Shark Antibodies Could Create New Methods to Fight Serious Illness

There's a lot we can learn from sharks and now, scientists are using them to find out how we can combat serious illnesses. Researchers have taken a look at the antibodies in sharks to better understand how to stabilize them for use to combat sickness.

While custom-tailored antibodies could be good weapons against severe illness, it's difficult to stabilize them. In fact, their stability is a decisive factor in every step from production and storage to therapeutic application. That's why scientists turned to shark antibodies.

From an evolutionary perspective, sharks are some of the oldest animals with a "modern" immune system. They've been in existence for over 500 million years, and have changed very little as far as evolution goes. What's more interesting, though, is the fact that shark blood contains large quantities of urea which allows it to survive in salt water. This urea can destabilize sensitive protein molecules such as antibodies, which make shark antibodies good structures to study when it comes to stabilization.

"Human antibodies would collapse under these conditions," said Matthias Feige, one of the researchers, in a news release. "Shark antibodies must, therefore, possess structural characteristics that make them particularly robust."

The researchers examined the shark antibody IgNAR (immunoglobulin new antigen receptor). The crystallized parts of the antibody and then determined their atomic structures by using X-ray crystallography, comparing the segments with previously known structures of other immunoglobulins.

In the end, the researchers found that the Ig folding typical for antibodies had already developed over 500 million years ago, since it's also present in sharks. Not only that, but they identified the source of a shark's antibody stability. It turns out that the stability is due to an additional salt bridge between structurally important amino acid chains and a large non-polar nucleus of the Ig fold.

The findings reveal a little bit more about how shark antibodies are so stable. This, in turn, could pave the way for future research when it comes to creating therapeutic antibodies to treat illness. Scientists could potentially integrate the stabilizing principles into human antibodies.

The findings are published in the journal Proceedings of the National Academy of Sciences.