APR 20, 2017 2:19 PM PDT

Flu-Busting Peptide Found in Frog Slime


Even though this year’s peak flu season can be considered to have passed, people can contract the virus well into May. And while flu vaccines remain the number one recommended defense, scientists say they have stumbled on a compound in frog mucus that may also confer immunity to the influenza virus.

Not unlike humans, frogs excrete mucus or slime as a way to protect itself from pathogens. In the case of frogs, their mucus is produced throughout their skin, making them quite slimy creatures to behold. But for decades, scientists have been interested in the frog’s slimy secretion, as they contain “host defense peptides” that could unlock protection for pathogens that infect humans.

Indeed, scientists at the Emory University found that the slime of a particular frog, the Indian Hydrophylax bahuvistara, has the potential to kill the flu virus.

"Different frogs make different peptides, depending on where their habitat is. You and I make host defense peptides ourselves," said Joshy Jacob, flu specialist, and the study’s senior investigator. "It's a natural innate immune mediator that all living organisms maintain. We just happened to find one that the frog makes that just happens to be effective against the H1 influenza type."

In particular, the team identified four peptides – short amino acid chains – that had flu-killing capacity. "I was almost knocked off my chair," said Jacob. "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."

The most promising peptide of the four is urumin. This was the only molecule that seemed to kill the flu virus without harming human cells. The other three molecules could kill the flu virus, but also harmed human red blood cells in the process. In mice, urumin exposure saved mice from a lethal dose of some flu strains, demonstrating the compound’s capacity to fend off the viral infection.

But don’t think that rubbing frog slime on yourself will offer any protection against the flu. The team has yet to fully investigate just how urumin in the Indian frog slime kills the virus. Moreover, urumin was effective against H1 strains of the flu, but not against current strains like the H3N2. And finally, the purified peptide has yet to go through the rigors of clinical trials to establish its effects in humans.

So, until we understand more about how urumin works, the flu vaccine will still be the best bet we have against the aches and pains brought on by the flu. Of note, the flu shot works by exposing the body’s immune system to a dead version of the flu virus. This exposure is enough to rally our immune cells against the live strains circulating during flu season. Getting a well-matched flu shot at the right time could reduce the risk of the flu by as much as 60 percent, the CDC said. This is particularly important for very young and very old individuals, and individuals with immunocompromised systems, as it’s more challenging for them to recover from the flu.

Additional source: Emory Health Sciences

About the Author
Doctorate (PhD)
I am a human geneticist, passionate about telling stories to make science more engaging and approachable. Find more of my writing at the Hopkins BioMedical Odyssey blog and at TheGeneTwist.com.
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