To find novel antiviral durgs, investigators have studied proteins that animals produce to protect them from pathogens for a long period of time. Evidence shows that proteins in amphibian secretions have the ability to fight off certian viruses such as HIV and herpes.
Now a newest study reveals that a frog slime protein can kill flu virus. The study, published in Immunity and led by Joshy Jacob from Emory University, reports that a peptide from the skin of the South Indian frog, named "urumin", is virucidal for the H1 variety of influenza viruses.
Unlike humans, frogs do not have an immune system that protects them against pathogens. But the skins of frog are known to secrete host defense peptides, which possess broad antimicrobial function and help protect them. To determine if these peptides could help combat flu, Jacob's collected mucus from the skin of 15 frogs after mild electrical stimulation.
They screened 32 peptides in the mucus and identified four that had anti-flu properties. One peptide, which they named "urumin", in particular grabbed their attention. Urumin effectively destroyed several strains of influenza viruses and some harmful microbes.
With the help of electron microscope, they demonstrated that urumin specifically targeted the stalk of H1 hemagglutinin and physically destroyed influenza virions. The stalk of H1 hemagglutinin is a conserved region of the flu virus, and this region is also the target of antibodies induced by universal flu vaccines. The finding might aid in developing new anti-influenza molecules targeting conserved components on the virus.
Animal experiments demonstrated the protective effect of urumin against lethal flu infection. Importantly, the peptide could kill drug-resistant H1 influenza viruses. Overall, the data suggests that urumin represents a new class of antiviral agent.
Vaccines and antiviral drugs are both important weapons in the fight against harmful viruses. But during pandemics, there may not be enough time to produce vaccines, so antiviral drugs become the first line of defense. It is important to develop new antiviral drugs because of the possible emergence of drug resistance.
In addition to Emory University, Rajiv Gandhi Center for Biotechnology in India, and Icahn School of Medicine at Mount Sinai also participate in the study. (Cusabio offers proteins and antibodies. http://www.cusabio.com/)