A rapid and very sensitive technique for the detection of infectious prion proteins is reported online in Nature Methods.
Prions, the cause of neurodegenerative diseases such as mad cow, scrapie in sheep or Creutzfeldt-Jakob disease in humans (CJD), are infectious proteins in the brain. They are so similar to their healthy cellular counterparts that they cannot be distinguished by antibodies, making their detection difficult.
To develop methods for prion detection scientists have taken advantage of the fact that prions will convert certain normally folded protein into infectious aggregates which can be more easily measured. If a sample contains prions they will trigger protein aggregation in a healthy brain tissue substrate which can then be measured. Downsides of this technique are that it takes weeks to do and requires whole brain tissue, which is more difficult to obtain.
Byron Caughey and colleagues have improved matters; their adaptation allows the use of recombinant protein rather than brain tissue as a substrate for the aggregation reaction. They can distinguish between prion-infected and healthy hamsters using only minute amounts of body fluids in 2-3 days.
Their method will not only be of considerable interest to the developers of diagnostic assays, it will also allow the study of components affecting prion aggregation and the screening for inhibitors of the process.
Byron Caughey (National Institute of Allergy and Infectious Diseases, Bethesda, MA, USA)
Abstract available online.
(C) Nature Methods press release.
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