Researchers from the University of Copenhagen have solved an age-old mystery of how the hepatitis C virus evades the human body’s immune defenses using a new method for examining samples of the virus.
A new method for examining virus samples led researchers at the University of Copenhagen and Hvidovre Hospital to answer, which is that the virus puts on a ‘mask’.
By “wearing a mask,” the virus can remain hidden while making copies of itself to infect new cells. The mask disguises the virus in the form of a molecule that is already in our cells.
“How the hepatitis C virus manages to hide in liver cells without being detected by the immune system has always been a bit of a mystery,” says Assistant Professor Jeppe Vinther from the Department of Biology, who led the research with Associate Professor Trolles Scheele and Professor Jens Boch of the Hepatitis C Program in Copenhagen. Our discovery of the virus’s masking strategy is important because it could pave the way for new ways to treat viral infections, and it’s possible that other types of viruses use the same trick.
The mask that the hepatitis virus uses to hide in our cells is called FAD, a molecule made up of vitamin B2 and the energy-carrying molecule ATP.
FAD is vital for our cells to convert energy. The importance of the FAD molecule and the fact that it looks familiar to our cells makes it an ideal camouflage for a virulent virus.
For several years, the research team had had a good idea that FAD helps the virus hide in infected cells, but they lacked a clear way to prove it.
To solve this challenge, they turned to Arabidopsis, an experimental plant well known among researchers.
“We were desperate to find a way to prove our hypothesis, when we purified an enzyme from Arabidopsis that could split the FAD molecule in two,” explains Anna Sherwood from the Department of Biology, who was involved in the study.
Using the enzyme, the researchers were able to split FAD and prove that hepatitis C virus uses it as a mask.
Like both the coronavirus and the influenza virus, hepatitis C is an RNA virus. Its genetic material consists of RNA, which must be copied once the virus has entered the host organism.
New copies of the RNA are used to take over new cells, and one end of the RNA’s genetic material is masked by FAD.
According to Jeppe Vinther, it is very realistic for other RNA viruses to use similar masking techniques to spread undetected by cellular control systems.
In fact, researchers have already found another virus that uses the same strategy. And there will likely be more.
