Figure 6: Replication-competent PrPSc in brain after p.o. administration.
Whole brains from mice that received a p.o. administration of 127I-PrPSc were collected 3 and 24 hr post administration. Control tissue samples were from mice which received a mock injection. After precipitation with sarkosyl to remove tissue components that interfere with PMCA, samples were subjected to 4 serial rounds of PMCA, as described in Methods. Western blotting was performed with 6D11 antibody at a dilution of 1:10,000 after treatment of the samples with proteinase K. We employed non-radioactive iodine-127 to label PrPSc for PMCA analysis. Four brain samples obtained at a designated time are indicated 1 through 4, lanes + or − represent positive or negative control for PrPSc (RML), respectively. Lane C indicates non-PK digested 10% normal brain homogenate. The results indicate that 50% of brain samples have replication-competent PrPSc 3 hr and 24 hr after p.o. administration.
