By Bridie Smith
MELBOURNE researchers have discovered the secret behind a disguise some viruses use to evade detection by the body's immune system.
Gabrielle Belz and her colleagues at Parkville's Walter and Eliza Hall Institute worked with researchers from the University of Cambridge to establish the modus operandi of key viral gene K3.
Trojan horse-like, the gene helps viruses such as the herpes virus, and others which cause chronic infection, to slip under the radar of the body's immune system in a game of deception.
''We knew that these genes work once the virus is actually in the body and substantially established - but our question was [whether they are] really helping the virus get past the immune system's defences right at the front line,'' Dr Belz said.
In the current Journal of Immunology, the researchers showed that the gene - which is encoded in and made by the virus - disables the machinery used by the body to alert the immune system to infection, allowing the virus to covertly establish disease.
Chronic infections are one of the greatest health challenges for the Western world, and currently there are very few ways of dealing with them.
''In simplistic terms,'' Dr Belz said, ''acute infections are relatively self-limiting as once they go through their cycle they move on to the next person … but it's not the case with chronic infections. Plus, if you can't see the virus then you don't know what the enemy looks like.''
She said the goal was to unmask the virus so the immune system could attack it, preventing disease from becoming established.
''Understanding how these sorts of genes work at a molecular and cellular point of view is important because if we know that, then perhaps we can uncover these inhibitors that allow that gene not to work, so the virus will be seen.''
The findings, which have given scientists an insight into how early the body's protection mechanisms are tricked, could prompt researchers to re-evaluate how viral vaccines are developed.
Dr Belz said it was the body's dendritic cells, effectively immune system sentinels, which were not picking up the virus in disguise. ''If you understand this, then you know what to target,'' she said.
The research was supported by the National Health and Medical Research Council, the Wellcome Trust, the Swiss National Science Foundation, the Viertel Foundation and the Howard Hughes Medical Institute.