As a critical part of its reproduction process inside the T4 cells, HIV uses an enzyme called protease (PRO-tee-aze). The researchers chose a protein which would be drawn into T4 cells, then attached to it two pieces of a human enzyme called caspase-3 that, when activated, causes the cell to attack itself, basically committing suicide. (A similar process is a standard way that the body controls cancerous or diseased cells.) Entering the infected T4 cell, the compound molecule is sliced by the virus' protease, releasing the bound-up capase-3, which causes the cell's death. The compound also enters non-infected T4 cells, but because they don't contain HIV protease, the capase isn't released to act, so the non-infected cells aren't affected.
Like so many discoveries driven by the AIDS epidemic, the beauty of the technique is that it has potential application to many other diseases, including certain cancers, hepatitis C, and herpes. Their viruses also use forms of protease, so the process ought to work on them as well. Anyone who feels that too much money is spent on AIDS research fails to understand the basic level at which much HIV exploration occurs, with tremendous benefit beyond the boundaries of AIDS.
(For details, see the January issue of Nature Medicine)
-- Sandy Bartlett, Community Information/Education Coordinator
AIDS Services of Austin
ASA Info Line: 458-AIDS