Friday, December 21, 2012

Focus on Prion Assay

Prions are known to cause various neurodegenerative disorders or transmissible spongiform encephalopathies (TSEs) in animals and humans. They cause an abnormal folding of prion proteins mostly found in the brain, so when transmitted the disease causes brain damage and usually death. Some prion diseases include Scrapie in sheep; Chronic Wasting Disease (CWD) in deer; Bovine Spongiform Encephalopathy (BSE) in cows; and Creutzfeldt-Jakob Disease (CJD) in humans. In order to better understand these diseases the levels of prions present in an infection needs to be measured. A new assay, Real-Time Quaking Induced Conversion Assay (RT-QuIC), developed at Rocky Mountain Laboratories on a BMG LABTECH Omega plate reader is faster and higher throughput than previous bioassays using entire animals as hosts. Now the assay can be performed in a 96 well plate format in a few hours to a couple of days compared to several months or a year. For more information, see our application note .
RT-QuIC end-point dilution analysis of three 263K-inoculated preclinical 10 days post injection hamster BHs. In this case, the approximate SD50 was achieved with a 2 μl aliquot (the seed volume) of a 10E−5 dilution of the scrapie 10dpi 263K BH stock (green line). This gave an SD50/2μL of 10E5.5 and an SD50/g of 10E8.2. This figure was adapted from Rapid End-Point Quantitation of Prion Seeding Activity with Sensitivity Comparable to Bioassays