Nanobodies are very small antibody-like structures unique to the camelid immune system (llamas, alpacas and their relatives). While ordinary mammalian antibodies are relatively large molecules, camelid antibodies sport much smaller structures—nanobodies—that possess all the chemical-targeting ability of a full-blown antibody. Scientists have worked out how to cut these nanobodies off and mass-produce them as individual neutralising units.
Nanobodies are very stable and, unlike ordinary antibodies, readily survive freeze-drying—useful for medicines needed in places where electricity supplies are unreliable and refrigeration a challenge. Their small size means they can penetrate deep into dense tissues, more readily cross the blood-brain barrier, and reach parts of the body that bigger antibodies struggle to access reliably.
In a paper published in Nature in October 2025, a group led by Andreas Laustsen at the Technical University of Denmark used nanobodies to create a broad-spectrum antivenom effective against the bites of many different snakes. The team injected an alpaca and a llama with the venoms of 18 deadly African snakes (including the black mamba, cape cobra and Nubian spitting cobra), giving low initial doses followed by fortnightly boosters over 60 weeks.
The researchers screened the resulting nanobodies and created a shortlist of eight which were effective against almost all the toxins produced by the snakes. Combined into a single antivenom and tested on mice, the cocktail allowed survival from otherwise lethal doses of venom from 17 of the 18 snakes (only the eastern green mamba remained deadly). The antivenom also almost always prevented tissue death at the injection site—something current antivenoms struggle to stop.
Traditional antivenoms are produced by milking snakes and injecting their venom into large animals such as horses, then collecting the resulting antibodies. They are species-specific and require the victim to know which snake delivered the bite. Of the more than 300,000 people bitten by snakes each year in sub-Saharan Africa, over 7,000 die and a further 10,000 need the bitten limb amputated.
Dr Laustsen's team is now collecting viper venom to attempt a similar broad-spectrum antivenom for that family, which includes the eastern diamondback rattlesnake and the fer-de-lance. It may be possible to combine antivenoms against both elapids and vipers into a single medicine.
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