Prion Diagnosis: Application of Real-Time Quaking-Induced Conversion

Abstract

Prions composed of pathogenic scrapie prion protein (PrP^Sc) are infectious pathogens that cause progressive neurological conditions known as prion diseases or transmissible spongiform encephalopathies. Although these diseases pose considerable risk to public health, procedures for early diagnosis have not been established. One of the most recent attempts at sensitive and specific detection of prions is the real-time quaking-induced conversion (RT-QuIC) method, which measures the activity of PrP^Sc aggregates or amyloid formation triggered by PrP^Sc seeds in the presence of recombinant PrP. In this review, we summarize prions, prion diseases, and current approaches to diagnosis, including the principle, conditions for assay performance, and current diagnostic applications of RT-QuIC.

Figure 1

RT-QuIC data. (a) A representative RT-QuIC response. A set of RT-QuIC quadruple reactions was performed with mouse rPrP (89–231) and PrP^Sc seeds from ScN2a cells diluted 5 × 10⁻⁴-fold. RT-QuIC was performed using a modified version of the method described by Atarashi et al. [21]. The average ThT fluorescence was plotted against assay time. (b) Differences in length of lag phase. (c) Differences in amyloid formation rate. (d) Differences in ThT fluorescence maxima. (e) Differences in integrated area under the curve. Averages and standard deviations (error bars) were calculated using multiple data sets (n = 4). Student's t-test was used for statistical analysis. A p value < 0.05 (∗) was considered statistically significant.