Table 2. Titration of whole blood from PG127 scrapie infected sheep by transfusion into VRQ/VRQ TSE-free recipient sheep.

	200 mL		20 mL		2 mL		0.2 mL
	dpi	PrPSc	dpi	PrPSc	dpi	PrPSc	dpi	PrPSc
D1	188	+	197	+	207	+	210	+
D2	176	+	184	+	186	+	203	+
D3	173	+	203	+	214	+	>450	+
D4	169	+	178	+	193	+	214	+

Four scrapie susceptible VRQ/VRQ sheep between 6 and 10 months of age (identified as D1, D2, D3 and D4) were orally challenged with 2 grams of sheep-scrapie strain PG127 infected brain homogenate containing 10^6.6 ID₅₀/g as measured by IC inoculation of tg338 mice. These animals were euthanized at 227 days, 256 days, 221 days and 226 days post inoculation (dpi) respectively with symptomatic scrapie. Scrapie infection was confirmed by histopathological detection of vacuolar changes in the central nervous system and by immunohistochemical detection of abnormal PrP deposits in the central nervous system and lymphoid tissues. Whole blood had been collected from each donor at 210 dpi. Donors developed clinical scrapie two to five weeks following blood collection. 200 mL, 20 mL, 2 mL and 0.2 mL were intravenously administrated (jugular vein) to TSE Free Cheviot VRQ/VRQ recipients, within 6 hours following collection. Recipients were observed until occurrence of clinical signs. At 450 days post inoculation the single recipient that was still alive was euthanized. This animal was clinically normal and healthy. All transfusion recipients were tested for presence of abnormal PrP deposition in brain and various lymphoid tissues by immunohistochemistry and western blot. All recipients, including the asymptomatic survivor to 450 days displayed evidence of infection. Incubation periods in recipients are presented as days post inoculation (dpi).