Sub-passage of DCIS organoids reconstituted the 3-D ductal and spheroid phenotypes, which reproducibly invaded inward from the surface of autologous stroma in organoid culture.
In total, nine homologous AHQ/AHQ to AHQ/AHQ intracerebral challenges have been performed as part of a larger study, one of which has already been reported [ 13] and three of which (cases 5-7) were sub-passages of this first case.
All of these, including the three sub-passage animals, have now succumbed to clinical disease.
Full vacuolation profiles could only be obtained for four of the five primary transmission cases, and one sub-passage animal.
Atypical scrapie is consistently transmissible within AHQ homozygous sheep, and the disease phenotype is preserved on sub-passage.
Sub-passage in mice or cell culture as well as cryopreservation of positive samples and permanent preparations were not done due to shortage of facilities.
Thus, further sub-passage of brains from scrapie-affected cattle into cattle is desirable to investigate the effects of passage on the stability of the phenotypes defined on primary transmission.
This paper provides data on further homologous AHQ/AHQ transmissions, including sub-passage of the initial case, and compares this with similar data from field cases of classical scrapie, and experimental bovine spongiform encephalopathy (BSE) in the same genotype.
This study demonstrates that atypical scrapie has distinct clinical, pathological and biochemical characteristics which are maintained on transmission and sub-passage, and which are distinct from other strains of transmissible spongiform encephalopathies in the same host genotype.
There was a slight shortening of mean incubation period between the initial experimentally challenged sheep (790 days) and those which succumbed following sub-passage (695 days), but the group sizes are too small to draw any robust conclusions from this observation.
The Montecchio cave, with passage length development of over 1700 m, is characterised by the presence of several sub-horizontal passages and many medium- and small-scale morphologies indicative of sulphuric acid speleogenesis (SAS).
