2003 Volume 49 Issue 4 Pages 267-272
Prion protein (PrP) exists in two different isoforms; a normal cellular isoform (PrPC) and an abnormal infectious isoform (PrPSc), the latter is a causative agent of prion disease such as Bovine Spongiform Encephalopathy (BSE, mad cow disease) and Creutzfeldt-Jakob disease (CJD). Great concern about variant CJD, which is caused by ingesting BSE-contaminated products, is also emerging and spreading over Japan since the first BSE-affected cattle was identified in September, 2001. The amino acid sequences of PrPC and PrPSc are identical, but their conformations are rather different; PrPC is rich in the non β-sheet isoform while PrPSc is rich in the β-sheet isoform. Our prion research focuses on further understanding such an unprecedented mechanism by identifying auxiliary factor(s) other than PrPC and PrPSc. These studies also help us to develop "therapeutics and prevention methods" for prion disease. Three major trials; genetic manipulation with dominant negative mutant PrPC gene working against a hypothetical host-specific factor, antibody therapy with anti-PrP antibodies which block PrPC-PrPSc binding, and PrPSc unfolding therapy with a novel-class molecular chaperone, are currently underway.
