National Institute of Allergy and Infectious Diseases (NIAID) virologist Dr Jeffrey Cohen, and NIAID research fellow Dr Qingxue Li, discovered that a surface protein of varicella-zoster virus attaches to a cellular protein called insulin-degrading enzyme, using it as a receptor to enter and infect cells. In the October 20, 2006 issue of the journal Cell, they also describe how interfering with this interaction inhibits the spread of virus among cells in the test tube. The scientists contend that the discovery of this receptor is important in understanding varicella-zoster virus.
Their finding is also an important first step towards designing new therapies for shingles. “If safe and effective ways of disrupting this interaction can be found, eventually new interventions may be developed for treating people with this painful and debilitating disease,” commented NIAID Director Dr Anthony S. Fauci.
Shingles occurs only in people who have already had chickenpox. Once chickenpox has run its course, some virus remains dormant in nerve cells at the base of the brain and alongside the spinal cord. With advancing age and diminished immunity, the virus can reactivate years later and travel down the nerve cells to the skin.
Shingles drugs already exist that prevent viral replication, speed healing and reduce the severity of the disease. But some people who are immunocompromised develop a disseminated infection and resistance to these drugs. “An additional drug against a completely different type of target might be useful for these people,” says Dr Cohen.
Just this year, the FDA licensed a shingles vaccine for people 60 and older after a large clinical trial carried out in collaboration with NIAID showed that the vaccine could reduce the expected number of shingles cases by half in this age group. Yet, says Dr Li, some people who are the most vulnerable to shingles – people with AIDS and others who are severely immunocompromised – cannot receive the vaccine because it is made from a live virus.