Opossum-based antidote to poisonous snake bites could save thousands of lives

Scientists will report in a presentation today that they have turned to the opossum to develop a promising new and inexpensive antidote for poisonous snake bites. They predict it could save thousands of lives worldwide without the side effects of current treatments. 

Worldwide, an estimated 421,000 cases of poisonous snake bites and 20,000 deaths from these bites occur yearly, according to the International Society on Toxicology. Intriguingly, opossums shrug off snake bite venom with no ill effects.

Claire F. Komives, Ph.D., who is at San Jose State University, explains that initial studies showing the opossum's immunity to snake venom were done in the 1940s. In the early 1990s, a group of researchers identified a serum protein from the opossum that was able to neutralize snake venoms. One researcher, B. V. Lipps, Ph.D., found that a smaller chain of amino acids from the opossum protein, called a peptide, was also able to neutralize the venom.

But Komives says it appears that no one has followed up on those studies to develop an antivenom therapy—at least not until she and her team came along. Armed with this information, they had the peptide chemically synthesized. When they tested it in venom-exposed mice, they found that it protected them from the poisonous effects of bites from U.S. Western Diamondback rattlesnakes and Russell's Viper venom from Pakistan.

The exact mechanism is not known, but recently published computer models have shown that the peptide interacts with proteins in the snake venom that are toxic to humans, she says. "It appears that the venom protein may bind to the peptide, rendering it no longer toxic."

Komives' team showed that they could program the bacteria E. coli to make the peptide. Producing the peptide in bacteria should enable the group to inexpensively make large quantities of it. The peptide should also be easy to purify from E. coli.