The incredible antibodies of sharks, llamas and camels
Sharks and llamas share a strange quirk of their immune systems. Hayley Bennett finds out how their ‘nanobodies’ could help us tackle Covid and a host of other diseases
Camelids like camels and llamas have ‘normal’ antibodies like ours as well as these light-chain-less antibodies or ‘nanobodies’, which lack their arm plates but also have shorter arms, making them much more compact – around 75kDa compared to 150kDa. What was intriguing about this discovery was that the camelids appeared to have tinkered with a system that had worked well enough for millions of years. In other animals, it’s the paired heavy–light chain structure that allows us to bind billions of different targets on invading microbes.
What’s fascinating is that this system hasn’t just cropped up once in evolutionary history, but at least twice. Sharks use single-chain antibodies called immunoglobulin new antigen receptors that are even smaller – and more stable – than camelid antibodies.
Sanofi has been developing nanobodies that it links to make multi-pronged therapeutics since 2018.