PRNP and human prion disease: Recent studies amplified protease-resistant PrP or fibrillary PrP-related peptides in vitro, allowing detection of very small amounts of PrPTSE in tissues and some fluids of humans and animals with TSEs; those techniques could be used to study TSE pathogenesis and transmission, but are currently employed mainly as research tests to help diagnose human TSEs antemortem [7].