'Unparalleled' snake antivenom made from man bitten 200 times

The blood of a US man who deliberately injected himself with snake venom for nearly two decades has led to an "unparalleled" antivenom, say scientists.

In animal tests, antibodies found in Tim Friede's blood prevented fatal doses from a wide variety of species. The specific species of venomous snake that a person has been bitten by needs to be matched with the current treatments. However, Mr. Friede's 18-year mission could be a significant step toward developing an all-encompassing antiseptic for snakebite, which kills up to 140,000 people annually and leaves three times as many with permanent disabilities or amputations. Mr. Friede has received more than 700 injections of the venom he prepared from some of the world's deadliest snakes, including multiple species of mambas, cobras, taipans, and kraits, and has been bitten more than 200 times. In the beginning, he wanted to build up his immunity so that he could protect himself when he handled snakes and recorded his adventures on YouTube. But the former truck mechanic said that he had "completely screwed up" early on when two cobra bites in quick succession left him in a coma.

"I wanted to live, not die." I didn't want a finger to go missing. He stated to the BBC, "I didn't want to miss work." "It just became a lifestyle and I just kept pushing and pushing and pushing as hard as I could push - for the people who are 8,000 miles away from me who die from snakebite," Mr. Friede explained. His goal was to develop better treatments for the rest of the world. "I'd love to get some of your blood," she said. Antivenom is currently made by injecting small doses of snake venom into animals, such as horses. Their immune system fights the venom by producing antibodies and these are harvested to be used as a therapy.

But venom and antivenom have to be closely matched because the toxins in a venomous bite vary from one species to another.

Even within the same species, there is a lot of variation; Sri Lankan antivenom against the same species is less effective than Indian antivenom. A team of researchers began searching for a type of immune defence called broadly neutralising antibodies. Instead of targeting the part of a toxin that makes it unique, they target the parts that are common to entire classes of toxin.

That's when Centivax's chief executive officer, Dr. Jacob Glanville, met Tim Friede. He stated, "I reached out" because "immediately I was like, "if anyone in the world has developed these broadly neutralizing antibodies, it's going to be him." I said, "This might be awkward, but I'd love to get my hands on some of your blood" on the first call. Due to the fact that the study would only take blood rather than giving Mr. Friede more venom, the work received ethical approval.One of the two families of venomous snakes, the elapids, were the focus of the study. These snakes include coral snakes, mambas, cobras, taipans, and kraits. Elapids primarily use neurotoxins in their venom, which paralyzes and kills their victims by preventing them from breathing. The World Health Organization has classified 19 elapids as some of the world's most dangerous snakes. They then began looking for defenses in Mr. Friede's blood. Their work, detailed in the journal Cell, identified two broadly neutralising antibodies that could target two classes of neurotoxin. In order to produce their antivenom cocktail, they added a medication that targets a third. In experiments on mice, the cocktail meant the animals survived fatal doses from 13 of the 19 species of venomous snake. They were partially shielded from the remaining six. This is "unparalleled" breadth of protection, according to Dr Glanville, who said it "likely covers a whole bunch of elapids for which there is no current antivenom".The team is working to make the antibodies even better and see if adding a fourth component could make them completely immune to the venom of elapid snakes. Vipers, a different kind of snake, rely more on haemotoxins, which attack the blood, than neurotoxins. In total, snake venom contains approximately a dozen broad categories of toxin, including cytotoxins that directly kill cells. One of the Columbia University researchers, Prof. Peter Kwong, stated, "I think we'll have something effective against each one of those toxin classes in the next 10 or 15 years." Additionally, the investigation continues within Mr. Friede's blood samples. Prof. Kwong stated, "Tim's antibodies are really quite extraordinary - he trained his immune system to get this very, very broad recognition." The ultimate goal is either a single, all-encompassing antivenom or an injection for both elapids and vipers. The reported breadth of protection was "certainly novel" and provided "a strong piece of evidence" that this was a feasible approach, according to Prof. Nick Casewell, head of the centre for snakebite research and interventions at the Liverpool School of Tropical Medicine. "This work unquestionably propels the field in an exciting direction." However, he warned that there was "much work to do" and that extensive testing of the antivenom was still required before it could be used on humans. But Mr. Friede says that getting to this point "makes me feel good." "It was very important to me that I do something good for humanity. I'm happy about it. It is quite cool."