Antivenomics and in vivo preclinical efficacy of six Latin American antivenoms towards south-western Colombian Bothrops asper lineage venoms
Authors: Mora-Obando Diana , Pla Davinia , Lomonte Bruno , Guerrero-Vargas Jimmy Alexander , Ayerbe Santiago , Calvete Juan J. 
Published: February 2021

Background

Bothrops asperrepresents the clinically most important snake species in Central America and Northern South America, where it is responsible for an estimated 50–80% of snakebites. Compositional variability among the venom proteomes ofB.asperlineages across its wide range mirrors clinical differences in their envenomings. Bothropic antivenoms generated in a number of Latin American countries commonly exhibit a certain degree of paraspecific effectiveness in the neutralization of congeneric venoms. Defining the phylogeographic boundaries of an antivenom's effectivity has implications for optimizing its clinical use. However, the molecular bases and impact of venom compositions on the immune recognition and neutralization of the toxic activities of across geographically disparate populations ofB.asperlineages has not been comprehensively studied.

Methodology/Principal findings

Third-generation antivenomics was applied to quantify the cross-immunorecognizing capacity against the individual components of venoms of threeB.asperlineages (B.asper(sensu stricto),B.ayerbeiandB.rhombeatus) distributed in south-western (SW) Colombia, of six Latin American antivenoms, produced against homologous (Colombia, INS-COL and PROBIOL) and Costa Rica (ICP)), and heterologous (Argentina (BIOL), Perú (INS-PERU) and Venezuela (UCV)) bothropic venoms.In vivoneutralization assays of the lethal, hemorrhagic, coagulant, defibrinogenating, myotoxic, edematogenic, indirect hemolytic, and proteolytic activities of the three SW ColombianB.asperlineage venoms were carried to compare the preclinical efficacy of three (Colombian INS-COL and PROBIOL, and Costa Rican ICP) antivenoms frequently used in Colombia. Antivenomics showed that all the six antivenom affinity matrices efficiently immunoretained most of theB.asperlineages venom proteins and exhibited impaired binding towards the venoms' peptidomes. The neutralization profile of the INS-COL, PROBIOL and ICP antivenoms towards the biological activities of the venoms of SW ColombianB.asper(sensu stricto),B.ayerbeiandB.rhombeatuslineages was coherent with the antivenomics outcome. In addition, the combination ofin vitro(antivenomics) andin vivoneutralization results allowed us to determine their toxin-specific and venom neutralizing antibody content. Noteworthy, heterologous INS-PERU, BIOL, and UCV bothropic antivenoms had equal or higher binding capacity towards the venoms components of SW ColombianB.asperlineages that the homologous Colombian and Costa Rican antivenoms.

Conclusions/Significance

The combinedin vitroandin vivopreclinical outcome showed that antivenoms manufactured in Colombia and Costa Rica effectively neutralize the major toxic activities of SW ColombianB.asperlineage venoms. The antivenomics profiles of the heterologous antivenoms manufactured in Argentina, Venezuela, and Perú strongly suggests their (pre)clinical adequacy for the treatment ofB.asperlineage envenomings in SW Colombia. However, their recommendation in the clinical setting is pending onin vivoneutralization testing and clinical testing in humans.Bothrops asperis a highly adaptable snake species complex, which is considered the most dangerous snake throughout much of its distribution range from the Atlantic lowland of eastern México to northwestern Perú. Antivenoms are the only scientifically validated treatment of snakebite envenomings. Venom variation is particularly common in wide ranging species, such asB.asper, and may result in variable clinical presentations of envenomings, as is the case for theB.asperspecies complex, potentially undermining the efficacy of snakebite treatments depending on the immunization mixture used in the generation of the antivenom. Conversely, phylogenetic conservation of antigenic determinants confers an unpredictable degree of paraspecificity to homologous antivenoms produced for a geographic area, but also to heterologous congeneric antivenoms, towards the venom components of allopatric conspecific populations. This work aimed at comparing the preclinical profile of a panel of Latin American homologous and heterologous antivenoms against the venoms ofB.asperlineages distributed in SW Colombia. The outcome of this study strongly suggests the suitability of considering the heterologous antivenoms BIOL (Argentina), UCV (Venezuela) and INS-PERU (Perú) as alternatives to homologous Colombian INS-COL and PROBIOL and Costa Rican ICP antivenoms for the treatment of envenomings byB.asper(sensu stricto) in W Colombia and Ecuador,B.ayerbeiin Cauca and Nariño (Colombia), andB.rhombeatusin Cauca river valley, SW Colombia.