Intracerebral inoculation of tg338 mice with VRQ/VRQ sheep whole blood, plasma and red blood cell concentrate.

Blood was collected from three TSE free VRQ/VRQ donor sheep that had been orally challenged with PG127 scrapie (D1, D2, D3) and one TSE free VRQ/VRQ control sheep (C1). The date of collection from the infected animals was 210 days post inoculation. Donors developed clinical scrapie two to five weeks following blood collection. They were euthanized at 227 days, 256 days, 221 days respectively. Whole blood, plasma, red blood cell concentrate (RBC) were each inoculated intracerebrally into 18 tg338 mice (20 µL per mouse). For each component, the volume of whole blood corresponding to the volume inoculated is given. Mice were euthanized when they showed clinical signs of infection or after 250 dpi. Mice were considered infected when abnormal PrP depositions were detected in brain. Infectious titers were estimated using limiting dilution titration method (application of Poisson model) described by Brown et al [23]. Infectious titers are given as the most likely infectious titer and, in parentheses, the values of the lower and upper limits of the 95% confidence interval.