Scientists decode how dengue virus evades immunity

Scientists have discovered a new pathway the dengue virus takes to suppress the human immune system, expressing hope for the development for more effective drugs to tackle the deadly disease.

When a virus enters the body and infects cells, it induces the production and release of interferons (IFNs), which are proteins that raise the bodies' anti-viral defence mechanisms.

The dengue virus enters the cell and produces large quantities of a non-coding, highly-structured viral RNA termed "sfRNA" - part of the genetic material of the dengue virus.

The team found that "sfRNA" attaches itself to proteins in the cell that typically help in producing antiviral proteins in response to interferons (IFNs).

Because of this interaction, the cell is unable to mount its antiviral defences and protect itself against virus replication.

"We have not only found a new way in which the dengue virus interferes with the human immune system, we have also uncovered the first mechanistic insight into how this non-coding RNA works," said professor Mariano Garcia-Blanco from Duke-NUS Graduate Medical School Singapore (Duke-NUS).

The dengue virus employs multiple strategies to evade our immune responses.

For years, the conventional approach to target the dengue virus was through vector control.

This is because the mechanics of the virus have been elusive, which, in turn, hampered the development of effective treatments and vaccines.

"The new findings were surprising because in 30 years of RNA and dengue-related research, this new mechanism was never discovered," Garcia-Blanco added.

It provides a novel way in which dengue virus is able to avoid being killed by our antiviral response, said the researchers in a paper published in the journal PLOS Pathogens.