Commercial Antivenoms Exert Broad Paraspecific Immunological Binding and In Vitro Inhibition of Medically Important Bothrops Pit Viper Venoms

Abstract

Snakebite envenoming is a life threatening neglected tropical disease that represents a considerable public health concern in the tropics. Viperid snakes of the genus Bothrops are among those of greatest medical importance in Latin America, and they frequently cause severe systemic haemotoxicity and local tissue destructive effects in human victims. Although snakebite antivenoms can be effective therapeutics, their efficacy is undermined by venom toxin variation among snake species. In this study we investigated the extent of paraspecific venom cross-reactivity exhibited by three distinct anti-Bothrops antivenoms (Soro antibotrópico-crotálico, BothroFav and PoliVal-ICP) against seven different Bothrops pit viper venoms from across Latin America. We applied a range of in vitro assays to assess the immunological binding and recognition of venom toxins by the antivenoms and their inhibitory activities against specific venom functionalities. Our findings demonstrated that, despite some variations, the monovalent antivenom BothroFav and the polyvalent antivenoms Soro antibotrópico-crotálico and PoliVap-ICP exhibited extensive immunological recognition of the distinct toxins found in the different Bothrops venoms, with Soro antibotrópico-crotálico generally outperformed by the other two products. In vitro functional assays revealed outcomes largely consistent with the immunological binding data, with PoliVap-ICP and BothroFav exhibiting the greatest inhibitory potencies against procoagulant and fibrinogen-depleting venom activities, though Soro antibotrópico-crotálico exhibited potent inhibition of venom metalloproteinase activities. Overall, our findings demonstrate broad levels of antivenom paraspecificity, with in vitro immunological binding and functional inhibition often highly comparable between venoms used to manufacture the antivenoms and those from related species, even in the case of the monovalent antivenom BothroFav. Our findings suggest that the current clinical utility of these antivenoms could possibly be expanded to other parts of Latin America that currently suffer from a lack of specific snakebite therapies.

Increased Binding of von Willebrand Factor to Sub-Endothelial Collagen May Facilitate Thrombotic Events Complicating Bothrops lanceolatus Envenomation in Humans

“…Third-generation antivenomics analysis has further proven Bothrofav’s high neutralizing efficacy of all the major immunogenic protein components of B. lanceolatus venom (i.e., metalloproteinases, phospholipases A 2 , serine proteinases, C-type lectin-like proteins, and disintegrins), with the exception of poor immunogenic peptides [ 63 ]. In our study, the Bothrovav-induced prevention of the inhibitory effects of B. lanceolatus venom on vWF collagen type I and type III binding may be related to the reported beneficial effects of the antivenom on coagulopathic activities [ 64 , 65 ].…”

In vitro immunoreactivity and in vivo neutralization of Trimeresurus gracilis venom with antivenoms targeting four pit viper species

“…Commercial antivenoms may exert broad paraspecific immunological binding and neutralization of medically important snake venoms such as in Bothrops [ 38 ]. Sousa et al [ 39 ] compared the composition and reactivity with multispecific Bothrops antivenom (SAB) of venoms collected from six species of Bothrops , Bothropoides and Rhinocerophis snakes, and found that P-III SVMPs are the most antigenic toxins in the venoms of snakes from the Bothrops complex, while class P-I SVMPs, SVSPs and PLA 2 s reacted with SAB in lower levels.…”

“…The impact of variation across ELISA plates has been minimized because we implemented measures include maintaining a consistent reaction time and temperature, using identical batch numbers for ELISA plates, employing the same ELISA reader, and ensuring the consistent participation of the same experimenter. (4) As the venom samples from each species are pooled from individual snakes, we refrained from testing differences among treatments using t-tests, ANOVA, or nonparametric statistics, as observed in other studies (such as [ 29 , 30 , 38 , 42 , 43 , 45 , 46 ]). For future studies, venom samples from different individuals, populations, or geographical areas can be employed and compared in relevant experiments to enable statistical testing among treatments.…”

“…(2) A rescue experiment, as conducted in [42], which more closely simulates a real envenomation case than the preincubation neutralization experiment, was not carried out in our study. However, it is noteworthy that a majority of relevant studies (such as [30,38,39,41,[43][44][45][46]) commonly employ the latter design. We opted for preincubation neutralization experiments in our research to facilitate comparisons with other studies.…”

Bothrops lanceolatus Envenoming in Martinique: A Historical Perspective of the Clinical Effectiveness of Bothrofav Antivenom Treatment

“…Likewise, hibernation, the recency of last venom extraction, and temperature participate in the great variability in venom composition within a population [ 25 , 26 , 27 , 28 ]. Consequently, for human envenoming, venom variation may result in significant differences in symptoms arising from snake bites and innate mechanisms initiating inflammatory reactions critical to host protection and can also undermine the efficacy of the antivenom, which may have a reduced potential to neutralize such a variety of different toxins [ 29 , 30 , 31 ]. Although venom variation and the host response might have been different during the two periods of Bothrofav use, it is very unlikely that these changes explain the periods free of complications following Bothrofav’s initial production and renewal.…”