Snake Venomics of the Lesser Antillean Pit Vipers Bothrops caribbaeus and Bothrops lanceolatus: Correlation with Toxicological Activities and Immunoreactivity of a Heterologous Antivenom

Abstract

The venom proteomes of the snakes Bothrops caribbaeus and Bothrops lanceolatus, endemic to the Lesser Antillean islands of Saint Lucia and Martinique, respectively, were characterized by reversephase HPLC fractionation, followed by analysis of each chromatographic fraction by SDS-PAGE, N-terminal sequencing, MALDI-TOF mass fingerprinting, and collision-induced dissociation tandem mass spectrometry of tryptic peptides. The venoms contain proteins belonging to seven (B. caribbaeus) and five (B. lanceolatus) types of toxins. B. caribbaeus and B. lanceolatus venoms contain phospholipases A2, serine proteinases, L-amino acid oxidases and zinc-dependent metalloproteinases, whereas a long disintegrin, DC-fragments and a CRISP molecule were present only in the venom of B. caribbaeus, and a C-type lectin-like molecule was characterized in the venom of B. lanceolatus. Compositional differences between venoms among closely related species from different geographic regions may be due to evolutionary environmental pressure acting on isolated populations. The venoms of these two species differed in the composition and the relative abundance of their component toxins, but they exhibited similar toxicological and enzymatic profiles in mice, characterized by lethal, hemorrhagic, edemaforming, phospholipase A2 and proteolytic activities. The venoms of B. caribbaeus and B. lanceolatus are devoid of coagulant and defibrinogenating effects and induce only mild local myotoxicity in mice. The characteristic thrombotic effect described in human envenomings by these species was not reproduced in the mouse model. The toxicological profile observed is consistent with the abundance of metalloproteinases, PLA2s and serine proteinases in the venoms. A polyvalent (Crotalinae) antivenom produced in Costa Rica was able to immunodeplete ∼80% of the proteins from both B. caribbaeus and B. lanceolatus venoms, and was effective in neutralizing the lethal, hemorrhagic, phospholipase A2 and proteolytic activities of these venoms