TSE occurrence in VRQ/VRQ TSE free sheep transfused with blood labile products prepared from Scrapie infected sheep.

Each whole blood pool was constituted by mixing 700 mL from 3 VRQ/VRQ sheep orally inoculated with PG127 classical scrapie isolate. Aliquots of whole blood were processed according to the design described in Figure 1. Obtained products were then transfused in VRQ/VRQ TSE free recipient sheep. Recipients were monitored for clinical TSE occurrence. Clinically affected animals were culled when displaying locomotor difficulties that could impair their abilities to feed. The remaining apparently healthy recipients were killed 400 days after transfusion. Systematic detection of abnormal PrP (using both immunohistochemistry and western-blot) in lymphoid tissues (LRS) and central nervous system (CNS) was carried out in recipients as to establish their status.