Kiss the wrong person and you might get mononucleosis, which could mean days laid up in bed with swollen glands and fatigue. For monkeys, however, the Epstein-Barr virus (EBV) responsible for mono is often the kiss of death, which has been a big hurdle to studying the bug in primate models. Now, scientists have found that primates infected with a genetically similar virus come down with monolike symptoms. The findings, reported in today's issue of Science,* offer a promising new avenue for testing drugs against EBV, which has also been implicated in sinus and throat cancer.
Injecting EBV itself into monkeys either triggers tumors in white blood cells that kill the animals or leaves them uninfected with the virus. Taking a cue from AIDS researchers, who use simian immunodeficiency virus in monkeys as a model for HIV infection, Fred Wang of Brigham and Women's Hospital and Harvard Medical School in Boston set out to find a primate version of EBV. "The best way to study a human virus is to find a natural analog in animals," Wang says.
Wang homed in on a rhesus lymphocryptovirus (LCV), which had earlier been found to express coat proteins similar to those of EBV. Several days after receiving an oral dose of LCV, two rhesus monkeys came down with swollen lymph glands and elevated levels of a type of white blood cell, CD23+ B lymphocytes—a classic sign of early stages of EBV infection in people.
Despite its small size, "the study shows just how analogous the LCV infection in monkeys is to EBV infection in humans," says Nancy Raab-Traub, a molecular biologist at the University of North Carolina, Chapel Hill. "This is an incredibly important model," she says, that can be used for everything from testing drugs to probing EBV's potential role in sinus cancer.