I (mpm at seqanal.mi.uky.edu) wrote:
: Prusiner's theory
: about species barriers would explain this. He has used molecular biology
: and transgenic animals to show that the longer latency period when infecting
: across different species is due the differences in sequences of the prion
: protein across different species. It appears that infectious protein
: "recruits" the endogenous prion protein in its propagation thru the CNS, and
: this takes longer if the sequences of the infectious protein and the endo-
: genous protein differ.
I'm sorry, I misstated the theory somewhat: going across species does not
necessarily require a LONGER latency, the infection simply presents a latency
peculiar to the species from which the infectious material came. This means
going from sheep to cow may present a longer or shorter latency than going
from sheep to sheep. I apologize for any confusion -- this theory is itself
sometimes confusing in its complexity. But I don't think this detracts from
its intellectual attractiveness as an explanation of the current data or from
its warning against the potential danger to humans.
Steven W. Barger, Ph.D.
Sanders-Brown Center on Aging