BSE versus Creutzveld-Jacobs-syndrome

[Ian A. York]

In article <4k4dj3$3gae at pegasus.unm.edu>,  <bhjelle at unm.edu> wrote:
>
>The paper to which I refer is in Nature 1995 vol 378
>pages 761-2 (with commentary in the same issue page 759).
>They claim to have produced human PrP Sc in heterozygous
>mouse/human PrP transgenics. Obviously, this is not the
>same as human/human homozygotes. The bovine protein may
>have induced murine PrP Sc which then induced human PrP
>Sc. Has the human/human homozygote transgenic work been

Sorry, Brian, I think you've misinterpreted that paper.  The BSE did NOT
induce the human PrP-Sc.  (From the abstract: "  Incubation periods to BSE
in transgenic mice are not shortened by expression of human PrP, and only
mouse PrP(Sc) is produced in response to such challenge.")

Your statement that "they claim to have produced human PrP Sc in
heterozygous mouse/human PrP transgenics" is exactly correct, but that
human PrP-Sc was in response to an innoculation with human CJD prions, not
BSE.  From the paper: "We first studied mice that express both human and
mouse PrP to determine whether, on challenge with Creutzfeldt-Jacob
disease (CJD) inocula, they could produce human PrP-Sc and human prions.
... Here we describe primary transmission and second passage of a single 
isolate of human prions from a CJD case."  They also transmitted several 
other prions from other human prion diseases.  

After inoculation with BSE: "Human PrP-Sc was not detected, suggesting
that these mice produced only mouse prions in response to BSE challenge." 

As far as the human/null cross (human prion only)  mice, the paper noted 
that after inoculation with BSE "these mice remain well at 264 days 
post-inoculation.  Although this period is too short to draw any firm 
conclusions, the incubation period is already approxiamtely 60 days 
longer than for CJD in mice of this genotype.  The end point of this 
study may still be 600-700 days away if these mice die of old age rather 
than illness."

Ian 

-- 
      Ian York   (iayork at panix.com)  <http://www.panix.com/~iayork/>
      "-but as he was a York, I am rather inclined to suppose him a
       very respectable Man." -Jane Austen, The History of England