Each year, about 40,000 children are born infected with human cytomegalovirus, or CMV, and about 8,000 of these children suffer permanent disabilities due to the virus - almost one an hour.
These disabilities can include hearing loss, vision loss, mental disability, a lack of coordination, and seizures. According to the Centers for Disease Control and Prevention, CMV is as common a cause of serious disability as Down syndrome, fetal alcohol syndrome, or neural tube defects.
Because of the dangers posed by the virus to infants, the Institute of Medicine has declared that development of a CMV vaccine should be one of the highest priorities for vaccine makers. Now, in a new study in the August 1 issue of The Journal of Virology, researchers at The Wistar Institute outline an innovative approach that could be used to create such a vaccine.
The Wistar scientists began with the observation that mice harbor a species-specific form of CMV that is unable to sustain an infection in humans and is completely harmless to them. They then asked whether, using recombinant technologies, there might not be a way to shift the mouse-specific virus closer to the human-specific virus to generate a version of the virus able to elicit a protective immune response but not a dangerous infection in humans.
With this goal, the researchers began to systematically introduce selected genes from human CMV into the genome of mouse CMV in the laboratory. The result was a novel form of CMV virus that infected human cells well enough that it might trigger an immune response but not well enough to sustain an infection.
"It should be possible to develop a safe and effective CMV vaccine using the method we've described in our study," says Gerd G. Maul, Ph.D., a professor in the Gene Expression and Regulation Program at Wistar and senior author on the new study. "Success will depend on achieving a certain balance between the immune-stimulating genes from the human virus and the basic safety of the mouse virus."