New T cell discovery shows promise for herpes vaccine

Fred Hutchinson Cancer Research Center and University of Washington scientists announced on Wednesday that they discovered the cells responsible for suppressing herpes symptoms, which may provide a viable vaccine.

The new cells discovered, called CD8αα+ T cells, are promising components in developing a vaccine against herpes simplex virus type 2. If scientists can find the new T cells’ specific molecular targets, called epitopes, the development of a viable vaccine will be underway.

The findings of the study were posted in the advance online edition of Nature on Wednesday. Larry Corey, president of Fred Hutch, wrote about the discovery and its importance.

"The discovery of this special class of cells that sit right at the nerve endings where HSV-2 is released into skin is changing how we think about HSV-2 and possible vaccines," Corey said. "For the first time, we know the type of immune cells that the body uses to prevent outbreaks. We also know these cells are quite effective in containing most reactivations of HSV-2. If we can boost the effectiveness of these immune cells we are likely to be able to contain this infection at the point of attack and stop the virus from spreading in the first place. We're excited about our discoveries because these cells might also prevent other types of viral infections, including HIV infection."

During the research study, in which scientists used a unique sequential human biopsy research method to study the cells in their natural state, scientists found the CD8αα+ T cells persisted on the skin, not just in the blood as previously thought. This is why scientists believe this T cell is responsible for infected persons with herpes not having any symptoms for some time, making most infected persons unaware of infection.

"The cells we found perform immune surveillance and contain the virus in the key battlefield where infection occurs, which is the dermal-epidermal junction," Jia Zhu,corresponding author and research assistant in the study, said. "These cells are persistent in the skin and represent a newly discovered phenotype distinguished from those of CD8+ T cells circulating in the blood."

If an effective vaccine can be developed, it can help some 776,000 infected persons in the U.S. alone. There is currently no effective vaccine against the infection, which not only affects the adult but also newborns during birth.

"While antiviral treatment is available, the virus often breaks through this barrier and patients still can transmit the infection to others," Corey said. "In addition, newborn herpes is one of the leading infections transmitted from mothers to children at the time of delivery. An effective genital herpes vaccine is needed to eliminate this complication of HSV-2 infection."