In contrast to other studies describing inoculation of recPrP fibrils [12, 13, 37, 39, 40, 42, 43, 61, 66], we saw no TSE disease in recipient mice, but did reproduce the seeding of PrP amyloid plaques observed in our previous work following inoculation of brain extract containing in vivo-derived amyloid fibrils. This evidence concerns the gene PRNP and human prion disease.