A comparison of ovine and equine antivenoms.

Commercial antivenoms produced in horses were compared with monospecific antivenoms raised in sheep against Crotalus durissus terrificus, Crotalus atrox, Crotalus adamanteus, Micrurus fulvius fulvius, Naja naja, Naja kaouthia, Echis ocellatus, Vipera lebetina deserti, Vipera berus berus and Vipera ammodytes ammodytes venom. Antibodies raised by immunizing sheep with C. d. terrificus venom were more effective than their equine counterparts in preventing lethal toxicity in mice (ED50), in inhibiting the venom's pharmacological effects (haemolysis, platelet aggregation and coagulation), and in neutralizing phospholipase A2 activity. Comparison of one ovine and three equine F(ab)2 products raised against V. a. ammodytes venom showed that all were at least 95% pure; that all protected mice; and that all contained antibody populations directed against most components of V. a. ammodytes and V. b. berus venoms. The ovine antivenoms generally contained a higher concentration of specific antibodies than the equine products. Finally, the ovine antivenoms raised against E. ocellatus, V. lebetina deserti, V. b. berus, M. f. fulvius and N. naja venoms provided better in vivo protection to mice than the equine antivenoms, but the equine antivenoms to N. kaouthia and C. atrox were more protective than the ovine product.