Abstract
Prions, infectious agents causing transmissible spongiform encephalopathy (TSE), are composed primarily of the pathogenic form (PrPSc) of the host-encoded prion protein. Although very low levels of infectivity have been detected in urine from scrapie-infected rodents, no reports of urinary PrPSc have been substantiated. Studies on the dynamics of urinary PrPSc during infection are needed to ensure the safety of urine-derived biopharmaceuticals and to assess the possible horizontal transmission of prion diseases. Using the protein misfolding cyclic amplification technique, a time-course study of urinary excretion and blood levels of PrPSc was performed in Sc237-infected hamsters and a high rate of PrPSc excretion was found during the terminal stage of the disease. Following oral administration, PrPSc was present in all buffy coat samples examined; it was also present in most of the plasma samples obtained from hamsters in the symptomatic stage. PrPSc was excreted in urine for a few days after oral administration; subsequently, urinary PrPSc was not detected until the terminal disease stage. These results represent the first biochemical detection of PrPSc in urine from TSE-infected animals.