New infections could trigger cancer-causing herpes viruses that have been lying dormant in the body for years to reemerge.
Researchers discovered that interactions with other infections later in life can trigger dormant viruses, resulting in further illness, a University of Florida news release reported. Understanding more about this process could help researchers develop better methods to prevent these diseases.
"Probably 95 percent of us have been infected with at least one herpes virus, but many people never have a problem with it," study co-author Rolf Renne, Ph.D., a professor of molecular genetics and microbiology in the UF College of Medicine and a member of the UF Genetics Institute and the UF Health Cancer Center, said in the news release. "The question has been: What happens to reactivate these viruses to cause disease?"
The researchers found that parasitic infections later in life can spark an immune reaction that allows the herpes virus to reactivate. The team focused on human herpes virus 8, which is a herpes virus linked to a form of cancer called Kaposi sarcoma.
The team found that after the initial herpes infection is kept at bay by a protein called interferon gamma, this explains why the virus usually lies dormant. If the immune system later had to respond to an infection from a parasitic worm called a helminth the protein interleukin 4 is released; this blocks the interferon gamma from doing its job, allowing the virus to sneak by. When this virus replicates it infects new cells, increasing the risk of cancer.
"The fact that the virus can 'sense' the immune reaction to a worm and respond by reactivating is a remarkable example of co-evolution," senior author Herbert W. Virgin IV, M.D., Ph.D., of Washington University in St. Louis, said in the news release. "We think other interactions between multiple infectious agents and the immune system will be discovered over time that we will view as similarly sophisticated or maybe even devious. Understanding these interactions will help us survive in a complex microbial world."
