Objective: To establish a methodology of protein misfolding cyclic amplification (PMCA) and utilize in the detection of PrP(Sc) in brain tissues from prion diseases.
Methods: Different amounts of Scrapie 263K agent bulk were mixed with brain homogenates of health hamsters and treated with repeated incubation/sonication for 10 to 15 cycles. The proteinase K-resistant PrP(Sc) was evaluated with Western Blot.
Results: In this experimental situation, 263K agent replicated rapidly in vitro, utilizing hamsters' brains as the medium. With the established PrP(Sc)-PMCA technique, PrP(Sc) signals in the preparations containing less than 10(-5) diluted 263K bulk could be detected. Compared with conveniently used immuno-blot assay, the sensitivity of PrP(Sc)-PMCA for PrP(Sc) was 10(5) to 10(6)-fold increased. It has been also shown that homogenates of cerebellar and brain stem could be used as the medium for PrP(Sc) replication.
Conclusion: A rapidly replicating method for PrP(Sc), PrP(Sc)-PMCA, was successfully established, providing a new approach for early diagnosis of prion diseases and research on the biological features of prion.