CMAJ/JAMC Letters
Correspondance

 

BSE, variant CJD and infectious proteins

CMAJ 1998;158:302-3
The Nov. 15, 1997, issue of CMAJ featured 4 articles on Creutzfeldt-Jakob disease (CJD), but none of the articles mentioned related work on "protein-like previral infectious particles." I would like to take this opportunity to correct that omission.

In 1982, at the same time that Dr. Stanley Prusiner published his paper on prions,1 a similar mechanism for replication of the infectious proteins of scrapie was proposed,2 and the term protovirins (protein-like previral infectious particles) was suggested for these unusual infectious agents.

Two recent reports in Nature3,4 outlined conclusive evidence from research centres in the UK that the agent causing bovine spongiform encephalopathy (BSE) is also responsible for variant CJD (vCJD). In the same issue of Nature, Jeffrey Almond and John Pattison commented on the possibility that the proteinaceous infectious agent in BSE and vCJD might have a cofactor.5 This cofactor may consist of a short chain of nucleotides attached to the infectious protein and may act as a signal primer for the agent on the host's DNA. I therefore suggest that "protovirin" would be a more appropriate name than "prion" for these unusual infectious agents, which cause transmissible spongiform encephalopathies.

Concern was voiced in Canada in 1990 about the strong possibility that BSE might spread to humans,6 and Agriculture Canada was urged at that time to slaughter all cattle that had been imported from the UK.7 To the credit of that ministry, the recommended action was taken in 1991, after an animal imported from the UK was found to have BSE. Since then, no further cases of BSE have been reported in Canada.

Peter K. Lewin, MD, MSc
Hospital for Sick Children
Toronto, Ont.
p.lewin@utoronto.ca

References

  1. Prusiner SB. Novel proteinaceous infectious particles cause scrapie. Science 1982;216:136-44.
  2. Lewin PK. Infectious peptides: postulated mechanisms of protovirin replication in scrapie. CMAJ 1982;127:471-2.
  3. Hill AF, Desbruslais M, Joiner S, Sidle KCL, Gowland I, Collinge J. The same prion strain causes vCJD and BSE. Nature 1997;390:448-50.
  4. Bruce ME, Will RG, Ironside JW, McConnell I, Drummond D, Suttie A, et al. Transmissions to mice indicate that "new variant" CJD is caused by a BSE agent. Nature 1997;390:498-501.
  5. Almond J, Pattison J. Protein only prions. Nature 1997;389:437-8.
  6. Lewin PK. Scrapie and human neurodegenerative disease [letter]. CMAJ 1990;142:928.
  7. Prescient pediatrician forecasts mad-cow crisis. Can Med Assoc J 1996;155:1721.

Comments Send a letter to the editor responding to this letter
Envoyez une lettre à la rédaction au sujet de cette lettre

| CMAJ February 10, 1998 (vol 158, no 3) / JAMC le 10 février 1998 (vol 158, no 3) |