Pittsburgh -- U.S. scientists have discovered how the human immunodeficiency virus can so easily enter the body's immune cells.

Carnegie Mellon University researchers found that after HIV docks onto a host cell, it dramatically lowers the energy required for a cell membrane to bend, thereby making it easier for the virus to infect immune cells.

"We found that HIV fusion peptide dramatically decreases the amount of energy needed to bend a cell-like membrane," said research Associate Professor Stephanie Tristram-Nagle. "This helps membranes to curve, a necessary step for HIV to fuse with an immune cell as it infects it."

She said the discovery helps explain, in part, how HIV infection occurs so readily.

"Our findings definitely will change how theoreticians think about virus-cell interactions," she added. "This same phenomenon could provide a general way that viruses use to infect cells, so it will be exciting to look at other viral systems with our experimental method."

The research has been accepted for publication in the Biophysical Journal.

Copyright 2007 by United Press International.