59.0.1. Prions

Introduction

Synonym(s): subviral agents of spongiform encephalitis. Comments: Prions are small, proteinaceous infectious particles that resist inactivation by procedures which affect nucleic acids. To date, no detectable nucleic acids of any kind and no virus-like particles have been associated with prions. Prions cause scrapie and other spongiform encephalopathies of animals and humans. Description is on the taxonomic level of family. Taxon infects vertebrates.

Properties of Virion

Morphology. Virions found (in microsomal fractions of brain material); rod-shaped (smooth, almost ribbon-like). Nucleocapsids (25-)165(-550) nm long; 11 nm in diameter. Microsomal fractions from infected tissues enriched for prion infectivity contain numerous membrane vesicles; detergent extraction and limited proteolysis of brain microsomes generate rod-shaped particles. The rods are smooth, almost ribbon-like, and infrequently are twisted. The rods resemble purified amyloid, both ultrastructurally and histochemically. The rods are not considered the infectious entity since large PrP 27-30 polymers are not required for infectivity.

References. The following references are cited in the Sixth ICTV Report: rf_prion.htm.

Data sources and contributors. The above description has been compiled from the data presented in the Sixth ICTV Report by Prusiner SB, Baldwin M, Collinge J, DeArmond SJ, Marsh R, Tateishi J, Weissmann C.

Description generated automatically from DELTA-format data.

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