leach at mbcrr.harvard.edu (Martin Leach) writes:
>In article <R.Burge.54.000B9573 at bay.cc.kcl.ac.uk>, R.Burge at bay.cc.kcl.ac.uk>(Richard Burge) wrote:
>> Breaking off at a tangent - just how does one explain how an ingested prion
>> is infectious anyway? I can't see it getting past the stomach, so I would
>> imagine it is getting into the bloodstream somehow. The reactive part of the
>> prion protein is about 27kD, however - does this _really_ get past the BBB?
>I believe parts of prion are protease resistant - hence it gets past the
Rupture of the alimentary canal is suggested as necessary for the agent to reach
the bloodstream, hence it is indeed a large part of the barrier to infection.
As for the Blood-Brain-Barrier, ah, well...
Even when exp'tal animals are intracerebrally inoculated, the first place the
prion protein shows up is the spleen (particularly the 'follicular dendritic
cells', but don't press me any further on that aspect!). So that demonstrates
_a_ crossing of the BBB even if it is in the opposite direction. I don't recall
anyone having exlpicitly said so, but I presume the cells of the immune system
with their still-little-understood means of crossing the BBB may be carrying the
resistant particle (which they, too, are unable to break down).
Heh. I may be wrong. (:>
Nev Percy ; spbcnsp at ucl.ac.uk