Key gene helps virus sabotage immune system

SYDNEY - A key gene helps viruses sabotage the immune system by making them ‘invisible’ and spreading infections.

Immunologists from the Walter and Eliza Hall Institute in Australia with the University of Cambridge in Britain have been studying how and why the immune system is unable to eliminate these infections.

Gabrielle Belz, Adele Mount and colleagues are particularly interested in immune system cells called dendritic cells and their interaction with viruses that cause chronic infections, the Journal of Immunology reports.

“We are trying to understand how chronic infections sneak past the usually highly effective immune armoury and covertly establish disease,” Belz said.

“If we can stop these infections from establishing, then we can eliminate, or substantially reduce, that societal burden,” according to a Walter and Eliza Hall statement.

Dendritic cells act as ’sentinels’ of the immune system, they are critical for the early detection of invading bugs 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.”

Their results show that a viral gene called K3 rapidly disables the antigen-processing machinery normally used by dendritic cells to alert the immune system to infections.

“This gene quickly helps the virus to hide from the immune system by subverting normal antigen presentation to T cells, which have the critical task of destroying virally-infected cells,” Belz addded.