Virus unmasked

 作者:单于岢     |      日期:2019-03-08 02:20:00
By Philip Cohen in San Francisco MAJOR steps towards understanding how the dangerous hepatitis C virus copies itself and outwits medical treatment have been made in two new studies. More than 150 million people worldwide have been infected by HCV. More than three-quarters of them develop a chronic liver infection. But the virus is very reluctant to replicate in the lab. So Ralf Bartenschlager of the University of Mainz in Germany and his colleagues tried a new tactic. They genetically engineered HCV DNA to include an antibiotic resistance gene, then introduced the engineered virus into cells. By using the antibiotic, the team could kill off cells the virus failed to invade, and select only those in which the virus replicated. As expected, the virus rarely infected cells. But when it did, it replicated efficiently ( Science, vol 285, p 110). “With these cells in hand, there is a lot we can do,” says Bartenschlager. The system could be used to test how well different drugs interrupt replication of the virus. Interferon is the standard treatment for HCV. It switches on a protein called PKR that shuts down production of proteins and viruses in infected cells. But this drug works in less than half of patients. In Science(vol 285, p 107), a team led by Michael Lai of the University of Southern California in Los Angeles explains why,