American scientists have obtained snake venom-neutralizing antibodies from the blood of a man who injected himself with snake venom for 18 years and used them to create a three-component serum that helps with bites from 13 species of elapid snakes. In the future, they plan to refine the serum to expand its range of action. The work was published in Cell.
Snake venom kills more than 100,000 people every year. Snake bites are treated with a serum obtained from immunized animals. Each serum works against one or more related species of snakes, but it can be difficult to determine which snake bit a person and choose the right drug.
It is also difficult to create a universal antidote: each snake produces from 5 to 70 protein toxins, so even if a neutralizing agent for each of these toxins is found, it is practically impossible to combine them all in one preparation - the total dose of these agents will exceed the permissible safety parameters. In addition, serums obtained from immunizing animals often cause side effects in humans.
In an attempt to solve these problems, scientists from the US National Institutes of Health, led by Peter D. Kwong, became interested in an unusual case of chronic exposure to snake venom: an American injected himself with venom from various snakes and allowed them to bite him for 18 years. In total, the venom entered his body 856 times. The scientists examined his blood and isolated antibodies against the venom of 19 species of elapid snakes, including various species of cobras, mambas, taipans, and kraits. Each type of antibody was injected into mice, and then they were injected with venom from each of the 19 snakes. This allowed the researchers to understand which antibodies neutralized the components of the venom to a greater extent, and then assemble a cocktail from them with a minimum number of components, but in a sufficient amount for neutralization.
The final serum contained two types of antibodies and varespladib, a toxin inhibitor. The first antibody, LNX-D09, neutralized the venom of six snake species, varespladib added protection against the venom of three more species, and the second antibody, SNX-B03, extended the effect of the cocktail to 13 of the 19 snake species. At the same time, the cocktail partially neutralized the venom of the remaining six snake species. The researchers obtained these results after a series of experiments on mice: the animals were first injected with snake venom, and then with a three-component serum.
In the future, the scientists will continue their work and hope to create a universal cocktail against snake bites or make two serums - one against asp bites and the other against viper bites. In addition, they want to conduct research in collaboration with veterinary clinics in Australia, where dogs that have suffered from snake bites are brought.
British researchers have reported an increase in the number of attacks by exotic snakes on residents of the country. The most serious consequences were caused by attacks by vipers (nine severe poisonings) and asps (five severe poisonings and one fatality).