Some viruses use a form of disguise to avoid being detected by the body’s immune system. Now researchers from Melbourne have found out the secret behind the Trojan-horse like phenomenon. Gabrielle Belz and her colleagues at Parkville’s Walter and Eliza Hall Institute in collaboration with researchers from the University of Cambridge found the key viral gene that was responsible for the phenomenon called K3. The study appeared in the current issue of the Journal of Immunology.
This gene helps viruses such as the herpes virus, and others which cause chronic infection to hide from the immune system. Dr. Belz said, “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.” This gene which is encoded in and made by the virus can disable the machinery used by the body to alert the immune system to infection, allowing the virus to covertly establish disease.
Dendritic cells, which are studied by Dr Belz, Dr Adele Mount and colleagues, act as ‘sentinels’ of the immune system; they are critical for the early detection of invading bacteria and viruses and are one of the first cells to trigger the immune response. “Dendritic cells are called ‘antigen presenting cells’; they digest infectious agents into small fragments and shuttle these fragments to the outside of the cell where they are displayed to virus-specific killer T cells, helping to launch a full-blown immune response,” Dr Belz said.
Dr Belz explained, “In simplistic terms, 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.” The explained the aims of the study was to uncover these hidden viruses adding, “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.”
This research could prompt further development of viral vaccines using this knowledge. Dr Belz said, “. If you understand this, then you know what to target.
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.