Infuenza Specialist Group

It has been known for some time that whether an influenza virus infects humans depends on whether its hemagglutinin, a protein found on the virus surface, can bind to particular chemical receptors (sugar molecules known as glycans) on cells in the respiratory tract. Human respiratory cells have receptors that have chemically different linkages than those in birds. Until now, it was believed that a genetic switch that allows the virus to bind to receptors with the correct chemical linkage is responsible for avian viruses' ability to jump to humans. However, a new study at MIT study shows that the shape, or topology, of the receptor also determines whether it will infect humans. The human glycan receptors come in two shapes-one that resembles an umbrella, and another that resembles a cone. The MIT team found that to infect humans, flu viruses must bind to the umbrella-shaped receptor.

The discovery may help scientist’s better monitor changes in the H5N1avian influenza virus that could trigger a deadly pandemic in humans; and it may lead to better ways to fight it. "We now know what to look for," said Prof Sasisekharan, whose study appears in the Journal Nature Biotechnology. 

Content Updated ( Friday, 18 January 2008 )