How do you make anti-venoms?
I was wondering how they produce antibodies from venoms of snakes to make a anti-venom from it. And whether this is a long process or not.
We put this question to Gavin Laing, of the Liverpool School of Tropical Medicine:Okay, antivenom has been around for at least 100 years, but the techniques of producing antivenom have not really altered a lot in that time. What normally happens is a very large animal is immunised over a long time with very small amounts of snake venom, so it won't harm the animal; traditionally they have used horses.Chris: So what you would do is milk the snake, get some of its venom and then inject that into the horse.Gavin: Yes, in very small quantities, so the horse will not be affected at all, it's only a tiny amount. The horse will then raise antibodies against this antigen that's been injected in the same way that humans immunised with smallpox would be raising antibodies against that.Chris: So the horse gets antibodies in the bloodstream.Gavin: That's correct, and over a long period of time, say eight months or so, the horse will then become hyper-immune. Every so often, some serum is then drawn from the horse and immunoglobulins are purified from that, and from that you can split the immunoglobulins into smaller components such as the FAB or the FAB prime-2. And these would then be infused intravenously to a person who presents themselves in hospital who has been envenomed.Chris: And so the antibodies would, in that victim, lock on to the venom and neutralise it?Gavin: They would. They would seek out the circulating venom in the patient and immobilise it. They would form an immune complex and would be completely harmless and would then be flushed away normally.You can read the whole interview with Gavin here, or listen to it as part of the podcast.