In vitro amplification of H-type atypical bovine spongiform encephalopathy by protein misfolding cyclic amplification

The in vitro amplification of prions by serial protein misfolding cyclic amplification has been shown to detect PrP^Sc to levels at least as sensitive as rodent bioassay but in a fraction of the time. Bovine spongiform encephalopathy is a zoonotic prion disease in cattle and has been shown to occur in 3 distinct forms, classical BSE (C-BSE) and 2 atypical BSE forms (L-BSE and H-BSE). Atypical forms are usually detected in asymptomatic, older cattle and are suggested to be spontaneous forms of the disease. Here, we show the development of a serial protein misfolding cyclic amplification method for the detection of H-BSE. The assay could detect PrP^Sc from 3 distinct experimental isolates of H-BSE, could detect PrP^Sc in as little as 1×10^?12 g of brain material and was highly specific. Additionally, the product of serial protein misfolding cyclic amplification at all dilutions of seed analyzed could be readily distinguished from L-BSE, which did not amplify, and C-BSE, which had PrP^Sc with distinct protease K-resistance and protease K-resistant PrP^Sc molecular weights.