Observations on thermostable subpopulations of the unconventional agents that cause transmissible degenerative encephalopathies

• Published in: Veterinary microbiology Vol. 64; no. 1; pp. 33 - 38
• Main Authors: Taylor, D.M, Fernie, K, McConnell, I, Steele, P.J
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.1998; Elsevier Science
• Subjects: Action of physical and chemical agents; AGENT DE LA TREMBLANTE DU MOUTON; AGENTE DE TEMBLADERA DE LOS OVINOS; Animals; Biological and medical sciences; Brain - immunology; Brain - pathology; CALOR; CHALEUR; Cricetinae; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; ENCEFALOPATIA ESPONGIFORME; ENCEPHALOPATHIE SPONGIFORME; Fundamental and applied biological sciences. Psychology; HEAT; Hot Temperature; Medical sciences; Mesocricetus; Microbiology; Neurology; PRION; PRIONES; PRIONS; Prions - chemistry; PrPSc Proteins - chemistry; PrPSc Proteins - immunology; RESISTANCE A LA TEMPERATURE; RESISTENCIA A LA TEMPERATURA; Scrapie - immunology; Scrapie - pathology; SCRAPIE AGENT; SPONGIFORM ENCEPHALOPATHY; TEMPERATURE RESISTANCE; Thermostability; Transmissible degenerative encephalopathies; Virology; Thermostability; Transmissible degenerative encephalopathies; Scrapie agent; Nervous system diseases; Temperature; Central nervous system disease; Environmental factor; Degenerative disease; Prion; Spongiform encephalopathy; Veterinary; Inactivation; Thermal stability; Cerebral disorder
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/S0378-1135(98)00257-0

When scrapie agent is exposed to partially inactivating autoclave cycles, the fraction of infectivity that survives remains thermostable during relatively long periods of autoclaving. This resistant subpopulation can also be differentiated from the main population by its prolonged incubation periods in assay animals, compared with control material. Stabilisation of this subpopulation may occur through the smearing and drying of infected tissue that can occur prior to autoclaving, in which the disease-specific form of PrP protein (PrP Sc) could become rapidly heat-fixed. This may paradoxically be what protects this fraction of PrP Sc from further inactivation during autoclaving. Data are presented showing that the thermostability acquired by the resistant subpopulation is a stable characteristic; autoclaving for a second time results in very little further loss of infectivity. These observations suggest that inactivation procedures that do not involve rapid and effective fixation of PrP Sc may be better candidates for dealing effectively with scrapie-like agents.