Venom of the crotaline snake Atropoides nummifer (jumping viper) from Guatemala and Honduras: comparative toxicological characterization, isolation of a myotoxic phospholipase A(2) homologue and neutralization by two antivenoms

A comparative study was performed on the venoms of the crotaline snake Atro yoides nummifer from Guatemala and Honduras. SDS-polyacrylamide gel electro phoresis, under reducing conditions, revealed a highly similar pattern of t hese venoms, and between them and the venom of the same species from Costa Rica. Similar patterns were also observed in ion-exchange chromatography on CM-Shephadex C-25, in which a highly basic myotoxic fraction was present. This fraction was devoid of phospholipase A, activity and strongly reacted, by enzyme-immunoassay, with an antiserum against Bothrops asper myotoxin I I, a Lys-49 phospholipase A, homologue. A basic myotoxin of 16 kDa was isol ated to homogeneity from the venom of A. nummifer from Honduras, showing am ino acid composition and N-terminal sequence similar to those of Lys-49 pho spholipase Az variants previously isolated from other crotaline snake venom s. Guatemalan and Honduran A. nummifer venoms have a qualitatively similar toxicological profile, characterized by: lethal; hemorrhagic; myotoxic; ede ma-forming; coagulant; and defibrinating activities, although there were si gnificant quantitative variations in some of these activities between the t wo venoms, Neutralization of toxic activities by two commercially-available antivenoms in the region was studied. Polyvalent antivenom produced by Ins tituto Clodomiro Picado was effective in the neutralization of: lethal; hem orrhagic; myotoxic; coagulant; defibrinating; and phospholipase A(2) activi ties, but ineffective against edema-forming activity. On the other hand, MY N polyvalent antivenom neutralized: hemorrhagic; myotoxic; coagulant; defib rinating; and phospholipase A(2) activities, albeit with a lower potency th an Institute Clodomiro Picado antivenom. MYN antivenom failed to neutralize lethal and edema-forming activities of A. nummifer venoms. (C) 2001 Elsevi er Science Inc. All rights reserved.