3-D HIV
IT MAY NOT LOOK LIKE much, but don't be fooled. In what has been termed the biggest breakthrough in HIV since the discovery of the virus 15 years ago, researchers at Columbia University and the Dana-Farber Institute in Boston recently published the first 3-D X-ray crystallography snapshots of HIV infecting a cell. What they saw astonished them, revealing exactly how HIV escapes detection by the immune system. Think of a one-two boxing move: First, HIV uses a protein on its surface called a gp120 "probe" to clamp onto an antenna-like protein on the T-cell surface, called a CD4 receptor. Using a "sugar cloak," the virus then hides behind hidden structures and escapes being identified and killed by cells. Next the gp120 probe clamps onto another T-cell protein receptor called a chemokine. At that point, through some mysterious mechanism, the T-cell opens holes in its membrane that allow HIV to insert its genetic material. The result: a knockout infection.
Now for round two. Armed with a blueprint, scientists are fast at work designing compounds to block the binding sites on HIV. "It's the difference between being blind and being sighted," said Dr. Joseph Sodroski, one author of the report.
PHOTO COURTESY OF NATURE MAGAZINE
