October 7, 2001

Scientists Find Protein That Helps HIV Spread

By Amy Norton


NEW YORK (Reuters Health) - Scientists have identified a protein in normal body cells that appears to help HIV spread throughout the body. They speculate that drugs designed to block this protein could leave HIV stranded in certain cells, unable to spread and progress to AIDS.

However, it is still unclear how well the protein--called Tsg101--could be inhibited in humans, according to the study's leader, Wesley I. Sunquist of the University of Utah in Salt Lake City.

``This is basic research,'' he said in an interview with Reuters Health, ``and it could be a long time until we see this used in therapy.''

Still, Sunquist added, Tsg101 ``looks like a promising target'' for new HIV drugs.

He and his colleagues reached that conclusion after studying how HIV moves from cell to cell to establish an infection. They found that after HIV infects a healthy cell, it usurps that cell's Tsg101, using it to help viral particles ''bud'' on the cell's surface. This budding is necessary for HIV to spread to other cells.

But when Sunquist's team depleted Tsg101 within cells, they were able to stop HIV budding on cell surfaces, according to their report in the October 5th issue of the journal Cell.

All of this implies that blocking Tsg101 after a person becomes infected with HIV could keep the virus from spreading and eventually leading to AIDS--the ``simplest'' scenario, according to Sunquist.

But Tsg101 is one protein in a ``pathway'' of proteins with similar functions. ``Other proteins in this pathway are surely involved (in HIV budding) too,'' the Utah researcher said.

He and his colleagues are now trying to weed out which proteins they might be. And, Sunquist noted, a number of viruses other than HIV may require Tsg101 for spreading among cells.

``There could be much more general implications,'' he said.