March 4, 2005
Researchers report they have created a modified HIV strain that can infect mice animals that usually provide an excellent model for studying human diseases. The new "chimeric" virus, EcoHIV, was engineered by switching out the HIV gene that encodes the surface protein gp120, which recognizes human cells, with a gp80 gene from a mouse leukemia virus, according to Dr. Mary Jane Potash, of New York's Columbia University Medical Center, and her research team.
EcoHIV infected about 75 percent of the mice tested, an efficiency rate comparable with that of HIV in humans. The EcoHIV infection was present in immune cells and white blood cells, the spleen, abdominal cavity and brain. "In some mice the viral [level] is going up five months after infection, which means there is active replication going on," said Potash. "And since we can detect virus in a week, when we have drugs to test we can potentially see an effect in vivo as fast as you can in culture."
"If there's one place we ought to be able to discover how to get a good response it's in a mouse where you have live virus infection that you might be able to control," Potash said. "One of the greatest advantages of this model is that the virus, at least in culture, does not infect human cells, so it ought to be a lot safer to use than HIV."