Flu fighter found in frog slime

In time, this could become the basis of new vaccines

Slime produced by this newly identified species of frog contains a protein that appears promising for fighting flu.

SANIL GEORGE & JESSICA SHARTOUNY

Ewwww. Frog slime just could be the source of the next flu drug. It’s really not a crazy idea, though. Scientists have spent decades searching for new drugs to combat viruses by mining proteins that animals make to fight off germs. And lately, proteins found in amphibian mucus have shown promise against HIV and herpes. Now it’s influenza.

David Holthausen is a graduate student in immunology at Emory University in Atlanta, Ga. He and his colleagues sampled slime from the skin of a frog. Called Hydrophylax bahuvistara, this frog species was discovered in southern India. Its mucus contains a host of proteins. The researchers tested 32 of them against a flu virus. Four showed promise. All but one, however, proved toxic to mammals. So the scientists focused on the last. They’re calling it urumin for a type of sword used in the region of India where this frog was found.

Urumin didn’t harm mammals. It did, however, seem to give several flu viruses a hard time.

Influenza viruses mutate frequently, forming new types, known as strains. The family of each strain is known by a series of letters and numbers. Holthausen and his group chose common disease-causing strains. Four belonged to the H3N2 family and eight to the H1N1 family. Urumin slowed somewhat the ability of H3N2 viruses to reproduce. It was particularly good, however, at killing H1N1 viruses. And that’s fortunate, because these are a more common family of strains that sicken people.

Mice treated with the frog-slime protein, also had a better chance of survival when exposed to a killer strain of flu. The slime protein even cut the reproduction of viruses in seven strains that had all become resistant to the effects of anti-viral drugs.

The new research shows that urumin works by blowing up flu virus particles. It targets a so-called stalk region of a protein in the H1 strains.

It will take more work to turn urumin into a true drug. But in time, it could serve as the basis for a new family of flu vaccines. Holthausen’s group described its new findings April 18 in Immunity.

Helen Thompson is the associate digital editor. She has undergraduate degrees in biology and English from Trinity University and a master’s degree in science writing from Johns Hopkins University.

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