(NEXSTAR) – Since the start of the pandemic, various animals have made headlines when testing positive for COVID-19: mink on farms, deer in the wild, big cats at zoos. Now, another animal is now receiving attention — and not because of a positive test, but because of the positive impact it could have on the fight against coronaviruses.
Researchers are looking to sharks and their antibody-like proteins to neutralize the current COVID virus and prepare for viruses that could come in the future.
Coronaviruses, which refer to specific types of viruses, have existed long before COVID-19 was detected. As the John Hopkins School of Medicine explains, coronaviruses are named based on their appearance — “corona” means “crown,” and the term is used to describe the virus’s outer layers, which are covered with spike proteins. In 2019, a coronavirus, SARS-CoV-2, was found. It causes a respiratory illness, which is now known as COVID-19.
VNARs (variable new antigen receptors), which are unique antibody-like proteins derived from the immune systems of sharks, can prevent the virus that causes COVID-19, its variants, and related coronavirus from infecting human cells, a study from the University of Wisconsin-Madison has found.
In the study — a collaboration between UW-Madison, the University of Minnesota, and Elasmogen, a Scotland biomedical company that develops therapeutic VNARs — shark VNARs were tested against SARS-CoV-2 and a version of the virus that cannot replicate in cells. Three VNARs from a “pool of billions” were found to be effective in stopping the virus from infecting human cells.
The three VNARs were also determined to be effective against SARS-CoV-1, which caused the 2003 outbreak of SARS. Shark VNARs were also able to neutralize WIV1-CoV, a variant currently found only in bats.
According to the study, published in Nature Communications, one of the VNAR, 3B4, attached to a groove on the spike protein and blocked it from binding to the human cell. Researchers say this same groove is similar to other coronaviruses, including MERS. Where it binds does not change when it comes to variants, either, the study explains.
Another VNAR, 2CO2, appeared to lock the spike protein in an inactive form, researchers report. Where this VNAR binds, though, is altered in some of SARS-CoV-2’s variants. Researchers say they “do not have any structural data for the binding location” for the third VNAR, 4C10, but virus “mutations do not have a substantial effect” on its effectiveness.
Researchers say multiple shark VNARs could be included in a cocktail for future therapies. This is cheaper and easier to manufacture than human antibodies, but has not yet been tested in humans.
“The big issue is there are a number of coronaviruses that are poised for emergence in humans,” said Aaron LeBeau, a UW–Madison professor of pathology who helped lead the study, in a news release. “What we’re doing is preparing an arsenal of shark VNAR therapeutics that could be used down the road for future SARS outbreaks. It’s a kind of insurance against the future.”