The present invention relates to methods for the inhibition of
disease-associated prion formation and propagation. Such methods are
based on inhibition of PrP.sup.Sc cleavage, which prevents PrP.sup.Sc
accumulation and results in reduced prion titers. More particularly, the
present invention relates to endoproteolytic cleavage of PrP.sup.Sc by
calpain, a calcium (Ca.sup.2+)-activated cysteine protease, and its
inhibition.