Discovery May One Day Lead to Herpes Vaccine
Understanding specialized cells could be key to preventing genital herpes, researchers say
By Brenda Goodman
WEDNESDAY, May 8 (HealthDay News) -- A specialized kind of immune cell that patrols the skin of people infected with the herpes virus appears to prevent the outbreak of painful sores, a new study suggests.
Researchers think the cells may be key to developing a potential vaccine against genital herpes, which afflicts more than 24 million people in the United States, according to the U.S. Centers for Disease Control and Prevention.
For the study, published online May 8 in the journal Nature, researchers took skin samples from people infected with HSV-2, the virus that causes genital herpes, and followed them as they healed from recent outbreaks.
Working with a high-powered microscope, researchers used fluorescent stains to find and label different types of immune cells in the skin. They were most interested in cells called CD8 killer T-cells.
Unlike antibodies, which bind to bacteria and viruses, preventing them from infecting cells in the first place, CD8 cells are a second line of defense, said Bryan Cullen, director of the Center for Virology at Duke University, in Durham, N.C.
"They kill virus-infected cells as quickly as possible after they become infected," said Cullen, who also studies herpes infections but was not involved in the research. Killing infected cells prevents them from becoming factories that crank out more copies of the virus, he said.
Scientists once thought that all CD8 cells roamed the body, looking for infected cells through the bloodstream.
By watching the immune response as it unfolded in the skin, researchers realized that there were special CD8 cells that stayed in place, patrolling the area around nerve endings like beat cops. They guessed that the cells were waiting for the herpes virus to emerge and cause trouble.
To test that theory, they used very fine lasers to pluck out these specialized cells to see what kinds of proteins they were making.
In skin that had some shedding of the herpes virus, the specialized CD8 cells made a lot of perforin, a protein that penetrates membranes to kill cells. In skin with no active virus, the specialized CD8 cells didn't make any perforin, suggesting that the function of the cells is indeed to kill herpes-infected cells.