Figure 3: Analysis of PrP oligomeric state by gel filtration. Brain homogenates from three iCJD and three sCJD cases were subjected to gel filtration. (A) and (B) PrP in individual fractions was detected by Western blotting with 3F4. (A) iCJD; (B) sCJD. The amounts of total PrP in gel filtration fractions from 25 to 83 were determined by densitometric analysis. There were mainly two peaks of PrP distribution in these fractions: PrP in fractions between 29 and 35 represents large aggregates with molecular weight greater than 2,000 kDa while PrP in fractions between 51 and 81 represents small oligomers or monomers with molecular weight smaller than 150 kDa. (C) Ratio of PrP in each fraction to total PrP in all fractions quantitated by densitometric analysis. No significant differences in PrP distribution profile were determined between iCJD (n = 5) and sCJD (n = 7).