A test vaccine against genital herpes shows full protection against the live virus in mice, researchers report March 10 in eLIFE.
Previous herpes vaccine candidates contained a viral protein called gD-2, an obvious component since it is needed for herpes to invade cells and would therefore elicit an immune reaction. Such experimental vaccines succeeded in guinea pigs, but they failed in people. Researchers at Albert Einstein College of Medicine in New York City wondered if having a gD-2 component in a vaccine might “mask” other viral particles and allow them to escape immune detection.
“A dominant protein like that is like a loud person in a room,” says study coauthor Betsy Herold, a pediatric infectious disease doctor. “Other people speaking can’t be heard.” Similarly, the human immune system might have been responding to gD-2 but not the full array of herpes particles, she hypothesizes. So Herold and her colleagues devised a way to usher a vaccine without the “loud” protein into cells. When injected with this weakened form of the virus, mice ginned up protection against herpes and were able to fend off the virus.
Rather than boost production of antibodies that neutralize gD-2, the experimental vaccine awakens an antibody that binds to an immune protein called the FC-gamma receptor. Together, they latch onto virally infected cells and recruit an array of immune cells that kill the cell and halt infection. Further tests are planned. Genital herpes affects more than 500 million people worldwide, the World Health Organization has estimated.