A few years ago, the only FDA-approved coral snake antivenom in the United States got discontinued. The antidote was rarely used and expensive to make, so few companies had an interest in producing it. A new technique could cut the cost for making this and other antivenoms, and may make staying alive a little cheaper. Up until recently, the only way to make antivenom was to milk a snake of its venom, inject that venom into a horse and then harvest the antibodies that the horse produced. Those antibodies would be stored until it was time to inject them into an unlucky (or stupid) human who was bitten by a snake.
Now, scientists at the Butantan Institute in Brazil are developing a new, cheaper, easier method of making antivenom — specifically coral snake antivenom. They published their initial findings in the journal PLOS Neglected Tropical Diseases.
When the immune system encounters a toxin from venom, it searches for ways to bind to that toxin. The sites it binds to are called epitopes. The binding sites on the toxin are physical features, and are coded for in the snake's DNA. The scientists designed custom DNA strings that coded for these epitopes, and injected them into mice. This technique is called DNA vaccination, or genetic immunisation. Injecting a bit of genetic material inside a living body gets cells to produce the material the DNA codes for. The mice were producing antigens with the epitopes of coral snake venom, and then, in response, producing antibodies to fight those antigens.
There is one problem. The amount of antibodies the mice currently produce only neutralises 60 per cent of coral snake venom. The good news is that's up from the original 40 per cent — the mice were given "booster shots" which increased their production.
The researchers hope to eventually produce a 100 per cent effective venom. If they do, they will have eliminated the need for labs to keep both coral snakes and horses, making the process cheaper, faster, easier — and hopefully commercially viable. This could save a lot of people's lives, or just prevent them from having to spend days in the hospital on a ventilator because they got bitten.