Viruses have well-known strategies for slipping past the immune system. These include faking or stealing a molecular identification badge that prevents a cell from recognizing a virus.
Scientists at Washington University School of Medicine in St. Louis and elsewhere have found some viruses have another trick. They can block the immune system protein that checks for the identification badge.
The blocking structure is called a stem-loop, found at the beginning of the virus's genetic material.
This is the first time scientists have found an immune-fighting mechanism built directly into the genetic material of a virus.
They are looking for ways to disable it and searching for similar mechanisms that may be built into the genetic material of other disease-causing microorganisms.
"When the stem-loop is in place and stable, it blocks a host cell immune protein that otherwise would bind to the virus and stop the infectious process," senior author Michael Diamond, MD, PhD, professor of medicine, said.
"We found that changing a single letter of the virus's genetic code can disable the stem-loop's protective effects and allow the virus to be recognized by the host immune protein. We hope to find ways to weaken the stem-loop structure with drugs or other treatments, restoring the natural virus-fighting capabilities of the cell and stopping or slowing some viral infections," he added.