Study says protein helps virus conceal itself from body's defenses
TUESDAY, April 1 (HealthDay News) -- U.S. researchers say they've discovered how HIV -- the virus that causes AIDS -- hides in human cells to avoid being destroyed by the body's immune cells.
They explained that when a normal virus, such as the common cold, infects a person, the immune system responds and produces cells that quickly eliminate the virus. However, HIV makes itself appear as part of the normal trash in a cell, rather than being clearly visible on the cell surface.
"HIV can make a protein called Nef, which helps the virus hide," researcher Dr. Kathleen Collins, an associate professor at the University of Michigan, said in a prepared statement.
"Nef interferes with one important part of our defenses, which helps our immune system recognize infected cells, by displaying pieces of the infecting virus or bacteria on the cell surface, forming a target for our bodies' killer cells. When HIV infects one of our cells, the protein Nef binds to this helper system and alters it in such a way that the cell believes it belongs in the cellular trash bin rather than on the surface where our main defenses can see it," she said.
Collins added that the Nef protein recruits other proteins naturally made by cells to help HIV hide from immune cells. She and her colleagues identified these natural proteins and developed inhibitors that block their actions and reverse the activity of Nef. This may help the immune system to detect and destroy HIV.
"We are currently screening a whole range of substances, looking for small molecule inhibitors which could be developed into drugs to provide better therapies for people with HIV and AIDS," Collins said.
"We have discovered that Nef takes on notably different shapes and structural forms in different contexts, which allows it to reveal or obscure different traffic signals within the infected cell as needed. Once we have a better understanding of the surfaces and shapes involved in these interactions, we will be in a better position to develop medicines which may someday help to combat AIDS."
The research was to be presented April 1 at the Society for General Microbiology annual meeting, in Edinburgh, Scotland.
The U.S. Centers for Disease Control and Prevention has more about HIV/AIDS.
-- Robert Preidt
SOURCE: Society for General Microbiology, news release, March 31, 2008
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