Prion transmissibility

Prateek K. Lala ak961 at freenet.HSC.Colorado.EDU
Thu Jul 13 09:39:41 EST 1995


In a previous article, umfunk15 at cc.umanitoba.ca (Duane James Funk) says:

>I have seceral quesitons:
>
>1. I assume the paper made an error saying CJD is caused by a virus and 
>not Dr. Korbinsky not knowing about prions.

   Prion diseases have historically been referred to as "slow-virus"
diseases even though the causative agent is not, per se, a virus. I would
think that Dr. Korbinsky does know about prions, but may have tailored his
comment to members of the general public who do not.

>2. If I am not mistaken there are familial forms of CJD where the prion 
>protein gene becomes mutated, correct?

   There are indeed familial forms of CJD, and the prion protein is
mutated. As you probably know, the mutant PrP exert a sort of
dominant-negative effect on normal proteins, changing their conformation
to the mutant phenotype.

>3. Finally, and most importantly, this business about blood 
>transmission.  From the papers I have read I think to myself 'Not Bloody 
>Likely' (Pun intended).  Aren't prions transmitted primarily in neural 
>tissue.

   As you say, prions are primarily transmitted through neural tissue
(neurosurgery, pituitary hormone transfusion, etc), but they are also
supposedly transmitted by corneal transplants.  How do the proteins end up
in the cornea?  Perhaps by traveling from the brain through the
vasculature (just a guess).  Blood transfusion doesn't seem all that
far-fetched to me, particularly in view of the fact that we don't really
know all that much about modes of transmission of prions.

Prateek Lala
4th year Microbiology, University of Toronto
-- 
The mind is like a TV set... when it goes blank, it's a good idea to turn
off the sound.   - Communication Briefings



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