"The altered virus does not grow in any normal cells," says Kawaoka. "We made cells that express the VP30 protein and the virus can grow in those cells because the missing protein is provided by the cell."
It took years, Kawaoka explains, to find which viral protein was not toxic to cells and could thus be used to develop a system, using monkey kidney cells, to confine the virus.
And Kawaoka, an internationally noted virologist, is convinced of the safety of the new system: "We did this work in a BSL 4, and the altered cells didn't produce any infectious virus after many passages or replication cycles."
With the exception that it is unable to grow in anything but cells engineered to express the VP30 protein, the virus is identical to the pathogen found in the wild, making it ideal for studies of basic biology, vaccine development and screening for antiviral compounds.
"This system can be used for drug screening and for vaccine production," Kawaoka says, noting that getting the equipment and compounds for such work into a BSL 4 lab is extremely difficult. "High throughput screening (for drugs) in a BSL 4 is almost impossible."
Currently, live Ebola virus can be studied only in a BSL 4 laboratory. Any proposal to permit studying the pathogen in lower safety level labs is certain to generate controversy.
But according to Kawaoka, making the agent available for study to a broader cross section of science is essential for thwarting the virus that kills a high percentage of its victims because there is now no defense against it. A new strain of Ebola, which so far has emerged only in remote areas of the world, was recently identified in U
|Contact: Yoshihiro Kawaoka|
University of Wisconsin-Madison