We might be soon on the verge of having a super snake antivenom. In new research, a team of scientists says they’ve created a lab-made antibody geared to counteract toxic bites from a wide variety of snakes. In early tests with mice, the uber-antivenom appeared to work as intended.
Snake antivenom is typically derived from the antibodies of horses or other animals that produce a strong immune response to snake toxins. These donated antibodies can be highly effective at preventing serious injury and death from a snakebite, but they come with serious limitations.
The chemical makeup of one species’s toxin can vary significantly from another’s, for instance, so antibodies to one specific toxin provide little protection against others. Manufacturers can try to work around this by inoculating animals with several toxins at once, but this method has drawbacks, such as needing a higher dose of antivenom since only some of the antibodies will have any effect. These antivenom cocktails also raise the risk of side effects like serum sickness, which is an adverse immune response to the foreign antibodies. The antivenom industry as a whole has other systemic issues, particularly in parts of Africa where bites are a common threat.
These shortfalls mean that snakebites remain a very real danger, killing upwards of 100,000 people and injuring another 400,000 worldwide a year. But the authors of this new study, published Wednesday in Science Translational Medicine, say they’ve made an important step toward developing a holy grail of snakebite treatment: a universal antivenom.
The study was led by scientists at California-based Scripps Research. The team focused on a class of toxins called 3FTxs that are commonly used by venomous elapid snakes, a family of slithery reptiles that include cobras, mambas, and sea snakes. Though snake toxins are remarkably complex and different from one another, even within the same class, the team managed to find sections of these toxins that were pretty similar across different species.
The scientists produced a variety of 3FTx toxins in the lab and then screened them against a database of more than 50 billion synthetic antibodies, looking for ones that could potentially neutralize several toxins at once. After a few rounds of selection, they ultimately identified one antibody that seemed to broadly neutralize at least five different 3FTx variants, called 95Mat5. They then put the antibody to a real-life test, finding that it fully protected mice from dying from the toxins of the many-banded krait, Indian spitting cobra, and black mamba, in some cases better than conventional antivenom; it also offered some protection against venom from the king cobra.
“We were able to zoom in on the very small percentage of antibodies that were cross-reactive for all these different toxins,” said lead author Irene Khalek in a statement from Scripps. ‘This was only possible because of the platform we developed to screen our antibody library against multiple toxins in parallel.”
As seen with the king cobra, the 95Mat5 antibody alone may not work against every elapid snake. And it wouldn’t protect against bites from viper snakes, the other major family of venomous snakes. But the team’s process of identifying broadly neutralizing antibodies—adapted from similar research on the HIV virus—could be used to find other promising antivenom candidates. The researchers are already working to develop three other antibodies, one for elapid snakes and two for viper snakes. They envision a world where these can be blended together to someday soon create a 100% foolproof snakebite cure.
“We think that a cocktail of these four antibodies could potentially work as a universal antivenom against any medically relevant snake in the world,” said Khalek.