Prions are not readily transmittable from species to species, but once they have broken through the species barrier they can rapidly adapt and become contagious within the species. Intensive work is now underway to find new, more sensitive methods for detecting these potentially deadly protein structures and distinguish between various strains.
The research team infected genetically identical laboratory mice with BSE, scrapie, and CWD for several generations in a row. Gradually new strains of prions emerge, making the diseases more fatal to the mice. Tissue samples from mice were examined using the newly developed fluorescent molecule, which seeks out and binds with prions. This is signaled by a shift in color. By tweaking the molecule, the team has been able to get it to show different colors depending on the structure of the prioneach prion strain emits its own optical fingerprint. This is an important difference compared with other techniques used to find prions such as antibodies and the well-known stain Congo red.
The technique has also proven to work well on tissue sections from dead animals, such as cows infected with BSE. Now the scientists want to move on and look for alternative sample-taking methods for diagnosing and tracking prion diseases in humans in early stages. The method would then be useful for screening blood products, since there is a risk that people can be carriers of prions without having any symptoms of disease. In the U.K. it was discovered that 66 people had received blood from blood donors who were infected with the human form of BSE and among them, four individuals have been shown to be infected.
"Using our methods, we can directly see the structure of the prions and thereby deduce the disease," says Peter Nilsson, one of the lead authors.
"For us researchers it is truly exciting to use this technique to understand more about both prions and other defectively folded proteins that give rise to similar disorders, such as Alzheimer's," says Peter Hammarström, research director of the prion laboratory at Linköping.
COMPAMED.de; Source: The Swedish Research Council