Figure 4

PMCA of VPSPr, GSS and sCJD PrP ^Sc . Brain homogenate prepared from the frontal cortex (FC) and cerebellum (Cb) of VPSPr cases 2 and 3, and frontal cortex from two cases of GSS (associated with ~8 kDa and type 1 PrP^res, respectively) and a case of sCJD VV2 were used to seed single-round PMCA reactions. The brain homogenates used as substrates are as indicated in the figure, and were either non-CJD human post mortem brain frontal cortex tissue (upper panel) or humanised transgenic mouse brain expressing human PRNP (lower panel). Substrates with compatible PRNP-codon 129 genotypes were used (VV in the case of VPSPr and sCJD VV2, and MM for both cases of GSS). The (seed:substrate) volume ratios were as follows: VPSPr cases (1:4), GSS and sCJD cases (1:9). Samples were amplified by PMCA (+) or kept frozen (-). The region of the ~8 kDa PrP^res band is indicated with a bracket. Separate immunoblots have been aligned to the molecular mass markers shown in lane M.