as a Therapeutic Agent to Counteract the Effects of VX Toxicity in Domestic Swine

The efficacy of a recombinant human butyrylcholinesterase (rBChE) in protecting against topically administered VX was examined in anaesthetized domestic swine. Animals exposed to 2LD50 of VX showed signs of organophosphate poisoning and died within 2—3 hours. When a single dose of rBChE was administered 15 min post VX exposure, survival times increased but the animals died before the end of the six-hour test period. In an attempt to increase the effectiveness of rBChE, the dose was administered in 5 equal portions at various times post-agent. The animals survived with little or no signs of poisoning. Using this multiple rBChE dosing regimen, animals were monitored for 7 days following VX exposure. The VX exposed and rBChE treated animals were compared to swine that received rBChE only or were exposed to VX and treated with the current standard of treatment for nerve agent poisoning: 2PAM and atropine. Animals were monitored for clinical signs, body weight and cognitive function. Blood samples were taken to determine biochemistry, electrolytes and cholinesterase levels. None of the surviving animals displayed any sign of cognitive impairment, moreover no hematological or chemical abnormalities were observed. These results demonstrated that rBChE was effective in protecting the animals against a lethal dose of VX