USA: Man lets himself be bitten hundreds of times by poisonous snakes – for research

New York. Sometimes medical progress comes from a surprising direction: A snake enthusiast in the US administered increasingly large doses of snake venom to himself, eventually allowing himself to be bitten by various venomous snakes. In doing so, he made an extraordinary medical development possible.

Building on this, scientists at Columbia University in New York and the medical company Centivax have developed an antidote that they claim is the most widely applicable antidote available to date. The preparation, consisting of three substances, is said to provide at least partial protection against the venom of king cobras, black mambas, and 17 other elapid snakes, as the team reports in the journal Cell .

A major problem in developing antidotes for snakebites is that the venoms often consist of a cocktail of different toxins that have different effects. Antidotes are typically developed by administering the venom of individual snake species to horses or sheep, for example, and isolating the resulting antibodies, the researchers write.

While this procedure could be effective, it could also have serious side effects if the non-human antibodies were used on humans. Furthermore, these so-called antivenoms only work against the venom of the particular snake species. This is different in this case.

American snake enthusiast Tim Friede carries a water cobra in his arms (date of photo unknown). Friede was bitten hundreds of times by a total of 16 different, highly venomous snakes over a period of almost 18 years. Researchers isolated two particularly broad-spectrum antibodies from his blood and developed an antivenom based on them.

Source: Centivax/dpa

"The exciting thing about the donor was his unique immune history," said lead author Jacob Glenville, also CEO of Centivax, in a press release from the publisher Cell Press. Friede was bitten hundreds of times by a total of 16 different, highly venomous snakes over a period of almost 18 years. He survived – and is now employed by Centivax.

The researchers isolated two particularly broad-spectrum antibodies from his blood - LNX-D09 and SNX-B03 - and combined them with an enzyme inhibitor to create an active ingredient that is intended to protect against several venoms from different venomous snakes.

In the study, this cocktail was tested on mice that had previously been administered venom from various venomous snakes. The drug provided complete protection against venom from 13 snake species—including the king cobra, the black mamba, and the inland taipan, considered the world's most venomous snake. The cocktail offered partial protection against six other species—including the green mamba.

The researchers admit that these successes in mice are not yet sufficient. The next step will be to test the antivenom in veterinary clinics on dogs bitten by snakes.

Biochemist Tim Lüddecke from the University of Giessen, who was not involved in the study, sees a further limitation in the fact that the effect is limited to the group of venomous snakes: "The venoms of vipers, which act completely differently and are structured differently, are not addressed." This has important consequences for the application, because this group of snakes (Viperidae) causes the majority of snake bites.

Lüddecke also criticizes the study for focusing solely on the life-saving effect of the antivenom. He also notes that snake venom often causes lifelong physical limitations. Nevertheless, the expert praises the study for combining the most promising approaches in the development of modern active substances against snakebites.

Michael Hust of the Technical University of Braunschweig also emphasizes this. "With the cocktail of these two antibodies and the enzyme inhibitor presented in the study, there is a great opportunity to replace animal sera, which have numerous side effects, with a genetically engineered product."

The team's long-term goal is to develop one or more universal remedies that cover both venomous snakes and vipers. According to the research team, more than 100,000 people die each year from snakebite envenomation, and 300,000 more suffer permanent disabilities, including loss of vision or amputation of limbs.

RND/dpa