Studying sharks’ immune systems could lead to powerful human medicines

Aaron LeBeau regularly visits a local grocery store’s seafood department to stock up on tuna, salmon and octopus. But LeBeau isn’t shopping for himself: He has hungry sharks to feed at his laboratory.

Though they might look mean, “sharks are, to put it lightly, misunderstood,” LeBeau says. He’s a professor of pathology at the University of Wisconsin-Madison. Nurse sharks – the kind he studies – are “probably the most docile sharks in nature. Pretty much all they do is sleep and eat.”

And they might hold the key to better treatments for COVID-19, cancer and other diseases.

Before the coronavirus pandemic, LeBeau was researching the antibodies of llamas and alpacas, which have shown potential to treat various illnesses. He studies antibody-based therapies for cancer. An antibody is a protein immune systems make in response to a foreign substance.

A Scottish biotechnology company called Elasmogen was conducting similar research, but with sharks instead of llamas. LeBeau and Elasmogen decided to work together on shark antibodies for cancer research. As the coronavirus spread, the team changed course and began exploring whether the antibodies might work against the virus.

Sharks’ strong immune systems have helped them survive for more than 400 million years. “What they’re doing, evolutionarily, it’s been working for a long time,” LeBeau says.

At his lab, the four resident nurse sharks swim in a tank looking for food to suction up. They eat every other day. Occasionally, the menu includes something special, such as lobster for Thanksgiving. Blood is drawn from the sharks each month to look for antibodies. To keep them comfortable during the procedure, they’re placed in a smaller tank with anesthesia mixed into the water.

Compared to human antibodies, shark antibodies are much better at neutralizing invading viruses. Shark antibodies are very small and very flexible, LeBeau says. “So, they fit into areas of proteins that human antibodies can’t get to.”

Shark antibodies are also tough, he says. “They’re virtually indestructible.” That’s because they have to survive in shark blood, which is high in salt, something that normally makes antibodies fall apart.

The research team found that shark antibodies worked against several coronaviruses, according to a December study in Nature Communications. In the lab, the antibodies also neutralized the omicron variant of the coronavirus, LeBeau says. Because one of the antibodies being studied binds to a part of the virus that never changes, researchers think the treatment will work against future variants, too.

Antibody therapy can be critical for people with weakened immune systems who may not get protection from vaccinations. “It’s possible that 10 years from now, the first line of therapy for a COVID-19 infection will be a shark antibody,” LeBeau says.

Shark antibodies don’t need to be kept cold, so medicines made with them could be shipped around the world more easily than those that do. “If you develop a shark antibody therapy for dengue fever, it could easily be used in the tropics,” he says.

LeBeau sees the sharks in his lab as much more than research subjects. “The coolest thing about them is you would never think that they have personalities,” he says. “Each shark is very, very different.”

Once the sharks in his lab grow too large for their tank, they’ll be relocated to an aquarium, LeBeau says. “Our sharks will live nice, long, happy lives.”