"By altering a single lysine residue, you not only affect the virus' replication, but also the accuracy with which it is copied," he said. "A virus replication speed and accuracy is optimized; there is a delicate balance. We have defined the optima for poliovirus but where that balance is going to be for different viruses, we do not yet know."
Since all viruses have a similar mechanism regulating their replication, Cameron says the discovery may represent a universal mechanism of weakening other viruses causing diseases such as influenza, SARS, Dengue fever and the West Nile Virus for developing vaccines.
"All standard approaches for vaccine development take years," said Cameron. "It is all a random trial and error process to get an attenuated weakened virus that may be treated as a potential vaccine candidate. There is no direct method."
Positive strand RNA viruses those with only one gene such as SARS coronavirus, and hepatitis C virus compound the problem. "The gene makes a protein that gets processed into a lot of different functions," said Cameron. "There is no gene to delete." But these viruses do have an amino acid similar to the residue identified in poliovirus, which can be replaced to produce weak variants. These new strains are quickly neutralized by the immune system, providing protection against the more virulent strains.
The Penn State Scientist says his findings could help avoid the long time it takes to create vaccines, and might help mount a more effective response against ever-changing viruses such as influenza, as well as emerging and re-emerging viruses such as SARS coronavirus, West Nile Virus and Dengue virus.
He added that the technique of
|Contact: Amitabh Avasthi|