Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link
Volume 18, Number 6—June 2012

Etymologia: Prion

On This Page
Article Metrics

Cite This Article

To the Editor: The January 2012 Etymologia section might confuse readers because it incorrectly reports that “prion” describes a noninfectious agent (1). In fact, prion—pronounced pree'-on—is a term coined in 1982 by Nobel laureate Stanley Prusiner to describe the novel infectious agent responsible for scrapie, a transmissble neurodegenerative disorder of sheep and goats. He proposed his new term to underscore that the agents are “small proteinaceous infectious particles” resistant to procedures that attack nucleic acids (2). In his seminal article, he summarized experimental data indicating that the molecular properties of this infectious agent differed from those of other infectious agents, including viruses, viroids, and plasmids; he proposed the word prion to replace other terms then in circulation, such as “unconventional virus” or “unusual slow virus–like agent.”

Although Dr. Prusiner acknowledged that he could not exclude the possibility of a small nucleic acid contained within the interior of the prion particle, now 3 decades later, no nucleic acid in the agent has yet been identified. Increasingly accepted in the scientific community, prions are now considered to be a class of misfolded proteinaceous, infectious agents responsible for several types of human and animal transmissible spongiform encephalopathies. Their evolving defining characteristics classically include at least partial protease resistance, insolubility, and transmissibility. The term, prions, usually refers to the complete transmissible proteinaceous particles in nature or to their classically present, transmissible, protease-resistant oligomer cores, composed of protein fragments with molecular masses of ≈27–30 kDa.

Adding confusion to the terminology, it has become customary for prion researchers to refer to the normal nonpathogenic conformation of prions as “cellular prion proteins” (3). When these normal cellular prion precursors convert to pathogenic prion proteins, the transmissible conformations are characterized by β-pleated sheets rather than the normal α-helix structure, and they do not elicit an immune response (4).


Lawrence B. SchonbergerComments to Author  and Robert B. Schonberger
Author affiliations: Centers for Disease Control and Prevention, Atlanta, Georgia, USA (L.B. Schonberger); Yale University School of Medicine, New Haven, Connecticut, USA (R.B. Schonberger)



  1. Etymologia: prion. Emerg Infect Dis. 2012;18:157. DOIGoogle Scholar
  2. Prusiner  SB. Novel proteinaceous infectious particles cause scrapie. Science. 1982;216:13644. DOIPubMedGoogle Scholar
  3. Brown  P, Cervenakova  L. A lexicon (out of control). Lancet. 2005;365:122. DOIPubMedGoogle Scholar
  4. Dorland’s illustrated medical dictionary 2012, 32nd ed. Philadelphia: Elsevier Saunders; 2012. p. 1515.


Cite This Article

DOI: 10.3201/eid1806.120271

Related Links


Table of Contents – Volume 18, Number 6—June 2012

EID Search Options
presentation_01 Advanced Article Search – Search articles by author and/or keyword.
presentation_01 Articles by Country Search – Search articles by the topic country.
presentation_01 Article Type Search – Search articles by article type and issue.



Please use the form below to submit correspondence to the authors or contact them at the following address:

Lawrence B. Schonberger, Centers for Disease Control and Prevention, 1600 Clifton Rd NE, Mailstop A30, Atlanta, GA 30333, USA

Send To

10000 character(s) remaining.


Page created: May 11, 2012
Page updated: May 11, 2012
Page reviewed: May 11, 2012
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.