Frog mucus may offer protection against flu virus

Fairy tales about kissing frogs may have been onto something after all, maybe not to acquire a prince but possibly to gain resistance against certain strains of flu virus. Researchers from Emory University in Atlanta, in collaboration with researchers from the Rajiv Gandhi Center for Biotechnology in India, discovered that the mucus produced by a certain frog was able to destroy the influenza virus.

In particular, the frog is Hydrophylax bahuvistara, native to Southern India, and has found to be able to kill the H1 variety of the influenza virus. Researchers were able to identify a particular peptide, which is named urumin (named after the South Indian flexible sword), that was able to provide protection to the frog against influenza.

Some of the antiviral peptides in the frog were found to be toxic to human cells, as they broke the structure of cell membranes. However, in the case of urumin, the peptide was found to only disrupt the flu virus whilst leaving human cells undisturbed.

Urumin binds to hemagglutinin, an area of the flu virus that does not differ much between strains and is therefore is an important target in flu vaccines and treatments.

Joshy Jacob, Associate Professor of Microbiology and Immunology at Emory Vaccine Center and Emory University School of Medicine, said on the discovery: "I was almost knocked off my chair…In the beginning, I thought that when you do drug discovery, you have to go through thousands of drug candidates, even a million, before you get 1 or 2 hits. And here we did 32 peptides, and we had 4 hits."

Of the four hits, only one, urumin, was non-toxic to human cells. In mouse studies, the peptide was able to protect unvaccinated mice against lethal doses of certain flu viruses, including the H1 strains of flu that rose to pandemic levels in 2009.

The next stage for research will be to work out a safe and effective method of delivery to humans and to test for further peptides that may be useful in other areas of medicine.