Figure 5. RecPrP^res aggregates are similarly neurotoxic as PrP27-30.

RecPrP^res aggregates were produced by incubation for 24 hrs with 400 mM NaF followed by PK-digestion for 1 hrs at 37°C. 100, 50 and 25 nM of dialyzed recPrP^res aggregates were added to the medium of 1×10⁵ N2A neuroblastoma cells and cell viability was measured after 24 hrs of incubation using the MTT assay. As a negative control, the same volume of PBS was added to the well (control). Purified PrP27-30 from RML infected mice brain, soluble recPrP (recPrP) and the reaction buffer without protein (buffer) were also assayed as controls. All experiments were done in triplicate and the values correspond to the average ± standard error. The reduction of cell viability produced by addition of recPrP^res or PrP^Sc was highly significantly (P<0.001) different from soluble recPrP and the buffer control, as determined by student t-test.