Table 2.

Scrapie strains retain transmission properties after passage in PrP transgenic Drosophila

Scrapie strain	Original strain isolated in tg338 mice		Drosophila-passaged strain isolated in tg338 mice
			First passage		Second passage
	Attack rate	IP	Attack rate	IP	Attack rate	IP
PG127	6/6	61 ± 2	6/6	87 ± 4	6/6	59 ± 1
Pa59	6/6	143 ± 3	6/6	187 ± 4	6/6	142 ± 1
Apl338	6/6	631 ± 83	3/5	642 ± 57	NA	NA

The ovine classical scrapie prion strains PG127 and Apl₃₃₈ (isolated in ovine VRQ tg338 mice) and Pa₅₉ (isolated in ovine ARQ tg59 mice) were transmitted to tg338 ovine PrP transgenic mice. The ovine classical scrapie prion strains PG127, Pa₅₉ or Apl₃₃₈ were transmitted to tg338 ovine PrP transgenic mice. In parallel, Actin × VRQ(GPI) PrP transgenic (VRQ) Drosophila were exposed to the PG127 and Apl_338, prion strains, and Elav × ARQ(GPI) PrP transgenic (ARQ) Drosophila were exposed to the Pa₅₉ prion strain, at the larval stage. Head homogenates were prepared from adult flies aged 30 days and serially transmitted in tg338 mice (two iterative passages) by intracerebral inoculation. Mice were euthanized when they showed clinical signs of prion infection and after 250 days for those that did not develop clinical disease. Mice were considered positive for prion disease when PK-resistant PrP27–30 was detected in brain tissue by western blot. The attack rate (number of prion positive mice/total number of mice inoculated) is reported for each treatment group. The incubation period (IP) for inoculated mice, which represents the mean time from inoculation to euthanasia for each inoculated group of animals, is reported in days ± SD. NA = data not available, still ongoing.