One of the new in vitro tests, called the Standard Scrapie Cell Assay, measures prion infectivity levels in a highly accurate and extremely rapid way, producing results in less than two weeks. The second test, called the Cell Panel Assay, allows researchers to quickly distinguish between several prion strains in various cells lines. Using the new assays, the scientists were able to show that four different cell lines exhibited widely different responses to four different strains of the infectious protein particles.
The research is being published in an advanced online edition of the Proceedings of the National Academy of Sciences the week of December 3, 2007.
These new assays vastly accelerate the measurement of prion infectivity and the determination of those cell lines that are able to sustain high infection rates of some prion strains, said Sukhvir P. Mahal, an author of the study who is a senior staff scientist in the laboratory of Charles Weissmann, chair of the Scripps Florida Department of Infectology. The current test, which takes anywhere from 150 to 250 days and involves large numbers of laboratory mice, is slow, imprecise, and expensive. Our new assays will replace the current mouse brain-bioassays.
The current method of measurement and identification involves injecting a prion-containing sample into the brains of mice and then waiting to see how long it takes for the animals to succumb to disease; the higher the prion level, the less time it takes for them to become lethally infected.
In contrast, the new Standard Scrapie Cell Assay is based on prion-susceptible cell lines. In the test, cells are exposed to prions and then the infected cells are identified and counted using automated imaging equipment.
A Unique Pathogen
Prions (the name stands for proteinaceous infectious particles) are unique infectious pathogens associated with some 15 different diseases, including Bovine Spongiform En
|Contact: Keith McKeown|
Scripps Research Institute