Figure 5. Sedimentation velocity, amplification index, and protease sensitivity of PrP^Sc present in frontal cortex of patients with sCJD Type MM1 (n = 6) and Type MM2 (n = 6) and fractionated by ultracentrifugation in sucrose gradient.

Fractions were collected from the bottom of the tubes and PK-treated or untreated samples were analyzed for PrP by (A) WB with biotinylated primary antibody 3F4 and secondary Streptavidin-Peroxidase complex. The WBs are typical examples of Other Neurological Disease (OND), Type 1 (sCJD MM1), and Type 2 sCJD (sCJD MM2) homozygous for methionine in codon 129 of PRNP gene. The cumulative plots of concentration of PrP^C (green bars), total PrP^Sc (blue bars), and rPrP^Sc (red bars) in sucrose fractions was determined with CDI before or after PK treatment in six cases of (B) sCJD type MM1 and six cases of (C) Type MM2. The bars represent average ± SEM (n = 6); CDI was performed in each sCJD case in triplicate. The amplification index (red squares) determined with QuIC and relative concentration of sPrP^Sc (blue circles) measured by CDI and QuIC in (D) MM1 (n = 6) and (E) MM2 (n = 6) sCJD PrP^Sc separated in sucrose gradient. The points and bars are average ± SEM; both QuIC and CDI were performed in triplicate for each sCJD case sample. The asterisk in WBs indicates the band of PK cross reacting with primary antibody. The molecular mass of the markers is in kDa.