Fig. 3.
Representative immunoblot analysis of sPMCA products. Detection of PrPSc in filtrate was carried out by sPMCA. The products were first analysed by dot blot (A), and samples showing dot blot positivity were then confirmed as containing PrPSc by western blot (B). All samples were digested with PK before analysis, and the blots were probed with the anti-PrP antibody SHa31. sPMCA-positive samples are indicated (1-18). These include blinded control samples (2, 3), non-blinded control samples (9-12), and samples from filters removed at the following times (months) after bolus burial: 2m (5, 8), 3m (13,14), 4m (4), 6m (6), 7m (15, 16), 8m (1), 17m (7) or 25m (17, 18). For dot blotting, negative-control sPMCA reactions amplifying extract from two different control column water filter extracts are indicated (c; 7 replicate analyses for each extract). For western blotting, molecular mass markers (M) at 20 and 30 kDa are shown. Sc, PK-digested scrapie-positive brain sample as a western-blot-positive control