Universal antidote to deadly snake venoms found

Although current treatments for snake venom poisoning are quite advanced, it is necessary to first identify the species of snake that bit a person in order to find the right antidote. But thanks to a new study by an international team of scientists, this will soon not have to be done. They have developed a universal antibody that neutralizes the deadly venom of cobras, krait snakes and mambas and could potentially save tens of thousands of lives each year.

Poisoning due to snakebites is recognized as a serious global public health problem. According to various estimates (however, most of them are somewhat overestimated), up to 138,000 people die each year from snake bites, and more than 400,000 more remain disabled. People in Africa and Asia are mostly affected, not only because of the high number of snakebite cases, but also because of limited access to adequate medical care.

Improved treatment methods are urgently needed to address this problem. Today, control of fatal snake venom poisoning requires accurate identification of the species of snake that has bitten a person in order to select a suitable antidote. However, even in this case, complications in the form of serum sickness and anaphylaxis - an allergic reaction of the body to the presence in the blood of a foreign protein antidote, which is often of animal origin, are not excluded.

Therefore, an international group of researchers from the US, UK and India decided to create a universal antidote to the deadly venom of snakes of the family Elapidae (Aspidae). This vast family includes 384 species of venomous snakes, including the most dangerous: the king cobra, the black mamba and the Indian krait. The scientists reported their development in a paper published in the journal Science Translational Medicine.

The researchers first isolated and compared the venom proteins of different aspids. They found that a type of protein called three-finger toxin (3FTx) is present in all aspid snakes and contains small regions that are similar in different species. In addition, 3FTx proteins are considered highly toxic and cause whole-body paralysis, making them an ideal therapeutic target.

To find the antibody that blocks 3FTx and is least likely to cause an allergic reaction, biologists studied a library of more than 50 billion different human antibodies. They tested which ones best bind to different variants of the 3FTx protein. In this way, they were able to narrow the search to 30 antibodies, of which only one stood out as having the strongest interaction with the venom toxin - the 95Mat5 antibody.

The scientists then tested the effect of fully synthetic 95Mat5 on mice injected with toxins of the South China multibanded krait, monocle cobra, black mamba and king cobra. In all cases, the rodents that were simultaneously injected with 95Mat5 were protected not only from death, but also from paralysis and any other complications. When the researchers investigated why 95Mat5 was so effective in blocking different variants of 3FTx, they found that the antibody mimics the structure of the human protein to which 3FTx normally binds, causing muscle paralysis.

While 95Mat5 is effective against the venom of all aspids, it does not block the venom of vipers, the second broad family of venomous snakes. In the future, the authors of the paper plan to find broadly neutralizing antibodies against another aspid toxin, as well as two toxins found in viper venom. According to the researchers, combining 95Mat5 with three other antibodies could potentially work as a universal antidote against any snake in the world.