In practice, and accommodating for transgene expression levels, both PrP(S3) and PrP(H95G) alleles led to curtailed incubation periods upon prion inoculation, with a focus upon altered toxicity rather than elevated infectious titre; indeed, serial passage of infectivity and lower spot counts in a scrapie cell assay indicated depressed infectious titres for PrP(S3) [26] while inocula from TgPrP(H95G) mice produced typical incubation times in wt mice (Table 1). This evidence concerns the gene PRNP and scrapie.