralization of lethal activity, 3 LD50 doses of B. jararaca (105 µg) or B. atrox (225 µg) venom were incubated, and the mixtures were injected intraperitoneally into groups of 5 mice; lethality was recorded over a period of 48 hours. The results represent the values obtained in 3 independent experiments and are expressed as % neutralization, considering the number of live/dead mice after this period. To assess the neutralization of coagulant activity, a constant amount of venom (2 times the minimum coagulant concentrations) was incubated with several dilutions of antivenom; the mixture was added to 100 µl bovine plasma, and the clotting times were recorded using a model ST4 mechanical coagulometer (Diagnostica Stago). The neutralization was expressed as the effective dose (ED), defined as the antivenom/venom ratio at which the clotting time was increased threefold when compared to the clotting time of plasma incubated with venom alone.