New development in flu prevention & treatment

By Dr. Ananya Mandal, MDJul 20 2010

In a groundbreaking development, scientists at the Australian National University in Canberra have found the key to the mutation of the flu virus. This may allow the manufacturing of a life-long vaccine stopping the need for repeated vaccinations. The scientists reveal that they have found a protein in the virus that changes or mutates in order to develop resistance in the virus.

According to ANU's Marco Casarotto, the vaccines that are currently used may become ineffective in the next five years due to these rapid mutations. “What is important is for all research groups around the world to work on different aspects of the flu, this sort of multi-pronged attack is really necessary,” he said. “We know exactly what target we have to aim for, and we also know the mutations that are out there as well, and we have got a good idea now of how to overcome these mutations,” he explained.

The drugs used in influenza include neuraminidase inhibitors - oseltamivir and zanamivir that prevent the spread of the virus. There were drugs used in the 1960’s called adamantanes. They are no longer used because the virus had developed a resistance to them. These adamantanes target and inhibit a proton-selective ion channel, M2 in the influenza virus but the exact biding site of the drug was elusive till now. Scientists at the Australian National University now have found that adamantanes bound to two sites on M2, and found that only one of these was the primary site for its pharmacological action. They also found that M2 could still be a viable target option making adamantanes useful again.

Dr Marco Casarotto and PhD student, Mr Matthew Rosenberg, of the John Curtin School of Medical Research at ANU studied two adamantanes - amantadine and rimantadine in a series of surface plasmonresonance (SPR) experiments to check their affinity to M2 ion channels. They found the two binding sites on the virus.

According to Dr Casarotto, “Tamiflu and Relenza are the main drugs out there, but we can’t get too relaxed - resistance to Tamiflu is already evident… In a few years, those drugs may be ineffective, and we’ll be left with nothing frontline to fight an outbreak. This research paves the way for the next generation of drugs.”

The paper on their findings entitled, “Coexistence of two adamantane binding sites in the influenza A M2 ion channel”, is published in the latest issue of Proceedings of the National Academy of Sciences (PNAS).