Our planet is home to around 600 venomous snake species, around 200 of which have toxins that can be deadly to humans. Yet scientists are now one step closer to the elusive goal of eventually developing a universal antivenom that could treat bites from all types of snakes.
In a paper published last month in Science Translational Medicine, researchers discussed a synthetic antibody designed to counteract an important group of neurotoxins in the venom of an entire family of snakes. Endemic to tropical and subtropical regions across the globe, Elapidae includes some of the world’s deadliest snakes, including king cobras and black mambas.
According to the World Health Organization (WHO), between 81,000 and 138,000 people die each year after being bitten by venomous snakes. An additional 400,000 are left with permanent disabilities from venom that targets the nervous system, blood, or various tissues. Yet research on snake bites has historically been lacking, leading the WHO to list it as a neglected tropical disease. Existing antivenoms haven’t changed much in decades. Most are derived from antibodies produced by animals (such as horses and sheep) that have been injected with snake venom.
Yet these antivenoms are sometimes woefully ineffective. Toxins vary among snake species, and victims aren’t always aware of which snake has bitten them. Furthermore, antivenom treatments contain a wide range of proteins based on the viruses and bacteria the antibody-producing animals’ immune systems previously fought off. Tragically, some people have experienced fatal anaphylaxis from antivenom treatment due to exposure to animal proteins.
The venom of elapids contains three-finger alpha-neurotoxins, which are responsible for causing paralysis in snake bite victims by shutting down a crucial protein related to movement. In the latest research, the scientists screened billions of artificial human antibodies to find the one that is best able to grasp the neurotoxin molecules and prevent them from harming muscle function. In lab tests on mice, the lab-made protein 95Mat5 was effective at neutralizing an otherwise-lethal venom from numerous different elapids, including monocled cobras, black mambas, and kraits (though not king cobras), even after a treatment delay of 20 minutes. The synthetic antivenom was approximately 15 times more effective than a conventional antivenom.
A big step forward for treating snake bites:
- This research effort was a collaboration between scientists from the Indian Institute of Science, the Liverpool School of Tropical Medicine, and the Scripps Research Institute.
- Using synthetic antibodies derived from human cell lines eliminates the risk of serious side effects from animal-derived antivenom and hopefully means that animals will not need to be subjected to snake venom to produce antivenom.
- Although approval for clinical trials is the next step, the ultimate goal would be to create a more universal antivenom by combining additional human antibodies that target other toxin groups into a single treatment.