AA # 5

 Greedy Virus Helps Spread Disease

The vaccinia virus seems to have an interesting invasion method. “‘Mine, all mine!’ That's what the vaccinia virus seems to be saying after it invades a cell and prevents its companions from following suit.” The strategy actually helps the virus spread. This discovery may give raise to innovative ways to combat viral infections. Vaccinia doesn't cause diseases in humans but it has actually aided us in fighting viral infections. It has a resemblance to the smallpox virus. Researchers were able to use it as a vaccine for the small pox virus until it was eradicated in the late 1970’s. Vaccinia is continually researched in hope of developing other vaccines. Virologist Geoffrey Smith of Imperial College London noticed that vaccinia spread four times faster than its replication cycle. "No one seemed to have done the arithmetic," Smith says. So, Smith and his colleagues decided to research this more. They discovered that vaccinia produces two proteins after it infects a cell. This result in a superinfection; the vaccinia proteins form a complex on the cell's surface that inhibits other vaccinia virus from entering the cell. As a vaccinia viruses come closer, long projections of actin, shoot out from the cell membrane. This shoos the virus away. Many other viruses, such as herpes simplex virus, have a similar infection strategy. If researchers could utilize the same protein complex as vaccinia, it could help in fighting these infections by blocking the interaction of the two proteins.

S. Lundin, “Greedy Virus Helps Spread Disease,” Science, 1/22/2010. http://news.sciencemag.org/sciencenow/2010/01/22-02.html, [2/19/2010].