Study shows infectious prions can arise spontaneously in normal brain tissue

July 27, 2010

Scientists from The Scripps Research Institute in Florida and the University College London (UCL) Institute of Neurology in England have shown for the first time that abnormal prions, bits of infectious protein that can cause fatal neurodegenerative disease, can suddenly erupt from healthy brain tissue, promoted by contact with steel surfaces.

Mammalian cells normally produce harmless cellular prion protein (PrPC). Following prion infection, the abnormal or misfolded prion protein (PrPSc) converts PrPC into a likeness of itself, by causing it to change its conformation or shape. The end-stage consists of large aggregates of these misfolded proteins, which cause massive tissue and cell damage.

In the new study, the scientists used the Scrapie Cell Assay, a test that is highly sensitive to minute quantities of prions. They found that when normal prion protein is coated onto steel wires and brought into contact with cultured cells, a small but significant proportion of the coated wires cause prion infection of the cells, and when transferred to mice, they continue to spawn the disease.

They noted that an alternative interpretation of the results is that infectious prions are naturally present in the brain at levels not detectable by conventional methods, and are normally destroyed at the same rate they are created. If that is the case, metal surfaces could be acting to concentrate the infectious prions to the extent that they became quantifiable by the team’s testing methods.

The findings are being published the week of July 26, 2010, in an advance, online edition of the journalĀ Proceedings of the National Academy of Sciences (PNAS) in Spontaneous generation of mammalian prions (open access).

More info: Scripps Research Institute news